Capacitance compensation method of display touch panel and touch sensing and display driving integrated circuit using same

Abstract

The invention relates to a capacitance compensation method of a display touch panel and a touch sensing and display driving integrated circuit using the same. The capacitance compensation method of the display touch panel comprises the steps that a touch sensing and display driving circuit is provided, and the touch sensing and display driving circuit comprises a plurality of display driving pins and a plurality of touch sensing pins; the plurality of touch sensing pins are configured with a compensation capacitor; when a specific touch sensing pin of the plurality of touch sensing pins performs touch sensing, a first pulse wave is output aiming at the plurality of display driving pins; inputting a second pulse wave to one end of the compensation capacitor after delaying for a preset time; and detecting a capacitance change by the specific touch sensing pin during an overlapping period of the first pulse wave and the second pulse wave.

Description

Technical Field

[0001] The present invention relates to a touch sensing and display driving technology, and in particular to a capacitance compensation method for a display touch panel and a touch sensing and display driving integrated circuit using the same. Background Art

[0002] In embedded display touch sensing panels, the display driver common voltage electrode (VCOM) is usually a special electrode that plays the role of a neutral potential regulator when the display screen is displaying. When the display is not driven, the display driver common voltage electrode will be used as a touch electrode. The display panel drive circuit is divided into data lines (source lines) and scan lines (gate lines). These lines will generate many internal parasitic capacitances relative to the display driver common voltage electrode or the panel. The total capacitance of these parasitics is much larger than the touch capacitance change value to be detected by the touch sensing unit.

[0003] Since the display panel drive circuit itself contains many capacitors, when a finger or other conductor is close to the display touch panel, a new capacitor will be formed, called a sensing capacitor. This sensing capacitor will interact with the capacitor in the display panel drive circuit to form an input circuit. Since the capacitor is sensitive to frequency, the stray capacitance of the display panel drive circuit is closely related to the impact of touch sensing.

[0004] As the resolution of display touch panels increases, the frequency of touch sensing increases. When the frequency is high, the capacitance of the drive circuit will have a significant impact on touch sensing. This will cause the sensitivity of the display touch panel to decrease, or cause problems such as false touches. Therefore, how to offset the parasitic capacitance on the panel is a key factor in reducing the touch function area and improving performance. Summary of the invention

[0005] The present invention provides a capacitance compensation method for a display touch panel and a touch sensing and display driving integrated circuit using the same, which is used to reduce the influence of the stray capacitance of the panel on the touch control without increasing the internal compensation capacitance of the integrated circuit as much as possible, increase the sensitivity of the touch control, reduce the area of ​​the integrated circuit, and reduce the cost.

[0006] An embodiment of the present invention provides a capacitance compensation method for a display touch panel, and the capacitance compensation method for the display touch panel includes the following steps: providing a touch sensing and display driving circuit, wherein the touch sensing and display driving circuit includes a plurality of display driving pins and a plurality of touch sensing pins; the plurality of touch sensing pins are configured with a compensation capacitor; when a specific touch sensing pin among the plurality of touch sensing pins performs touch sensing, a first pulse is first output for the plurality of display driving pins; after a delay of a predetermined time, a second pulse is input to one end of the compensation capacitor; and during the period when the first pulse and the second pulse overlap, the capacitance change of the specific touch sensing pin is detected.

[0007] The embodiment of the present invention further provides a touch sensing and display driving integrated circuit, which includes a plurality of display driving pins, a plurality of touch sensing pins and a plurality of touch sensing circuits. The plurality of touch sensing pins are configured with a compensation capacitor. The plurality of touch sensing circuits are coupled to the touch sensing pins. When a specific touch sensing pin among the plurality of touch sensing pins performs touch sensing, a first pulse is first output for the plurality of display driving pins. After a delay of a predetermined time, a second pulse is input to one end of the compensation capacitor. During the overlap period of the first pulse and the second pulse, the touch sensing circuit coupled to the specific touch sensing pin detects the capacitance change.

[0008] According to the capacitance compensation method of the display touch panel and the touch sensing and display driving integrated circuit using the same described in the preferred embodiment of the present invention, one end of the compensation capacitor coupled to the specific touch sensing pin is coupled to the specific touch sensing pin, and the other end of the compensation capacitor coupled to the specific touch sensing pin receives the second pulse.

