Touch circuit, touch detection amplification circuit and touch device

Abstract

The present application provides a touch circuit, a touch detection amplification circuit and a touch device, which comprises a charge generation circuit, a charging circuit, a control circuit, a touch detection amplification circuit and a data processing circuit. The charge generation circuit detects a sensing capacitor generated by a user touch. The control circuit controls the charging circuit to charge the charge generation circuit, so as to reduce the influence of self-capacitance in the charge generation circuit on the sensing voltage output by the touch detection amplification circuit. The charging circuit comprises a charging capacitor and a buffer. The touch detection amplification circuit converts the sensing capacitor output by the charge generation circuit into a sensing voltage, so as to identify a touch operation and a touch position. The data processing circuit is used to output a control signal according to the sensing voltage output by the touch detection amplification circuit, so as to adjust the capacitance value of the charging capacitor or the capacitance value of a common-mode capacitor in the touch detection amplification circuit, so that the sensing voltage output by the touch detection amplification circuit is in a common-mode voltage effective signal range.

Description

Technical Field

[0001] This invention relates to a touch circuit, a touch detection amplification circuit, and a touch device. Background Technology

[0002] With the development of smartphones, capacitive touch detection is becoming increasingly widespread. Capacitive touch detection solutions are mainly divided into two directions: self-capacitance sensing and mutual capacitance sensing. Among them, self-capacitance sensing is more widely used. In touch and display integrated detection chips, the touch detection solution simply adopts the self-capacitance solution, while in some detection solutions that mainly use mutual capacitance, self-capacitance auxiliary detection is also required.

[0003] Self-capacitance detection requires measuring the magnitude of charge. The circuit needs to convert the charge signal into a voltage signal, which requires a charge amplifier (CA) circuit. However, in integrated circuit manufacturing, due to uncertainties in each process step, even nominally identical devices will exhibit mismatches. These mismatches alter the effective signal range of the CA conversion, thus affecting its accuracy and limiting its application environment. Current technologies often address this by increasing device size, but this results in wasted area, increased circuit capacitance, reduced circuit speed, and increased power consumption. Summary of the Invention

[0004] In view of this, it is necessary to provide a touch circuit, a touch detection amplifier circuit, and a touch device, which aims to solve the technical problem in the prior art of avoiding the influence of differences in device manufacturing processes on the effective range of the output signal of the touch detection amplifier circuit.

[0005] A touch circuit includes a charge generation circuit, a charging circuit, a control circuit, a touch detection amplification circuit, and a data processing circuit. The charge generation circuit is used to scan according to a certain timing control to detect the sensing capacitance generated by the user's touch and sensing electrodes. The control circuit is used to control the charging circuit to charge the charge generation circuit or to control the charge generation circuit to discharge. The touch detection amplification circuit is electrically connected to the charging circuit and the control circuit. The charging circuit includes a charging capacitor, which is electrically connected to the control circuit and the touch detection amplification circuit through a node. The touch detection amplification circuit is used to convert the sensing capacitance output by the charge generation circuit into a sensing voltage to identify touch operation and touch position. The data processing circuit is electrically connected to the touch detection amplification circuit and the charging circuit. The data processing circuit is used to output a control signal according to the sensing voltage output by the touch detection amplification circuit to adjust the capacitance value of the charging capacitor so that the sensing voltage output by the touch detection amplification circuit is within the effective common-mode voltage signal range.

[0006] A touch detection amplification circuit, electrically connected to a charge generation circuit, the touch detection amplification circuit comprising:

[0007] An amplifier is used to convert the sensing capacitance output by the charge generation circuit into a sensing voltage; the first input terminal of the amplifier is electrically connected to the charge generation circuit.

[0008] The sampling module is used to sample the output voltage of the amplifier and output the sampled voltage;

[0009] A reset switch, one end of which is electrically connected to the first input terminal of the amplifier, and the other end of which is electrically connected to the output terminal of the amplifier;

[0010] The main capacitor is connected in parallel between the first input terminal and the output terminal of the amplifier.

[0011] Multiple auxiliary capacitors are provided. One end of each auxiliary capacitor is electrically connected to the first input terminal of the amplifier via a first switching element, and is electrically connected to the output terminal via a second switching element. When the reset switch is on and there is a difference between the sampled voltage and the target voltage, at least one auxiliary capacitor is time-division multiplexed as a common-mode capacitor to store charge and adjust the voltage at the output terminal of the amplifier when the reset switch is off. When the reset switch is off, the first and second switching elements of the multiple auxiliary capacitors are turned on, connecting the multiple auxiliary capacitors in parallel with the main capacitor as an input capacitor.

[0012] A common-mode parameter adjustment module is electrically connected to the sampling module; when there is a difference between the sampling voltage and the target voltage, the common-mode parameter adjustment module controls at least one of the first switching elements to be turned on, sets at least one of the auxiliary capacitors to be time-division multiplexed as the common-mode capacitor, and outputs a translation control signal.

[0013] The translation drive module is electrically connected to the common-mode parameter adjustment module and electrically connected to each of the auxiliary capacitors through multiple third switching elements. When the reset switch is in the on state, the translation drive module is used to control the third switching element corresponding to the common-mode capacitor to be turned on, and to charge the common-mode capacitor according to the translation control signal.

[0014] A touch device includes a touch circuit; the touch circuit includes a charge generation circuit, a charging circuit, a control circuit, a touch detection amplification circuit, and a data processing circuit; the charge generation circuit is used to scan according to a certain timing control to detect the sensing capacitance generated by the user's touch and sensing electrodes; the control circuit is used to control the charging circuit to charge the charge generation circuit or control the charge generation circuit to discharge; the touch detection amplification circuit is electrically connected to the charging circuit and the control circuit; the charging circuit includes a charging capacitor, which is electrically connected to the control circuit and the touch detection amplification circuit through a node; the touch detection amplification circuit is used to convert the sensing capacitance output by the charge generation circuit into a sensing voltage to identify touch operation and touch position; the data processing circuit is electrically connected to the touch detection amplification circuit and the charging circuit; the data processing circuit is used to output a control signal according to the sensing voltage output by the touch detection amplification circuit to adjust the capacitance value of the charging capacitor so that the sensing voltage output by the touch detection amplification circuit is within the common-mode voltage effective signal range.

[0015] A touch device includes a touch detection amplification circuit electrically connected to a charge generation circuit, the touch detection amplification circuit comprising:

[0016] An amplifier is used to convert the sensing capacitance output by the charge generation circuit into a sensing voltage; the first input terminal of the amplifier is electrically connected to the charge generation circuit.

[0017] The sampling module is used to sample the output voltage of the amplifier and output the sampled voltage;

[0018] A reset switch, one end of which is electrically connected to the first input terminal of the amplifier, and the other end of which is electrically connected to the output terminal of the amplifier;

[0019] The main capacitor is connected in parallel between the first input terminal and the output terminal of the amplifier.

[0020] Multiple auxiliary capacitors are provided. One end of each auxiliary capacitor is electrically connected to the first input terminal of the amplifier via a first switching element, and is electrically connected to the output terminal via a second switching element. When the reset switch is on and there is a difference between the sampled voltage and the target voltage, at least one auxiliary capacitor is time-division multiplexed as a common-mode capacitor to store charge and adjust the voltage at the output terminal of the amplifier when the reset switch is off. When the reset switch is off, the first and second switching elements of the multiple auxiliary capacitors are turned on, connecting the multiple auxiliary capacitors in parallel with the main capacitor as an input capacitor.

[0021] A common-mode parameter adjustment module is electrically connected to the sampling module; when there is a difference between the sampling voltage and the target voltage, the common-mode parameter adjustment module controls at least one of the first switching elements to be turned on, sets at least one of the auxiliary capacitors to be time-division multiplexed as the common-mode capacitor, and outputs a translation control signal.

