A space-saving driving circuit, method, and touch display driver chip

Abstract

This invention provides a space-saving driving circuit, method, and touch display driver chip. The driving circuit includes a common electrode driving circuit. During the display driving period, the common electrode driving circuit outputs a common voltage to drive the common electrode. During the touch sensing period, the common electrode driving circuit outputs a compensation voltage to drive a compensation capacitor, which compensates for parasitic capacitance on the sensing path. By using the common electrode driving circuit to drive the compensation capacitor during the touch sensing period, this invention eliminates the need for an additional driving circuit for the compensation capacitor, reducing the complexity and circuit area of ​​the driving circuit on the touch display driver chip.

Description

Technical Field

[0001] This invention relates to the field of driver chip technology, and in particular to a space-saving driver circuit, method, and touch display driver chip. Prior Technology

[0002] Display panels are widely used in consumer electronics such as mobile phones, watches, and tablets. To reduce costs, touch display driver chips have developed rapidly. They integrate the common electrode driving circuit for display and the touch sensing circuit for touch control into the touch display driver chip, thereby achieving an integrated design of touch and display.

[0003] Specifically, the common electrode in the display panel is driven by the common electrode driving circuit during the display period, and the sensing electrode in the display panel is driven by the touch sensing circuit during the touch sensing period. However, due to the parasitic capacitance in the signal traces within the display panel and the chip, the sensing signal in the touch sensing circuit is prone to saturation. Therefore, in the prior art, compensation capacitors are usually used to offset the additional sensing signal introduced by the parasitic capacitance. This requires adding an additional driving circuit for driving the compensation capacitor within the touch display driver chip, thereby increasing the complexity and circuit area of ​​the driving circuit on the touch display driver chip. Summary of the Invention

[0004] The purpose of this invention is to provide an area-saving driving circuit, method, and touch display driver chip, which reduces the complexity and circuit area of ​​the driving circuit on the touch display driver chip.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] A method for saving driving circuit area, the driving circuit including a common electrode driving circuit, wherein during the display driving period, the common electrode driving circuit outputs a common voltage for driving the common electrode, and during the touch sensing period, the common electrode driving circuit outputs a compensation voltage for driving a compensation capacitor, the compensation capacitor being used to compensate for parasitic capacitance on the sensing path.

[0007] Optionally, the driving circuit includes a touch sensing circuit, the first end of the compensation capacitor is connected to the compensation node of the touch sensing circuit, and the second end of the compensation capacitor is connected to the voltage output terminal of the common electrode driving circuit.

[0008] Optionally, the first terminal of the compensation capacitor is also grounded via a first switch.

[0009] Optionally, during the touch sensing period, the first switch disconnects the ground connection of the compensation capacitor, and the common electrode driving circuit outputs a compensation voltage to drive the compensation capacitor so that the compensation capacitor provides capacitance compensation to the sensing path; during the display driving period, the first switch connects the ground connection of the compensation capacitor so that the compensation capacitor is reused as a storage capacitor to maintain the stability of the common voltage output by the common electrode driving circuit.

[0010] Optionally, the first end of the compensation capacitor is connected to the compensation node of the touch sensing circuit through a second switch. During the display driving period, the second switch disconnects the compensation capacitor from the compensation node of the touch sensing circuit to avoid the compensation capacitor affecting the voltage of the compensation node.

[0011] Optionally, the voltage output terminal of the common electrode driving circuit is connected to a storage capacitor through a third switch. During the display driving period, the third switch connects the common electrode driving circuit and the storage capacitor to maintain the stability of the common voltage. During the touch sensing period, the third switch disconnects the common electrode driving circuit and the storage capacitor to prevent the compensation voltage output by the common electrode driving circuit from charging and discharging the storage capacitor.

[0012] An area-saving drive circuit includes:

[0013] A multiplexer is used to select the output common voltage to drive the common electrode during the display driving period, and to select the output touch voltage to drive the sensing electrode during the touch sensing period;

[0014] Compensation capacitors are used to compensate for parasitic capacitances in the sensing path.

[0015] During the display driving period, the common electrode driving circuit is allowed by the multiplexer to output a common voltage to drive the common electrode. During the touch sensing period, the common electrode driving circuit outputs a compensation voltage to drive the compensation capacitor.

