Disclosure of Invention
In view of the foregoing, an object of the present invention is to provide a touch display control device and a touch display device, which can compensate for voltage fluctuation at a connection between the touch display device and a touch display panel, and reduce adjustment time, so as to avoid occurrence of cross lines or vertical lines on a display screen.
According to an aspect of the present invention, there is provided a touch display device including: the touch module is used for performing touch detection, and is provided with a plurality of touch detection channels so as to receive multi-path touch induction signals through the touch detection channels respectively for performing touch detection; the display control module is used for performing display control; a common voltage input module for providing a common voltage signal to a plurality of common voltage input nodes; the touch display control device comprises a plurality of touch detection channels, a plurality of common voltage input nodes, a selection module and a display control module, wherein the touch detection channels and the common voltage input nodes are selectively connected to a touch display panel, so that the display control module and the touch module perform display control and touch detection in a time-sharing mode, the touch display control device further comprises at least one compensation module connected between the selection module and the common voltage input nodes, each compensation module is connected with the corresponding common voltage input node to obtain corresponding node voltage, and a compensation control signal is generated according to a reference voltage and the node voltage and is used for gating a charging path or a discharging path connected with the common voltage input node; the compensation module includes: the first input end is connected with the public voltage input node to obtain corresponding node voltage; a second input for receiving a reference voltage; a control unit for generating the compensation control signal according to the node voltage and the reference voltage; the compensation module further includes a first transistor and a second transistor connected in series between a first supply voltage and a second supply voltage, first poles of the first transistor and the second transistor receiving the first supply voltage and the second supply voltage, respectively, second poles of the first transistor and the second transistor being connected to the common voltage input node, and control poles of the first transistor and the second transistor receiving the compensation control signal.
Preferably, the control unit comprises a hysteresis comparator; the hysteresis comparator comprises an output end, and the output end is respectively connected with the control electrode of the first transistor and the control electrode of the second transistor and is used for outputting the compensation control signal.
Preferably, the compensation control signal includes a first control signal and a second control signal; under the control of the first control signal, the first transistor is closed, the second transistor is opened, and the bleeder path is gated; under the control of the second control signal, the first transistor is turned on, the second transistor is turned off, and the charging path is gated, wherein the touch display control device comprises an upper limit threshold value and a lower limit threshold value, and the output end outputs the first control signal when the node voltage is higher than the upper limit threshold value; and when the node voltage is lower than the lower limit threshold value, the output end outputs the second control signal.
Preferably, the first supply voltage is higher than the second supply voltage; the first transistor comprises a P-type MOS transistor, and the second transistor comprises an N-type MOS transistor; the first electrode is a source electrode, the second electrode is a drain electrode, and the control electrode is a gate electrode.
Preferably, a plurality of connection points between the touch display control device and the touch display panel are used as the common voltage input nodes, and the touch display control device further comprises a plurality of compensation modules respectively connected with a plurality of common voltage input nodes, wherein each compensation module is used for generating the compensation control signals for the common voltage input nodes coupled to the corresponding compensation modules.
Preferably, the touch display control device is a touch and display driver integrated control device.
According to another aspect of the present invention, a touch display chip is provided, which includes the touch display control device as described above.
According to still another aspect of the present invention, there is provided a touch display device including: the touch display panel comprises a plurality of touch electrodes, wherein the touch electrodes are led out from the touch display panel through a plurality of touch lines; and the touch display control device as described above, wherein the touch module is connected to the plurality of touch lines, and each touch detection channel is connected to a corresponding touch line.
According to still another aspect of the present invention, there is provided an electronic device including the touch display control apparatus as described above.
The touch display control device and the touch display device provided by the embodiment of the invention comprise a buffer module for accelerating the pull-up and pull-down capability of the connection node of the touch display device and the touch display panel, wherein the buffer module comprises a hysteresis comparator and two different types of transistors, and when the voltage fluctuation of the connection node exceeds a preset interval in a display period, the compensation module pulls the voltage of the node back to the preset interval in a short time, so that the influence of the voltage fluctuation is reduced, the driving capability of the public voltage to the nodes is consistent, and the occurrence of transverse lines or vertical lines on a display picture is avoided.