[0022] The translation drive module is electrically connected to the common-mode parameter adjustment module and electrically connected to each of the auxiliary capacitors through multiple third switching elements. When the reset switch is in the on state, the translation drive module is used to control the third switching element corresponding to the common-mode capacitor to be turned on, and to charge the common-mode capacitor according to the translation control signal.

[0023] The aforementioned touch circuit, touch detection amplification circuit, and touch device, depending on the application environment of the touch circuit, can utilize the data processing circuit to adjust the capacitance value of the charging capacitor in the charging circuit or the capacitance value of the common-mode capacitor in the touch detection amplification circuit based on the sensed voltage. This allows for different methods and precision adjustments to the sensed voltage at the amplifier output, maximizing the utilization of the voltage output range of the touch detection amplification circuit and improving its sensitivity and operating speed. Attached Figure Description

[0024] Figure 1 This is a perspective view of a touch device according to a preferred embodiment of the present invention.

[0025] Figure 2 for Figure 1 A schematic diagram of the touch circuit module according to a preferred embodiment.

[0026] Figure 3 for Figure 2 A schematic diagram of the sensing electrode according to a preferred embodiment.

[0027] Figure 4 for Figure 2 A schematic diagram of the equivalent circuit of the touch circuit described in the first embodiment.

[0028] Figure 5 for Figure 4 The diagram illustrates the trend of the capacitance value of the charging capacitor and the sensing voltage.

[0029] Figure 6 for Figure 4 The equivalent circuit diagram of the charging capacitor described in the figure.

[0030] Figure 7 for Figure 4 The waveform diagrams of the reset switch, the sensing voltage, and the charging capacitor are shown in the figure.

[0031] Figure 8 for Figure 2 A schematic diagram of the equivalent circuit of the touch circuit in the first or third stage of the second embodiment.

[0032] Figure 9 for Figure 8 A schematic diagram of the equivalent circuit of the touch circuit in the second embodiment during the second or fourth stage.

[0033] Figure 10 for Figure 8 The diagram shows the waveforms of the first control switch, the second control switch, the third control switch, the first current source, the second current source, the reset switch, and the sensed voltage.

[0034] Figure 11 for Figure 2 A schematic diagram of the equivalent circuit of the touch circuit described in the third embodiment.

[0035] Figure 12 for Figure 11 The waveform diagram of the reset switch and the first translation control signal is shown in the figure.

[0036] Figure 13 for Figure 11 The waveform diagram of the reset switch and the second translation control signal is shown in the figure.

[0037] Figure 14 for Figure 11 A waveform diagram of the first control switch, the second control switch, the third control switch, the pulse voltage, the reset switch, and the sensing voltage.

[0038] Explanation of main component symbols

[0039] Touch device 100

[0040] Touch circuits 200, 200a, 200b, 200c

[0041] Charge generation circuit 10

[0042] Charging circuits 20, 20a, 20b, 20c

[0043] Control circuit 30

[0044] Touch detection amplifier circuit 40

[0045] Data processing circuit 50

[0046] Sensing electrode 12

[0047] Self-capacitance Csensor

[0048] Human body capacitance Cfinger

[0049] First control switch φ11

[0050] Second control switch φ12

[0051] Third control switch φ22

[0052] Amplifier 41

[0053] Main capacitor Ca

[0054] Reset switch rst

[0055] Charging capacitor Cb

[0056] First switching elements S1-1 to S1-p

[0057] Second switching elements S2-1 to S2-p

[0058] Charged electronic capacitors Cb-1~Cb-p

[0059] Buffer 21

[0060] Node N

[0061] Sensing voltage Vout

[0062] Pulse voltage Vtx

[0063] First current source Ibp

[0064] Second current source Ibn

[0065] Auxiliary capacitors C1-1 to C1-p

[0066] Third switching element S3-1~S3-p

[0067] Sampling module 43

[0068] Common mode parameter adjustment module 45

[0069] Translation drive module 47

[0070] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0071] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0072] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a connection that allows for mutual communication; it can be a direct connection or an indirect connection through an intermediate connection; it can be a connection within two components or an interaction between two components. Those skilled in the art can readily understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0073] The terms "first," "second," and "third," etc., used in the specification and accompanying drawings of this invention are for distinguishing different objects, not for describing a specific order. Furthermore, the term "comprising," and any variations thereof, are intended to cover non-exclusive inclusion.

[0074] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0075] The specific embodiments of the touch circuit, touch detection amplification circuit, and touch device of the present invention will be described below with reference to the accompanying drawings.

[0076] Please refer to Figure 1 This is a perspective view of a touch device 100 according to an embodiment of the present invention. In at least one embodiment of the present invention, the touch device 100 can be a mobile device such as a personal computer, tablet computer, smartphone, personal digital assistant (PDA), game console, interactive network television (Internet Protocol Television, IPTV), smart wearable device, navigation device, etc., or a fixed device such as a desktop computer, server, digital television, etc. The touch device 100 may further include one or more of the following combinations: fingerprint recognition function, display function, and camera function. The touch device 100 includes a touch circuit 200 (e.g., ...). Figure 2(As shown). In at least one embodiment of the present invention, the touch circuit 200 may include at least one integrated circuit board and a plurality of electronic components electrically connected to the integrated circuit board, such as capacitors, resistors, and chips.

[0077] Please refer to the following: Figure 2 This is a schematic diagram of the touch circuit 200 according to a preferred embodiment. The touch circuit 200 includes a charge generation circuit 10, a charging circuit 20, a control circuit 30, a touch detection amplification circuit 40, and a data processing circuit 50. In at least one embodiment of the present invention, the touch device 100 operates in a specified voltage domain. The specified voltage domain is used to define the voltage variation range of the touch device 100, with the power supply voltage VDD as the upper limit voltage and the low-level voltage VSS as the lower limit voltage.

[0078] The charge generation circuit 10 scans according to a certain timing control to detect the user's touch operation and generate the sensing capacitance. For example... Figure 3 As shown, the charge generation circuit 10 includes sensing electrodes 12 arranged in an m*n matrix. Here, m and n are positive integers, and they can be the same or different. A self-capacitance Csensor (e.g., ...) is formed between the sensing electrodes 12 and ground. Figure 4 (As shown). After a user touches the screen with their finger, a human body capacitance Cfinger is formed between the sensing electrode 12 in the touch area and the finger (e.g., ...). Figure 4 As shown in the figure, the self-capacitance Csensor and the human body capacitance Cfinger are connected in parallel to form the sensing capacitor. The sensing electrode 12 is electrically connected to the touch detection amplification circuit 40 through a sensing line (not shown).

[0079] In at least one embodiment of the present invention, the touch device 100 has a capacitive touchscreen. For a capacitive touchscreen, when a human body is not touching the screen, the sensing capacitance corresponding to each sensing electrode 12 is the self-capacitance Csensor, and the self-capacitance Csensor serves as a reference capacitance, that is, the capacitance of the sensing electrode 12 relative to ground is a fixed value. When a human body touches the screen, the sensing capacitance corresponding to each sensing electrode 12 is the self-capacitance Csensor plus the human body capacitance Cfinger. The touch detection amplification circuit 40 can determine the touch position by detecting the change in the capacitance value of the sensing capacitance of each sensing electrode 12 during the touch period. However, when the self-capacitance Csensor is large, the relative change in the sensing capacitance is small. Therefore, the reference capacitance needs to be reduced or eliminated during the touch period to avoid adverse effects on touch detection.

