US20110270025A1

Movatterモバイル変換

Info

Publication number: US20110270025A1
Application number: US13/076,139
Authority: US
Inventors: Pierre Fridez; Alain Jordan; Jean-Charles Montavon; Tiago Bertolote; Laurent Mosimann; Xavier Raemy; Razack Osseni; Xuan Mai Tu; Joël Bonny
Original assignee: Allergan Inc
Current assignee: Allergan Inc; Apollo Endosurgery Inc
Priority date: 2010-04-30
Filing date: 2011-03-30
Publication date: 2011-11-03
Also published as: WO2011135443A2; EP2604234A2; EP2604234A3; CA2797894A1; EP2604234B1; US9192501B2; US20140073848A1; AU2011246960B2; AU2011246960A1; ES2523967T3; WO2011135443A3; EP2563298A2

Abstract

A remotely adjustable remotely power gastric band system may include a control device, an implant electronic device, and an implantable gastric band. The control device may telemetrically power and communicate with the implant electronic device, which may be used for adjusting the diameter of the implantable gastric band. The implant electronic device may store the gastric band adjustment history records of a patient and regulate the power received from the control device. To improve transmission efficiency, the implant electronic device may adopt a double modulation scheme for communicating with the control device. Furthermore, the implant electronic device may detect and resolve motor blockage issues related to the implantable gastric band.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. Provisional Application No. 61/343,571, filed on Apr. 30, 2010, which is assigned to the assignee hereof and hereby expressly incorporated by reference herein.

FIELD

The present invention generally relates to medical systems and apparatus and uses thereof for treating obesity and/or obesity-related diseases, and more specifically, related to gastric band systems that are remotely adjustable and remotely powered by a wireless control device.

BACKGROUND

Adjustable gastric banding apparatus have provided an effective and substantially less invasive alternative to gastric bypass surgery and other conventional surgical weight loss procedures. Despite the positive outcomes of invasive weight loss procedures, such as gastric bypass surgery, it has been recognized that sustained weight loss can be achieved through a laparoscopically-placed gastric band, for example, the LAP-BAND® (Allergan, Inc., Irvine, Calif.) gastric band or the LAP-BAND AP® (Allergan, Inc., Irvine, Calif.) gastric band. Generally, gastric bands are placed about the cardia, or upper portion, of a patient's stomach forming a stoma that restricts the passage of food into a lower portion of the stomach. When the stoma is of an appropriate size that is restricted by a gastric band, food held in the upper portion of the stomach provides a feeling of satiety or fullness that discourages overeating. Unlike gastric bypass procedures, the gastric band apparatus are reversible and require no permanent modification to the gastrointestinal tract.

Over time, a stoma created by a gastric band may need adjustment in order to maintain an appropriate size, which is neither too restrictive nor too passive. Some non-invasive procedures for adjustment of gastric bands without the use of a hypodermic needle have been proposed. For example, a remotely adjustable gastric band is a medical device which allows a healthcare worker to adjust a gastric band without requiring hypodermic needles to connect to an implanted, subcutaneous access port. A handheld controller can be used to send radio frequency waves for powering and communicating with the implanted device. The implanted device can tighten or relax the gastric band as requested by the healthcare worker via the handheld controller.

Birk, et al., U.S. Patent Pub. No. 2010-0010291, and Birk, et al., U.S. Ser. No. 12/705,245, which are commonly-assigned and co-pending with the present application, are incorporated herein in their entirety by this specific reference. Both of these applications disclose certain approaches to implantable systems that may be relevant.

Some mechanically adjustable implantable devices have a disadvantage of becoming inoperable if the adjustment mechanism fails. Furthermore, because the motor and the driving mechanisms are located near the restricting band itself, they are more subject to strain and damage from the implantation process. Therefore, it is desirable to develop a remotely adjustable gastric band where the motor is separated from the restricting band to reduce the strain from the implantation process such that the risk of damage during implantation is decreased.

Thus, there continues to remain a need for more effective implantable motor systems for use with adjustable gastric bands, particularly such implantable motor systems with increased and more efficient motoring capability.

SUMMARY

Generally described herein are remotely adjustable and remotely powered gastric band systems, and methods of use thereof. The apparatus, systems and methods described herein aid in facilitating obesity control and/or treating obesity related dieses while being non-invasive once implanted.

In one embodiment, the present may provide a power system for use in conjunction with a gastric band coupled with an implantable antenna for receiving a telemetric signal from a remote control device. The power system may include a rectifying device coupled to the implantable antenna, and configured to rectify the received telemetric signal to form a DC input voltage at a DC input node, a power sensing device configured to receive the DC input voltage and generate a regulation signal when the DC input voltage exceeds a predetermined threshold, a regulation device coupled to the power sensing device, and configured to generate a regulation voltage based on the regulation signal, and a switching device coupled to the regulation device, and configured to generate a feedback signal having a frequency based on the regulation voltage.

In another embodiment, the present invention may provide a communication system for use in conjunction with a gastric band coupled with an implantable antenna for receiving a telemetric signal from a remote control device. The communication system may include a regulation device configured to generate a regulation voltage at a first node, the regulation voltage based on a margin between a DC input voltage and a predetermined threshold, a data path arranged in parallel with the regulation device, and configured to adjust the regulation voltage to a set voltage at a second node, the set voltage based partially on an output data sequence, and a frequency modulation device coupled to the second node, and configured to generate a frequency modulation signal having a modulated frequency corresponding to the set voltage.

In another embodiment, the present invention may provide a remotely powered and remotely adjustable gastric band system, which may include a remote control device configured to transmit a telemetric signal having an amplitude and a carrier frequency, an implantable power device telemetrically coupled to the remote control device, and configured to extract power from the telemetric signal and generate a feedback signal having a message frequency based on the extracted power, and a gastric band for forming a ventral ring surface around a stomach of a patient, the gastric band coupled to the implantable power device, and configured to receive the extracted power from the implantable power device and adjust the ventral ring surface in response to the telemetric signal.

In another embodiment, the present invention may provide a method for detecting motor blockage of a motor for use in conjunction with an implantable gastric band. The motor may include a motor coil for conducting a motor coil current and a plurality of gears for adjusting an inner ring surface of the implantable gastric band in response to the motor coil current. The method may include the steps of applying a voltage pulse across the motor coil, measuring a plurality of transient motor coil currents, measuring a maximum motor coil current, and detecting the motor blockage based on the plurality of transient motor coil currents and the maximum motor coil current.

In another embodiment, the present invention may provide a tangible computer medium for storing instructions, upon being executed by a processor, that cause the processor to perform a method, which may comprise the steps of receiving measurements of a plurality of transient motor coil currents conducted by a motor coil of a motor for use in conjunction with an implantable gastric band, receiving a measurement of a maximum motor coil current conducted by the motor coil, and detecting a blockage of the motor based on the measurements of the plurality of transient motor coil currents and the measurement of the maximum motor coil current.

In another embodiment, the present invention may provide a motorized gastric band system, which may include an implantable gastric band for forming a loop having a ventral surface for contacting a stomach of a patient, a motor coupled to the implantable gastric band, and including a motor coil for conducting a motor coil current, and a gear responsive to the motor coil current, and for adjusting the ventral surface of the implantable gastric band, and a processor coupled to the motor, and configured to receive measurements of a plurality of transient motor coil currents conducted by the motor coil, receive a measurement of a maximum motor coil current conducted by the motor coil, and detect a blockage of the motor based on the measurements of the plurality of transient motor coil currents and the measurement of the maximum motor coil current.

In another embodiment, the present invention may include a retractable antenna device for a remotely adjustable and remotely powered an implantable gastric band. The retractable antenna device may include a housing having a top wall and a bottom wall, a winding drum disposed within the housing and along the axle, the winding drum having a neck and a base, the winding drum is configured to rotate about an axis between a first position and a second position, an antenna disposed between the base of the winding drum and the bottom wall of the housing, a cable configured to coil around the neck of the winding drum when the winding drum is at the first position, and configured to uncoil and substantially extend outside of the housing when the winding drum is at the second position, and a locking device configured to lock the winding drum when the winding drum rotates from the first position to reach the second position, so that the winding drum remains stationary at the second position.

In another embodiment, the present invention may provide a remote control device for use in conjunction with a remotely adjustable and remotely powered implantable gastric band. The remote control device may include a handle, a display screen having a proximal side and a distal side, the proximal side positioned between the handle and the distal side, a sensing device configured to determine an orientation of the remote control device by sensing the relative position of the distal side and the proximal side of the display screen, and a processing device coupled to the sensing device, configured to transmit a display signal to the display screen for displaying an image on the display screen with a first image orientation or a second image orientation depending on the orientation of the remote control device, and configured to adjust the implantable gastric band.

In another embodiment, the present invention may provide a system for rapidly charging a remote control device for remotely adjusting and powering an implantable gastric band via a telemetric coupling. The system may include a battery for providing power to the remote control device, and having a battery voltage, and a charging station for charging the battery, the charging station configured to monitor the battery voltage of the battery, deliver a constant charging current to the battery until the battery voltage reaches a predefined threshold, and deliver a constant charging voltage to the remote control device thereafter to maintain the battery voltage.

In another embodiment, the present invention may provide a system for remotely adjusting and powering an implantable gastric band configured to be installed around a stomach of a patient. The system may include an implantable memory configured to be disposed inside the patient and to store a patient record relatable to the patient and an adjustment record relatable to an adjustment history of the implantable gastric band, and a processor coupled to the memory, and configured to retrieve the adjustment history upon receiving a telemetric data retrieval signal from a remote control device, generate a signal for adjusting the implantable gastric band upon receiving a telemetric band adjustment signal from the remote control device, and update the adjustment record based on the telemetric band adjustment signal.

In yet another embodiment, the present invention may provide an implantable gastric band, which may include a tubular member having a first end and a second end, the second end defining an opening, the first end having a flange configured to engage the second end of the tubular member, thereby forming a tubular ring having an adjustable ventral ring surface and a substantially rigid dorsal ring surface, a skeleton disposed between the adjustable ventral ring surface and the substantially rigid dorsal ring surface of the tubular ring, the skeleton having a distal end pushing against the first end of the tubular member and a proximal end pushing against the second end of the tubular member, the skeleton configured to support the substantially rigid dorsal ring surface of the tubular ring, a flexible screw slid between the skeleton and the adjustable ventral ring surface, the flexible screw having a hook anchoring the distal end of the skeleton and a crimped end extending beyond the opening of the tubular member, the flexible screw having an outer portion disposed outside of the tubular ring and an inner portion disposed inside of the tubular ring, the inner portion of the flexible screw defining a circumference of the adjustable ventral ring surface, a motor anchoring the proximal end of the skeleton and engaging the flexible screw, and configured to increase or decrease the inner portion of the flexible screw, thereby adjusting the circumference of the adjustable ventral ring surface, a processor for receiving an telemetric signal and for controlling the motor, and a cable having a processor end coupled to the processor and a motor end coupled to the motor.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, objects, and advantages of the invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, wherein:

FIG. 1 shows a perspective view of a remotely adjustable remotely powered (RARP) gastric band system according to an embodiment of the present invention;

FIG. 2 shows a perspective view of various external components of the RARP gastric band system according to an embodiment of the present invention;

FIG. 3 shows a block diagram of the RARP gastric band system according to an embodiment of the present invention;

FIG. 4 shows a system architecture block diagram of the RARP gastric band system according to an embodiment of the present invention;

FIGS. 5A-5B show the button configuration and display screen orientation of a control device according to an embodiment of the present invention;

FIG. 6 shows an exploded view of a control device according to an embodiment of the present invention;

FIG. 7 shows the perspective bottom and top views of a Human Interface Device (HID) Printed Circuit Board (PCB) being coupled to a Radio Frequency (RF) Printed Circuit Board (PCB) according to an embodiment of the present invention;

FIGS. 8A-8R show the sample screen shots of the control device according to an embodiment of the present invention;

FIG. 9 shows a schematic view of the HID subsystem according to an embodiment of the present invention;

FIG. 10 shows a perspective view of the HID PCB components and connectors according to an embodiment of the present invention;

FIG. 11 shows a schematic view of the RF subsystem according to an embodiment of the present invention;

FIG. 12 shows a perspective view of the RF PCB components and connectors according to an embodiment of the present invention;

FIG. 13 shows a schematic view of a power regulation subsystem of the RARP gastric band system according to an embodiment of the present invention;

FIG. 14 shows a schematic view of a modulation device according to an embodiment of the present invention;

FIG. 15 shows a diagram with an ideal voltage curve and an ideal current curve of a Class E amplifier according to an embodiment of the present invention;

FIG. 16 shows the adjustability of tail end of the voltage curve in the Class E amplifier according to an embodiment of the present invention;

FIG. 17 shows a schematic view of a rectifying device according to an embodiment of the present invention;

FIG. 18 shows an implant power regulation subsystem according to an embodiment of the present invention;

FIG. 19 shows various waveforms of various signals of the implant power regulation subsystem according to an embodiment of the present invention;

FIG. 20 shows various waveforms of a double modulation (frequency modulated amplitude modulation) scheme according to an embodiment of the present invention;

FIG. 21 shows a schematic view of a double modulation subsystem according to an embodiment of the present invention;

FIG. 22 shows a frequency chart of the double modulation scheme according to an embodiment of the present invention;

FIG. 23A shows a frequency spectrum of the frequency modulation feedback signal according to an embodiment of the present invention;

FIG. 23B shows a demodulation of the frequency modulated amplitude modulation signal according to an embodiment of the present invention;

FIG. 24 shows a schematic view of a demodulation device according to an embodiment of the present invention;

FIG. 25 shows the relationship among various signals of the demodulation device and a distance between the external antenna and the implant antenna according to an embodiment of the present invention;

FIG. 26 shows the communication protocol among the HID subsystem, RF subsystem and the implant according to an embodiment of the present invention;

FIG. 27 shows the state diagram of an HID subsystem algorithm according to an embodiment of the present invention;

FIG. 28 shows the state diagram of an RF subsystem algorithm according to an embodiment of the present invention;

FIG. 29A shows a command only communication protocol between the HID and RF subsystems according to an embodiment of the present invention;

FIG. 29B shows a command-data communication protocol between the HID and RF subsystems according to an embodiment of the present invention;

FIG. 30 shows an answer message communication protocol from the RF subsystem according to an embodiment of the present invention;

FIG. 31 shows a notification message communication protocol from the RF subsystem according to an embodiment of the present invention;

FIGS. 32A-32C show an exploded view, a front view and a back view of a docking station according to an embodiment of the present invention;

FIG. 33 shows a schematic view of the docking station interacting with the RF Board according to an embodiment of the present invention;

FIG. 34 shows a fast charge mode voltage-current chart according to an embodiment of the present invention;

FIGS. 35A-35B show a perspective view and an exploded view of an external antenna with a retractable cable according to an embodiment of the present invention;

FIGS. 36A-36B show a perspective front view and a perspective back view of the retractable external antenna being stored at the back of the control device according to an embodiment of the present invention;

FIGS. 37A-37B show a perspective view and an exploded view of the implant according to an embodiment of the present invention;

FIGS. 38A-38F show the perspective views of various implant electronic device protection case components according to an embodiment of the present invention;

FIGS. 39A-39B show a top view and a bottom view of an implant electronic system board according to an embodiment of the present invention;

FIGS. 40A-40C show various views of a manipulation handle according to an embodiment of the present invention;

FIG. 41 shows a state diagram of implant electronic device software algorithm according to an embodiment of the present invention;

FIGS. 42A-42B show a transmission sequence and a data structure of an identification message to the control device according to an embodiment of the present invention;

FIGS. 43A-43B show the command only protocol and a data structure of the command according to an embodiment of the present invention;

FIGS. 44A-44B show the command-parameter protocol and a data structure of the command-parameter according to an embodiment of the present invention;

FIGS. 45A-45B show the data structures of an ACK message and a NACK message according to an embodiment of the present invention;

FIG. 46A shows a command-response protocol according to an embodiment of the present invention;

FIG. 46B shows a data structure of a response message according to an embodiment of the present invention;

FIG. 47A shows a time out protocol with control device checksum according to an embodiment of the present invention;

FIG. 47B shows a time out protocol with implant checksum according to an embodiment of the present invention;

FIG. 48 shows a data structure of implant adjustment history record according to an embodiment of the present invention;

FIG. 49 shows a timing diagram of a computer interrupt upon a detection of a control device command at the implant according to an embodiment of the present invention;

FIG. 50 shows a timing diagram of the control device's command and the implant's response according to an embodiment of the present invention;

FIG. 51 shows a schematic view of a motor coil current measurement system according to an embodiment of the present invention;

FIG. 52 shows a graph for measuring an integral motor coil current according to an embodiment of the present invention;

FIG. 53 shows a graph for measuring a maximum motor coil current according to an embodiment of the present invention;

FIG. 54 shows a software algorithm for detecting motor blockage according to an embodiment of the present invention;

FIGS. 55A-55B show a perspective top view and a perspective bottom view of a motor according to an embodiment of the present invention;

FIGS. 55C-55D show a perspective bottom view and a perspective top view of a motor cap according to an embodiment of the present invention;

FIGS. 55E-55F show a perspective bottom view and a perspective top view of a motor traveling PCB protection cap according to an embodiment of the present invention;

FIGS. 55G-55H show a perspective side view and a side view of a motor sleeve according to an embodiment of the present invention;

FIG. 55I shows an exploded view of a motor coil according to an embodiment of the present invention;

FIGS. 55J-55K show various views of the motor cable according to an embodiment of the present invention;

FIG. 56 shows a side view of a flexible screw according to an embodiment of the present invention;

FIGS. 57A-57H show various views of the motor engaging the flexible screw according to an embodiment of the present invention;

FIGS. 58A-58C show various views of a bendable skeleton embedded with a stabilizing tube according to an embodiment of the present invention;

FIGS. 59A-59B show a perspective view and a cross-sectional view of the stabilizing tube according to an embodiment of the present invention;

FIGS. 60A-60D show various views of a dorsal element according to an embodiment of the present invention;

FIGS. 61A-61C show various views of an anti-slip cushion according to an embodiment of the present invention;

FIGS. 62A-62C show various views of a membrane shell according to an embodiment of the present invention; and

FIGS. 63A-63C show various views of a cushioned membrane shell according to an embodiment of the present invention.