[0009] According to the capacitance compensation method of the display touch panel and the touch sensing and display driver integrated circuit using the same described in the preferred embodiment of the present invention, the above-mentioned specific touch sensing pin is coupled to a touch sensing circuit, wherein the touch sensing circuit includes an amplifier circuit, a first switch circuit and a second switch circuit. The amplifier circuit includes a first input terminal, a second input terminal and an output terminal, wherein the first input terminal of the amplifier circuit is coupled to the compensation capacitor, and the second input terminal of the amplifier circuit is coupled to a reference voltage. The first switch circuit is coupled between the first input terminal of the amplifier circuit and the compensation capacitor. The second switch circuit is coupled between the output terminal of the amplifier circuit and the first input terminal of the amplifier circuit. When the touch sensing circuit is working, the first switch circuit is turned on and the second switch circuit is turned off, and when the touch sensing circuit is not working, the first switch circuit is turned off and the second switch circuit is turned on.

[0010] According to the capacitance compensation method of the display touch panel and the touch sensing and display driving integrated circuit using the same according to the preferred embodiment of the present invention, the voltage of the first pulse in the first state and the voltage of the second pulse in the first state are equal to the reference voltage.

[0011] In summary, the embodiment of the present invention uses a first pulse wave to output to the driving pin during touch detection, thereby charging the driving circuit and reducing the influence of the stray capacitance of the driving circuit on touch sensing. In addition, a second pulse wave is output at the other end of the compensation capacitor to compensate the stray capacitance of the driving circuit again. And because in the embodiment of the present invention, a phase difference is given between the first pulse wave received by the driving circuit and the second pulse wave received by the compensation capacitor so that the two are not output at the same time, the compensation capacitor can use a relatively small capacitor. In addition to reducing the influence of the stray capacitance of the panel on touch control and increasing the sensitivity of touch control, the embodiment of the present invention can also reduce the area of ​​the integrated circuit and reduce the cost.

[0012] In order to further understand the technology, means and effects of the present invention, reference may be made to the following detailed description and accompanying drawings, so that the purpose, features and concepts of the present invention can be thoroughly and specifically understood. However, the following detailed description and accompanying drawings are only used for reference and explanation of the implementation of the present invention, and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are provided to enable those skilled in the art to further understand the present invention and are incorporated into and constitute a part of the specification of the present invention. The accompanying drawings illustrate exemplary embodiments of the present invention and are used to explain the principles of the present invention together with the description of the present invention.

[0014] Figure 1 FIG. 1 is a block diagram of a touch sensing and display driving integrated circuit according to a preferred embodiment of the present invention.

[0015] Figure 2 FIG. 4 is a circuit diagram of a touch sensing and display driving integrated circuit according to a preferred embodiment of the present invention.

[0016] Figure 3 FIG. 1 is an operation waveform diagram of a display driver and touch sensing integrated circuit according to a preferred embodiment of the present invention.

[0017] Figure 4 FIG. 1 is an operation waveform diagram of a display driver and touch sensing integrated circuit according to a preferred embodiment of the present invention.

[0018] Figure 5 The figure is a flow chart of a capacitance compensation method for a display touch panel according to a preferred embodiment of the present invention.

[0019] Explanation of symbols:

[0020] 101: Display touch panel

[0021] 102: Display driver and touch sensing integrated circuit

[0022] 10: Scan Line

[0023] 11: Data cable

[0024] 12: Multiple touch sensing lines

[0025] 201: Display driver pin

[0026] 202: Scan drive pin

[0027] 203: Touch sensor pin

[0028] 204: Touch sensing circuit

[0029] 205: Multi-tasking circuit

[0030] Csx-gip: parasitic capacitance caused by gate drive line

[0031] Csx-sd: parasitic capacitance caused by data drive line

[0032] 21: Amplifier circuit

[0033] 22: First switch circuit

[0034] 23: Second switch circuit

[0035] CFB: Feedback Capacitor

[0036] CB: Compensation capacitor

[0037] VREF: reference voltage

[0038] VR: Touch reference voltage

[0039] Tc: one end of compensation capacitor CB

[0040] S500-S507: Process steps of a capacitance compensation method for a display touch panel according to a preferred embodiment of the present invention DETAILED DESCRIPTION

[0041] Reference will now be made in detail to exemplary embodiments of the present invention, which are illustrated in the accompanying drawings. Where possible, the same component symbols are used in the drawings and the specification to refer to the same or similar components. In addition, the exemplary embodiments are only one of the implementation methods of the design concept of the present invention, and the following examples are not intended to limit the present invention.