[0080] Please refer to the following: Figure 4This is an equivalent circuit diagram of the touch circuit 200a according to the first embodiment. The charging circuit 20a is electrically connected to the charge generation circuit 10 and the control circuit 30. The charging circuit 20a is used to charge the charge generation circuit 10 under the control of the control circuit 30. The charging circuit 20a is used to adjust the sensing voltage Vout output by the touch detection amplification circuit 40 according to the control signal of the data processing circuit 50, so that the sensing voltage Vout output by the touch detection amplification circuit 40 is within the effective common-mode voltage signal range. That is, the effective swing amplitude of the sensing voltage Vout output by the touch detection amplification circuit 40 is maximized. The effective common-mode voltage signal range is located within the specified voltage domain. Wherein, when the sensing voltage Vout is located at the middle level of the specified voltage domain, it can obtain the maximum swing amplitude within the specified voltage domain. For example, taking the specified voltage domain as the low-level voltage VSS being 0 volts (V) and the power supply voltage VDD being 1.5V as an example, when the sensed voltage Vout is at 1.5V, it has a maximum upward and downward swing amplitude of 1.5V. In at least one embodiment of the present invention, the effective common-mode voltage signal range can be 1.3V-1.7V. In other embodiments, the touch device 100 may also be provided with multiple effective common-mode voltage signal ranges of different ranges, and the sensed voltage Vout of the touch device 100 can be measured by the user selecting one of the effective common-mode voltage signal ranges.

[0081] Please refer to the following: Figure 2 and Figure 4 The charging circuit 20a includes a charging capacitor Cb and a buffer 21. One end of the charging capacitor Cb is electrically connected to the sensing electrode 12 via node N and the control circuit 30, and is also electrically connected to the touch detection amplification circuit 40 via node N. The other end of the charging capacitor Cb is electrically connected to the buffer 21. The buffer 21 receives a pulse voltage Vtx. The charging capacitor Cb performs charging / discharging operations based on the pulse voltage Vtx output by the buffer 21. The capacitance value of the charging capacitor Cb can be adjusted according to the correction signal output by the data processing circuit 50 to ensure that the sensing voltage Vout is within the effective signal range of the common-mode voltage. In at least one embodiment of the present invention, as... Figure 5As shown, the capacitance value of the charging capacitor Cb changes proportionally to the sensing voltage Vout detected by the data processing circuit 50. That is, when it is necessary to increase the sensing voltage Vout, the capacitance value of the charging capacitor Cb increases according to the control signal output by the data processing circuit 50; when it is necessary to decrease the sensing voltage Vout, the capacitance value of the charging capacitor Cb decreases according to the control signal output by the data processing circuit 50.

[0082] Please refer to the following: Figure 4 and Figure 6This is an equivalent circuit diagram of the charging capacitor Cb. The charging capacitor Cb includes multiple sub-capacitors Cb-1 to Cb-p, multiple first switching elements S1-1 to S1-p, and multiple second switching elements S2-1 to S2-p. Here, p is a positive integer greater than 1. One end of each sub-capacitor Cb-1 to Cb-p is electrically connected to the first input terminal of the amplifier 41 through the corresponding first switching element S1-1 to S1-p. The other end of each sub-capacitor Cb-1 to Cb-p is electrically connected to the buffer 21 through the corresponding second switching element S2-1 to S2-p. In the first embodiment of the present invention, the capacitance values ​​of the multiple sub-capacitors Cb-1 to Cb-p are encoded in binary format according to their arrangement order. The capacitance values ​​of each sub-capacitor Cb-1 to Cb-p are different and arranged in a geometric progression. In at least one embodiment of the present invention, when the correction signal is in bits, at least one first switching element S1-k and at least one corresponding second switching element S2-k are controlled to be turned on according to the correction signal, so that at least one corresponding sub-capacitor Cb-k is used as the charging capacitor Cb, thereby adjusting the capacitance value of the charging capacitor Cb using a binary encoding method. Here, k is a positive integer and less than p. For example, when bit is 2, i.e., the corresponding binary code is 010, the first switching element S1-2 and the corresponding second switching element S2-2 are turned on according to the encoding order to select the second sub-capacitor Cb-2 as the common-mode capacitor; when bit is 3, i.e., the corresponding binary code is 011, the first switching elements S1-1 to S1-2 and the corresponding second switching elements S2-1 to S2-2 are turned on according to the encoding order to select the first sub-capacitor Cb-1 and the second sub-capacitor Cb-2 together as the charging capacitor Cb. When bit 4 is active, corresponding to binary code 100, the first switching element S1-3 and the corresponding second switching element S2-3 are turned on according to the encoding order to select the third charging sub-capacitor Cb-3 as the charging capacitor Cb. In other embodiments, the multiple charging sub-capacitors Cb-1 to Cb-p can also be encoded using a one-hot code format, with each charging sub-capacitor Cb-1 to Cb-p being independently controlled. The capacitance values ​​of each charging sub-capacitor Cb-1 to Cb-p are the same. By controlling the number of times at least one first switching element S1-k and at least one corresponding second switching element S2-k are turned on, the number of charging sub-capacitors Cb-1 to Cb-p selected as the charging capacitor Cb is achieved, thereby realizing the capacitance adjustment of the charging capacitor Cb using the one-hot code method.For example, when the first switching element S1-1 to S1-3 and the corresponding second switching element S2-1 to S2-3 are turned on, the three sub-capacitors Cb-1 to Cb-3 together serve as the charging capacitor Cb; when the first switching element S1-1 to S1-4 and the corresponding second switching element S2-1 to S2-4 are turned on, the four sub-capacitors Cb-1 to Cb-4 together serve as the charging capacitor Cb.

[0083] The control circuit 30 is electrically connected to the charge generation circuit 10, the charging circuit 20a, and the touch detection amplification circuit 40. The control circuit 30 controls the charging circuit 20a to perform charging / discharging operations on the charge generation circuit 10 based on the power supply voltage VDD and the ground voltage VSS, thereby reducing the influence of the self-capacitance Csensor on the sensing voltage Vout output by the touch detection amplification circuit 40. The control circuit 30 includes a first control switch φ11, a second control switch φ12, and a third control switch φ22. One end of the first control switch φ11 receives the power supply voltage VDD, and the other end is electrically connected to the sensing electrode 12. One end of the second control switch φ12 is grounded, and the other end is electrically connected to the sensing electrode 12. One end of the third control switch φ22 is electrically connected to the sensing electrode 12, and the other end is electrically connected to the touch detection amplification circuit 40 through node N of the charging circuit 20a.

[0084] The touch detection amplification circuit 40 is electrically connected to the control circuit 30 and the data processing circuit 50. The touch detection amplification circuit 40 converts the capacitance value of the sensing capacitor into a voltage signal, integrates and amplifies it, and then outputs the sensing voltage Vout to the data processing circuit 50. This allows the data processing circuit 50 to process the sensing voltage Vout to determine whether the sensing electrode 12 has been touched and to obtain the corresponding touch position. The touch detection amplification circuit 40 includes an amplifier 41, a main capacitor Ca, and a reset switch rst.

[0085] The amplifier 41 is electrically connected to the control circuit 30. The amplifier 41 converts the capacitance value of the sensing capacitor into a voltage signal, integrates it, and outputs the sensing voltage Vout. The first input terminal of the amplifier 41 is electrically connected to the sensing electrode 12 via the third control switch φ22, the second input terminal of the amplifier 41 receives a reference voltage Vcm, and the output terminal of the amplifier 41 is electrically connected to the data processing circuit 50. In at least one embodiment of the present invention, the reference voltage Vcm is half of the power supply voltage VDD.

[0086] One end of the main capacitor Ca is electrically connected to the first input terminal of the amplifier 41, and the other end is electrically connected to the output terminal of the amplifier 41.

[0087] One end of the reset switch rst is electrically connected to the first input terminal of the amplifier 41, and the other end is electrically connected to the output terminal of the amplifier 41.

[0088] The data processing circuit 50 is electrically connected to the charging circuit 20a and the touch detection amplification circuit 40. The data processing circuit 50 outputs a control signal based on the sensing voltage Vout output by the touch detection amplification circuit 40, thereby adjusting the capacitance value of the charging capacitor Cb in the charging circuit 20a, and thus adjusting the sensing voltage Vout. In at least one embodiment of the present invention, the data processing circuit 50 uses an analog-to-digital converter (ADC) to convert the sensing voltage Vout and obtain the control signal.