DETAILED DESCRIPTION

InFIG. 1, a remotely adjustable and remotely powered (RARP)gastric band system100 is shown according to an embodiment of the present invention. Generally, the RARPgastric band system100 may include an external subsystem and an implant (internal) subsystem. The external subsystem may include a control device (a.k.a. control unit)110, anexternal antenna120, and aretractable antenna cable114, which may be used for coupling theexternal antenna120 to thecontrol device110.

From a high level standpoint, thecontrol device110 may serve various functions. In one embodiment, for example, thecontrol device110 may be used as an interface for a user, such as a physician or a care taker. In another embodiment, for example, thecontrol device110 may be used for transmitting telemetric signal122 to theimplant130 for inducing power therein. In yet another embodiment, for example, thecontrol device110 may be used for remotely controlling various functionalities of theimplant130, such as adjusting the size of agastric band180, retrieving information from theimplant memory device150, and/or regulating power inside theimplant130.

The implant subsystem (a.k.a. the implant)130 may be implanted inside a patient'sbody101, and it may include an implantelectronic device132, agastric band180, amotor170, and amotor cable142. Thegastric band180 may be used for forming a stoma around the patient'sstomach102, and themotor170 may be used for controlling thegastric band180, which may in turn, adjust the size of the stoma. Moreover, the implantelectronic device132 may include an implant (internal)antenna160, a microprocessor (a.k.a. microcontroller)140, and amemory device150.

From a high level standpoint, themicroprocessor140 may serve various functions. In one embodiment, for example, themicroprocessor140 may coordinate the reception, rectification, and regulation of power received via theimplant antenna160. Generally, theimplant antenna160 may receive the signal transmitted from theexternal antenna120 when they are separated by a distance of about 3 cm or less. In another embodiment, for example, themicroprocessor140 may retrieve past gastric band adjustment information from thememory device150 or store current gastric band adjustment information to thememory device150. In yet another embodiment, for example, themicroprocessor140 may control themotor170 for adjusting thegastric band180, and for detecting and preventing motor blockage.

InFIG. 2, a perspective view of various external subsystem components of the RARPgastric band system100 are shown according to various embodiments of the present invention. In addition to thecontrol device110 and theexternal antenna120, theexternal subsystem200 may include a carryingcase201, apower adaptor202, apower cord204, and adocking station208.

Thepower adaptor202 may connect a power source (not shown) to thedocking station208, such that thedocking station208 may receive electricity for charging thecontrol device110. Theexternal antenna120 may be connected to the control device110 (interchangeably “control unit”) during gastric band adjustment. Theexternal antenna120 may be stored at the back of thecontrol device110 when it is not in use. In between gastric adjustments, thecontrol device110 may be docked at thedocking station208 for recharging. The connection between thecontrol device110 and thedocking station208 may be established by contacting several spring loaded connectors located on thedocking station208 with several matching metallic surfaces located on thecontrol device110. The spring loaded connectors and the matching metallic surfaces may provide additional physical stability when the control device206 is docked at thedocking station208.

FIG. 3 shows a block diagram of a RARPgastric band system300 according to an embodiment of the present invention. Generally, the RARPgastric band system300 may include thecontrol device110, thedocking station208, theexternal antenna120, and theimplant130. Particularly, thecontrol device110 may include a Human Interface Device (HID)board310 and a Radio Frequency (RF)board320.

TheHID board310 may be used for implementing an HID subsystem. The HID subsystem may receive input from a user and generate output for the user during or in between gastric band adjustments. As such, a physician and/or a care taker may use the HID subsystem to adjust the size of the gastric band and to retrieve information regarding the gastric band adjustment history of a particular patient. The size of the gastric band can be understood as diameter of a ventral (inner) ring surface of the gastric band.

TheRF board320 may be used for implementing an RF subsystem. The RF subsystem may execute various tasks as instructed by the HID subsystem. Generally, the HID subsystem and the RF subsystem may setup a master-slave configuration324, in which the HID subsystem may command the RF subsystem to perform a recharging task, a power transmission task, a band adjustment task, and/or an information retrieval task.

To perform the recharging task, the RF subsystem may establish apower connection326 with thedocking station208. Thepower connection326 may be used for transmitting power from thedocking station208 to theRF board320. Moreover, thepower connection326 may conduct signals that may be used for monitoring and controlling the recharge process.

To perform the power transmission task, the RF subsystem may drive theexternal antenna120 with an RF signal that induces power in theimplant130. Generally, the RF signal may be amplitude modulated and have a carrier frequency within the radio frequency range. In one embodiment, for example, the carrier frequency may range from about 30 kHz to about 300 GHz. In another embodiment, for example, the carrier frequency may range from about 10 MHz to about 50 MHz. In yet another embodiment, for example, the carrier frequency may approximately be about 27 MHz.

To perform the band adjustment task, the RF subsystem may momentarily transmit adjustment instruction via theexternal antenna120 to theimplant130. The transmission of the adjustment instruction may include a series of handshake protocols, which may ensure that the adjustment instruction is being received and executed properly by theimplant130.

To perform the information retrieval task, the RF subsystem may sense and demodulate a feedback signal from theimplant130. Generally, the feedback signal may be a double modulation signal, which may include a frequency modulation component and an amplitude modulation component. In one embodiment, for example, the frequency modulation component may be used for embedding gastric band adjustment data and power regulation signal while the amplitude modulation component may be used as a carrier. In another embodiment, for example, the amplitude modulation component may be used for embedding gastric band adjustment data and power regulation signal while the amplitude modulation component may be used as the carrier.

FIG. 4 shows a system architecture block diagram of a RARPgastric band system400 according to an embodiment of the present invention. Generally, the RARPgastric band system400 may include anexternal system410 and an implant (internal)system470. Theexternal system410 may include anHID subsystem420, anRF subsystem430, anexternal antenna440, adocking station450, and arechargeable battery460. Theimplant system470 may include animplant antenna472, anRF transponder subsystem473, apower management subsystem474, an implant microcontroller (microprocessor)476, and amotor interface device478. TheRF transponder subsystem473 may include various electronic components connecting theantenna472 and themicrocontroller476. For example, theRF transponder subsystem473 may include rectifying circuits and a LTC6900 chip.

TheHID subsystem420 may include: several input keys (buttons)425 for receiving input from a user, a video device (OLED Display)427 for outputting visual information to the user, anaudio device426 for outputting audio information to the user, a real-time control (RTC)device424 for monitoring the charge level of therechargeable battery460, an HID microcontroller (microprocessor)421 for processing information received from thekeys425 and theRTC device424. In order to store and retrieve various data, theHID subsystem420 may include several memory devices, such as adata flash device428, aserial flash device422, aSRAM device423, and anoptional EEPROM device429.

TheRF subsystem430 may include: anEEPROM device432 for storing various data, an RF microcontroller (microprocessor)431 for performing various tasks requested by theHID microcontroller421, anRF transponder434 for driving and receiving information from theexternal antenna440, and abattery management device436 for interfacing with thedocking station450 and for controlling the recharging of thebattery460.

FIGS. 5A-5B show the button configuration and display screen orientation of acontrol device500 according to an embodiment of the present invention. Generally, the front surface of thecontrol device500 may include adisplay screen502, a power button (sensor)532, a first set of auxiliary buttons (sensors)504,506, and508, a second set of auxiliary buttons (sensors)534,536, and538, and a set of adjustment control buttons (sensors), such as a band open button (sensor)540, a stop adjustment button (sensor)542, and a band close button (sensor)544.

The first and second set of

auxiliary buttons

504,506,508,534,536, and538 may be configured to adapt to both left-handed and right-handed users. In one embodiment, for example, the button configuration and the display screen orientation as shown inFIG. 5A may be used by a left-handed user. Particularly, in the left-handed configuration (orientation), the first set of

auxiliary buttons

504,506, and508 may be inactivated or disabled, whereas the second set of

auxiliary buttons

534,536, and538 may serve as the left, center, and right buttons, respectively.

In another embodiment, for example, the button configuration and the display screen orientation as shown inFIG. 5B may be used by a right-handed user. Particularly, in the right-handed configuration, the second set of

auxiliary buttons

534,536, and538 may be inactivated or disabled, whereas the first set of

auxiliary buttons

504,506, and508 serve as the right, center, and left buttons, respectively.

As the first and second set of

auxiliary buttons

504,506,508,534,536, and538 are being reconfigured, thedisplay screen502 may be reoriented as well. When the second set of

auxiliary buttons

534,536, and538 are activated, thedisplay screen502 may have a first (left-handed) orientation as shown inFIG. 5A. When the first set of

auxiliary buttons

504,506, and508 are activated, thedisplay screen502 may have a second (right-handed) orientation as shown inFIG. 5B. Generally, thecontrol device500 may have a gyroscopic device (not shown) for sensing its orientation. Particularly, thecontrol device500 may use the sensed orientation to generate one or more signals for reconfiguring the first and second set of

auxiliary buttons

504,506,508,534,536, and538, and for reorienting thedisplay screen502.

FIG. 6 shows an exploded view of acontrol device600 according to an embodiment of the present invention. Thecontrol device600 may include abottom shell601, abottom shell lid602, abattery pack603, aleft battery holder604, aright battery holder605, a metal plate606, amagnet607, ametal pad608, anRF PCB609, aregulatory sticker610, anRF cable611, atop shell612, abottom shell613, anadhesive display glass614, adisplay glass615, anauxiliary buttons group616, an adjustmentcontrol buttons group617, apower button618, adisplay OLED619, aGasket display620, and anHID PCB621. As shown inFIG. 6, the components of the control device can be grouped as the top shell assembly (right) and the bottom shell assembly (left). The two assemblies can be snapped or screen fastened together after theHID PCB621 and theRF PCB609 are properly coupled as shown inFIG. 7.

FIGS. 8A-8R show the sample screen shots of the control device according to an embodiment of the present invention. InFIG. 8A, the control device may be powered up and it may display a “Welcome” screen, which include a logo and/or a slogan. InFIG. 8B, the control device may display the “Code Entering” screen for receiving authentication information. In the “Code Entering” screen, abattery strength symbol801 and a usercode request message802 may be displayed. Accordingly, a user may enter a four-digit access code803. Particularly, the user may use the left auxiliary button, which may be associated with theplus sign804, to increase the value of a digit, the center auxiliary button, which may be associated with theminus sign805, to decrease the digit value, and the right auxiliary button, which may be associated with thearrow sign806, to go to the next digit and eventually to accept the entry.

InFIG. 8C, the control device may display the “Antenna Search” screen, in which the user may be instructed to place the external antenna near the implant antenna. A number of reception bars807 may be shown in the “Antenna Search” screen once the control device detects a nearby implant antenna. The number of reception bars807 may indicate the strength of the connection between the external antenna and the implant antenna. For example, a signal strength represented by two or less reception bars807 may be considered insufficient, whereas a signal strength represented by three or more reception bars807 may be considered sufficient.

InFIGS. 8D and 8E, the control device may display the “Loading” screens once the control device detects a signal strength represented by two or more reception bars807. The “Loading” screens may show the progress of downloading the patient's information from the implant.

Once the downloading is complete, the control device may display the “Adjustment” screen (a.k.a. “Default” screen) as shown inFIG. 8F. In the “Adjustment” screen, the user may adjust the implanted gastric band. In adjusting the implanted gastric band, the user may use the band open button, which may be associated with the bandopen symbol812, and the band close button, which may be associated with the bandclose symbol813. Moreover, the user may choose to perform other functions. In one embodiment, for example, the user may use the left auxiliary button, which may be associated with thechart symbol814, to review the past adjustment history of a patient. In another embodiment, for example, the user may use the center auxiliary button, which may be associated with thecode change symbol815, to change the password (or pass code) of the control device. In yet another embodiment, for example, the user may use the right auxiliary button, which may be associated with thelock symbol816, to lock the control device.

When the user presses or selects the open band button, the control device may display the “Opening” screen as shown inFIG. 8G. In the “Opening” screen, the user may increase the size of the patient's stoma by loosening the implanted gastric band. Alternatively, when the user presses or selects the close band button, the control device may display the “Closing” screen as shown inFIG. 8H. In the “Closing” screen, the user may decrease the size of the patient's stoma by tightening the implanted gastric band. The user may press the stop button to stop the loosening process or the tightening process to terminate the adjustment process, after which the “Adjustment” screen may be reloaded.

When the user selects the chart function, the control device may display the “Adjustment History Plot” screen as shown inFIG. 8I. In the “Adjustment History Plot” screen, the user may use the left or center auxiliary button, which may be associated with the left and right arrow signs818, to view previous and/or current records. Alternatively, the user may use the right auxiliary button, which may be associated with thelist symbol817, to view the adjustment history list.

When the user selects the adjustment history list, the control device may display the “Adjustment History List” screen as shown inFIG. 8J. In the “Adjustment History List” screen, the user may use the left or center auxiliary button, which may be associated with the up and downarrow signs818, to view previous and/or current records. Alternatively, the user may use the right auxiliary button, which may be associated with theforward symbol819, to return to the “Adjustment History Plot” screen.

Referring again toFIG. 8F, the user may lock thecontrol device110 by selecting thelock symbol816. When thecontrol device110 is locked, the control device may display the “Locked” screen as shown inFIG. 8K. To exit the “Locked” screen, the user may press any button except for the power button. Then, the control device may display the “Code Entering” screen as shown inFIG. 8B. In the “code entering” screen, the user may be instructed to enter the pass code again.

Referring again toFIG. 8F, the user may change the old pass code by selecting thecode change symbol815. As shown inFIG. 8L, the control device may display the “Old Code Entering” screen, in which the user may enter the old pass code. After receiving and verifying the validity of the old pass code, the control device may display the “New Code Entering” screen as shown inFIG. 8M. After receiving thenew code822, the control device may display the “Confirm or Cancel Code” screen as shown inFIG. 8N. At this point, the user may select the left auxiliary button, which may be associated with theOK symbol804, to accept thenew code822, or select the right auxiliary button, which may be associated with the CANCELsymbol825, to cancel thenew code822. Upon receiving the confirmation, the control device may display the “Code Changed” screen as shown inFIG. 80.