[0016] Optionally, it further includes: a touch sensing circuit, wherein during the touch sensing period, the touch sensing circuit is allowed by the multiplexer to output a touch voltage to drive the sensing electrode.

[0017] Optionally, the touch sensing circuit includes:

[0018] The second sub-drive module is used to output the sensing waveform and convert the sensed capacitance into a current signal;

[0019] The third sub-driving module is used to convert the current signal into a voltage signal.

[0020] Optionally, a compensation node is provided at the input end of the third sub-driving module, and the first end of the compensation capacitor is connected to the touch sensing circuit through the compensation node.

[0021] Optionally, the common electrode driving circuit includes a first sub-driving module, which outputs a common voltage during the display driving period or a compensation voltage during the touch sensing period.

[0022] Optionally, the second terminal of the compensation capacitor is connected to the voltage output terminal of the common electrode driving circuit.

[0023] Optionally, the first terminal of the compensation capacitor is also connected to ground via a first switch.

[0024] Optionally, the first end of the compensation capacitor is directly connected to the compensation node, or it is connected to the compensation node through a second switch.

[0025] Optionally, the voltage output terminal of the common electrode driving circuit is connected to a storage capacitor via a third switch.

[0026] Optionally, the sensing electrode can be reused as the common electrode.

[0027] A touch display driver chip includes an area-saving driver circuit as described in any of the above.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] By reusing the common electrode driving circuit as the driving circuit for the compensation capacitor during the touch sensing period, the driving circuit no longer needs to set up an additional driving circuit for each compensation capacitor, thereby reducing the complexity and circuit area of ​​the driving circuit;

[0030] During the display driving period, the ground connection of the compensation capacitor is turned on by the first switch, so that the compensation capacitor can be reused as a storage capacitor to maintain the stability of the common voltage output of the common electrode driving circuit. This allows the common electrode driving circuit to provide a more stable voltage hold, thereby ensuring the stability and quality of the displayed image.

[0031] During the display driving period, the connection between the compensation capacitor and the compensation node of the touch sensing circuit is disconnected by the second switch. During the touch sensing period, the connection between the compensation capacitor and the compensation node of the touch sensing circuit is turned on by the second switch. This avoids the compensation capacitor affecting the voltage of the compensation node, thereby reducing the impact on the preparation state of the touch sensing circuit before sensing. This allows the input and output of the touch sensing circuit to be reset to the corresponding common-mode level before sensing begins, improving touch sensing efficiency.

[0032] A third switch connects the voltage output terminal of the common electrode driving circuit to a storage capacitor. During the display driving period, the third switch connects the common electrode driving circuit and the storage capacitor to maintain the stability of the common voltage. During the touch sensing period, the third switch disconnects the common electrode driving circuit from the storage capacitor to avoid the compensation voltage output by the common electrode driving circuit from generating additional power consumption for the charging and discharging of the storage capacitor. Simple Explanation of the Diagram

[0033] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings described below are one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 is a structural diagram of the driving circuit on an existing touch display driver chip;

[0035] Figure 2 is a structural diagram of a first type of driving circuit on a touch display driving chip according to an embodiment of the present invention;

[0036] Figure 3 is a structural diagram of a second type of driving circuit on a touch display driving chip according to an embodiment of the present invention;

[0037] Figure 4 is a structural diagram of a third type of driving circuit on a touch display driving chip according to an embodiment of the present invention;

[0038] Figure 5 is a structural diagram of a fourth type of driving circuit on a touch display driver chip provided in an embodiment of the present invention. Implementation

[0039] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the proposed solution of the present invention. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clearly illustrate the embodiments of the present invention. Please refer to the drawings to make the objectives, features, and advantages of the present invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to aid those skilled in the art, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the present invention, should still fall within the scope of the technical content disclosed in the present invention.