[0042] Figure 1This is a circuit block diagram of a display touch control system according to a preferred embodiment of the present invention. Figure 1 , the display touch control system includes a display touch control panel 101 and a touch display driving integrated circuit (TDDI IC) 102. The above-mentioned touch sensing and display driving integrated circuit can also be called a touch display integrated circuit (IDC IC). The display touch control panel 101 has a plurality of scan lines 10, a plurality of data lines 11 and a plurality of touch sensing lines 12. In this embodiment, the driving circuit of the display panel and the touch sensing circuit are integrated in the touch sensing and display driving integrated circuit 102.

[0043] Figure 2 This is a circuit diagram of a touch sensing and display driving integrated circuit 102 according to a preferred embodiment of the present invention. Figure 2 In this embodiment, the touch sensing and display driving integrated circuit 102 includes a display driving pin 201, a scan driving pin 202, a touch sensing pin 203, a touch sensing circuit 204 and a multi-task circuit 205. In this embodiment, the display driving pin 201, the scan driving pin 202, the touch sensing pin 203 and the touch sensing circuit 204 are only shown as one group. However, a person skilled in the art should know that there are multiple groups of circuits actually used, which are not described here. Furthermore, since the touch sensing circuit 204 can detect different touch sensing electrodes one by one by using a time-sharing multitasking method when the present embodiment is actually applied, a multi-tasking circuit 205 is additionally provided to detect multiple touch sensing electrodes in a time-sharing manner. However, a person skilled in the art should know that if the present embodiment does not use a time-sharing multitasking method, the multi-tasking circuit 205 can also be omitted.

[0044] In the above embodiment, each touch sensing electrode on the panel is regarded as a common electrode voltage VCOM during the display driving period. During the touch sensing period, each of the above driving lines (including the gate driving line and the data driving line) will generate parasitic capacitance between the touch sensing related circuits, which are simplified as Csx-gip and Csx-sd in the figure, respectively, where Csx-gip represents the parasitic capacitance caused by the gate driving line, and Csx-sd represents the parasitic capacitance caused by the data driving line. The parasitic capacitance Csx-gip caused by the gate driving line and the parasitic capacitance Csx-sd caused by the data driving line will affect the operation of the touch sensing circuit 204.

[0045] In this embodiment, the touch sensing circuit 204 is implemented in the form of an integrator, for example. In this embodiment, the touch sensing circuit 204 includes an amplifier circuit 21, a first switch circuit 22, a second switch circuit 23, and a feedback capacitor CFB. The amplifier circuit 21 includes a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal of the amplifier circuit 21 is coupled to the compensation capacitor CB, and the second input terminal of the amplifier circuit 21 is coupled to a touch reference voltage VR. The first switch circuit 22 is coupled between the first input terminal of the amplifier circuit 21 and the compensation capacitor CB. The second switch circuit 23 and the feedback capacitor CFB are both coupled in parallel between the output terminal of the amplifier circuit 21 and the first input terminal of the amplifier circuit 21.

[0046] Figure 3 This is an operation waveform diagram of the touch sensing and display driving integrated circuit 102 of a preferred embodiment of the present invention. Figure 3 , in the initial state T1, the second switch circuit 23 is in the on state. In order to allow the touch sensing circuit 204 to operate normally, in this embodiment, the touch sensing and display driving integrated circuit 102 will first output a first pulse VP to the display driving pin 201 and the scan driving pin 202 during the touch sensing period T2. The voltage of this first pulse VP is the reference voltage VREF, which is used to reduce or eliminate the effect of the parasitic capacitance Csx-gip caused by the gate driving line and the parasitic capacitance Csx-sd caused by the data driving line. At this time, the multitasking circuit 205 is turned on, and the second switch circuit 23 is turned off, and the first switch circuit 22 is turned on. In addition, a predetermined time ΔT after the reference voltage VREF is output to the display driving pin 201 and the scan driving pin 202, a second pulse VCB is also output to the other end Tc of the compensation capacitor CB. The voltage of this second pulse VCB is the reference voltage VREF. In this way, the touch sensing circuit 204 detects whether there is a capacitance change in the touch electrode.