As shown inFIG. 8P, the “Battery Recharge” screen may be displayed when the control device is being recharged. The “Adjustment” screen may return once the control device is disconnected from the docking station.FIGS. 8Q and 8K show the “Error Message” screens, which may notify the user with warning messages. For example, the “Error Message” screen may notify the user when the implant is malfunction or when the battery level is low.

Table 1 below may provide a summary of screen shot with respect to the button functionality.

TABLE 1

Button assignments for the different screen shots.

Activated Auxiliary Buttons

Screen shot	Left	Center	Right

Welcome	N/A	N/A	N/A
Code Entering	Increase value	Decrease value	Next digit
Antenna Search	N/A	N/A	N/A
Loading	N/A	N/A	N/A
Adjustment	History plot	Code Change	Lock
Opening	N/A	N/A	N/A
Closing	N/A	N/A	N/A
History Plot	Previous point	Next point	List
History List	Scroll up	Scroll down	Adjustment
Locked	Code entering	Code entering	Code entering
Old Code	Increase value	Decrease value	Next digit
New Code	Increase value	Decrease value	Next digit
Confirm Code	Confirm	N/A	Cancel
Code Changed	N/A	N/A	Adjustment
Battery Recharge	N/A	N/A	N/A
Error Message	Adjustment	N/A	N/A
Warning	N/A	Adjustment	N/A

Referring toFIG. 9, a schematic view of theHID subsystem900 is shown according to an embodiment of the present invention. Generally, theHID subsystem900 may include eleven device blocks, such as amicrocontroller block902, amemory block904, adisplay screen block906, a buzzer andvibrator block908, asound interface block910, an accelerometer and RTC block914, aninterface block918, aUSB block920, aninput button block916, a JTAG/TRACE connector block922, and apower supply block912.

Referring toFIG. 10, a perspective view of theHID PCB1000 is shown according to an embodiment of the present invention. Generally, each of the components on theHID PCB1000 may be included in, associated with, or controlled by one of the eleven device blocks of theHID subsystem900.

Themicrocontroller block902 may include the microcontroller device (microprocessor)1004, which may be configured as the master of the control device and may control all the user interface components, such as the display screen, the buttons, the sound interface, and the memory. Themicrocontroller block902 may also include a crystal oscillator, two pull-down resistors and a pull-up resistor. Thememory block904 may include a 128-Mb flash memory1034 and a 1-Mb EEPROM1046, along with five pull-up resistors and four regulating capacitors.

Thedisplay screen block906 may include an OLED display, an OLED displayflat connector1048 and a display driver supply (not shown). The buzzer and vibrator block908 may include various components for driving abuzzer1038 and avibrator1008. Thesound interface block910 may include anaudio power amplifier1010, which may be connected to the speaker (not shown). The accelerometer and RTC block914 may include an RTC chip1041 and aPC30 accelerometer chip1035 as well as alithium ion battery1044 for back-up power.

Theinput button block916 may include a power button (not shown) for sending power up signals to the HID PCB and the RF PCB. Theinput button block916 may also include two set of triplet buttons (auxiliary buttons) selectable by three output keys. Theinterface block918 may include two

connectors

1050 and1052 for connecting cards together and for connecting between RF PCB. TheUSB block920 may include two

mini USB connectors

1020 and1030, an ESD input protection chip (not shown), and an RS232 translator chip FT232RL (not shown). TheJTAG block922 may include two connectors (not shown). Finally, thepower block912 may comprise a 3.3V voltage regulator (not shown) and several 3.3V power connections.

Referring toFIG. 11, a schematic view of theRF subsystem1100 is shown according to an embodiment of the present invention. Generally, theRF subsystem1100 may include seven device blocks, such as amain controller block1104, amodulation block1106, ademodulation block1108, anauxiliary controller block1110, an RF power supplies block1112, asystem power block1101, and abattery block1102.

Referring toFIG. 12, a perspective view of theRF PCB1200 is shown according to an embodiment of the present invention. Generally, each of the components on theHID PCB1200 may be included in, associated with, or controlled by one of the seven device blocks of theRF subsystem1100.

The RFmain controller block1104 may include a microcontroller (processing device)1201, which may perform as a slave to theHID microcontroller block902. TheRF microcontroller1201 may control the power induction in the implant, the charging circuitry in the docking station, the communication to and from the implant, and the communication with theHID microcontroller block902. TheRF microcontroller1201 may further receive multiple monitoring inputs and the reset command from theHID microcontroller block902. The USB connection may be established through amini USB connector1274 with the USB protocol translated into a UART serial interface through an RS232 translator chip (not shown).

Themodulation block1106 may include aclass E amplifier1234 for generating an amplitude modulation signal with carrier frequency at about 27 MHz. Particularly, themodulation block1106 may be involved in generating a 27 MHz carrier frequency with an amplitude that equals the RF supply voltage VSUP, while the data signal may contain the digital command being sent to the implant via the external antenna.

Thedemodulation block1108 may include aFM demodulator chip1208 to demodulate the signals received from the implant and extracted from the external antenna via adirectional coupler1272. As such, theFM demodulator chip1208 may be used for retrieving useful information, such as the received signal strength RSSI and the feedback message from the implant. TheRF demodulator chip1208 may also generate regulating signals, including REG_LEVEL, VSUP_CTRL, VSUP, and FORCE_RF_LEVEL.

The power supplies block may comprise a LT1961 voltage regulator (not shown), the amplitude of which may be controlled by either the VSUP_CTRL input indirectly from the implant or the DAC IN input from the RF controller. The VSUP_CTRL input helps implement the control loop between the implant and the control device which adjusts the power induced in the implant. TheRF microcontroller1201 may also shutdown VSUP through the VSUP_ON/OFF input. Moreover, VSUP_INHIBIT1 may shutdown VSUP whenever the control device is powered from an external source to avoid any danger to the patient from power line surges. BSUP_INHIBIT2 may provide another shutdown path from the auxiliary controller block.

Theauxiliary controller block1110 may include anauxiliary controller1244 and the associating connectors. Theauxiliary controller1244 may allow the overall system to implement a software oriented version of the implant power induction control.

Thesystem power block1101 may comprise theLM22672M voltage regulator1256 for regulating the power supplies at 3.6V, the LP2985-33voltage regulator U181276 for regulating the power supplies at 3.3V, and several monitoring signals indicating the power being turned on (KON), the presence of external power (EXTPWR_PRESENT) and the current load to the battery (ILOAD). Thebattery block1102 may include a battery management relatedcircuitry1268, the

battery connectors

1246 and1264, as well as two batteries connected in series, which may be monitored by the signals BATMON, BATMONZ, BATT_TH, EXT_BAT_MES1 and EXT_BAT_MES2.

The discussion now turns to the power regulation subsystem of the remotely adjustable remotely power (RARP) gastric band system. Referring toFIG. 13, a schematic view of apower regulation subsystem1300 is shown according to an embodiment of the present invention. Generally, thepower regulation subsystem1300 may be implemented by various devices (blocks) of the RF Board and of the Implant. The RF Board may include a modulation device (block)1320, anexternal antenna1324, a demodulation device (block)1330, a power supply device (block)1340, and a controller device (block)1310. The Implant may include animplantable antenna1352, a rectifying device (first device block)1350, a maximum power sensing device (second device block)1360, a regulation device (third device block)1370, and an impedance switching device (fourth device block)1380.

To initiate the power induction process, thecontroller device1310 may send atransmission signal1312 to enable themodulation device1320. Depending on the operation mode of the RF Board, thetransmission signal1312 can be activation based or interrupt based. After being enabled, themodulation device1320 may generate an amplitude modulation signal for driving theexternal antenna node1322. Theexternal antenna node1322 may be a transmission line that couples between theexternal antenna1324 and themodulation device1320. As a result, theexternal antenna1324 may transmit atelemetric signal1326 according to the amplitude modulation signal.

Thetelemetric signal1326 may travel across air and penetrate the body tissue of the patient, such that it may be received by theimplantable antenna1352. Based on the principles of electromagnetic induction, an alternate current (AC) may be induced at theimplant antenna node1354. Therectifying device1350 may rectify the voltage associate with the alternate current, so as to deliver a DC input voltage (V_IN) on the DC input voltage (V_IN)node1356. The maximumpower sensing device1360 may monitor the level of the DC input voltage V_IN. When the DC input voltage V_INexceeds a certain predetermined threshold voltage value, the maximumpower sensing device1360 may generate aregulation signal1362 to activate theregulation device1370.

After being activated, theregulation device1370 may generate aregulation voltage1372. The magnitude of which may depend on a voltage difference (potential difference) between the DC input voltage V_INand the predetermined threshold voltage value. Thus, the magnitude of theregulation voltage1372 may represent or indicate the amount of regulation that may be needed. Generally, the DC input voltage V_INmay be a function of a transmission distance between theexternal antenna1324 and theimplantable antenna1352. When the transmission distance decreases, the signal strength of thetelemetric signal1326 may increase, thereby causing the DC input voltage V_INto rise. Thus, as theexternal antenna1324 approaches theimplantable antenna1352, theregulation voltage1372 may increase. In order to communicate the need to regulate with the RF Board, theregulation voltage1362 may be used for generating one or more feedback signals and/or messages.

The impedance switching device (switching device)1380 may receive and process theregulation voltage1362. After processing theregulation voltage1362 along with other signals, theimpedance switching device1380 may couple and decouple the DC input voltage V_INnode1356 to and from an additional impedance component at a feedback frequency. Generally, the feedback frequency may be determined based on theregulation voltage1362 and some other factors. In one embodiment, for example, the feedback frequency may be inversely proportional to theregulation voltage1362. In another embodiment, for example, the feedback frequency may be directly proportional to theregulation voltage1362.

By switching on and off the additional impedance component, theimpedance switching device1380 may generate afeedback signal1382, which may superimpose the regular DC input voltage V_IN. That is, the overall load impedance (Z_LOAD) may be adjusted by the feedback frequency offeedback signal1382.

According to the principle of mutual inductance, the fluctuation of the overall load impedance and/or thefeedback signal1382 may manifest as apassive telemetric signal1356, which may be received by theexternal antenna1324. Consequently, the feedback frequency of the feedback signal may be seen as a message (envelop) frequency of thepassive telemetric signal1357.

In order to separate thepassive telemetric signal1357 from the outbound amplitude modulation signal, the RF Board may use a sensing device (block)1332 to sense or extract afeedback profile1334 of thepassive telemetric signal1357 from theexternal antenna node1322. Thefeedback profile1334 may have a frequency tracking the feedback frequency of the feedback signal. In one embodiment, for example, thesensing device1332 may be a directional coupler. Thedemodulation device1330 may receive thefeedback profile1334 and determine and/or extract the message frequency embedded in thefeedback profile1334.

Consequentially, thedemodulation device1330 may generate a voltagesupply control signal1336 based on the feedback frequency. Thepower supply device1340 may process the voltagesupply control signal1336 and regulate theRF supply voltage1342 accordingly. Because themodulation device1320 may be powered by theRF supply voltage1342, the amplitude modulation signal may be indirectly regulated by thepower supply device1340. As a result, the power induced by the amplitude modulation signal may be increased or decreased depending on thefeedback signal1382.

More specifically, the amplitude modulation signal may have a carrier frequency and a magnitude (modulation amplitude). Depending on the load impedance, the carrier frequency may be selected from a range of radio frequencies (about 30 kHz to about 300 GHz) for maximum power transfer. For example, the carrier frequency may be about 27 MHz when the load impedance is about 50Ω.

The modulation amplitude may be controlled by theRF supply voltage1342, and it may determine the amount of power being transferred from the RF Board to the implant. Thus, power transfer may be regulated by adjusting the modulation amplitude, which may depend on theRF supply voltage1342. For example, when the implant receives excessive power, which may cause overheating in the implant, theRF supply voltage1342 may be lowered to reduce the modulation amplitude of the amplitude modulation signal. For another example, when the implant receives insufficient power, which may cause the implant to be turned off, theRF supply voltage1342 may be augmented to increase the modulation amplitude of the amplitude modulation signal.

InFIG. 14, a schematic view of amodulation device1400 is shown according to an embodiment of the present invention. Generally, themodulation device1400 may be used for implementing the functional features of themodulation device1320. Particularly, themodulation device1400 may include an activation block (activation device path)1430 for enabling or disabling the generation of the amplitude modulation signal, anoscillating device1450 for generating acarrier frequency signal1452, and a class E amplifier block (amplifier device path)1410 for generating theamplitude modulation signal1420. Theoscillating device1450 may be a crystal oscillator, and it may be used for controlling the carrier frequency of the amplitude modulatedsignal1420.

Theactivation block1430 may include afirst stage amplifier1432 for amplifying thetransmission signal1312, and asecond stage amplifier1434 for generating adata override signal1436. Generally, thecarrier frequency signal1452 may be buffered by afirst stage inverter1453 and asecond stage inverter1454. Although thefirst stage inverter1453 may be powered on by a separate power source, thesecond stage inverter1454 may be enabled or disabled by thedata override signal1436.

When the RF Board is powering the implant, thedata override signal1436 may be low, such that thecarrier frequency signal1452 may drive a switchingnode1401. Alternatively, when the RF Board is transmitting data, thedata override signal1436 may be high, such that thesecond inverter stage1454 may be turned off momentarily during data transmission. As a result, thecarrier frequency signal1452 may be blocked from driving theswitching node1401.

The classE amplifier block1410 may have acommon source stage1404 for driving a firstintermediate node1402. The output of thecommon source stage1404 may have a frequency component, which may be controlled by thecarrier frequency signal1452 of theoscillating device1450, and an amplitude component, which may be controlled by theRF supply voltage1342. Depending on the regulation level, the amplitude component may change as the transmission distance varies. In one embodiment, for example, the amplitude component may range from about 3 V to about 16 V. In another embodiment, for example, the amplitude component may range from about 5V to about 14 V. As discussed earlier, the power induced in the Implant may be regulated by adjusting the amplitude component of theamplitude modulation signal1420, which may be dictated by theRF supply voltage1342.

Referring toFIG. 15, the classE amplifier block1410 may have a relatively low sensitivity to any variation in the load Z_L, and it may have a high efficiency as long as the transitions at the(common source state)MOS switch1404 occur while the current or the voltage is null. Referring toFIG. 16, the capacitor C2 and the impedance Zh2 may be the adjustable components in theamplifier block1410, such that the transition point may be moved left and/or right by adjusting the value of the capacitor C2, and it may be moved up and/or down by adjusting the value of the impedance Zh2.

InFIG. 17, a schematic view of arectifying device1700 is shown according to an embodiment of the present invention. Generally, therectifying device1700 may implement the functional features of therectifying device1350 as discussed inFIG. 13. Particularly, therectifying device1700 may include afirst capacitor1712, asecond capacitor1714, afirst diode1722, and asecond diode1724. More specifically, the first and

second capacitors

1712 and1714 may function as a pair of charge storage (or bootstrap) devices, while the first and

second diodes

1722 and1724 may function as a pair of voltage directing devices.

Themodulation device1320 may drive theexternal antenna1324 with anamplitude modulation signal1701, which may generate an alternate current in theexternal antenna1324. As a result, electromagnetic waves may be emitted from theexternal antenna1324, and they may propagate through air and penetrate the body tissue of the patient. A small portion of the electromagnetic waves may be absorbed by asecondary parasite1704, while a large portion of the electromagnetic waves may inducealternate voltage1703 in theimplantable antenna1352.

The amplitude of the inducedvoltage1703 may be affected by a transmission distance1720 separating theexternal antenna1324 and theimplantable antenna1352. For example, the amplitude of the inducedvoltage1703 may decrease when the transmission distance1720 increases from 10 mm to 20 mm. For another example, the amplitude of the inducedvoltage1703 may increase when the transmission distance1720 decreases from 35 mm to 20 mm.

