CN114765466A - Managing contactless communication and contactless charging and corresponding contactless device - Google Patents

Abstract

Embodiments of the present disclosure relate to managing contactless communication and contactless charging and corresponding contactless devices. A contactless device comprising an impedance matching and filtering circuit connected to an antenna and operable on the one hand to contactless communicate with a second device via the antenna and on the other hand to contactless charge a rechargeable power source of a third device via the antenna. A control method includes modifying an impedance matching and filtering circuit of a contactless device according to whether the contactless device performs contactless communication or contactless charging.

Description

Managing contactless communication and contactless charging and corresponding contactless device

Priority requirement

The present application claims priority from french patent application No.2100383 filed on 2021, month 1 and day 15, which is incorporated herein by reference in its entirety to the maximum extent allowed by law.

Technical Field

Implementations and embodiments relate to wireless or contactless communication using electronic components connected to an antenna, in particular components configured to exchange information with an external device via the antenna according to a contactless communication protocol. Implementations and embodiments relate to contactless charging of an object (such as, but not limited to, a connected watch) by a contactless device incorporating such components, for example incorporated in a mobile phone of the "smartphone" type.

Background

Such components are more simply referred to as "contactless components" and may be, for example, so-called Near Field Communication (NFC) technology components, i.e. components compatible with NFC technology.

NFC technology components use near field, i.e. short range, high frequency wireless communication technology, which makes it possible to exchange data between two contactless devices over a short range (e.g. 10 cm).

NFC technology is standardized in the documents ISO/IEC18092 and ISO/IEC 21481, but incorporates a number of pre-existing standards, including the type a and type B protocols of the standard ISO/IEC 14443.

The NFC component may be, for example, an NFC microcontroller.

An NFC microcontroller can generally be used to talk to another contactless device, for example by using a contactless communication protocol, for example the type a protocol of the standard ISO/IEC 14443.

In addition to the contactless communication function provided by the NFC technology, contactless charging of a contactless device by another contactless device using the NFC technology begins to occur. In this regard, standards of the NFC forum association entitled "wireless charging" are currently provided.

Therefore, in the NFC technology, an electromagnetic field of a frequency of 13.56MHz is used to perform conventional communication between two contactless devices, and to perform contactless charging between a contactless device incorporated in, for example, a cellular mobile phone of a smartphone type and a portable contactless object such as a connected watch, a headset, or the like.

Therefore, there is a need to propose a technical solution for a contactless device which provides a conventional contactless communication function and a contactless charging function and which is particularly compact so as to be able to be easily integrated into a small device, for example a cellular mobile phone of the smartphone type.

Disclosure of Invention

According to one implementation and embodiment, it is proposed to perform both functions (i.e. contactless communication function and contactless charging function) using a single impedance matching and filtering circuit and a single antenna.

According to one aspect, a method for managing operation of a contactless device is presented.

The apparatus includes an impedance matching and filtering circuit connected to the antenna.

In one aspect, the device is capable of contactless communication with a second device via the antenna.

In another aspect, the device is capable of contactless charging, via the antenna, a rechargeable power source coupled to a third device during at least one charging session.

The contactless communication with the second device via said antenna and the contactless charging of the rechargeable power supply device advantageously use an electromagnetic field having the same frequency, in particular the NFC frequency, for example 13.56 MHz.

A rechargeable power source coupled to a third device is understood to be able to be incorporated into or even linked to the third device, but located in an object incorporated into the third device.

It should be noted that the third device may be a different device than the second device, or even the second device itself, as will be explained in more detail below.

In other words, in the last case, the device can communicate, for example, contactlessly with a second device, for example to exchange information, and then charge the second device if necessary.

The method according to this aspect includes modifying, by the device, the impedance matching and filtering circuit according to whether the device performs the contactless communication function or whether the contactless charging function is performed during the at least one charging session.

Thus, according to this aspect, the same antenna and impedance matching and filtering circuit for contactless communication and contactless charging is used, the characteristics of which can be modified, such as the capacitance value and the resistance value.

It should be noted that the modification of the impedance matching and filtering circuit is advantageously performed automatically by the device, for example upon reception of a charging request.

For contactless communication, the characteristics of the matching and filtering circuit of a device are determined, for example, in the laboratory independently of the characteristics of any other second device with which it must have a contactless dialogue, since this adjustment of the impedance matching and filtering circuit is made without any metallic coupling close to the device.