[0089] Due to the presence of a bias voltage, the voltage at the first input terminal of the amplifier 41 may shift upward or downward, causing the sensing voltage Vout output by the touch detection amplifier circuit 40 to exceed the effective common-mode voltage signal range. In at least one embodiment of the present invention, the data processing circuit 50 detects the sensing voltage Vout and adjusts the capacitance value of the charging capacitor Cb in the charging circuit 20a according to the detection result, so as to maintain the sensing voltage Vout output by the touch detection amplifier circuit 40 at its maximum swing within the effective common-mode voltage signal range.

[0090] Specifically, the data processing circuit 50 detects the sensing voltage Vout output by the touch detection amplifier circuit 40 and determines whether the difference between the sensing voltage Vout and the preset common-mode voltage is within a predetermined difference range. In at least one embodiment of the present invention, the predetermined difference range may be within the effective signal range of the common-mode voltage. For example, taking the preset common-mode voltage as 1.5V and the effective signal range of the common-mode voltage as 1.3V-1.7V, the predetermined difference range may be -0.2V to 0.2V. If the difference between the sensing voltage Vout and the preset common-mode voltage is within the predetermined difference range, it is determined that the capacitance value of the charging capacitor Cb does not need to be corrected, and the current capacitance value of the charging capacitor Cb is stored. If the difference between the sensing voltage Vout and the preset common-mode voltage is outside the predetermined difference range, it is determined that the capacitance value of the charging capacitor Cb needs to be corrected, and the data processing circuit 50 adjusts the capacitance value of the charging capacitor Cb according to the difference between the sensing voltage Vout and the preset common-mode voltage. In at least one embodiment of the present invention, when the difference is positive, the capacitance value of the charging capacitor Cb is decreased according to the control signal output by the data processing circuit 50; when the difference is negative, the capacitance value of the charging capacitor Cb is increased according to the control signal output by the data processing circuit 50.

[0091] Please see Figure 7 The diagram shows the waveforms of the reset switch rst, the sensing voltage Vout, and the charging capacitor Cb. In each operating cycle, the touch detection amplifier circuit 40 performs detection by the sensing electrode 12. The touch device 100 operates sequentially in a first stage T1, a second stage T2, a third stage T3, and a fourth stage T4 within any given operating cycle. The first stage T1 and the second stage T2 constitute a positive half-cycle, and the third stage T3 and the fourth stage T4 constitute a negative half-cycle. In at least one embodiment of the present invention, during the positive half-cycle, the data processing circuit 50 controls the capacitance value of the charging capacitor Cb to remain constant at a preset capacitance value; during the negative half-cycle, the data processing circuit 50 controls the capacitance value of the charging capacitor Cb to be adjusted according to the sensing voltage Vout. In other embodiments, during both the positive and negative half-cycles, the data processing circuit 50 controls the capacitance value of the charging capacitor Cb to be adjusted according to the sensing voltage Vout. The operating principle of the touch device 100 will be explained below using one operating cycle as an example.

[0092] Please see Figure 4In the first stage T1, the first control switch φ11 and the third control switch φ22 are in the off state, while the second control switch φ12 and the reset switch rst are in the on state, causing the charge on the main capacitor Ca and the self-capacitor Csensor to be released, thereby resetting the touch device 100. Simultaneously, the buffer 21 outputs the ground voltage VSS to the charging capacitor Cb. The data processing circuit 50 sets the capacitance value of the charging capacitor Cb in the charging circuit 20a to the preset capacitance value.

[0093] In the second stage T2, the first control switch φ11, the second control switch φ12, and the reset switch rst are in the off state, while the third control switch φ22 is in the on state, causing the self-capacitor Csensor to be charged. Simultaneously, the buffer 21 outputs the power supply voltage VDD to the charging capacitor Cb, causing Cb to discharge to charge the self-capacitor Csensor when there is no finger touch, or to charge both the self-capacitor Csensor and the human body capacitor Cfinger when there is finger touch, thus reducing the influence of the self-capacitor Csensor on the human body capacitor Cfinger.

[0094] In the third stage T3, the second control switch φ12 and the third control switch φ22 are in the off state, while the first control switch φ11 and the reset switch rst are in the on state. This allows the power supply voltage VDD to charge the self-capacitor Csensor when there is no finger touch, or to charge both the self-capacitor Csensor and the human body capacitor Cfinger when there is finger touch, while the main capacitor Ca discharges. Simultaneously, the buffer 21 maintains the output of the power supply voltage VDD to the charging capacitor Cb.

[0095] In the fourth stage T4, the first control switch φ11, the second control switch φ12, and the reset switch rst are in the off state, while the third control switch φ22 is in the on state. This allows the self-capacitance Csensor to discharge when there is no finger touch, or the self-capacitance Csensor and the human body capacitance Cfinger to discharge when there is finger touch, thereby transferring the charge stored on the self-capacitance Csensor to the main capacitor Ca in the touch detection amplification circuit 40. Simultaneously, the buffer 21 outputs the ground voltage VSS to the charging capacitor Cb again, causing Cb to discharge and compensate for the self-capacitance Csensor, reducing its influence on the human body capacitance Cfinger. Meanwhile, the data processing circuit 50 maintains the capacitance value of the charging capacitor Cb at a preset constant value.

[0096] Please see Figure 8 This is a schematic diagram of the equivalent circuit of the touch circuit 200b in the first or third stage of the second embodiment.

[0097] In the second embodiment, the charging circuit 20b in the touch circuit 200b includes a first current source Ibp and a second current source Ibn. The first current source Ibp provides a first charging current, and the second current source Ibn provides a second charging current.

[0098] The control circuit 30 is electrically connected to the charge generation circuit 10, the charging circuit 20b, and the touch detection amplification circuit 40. The control circuit 30 controls the charging circuit 20b to perform charging / discharging operations on the charge generation circuit 10 based on the power supply voltage VDD and the ground voltage VSS, thereby reducing the influence of the self-capacitance Csensor on the sensing voltage Vout output by the touch detection amplification circuit 40. The control circuit 30 operates sequentially in a first stage T1, a second stage T2, a third stage T3, and a fourth stage T4. Specifically, in the first stage T1, the control circuit 30 establishes an electrical connection between the charge generation circuit 10 and the charging circuit 20b, and the power supply voltage VDD charges the self-capacitance Csensor. In the second stage T2, the control circuit 30 establishes an electrical connection between the charge generation circuit 10 and the charging circuit 20b, and the first current source Ibp charges the self-capacitance Csensor, thereby reducing the influence of the self-capacitance Csensor on the human body capacitance Cfinger. The self-capacitor Csensor discharges, transferring the charge on both the self-capacitor Csensor and the human body capacitor Cfinger to the touch detection amplification circuit 40. In the third stage T3, the control circuit 30 disconnects the electrical connection between the charge generation circuit 10 and the charging circuit 20b, and discharges the self-capacitor Csensor. In the fourth stage T4, the control circuit 30 establishes the electrical connection between the charge generation circuit 10 and the charging circuit 20b, and the second current source Ibn charges the self-capacitor Csensor to reduce its influence on the human body capacitor Cfinger. Simultaneously, the charge stored in the capacitor of the touch detection amplification circuit 40 is transferred to the self-capacitor Csensor. The control circuit 30 includes a first control switch φ11, a second control switch φ12, and a third control switch φ22. One end of the first control switch φ11 receives the power supply voltage VDD, and the other end is electrically connected to the sensing electrode 12. One end of the second control switch φ12 is grounded, and the other end is electrically connected to the sensing electrode 12. One end of the third control switch φ22 is electrically connected to the sensing electrode 12, and the other end is electrically connected to the charging circuit 20b and the touch detection amplification circuit 40.