[0040] First, the working principle of existing driving circuits used for touch sensing and display is introduced. Figure 1 is a schematic diagram of the driving circuit in an existing touch display driver chip. The common electrode in the touch display driver chip is divided into many small blocks as sensing electrodes. The specific location of the touch point can be determined by detecting the change in capacitance of each sensing electrode. Only one sensing electrode SX is shown in Figure 1. <k>During the display driving period, the common electrode is overridden and driven by the common voltage output from the common electrode driving circuit 100 selected by the multiplexer MUX. During the touch sensing period, the sensing electrode is driven by the touch voltage output from the touch sensing circuit 200 selected by the multiplexer MUX. Operational amplifier OP1 in the touch sensing circuit 200 outputs the touch voltage based on the sensing signal VSX, and converts the detected capacitance into a current signal Isense, which is then sent to operational amplifier OP2. Operational amplifier OP2 converts the input current into a voltage and compares it with a reference voltage Vref to obtain two differential voltage signals VOP. <k>and VON <k>And output. Isense reflects the magnitude of all capacitances along the sensing path, of which only the touch capacitance CT is an effective signal used for detection and judgment. The sensing amount caused by parasitic capacitances, such as Csp from the panel and CSC from the signal traces inside the chip, is not only unrelated to touch, but also saturates the signal of operational amplifier OP2. Therefore, a compensation capacitor Ccomp is introduced at the input of operational amplifier OP2 to generate a reverse current Icomp to cancel the sensing amount caused by parasitic capacitance. At the same time, a corresponding additional driving circuit 300 is also added. The operational amplifier OP3 in the additional driving circuit 300 outputs a compensation voltage according to the compensation waveform Vcomp, which is opposite to the sensing signal Vsx, to drive the compensation capacitor Ccomp. The compensation waveform Vcomp also requires an additional reference circuit to generate. Since each touch sensing circuit 200 needs a compensation capacitor Ccomp for compensation, each touch sensing circuit 200 needs to be set with a corresponding additional driving circuit 300, which leads to high complexity and increased area of ​​the existing driving circuit.

[0041] To address the aforementioned shortcomings, this invention, based on the time-division multiplexing characteristic of touch display driver chips, reuses the common electrode driving circuit 100 to drive the common electrode and compensation capacitor Ccomp in a time-division multiplexing manner, thereby eliminating the need for an additional driving circuit 300 for driving the compensation capacitor Ccomp, and thus reducing the complexity and circuit area of ​​the driving circuit on the touch display driver chip.

[0042] Based on the above-mentioned inventive concept, this invention provides a method for saving driving circuit area. Referring to Figure 2, the driving circuit includes a common electrode driving circuit 100. During the display driving period, the common electrode driving circuit 100 outputs a common voltage to drive the common electrode. During the touch sensing period, the common electrode driving circuit 100 outputs a compensation voltage to drive the compensation capacitor Ccomp. The compensation capacitor Ccomp is used to compensate for parasitic capacitance on the sensing path. By reusing the common electrode driving circuit 100 as the driving circuit for the compensation capacitor Ccomp during the touch sensing period, the driving circuit no longer needs to set an additional driving circuit 300 for each compensation capacitor Ccomp, thereby reducing the complexity and circuit area of ​​the driving circuit. Specifically, the driving circuit includes a touch sensing circuit 200. During the touch sensing period, the touch sensing circuit 200 outputs a touch voltage to drive the sensing electrode. The first terminal of the compensation capacitor Ccomp is connected to the compensation node A of the touch sensing circuit 200, and the second terminal of the compensation capacitor Ccomp is connected to the voltage output terminal of the common electrode driving circuit 100.

[0043] Furthermore, as shown in Figure 3, the first terminal of the compensation capacitor Ccomp is also grounded through the first switch S1. Specifically, during the touch sensing period, the first switch S1 disconnects the ground connection of the compensation capacitor Ccomp, and the common electrode driving circuit 100 outputs a compensation voltage to drive the compensation capacitor Ccomp, so that the compensation capacitor Ccomp provides capacitance compensation to the sensing path. By disconnecting the first switch S1, the grounding of the compensation capacitor Ccomp can be avoided, which would cause the charge to be released through the ground wire, making the compensation capacitor at ground potential (0V) and unable to provide compensation voltage to the touch sensing circuit 200. During the display driving period, since the compensation capacitor Ccomp is in an idle state, in this embodiment, by turning on the ground connection of the compensation capacitor Ccomp through the first switch S1, the compensation capacitor Ccomp can be reused as a storage capacitor to maintain the stability of the common voltage output by the common electrode driving circuit 100, thereby enabling the common electrode driving circuit 100 to provide a more stable voltage hold, thus ensuring the stability and quality of the displayed image.