[0047] In the above embodiment, the display touch sensing and display driver integrated circuit 102 outputs a display control signal such as a full drive signal (such as the above reference voltage VREF) during the touch sensing period, and stores and releases charges in the parasitic capacitor to compensate and reduce the adverse effects of the parasitic capacitor Csx, and outputs the reference voltage VREF to the compensation capacitor CB after a predetermined time, so the compensation capacitor CB required to be designed inside the touch sensing and display driver integrated circuit 102 can be greatly reduced. Generally speaking, most of the components that occupy a relatively large area inside the integrated circuit are capacitors. This embodiment reduces the capacitance value required for the compensation capacitor CB during the design to reduce the area of ​​the capacitor, which can greatly reduce the overall area and cost of the integrated circuit. In addition, in this embodiment, the same reference voltage VREF is provided to the display driver pin 201, the scan driver pin 202 and the compensation capacitor CB during the touch sensing period. However, those skilled in the art should know that different voltage values ​​may be provided to the display driver pin 201, the scan driver pin 202 and the compensation capacitor CB during the touch sensing period. As long as a high voltage is applied to reduce the interference of the parasitic capacitance during the touch sensing period, it should be within the scope of the present invention.

[0048] Figure 4 This is an operation waveform diagram of the touch sensing and display driving integrated circuit 102 of a preferred embodiment of the present invention. Figure 3 as well as Figure 4 In this embodiment, the touch sensing is divided into a positive half cycle and a negative half cycle. In the positive half cycle, the driving method is the same as above, so it is not repeated here. However, in the negative half cycle, after the T1 time ends, the first pulse VP changes from a high voltage to a low voltage, and after a predetermined time ΔT, the second pulse VCB changes from a high voltage to a low voltage.

[0049] Above Figure 3 and Figure 4 It can be seen from the preferred embodiment that a phase difference is given between the first pulse wave VP and the second pulse wave VCB, and touch detection is performed during the overlapping period. However, the present invention is not limited to this preferred embodiment.

[0050] The above embodiments can be summarized into a capacitance compensation method for a display touch panel. Figure 5 This is a flow chart of a capacitance compensation method for a display touch panel according to a preferred embodiment of the present invention. Figure 5 The capacitance compensation method of the display touch panel includes the following steps:

[0051] Step S500: Start.

[0052] Step S501: providing a touch sensing and display driving circuit, wherein the touch sensing and display driving circuit comprises a plurality of display driving pins and a plurality of touch sensing pins.

[0053] Step S502: providing a compensation capacitor to be disposed at the plurality of touch sensing pins.

[0054] Step S503: Determine whether to perform touch sensing. If touch sensing is performed, proceed to step S404.

[0055] Step S504: Output a first pulse to the plurality of display driving pins. When the touch sensing pins perform touch sensing, firstly output a full drive voltage, such as the reference voltage VREF, to the display driving pins 201 and the scan driving pins 202 .

[0056] Step S505: Delay a predetermined time and input a second pulse to one end of the compensation capacitor. As in the above embodiment, after a predetermined time ΔT, the second pulse VCB is output to the other end Tc of the compensation capacitor CB.

[0057] Step S506: Detect capacitance change during the overlap period of the first pulse wave and the second pulse wave. Figure 3 As shown, by detecting the change in charge Qf during this period, the change in capacitance of the touch electrode can be determined.

[0058] Step S507: End.

[0059] In summary, the embodiment of the present invention uses a first pulse wave to output to the driving pin during touch detection, thereby charging the driving circuit and reducing the influence of the stray capacitance of the driving circuit on touch sensing. In addition, a second pulse wave is output at the other end of the compensation capacitor to compensate the stray capacitance of the driving circuit again. In addition, in the embodiment of the present invention, a phase difference is given between the first pulse wave received by the driving circuit and the second pulse wave received by the compensation capacitor so that the two are not output at the same time, so the compensation capacitor can use a relatively small capacitor. Therefore, the embodiment of the present invention can not only reduce the influence of the stray capacitance of the panel on touch control, increase the sensitivity of touch control, but also reduce the area of ​​the integrated circuit.