The inducedvoltage1703 may be rectified by the first and

second diodes

1722 and1724. As a result, theoutput nodes1730 of therectifying device1700 may deliver the DC input voltage (V_IN)1705. The two-diode configuration may allow the V_INto have a relatively high magnitude, which may be slightly less than two times of the inducedvoltage1703. When thetransmission distance1702 is large (e.g. greater than 35 mm), it is advantageous to have the relative high magnitude V_INto compensate the energy loss to thesecondary parasite1704. However, when thetransmission distance1702 is small (e.g. less than 10 mm), the relative high magnitude V_INmay be problematic because it may produce excessive energy, which may lead to overheating within the implant.

To prevent overheating, the Implant may include a power regulation subsystem to provide feedback information to adjust the output energy of the modulation device. InFIG. 18, an implant power regulation subsystem (a.k.a. the power system)1800 is shown according to an embodiment of the present invention. Generally, the implantpower regulation subsystem1800 may include the maximum power sensing device (second device block)1360, the regulation device (third device block)1370, and the impedance switching device (fourth device block)1380.

The maximumpower sensing device1360 may include aZener diode1862 and a first pull downresistor1844. In one configuration, the positive terminal of theZener diode1862 may be coupled to the DC input voltage (V_IN) node and the negative terminal of theZener diode1862 may be coupled to the first pull downresistor1844, which may be coupled to an internal ground node. TheZener diode1862 may have a breakdown voltage V_BDacross its positive and negative terminals. When the DC input voltage (V_IN) is less than the breakdown voltage V_BD, theZener diode1862 may be under forward bias, such that theZener diode1862 is unlikely to sink any current from the DC input voltage (V_IN) node. As a result, the first pull downresistor1864 may pull the regulation signal to ground.

However, when the DC input voltage (V_IN) reaches and/or exceeds the breakdown voltage V_BD, theZener diode1862 may be under reverse bias, such that theZener diode1862 may begin to draw a breakdown current I_BDfrom the DC input voltage (V_IN) node. As a result, theregulation signal1362 may maintain a voltage level V_Racross the first pull downresistor1864. Depending on the design goal, the breakdown voltage V_BDmay be predetermined to accommodate the power consumption of the implant. That is, the breakdown voltage V_BDmay be chosen at a range that is substantially equal to or close by the predetermined threshold voltage. In one embodiment, for example, the breakdown voltage V_BDmay be about 3 V. In another embodiment, for example, the breakdown voltage V_BDmay be about 7 V. In yet another embodiment, for example, the breakdown voltage V_BDmay be about 5.6 V.

Although the sinking of the breakdown current I_BDmay have little effect on the V_INvalue, it may help generate theregulation signal1362. The voltage level V_Rof theregulation signal1362 may indicate or represent a desirable level of regulation. Mainly, the breakdown current I_BDmay be highly sensitive to the change of V_INvalue, so that the regulation signal voltage level V_Rmay track closely to the amount of the excessive DC input voltage V_IN.

Theregulating device1370 may include avoltage regulator1872, a first pull upresistor1874, a second pull upresistor1875, atransistor1876, and a second pull downresistor1878. Thevoltage regulator1872 may be used for generating a relatively constant local voltage V_CCat a first node (e.g., the V_CCnode). The constant local voltage V_CCmay supply power to various electronic components of the implant. For example, the local voltage V_CCmay supply power to the current path formed partially by the first and second pull up

resistors

1874 and1875. Generally, the local voltage V_CCmay be less than the DC input voltage V_INand the predefined threshold voltage, which may be approximated by the breakdown voltage V_BDof theZener diode1862.

When the regulation signal voltage level V_Ris less than the threshold voltage of thetransistor1876, there may be little or no regulation current I_Rbecause thetransistor1876 is not conducting. As such, the regulation voltage V_REGmay be substantially equal to the local voltage V_CC

However, when the DC input voltage V_INexceeds the breakdown voltage V_BDof theZener diode1862, the regulation signal voltage level V_Rmay begin to rise, and eventually, it may overcome the threshold voltage of thetransistor1876. As a result, thetransistor1876 may be turned on and draw the regulation current I_R. The regulation current I_Rmay cause a potential drop across the first pull upresistor1874, which is connected between the first node and a second node (e.g., the V_REGnode). Consequently, the regulation voltage V_REGmay decline as the regulation signal voltage level V_Rincrease. With the help of the pull upresistor1874, the regulation current I_Rcreates a regulation margin (i.e., potential difference) between the V_CCnode and the V_REGnode.

From the point where thetransistor1876 begins to conduct to the point where thetransistor1876 becomes saturated, the regulation voltage V_REGmay achieve substantial linearity with the regulation signal voltage V_R, which may be driven primarily by the breakdown current I_BR. As such, theregulation device1370 may perform the power regulation task when the DC input voltage V_INexceeds the breakdown voltage V_BDby a regulation margin. The regulation margin may be represented by the voltage level V_Rof theregulation signal1362. In one embodiment, for example, the regulation margin may range from about 0.05 V to about 10V. In another embodiment, for example, the regulation margin may range from about 0.1 V to about 5V. In yet another embodiment, for example, the regulation margin may range from about 1 V to about 3 V.

Thetransistor1876 may amplify the regulation margin between the DC input voltage and the predefined threshold. As such, the potential difference between the local voltage V_CCand the regulation voltage V_REGmay be highly responsive and sensitive to any slight change in the regulation margin.

After the regulation voltage V_REGbegins to decline, theimpedance switching device1380 may be activated. Generally, theimpedance switching device1380 may include a frequency modulation device (block)1820, aswitch1840, and animpedance component1844. The frequency modulation device1880 may generate afrequency modulation signal1822. Thefrequency modulation signal1822 may have a modulated frequency that is based on and/or represent the value of the regulation voltage V_REG. In one embodiment, for example, the modulated frequency of thefrequency modulation signal1822 may be directly proportional to the potential difference between the local voltage V_CCand the regulation voltage V_REG. In another embodiment, for example, the modulated frequency of thefrequency modulation signal1822 may be inversely proportional to the potential difference between the local voltage V_CCand the regulation voltage V_REG. In any event, the feedback signal as discussed inFIG. 13 may include thefrequency modulation signal1822.

Thefrequency modulation signal1822 may be used for turning on and off theswitch1840. According to the modulated frequency of thefrequency modulation signal1822, theimpedance component1844 may be periodically connected to and disconnected from the DC input voltage (V_IN) node. Theimpedance component1844 may act as an additional load and in the form of a pull down device. Because additional switching current I_Zis sunk by theimpedance component1844, the DC input voltage V_INmay drop and rise at the modulated frequency of thefrequency modulation signal1822.

As a result, the profile of the DC input voltage V_INmay be superimposed by the profile of thefrequency modulation signal1822. The superimposed V_INprofile may become a modulated amplitude (e.g., the message envelop) of thepassive telemetric signal1357. As a result, theswitch1840 may transform thefrequency modulation signal1822 to a frequency modulated amplitude modulated signal, such as thepassive telemetric signal1357. Thepassive telemetric signal1357 may be received and demodulated by the RF Board as part of the power regulation process.

Referring toFIG. 19, various waveforms of the implantpower regulation subsystem1800 are shown according to an embodiment of the present invention. Initially, the voltage across the Zener diode1862 (V_ZENER) may increase linearly and track the DC input voltage V_INwhen the DC input voltage V_INis less than the breakdown voltage V_BD. As such, the breakdown current I_BDmay be kept at minimum and the regulation signal voltage level V_Rmay be close to ground.

Because the regulation signal voltage level V_Rdoes not overcome the threshold voltage of thetransistor1876, there may be minimum or no regulation current I_Rflowing through the first and second pull down

resistors

1874 and1875. As a result, the regulation voltage V_REGmay track closely to the local voltage V_CC. Since V_CCmay be set a voltage level (e.g. 5 V) lower than the breakdown voltage V_BD(e.g. 5.6 V), the regulation voltage VREG may be saturated before the regulation mechanism is triggered. At this stage, theimpedance component1844 may be decoupled from the V_INnode, such that only minimum or no switching current I_Zmay be sunk from the V_INnode.

When the DC input voltage V_INbegins to exceed the breakdown voltage V_BD, theZener diode1862 may begin to conduct the breakdown current I_BD. As a result, the regulation signal voltage level V_Rmay begin to rise and it may eventually overcome the threshold voltage of thetransistor1876. From the point when thetransistor1876 begins to conduct the regulation current I_Rto the point when thetransistor1876 becomes saturated (i.e. maximum I_R), thepower regulation subsystem1800 may be under rapid regulation. That is, the regulation voltage V_REGmay be highly sensitive to the slightest increase in the DC input voltage V_IN.

As the regulation current I_Rincreases, the regulation voltage V_REGmay begin to decline, which may cause thefrequency modulation device1820 to generate thefrequency modulation signal1822. Driven by thefrequency modulation signal1822, theswitch1840 may cause theimpedance component1844 to be coupled to or decoupled from the V_INnode. Accordingly, the switching current I_Zmay share the frequency of thefrequency modulation signal1840. As discussed earlier, the frequency of thefrequency modulation signal1840 may be inversely proportional to the difference between the local voltage V_CCand the regulation voltage V_REG. Hence, the frequency of thefrequency modulation signal1840, which may be represented by the profile of the switching current I_Z, may decrease as regulation voltage VREG drops further away from local voltage V_CC.

The discussion now turns to a double modulation scheme adopted by the Implant in providing feedback information to the RF Board. The feedback information may include the value of the regulation voltage V_REGand/or the patient's biometrics data. Generally, the Implant may include a memory device for storing the patient's biometrics data, such as the patient's identity and event records pertinent to the patient's gastric band adjustment history. Among other information, each of the event records may record the current gastric band position and the adjustment date. It is desirable that the Implant may telemetrically transmit various pieces of feedback information in a compact and efficient manner.

InFIG. 20, waveforms of a double modulation (frequency modulated amplitude modulation) scheme are shown according to an embodiment of the present invention. Initially, there may be adata signal2010 to be transmitted from the Implant to the RF Board. The data signal2010 may have ahigh state2012 and alow state2014, each of which may represent one of the binary states. For example, the data signal2010 may have thehigh state2012 during time period (TP)1, thelow state2014 duringTP2, thehigh state2012 during bothTP3 andTP4, and thelow state2014 duringTP5.

Next, a frequency modulation may be applied to thedigital signal2010 to form afrequency modulation signal2020. Generally, the frequency modulation may be performed by thefrequency modulation device1820 or any other similar devices, such as a LTC6900 chip. Thefrequency modulation signal2020 may have one or more modulated frequencies, such as a first (low)frequency2022 and a second (high)frequency2024. Depending on the assignment scheme, the first and

second frequencies

2022 and2024 may be assigned to one of thelow state2012 or thehigh state2024 of the data signal2010.

In the present case, for example, thefirst frequency2022 may be assigned to thehigh state2012, and thesecond frequency2024 may be assigned to thelow state2024. Accordingly, thefrequency modulation signal2020 may have thefirst frequency2022 duringTP1, thesecond frequency2024 duringTP2, thefirst frequency2022 duringTP3 andTP4, and thesecond frequency2022 duringTP5.

Thefrequency modulation signal2020 may be used for encoding two or more signals simultaneously. In one embodiment, for example, thefrequency modulation signal2020 may be used for encoding two digital signals with four logic states. As such, thefrequency modulation signal2020 may have four frequency levels assigned to the four logic states. In another embodiment, for example, thefrequency modulation signal2020 may be used for encoding three digital signals with eight logic states. Accordingly, thefrequency modulation signal2020 may have eight frequency levels assigned to the eight logic states.

In yet another embodiment, for example, thefrequency modulation signal2020 may be used for encoding one digital signal and one analog signal. The digital signal may carry feedback information regarding the patient's biometrics. The analog signal may carry feedback information regarding the value of the regulation voltage V_REG. Accordingly, thefrequency modulation signal2020 may have a first frequency band and a second frequency band. Particularly, the high state of the digital signal and the spectrum of the analog signal may be jointly represented by the first frequency band, while the low state of the digital signal and the spectrum of the analog signal may be jointly represented by the second frequency band.

After thefrequency modulation signal2020 is generated, it may be combined, mixed, or superimposed with the original amplitude modulated carrier to form a frequency modulatedamplitude modulation signal2030. The original amplitude modulated carrier may be originated from the RF Board, and it may retain its carrier frequency at the implant antenna. As such, the frequency modulatedamplitude modulation signal2030 may have a common carrier frequency and a message frequency. The common carrier frequency may be constant throughout the entire transmission period, while the message (envelop) frequency may track closely to the first and

second frequencies

2022 and2024 of thefrequency modulation signal2020. Accordingly, the frequency modulatedamplitude modulation signal2030 may have a first message(envelop)frequency2032 duringTP1, a second message (envelop)frequency2034 duringTP2, and thefirst message frequency2032 duringTP3.

Using the frequency modulatedamplitude modulation signal2030 to provide feedback information may provide several advantages. For example, the transmission of the frequency modulatedamplitude modulation signal2030 may consume very little energy from the Implant because it may take advantage of the original amplitude modulation signal and it may be passively transmitted. For another example, the intermediate frequency modulation scheme may allow multiple pieces of information to be transmitted simultaneously, thereby increasing the transmission efficiency and shortening the total transmission time. For another example, the frequency modulatedamplitude modulation signal2030 may only require one communication channel. As such, the external antenna and the implant antenna may be transferring power and communicating at the same time. For yet another example, the frequency modulatedamplitude modulation signal2030 may have a high tolerance to parasitic noise. Mainly, the underlying information may be encoded in different frequency levels and/or frequency bands, which may be highly resistive to distortion caused by parasitic noise.

FIG. 21 shows a schematic view of adouble modulation subsystem2100 according to an embodiment of the present invention. Generally, thedouble modulation subsystem2100 may help generate the feedback signal for communicating the value of the regulation voltage V_REGto the RF Board. As such, thedouble modulation subsystem2100 may be used as a communication system and in conjunction with thepower regulation subsystem1800.

Thedouble modulation subsystem2100 may include afrequency modulation device2120, anoutput transistor2150, adata switch2112, a voltage regulation resistor R_REG, a data resistor R_CMD, and a bias resistor R_BO. Thefrequency modulation device2120 may have similar functional features as thefrequency modulation device1820. Moreover, thefrequency modulation device2120 may adjust a switching frequency (f_SW) of the frequency modulatedsignal1822 according to the regulation voltage and the status of thedata switch2112.

The data switch2112 may be used for generating serial data signals similar to the data signal2010 as shown inFIG. 20. More specifically, the data switch2112 may be controlled by the implant microcontroller476 (previously shown inFIG. 4), which may encode various information to the data signal. In one embodiment, for example, the implant microcontroller may encode the patient's identification information to the data signal. In another embodiment, for example, the implant microcontroller may encode the patient's gastric band adjustment record to the data signal. In yet another embodiment, for example, the implant microcontroller may encode a handshake confirmation message to the data signal.

Thefrequency modulation device2120 may be implemented by a LTC 6900 chip or other equivalent devices. From a functional standpoint, thefrequency modulation device2120 may determine the switching frequency according to the local voltage V_CC, a set voltage V_SETand an input current I_RES. Similar to the power system as shown inFIG. 18, the regulation voltage V_REGmay be generated by theregulation device1370 at a first node (e.g., the V_REGnode). The set voltage V_SETat a second node (e.g., the V_SETnode) may be controlled by a data path, which may include thedata switch2112 and the command resistor R_CMD. Moreover, thevoltage regulator1872 may generate the local voltage V_CCat a third node (e.g., the V_CCnode). The local voltage V_CCmay perform as a current source for the pull upresistor1874 and the data path.

In one embodiment, thefrequency modulation device2120 may include adifferential amplifier2132, apass transistor2134, and anoscillator2140. Thedifferential amplifier2132 may generate an input differential voltage V_DIFFby amplifying the potential difference between the local voltage V_CCand a set voltage V_SET(i.e. V_CC−V_SET). Thepass transistor2134 may be biased by a bias voltage V_BIASto pass the input current I_RESfrom the V_SETnode to theoscillator2140. After receiving the input differential voltage V_DIFFand the input current I_RES, theoscillator2140 may generate thefrequency modulation signal1822 with the switching frequency f_SW, which may be modeled by Equation 1:

f_{sw} = 1 MHz \times 20 k Ω \times \frac{I_{RES}}{(V_{CC} - V_{SET})} .