[0044] Furthermore, as shown in Figure 4, the first end of the compensation capacitor Ccomp can also be connected to the compensation node A of the touch sensing circuit 200 through the second switch S2. During the display driving period, the second switch S2 disconnects the connection between the compensation capacitor Ccomp and the compensation node A of the touch sensing circuit 200. During the touch sensing period, the second switch S2 connects the connection between the compensation capacitor Ccomp and the compensation node A of the touch sensing circuit 200. This avoids the compensation capacitor Ccomp affecting the voltage of the compensation node A, thereby reducing the impact on the preparation state of the touch sensing circuit 200 before sensing. This allows the input and output of the touch sensing circuit 200 to be reset to the corresponding common-mode level before sensing begins, improving touch sensing efficiency.

[0045] In other implementations, as shown in Figure 5, the voltage output terminal of the common electrode driving circuit 100 can also be connected to a storage capacitor Cvcom via a third switch S3. During the display driving period, the third switch S3 connects the common electrode driving circuit 100 and the storage capacitor Cvcom to maintain a stable common voltage; during the touch sensing period, the third switch S3 disconnects the common electrode driving circuit 100 and the storage capacitor Cvcom to avoid the compensation voltage output by the common electrode driving circuit 100 causing additional power consumption during the charging and discharging of the storage capacitor Cvcom. The storage capacitor Cvcom can be located inside or outside the touch display driving chip; this invention does not limit this.

[0046] Based on the above-mentioned method for saving driving circuit area, the present invention also provides an area-saving driving circuit, as shown in FIG2. The driving circuit includes: a multiplexer MUX, used to select the output common voltage to drive the common electrode (in this embodiment, the sensing electrode SX) during the display driving period. <k>During the display driving period, it is reused as a common electrode; during the touch sensing period, the output touch voltage is selected to drive the sensing electrode SX. <k>A compensation capacitor Ccomp is used to compensate for parasitic capacitance on the sensing path. A common electrode driving circuit 100, during the display driving period, is allowed by the multiplexer to output a common voltage to drive the common electrode; during the touch sensing period, the common electrode driving circuit 100 outputs a compensation voltage to drive the compensation capacitor Ccomp. In this embodiment, by multiplexing the common electrode driving circuit 100 as the driving circuit for the compensation capacitor Ccomp during the touch sensing period, the driving circuit no longer needs to set up an additional driving circuit 300 for each compensation capacitor Ccomp, thereby reducing the complexity and circuit area of ​​the driving circuit.

[0047] Specifically, the common electrode driving circuit 100 includes a first sub-driving module 101. The first sub-driving module 100 outputs a common voltage during the display driving period or a compensation voltage during the touch sensing period. The first sub-driving module 101 shown in Figure 2 is an operational amplifier. In other embodiments, the first sub-driving module 101 can also have other structures, as long as it can output a common voltage during the display driving period or a compensation voltage during the touch sensing period. The common voltage is typically a fixed level to drive the common electrode to a voltage stable state. The compensation voltage is a voltage waveform opposite to the sensing signal Vsx. Both the fixed level and the compensation voltage can be achieved by setting the input voltage VCOM_REF of the first sub-driving module 101. The high and low levels of the compensation voltage can be selected according to the compensation current requirements and circuit performance, etc., and this embodiment does not impose any restrictions on this.

[0048] The driving circuit further includes a touch sensing circuit 200, which, during the touch sensing period, is enabled by the multiplexer MUX to output a touch voltage to drive the sensing electrode SX. <k>Furthermore, during the display driving period, the touch sensing circuit 200 is in a non-operating state. Specifically, the touch sensing circuit 200 includes a second sub-driving module 201 and a third sub-driving module 202 connected in a circuit. The second sub-driving module 201 is connected to the sensing electrode SX through the multiplexer MUX. <k>The first sub-driver module 201 is connected to the output terminal of the second sub-driver module 201 and is used to output the sensing waveform and convert the sensed capacitance into a current signal. The second sub-driver module 201 and the third sub-driver module 202 shown in Figure 2 are both operational amplifiers. In other embodiments, the second sub-driver module 201 and the third sub-driver module 202 can also be other structures, as long as they can achieve the corresponding functions.