However, for contactless charging of a third contactless device, the characteristics of the matching and filtering circuit of the device are determined, for example in a laboratory, in particular for this third device placed in the vicinity of the charger device, in order to take into account in particular the metallic structure specific to the third device and to optimize the power transfer as much as possible.

According to one implementation, the impedance matching and filtering circuit is a configurable circuit, and said modifying of the circuit comprises placing said configurable circuit by the device in a first configuration compatible with said contactless communication or placing said circuit by the device in a second configuration compatible with said contactless charging.

According to one embodiment, the device comprises a processing unit having two output terminals connected to said antenna through said filtering and impedance matching circuit, the first configuration being valid independently of the second device and the second configuration being dedicated to the third device, and the filtering and impedance matching circuit being arranged such that the impedance seen at the input of the output terminals of the processing unit is constant or substantially constant within a tolerance of, for example, less than 10%, regardless of the configuration of the filtering and impedance matching circuit.

According to one embodiment, the apparatus comprises a control circuit, and the placement of the filtering and impedance matching circuit in its first configuration or its second configuration comprises: transmitting, by a control circuit, a control signal to the filtering and impedance matching circuit, the control signal having a first value associated with a first configuration of a third device or a second value associated with a second particular configuration; wherein the filtering and impedance matching circuit switches between its first configuration and its second configuration in dependence on the value of the control signal.

According to one implementation, the device is capable of charging the rechargeable power source according to a contactless charging protocol comprising the at least one charging session and at least one contactless communication phase with a third device. The contactless communication phase enables, inter alia, the exchange of information relating to the required charging time and/or the required charging power.

Further, during the contactless charging protocol, the device may place the impedance matching and filtering circuit in its second configuration during each charging session and in its first configuration during each contactless communication phase.

On the other hand, the contactless communication phase for exchanging charging information is usually a very short phase.

Thus, alternatively, and for simplicity, the device may place the impedance matching and filtering circuit in its second configuration during each charging session and during each contactless communication phase.

In other words, in this case, the impedance matching and filtering circuit is not modified between each charging session and each communication phase.

According to one implementation, a device changes to a contactless charging protocol in response to a first control signal issued from a third device, and begins a charging session in response to a second control signal issued from the third device.

The device may comprise a processing unit, such as a microprocessor or microcontroller, having two outputs connected to the antenna through the impedance matching and filtering circuit.

The circuit may include: a first inductive capacitance module connected between the two output terminals and a power supply reference (e.g., ground); a second capacitance module connected between each output terminal and a power supply reference point; and a resistance module connected between each output terminal and a power supply reference point.

According to one implementation, the modification of the impedance matching and filtering circuit includes: when the device changes from contactless communication to contactless charging during the at least one charging session, increasing the capacitance value of the first module, decreasing the capacitance value of each second module, and deactivating the resistive modules.

The modification of the impedance matching and filtering circuit may be performed in response to a control signal transmitted by a control circuit, for example incorporated in the processing unit, in particular in response to the first control signal or the second control signal.

The third device may belong to a set of multiple possible third devices respectively associated with different configurations of impedance matching and filtering circuits of the device during a charging session.

The method may then advantageously comprise detecting, by the device, the group of third devices requiring contactless charging, and selecting, by the device, a corresponding configuration of the impedance matching and filtering circuit.

According to another aspect, a contactless device is presented that includes an impedance matching and filtering circuit connected to an antenna.

The device is on the one hand capable of contactless communication with a second device via said antenna and on the other hand capable of contactless charging of a rechargeable power source of a third device via said antenna during at least one charging session.

The device includes a control circuit configured to modify an impedance matching and filtering circuit depending on whether the device performs the contactless communication or the contactless charging during the at least one charging session.

According to one embodiment, the impedance matching and filtering circuit is a configurable circuit and the control circuit is configured to place the configurable circuit in a first configuration compatible with said contactless communication or in a second configuration compatible with said contactless charging.

According to one embodiment, the device is capable of charging the rechargeable power source according to a contactless charging protocol comprising the at least one charging session and at least one contactless communication phase with a third device, and the control circuit is configured to place the circuit in its second configuration during each charging session and to place the circuit in its first configuration during each contactless communication phase.