[0099] The touch detection amplification circuit 40 is electrically connected to the control circuit 30 and the data processing circuit 50. The touch detection amplification circuit 40 converts the capacitance value of the sensing capacitor into a voltage signal, integrates and amplifies it, and outputs the sensing voltage Vout to the data processing circuit 50. This allows the data processing circuit 50 to process the sensing voltage Vout to determine whether the sensing electrode 12 has been touched and to obtain the corresponding touch position. Furthermore, the touch detection amplification circuit 40 can adjust the sensing voltage within a specified voltage domain. This specified voltage domain defines the voltage variation range of the touch device 100, with the power supply voltage VDD as the upper limit and the low-level signal VSS as the lower limit. The high-level signal VDD can also be used as the operating voltage of the touch device 100, and the low-level signal VSS can also be used as the ground voltage.

[0100] Please refer to the following: Figure 8 and Figure 9 The touch detection amplification circuit 40 includes an amplifier 41, a main capacitor Ca, a reset switch rst, multiple auxiliary capacitors C1-1 to C1-p, multiple first switching elements S1-1 to S1-p, multiple second switching elements S2-1 to S2-p, multiple third switching elements S3-1 to S3-p, a sampling module 43, a common-mode parameter adjustment module 45, and a translation drive module 47. Here, p is a positive integer greater than 1. In other embodiments, the sampling module 43, the common-mode parameter adjustment module 45, and the translation drive module 47 may also be integrated into the data processing circuit 50.

[0101] The amplifier 41 is electrically connected to the control circuit 30. The amplifier 41 converts the capacitance value of the sensing capacitor into a voltage signal, integrates it, and outputs the sensing voltage Vout. The first input terminal of the amplifier 41 is electrically connected to the sensing electrode 12 via the third control switch φ22. The second input terminal of the amplifier 41 receives a reference voltage Vcm. The output terminal of the amplifier 41 is electrically connected to the sampling module 43 and the data processing circuit 50. In at least one embodiment of the present invention, the reference voltage Vcm is half of the power supply voltage VDD.

[0102] One end of the main capacitor Ca is electrically connected to the first input terminal of the amplifier 41, and the other end is electrically connected to the output terminal of the amplifier 41.

[0103] One end of the reset switch rst is electrically connected to the first input terminal of the amplifier 41, and the other end is electrically connected to the output terminal of the amplifier 41. Wherein, as... Figure 8As shown, the reset switch rst is in the on state during the first stage T1 and the third stage T3, as... Figure 9 As shown, the reset switch rst is in the off state during the second stage T2 and the fourth stage T4.

[0104] One end of each of the auxiliary capacitors C1-1 to C1-p is electrically connected to the first input terminal of the amplifier 41 via the corresponding first switching element S1-1 to S1-p. The other end of each of the auxiliary capacitors C1-1 to C1-p is electrically connected to the output terminal of the amplifier 41 via the corresponding second switching element S2-1 to S2-p, and electrically connected to the translation drive module 47 via the corresponding third switching element S3-1 to S3-p. When the reset switch rst is in the off state, the auxiliary capacitors C1-1 to C1-p act as input capacitors, which can transfer charge, thereby adjusting the voltage at the output terminal of the amplifier 41 upwards or downwards. At least one of the auxiliary capacitors C1-1 to C1-p can be reused as a common-mode capacitor when the reset switch rst is in the on state, to discharge the stored charge and adjust the sensed voltage Vout. In one embodiment of this implementation, the capacitance values ​​of the plurality of auxiliary capacitors C1-1 to C1-p are encoded in binary format according to their arrangement order. In this configuration, the capacitance values ​​of each of the auxiliary capacitors C1-1 to C1-p are distinct and arranged in a geometric progression. Simultaneously, a bit is set to select at least one of the third switching elements S3-1 to S3-p to be turned on, such that at least one corresponding auxiliary capacitor C1-k serves as the common-mode capacitor, thereby achieving selection of the common-mode capacitor using a binary encoding method. Here, k is a positive integer less than p. For example, when bit is 2 (corresponding binary code 010), the third switching element S3-2 is turned on according to the encoding order to select the second auxiliary capacitor C1-2 as the common-mode capacitor; when bit is 3 (corresponding binary code 011), both the third switching elements S3-1 and S3-2 are turned on according to the encoding order to select both the first auxiliary capacitor C1-1 and the second auxiliary capacitor C1-2 as the common-mode capacitor. When bit 4 is active, corresponding to binary code 100, the third switching element S3-3 is turned on according to the encoding order to select the third auxiliary capacitor C1-3 as the common-mode capacitor. In another embodiment of this implementation, the multiple auxiliary capacitors C1-1 to C1-p can also be encoded using a one-hot code format, with each auxiliary capacitor C1-1 to C1-p being independently controlled. The capacitance values ​​of each auxiliary capacitor C1-1 to C1-p are the same. By controlling the number of times the third switching elements S3-1 to S3-p are turned on, the number of auxiliary capacitors C1-1 to C1-p selected as the common-mode capacitor is achieved using a one-hot code method to select the common-mode capacitor.For example, when the third switching elements S3-1 to S3-3 are turned on, the three auxiliary capacitors C1-1 to C1-3 together serve as the common-mode capacitor; when the third switching elements S3-1 to S3-4 are turned on, the four auxiliary capacitors C1-1 to C1-4 together serve as the common-mode capacitor.

[0105] The sampling module 43 is electrically connected to the output terminal of the amplifier 41. The sampling module 43 is used to sample the sensed voltage Vout and output the sampled voltage to the common-mode parameter adjustment module 45. In at least one embodiment of the present invention, the sampling module 43 uses an analog-to-digital converter (ADC) for sampling.

[0106] The common-mode parameter adjustment module 45 is electrically connected to the sampling module 43 and the translation drive module 47. The common-mode parameter adjustment module 45 is used to set the number of auxiliary capacitors C1-1 to C1-p that are reused as common-mode capacitors based on the sampled voltage and the target voltage. The target voltage is the specified common-mode voltage of the amplifier 41.

[0107] Specifically, the common-mode parameter adjustment module 45 uses the difference between the sampled voltage and the target voltage as a shift amount, calculates the common-mode capacitance value based on the shift amount and the capacitance value of the connected capacitor, and obtains the corresponding bit value by looking up the common-mode capacitance value in a table, thereby adjusting the number of auxiliary capacitors C1-1 to C1-p that are reused as common-mode capacitors. The common-mode capacitance value can be calculated according to the following formula.

[0108] Cp = Vdiff / Vt * Cfb (Formula 1)

[0109] Wherein, Cp is the common-mode capacitance value, Vdiff is the difference between the sampled voltage and the target voltage, Vt is the target voltage, and Cfb is the sum of the capacitance values ​​of the connected capacitors. In at least one embodiment of the present invention, the target voltage is half of the power supply voltage VDD.

[0110] The common-mode parameter adjustment module 45 stores a lookup table. The lookup table records the correspondence between multiple common-mode capacitor values ​​and the values ​​of different bit positions.

[0111] Further, the common-mode parameter adjustment module 45 compares the sampled voltage and the target voltage and outputs a translation control signal based on the comparison result to determine the translation direction. When the sampled voltage is greater than the target voltage, it is identified that the voltage at the output terminal of the amplifier 41 is too high, and the common-mode parameter adjustment module 45 outputs a first translation control signal to adjust the voltage at the output terminal of the amplifier 41 downward. When the sampled voltage is less than the target voltage, it is identified that the voltage at the output terminal of the amplifier 41 is too low, and the common-mode parameter adjustment module 45 outputs a second translation control signal to adjust the voltage at the output terminal of the amplifier 41 upward. In one embodiment of this invention, the first translation control signal is the ground voltage GND; the second translation control signal is the power supply voltage VDD. In a third embodiment of the present invention, as... Figure 12 and Figure 13 As shown, the first translation control signal Vtx1 and the second translation control signal Vtx2 are pulse signals with the same frequency but opposite phase. Specifically, the first translation control signal Vtx1 and the control signal of the reset switch rst are synchronous pulse signals with the same phase; the second translation control signal Vtx2 and the control signal of the reset switch rst are synchronous pulse signals with opposite phases.