The touch display control device and the touch display device provided by the embodiment of the invention comprise a hysteresis comparator, a PMOS tube used as a pull-up and an NMOS tube used as a pull-down, and correspondingly design a circuit connection relation, so that a preset interval can be set, and in the circuit structure of the embodiment of the invention, body Effect (Body Effect) can be avoided.
According to the touch display control device and the touch display device provided by the embodiment of the invention, the compensation control signals generated according to the reference voltage and the node voltage are used for gating the charging path and the discharging path, the saturated working area of the MOS tube is utilized, the current is large, and the pull-up or pull-down speed is higher.
Detailed Description
Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. The same reference numbers will be used throughout the drawings to refer to the same or like parts. For clarity, the various features of the drawings are not drawn to scale. Furthermore, some well-known portions may not be shown in the drawings.
The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. Numerous specific details of the invention, such as construction, materials, dimensions, processing techniques and technologies, may be set forth in the following description in order to provide a thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.
It will be understood that when a layer, an area, or a structure is described as being "on" or "over" another layer, another area, it can be referred to as being directly on the other layer, another area, or another layer or area can be included between the layer and the other layer, another area. And if the component is turned over, that layer, one region, will be "under" or "beneath" the other layer, another region.
Embodiments of the invention may be presented in a variety of forms, some of which are described below.
Fig. 2 and 3 show equivalent circuit diagrams of a display panel and a touch module, respectively, according to an embodiment of the invention.
In fig. 2, a liquid crystal display device is taken as an example, and a display panel 210 according to an embodiment of the present invention is shown. As shown in fig. 2, the display panel 210 includes a gate driving module 211, a source driving module 212, a plurality of thin film transistors T, and a plurality of pixel capacitances CLC formed between a pixel electrode and a common electrode. The plurality of thin film transistors T constitute an array. The gate driving module 211 is connected to the gates of the thin film transistors T of the corresponding rows via a plurality of gate scan lines G1 to Gm, respectively, for supplying gate voltages G1 to Gm in a scanning manner, thereby gating the thin film transistors of different rows in one image frame period. The source driving module 212 is connected to the sources of the thin film transistors T of the corresponding columns via the source data lines S1 to Sn, respectively, for providing gray scale voltages corresponding to gray scales to the thin film transistors T of the columns, respectively, when the thin film transistors T of the columns are turned on. Where m and n are natural numbers. The drains of the thin film transistors T are respectively connected to a corresponding one of the pixel capacitors CLC. In the gate state, the source driving module 212 applies a gray scale voltage to the pixel capacitor CLC via the source data line and the thin film transistor T. The voltage on the pixel capacitor CLC acts on the liquid crystal molecules, thereby changing the orientation of the liquid crystal molecules to achieve light transmittance corresponding to gray scale. In order to maintain the voltage between the refresh cycles of the pixel, the pixel capacitance CLC may be connected in parallel with the storage capacitance Cs to obtain a longer hold time.
In the present embodiment, the liquid crystal display device is taken as an example to show the internal structure and connection relation of the device, but the display device of the present invention is not limited to the liquid crystal display device.
In fig. 3, a capacitive touch is taken as an example, and a touch module 120 according to an embodiment of the invention is shown. As shown in fig. 3, the touch module 120 includes a touch driving module 121, a touch sensing module 122, and a plurality of sensing capacitors C formed between the driving electrodes and the sensing electrodes. The plurality of sensing capacitors C form an array. The touch driving module 121 is connected to the driving electrodes of all rows via scan lines TX1 to TXm for supplying driving signals in a scanning manner so that driving signals are sequentially supplied to the driving electrodes of different rows in one touch frame period. The touch sensing module 122 is connected to sensing electrodes of all columns via sensing lines RX1 to RXn, thereby receiving sensing signals of the corresponding columns. Where m and n are natural numbers. The touch driving module 121 generates, for example, an ac electric signal as an excitation signal, and the touch sensing module 122 receives, for example, a sensing signal in the form of an ac electric signal, detects a current value based on the sensing signal, and further obtains a capacitance value of an intersection between the driving electrode and the sensing electrode based on the magnitude of the current value, thereby determining whether a touch operation is generated at the point.
Although m and n are used as examples to describe the number of wires in the display panel and the touch module, it should be clear to those skilled in the art that the foregoing is only for convenience of description, and the number of wires in the display panel and the touch module in practical application is not necessarily the same. The structure and the working principle of the touch module are only described by taking the mutual capacitive touch as an example, but it should be clear to those skilled in the art that the above is only an example of the touch module, and the touch module of the present invention is not limited thereto.