[0060] It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in view thereof will be suggested to those skilled in the art and are to be included within the spirit and scope of the present application and the scope of the appended claims.

Claims

1. A capacitance compensation method for a display touch panel, characterized in that: include: A touch sensing and display driving circuit is provided, wherein the touch sensing and display driving circuit comprises a plurality of display driving pins and a plurality of touch sensing pins; The plurality of touch sensing pins are configured with a compensation capacitor; When a specific touch sensing pin among the plurality of touch sensing pins performs touch sensing, it includes: Firstly, a first pulse is outputted for the plurality of display driving pins; Delaying a predetermined time, inputting a second pulse wave to one end of the compensation capacitor; and During the overlap period of the first pulse wave and the second pulse wave, the capacitance change of the specific touch sensing pin is detected.

2. The capacitance compensation method for a display touch panel according to claim 1, wherein: One end of the compensation capacitor coupled to the specific touch sensing pin is coupled to the specific touch sensing pin, and the other end of the compensation capacitor coupled to the specific touch sensing pin receives the second pulse.

3. The capacitance compensation method for a display touch panel according to claim 1, wherein: The specific touch sensing pin is coupled to a touch sensing circuit, wherein the touch sensing circuit includes: An amplifier circuit comprises a first input terminal, a second input terminal and an output terminal, wherein the first input terminal of the amplifier circuit is coupled to the compensation capacitor, and the second input terminal of the amplifier circuit is coupled to a reference voltage; a first switch circuit coupled between the first input terminal of the amplifier circuit and the compensation capacitor; and a second switch circuit coupled between the output terminal of the amplifier circuit and the first input terminal of the amplifier circuit; When the touch sensing circuit is working, the first switch circuit is turned on and the second switch circuit is turned off. When the touch sensing circuit is not working, the first switch circuit is turned off and the second switch circuit is turned on.

4. The capacitance compensation method for a display touch panel according to claim 3, wherein: The voltage of the first pulse in the first state and the voltage of the second pulse in the first state are equal to the reference voltage.

5. The capacitance compensation method for a display touch panel according to claim 1, wherein: The first pulse wave and the second pulse wave have a phase difference.

6. A touch sensing and display driving integrated circuit, characterized in that: include: Multiple display driver pins; A plurality of touch sensing pins, wherein each of the plurality of touch sensing pins is configured with a compensation capacitor; and A plurality of touch sensing circuits coupled to the touch sensing pins; When a specific touch sensing pin among the plurality of touch sensing pins performs touch sensing, a first pulse is output to the plurality of display driving pins, and a second pulse is input to one end of the compensation capacitor after a delay of a predetermined time. During the overlap period of the first pulse and the second pulse, the touch sensing circuit coupled to the specific touch sensing pin detects the capacitance change.

7. The touch sensing and display driving integrated circuit according to claim 5, wherein: One end of the compensation capacitor coupled to the specific touch sensing pin is coupled to the specific touch sensing pin, and the other end of the compensation capacitor coupled to the specific touch sensing pin receives the second pulse.

8. The touch sensing and display driving integrated circuit as claimed in claim 5, wherein: The touch sensing circuit comprises: An amplifier circuit comprises a first input terminal, a second input terminal and an output terminal, wherein the first input terminal of the amplifier circuit is coupled to the compensation capacitor, and the second input terminal of the amplifier circuit is coupled to a reference voltage; a first switch circuit coupled between the first input terminal of the amplifier circuit and the compensation capacitor; and a second switch circuit coupled between the output terminal of the amplifier circuit and the first input terminal of the amplifier circuit; When the touch sensing circuit is working, the first switch circuit is turned on and the second switch circuit is turned off. When the touch sensing circuit is not working, the first switch circuit is turned off and the second switch circuit is turned on.

9. The touch sensing and display driving integrated circuit as claimed in claim 5, wherein: The voltage of the first pulse in the first state and the voltage of the second pulse in the first state are equal to the reference voltage.

10. The touch sensing and display driving integrated circuit according to claim 7, wherein: A multi-task circuit is also included between the first switch circuit and the corresponding plurality of touch sensing pins, for switching the plurality of touch sensing pins to perform time-sharing multi-task touch detection.

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