Generally, the input current I_RESmay be a summation of several currents joining at the V_SETnode. For example, when thedata switch2112 is closed, it may conduct a data current (I_CMD) from the V_CCnode to the V_SETnode. The data current I_CMDmay be characterized as (V_CC−V_SET)/R_REG. For another example, a regulation current I_REGmay be conducted across the regulation resistor R_REG. The magnitude of the regulation current I_REGmay depend on the level of regulation, such that it may range from (V_CC−V_SET)/R_REGto about 0.5*(V_CC−V_SET)/R_REG. For yet another example, a bias current I_BOmay be conducted across the bias resistor R_BO, and it may be characterized as (V_CC−V_SET)/R_BO.

When the data signal is at a low state (i.e.data switch2112 closed) and when there is no power regulation, the switching frequency may be modeled byEquation 2, which recites:

f_{SW, LL, NR} = 1 MHz \times 20 k Ω \times (\frac{1}{R_{BO}} + \frac{1}{R_{REG}} + \frac{1}{R_{CMD}}) .

When the data signal is at a high state (i.e.data switch2112 open) and when there is no power regulation, the switching frequency may be modeled byEquation 3, which recites:

f_{SW, HL, NR} = 1 MHz \times 20 k Ω \times (\frac{1}{R_{BO}} + \frac{1}{R_{REG}}) .

When the data signal is at a low state and when there is maximum power regulation, the switching frequency may be modeled byEquation 4, which recites:

f_{SW, LL, MR} = f_{SW, LL, NR} - 1 MHz \times 10 k Ω \times (\frac{V_{CC}}{R_{REG} \times (V_{CC} - V_{SET})}) .

When the data signal is at a high state and when there is maximum power regulation, the switching frequency may be modeled byEquation 5, which recites:

f_{SW, HL, MR} = f_{SW, HL, NR} - 1 MHz \times 10 k Ω \times (\frac{V_{CC}}{R_{REG} \times (V_{CC} - V_{SET})}) .

When the data signal is at a low state and when the regulation voltage is at V_REG, the switching frequency may be modeled byEquation 6, which recites:

f_{SW, LL, VR} = f_{SW, LL, NR} - 1 MHz \times 20 k Ω \times (\frac{V_{CC} - V_{REG}}{R_{REG} \times (V_{CC} - V_{SET})}) .

For low output level and regulation voltage at V_REG, the switching frequency may be modeled byEquation 7, which recites:

f_{SW, HL, VR} = f_{SW, HL, NR} - 1 MHz \times 20 k Ω \times (\frac{V_{CC} - V_{REG}}{R_{REG} \times (V_{CC} - V_{SET})}) .

As persons skilled in the art may readily appreciate, the value of the swing frequency f_SWmay depend on the resistances of the various resistors, which may be adjusted to meet various design goals. In one embodiment, for example, the resistance of the bias resistor R_BOmay be about 29.43 kΩ. In another embodiment, for example, the resistance of the regulation resistor R_REGmay be about 1 MΩ. In yet another embodiment, for example, the resist R_CMDmay be about 430 kΩ. Moreover, V_CCmay be set at about 5V, such that V_SETmay be at about 3.9V.

Accordingly, the swing frequency f_SW,LL,NRmay be about 746 kHz, the swing frequency f_SW,HL,NRmay be about 699.5 kHz, the swing frequency f_SW,LL,MRmay be about 700.5 kHz, and the swing frequency f_SW,HL,MRmay be about 654 kHz. Furthermore, the swing frequency f_SW,LL,VRmay range from about 746 kHz to about 700.5 kHz, while the swing frequency f_SW,HL,VRmay range from about 699.5 kHz to about 654 kHz.

Referring toFIG. 22, a frequency chart of the double modulation scheme is shown according to the above parameters. With a binary data signal, the double modulation scheme may include alow state band2202 and ahigh state band2204. Thelow state band2202 may represent the range of swing frequencies that may be assigned to the low state value of the data signal. Similarly, thehigh state band2204 may represent the range of swing frequencies that may be assigned to the high state value of the data signal. Because the swing frequency may incorporate or embedded with power regulation information, each of the low and

high state bands

2202 and2204 may have a maximum swing frequency (i.e. f_SW,LL,NRand f_SW,HL,NR) for representing a no-regulation scenario, a transient swing frequency (i.e. f_SW,LL,VRand f_SW,HL,VR) for representing a rapid regulation scenario, and a minimum swing frequency (i.e. f_SW,LL,MRand f_SW,HL,RM) for representing a maximum-regulation scenario.

AlthoughFIG. 22 shows only two swing frequency bands, thefrequency modulation device2100 may provide two or more swing frequency bands. In one embodiment, for example, thefrequency modulation device2100 may provide four swing frequency bands for encoding two binary data signals. In another embodiment, for example, thefrequency modulation device2100 may provide eight swing frequency bands for encoding three binary data signals. In yet another embodiment, for example, thefrequency modulation device2100 may provide sixteen swing frequency bands for encoding four binary data signals.

The discussion now turns to the demodulation scheme and the demodulation device used for decoding the feedback signals from the Implant.FIG. 23A shows a frequency spectrum of the frequency modulation feedback signal according to an embodiment of the present invention. Generally, the frequency modulation feedback signal may occupy one of thelow state band2202 or thehigh state band2204 to transmit a single binary bit of data. However, the frequency modulation feedback signal may shift from a higher end of the band to a lower end of the band as the regulation voltage V_REGof the implant increases. Such intra-band frequency shift may occur during the transmission of the single binary bit of data. Advantageously, the RF Board may be able to regulate the power within the Implant in real time, so that the regulation process may be independent of the data transmission process.

FIG. 23B shows ademodulation2300 of the frequency modulated amplitude modulation signal according to an embodiment of the present invention. Generally, the demodulation signal may map a low frequency band to a high voltage state, and it may map a high frequency band to a low voltage state. Moreover, the demodulation signal may have a first DC level2310 when the implant requests no regulation, and it may have a second DC level2330 when the Implant requests power reduction (or power regulation). Accordingly, apotential difference2320 between the first andsecond DC levels2310 and2320 may correspond to the level of power reduction requested by the Implant.

FIG. 23B shows that the maximum regulation demodulation signal may overlap with the no regulation demodulation signal. However, in an alternative embodiment, the maximum regulation demodulation signal and the no regulation demodulation signal may occupy non-overlapping voltage ranges.

Referring toFIG. 24, a schematic view of ademodulation device2400 is shown according to an embodiment of the present invention. Generally, thedemodulation device2400 may implement the functional features of thedemodulation device1330 as discussed inFIG. 13. Particularly, thedemodulation device2400 may include ademodulation processor2410, alow pass filter2420, a signalstrength amplifying stage2422, adata amplifying stage2432, a three-stage powercontrol amplifying stage2440, and apower override device2450.

Thedemodulation processor2410 may be used for processing the signal ANT_RX, which may be received and extracted from the external antenna. The signalstrength amplifying stage2422 may receive the processed signal and generate a signal strength indicator signal RSSI. Generally, the signal strength indicator signal RSSI may indicate the strength of the telemetric coupling between the external antenna and the implant antenna.

Thelow pass filter2420 may be used for filtering out the high frequency component of the processed signal. As such, the carrier frequency may be eliminated, and the frequency modulated feedback signal may be further processed. Next, thedata amplifying stage2432 may receive the filtered signal and generate a data signal RF_RX according to the state band of the filtered signal. Simultaneously, the three-stage powercontrol amplifying stage2440 may receive the filtered signal and generate a voltage supply control signal VSUP_CTRL according to the frequency shift caused by the regulation voltage VREG.

Accordingly, the power supply device1340 (previously shown inFIG. 13) may use the voltage supply control signal VSUP_CTRL to adjust theRF supply voltage1342. Because themodulation device1320 may be powered by theRF supply voltage1342, the amplitude component of the amplitude modulation signal may be controlled indirectly by theRF supply voltage1342. As a result, the power transmission may be regulated by reducing the amplitude component of the amplitude modulation signal.

Additionally, the three-stage power control amplifying stage may include asecond stage2444 for generating a regulation level signal REG_LEVEL, which may indicate the level of regulation requested by the Implant. Generally, the level of regulation may be higher when the Implant's DC input voltage VIN is much higher than the breakdown voltage VBD. Alternatively, the level of regulation may be lower when the Implant's DC input voltage VIN is below or slightly above the breakdown voltage VBD.

FIG. 25 shows the relationship among various output signals of the demodulation device and a transmission distance separating the external antenna and the implant antenna. Generally, as the transmission distance increases, the signal strength indicator signal RSSI and the regulation level signal REG_LEVEL may increase. As such, the RF voltage supply VSUP may decrease to reduce the power transmission to the Implant. As shown inFIG. 25, the RF Board and the Implant may undergo rapid power regulation when the transmission distance ranges from 30 mm to about 40 mm. Moreover, the RF Board and the Implant may undergo maximum power regulation when the transmission distance is below 20 mm.

According to an embodiment of the present invention and referring again toFIG. 11, the FM demodulator in theRF demodulator block1108 may generate a received signal strength indicator (RSSI), a REG_LEVEL signal and a VSUP_CTRL signal. Ultimately the VSUP_CTRL signal controls the output voltage VSUP.FIG. 25 shows some examplary results of the RSSI signal, the REG_LEVEL signal, and the output voltage VSUP at various transmission distances.

The discussion now turns to the software algorithms implemented in the HID subsystem and the RF subsystem.FIG. 26 shows thecommunication protocol UART2600 among the HID subsystem, RF subsystem, and the implant according to an embodiment of the present invention. Generally, theHID microcontroller2622 may function as the master device within the control device (control unit)2620 and it may control most user interfaces, such as the display device, the buttons, the audio output device (e.g., speaker), and the memory devices. TheHID microcontroller2622 may sendcommand message2602 to theRF microcontroller2624, and request theRF microcontroller2624 to perform several functions.

TheRF microcontroller2624 may perform as a slave to theHID microcontroller2622. Nevertheless, theRF microcontroller2624 may sendnotification messages2604 to theHID microcontroller2622 even without being requested. TheRF microcontroller2626 may control the power induction process in the implant, the charging circuit in the docking station, the communication to and from the implant, and the communication with theHID microcontroller2622. The GND-GND link2608 may provide the “0 Volt” reference for all other signals. The RTS-CTS link2606 may be a flux control line, which may be used for stopping the incoming flux of data from the HID sub-system when the RF sub-system is not ready to accept them.

FIG. 27 shows the state diagram of theHID subsystem algorithm2700 according to an embodiment of the present invention. Each state and transition will be discussed in detail in conjunction withFIGS. 8A-8R, which shows various screen shots of the control device. Generally, there may be five major blocks of states, including the power offblock2710, the active or power onblock2720, thecharge block2750, theerror block2760, and thewarning block2770.

The transition from the power offblock2710 to the power onblock2720 may be triggered by pressing the power on button on thecontrol device110 as shown inFIGS. 5A and 5B. Similarly, the transition from the power onblock2720 to the power offblock2710 may be triggered by pressing the power off button or after a 10-minute time out delay since a user has not interacted with the HID subsystem.

Generally, any state within the power onblock2720 may transit to thewarning block2770 and/or theerror block2760. To exit thewarning block2770 and/or theerror block2760, the user may enter the power offblock2710 by pressing the power off button or waiting for the 10-minute time out delay.

Thecharge block2750 may be entered when the control device is connected to the docking station during the active mode. Once the control device is disconnected from the docking station, thecharge block2750 may return to a previous state of the power onblock2720. Normally, the returned state may be a state from which thecharge block2750 is transited initially.

As the power onblock2720 is initiated, theINIT state2722 may initialize the HID subsystem, display the welcome screen, and load the code entry screen. After that, the ASKING FORCODE state2724 may be entered. The ASKING FORCODE state2724 may repeat itself until a correct 4-digit pass code is received, upon which theSEARCHING state2726 may be entered. Once the external antenna is positioned close enough to the implant to establish a sufficient good telemetric (or electromagnetic) coupling, which may be represented by three out of five search bars in the searching screen, theUPLOADING state2728 may be initiated.

In theUPLOADING state2728, the loading start screen may be displayed, followed by the loading end screen. Moreover, the implant is powered up and the communication with the implant is initiated. If, at any point of theUPLOADING state2728, the telemetric coupling deteriorates and becomes insufficient, the HID subsystem may return to theSEARCHING state2726. Otherwise, the patient information is uploaded from the implant such that theSTANDBY state2730 may be initiated.

TheSTANDBY state2730 may lead to several states depending on the triggering conditions. For example, if the magnetic coupling deteriorates and becomes insufficient, the HID subsystem may return to theSEARCHING state2726. For another example, if the Locked key is pressed, the HID subsystem may enter the LOCKEDstate2732 in which the locked screen may be displayed, and from which any key may be pressed to return to the ASKING FORCODE state2724.

For yet another example, if the code-change auxiliary key is pressed, the HID subsystem may enter the ASKING FOROLD CODE state2734 in which the enter-old-code screen may be displayed. Once the correct 4-digit code is received and the Next auxiliary key is pressed, the ASKING FORNEW CODE state2736 may be entered, in which the enter-new-code screen may be displayed. After receiving the new 4-digit code, the HID subsystem may enter the CONFIRMNEW CODE state2738, in which the confirm-or-cancel-code screen may be displayed and the user may elect to either confirm or cancel the entered code. If the user presses the OK auxiliary key to confirm the entered code, the code changed screen may be displayed and the HID subsystem may return to theSTANDBY state2730; otherwise, if the user presses the Cancel auxiliary key to cancel the entered new code, the HID subsystem may simply return to theSTANDBY state2730.

While in theSTANDBY state2730, the user may request a graph of the patient's gastric band adjustment history by pressing the Chart auxiliary key. Accordingly, theGRAPH state2740 may be entered, and the history plot screen may be displayed. From theGRAPH state2740, the HID subsystem may enter theLIST state2742 if the user presses the List auxiliary key, thereby loading the history list screen. After reviewing the history plot screen and/or the history list screen, the user may press the Return key to return to theSTANDBY state2730.

Moreover, the user may adjust the width of the gastric band from theSTANDBY state2730. For example, when the Open button is pressed, the HID subsystem may enter theMOVE IMPLANT state2744, in which the opening screen may be displayed. Accordingly, the implant motor may drive the gastric band to expand its diameter. For another example, when the Close button is pressed, the HID subsystem may initiate theMOVE IMPLANT state2744, in which the closing screen may be displayed. Accordingly, the implant motor may drive the gastric band to constrict its diameter.

In order to achieve a desirable gastric band diameter, the user may repeat the above process either by pressing the Open button or Close button repeatedly, or by pressing the Open button and the Close button alternately. During theMOVE IMPLANT state2744, if the implant motor is blocked and such blockage is detected, the HID subsystem may return to theSTANDBY state2730. Moreover, during theMOVE IMPLANT state2744, if the magnetic coupling deteriorates and becomes insufficient, the HID subsystem may return to theSEARCHING state2726.

When the control device is connected to the docking station, theCHARGE block2750 may be entered, during which the battery recharging may be performed and the battery recharging screen may be displayed. In theCHARGE block2750, the initial state is theFAST CHARGE state2752, during which the recharging process is controlled by current. Once the fast charging is complete, theNORMAL CHARGE state2754 may be entered, and the battery recharging process may be controlled by voltage. Once the battery is fully charged, the HID subsystem may enter theFULL CHARGE state2756. The HID subsystem may alternate between theNORMAL CHARGE state2754 and theFULL CHARGE state2756 if the control device remained connected to the docking station long enough for the battery to dissipate some of the charges.

The discussion now turns to the RF subsystem algorithm.FIG. 28 shows the state diagram of anRF subsystem algorithm2800 according to an embodiment of the present invention. The RF subsystem powers and communicates with the implant, such that it may manage the implant's telemetric (electromagnetic) coupling, control the implant's power consumption, count the motor steps, and receive feedback information from the implant. The RF subsystem may also communicate with the HID subsystem, monitor battery recharging, respond errors and interrupts, and perform cyclic redundant check (CRC), delay, filtering and driving.