[0112] The translation drive module 47 is electrically connected to the common-mode parameter adjustment module 45, and is electrically connected to the auxiliary capacitors C1-1 to C1-p respectively through the third switching elements S3-1 to S3-p. The translation drive module 47 is used to control the first switching elements S1-1 to S1-p and the third switching elements S3-1 to S3-p corresponding to the common-mode capacitor to be turned on when the reset switch rst is turned on and there is a difference between the sampled voltage and the target voltage, and to provide the first translation control signal or the second translation control signal to the common-mode capacitor.

[0113] Please refer to the following: Figure 9 and 10 The waveform diagram is shown for the first control switch φ11, the second control switch φ12, the third control switch φ22, the first current source Ibp, the second current source Ibn, the reset switch rst, and the sensing voltage Vout.

[0114] The specific working principle of the touch detection amplification circuit 40 is as follows:

[0115] In the first stage T1, the first control switch φ11 is turned on, while the second control switch φ12 and the third control switch φ22 are turned off. Simultaneously, the reset switch rst is turned on, and the charge on the main capacitor Ca and the auxiliary capacitors C1-1 to C1-p is released.

[0116] In the second stage T2, the first control switch φ11 and the second control switch φ12 are open, and the third control switch φ22 is closed. Simultaneously, the reset switch rst is open, and the charge on the human body capacitor Cfinger is transferred to the main capacitor Ca and the auxiliary capacitors C1-1 to C1-p. The amplifier 41 converts the charge on the human body capacitor Cfinger into a voltage signal and outputs it through its output terminal. Simultaneously, the sampling module 43 samples the voltage at the output terminal of the amplifier 41 and outputs the sampled voltage to the common-mode parameter adjustment module 45. The common-mode parameter adjustment module 45 calculates the shift capacitor value based on the sampled voltage, the target voltage, and the capacitance value of the connected capacitor. When the shift capacitor value is 0, the common-mode parameter adjustment module 45 does not need to connect the auxiliary capacitor. When the shift capacitor value is not 0, the common-mode parameter adjustment module 45 obtains the value of the corresponding bit by looking up a table, and then sets at least one of the auxiliary capacitors C1-1 to C1-p as the common-mode capacitor. In at least one embodiment of the present invention, the smaller the translation capacitance value, the smaller the common mode parameter adjustment module 45 sets the capacitance value of the common mode capacitor.

[0117] In the third stage T3, the second control switch φ12 is turned on, while the first control switch φ11 and the third control switch φ22 are turned off. Simultaneously, the reset switch rst is turned on, and the translation drive module 47 provides either the first translation control signal or the second translation control signal to the common-mode capacitor, thereby charging the common-mode capacitor.

[0118] In the fourth stage T4, the first control switch φ11 and the second control switch φ12 are open, and the third control switch φ22 is closed. Simultaneously, the reset switch rst is in the open state. At this time, the charge stored on the common-mode capacitor is transferred to the main capacitor Ca to adjust the voltage at the output of the amplifier 41 upwards or downwards.

[0119] The aforementioned touch circuit 200b adjusts the voltage at the output terminal of the amplifier 41 by setting multiple auxiliary capacitors C1-1 to C1-p connected in parallel and using a time-division multiplexing method, thereby maximizing the utilization of the voltage output range of the touch detection amplifier circuit 40 and improving the sensitivity and operating speed of the touch detection amplifier circuit 40.

[0120] Please refer to the following: Figure 11This is an equivalent circuit diagram of the touch circuit 200c according to the third embodiment. The touch circuit 200c is essentially the same as the touch circuit 200b. That is, the description of the touch circuit 200b in the second embodiment is generally applicable to the touch circuit 200c in the third embodiment; the main difference lies in the structure of the charging circuit 20c.

[0121] The charging circuit 20c includes a charging capacitor Cb and a buffer 21. One end of the charging capacitor Cb is electrically connected to the sensing electrode 12 through the control circuit 30, and the other end is electrically connected to the buffer 21. The buffer 21 receives a pulse voltage Vtx.

[0122] Please refer to the following: Figure 14 The waveform diagram is shown for the first control switch φ11, the second control switch φ12, the third control switch φ22, the pulse voltage Vtx, the reset switch rst, and the sensing voltage Vout.

[0123] In the first stage T1, the first control switch φ11 is turned on, while the second control switch φ12 and the third control switch φ22 are turned off. The buffer 21 charges the charging capacitor Cb. Simultaneously, the reset switch rst is turned on, causing the charge on the main capacitor Ca and the auxiliary capacitors C1-1 to C1-p to be released.

[0124] In the second stage T2, the first control switch φ11 and the second control switch φ12 are open, and the third control switch φ22 is closed. The buffer 21 stops charging the charging capacitor Cb. The charging capacitor Cb discharges to reduce the influence of the self-capacitance Csensor on the human body capacitor Cfinger. At the same time, the reset switch rst is in the open state, and the charge on the human body capacitor Cfinger is transferred to the main capacitor Ca and the auxiliary capacitors C1-1 to C1-p. The amplifier 41 converts the charge on the human body capacitor Cfinger into a voltage signal and outputs it through the output terminal. At the same time, the sampling module 43 samples the voltage at the output terminal of the amplifier 41 and outputs the sampled voltage to the common-mode parameter adjustment module 45. The common-mode parameter adjustment module 45 calculates the shift capacitor value based on the sampled voltage, the target voltage, and the capacitance value of the connected capacitor, and obtains the value of the corresponding bit by looking up a table, so that when the shift capacitor value is 0, the auxiliary capacitor does not need to be connected. When the shift capacitance value is not 0, the common-mode parameter adjustment module 45 obtains the value of the corresponding bit by looking up a table, and then sets at least one of the auxiliary capacitors C1-1 to C1-p as the common-mode capacitor. The smaller the shift capacitance value, the smaller the capacitance value of the common-mode capacitor set by the common-mode parameter adjustment module 45.

[0125] In the third stage T3, the second control switch φ12 is turned on, while the first control switch φ11 and the third control switch φ22 are turned off. The buffer 21 stops charging the charging capacitor Cb. The charging capacitor Cb discharges to reduce the influence of the self-capacitance Csensor on the human body capacitance Cfinger. Simultaneously, the reset switch rst is turned on, causing the translation drive module 47 to provide the first translation control signal or the second translation control signal to the common-mode capacitor, thereby charging the common-mode capacitor.

[0126] In the fourth stage T4, the first control switch φ11 and the second control switch φ12 are open, and the third control switch φ22 is closed. The buffer 21 recharges the charging capacitor Cb. Simultaneously, the reset switch rst is in the open state. At this time, the charge stored on the common-mode capacitor is transferred to the main capacitor Ca to adjust the voltage at the output of the amplifier 41 upwards or downwards.

[0127] The aforementioned touch circuit 200c, by setting multiple parallel-connected auxiliary capacitors C1-1 to C1-p and employing time-division multiplexing to adjust the voltage at the output terminal of the amplifier 41, maximizes the utilization of the voltage output range of the touch detection amplifier circuit 40, thereby improving the sensitivity and operating speed of the touch detection amplifier circuit 40. Simultaneously, by using a switched capacitor circuit in the charging circuit 20, the influence of the self-capacitance Csensor of the sensing electrode 12 on the human body capacitance Cfinger is reduced, thus expanding the application range of the touch device 100.

[0128] In other embodiments, the touch circuit 200 may also employ the structure of the charging circuit 20a having the charging sub-capacitors Cb-1 to Cb-p in the first embodiment and the structure of the touch detection amplification circuit 40 in the third embodiment. That is, the touch circuit 200 simultaneously includes the charging circuit 20a having the charging sub-capacitors Cb-1 to Cb-p (e.g., Figure 4 (as shown) and the touch detection amplification circuit 40 in the third embodiment (as shown) Figure 11 The touch circuit 200 described above can adjust the sensing voltage Vout by selecting at least one of the charging circuit 20 or the touch detection amplification circuit 40 based on the voltage value of the sensing voltage Vout.