Fig. 4 is a schematic diagram illustrating a connection structure inside a touch display device according to an embodiment of the invention. As shown in fig. 4, the touch display device includes a touch display control device 100 and a touch display panel 200.
The touch display control apparatus 100 may include a display control module 110 and a touch module 120. The display control module 110 may include the gate driving module 211 and the source driving module 212. The touch module 120 may include the touch driving module 121 and the touch sensing module 122 described above. The display control module 110 and the touch control module 120 may be integrated in a chip, for example, using TDDI technologies, and touch detection and display driving are performed in a time-sharing manner.
The touch display panel 200 may include a display panel 210 and a touch panel 220 integrated together, and the integration manner may be selected according to needs, such as but not limited to on-cell, in-cell, and the like. The display panel 210 is provided with the thin film transistor T, the pixel electrode, the common electrode and the corresponding wirings, and the touch panel 220 is provided with the excitation electrode, the sensing electrode and the corresponding wirings.
Fig. 5 is a schematic diagram illustrating a connection structure between a touch module and a touch panel according to an embodiment of the invention. As shown in fig. 5, the touch panel 220 according to the embodiment of the present invention is provided with a plurality of sensing electrodes Y and a plurality of exciting electrodes T in an array form, and the coupling capacitance between the adjacent exciting electrodes T and the sensing electrodes Y may be changed due to the touch, based on which the touch may be detected. The driving electrode T and the sensing electrode Y are respectively led out from the touch panel 220 via a plurality of touch lines TX and RX. Specifically, the driving electrode T is connected to the touch module 120 (specifically, to the touch driving module 121 in the touch module 120) via a plurality of scan lines TX so as to receive driving signals. The sensing electrode Y is connected to the touch module 120 (specifically, to the touch sensing module 122 in the touch module 120) via a plurality of sensing lines RX to provide a touch sensing signal thereto, and the plurality of sensing lines RX connected to the touch module 120 are different in length and different in impedance. The electrode shape and arrangement in fig. 5 are only examples, and the embodiments of the present disclosure are not limited thereto, and other forms of electrode shape and arrangement, such as triangle, E-shape, and other shapes, may be selected according to the actual application, and in addition, the exciting electrode T may be used as the exciting electrode, and the exciting electrode Y may be used as the exciting electrode.
Fig. 6 is a schematic structural diagram illustrating a connection between a sensing line and a touch display control device according to an embodiment of the invention. As shown in fig. 6, the touch display control device 100 includes a common voltage input module 101 and a compensation module 102. The common voltage input module 101 is used for providing a common voltage. The compensation module 102 is configured to gate the charging path or the discharging path to eliminate a node voltage offset at a common voltage input node P (hereinafter referred to as node P) when the voltage offset exceeds a preset value.
Specifically, the common voltage input module 101 is configured to access the common voltage signal VCOM to the touch display panel. The common voltage input module 101 includes a first input terminal (positive input terminal), a second input terminal (negative input terminal), and an output terminal. The first input end receives the common voltage signal VCOM, the second input end is connected with the output end, and the output end outputs the common voltage signal VCOM.
The voltages at different nodes P will have different voltage offsets due to the presence of the lead impedance R and the switch impedance R'. The compensation module 102 is configured to cancel the voltage offset of the node P when the voltage offset exceeds a preset value. The compensation module 102 includes a first input (positive input), a second input (negative input), and an output. The first input end (positive input end) is connected with the output end to form positive feedback; a second input (negative input) receives a reference common voltage signal vcom_ref; the output is connected to node P.
In a preferred embodiment of the present invention, the touch display control device 100 employs TDDI technology, and integrates the display control module 110 and the touch module 120. Also connected to the node P is a selection module MUX. The selection module MUX is configured to selectively access the touch module 120 and the common voltage signal VCOM to the touch display panel 200. For example, the selection module MUX may include a selection switch, which selects one of the touch detection channel and the common voltage signal VCOM to be connected to the sensing line RX of the touch display panel 200 under the control of a control signal. Specifically, in the touch detection stage, the selection module MUX accesses the touch detection channel to the touch display panel 200 under the action of the control signal, and the touch module 120 receives the multi-path touch sensing signals through the plurality of touch detection channels to perform touch detection and determine the touch position; in the display stage, the selection module accesses the common voltage signal VCOM to the sensing line RX of the touch display panel 200 under the action of the control signal, and in this stage, the display control module 110 drives the touch display panel 200 to display a picture.