As shown inFIG. 28, the RF module cycles among four different states, each of them may last about 500 μs. The first state may be theHID Communication state2810, in which the RF subsystem may receive up to two commands from the HID subsystem. In response, the RF subsystem may respond to these commands by sending up to eight notification messages. The second state may be theRF Power state2820, in which the power level to the implant may be monitored and controlled. The third state may be theImplant Communication state2830, in which data may be sent to and/or received from the implant. The received data may be further analyzed in this state. The fourth state may be theBattery Charger state2840, in which battery power may be monitored and controlled if the control device (control device) is properly connected to the docking station. Generally, the RF subsystem may cycle or return back to theHID Communication state2810 after completing theBattery Charger state2840.

Referring again toFIG. 26, theHID microcontroller2622 may interact with theRF microcontroller2624 through aUART interface2600. Generally, the HID microcontroller2622 (master) may send up to two commands consecutively. The HID microcontroller2622 (master) may demand answer messages from the RF microcontroller2624 (slave). In response, the slave may send up to eight notifications consecutively to the master. According to an embodiment of the present invention, Table 2 below shows the data structures for the command, the answer message and the notification message.

TABLE 2

Data structures of the command message, the
answer message, and the notification message.

HEADER

DATA

CRC

CODE	SEQ	LENGTH	DATA[0]	. . .	DATA[Length-1]	CRC

COMMAND FROM MASTER (HID)

16-bit

. . .

16-bit

ANSWER MESSAGE FROM SLAVE (RF)

NOTIFICATION MESSAGE FROM SLAVE (RF)

0x4154	16-bit	16-bit	16-bit	. . .	16-bit	16-bit

These command and messages may share a similar data structure, which may includes a six-byte header followed by a 2*LENGTH-byte long data field and a two-byte CRC code. As discussed herein, LENGTH may be a predefined parameter specifying the length of the data. Within the six-byte header, the first two bytes contain the command code, the next two bytes contain a sequence number, and the last two bytes describe the LENGTH of the following data field. The data field may be empty if LENGTH equals 0.

Generally, the HID master does not transmit all the header bytes at one time. In one embodiment, for example,FIG. 29A shows a command only communication protocol between the HID and RF subsystems. More particularly, the HID master may send a two-byte command code to the RF slave, which may respond by sending back an ACK message. Upon receiving the ACK message, the HID master may begin transmitting the Sequence bytes, the LENGTH bytes, and the CRC bytes according to the shown order.

In another embodiment, for example,FIG. 29B shows a command-data communication protocol between the HID and RF subsystems. The protocol illustrated inFIG. 29B may be similar to the protocol illustrated inFIG. 29A except that the Data bytes may be sent after the LENGTH bytes.

Next,FIG. 30 shows an answer message communication protocol from the RF subsystem according to an embodiment of the present invention. After receiving and processing the command message from the HID master, the RF slave may send back an answer message with data structure as shown in Table 2. Similarly,FIG. 31 shows that the RF slave may initiate notification message without receiving prior command from the HID master.

The discussion now turns to the features of the docking station.FIGS. 32A-32C show an exploded view, a front view and a back view of adocking station3200 according to an embodiment of the present invention. Generally, thedocking station3200 may include abottom shell3202, atop shell3204, fourrubber foot3206, aregulatory sticker3208, aballast 2 bottom3210, aballast 1 top3212, amagnet3214, twoalignment pins3216, amain PCB3218, and asupplementary PCB3220.

Thedocking station3200 may have asaddle structure3232, which may provide one or more contact point for coupling with the control device. Themain PCB3218 may be used for performing power protection to protect thedocking station3200 and the control device from the power surge of the power adapter. Moreover, themain PCB3218 may assist the RF subsystem in monitoring the charging status and the charging temperature.

FIG. 33 shows a schematic view of thedocking station subsystem3310 interacting with theRF Board3350 according to an embodiment of the present invention. Thedocking station system3310 may be implemented by the main PCB3218 (seeFIG. 32), and it may include atemperature measurement block3312, a powersupply management block3314, aprotection block3316, and ashunt resistance device3318. The powersupply management block3314 may interact with theRF board3350 to perform battery charging (charging status) management and charging temperature (overheat prevention) management.

Charging current may be estimated by measuring voltage across theshunt resistance device3318. In one embodiment, for example, theshunt resistance device3318 may have a resistance of about 0.015Ω. Moreover, there may be NTC thermistors inside the batteries for proper temperature measurement, as well as several polyswitches for resetting the circuit in case of power surges at the battery level.

FIG. 34 shows a fast charge mode voltage-current chart according to an embodiment of the present invention. At the beginning of the fast charge mode, the charging process is controlled through a constant current I_ch. According to an embodiment of the current invention, I_chmay be about 5 A. After the battery charge V_Breaches a certain voltage, it will decrease by ΔV and the charging circuit then switches to the normal charge mode.

The RF board may perform the charge monitoring. A dedicated NiMh charger chip (e.g., the LTC1759 chip) may be used for controlling the charging process. The LTC1759 chip may use temperature measurement of the battery pack to adjust its charging algorithm. The LTC1759 chip may be a high current DC-to-DC power supply controlled by a NiMH charger controller, both of which may be included in a single chip. Thus, the LTC1759 chip may control the power given to the battery pack and ensure that it complies with the charging profile as shown inFIG. 34.

The discussion now turns to the retractable external antenna (external antenna with retractable cable).FIGS. 35A-35B show a perspective view and an exploded view of an external antenna with retractable cable according to an embodiment of the present invention. Generally, the retractableexternal antenna3500 may include anantenna bottom3502, anantenna top3504, a windingdrum3506, agear wheel3508, abutton3510, abutton ring3512, ametal plate3514, aPCB3516, a tap3518, acompression spring3522, adrive spring3524, anantenna cable3526, agear wheel pin3528, acenter axis3530, a windingdrum lid3532, asound barrier3534, aglide plate3536, and aball bearing3538.

To achieve smooth retraction, the retractor components are placed inside of the windingdrum3506 while theantenna cable3526 retracts on the circumferential surface of the windingdrum3506. In order to enable proper power induction, the cable of the antenna may be fully deployed until a green marker can be seen. Otherwise, the coiled antenna cable may absorb excessive power induction energy. The retractable external antenna can be attached to the control device by pushing the connector against the control device until a “click” is heard, which signifies that the antenna cable3626 is locked. Once locked, the antenna cable3626 is in a suitable configuration. The locking mechanism ensures a good electromagnetic coupling by establishing a unique and stable resting position for the cable.

Thegear wheel3508 may include a small spring loaded pin (gear wheel pin)3528. Theantenna top3504 may have a small hole (not shown). The “click” sound may be produced when the spring loadedpin3528 enters into the small hole. This may occur when the spring loadedpin3528 is in front of the hole after theantenna cable3526 is fully unwound. When thebottom ring3512 is pressed, the spring loadedpin3528 may be disengaged, thereby releasing theantenna cable3526.

As shown inFIGS. 36A and 36B, the retractableexternal antenna3500 may be stored at the back of the control device according to an embodiment of the present invention. Themagnetic pins3606 of the control device provide easy connection points for connecting to the docking station.

The discussion now turns to various structural and functional features of the implant. Referring toFIGS. 37A-37B, a perspective view and an exploded view of the implant3700 (e.g., a gastric band system) are shown according to an embodiment of the present invention. Generally, theimplant3700 may include amembrane shell3702, adorsal element3704, amotor sleeve3706, an implant electronic device enclosure (protection case) base andcable sleeve3708, amanipulation handle3710, acable sleeve3712, a skeleton3714, an implant electronic device enclosure (protection case)cover3716, a motor andcable assembly3718, aflexible screw assembly3720, an implantelectronic device PCB3722, and a stabilizingtube3724.

Thedorsal element3704 may have a first end, a second end, and a curvy semi-tubular body connecting the first and second ends. The first end of thedorsal element3704 may have a flange lock and a first opening, while the second end of thedorsal element3704 may have an open compartment.

The stabilizingtube3724 may be inserted into the ladder body of the skeleton3714, such that it may be used for filling in the space defined by the ladder body and for stabilizing the ladder structure.

Themotor assembly3718 may have a motor coupled to a motor cable. The motor may be arranged to receive and maneuver theflexible screw assembly3720. For example, the motor may have one or more set of rotors and/or gears for engaging a threaded section of theflexible screw assembly3720. The motor may move a crimped end of theflexible screw assembly3720 towards or away from the motor.

Theflexible screw assembly3720 may have a hooked end, which may be guided through a center conduit (space) of the stabilizingtube3724. Because the stabilizingtube3724 is adapted to the curvy shape of thedorsal element3704, theflexible screw assembly3720 may be bended with the stabilizingtube3724. After leaving the stabilizingtube3724, the hook end of theflexible screw assembly3720 may be secured to the distal end of the skeleton, which may be secured to the first end of the dorsal element.

Next, the motor of themotor assembly3718 may engage theflexible screw assembly3720. The flexible screw assembly may have an inner section that is inserted into the stabilizingtube3724. Also, theflexible screw assembly3720 may have an outer section that stays outside of the stabilizingtube3724 and extends beyond the open compartments of the skeleton3714 and of thedorsal element3704. The motor of themotor assembly3718 may then engage the threaded section of theflexible screw assembly3720, and move the crimped end of theflexible screw assembly3720 away from the motor.

The membrane shell3102 may have a tubular body, which may be used for covering the semi-tubular body of thedorsal element3704. Thecable sleeve3712 may be used for covering and protecting the motor cable, and themotor sleeve3706 may be used for covering and protecting the motor.

The open end of the motor cable may be soldered onto the implantelectronic device PCB3722, which may be protected by theenclosure cover3716 and theenclosure base3708. The flange of themanipulation handle3710 may be inserted through the hole of the implant electronic device enclosure, folded over, and secured to the implant electronic device enclosure by applying an appropriate amount of MED2-4213 silicon glue or the equivalent thereof on the flange and the cavity of themanipulation handle3710. The tapered end of the manipulation handle may be inserted and guided through the opening located at the first end of thedorsal element3704, thereby leading the second end of thedorsal element3704 to be inserted into the first end of thedorsal element3704.

Consequently, thedorsal element3704, and themembrane shell3702, may form a ring structure. Particularly, the ring structure may have an adjustable ventral (inner) ring surface and a rigid dorsal (outer) ring surface. The adjustable ventral ring surface may be equipped with several cushion members for applying pressure against the stomach of a patient.

As persons skilled in the art may readily appreciate, an appropriate amount of MED2-4213 silicon glue, or the equivalence thereof, may be applied to various components, and the various junctions of thereof, of theimplant3700 for strengthening the overall structure of theimplant3700.

The discussion now turns to the implant electronic device protection case (enclosure) components. Generally, the implantelectronic device PCB3722 may be coupled to the motor cable, such that the implantelectronic device PCB3722 may send control signals to the motor and sense a motor coil current of the motor. The implantelectronic device PCB3722, and the junction at which the implant electronic device is coupled to the motor cable, may be protected by the implant electronic device enclosure, which may include theenclosure cover3716, theenclosure base3708, and thestrain relieving sheath3850.

FIGS. 38A and 38B shows a top perspective view and a bottom perspective view of anenclosure base shell3810 according to an embodiment of the present invention. Generally, theenclosure base shell3810 may be part of theenclosure base3708. Particularly, theenclosure base shell3810 may include acompartment3814 for fitting theelectronic device PCB3722, acable port3812 for receiving and guiding the motor cable, and ahandle hinge3816 for receiving the flange of themanipulation handle3710.

Referring toFIG. 38C, a perspective view of acladding3820 is shown according to an embodiment of the present invention. Generally, thecladding3820 may be part of theenclosure cover3716. Particularly, thecladding3820 may be coupled to and cooperate with theenclosure base shell3810 for guiding and protecting the motor cable. Thecladding3820 may include a plurality of openings to allow silicon material to be overmolded therein.

Referring toFIG. 38D, a perspective view of anenclosure cover shell3830 is shown according to an embodiment of the present invention. Generally, theenclosure cover shell3830 may be part of theenclosure cover3716. Theenclosure cover shell3830 may be detachably coupled to theenclosure base shell3810 and thecladding3820 to form the enclosure case. The enclosure case may provide stability and protection for the implantelectronic device PCB3722 and for the connection established between the implantelectronic device PCB3722 and the motor cable.

Referring toFIG. 38E, thestrain relieving sheath3850 may be used for providing flexible support for the motor cable around thecable port3812 area. Thestrain relieving sheath3850 may help prevent breakage of the motor cable by restraining the motion of the motor cable around thecable port3812 area. Referring toFIG. 38F, the extremity of thestrain relieving sheath3850 may have a silicone-PEEK overmolding and a plurality ofinternal bumps3852 for keeping thecladding3820 centered and for distributing the glue evenly.

The discussion now turns to the implantelectronic device PCB3722.FIGS. 39A-39B show a top view and a bottom view of an implant electronic system board (PCB)3900, which may be used for implementing the functional features of the implantelectronic device PCB3722. Referring toFIG. 39A, thePCB3900 may include a powerregulation subsystem circuitry3901, amicroprocessor3902, and animplant antenna3904. The implant (internal)antenna3904 may loop around the periphery of thePCB3900, and it may be responsible for receiving the RF signals transmitted from the external antenna of the control device.

The powerregulation subsystem circuitry3904 may be coupled to theimplant antenna3904 via theL2 connection port3906. The powerregulation subsystem circuitry3901 may include apower regulator3908 for maintaining the local voltage V_cc. Moreover, the powerregulation subsystem circuitry3904 may receive the induced power and generate the power regulation signals when the DC input voltage V_INis above certain predetermined threshold (e.g. 5.6 V).

Themicroprocessor3902 may be coupled to the powerregulation subsystem circuitry3901. Themicroprocessor3902 may be coupled with theimplant antenna3904. Generally, themicroprocessor3902 may be used for generating frequency modulation signals, which may be embedded with power regulation information and gastric band adjustment history information.

Particularly, themicroprocessor3902 may be used for receiving and processing commands send from thecontrol device110 as shown inFIG. 1. For example, themicroprocessor3902 may receive a gastric band adjustment command from thecontrol device110. In response, themicroprocessor3902 may send motor step signal to the motor for adjusting the width of the gastric band.

Moreover, themicroprocessor3902 may receive a gastric band adjustment history request command from thecontrol device110. In, response, themicroprocessor3902 may retrieve the requested data from a memory device (not shown) and send the retrieved data back to the control device. In one embodiment, themicroprocessor3902 may have about 8 kB of programmable memory, 512 Bytes of data memory, 512 Bytes of SRAM, two timers, several input and out pins, one comparator, an A/D converter and several interrupt sources.

Referring toFIG. 39B, the bottom surface of the implantelectronic system board3900 may have nineoval connection pads3912, each of which may be soldered to one of nine motor wires of the motor cable. Among the nineovals connection pads3912, eight of them may be grouped in four parallel pairs to provide redundancy protection. The remaining oneoval connection pad3912 may be soldered to an FC wire. The largemetallic surface3914 may be soldered to a motor cable center ground wire (GND).

The discussion now turns to the structural and functional features of themanipulation handle3710.FIGS. 40A-40C show various views of amanipulation hand4000, which may be used for implementing the functional features of themanipulation handle3710. Generally, themanipulation hand4000 may have a taperedend4042, abase end4044, anelongated body4043 connecting thetapered end4042 and thebase end4044, and aflange4052 coupled to thebase end4044.

Theflange4052 may engage thehandle hinge3816 of the implantelectronic device enclosure3810. The profiled of theelongated body4043 may allow easier insertion into the opening of the dorsal element. Specifically, theelongated body4043 may have an increase thickness from thetapered end4042 to thebase end4044. Moreover, theelongated body4043 may havehelicoidal arrows4046, which may be used for indicating the direction for insertion. In one embodiment, thehelicoidal arrows4046 may form on one side of theelongated body4043. In another embodiment, thehelicoidal arrows4046 may form on both sides of theelongated body4043 as shown inFIG. 40C. Accordingly, thehelicoidal arrows4046 may be viewed at most angles during the implant procedure.