[0129] Differences in the front-end charging circuit 20 will lead to different application environments for the touch circuit 200. To ensure that the sensing voltage Vout achieves maximum swing within a preset common-mode voltage effective range, the application environment can be determined based on whether the front-end charging circuit 20 of the touch circuit 200 is used to provide charging current (e.g., ...). Figure 8 ), or used to provide the charging capacitor Cb (such as Figure 4 The touch detection amplifier circuit 40 can be configured to either correct the charging capacitor Cb or perform common-mode correction on the feedback capacitor. The main capacitor Ca and the common-mode capacitor C1 constitute the feedback capacitor of the touch detection amplifier circuit 40. Adjusting the value of the common-mode capacitor C1 allows for adjustment of the feedback capacitor value of the touch detection amplifier circuit 40.

[0130] The charging circuit 20 at the front end of the touch circuit 200 is used to provide charging current (e.g.) Figure 14 In other words, the front end of the touch circuit 200 is a current base. At this time, there is no capacitor base in the circuit or the range of the charging capacitor Cb is too small to adjust the sensing voltage Vout. In this case, the feedback capacitor value is adjusted by adjusting the capacitance value of the common mode capacitor C1, thereby realizing the common mode correction of the sensing voltage Vout.

[0131] When the charging circuit 20 at the front end of the touch circuit 200 is used to provide a charging capacitor, that is, when the front end of the touch circuit 200 is a capacitor base, the capacitance value of the charging capacitor Cb has a large range. At this time, the common-mode correction of the sensing voltage Vout is performed by adjusting the capacitance value of the charging capacitor Cb.

[0132] In at least one embodiment of the present invention, the capacitance value of the charging capacitor Cb can be set to be within the first capacitance adjustment range and have a certain difference from the second capacitance adjustment range corresponding to the capacitance value of the common-mode capacitor. This ensures that the adjustment range of the feedback capacitance value of the touch detection amplifier circuit 40 is smaller than the first capacitance adjustment range of the charging capacitor Cb, and that the change in the sensing voltage Vout when the capacitance value of the feedback capacitor changes is smaller than the change in the sensing voltage Vout when the capacitance value of the charging capacitor Cb changes. Therefore, adjusting the capacitance value of the charging capacitor Cb according to the sensing voltage Vout can improve the adjustment accuracy of the sensing voltage Vout.

[0133] The aforementioned touch device 100 utilizes the data processing circuit 50 to adjust the capacitance value of the charging capacitor Cb in the charging circuit 20 according to the sensing voltage Vout, thereby adjusting the sensing voltage Vout at the output terminal of the amplifier 41, maximizing the utilization of the voltage output range of the touch detection amplifier circuit 40, and improving the sensitivity and operating speed of the touch detection amplifier circuit 40.

[0134] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A touch circuit, comprising: The touch circuit includes a charge generation circuit, a charging circuit, a control circuit, a touch detection amplification circuit and a data processing circuit; the charge generation circuit is used for scanning according to a certain timing control to detect a sensing capacitor generated by the sensing electrode after a user touch; the control circuit is used for controlling the charging circuit to charge or discharge the charge generation circuit; the touch detection amplification circuit is electrically connected with the charging circuit and the control circuit; the charging circuit includes a charging capacitor, the charging capacitor is electrically connected with the control circuit and the touch detection amplification circuit through a node; the touch detection amplification circuit is used for converting the sensing capacitor output by the charge generation circuit into a sensing voltage to identify a touch operation and a touch position; the data processing circuit is electrically connected with the touch detection amplification circuit and the charging circuit; the data processing circuit is used for outputting a control signal when a difference between the sensing voltage output by the touch detection amplification circuit and a preset common mode voltage is located outside a predetermined difference range; The charging circuit dynamically adjusts a capacitance value of the charging capacitor according to the control signal and the difference between the sensing voltage and the preset common mode voltage, and the touch detection amplification circuit adjusts the sensing voltage within a common mode voltage effective signal range according to the adjusted charging capacitor value.

2. The touch circuit of claim 1, wherein, The capacitance value of the charging capacitor is proportional to the sensing voltage detected by the data processing circuit; when the difference is positive, the capacitance value of the charging capacitor is reduced according to the control signal output by the data processing circuit; When the difference is negative, the capacitance value of the charging capacitor is increased according to the control signal output by the data processing circuit.

3. The touch circuit of claim 1, wherein, The control circuit includes a first control switch, a second control switch and a third control switch; One end of the first control switch receives a power supply voltage, and the other end is electrically connected with the sensing electrode; one end of the second control switch is grounded, and the other end is electrically connected with the sensing electrode of the charge generation circuit; one end of the third control switch is electrically connected with the sensing electrode, and the other end is electrically connected with the touch detection amplification circuit through the node of the charging circuit.

4. The touch circuit of claim 1, wherein, The touch detection amplification circuit includes: An amplifier is used for converting the sensing capacitor output by the charge generation circuit into a sensing voltage; a first input end of the amplifier is electrically connected with the charge generation circuit, a second input end of the amplifier receives a reference voltage, and an output end of the amplifier is connected with a data processing circuit; A reset switch, one end of the reset switch is electrically connected with the first input end of the amplifier, and the other end is electrically connected with the output end of the amplifier; A main capacitor is connected in parallel between the first input end and the output end of the amplifier.

5. The touch circuit of claim 4, wherein, The touch detection amplification circuit further includes: A sampling module is used for sampling the output voltage of the amplifier and outputting a sampling voltage; A plurality of auxiliary capacitors, one end of each of the auxiliary capacitors being electrically connected with the first input terminal of the amplifier through a first switching element and being electrically connected with the output terminal through a second switching element; wherein, when the reset switch is in the on state and there is a difference between the sampling voltage and the target voltage, at least one of the auxiliary capacitors is time-multiplexed as a common-mode capacitor to store electric charge and adjust the voltage of the output terminal of the amplifier when the reset switch is in the off state; when the reset switch is in the off state, the first switching elements and the second switching elements of a plurality of the auxiliary capacitors are turned on, so that a plurality of the auxiliary capacitors are connected in parallel with the main capacitor as access capacitors; A common-mode parameter adjustment module electrically connected with the sampling module; the common-mode parameter adjustment module controls at least one of the first switching elements to be turned on when there is a difference between the sampling voltage and the target voltage, sets at least one of the auxiliary capacitors to be time-multiplexed as the common-mode capacitor, and outputs a shift control signal; A shift driving module electrically connected with the common-mode parameter adjustment module and electrically connected with each of the auxiliary capacitors through a plurality of third switching elements; when the reset switch is in the on state, the shift driving module controls the third switching element corresponding to the common-mode capacitor to be turned on, and charges the common-mode capacitor according to the shift control signal. 6.The touch circuit of claim 5, wherein, The plurality of auxiliary capacitors are encoded in binary format; the capacitance values of each of the auxiliary capacitors are different from each other and arranged in a geometric progression; at least one of the auxiliary capacitors is selected as the common-mode capacitor by setting a bit position, so as to select the common-mode capacitor in a binary encoding mode.

7. The touch circuit of claim 5, wherein, The common-mode parameter adjustment module stores a lookup table; the lookup table records the corresponding relationship between a plurality of common-mode capacitor values and different bit position values; the common-mode parameter adjustment module calculates a common-mode capacitor value according to the difference between the sampling voltage and the target voltage as a shift amount, according to the shift amount and the capacitance value of the access capacitor, obtains the bit position value corresponding to the common-mode capacitor value by looking up the table, and sets the number of the auxiliary capacitors time-multiplexed as the common-mode capacitor according to the bit position value. 8.The touch circuit of claim 1, wherein, The charging capacitor includes a plurality of charging sub-capacitors, a plurality of first switching elements and a plurality of second switching elements; one end of each of the charging sub-capacitors is electrically connected with the node through one of the first switching elements and receives a pulse voltage through one of the second switching elements; The plurality of charging sub-capacitors are encoded in binary format; the capacitance values of each of the charging sub-capacitors are different from each other and arranged in a geometric progression; At least one of the charging sub-capacitors is selected as the charging capacitor by setting a bit position, so as to adjust the capacitance value of the charging capacitor in a binary encoding mode.