In a preferred embodiment of the present invention, the output terminal of the common voltage input module 101 is connected to a plurality of sensing lines RX1, RX2, …, RXn of the touch display panel 200 through a selection module MUX, and forms nodes P1, P2, P3, …, pn (hereinafter referred to as node P) respectively. One compensation module 102 is connected at each node P, each compensation module 102 being configured to counteract a voltage offset coupled to a corresponding node P when the voltage offset exceeds a preset value.
The connection relationship between the modules of the present invention is described above by taking TDDI panels as an example, however, it should be clear to those skilled in the art that the above is only for convenience of description, and the touch display control device in practical application does not necessarily only use TDDI technology.
Fig. 7 shows a schematic circuit diagram of a compensation module according to an embodiment of the invention. As shown in fig. 7, the compensation module 102 includes a first transistor MP and a second transistor MN connected in series between a first supply voltage IOVCC and a second supply voltage VCL, and a hysteresis comparator 1021.
The first transistor MP includes a control electrode G1, a first electrode S1, and a second electrode D1; the second transistor MN includes a control electrode G2, a first electrode S2, and a second electrode D2. The first pole S1 of the first transistor MP and the first pole S2 of the second transistor MN receive the first supply voltage IOVCC and the second supply voltage VCL, respectively. The second pole D1 of the first transistor MP is connected to the second pole D2 of the second transistor MN and to the corresponding node P. The control electrode G1 of the first transistor MP is connected to the hysteresis comparator 1021, and receives the first control signal (PG signal); the gate G2 of the second transistor MN is connected to the hysteresis comparator 1021, and receives the second control signal (NG signal).
The hysteresis comparator 1021 includes a first input terminal (positive input terminal), a second input terminal (negative input terminal), and an output terminal. The first input terminal receives the common voltage signal VCOM, the second input terminal receives the reference common voltage signal vcom_ref (reference voltage), and the output terminal is used for outputting the control signal. The output terminal of the hysteresis comparator 1021 is connected to the first transistor and the second transistor, respectively, and the control signal may be divided into a first control path (PG path) connected to the first transistor and a second control path (NG path) connected to the second transistor.
In a preferred embodiment of the invention, the first supply voltage IOVCC is higher than the second supply voltage VCL. Preferably, the first supply voltage is a positive supply voltage, e.g. 1.8V, and the second supply voltage is a negative supply voltage, e.g. -3V. For example, the first supply voltage is between 1.8V-2V and the second supply voltage is between-3.3V- (-3V). For example, the first supply voltage is between 2V-3.6V and the second supply voltage is between-5V- (-3V). The actual voltage may be determined based on the circuit requirements.
In this embodiment, the first transistor MP includes a P-type MOS transistor, the second transistor MN includes an N-type MOS transistor, the first electrode is a source electrode, the second electrode is a drain electrode, and the control electrode is a gate electrode.
In the above embodiment, the compensation control signal generated according to the reference voltage and the node voltage is used to gate the charging path and the discharging path, and the saturated operating region of the MOS transistor is utilized, so that the current is large, and the pull-up or pull-down speed is faster.
Fig. 8 is a circuit schematic diagram illustrating a connection structure between a touch display panel and a touch display control device according to an embodiment of the invention. Fig. 9 is a schematic diagram illustrating a control principle of a control method of a touch display device according to an embodiment of the invention. The operation principle of the touch display control apparatus 100 will be described with reference to fig. 7, 8 and 9.