[0049] Specifically, the input terminal of the third sub-driving module 202 is configured with a compensation node A. The first terminal of the compensation capacitor Ccomp is directly connected to the compensation node A, so that the compensation capacitor Ccomp is connected to the touch sensing circuit 200, thereby providing a compensation voltage to offset the parasitic capacitance on the sensing path. The second terminal of the compensation capacitor Ccomp is connected to the voltage output terminal of the common electrode driving circuit 100, so that the common electrode driving circuit 100 can output a compensation voltage during the touch sensing period to drive the compensation capacitor Ccomp to provide capacitance compensation to the sensing path.

[0050] In another embodiment, as shown in FIG3, the first terminal of the compensation capacitor Ccomp is also connected to ground through the first switch S1. By controlling the opening and closing of the first switch S1, the compensation capacitor Ccomp is used to compensate for parasitic capacitance on the sensing path and as a storage capacitor to maintain the stability of the common voltage. Specifically, during the touch sensing period, the first switch S1 is opened, and the common electrode driving circuit 100 outputs a compensation voltage to drive the compensation capacitor Ccomp to provide capacitance compensation to the sensing path, avoiding the compensation capacitor Ccomp from being grounded and causing the charge to be released through the ground wire, so that the compensation capacitor Ccomp is at ground potential (0V) and cannot provide compensation voltage to the touch sensing circuit 200; during the display driving period, the first switch S1 is closed, so that the compensation capacitor Ccomp is grounded. At this time, the compensation capacitor Ccomp is reused as a storage capacitor to maintain the stability of the common voltage output by the common electrode driving circuit 100, thereby enabling the common electrode driving circuit 100 to provide a more stable voltage, thus ensuring the stability and quality of the displayed image.

[0051] In another embodiment, as shown in FIG4, the first end of the compensation capacitor Ccomp can also be connected to the compensation node A through a second switch S2. The second switch S2 is located between the connection point B of the first switch S1 and the first end of the compensation capacitor Ccomp and the compensation node A. During the touch sensing period, the second switch S2 is turned on. During the display driving period, the second switch S2 is turned off to prevent the compensation capacitor Ccomp from grounding and pulling down the voltage of the compensation node A (i.e., the voltage of the compensation node A is 0V), thereby affecting the touch sensing circuit 200 to enter the preparation state before sensing. This allows the input and output of the touch sensing circuit 200 to be reset to the corresponding common-mode level before sensing begins. After the input and output are reset to the common-mode level, the signal baseline used for sensing signal comparison can be stabilized at the common-mode level. The subsequent signal processing unit can more accurately quantify and process the change between the sensing signal and the signal baseline, reduce the error caused by signal baseline fluctuations, improve the processing accuracy of the sensing signal, and improve the touch sensing efficiency.

[0052] As shown in Figure 5, based on the embodiment shown in Figure 2, the voltage output terminal of the common electrode driving circuit 100 can also be connected to a storage capacitor Cvcom via a third switch S3. During the display driving period, the third switch S3 connects the common electrode driving circuit 100 and the storage capacitor Cvcom to maintain the stability of the common voltage; during the touch sensing period, the third switch S3 disconnects the common electrode driving circuit 100 and the storage capacitor Cvcom to avoid the compensation voltage output by the common electrode driving circuit 100 causing additional power consumption for the charging and discharging of the storage capacitor Cvcom.

[0053] The present invention also discloses an area-saving touch display driver chip, wherein the touch display driver chip includes the area-saving driving circuit described in any of the above embodiments.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0055] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above. Therefore, the scope of protection of the present invention should be defined by the appended claims.