9. The touch circuit of claim 1, wherein, The charging capacitor includes a plurality of charging sub-capacitors, a plurality of first switching elements and a plurality of second switching elements; one end of each of the charging sub-capacitors is electrically connected with the node through one of the first switching elements and receives a pulse voltage through one of the second switching elements; The plurality of charging capacitors are encoded in a hot one code format; and the charging capacitors have the same capacitance value.

10. The touch circuit of claim 1, wherein, In each working cycle, the touch circuit works in a positive half cycle and a negative half cycle in sequence; in the positive half cycle, the data processing circuit controls the capacitance value of the charging capacitor to be maintained at a preset constant capacitance value; In the negative half cycle, the data processing circuit controls the capacitance value of the charging capacitor to be adjusted according to the sensing voltage.

11. The touch circuit of claim 10, wherein, The positive half cycle includes a first stage and a second stage; in the first stage, the control circuit controls the charge generation circuit and the touch detection amplification circuit to reset; In the second stage, the control circuit controls the charging capacitor to discharge to charge the self-capacitance in the charge generation circuit; the negative half cycle includes a third stage and a fourth stage; in the third stage, the control circuit provides a power supply voltage to charge the charge generation circuit, and controls the touch detection amplification circuit to discharge; In the fourth stage, the control circuit controls the charge generation circuit to discharge to transfer the charge stored in the human body capacitance in the charge generation circuit to the touch detection amplification circuit.

12. The touch circuit of claim 11, wherein, The charging circuit further includes a buffer; the buffer provides the received pulse voltage to the charging capacitor; in the second stage and the third stage, the buffer provides the power supply voltage to the charging capacitor; in the first stage and the fourth stage, the buffer provides a ground voltage to the charging capacitor.

13. A touch detection amplification circuit electrically connected with a charge generation circuit, characterized in that, The touch detection amplification circuit includes: an amplifier for converting the sensing capacitance output by the charge generation circuit into a sensing voltage; a first input terminal of the amplifier is electrically connected with the charge generation circuit; a sampling module for sampling the output voltage of the amplifier and outputting a sampling voltage; a reset switch, one end of the reset switch is electrically connected with the first input terminal of the amplifier, and the other end is electrically connected with the output terminal of the amplifier; a main capacitor connected in parallel between the first input terminal and the output terminal of the amplifier; a plurality of auxiliary capacitors, one end of each auxiliary capacitor is electrically connected with the first input terminal of the amplifier through a first switching element, and the other end is electrically connected with the output terminal through a second switching element; wherein, when the reset switch is in a conductive state and there is a difference between the sampling voltage and a target voltage, at least one auxiliary capacitor is time-multiplexed as a common-mode capacitor to store charge and adjust the voltage of the output terminal of the amplifier when the reset switch is in a non-conductive state; when the reset switch is in a non-conductive state, the first switching elements and the second switching elements of the plurality of auxiliary capacitors are conductive, so that the plurality of auxiliary capacitors are connected in parallel with the main capacitor as access capacitors. The common-mode parameter adjustment module is electrically connected with the sampling module; when there is a difference between the sampling voltage and the target voltage, the common-mode parameter adjustment module controls at least one of the first switching elements to be turned on, sets at least one of the auxiliary capacitors to be time-division multiplexed as the common-mode capacitor, and outputs a translation control signal; The translation driving module is electrically connected with the common-mode parameter adjustment module and is electrically connected with each of the auxiliary capacitors through a plurality of third switching elements; when the reset switch is in a turned-on state, the translation driving module is configured to control the third switching element corresponding to the common-mode capacitor to be turned on, and charge the common-mode capacitor according to the translation control signal.

14. The touch detection amplification circuit of claim 13, wherein, The plurality of auxiliary capacitors are encoded in a binary format; the capacitance values of each of the auxiliary capacitors are different from each other and are arranged in a geometric progression; at least one of the auxiliary capacitors is selected as the common-mode capacitor by setting a bit position, so as to select the common-mode capacitor in a binary encoding mode.

15. The touch detection amplification circuit of claim 14, wherein, The common-mode parameter adjustment module stores a lookup table; the lookup table records a corresponding relationship between a plurality of common-mode capacitor values and different bit position values; the common-mode parameter adjustment module calculates a common-mode capacitor value according to a difference between the sampling voltage and the target voltage as a translation amount, according to the translation amount and a capacitance value of the access capacitor, obtains a bit position value corresponding to the common-mode capacitor value by looking up the table, and sets a number of the auxiliary capacitors that are multiplexed as the common-mode capacitor according to the bit position value.

16. The touch detection amplification circuit of claim 15, wherein, The common-mode capacitor value is calculated by a formula: Cp = Vdiff / Vt*Cfb; wherein Cp is the common-mode capacitor value, Vdiff is a difference between the sampling voltage and the target voltage, Vt is the target voltage, and Cfb is a sum of the capacitance values of the access capacitors.

17. The touch detection amplification circuit of claim 13, wherein, The common-mode parameter adjustment module further compares the sampling voltage and the target voltage and outputs a translation control signal according to a comparison result to determine a translation direction; when the sampling voltage is greater than the target voltage, the common-mode parameter adjustment module outputs a first translation control signal to downwardly adjust a voltage at the output end of the amplifier; and when the sampling voltage is less than the target voltage, the common-mode parameter adjustment module outputs a second translation control signal to upwardly adjust the voltage at the output end of the amplifier.

18. The touch detection amplification circuit of claim 17, wherein, The first translation control signal is a ground voltage; and the second translation control signal is a power supply voltage.

19. The touch detection amplification circuit of claim 17, wherein, The first translation control signal and the second translation control signal are pulse signals with the same frequency and opposite phases; the first translation control signal and a control signal of the reset switch are synchronous pulse signals with the same phase; and the second translation control signal and the control signal of the reset switch are synchronous pulse signals with opposite phases.

20. The touch detection amplification circuit of claim 13, wherein, The plurality of auxiliary capacitors are encoded in a hot one code format; the capacitance values of each of the auxiliary capacitors are the same; and a number of the auxiliary capacitors that are selected as the common-mode capacitors is selected by controlling a number of the third switching elements that are turned on.

21. A touch device, comprising: The touch device comprises the touch circuit as claimed in any one of claims 1 to 12.

22. A touch device, comprising: The touch device comprises a charge generating circuit, a charging circuit, a control circuit, a touch detection amplification circuit and a data processing circuit; the charge generating circuit is used for scanning in a certain time sequence to detect a sensing capacitor generated by a user approaching a sensing electrode; the charging circuit is used for providing a charging current; the control circuit is used for controlling the charging circuit to charge the charge generating circuit, so as to reduce the influence of self-capacitance in the charge generating circuit on the sensing voltage output by the touch detection amplification circuit, and the touch device comprises the touch detection amplification circuit as claimed in any one of claims 13 to 20.

23. The touch device of claim 22, wherein, The charging circuit comprises a first current source and a second current source; wherein the first current source provides a first charging current to charge the self-capacitance in the charge generating circuit, and the second current source provides a second charging current to discharge the self-capacitance in the charge generating circuit.

24. The touch device of claim 22, wherein, The charging circuit comprises a charging capacitor and a buffer; the buffer is electrically connected to the control circuit through the charging capacitor; and the buffer is used for providing a pulse voltage.

25. The touch device of claim 22, wherein, The control circuit comprises a first control switch, a second control switch and a third control switch; one end of the first control switch receives a power supply voltage, and the other end is electrically connected to the sensing electrode; one end of the second control switch is grounded, and the other end is electrically connected to the sensing electrode of the charge generating circuit; one end of the third control switch is electrically connected to the sensing electrode, and the other end is electrically connected to the touch detection amplification circuit through a node of the charging circuit.

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