According to another possible embodiment, the device is capable of charging the rechargeable power source according to a contactless charging protocol comprising said at least one charging session and at least one contactless communication phase with the third device, and the control circuit is configured to place said circuit in its second configuration during each charging session and during each contactless communication phase.

According to one embodiment, the device is configured to change to a contactless charging protocol in response to a first control signal issued from a third device, and is configured to start a charging session in response to a second control signal issued from the third device.

According to one embodiment, the device comprises a processing unit having two output terminals connected to said antenna through said circuit.

The impedance matching and filtering circuit includes: a first inductive capacitance module connected between the two output terminals and a power supply reference point; a second capacitance module connected between each output terminal and a power supply reference point; and a resistance module connected between each output terminal and a power supply reference point.

The control circuit is configured to increase a capacitance value of the first module, decrease a capacitance value of each second module, and disable the resistive modules when the device changes from contactless communication to contactless charging during the at least one charging session.

According to one embodiment, the processing unit comprises a control circuit.

According to one embodiment, the control circuit is configured to modify the circuit in response to the first control signal or the second control signal.

According to one embodiment, the apparatus comprises: a memory circuit storing a set of different configurations of impedance matching and filtering circuits that may be used during a charging session and that are respectively associated with a plurality of possible third devices; a detection circuit configured to detect a third device of the group requiring contactless charging, and a selection circuit configured to perform a selection of a respective configuration of the impedance matching and filtering circuit.

According to another aspect, a mobile phone, for example of the "smartphone" type, is proposed, which incorporates a device as defined above.

Drawings

Other advantages and features will become apparent by examining the detailed description of non-limiting implementations and embodiments and the accompanying drawings, in which:

fig. 1 shows a system comprising two contactless devices for wireless communication;

fig. 2 shows a system comprising two contactless devices for wireless charging;

FIG. 3 is a block diagram of a contactless device;

FIG. 4 is a flow chart of a method of operation;

FIG. 5 is a circuit diagram of an impedance matching and filtering circuit;

FIGS. 6 and 7 illustrate varying configurations of the impedance matching and filtering circuit of FIG. 5;

FIG. 8 is a flow chart of a method of operation;

FIG. 9 illustrates an example of a contactless charging protocol; and

fig. 10 schematically shows the configuration selection.

Detailed Description

In fig. 1, reference numeral DV denotes a contactless device incorporated, for example, within a communication device APP such as a cellular mobile phone of the "smartphone" type.

Reference numeral DV2 denotes a second contactless device incorporated in, for example, an object (e.g., a smart card CP). The device DV is able to communicate contactlessly with the second device DV2 by using a near-field contactless communication protocol, for example the class a protocol of the standard ISO/IEC144443, without this being limitative, and operating at a near-field contactless communication frequency, for example a frequency of only 13.56 MHz.

The second device DV2 may also be incorporated into another cellular mobile phone to enable, for example, peer-to-peer communication.

In fig. 2, reference numeral DV3 denotes a third contactless device incorporated in the portable object OBJ, for example a connected watch.

Fig. 2 shows the application of contactless charging of a rechargeable power source, for example a battery BAT, of a device DV3 or of an object OBJ by means of the device DV.

Such contactless charging may be in accordance with the specifications indicated in the NFC forum document entitled wireless charging specification, version 1.0, 2020-03-31 [ VLC), to which those skilled in the art may refer for all useful purposes, and the charging signal is also at said near field contactless communication frequency.

Although fig. 2 shows an application of the noncontact charging function, the object OBJ may also be an object with which the device DV3 can perform noncontact communication with the device DV of the device APP according to a near field communication function similar to that shown in fig. 1.

Thus, for example, a device APP (e.g. a cellular mobile phone) may exchange information with an object (e.g. a connected watch) by using a contactless communication protocol. Subsequently, device APP can recharge object OBJ, for example a connected watch, when needed.

As shown in fig. 3, the contactless device DV comprises a processing unit UT, for example a microcontroller from the ST54J series of STMicroelectronics, which is connected to the two terminals BA of the antenna ANT by means of (i.e. through) an impedance matching and filtering circuit CFAD, the structure of which will be described in greater detail below.

The device DV also comprises a memory circuit MM for storage in certain applications, the content of which will be described in more detail below.