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Claims

1. A method for saving driving circuit area, characterized in that the driving circuit includes a common electrode driving circuit, wherein during the display driving period, the common electrode driving circuit outputs a common voltage for driving the common electrode, and during the touch sensing period, the common electrode driving circuit outputs a compensation voltage for driving a compensation capacitor, wherein the compensation capacitor is used to compensate for parasitic capacitance on the sensing path.

2. The method for saving drive circuit area as claimed in claim 1, characterized in that the drive circuit includes a touch sensing circuit, a first end of the compensation capacitor is connected to the compensation node of the touch sensing circuit, and a second end of the compensation capacitor is connected to the voltage output terminal of the common electrode drive circuit.

3. The method for saving drive circuit area as described in claim 2, characterized in that the first terminal of the compensation capacitor is also grounded through a first switch.

4. The method for saving drive circuit area as described in claim 3, characterized in that, during the touch sensing period, the first switch disconnects the ground connection of the compensation capacitor, and the common electrode drive circuit outputs a compensation voltage to drive the compensation capacitor so that the compensation capacitor provides capacitance compensation to the sensing path; during the display drive period, the first switch connects the ground connection of the compensation capacitor so that the compensation capacitor is reused as a storage capacitor to maintain the stability of the common voltage output by the common electrode drive circuit.

5. The method for saving driving circuit area as described in any one of claims 2 to 4, characterized in that the first end of the compensation capacitor is connected to the compensation node of the touch sensing circuit through a second switch, and during the display driving period, the second switch disconnects the compensation capacitor from the compensation node of the touch sensing circuit to avoid the compensation capacitor affecting the voltage of the compensation node.

6. The method for saving drive circuit area as described in claim 2, characterized in that the voltage output terminal of the common electrode drive circuit is connected to a storage capacitor through a third switch; during the display driving period, the third switch connects the common electrode drive circuit and the storage capacitor to maintain the stability of the common voltage; during the touch sensing period, the third switch disconnects the common electrode drive circuit and the storage capacitor to prevent the compensation voltage output by the common electrode drive circuit from charging and discharging the storage capacitor.

7. A space-saving drive circuit, characterized in that it comprises: A multiplexer is used to select an output common voltage to drive a common electrode during the display driving period and to select an output touch voltage to drive a sensing electrode during the touch sensing period; a compensation capacitor is used to compensate for parasitic capacitance on the sensing path; a common electrode driving circuit is allowed by the multiplexer to output a common voltage to drive the common electrode during the display driving period and outputs a compensation voltage to drive the compensation capacitor during the touch sensing period.

8. The area-saving drive circuit as described in claim 7, characterized in that it further comprises: During the touch sensing period, the touch sensing circuit is enabled by the multiplexer to output a touch voltage to drive the sensing electrodes.

9. The area-saving drive circuit as claimed in claim 8, characterized in that the touch sensing circuit comprises: The second sub-driving module is used to output the sensing waveform and convert the sensed capacitance into a current signal; The third sub-driving module is used to convert the current signal into a voltage signal.

10. The area-saving drive circuit as claimed in claim 9, characterized in that a compensation node is provided at the input terminal of the third sub-drive module, and the first terminal of the compensation capacitor is connected to the touch sensing circuit through the compensation node.

11. The area-saving driving circuit as described in any one of claims 7 to 10, characterized in that the common electrode driving circuit includes a first sub-driving module, the first sub-driving module outputting a common voltage during the display driving period or outputting a compensation voltage during the touch sensing period.

12. The area-saving drive circuit as claimed in claim 11, characterized in that the second terminal of the compensation capacitor is connected to the voltage output terminal of the common electrode drive circuit.

13. The area-saving drive circuit as claimed in claim 10, characterized in that the first terminal of the compensation capacitor is also connected to ground via a first switch.

14. The area-saving drive circuit as claimed in claim 13, characterized in that the first end of the compensation capacitor is directly connected to the compensation node, or is connected to the compensation node through a second switch.

15. The area-saving drive circuit as claimed in claim 12, characterized in that the voltage output terminal of the common electrode drive circuit is connected to a storage capacitor via a third switch.

16. The area-saving drive circuit as claimed in claim 7, characterized in that the sensing electrode is reused as the common electrode.

17. A touch display driver chip, comprising an area-saving driver circuit as described in any one of claims 7 to 16.

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