The common voltage input module 101 is configured to access the common voltage signal VCOM to the touch display panel. In the display stage, the touch display control device 100 accesses the common voltage signal VCOM to the sensing lines RX1, RX2, …, RXn on the touch display panel 200. When the common voltage signal VCOM is greater than the sum of the reference common voltage signal vcom_ref and the upper offset voltage threshold (os+), the output terminal of the hysteresis comparator 1021 outputs a second control signal, which is output to the control electrodes of the first transistor MP and the second transistor MN via the first control path and the second control path, respectively. Under the control of the second control signal, the first transistor MP is not turned on, the second transistor MN is turned on (i.e., the bleeder path is gated), the common voltage signal VCOM at the node P is pulled down, and the common voltage signal VCOM is accelerated to return to the reference common voltage signal vcom_ref (as shown in fig. 9 (b)); when the common voltage signal VCOM is smaller than the difference between the reference common voltage signal vcom_ref and the lower offset voltage threshold (OS-) the output terminal of the hysteresis comparator 1021 outputs a first control signal, which is output to the control electrodes of the first transistor MP and the second transistor MN via the first control path and the second control path, respectively. Under the control of the first control signal, the second transistor MN is not turned on, the first transistor MP is turned on (i.e. the charging path is gated), the common voltage signal VCOM at the node P is pulled up, and the common voltage signal VCOM is accelerated to return to the reference common voltage signal vcom_ref (as shown in fig. 9 (a)).
In the above-described embodiment, the magnitudes of the upper offset voltage threshold (os+) and the lower offset voltage threshold (OS-) may be set by setting the hysteresis comparator according to circumstances. When the threshold value is set to be smaller, the voltage fluctuation range at the node P is smaller, and the better the effect of pulling the common voltage signal back to the reference common voltage signal is; when set to a larger threshold, the voltage fluctuation range at the node P is larger.
In the above embodiment, the hysteresis comparator, the PMOS transistor used as the pull-up, and the NMOS transistor used as the pull-down have a special circuit connection relationship, so that the Body Effect (Body Effect) can be avoided.
From the above analysis, it can be seen that the hysteresis comparator 1021 has two threshold voltages. When the input changes in one direction, the output jumps only once. When the input is changed from big to small, the threshold voltage is correspondingly small; when the input is changed from small to large, the threshold voltage is correspondingly large. Between the two threshold voltages, the output remains the original output. The compensation module only changes a control signal for eliminating voltage deviation once in the process that the node voltage unidirectionally passes through a preset interval formed by an upper limit threshold value and a lower limit threshold value.
In a preferred embodiment of the present invention, the hysteresis comparator 1021 receives an initial common voltage signal VCOM and a reference common voltage signal vcom_ref. When the initial common voltage signal VCOM is between the sum of the reference common voltage signal vcom_ref and the upper offset voltage threshold (os+) and the difference between the reference common voltage signal vcom_ref and the lower offset voltage threshold (OS-) the output terminal of the hysteresis comparator 1021 does not output a signal, and both the first transistor MP and the second transistor MN are in the off state. Before switching from the touch stage to the display stage, the hysteresis comparator 1021 is reset, i.e., the output of the hysteresis comparator 1021 no longer outputs a signal. When the common voltage signal VCOM exceeds a preset interval, the hysteresis comparator 1021 outputs a corresponding control signal.
Fig. 10 is a schematic diagram showing a voltage signal at a node P when a touch display device is switched from a touch stage to a display stage according to an embodiment of the invention. In the figure, the abscissa represents time, the ordinate represents voltage, the broken line represents the voltage signal at the node P using the conventional technique, and the solid line represents the voltage signal at the node P according to the embodiment of the present invention. As shown in fig. 10, in the conventional technology, when switching from the touch stage to the display stage, VCOM is connected to the sensing line RX, and the voltage at the node P rapidly rises from the voltage VCOM to the voltage V2 from t0 until t2 falls back to the voltage VCOM. In the embodiment of the present invention, after the voltage at the node P rises to V1, the voltage drops back to the voltage VCOM at time t1. Compared with the prior art, the voltage fluctuation range of the device at the node P is smaller, the voltage at the node P can be stabilized to a desired level more quickly, the voltage at the node P can be returned to the common voltage VCOM quickly in a short time, the voltage on each induction electrode connecting line is stabilized in a desired range, and the influence on a display picture is reduced.
In an embodiment of the invention, a touch display chip is provided, which includes the touch display control device 100 described above.
In one embodiment of the present invention, there is provided a touch display device including: the touch display panel comprises a plurality of touch electrodes, and the plurality of touch electrodes are led out from the touch display panel through a plurality of touch lines; and the touch display control device 100, wherein the touch module is connected to a plurality of touch lines, each touch detection channel is connected to a corresponding touch line, and a connection node of the touch detection channel and the touch line is connected to the compensation module.
It should be noted that in this document relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Embodiments in accordance with the present invention, as described above, are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and the full scope and equivalents thereof.