Specifically, as shown in fig. 4, when the device DV is switched from the noncontact communication function with the second device DV2 (step ST40) to the noncontact charging function of the third device DV3 (or DV2) (step ST42), a modification ST41 of the impedance matching and filter circuit CFAD is performed by the device DV itself.

An embodiment of the impedance matching and filtering circuit CFAD, which in this embodiment is a configurable circuit, is now described with more specific reference to fig. 5, 6 and 7.

As shown in fig. 5, circuit CFAD comprises an inductive capacitive module connected between the two outputs RFO1 and RFO2 of the processing unit.

More specifically, the inductive capacitive module comprises an inductive element LEMI and a capacitive element CEMI connected in series between the output terminal RFO1 and a reference node (e.g., ground GND), and an inductive element LEMI and a capacitive element CEMI connected in series between the second output terminal RFO2 and the reference node (ground GND).

The inductive capacitive modules constitute a filter for filtering electromagnetic interference (EMI), commonly designated as EMI filter by those skilled in the art. The filter thus makes it possible to reduce as far as possible the high-harmonic emissions from the transmission signal at said near-field contactless communication frequency, which is typically 13.56 MHz.

Two capacitors CS are also connected in series between the two inductive elements LEMI and the two terminals BA of the antenna ANT, respectively.

The circuit CFAD also comprises two capacitors CCDMP, respectively connected between the two terminals BA of the antenna ANT and the two terminals B1 of the processing unit, internally short-circuited to the reference node (ground GND).

The circuit CFAD further comprises two further auxiliary capacitors CCHG connected between the two capacitors CEMI and a reference node (ground) via two first NMOS transistors T1, respectively.

The two first NMOS transistors are controlled on their gates by a control signal DMP.

The elements LEMI, CEMI and CCHG constitute a first capacitive-inductive module.

The circuit CFAD further comprises two capacitive resistance modules MDRC connected between the two antenna terminals BA and the reference node (ground GND) by two second NMOS transistors T2, respectively, the gates of the two second NMOS transistors T2 being controlled by a control signal opposite to the signal DMP

And (5) controlling.

Each capacitive resistance module MDRC comprises a resistor RP and a capacitor CP connected in parallel.

Each capacitor CCDMP and each capacitor CP constitute a second capacitive module connected between the respective output terminal RFO1 or RFO2 and the reference node (ground GND).

Similarly, each resistor RP constitutes a resistance module connected between the respective output terminal RFO1 or RFO2 and the reference node (ground GND).

The processing unit also comprises a control circuit MC, which may be implemented, for example, by a logic circuit or by a software module, which transmits a control signal DMP on a terminal BC of the processing unit.

The inverter INV connected to the control terminal BC delivers opposite signals

Control circuit MC is thus configured by means of signals DMP and

the circuit CFAD is modified and in particular takes on the two configurations CFAD1 and CFAD2 shown in fig. 6 and 7, respectively.

The configuration CFAD1 shown in fig. 6 may be used during a contactless communication session between the device DV and another contactless device, while the configuration CFAD2 shown in fig. 7 may be used at least during each contactless charging session.

In fact, during the contactless communication session, impedance matching is performed without coupling, that is to say without a metallic part around the antenna ANT of the device DV, in order to obtain an optimized NFC communication performance at said near field contactless communication frequency in a wide operating volume, whereas during contactless charging, when the antenna ANT is coupled to the object to be charged, impedance matching is performed in order to have an optimized power transmission towards this object also at said near field contactless communication frequency.

The goal is to have a substantially constant impedance as input to terminals RFO1 and RFO2, e.g., a 7 ohm impedance, whether for contactless communication or for contactless charging.

Typically, when the device changes from contactless communication to contactless charging during said at least one charging session, the control circuit MC is configured to: increasing the capacitive value of the first module LEMI, CEMI, CCHG; reducing the capacitance value of each second module CCDMP, CP; and deactivating the resistance module RP.

Thus, more specifically, to change to the first configuration CFAD1 (fig. 6) available for contactless communication, the control circuit transmits a signal DMP having a logic value zero, which has the result of "deactivating" the capacitor CCHG and "activating" the resistor RP and the capacitor CP.

To change to the second configuration CFAD2 (fig. 7), the control circuit transmits the control signal DMP to the logic value 1, which has the result of "activating" the capacitor CCHG and "deactivating" the resistor RP and the capacitor CP.