Referring toFIG. 40B, themanipulation handle4000 may have first, second, third and fourth widths. In one embodiment, for example, thefirst width4002 may be about 10.34 mm, thesecond width4004 may be about 17 mm, thethird width4006 may be about 3.33 mm, and thefourth width4008 may be about 4.2 mm.

Referring toFIG. 40C, themanipulation handle4000 may have aflange length4010 and a body length4038. In one embodiment, for example, theflange length4010 may be about 13.5 mm, and the body length4038 may be about 100.3 mm. Theflange4052 may have aflange thickness4012, which may be about 1.4 mm. Theelongated body4043 may have twelve thicknesses. In one embodiment, for example, thefirst thickness4014 may be about 4.96 mm, thesecond thickness4016 may be about 4.5 mm, thethird thickness4018 may be about 3.9 mm, thefourth thickness4020 may be about 3.6 mm, thefifth thickness4022 may be about 3.45 mm, thesixth thickness4024 may be about 3.42 mm, the seventhickness4026 may be about 3.4 mm, theeighth thickness4028 may be about 3.2 mm, theninth thickness4030 may be about 3.03 mm, thetenth thickness4032 may be about 2.9 mm, theeleventh thickness4034 may be about 2.8 mm, and thetwelfth thickness4036 may be about 1.7 mm.

The discussion now turns to the software algorithm of the implant electronic system. InFIG. 41, a state diagram of implant electronic device software algorithm is shown according to an embodiment of the present invention. Generally, the implant electronic device software algorithm may be executed by themicroprocessor3902 to perform various functions, such as driving the motor, counting the motor steps, detecting and eliminating motor blockage, storing and sending the patient's identification number and record information, such as the implantation date and the history of the last ten adjustments, and performing a self test on motor coils and other electronic components.

Upon receiving inductive power from the RF Board, the implant electronic system may enter the “Init”state4100, in which the microprocessors, the A/D converters, the input/output devices, interrupt devices, comparator, and watchdog devices may be initialized. Once the initialization is completed, the implant electronic system may enter the “Power On Self Test”state4102, in which the motor coils may be tested. If the self test is successful, the implant electronic system may enter the “Send ID”state4108. Otherwise, the implant electronic system may enter the “Error Detected” state4104, in which the RF transponder may notify thecontrol device110 with the appropriate message.

The “Send ID”state4102 may be the default state, such that it may loop itself and continuously send ID messages back to thecontrol device110 until additional command is sent form the control device.

Referring toFIGS. 42A and 42B, the data structure of the ID messages may include three ID bytes, two status bytes, three motor position bytes, and one CRC code check byte.

Referring again toFIG. 41, the implant electronic system may transit out of the “Send ID”state4102 once it receives a command from the control device. For example, the implantation date will be recorded in the EEPROM in the “Record Date”state4112 if a “record date” command is received and the implantation flag is False. For another example, the last 10 implant's positions will be sent back to the control device during the “Send History”state4116 if a “send history” command is received.

Moreover, the implant electronic system may enter the “Adjust Band”state4110 if an “Open” or “Close” command is received. During the “Adjust Band” state, the motor sequence may be activated, such that the motor may be directed to rotate clockwise or counter-clockwise.

A complete list of commands and the associating transmission protocol can be found onFIGS. 43B and 44B. Particularly,FIG. 43B illustrates the data structure of commands that do not require additional parameters being sent to the implant, whereasFIG. 44B illustrates the data structure of commands that require additional parameter.

Among the no-parameter commands, the “ImplantRequestStopPower” command may instruct the implant to stop powering the motor; the “ImplantRequestSelfTest” command may request the implant to perform a self test procedure; the “ImplantGetCurrentDate” command may request the implant to get the current date; the “ImplantGetSerialNumber” may instruct the implant to get the serial number; the “ImplantGetFirmwareVersion” may instruct the implant to get the firmware version; the “ImplantGetStepCounter” command may instruct the implant to gets the current motor step counter; the “ImplantEepromRecovery” command may instruct the implant to recover all stored EEPROM memory; and the “ImplantGetExtendedStatusRegister” command may instruct the implant to get value of an extended status register.

Among the with-parameter commands, the “ImplantOpenNStep” command may ask the implant to turn the stepper motor clockwise by a number of steps in order to open the band; the “ImplantCloseNStep” command may ask the implant to turn the stepper motor counter-clockwise by N number of steps in order to close the band; the “ImplantWriteByteEeprom” command may instruct the implant to write a byte of data into the EEPROM; the “ImplantSetCurrentDate” command may instruct the implant to set and store the current date; the “ImplantReadHistory” command may instruct the implant to read the adjustment history; the “ImplantGetParameters” command may instruct the implant to get some specific parameters; and the “ImplantReadEepromRecovery” may instruct the implant to recover a specific record stored in EEPROM.

Referring again toFIG. 41, motor coil currents may be monitored during the motor sequence initialization and throughout the motor rotation phase for detecting and eliminating motor blockage. If a motor blockage is detected, the implant electronic system may enter the “Unblock Motor”state4106 to resolve the motor blockage issue. In one embodiment, the motor may be directed to reduce its rotation speed, so that it may generate more torque to overcome the motor blockage. In another embodiment, the motor may be directed to change the rotation direction if the motor speed reduction scheme fails to remove the motor blockage.

If these two schemes do not resolve the motor blockage issue, the implant electronic system may enter the “Error Detected” state4104, in which an error message will be sent to thecontrol device110.

Otherwise, the implant electronic system may return to the “Adjust Band”state4110 to continue adjusting the gastric band. When the adjustment is completed, the implant electronic system may enter the “Record Implant Position”state4118, in which the last adjustment and the received date will be recorded in the EEPROM.

The discussion now turns to the communication protocol between the control device and the implant electronic system.FIG. 49 shows a timing diagram of a computer interrupt sequence upon a detection of a control device command at the implant. Thecommand4904 may be sent by the control device, and it may be carried by an amplitude modulation signal at a carrier frequency of about 27 MHz. Once thecommand4904 is separated from the carrier, it may be fed to a comparator to generate the interruptsequence4902. Referring to thedigital sequence4906, the interrupts may be used for starting and/or stopping a timer. For example, a low state values (bit0) and a high state values (bit1) may be characterized as a short period and a long period, respectively.

Referring toFIG. 43A, the implant may acknowledge the reception of a command by responding with an ACK message if the command does not contain any parameter. Referring to theFIG. 44A, the control device may send a command with parameters. In one embodiment, the parameters and the Cyclic Redundant Check (CRC) code may be sent at about 2 ms intervals. If the CRC code verification is successful, the implant may then respond with an ACK message, which may confirm that the command is properly received. Otherwise, the implant may send a NACK message to prompt the control device to resend the command. As shown inFIGS. 45A and 45B, the data structures of the ACK message and the NACK message may be similar except for the last four bits.

Referring toFIG. 46A, several commands may request information from the implant. In response, the implant may embed the requested information in a response message. Upon receiving the response message and the embedded information, the control device may respond with an ACK message.

InFIG. 46B, a data structure of a response message is shown according to an embodiment of the present invention. Generally, the response message may include a start bit, two synchronization bits, eight “length” bits, several response message bits the size of which is defined by the value contains in the “length” bits, and eight CRC bits.

Referring toFIGS. 47A and 47B, several timeout conditions may be met when the implant takes more than 200 ms to send back either an ACK message or a response message. Generally, timeout conditions and/or a NACK message from the implant may trigger the resending of commands from the control device. According to an embodiment of the present invention, this resending mechanism may repeat up to about five times.

FIG. 50 shows a screen shot of the timing diagrams of the control device's command and the implant's response. The response time t_respmay be measured from the sending of the command5010 (from the control device110) to the sending of the response5020 (from the implant). The start pulse duration t_sdmay be the duration for transmitting the first response pulse, and the data bit duration t_dbmay be the duration for transmitting one message data bit. In one embodiment, the start pulse duration t_sdmay be set at 400 μs and the data bit duration t_dbmay be set at 200 μs. In order to instruct the microcontroller to stop its current task and get ready to receive the message, the start bit duration may be set to low.

The discussion now turns to the gastric band adjustment history storage function of the implant electronic system. InFIG. 48, a data structure of implant adjustment history record4800 (hereafter “history data record”) may be shown according to an embodiment of the present invention. Generally, thehistory data record4800 may reserve four bytes for storing gastric band position information, three bytes for storing date information, and one byte for storing CRC code.

Particularly, the gastric band position may be represented by about 71,000 motor steps, which may be stored in the four-byte data field. Because the EEPROM in the CAD has a size of about 512 bytes, information may normally be stored in duplicates of 256-byte size in a first record location and a second record location. Advantageously, the implant electronic device may be able to use the second set of records for data if the first set of records is corrupted.

The motor used in the implant may be a step motor. One step of the motor may correspond to one binary value stored in the counter. The stored value of “0” may represent a substantially (or fully) open band, while a stored value of “71,000” may represent a substantially (or fully) closed band. Moreover, more than one control devices may access and retrieve information from the implant, such that multiple care-takers and/or physicians may monitor and adjust the gastric band for the patient.

The discussion now turns to the operation of the motor. Referring toFIGS. 55A-55B a perspective top view and a perspective bottom view of amotor5500 according to an embodiment of the present invention. Generally, themotor5500 may be used for implementing the functional features of themotor assembly3718 as shown inFIG. 37B. Themotor5500 may include theupper bearings5504,lower bearings5508, a set of motor gears5505, afirst motor coil5506, asecond motor coil5507, amaneuver channel5510, and amotor switch PCB5530.

Themotor switch PCB5530 may have a layer of gold plate over the copper layer and large pads for cleaner thermo soldering, and the set of motor gears5505 may be covered by dry lubrication with a diamond like coating (DLC) to achieve better surface tension for avoiding water drop formation.

Themaneuver channel5510 may be used for receiving the threaded section of the flexible screw. When the set ofgears5505 are turned, the flexible screw may be maneuvered along themaneuver channel5510. In a band widening step, for example, the flexible screw may be maneuvered from theupper bearing5504 side of themaneuver channel5510 to thelower bearing5508 side of themaneuver channel5510. In a band tightening step, for example, the flexible screw may be maneuvered from thelower bearing5508 side of themaneuver channel5510 to theupper bearing5504 side of themaneuver channel5510.

Themotor5500, themotor wires5522, and the flexible screw may be protected by several devices. Before entering themotor5500, for example, themotor wires5522 may be protected by themotor cable5524. At or near thelower bearings5508, for example, themotor wires5522 may be protected by acable cone5542 of a motor travelingPCB protection cap5540.

Referring toFIGS. 55E-55F, a perspective bottom view and a perspective top view of a motor travelingPCB protection cap5540 are shown according to an embodiment of the present invention. The motor travelingPCB protection cap5540 may include the cable cone and aPCB brace5544. Thecable cone5542 may be used for protecting themotor wires5522. ThePCB brace5544 may be used for protecting thelower bearings5508 and holding themotor switch PCB5530. The motor travelingPCB protection cap5540 may be made of a PEEK material, and it may be mounted to thelower bearing5508 of themotor5500.

FIGS. 55C-55D show a perspective bottom view and a perspective top view ofmotor cap5520 according to an embodiment of the present invention. Themotor cap5520 may cover the motor travelingPCB protection cap5540 and thereby providing further protection for thelower bearing5508 of themotor5500. Themotor cap5520 may define amaneuver aperture5526, which may help guide the longitudinal movement of theflexible screw5560. Themotor cap5520 may include a set offlanges5527, which may be used for anchoring to the skeleton5800. Themotor5500 may be partially secured by themotor cap5520 and the motor travelingPCB protection cap5540. After receiving and securing themotor5500, themotor cap5520 may anchor themotor5500 to the skeleton5800. Themotor cap5520 may have several rails to allow silicone to form overmolding thereon.

Themotor cable5524 and part of the flexible screw may be further protected by an overmold motor sleeve. Referring toFIGS. 55G-55H, a perspective side view and a perspective front view of amotor sleeve5550 are shown according to an embodiment of the present invention. Themotor sleeve5550 may be made of an LSR silicon material overmolded on a PEEK material. The LSR silicon overmolded PEEK may provide a sealing surface to protect fluid from entering themotor5500. Moreover, the motor sleeve5550 a plurality ofinternal bumps5552 to facilitate even gluing between the interior of themotor sleeve5550 and themotor cable5524.

FIG. 55I shows an exploded view of amotor coil5560 according to an embodiment of the present invention. Generally, themotor coil5560 may be used for implementing the first and/or

second motor coils

5506 and5507. Particularly, themotor coil5560 may include afirst connection board5564, asecond connection board5566, acore5562, aninner shield5570, acoil body5568, and anouter shield5572.

The first and

second connection boards

5564 and5566 may provide a connection interface between the motor wires and thecoil body5568. Moreover, the first and

second connection boards

5564 and5568 may help secure thecoil body5568 around the center of thecore5562. The first and

second connection boards

5564 and5568 may engage thecore5562 and sandwich thecoil body5568 between both ends of thecore5562. Thecoil body5568 may have several coils that are made of silver wire. When current passes through the coils, thecoil body5568 may induce a magnetic flux along thecore5562. The inner and

outer shield

5570 and5572 may shield thecoil body5568 from electromagnetic interference, such that the magnetic flux generated by one motor coil (e.g., themotor coil5506 or5507) will not interfere with the magnetic flux generated by another motor coil (e.g., themotor coil5507 or5506).

FIGS. 55J-55K show various views of themotor cable5524 according to an embodiment of the present invention. Generally, themotor cable5524 may include acentral conductor5521, ninetwisted wires5522, and aPTFE tape5525. Thecentral conductor5521 may be crimped and attached to themotor5500 on one end, and it may be crimped and soldered to the implantelectronic system PCB3722 on the other end. Thecentral conductor5521 may be a ground wire or a skeleton wire depending on the particular circuit configuration being used.

Specifically, thecentral conductor5521 may include ninety-one MP35NLT alloy wires each with diameter of 0.04 mm. The ninetwisted wires5522 may be connected to the first and second motor coils or the end of a travel switch. Each of the ninetwisted wires5522 may include seven AISI316L silver platedstainless steel wires5523, each of which may have a diameter of 0.12 mm.

FIG. 56 shows a side view of aflexible screw assembly5600 according to an embodiment of the present invention. Generally, theflexible screw assembly5600 may be used for implementing the functional features of theflexible screw assembly3720. Theflexible screw assembly5600 may have ahook end5602, acentral wire5604, an intercalary wire (threaded section)5605, and acrimped end5608. Thecentral wire5604 may be surrounded by the stabilizing tube as discussed inFIG. 37B, and it may be attached to the end of theintercalary wire5605 opposite to acrimped end5608. Moreover, thecentral wire5604 may be used for controlling the size of the gastric band when theintercalary wire5605 is being moved back and forth themaneuver channel5510 of the motor5500 (seeFIGS. 55A and 55B).

Theflexible screw assembly5600 may have anoverall length5612 of about 136.20 mm and with a tolerant range of about 0.1 mm. Theintercalary wire5605 may have anoverall length5614 of about 52 mm and with a tolerant range of about 0.1 mm. Thehook member5602 may have awidth5601 and alength5618. Thewidth5601 may be about 2.5 mm and with a tolerant range of about 0.1 mm, whereas thelength5618 may be about 8 mm and with a tolerant range of about 0.1 mm.

FIGS. 57A-57H provide various views of themotor5500 engaging theflexible screw5600 to illustrate the structural and functional relationships between themotor5500 and theflexible screw assembly5600. Initially, each of the first and

second motor coils

5506 and5507 may receive a motor current from the implantelectronic device PCB3722 and via themotor wires5522. The first andsecond motor coils5506 may each generate a magnetic flux in response to the received motor current. The generated magnetic flux may be collected by thestator5547, which may convert the magnetic flux to mechanical force for driving a set ofrotors5541.

The set ofrotors5541 may be engaged to and for driving the set ofgears5505. The set ofgears5505 may include a set ofauxiliary gears5543 and aprimary gear5545. The set ofauxiliary gears5543 may be engaged between therotor5541 and theprimary gear5545, such that the set ofauxiliary gears5543 may redirect the mechanical force from therotor5543 to theprimary gear5545.