Thus, as an example of a specific third device to be charged, capacitor CEMI may be selected to have a capacitance of 560 picofarads, capacitor CP 32 picofarads, resistor RP 1500 ohms, capacitor CCDMP 78 picofarads, and capacitor CS 200 picofarads.

Thus, it can be seen that the capacitance value of the first capacitive-inductive module CEMI, LEMI, CCHG changes from 560 picofarads to a value of 1230 picofarads in a contactless charging mode session during an NFC communication session.

However, the capacitance value of the second capacitance module CCDMP, CP changes from 110 picofarads in the NFC communication mode to 78 picofarads in the contactless charging mode.

Further, the resistance value of the resistance module changes from 1500 ohms in the NFC communication mode to "high impedance" in the contactless charging mode ("deactivating" the resistance module).

Of course, one skilled in the art would know how to adjust these values depending on the type of third device to be charged.

Therefore, as described above and as shown in fig. 8, when the device DV contactlessly communicates with the second device DV2 in accordance with the contactless communication protocol in step ST40, the device DV changes the circuit CFAD to the first configuration CFAD1 (step ST90), and when the device DV charges the device DV3 or DV2 during the charging session (step ST42), the device DV changes the circuit CFAD to its second configuration CFAD2 (step ST 91).

An example of a contactless charging protocol that conforms to the "wireless charging" specification of the NFC forum described above will now be described with more specific reference to fig. 9.

Those skilled in the art can refer to this document for all useful purposes.

Fig. 9 shows in a very simplified manner the negotiation mode for contactless charging.

In this negotiation mode, first, there is a first communication stage PC1 between the device DV (charger) and the contactless device to be charged (device DV 3).

The first communication phase PC1 is performed according to a contactless communication protocol.

The specification of the NFC forum platform entitled "simple specification version 1.0, 2017-03-14 [ SNEP ]" to which those skilled in the art can refer for all useful purposes defines the type of messages exchanged in the NFC communication protocol. Further, among these NDEF messages, a message WLC _ CAP exchanged between the device DV3 and the device DV appears. Thus, the device DV3 informs the device DV that the object it contains can be recharged.

When the device DV receives this signal WLC _ CAP, its state machine changes, and the device DV changes to contactless charging mode ("NFC charging").

The second communication phase PC2 then starts between the device DV and the device DV3, during which phase NDEF messages are exchanged again according to the contactless communication mode, and during which phase a message WLC _ CTL appears.

This message WLC _ CTL contains charging information, that is to say in particular the required charging time and charging power.

The reception of message WLC _ CAP serves as a first control signal and the reception of signal WLC _ CTL serves as a second control signal.

The second communication phase PC2 is followed by a charging session WPT, which is characterized by the second control signal WLC _ CTL.

Other charging cycles may follow, here two auxiliary charging cycles, comprising the communication phases PC3 and PC4 and the charging session WPT, respectively.

In a first alternative embodiment, the device DV may configure its impedance matching and filtering circuit CFAD during the stages PC1, PC2, PC3 and PC4 in a first configuration CFAD 1.

However, in response to the second control signal WLC _ CTL, the device DV will configure its impedance matching and filtering circuit CFAD to be in the second configuration CFAD2 during the charging session WPT.

Alternatively, the impedance matching and filtering circuit CFAD of the first control signal WLC _ CAPLC _ CAP is configured to the second configuration CFAD upon reception thereof₂(as shown in dashed lines at the bottom of fig. 9).

As described above, the CFAD is configured₁Device independent DV₂For contactless communication with the device DV, since the configuration is established without any coupling.

However, the second configuration CFAD₂Depending on the characteristics of the object to be recharged and in particular on the presence of metallic elements on the object.

Thus, as shown in FIG. 10, the memory circuit MM of the device DV may include respective and possible slave devicesN devices DV3 for DV charging₁，DV3_i，…，DV3_nAn associated set of n second configuration CFADs 2₁，CFAD2_i，…，CFAD2_n。

In practice, these various configurations may be realized, for example, by a plurality of auxiliary capacitors CCHG connected in parallel to a plurality of first transistors T1, respectively, whose respective gates of the plurality of first transistors T1 are to be controlled by a plurality of control signals DMP, respectively.

Similarly, the plurality of modules MDRC may also be respectively connected to the plurality of second transistors T2, wherein the corresponding gates will be respectively controlled by the plurality of control signals

And (5) controlling.

Alternatively, these multiple capacitor-transistor branches may be replaced by varistors.

When there are multiple possible third devices, the device DV may detect the presence of one of these devices to be charged, for example the device DV3_i(step ST100) to select (step ST101) the corresponding configuration CFAD2_i。

For example, due to the contents of an optional field of the LC _ CAP of the message WLC _ CAP.

The present invention is not limited to the embodiments and implementations just described.

Thus, a plurality of possible configurable circuits CFAD can be stored for the same third device to be charged, and the current consumed by the device DV for the emission of the electromagnetic field has been tested by the charger device DV for each possible circuit CFAD, in order to select the circuit CFAD corresponding to the efficiency target.

Claims (33)

1. A method for managing operation of a contactless device that includes an impedance matching and filtering circuit connected to an antenna and operable to support the contactless device in contactless communication with a second device via the antenna during a communication session and further operable to support the contactless device in contactless charging of a rechargeable power source of a third device via the antenna during a charging session, the method comprising:

modifying the impedance matching and filtering circuit to a first configuration that supports operation of the contactless device to perform the contactless communication with the second device during the communication session; and

modifying the impedance matching and filtering circuit to a second configuration that supports the contactless device operation to perform the contactless charging of the rechargeable power source of the third device during the charging session.

2. The method of claim 1, wherein the contactless communication with the second device via the antenna and the contactless charging of the rechargeable power source of the third device each use an electromagnetic field having a same frequency.

3. The method of claim 1, wherein the same frequency is a near field communication frequency of 13.56 MHz.

4. The method of claim 1, wherein the second device and the third device are the same device.

5. The method of claim 1, wherein the second device and the third device are different devices.

6. The method of claim 1, wherein the first configuration is compatible with contactless communication at a first frequency and the second configuration is compatible with contactless charging at a second frequency, and wherein the first frequency and the second frequency are the same frequency.

7. The method of claim 1, wherein the contactless device is operative to support contactless communication with the second device according to a near field communication protocol.

8. The method of claim 1, wherein the contactless device operates to support contactless charging according to a contactless charging protocol that includes the charging session and at least one contactless communication phase, and wherein the contactless device places the impedance matching and filtering circuit in the second configuration during the charging session and during the at least one contactless communication phase.

9. The method of claim 8, further comprising: changing to the contactless charging protocol in response to a first control signal received from the third device, and starting the charging session in response to a second control signal received from the third device.

10. The method of claim 9, wherein the contactless device comprises a processing unit having two output terminals connected to the antenna through the impedance matching and filtering circuit, wherein the impedance matching and filtering circuit comprises:

a first inductive capacitance module connected between the two output terminals and a power supply reference;

a second capacitance module connected between each output terminal and the power reference; and

a resistance module connected between each output terminal and the power reference;

wherein modifying the impedance matching and filtering circuit comprises: when changing from the first configuration to the second configuration to support the charging session,

increasing a capacitance value of the first inductive capacitance module;

reducing the capacitance value of the second capacitance module; and

deactivating the resistance module.

11. The method of claim 10, wherein the modifying of the impedance matching and filtering circuit is performed in response to a control signal communicated by a control circuit incorporated in the processing unit.

12. The method of claim 10, wherein modifying is performed in response to a control signal, the control signal being generated in response to one or both of the first and second control signals.

13. The method of claim 1, wherein the third device is one of a set of multiple possible third devices respectively associated with corresponding configurations of the impedance matching and filtering circuits during a charging session, the method comprising:

detecting the one device of the group requiring the contactless charging; and

selecting the corresponding configuration of the impedance matching and filtering circuit for the one device detected.

14. The method of claim 1, wherein the contactless device is incorporated into a mobile phone.

15. The method of claim 1, wherein the contactless device comprises a processing unit having two output terminals connected to the antenna through the filtering and impedance matching circuit, wherein the first configuration is valid independent of the second device and the second configuration is dedicated to the third device, and wherein the filtering and impedance matching circuit is arranged such that the impedance seen at the input of the output terminals of the processing unit is constant or substantially constant regardless of the configuration of the filtering and impedance matching circuit.