Theprimary gear5545 may be positioned within themaneuver channel5510. Theupper bearings5504 and thelower bearings5508 may help position, stabilize, and secure theprimary gear5545 within themaneuver channel5510. Theprimary gear5545 may have an internal threaded section for engaging the external thread of theintercalary wire5606 of theflexible screw5600. When theprimary gear5545 is set to rotate, it may move theintercalary wire5606 along themaneuver channel5510. As such, upon receiving the mechanical force, theprimary gear5545 may actual a relative longitudinal movement between themotor5500 and theflexible screw5600.

Because of the relative longitudinal movement actuated by theprimary gear5545, themotor5500 may slide along theintercalary wire5606. When the gastric band is formed, thehook end5602 of theflexible screw5600 may be positioned in the proximity of themotor5500. As such, the size of the gastric band, which can be defined in diameter and/or circumference, may be adjusted by varying a relative distance between thehook end5602 and an engagement position on theintercalary wire5606. More specifically, the engagement position is a position at which themotor5500 may engage theintercalary wire5606. The size of the gastric band may be increased by sliding themotor5500 toward thecrimped end5608 of theflexible screw5600. Similarly, the size of the gastric band may be reduced by sliding themotor5500 toward thehook end5602 of theflexible screw5600.

The discussion now turns to the motor and the motor blockage detection mechanism. Referring toFIG. 51, a schematic view of a motor coilcurrent measurement system5100 is shown according to an embodiment of the present invention. The connection between the motor and the implant electronic device may be established via ten conductor cable wires. The

cable wires

5122 and5124 may be connected to the screw end of a travel switch. In one embodiment, thecable wire5122 may be one of themotor wires5522, and thecable wire5124 may be thecenter conductor5521 as shown inFIG. 55K.

Generally, the eight cable wires connecting to the motor coils may be duplicated and connected in parallel. In one embodiment, for example, thecable wire5102 may duplicate thecable wire5104, thecable wire5106 may duplicate thecable wire5108, thecable wire5112 may duplicate thecable wire5114, and thecable wire5116 may duplicate thecable wire5118. Each of the

cable wires

5102,5104,5106,5108,5112,5114,5116, and5118 may be implemented by one of the ninemotor wires5522 as shown inFIG. 55K.

The

cable wires

5102 and5104 may be connected to a first end of themotor coil2, while the

cable wires

5106 and5108 may be connected to a second end of themotor coil2. Similarly, the

cable wires

5112 and5114 may be connected to a first end of themotor coil1, while the

cable wires

5116 and5118 may be connected to a second end of themotor coil1.

As previously discussed, the control device may request the patient's identification number and history data from the implant electronic system before the gastric band adjustment process. In response, the implant electronic system may retrieve and send back the requested information. After receiving the requested information, the control device may be ready for adjustment. At this point, the user may elect to tighten or loosen the gastric band.

When the electronic device receives band adjustment commands from the control device, it may initiate a motor-on sequence which may include a motor positioning phase, a motor startup phase, and a motor drive phase. During the motor position phase, the motor is moved to a known position prior to the actual rotation start. Table 3 may illustrate the motor positioning phase:

TABLE 3

Sequences during motor positioning.

	Direction	Duration [ms]	Coil 1	Coil 2

Band Closing	5	NEG	POS
	60	NEG	NEG
Band Opening
5	POS	POS
	60	POS	NEG

A positive pulse POS and a negative pulse NEG may be used for driving the motor coils. During a band closing sequence, for example, the first motor coil may receive a negative pulse for 5 ms and then another negative pulse for 60 ms, whereas the second motor coil may receive a positive pulse for 5 ms and a negative pulse for 60 ms. Table 4 may provide four pulse pair steps for rotating the motor:

TABLE 4

Sequences for motor rotation.

1	Coil 2	Coil 1	Coil 2

	PPL0	POS	NEG	NEG	NEG
	PPL1	POS	POS	NEG	POS
	PPL2	NEG	POS	POS	POS
	PPL3	NEG	NEG	POS	NEG

The pulse pair (PP) combination parameters may be stored in the implant electronic device's EEPROM. Generally, two pairs of pulses may drive a full turn of the motor, thereby completing a single motor step. Accordingly, two motor steps may be completed after executing pulse pairs PPL0 to PPL3. The completion of each motor step may be reported back to the control device for monitoring purposes. During the motor startup phase, the duration of the pulses may be gradually decreased from about 5.12 ms down to about 2.6 ms with a delta of about 0.15 ms after each pulse.

During the motor drive phase, a motor blockage may be detected. The motor drive phase may be used for refining a minimal pulse duration, which may range from about 2.6 ms to about 1.2 ms. The minimal pulse duration may allow the motor coils to turn smoothly without any motor blockage.

Referring again toFIG. 51, the minimal pulse duration may be refined by detecting the motor coil currents across theresistors5132 and/or5134. The motor coil currents may be amplified by an analog amplifier and then digitized by an analog-to-digital converter (ADC). In one embodiment, the analog amplifier may be configured to have an amplifying power of 32, and the ADC may be configured to generate a 10-bit digital number for representing the value of the motor coil current.

Generally, the resistance of the

resistors

5132 and5134 may be much smaller than the resistance of the motor coils5142 and5144. In one embodiment, for example, the resistance of the

motor coil

5142 or5144 may be 167 times of the resistance of the

resistor

5132 or5134. In another embodiment, for example, the resistance of the

resistors

5132 and5134 may each be about 3.6Ω, whereas the resistance of the motor coils5142 and5144 may each be about 600Ω. As such, the voltage drop across the

resistors

5132 and5134 may be minimal when compared to the voltage drop across the

motor coil resistors

5142 and5144. Therefore, the resistance of the

resistors

5132 and5134 may have little effect on the overall current flowing of the first and second motor coils.

Sources of motor blockage may include increased force required to close the band as its materials get more compressed. As the radius of the band reduces, it would also become more difficult to pull on theflexible screw5600 regardless of the presence of other materials. Biological tissue also gets more compressed as radius decreases, leading to more required force from the motor. The motor may be rated at a pulling force of 20 N but with typical pulling force of 27 N, such that it would get stalled as the required force would be higher than the typical pulling force.

The trend of motor coil current may indicate motor blockage or the lack thereof. As shown inFIG. 52, for example, a firstcurrent profile5206 may represent a motor coil current of an unblocked motor, and a secondcurrent profile5208 may represent a motor coil current of a blocked motor. In general, the resistance of a blocked motor may be higher than an unblocked motor. To maintain a relatively constant voltage across the motor, the motor coil current of a blocked motor (e.g., the second current profile5208) may increase rapidly during aninitial period5201 of a motor step but slowly during amiddle period5202 of the motor step.

On the other hand, the resistance of an unblocked motor is typically lower than that of a blocked motor. As such, the motor coil current of an unblocked motor (e.g., the first current profile5206) may increase slowly during theinitial period5201 but rapidly during themiddle period5202. Both motor coil currents (e.g., the first and secondcurrent profiles5206 and5208) may reach a maximum motor coil current5209 at anending period5204 of the motor step. However, during themiddle period5202, the integral sum of the blocked motor coil current (e.g., the second current profile5208) may be much greater than the integral sum of the unblocked motor coil current (e.g., the first current profile5206). This phenomenon may be attributed by the early ramping of the blocked motor coil current and the late ramping of the unblocked motor coiled current.

Based on several measurements, the integral sum of the blocked motor current during themiddle period5202 is typically greater than the maximum motor coil current5209. To the contrary, the integral sum of the unblocked motor current during themiddle period5202 is typically less than the maximum motor coil current5209. As such, the integral sum of a particular motor coil current during themiddle period5202 may be compared to the maximum motor coil current5209 in determining whether the motor is blocked.

According to an embodiment of the present invention and as shown inFIG. 54, the implant electronic device (e.g., a processing device) may execute a software algorithm for detecting motor blockage. The software algorithm may take advantage of the aforementioned principle, and it may be stored in a tangible computer readable medium. In one embodiment, for example, the tangible computer readable medium may include a flash memory in the implant electronic device. In another embodiment, for example, the tangible computer readable medium may include, but not limited to, random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk, removable disk, CD-ROM, DVD, Blu-ray disk, wireless channels, and various other media capable of storing, containing or carrying instruction(s) and/or data. In yet another embodiment, the motor coil current may be measured by the implant electronic device, while the motor blockage detection software algorithm may be stored in and executed by the control unit.

Instep5302, an integral sum value (idt) may be calculated by measuring the integral sum of motor coil current (Integral_idt) and normalizing the measurement. In one embodiment, the measurement may be performed during the PPL2 pulse pair, and the normalization may be performed by multiplying the measured integral sum of motor coil current (Integral_idt) by a predetermined parameter (constant_idt).

Instep5304, the maximum current (crt) may be calculated by measuring the maximum motor coil current (Current_Max) and normalizing the measurement. In one embodiment, the measurement may be performed during the PPL3 pulse pair, and the normalization may be performed by multiplying the measured maximum motor coil current (Current_Max) by a predetermined parameter (constant_Max).

Instep5308, a determination can be made regarding whether the integral sum value (idt) is greater than the maximum current (crt). If a positive determination is made, the algorithm may proceed to step5308, in which the value of a block register (iBlock) may be augmented. The block register value augmentation may be representative of the possibility that the motor is blocked. Hence, the higher the value of block register is, the more likely that the motor blockage has occurred.

On the other hand, if a negative determination is made instep5308, the algorithm may proceed to step5312, in which the value of the block register (iBlock) may be compared with a predefined value. If the value of the block register is less than the predefined value, areduction step5316 may be executed for reducing the value of the block register. In one embodiment, the value of the block register may be a negative number. If the value of the block register is greater than the predefined value, anincrement step5314 may be executed for augmenting the value of the block register.

Instep5320, a determination is made regarding whether a motor blockage has occurred. The value of the block register may be compared with a predefined threshold. The predefined threshold may represent a threshold probability that a motor blockage has occurred. If the value of the block register does not reach the predefined threshold, the algorithm may assume no motor blockage has happened yet, and it may return to step5302 for the next motor sequence. However, if the value of the block register exceeds the predefined threshold, the algorithm may determine that the motor is blocked, and it may enter a different sequence.

Once a motor blockage is detected, the implant electronic device may direct the motor to decrease its speed and to enhance the motor torque. In one embodiment, for example, the implant electronic device may decrease the pulse duration to about 1.2 ms to produce more motor torque. If the motor load decreases, thereby requiring less motor torque, the implant electronic device may direct the motor to increase its speed again.

The discussion now turns to several gastric band components. Referring toFIGS. 58A-58C, various views of a bendable skeleton5800 may be shown according to an embodiment of the present invention. Generally, the bendable skeleton5800 may be used for implementing the functional features of theskeleton3814. The bendable skeleton may be made of a PEEK material, which may be corrosion resistive and durable against stress.

The bendable skeleton5800 may have anopen compartment5802 for receiving and securing the motor, aladder body5804 for supporting the dorsal ring surface of the gastric band, and adistal end member5806 for providing an anchor point for the hook end (element)5602 of theflexible screw5600 to the first end of the dorsal element. Theladder body5804 may also embrace the stabilizingtube5820. In return, the stabilizingtube5802 may guide the center wire of the flexible screw assembly to travel from theopen compartment5802 to thedistal end member5806 of the bendable skeleton5800.

Theopen compartment5802 may have adiameter5808, avertical distance5810 separating theopen compartment5802 and thedistal end member5806, and anoverall length5812. In one embodiment, the diameter5805 may be about 13.6 mm, thevertical distance5810 may be about 67.6 mm, and theoverall length5812 may be about 111.23 mm.

FIGS. 59A-59B show a perspective view and a cross-sectional view of the stabilizingtube5820 according to an embodiment of the present invention. Generally, the stabilizingtube5820 may be made of an ePTFE material. The stabilizingtube5820 may have anoverall length5912, afirst height5914, asecond height5916, aradius5922, athickness5920, and achannel radius5918. In one embodiment, theoverall length5912 may be about 130 mm, thefirst height5914 may be about 2.55 mm, thesecond height5916 may be about 4.4 mm, theradius5922 may be about 5 mm, thethickness5920 may be about 3.5 mm, and thechannel diameter5918 may be about 3 mm.

FIGS. 60A-60D show various views of adorsal element6000 according to an embodiment of the present invention. Generally, thedorsal element6000 may be used for implementing the functional features of thedorsal element3704 as shown inFIG. 37B. Thedorsal element6000 may include anopen compartment6001, anopening6002, and a semi-tubular ring (body)6022 connecting theopen compartment6001 and theopening6002. The side wall of theopen compartment6001 may have a locking protrusion and a ring-lockedindicator6030 formed on the locking protrusion. During the band formation, theopen compartment6001 may be inserted into theopening6002, which may have a clip ring with alocking flange6006. The locking flange may have a port for securing the locking protrusion. Once the locking protrusion is secured by the flange port, the ring-lock indicator6030 may become visible.

FIGS. 61A-61C show various views of ananti-slip cushion6100 according to an embodiment of the present invention. Thecushion6100 may have awidth6102, athickness6104, afirst length6106, and asecond length6110. In one embodiment, thewidth6102 may be about 17.92 mm, thethickness6104 may be about 4.42 mm, thefirst length6106 may be about 17.3 mm, and thesecond length6110 may be slightly shorter than thefirst length6106.

The front surface of thecushion6100 may be symmetrical along a vertical axis, and it may have a convex shield-like surface with an array ofcurvy groove lines6108 to provide more friction. Advantageously, thecurvy groove lines6108 may help the gastric band to remain in contact with the patient stomach and reduce the likelihood of band slippage. Moreover, the shield-like convex surface of thecushion6100 may efficiently stimulate the valgus nerve of the patient.

FIGS. 62A-62C show various views of amembrane shell6200 according to an embodiment of the present invention. In general, themembrane shell6200 may include a tubular structure made ofseveral segments6208. The tubular structure6202 may have a circular contour, and it may be used for encapsulating thedorsal element6000, the skeleton5800, and part of theflexible screw5600. Thesegments6208 may be used for receiving thecushions6100. Themembrane shell6200 may be made of several NuSil LSR silicones, depending on the level of hardness it is designed to achieve. In one embodiment, for example, themembrane shell6200 may be made of MED-4870, which is a silicone with a hardness of about 70 Shore A.

FIGS. 63A-63C show various views of a cushionedmembrane shell6300 according to an embodiment of the present invention. The cushionedmembrane shell6300 may includeseveral cushions6308, which may be made of MED-4801. When compared to MED-4870, MED-4801 may have a hardness of about 1 Shore A. Accordingly, the cushionedmembrane shell6300 may have a soft inner circumferential surface and a hard outer circumferential surface.

In an alternative embodiment, thecushions6308 may be made of a silicone elastomer external shell filled with saline solution or made of a silicone elastomer external shell filled with silicone gel. Specifically, the silicone elastomer for the cushions may have a hardness ranges from about 1 Shore A to about 10 Shore A, whereas the silicone elastomer for the membrane shell may have a hardness ranges from about 20 Shore A to about 45 Shore A.

Unless otherwise indicated, all numerical parameters used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

The terms “a,” “an,” “the,” and similar referents used in the context of describing the present invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the present invention and does not pose a limitation on the scope of the present invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the present invention.

Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

Certain embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Furthermore, certain references have been made to patents and printed publications throughout this specification. Each of the above-cited references and printed publications are individually incorporated herein by reference in their entirety.

Specific embodiments disclosed herein may be further limited in the claims using consisting of or consisting essentially of language. When used in the claims, whether as filed or added per amendment, the transition term “consisting of” excludes any element, step, or ingredient not specified in the claims. The transition term “consisting essentially of” limits the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic(s). Embodiments of the invention so claimed are inherently or expressly described and enabled herein.

In closing, it is to be understood that the embodiments of the present invention disclosed herein are illustrative of the principles of the present invention. Other modifications that may be employed are within the scope of the present invention. Thus, by way of example, but not of limitation, alternative configurations of the present invention may be utilized in accordance with the teachings herein. Accordingly, the present invention is not limited to that precisely as shown and described.