16. The method of claim 15, wherein the contactless device comprises a control circuit, and the modification of the filtering and impedance matching circuit in the first configuration or the second configuration comprises:

transmitting, by the control circuit, a control signal to the filtering and impedance matching circuit, the control signal having one of a first value associated with the first configuration or a second value associated with the second configuration, the second configuration being dedicated to the third device; and

wherein the filtering and impedance matching circuit switches between the first configuration and the second configuration according to the first value and the second value of the control signal, respectively.

17. A contactless device comprising:

an impedance matching and filtering circuit connected to the antenna;

a control circuit configured to modify the impedance matching and filtering circuit to have a first configuration that enables the contactless device to operate to perform contactless communication with a second device during a communication session, and to modify the impedance matching and filtering circuit to have a second configuration that enables the contactless device to operate to perform the contactless charging of a third device during a charging session.

18. The contactless device of claim 17, wherein the contactless communication with the second device via the antenna and the contactless charging of the rechargeable power source of the third device each use an electromagnetic field having a same frequency.

19. The contactless device of claim 1 wherein the same frequency is a near field communication frequency of 13.56 MHz.

20. The contactless device of claim 17, wherein the second device and the third device are the same device.

21. The contactless device of claim 17, wherein the second device and the third device are different devices.

22. The contactless device of claim 17, wherein the first configuration is compatible with contactless communication at a first frequency and the second configuration is compatible with contactless charging at a second frequency, and wherein the first frequency and the second frequency are the same frequency.

23. The contactless device of claim 17, wherein the contactless device is operative to support contactless communication with the second device according to a near field communication protocol.

24. The contactless device of claim 17, wherein the contactless device operates to support contactless charging according to a contactless charging protocol that includes the at least one charging session and at least one contactless communication phase, and wherein during each charging session and during the at least one contactless communication phase, the contactless device places the impedance matching and filtering circuit in the second configuration.

25. The contactless device of claim 24, wherein the contactless device is configured to change to the contactless charging protocol in response to a first control signal received from the third device, and to begin the charging session in response to a second control signal received from the third device.

26. The contactless device of claim 25, wherein the contactless device comprises a processing unit having two output terminals connected to the antenna through the impedance matching and filtering circuit, the impedance matching and filtering circuit comprising:

a first inductive capacitance module connected between the two output terminals and a power reference;

a second capacitance module connected between each output terminal and the power reference; and

a resistance module connected between each output terminal and the power reference, an

Wherein the control circuit is configured to increase the capacitance value of the first module, decrease the capacitance value of each second module and deactivate the resistance module when the device changes from contactless communication to contactless charging during the at least one charging session.

27. The contactless device of claim 26, wherein the control circuit is configured to transmit a control signal to the impedance matching and filtering circuit, the impedance matching and filtering circuit being configured to modify its configuration in response to the control signal.

28. The contactless device of claim 26, wherein the processing unit comprises the control circuit.

29. The contactless device of claim 26, wherein the control circuit is configured to modify in response to a control signal that is generated in response to one or both of the first and second control signals.

30. The contactless device of claim 17, further comprising:

a memory circuit storing a set of different configurations of the impedance matching and filters for use during the charging session and respectively associated with a plurality of possible third devices;

a detection circuit configured to detect one of the plurality of possible third devices that requires contactless charging; and

a selection circuit configured to select a configuration of the impedance matching and filtering circuit corresponding to the detected one device.

31. The contactless device of claim 17, comprising:

a processing unit having two output terminals connected to the antenna through the filtering and impedance matching circuit;

wherein the first configuration is valid regardless of the second device;

wherein the second configuration is dedicated to the third device;

wherein the filtering and impedance matching circuit is arranged such that the impedance seen at the input of the output terminal of the processing unit is constant or substantially constant regardless of the configuration of the filtering and impedance matching circuit.

32. The contactless device of claim 31, further comprising: a control circuit configured to transmit a control signal to the filtering and impedance matching circuit, the control signal having one of a first value associated with the first configuration of the third device or a second value associated with the second particular configuration;

wherein the filtering and impedance matching circuit is configured to switch between the first configuration and the second configuration according to the first value and the second value of the control signal, respectively.

33. A mobile phone comprising a contactless device according to claim 17.

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