WO2022155878A1 - 检测电路、芯片及相关电子装置 - Google Patents

检测电路、芯片及相关电子装置 Download PDF

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Publication number
WO2022155878A1
WO2022155878A1 PCT/CN2021/073214 CN2021073214W WO2022155878A1 WO 2022155878 A1 WO2022155878 A1 WO 2022155878A1 CN 2021073214 W CN2021073214 W CN 2021073214W WO 2022155878 A1 WO2022155878 A1 WO 2022155878A1
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Prior art keywords
terminal
capacitor
sensing capacitor
sensing
switching circuit
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PCT/CN2021/073214
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English (en)
French (fr)
Inventor
余倩
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深圳市汇顶科技股份有限公司
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Priority to PCT/CN2021/073214 priority Critical patent/WO2022155878A1/zh
Publication of WO2022155878A1 publication Critical patent/WO2022155878A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means

Definitions

  • the present application relates to a detection circuit, and in particular, to a capacitance detection circuit, a chip and related electronic devices.
  • capacitance is often detected to cooperate with detection algorithms to complete human-computer interaction in various capacitance-based application scenarios. For example, the wearing state of the headset is detected according to the capacitance detection result, and then whether to play music; for example, the pressure exerted by the user on the mobile phone is judged according to the capacitance detection result, and then the user's gesture and the operation of controlling the mobile phone are judged.
  • external disturbances and changes in temperature often lead to changes in the sensing capacitance value of the sensing capacitor, resulting in erroneous judgments in applications.
  • a single sensing capacitor is divided into two adjacent sensing capacitors, and the sensing is performed in a differential form to reduce the interference of external common mode noise.
  • mutual capacitance will be generated between adjacent sensing capacitors, and the mutual capacitance will participate in charge transfer during the sensing process, resulting in inaccurate sensing results.
  • the change in mutual capacitance will be opposite to the change in the value of the sensing capacitor, making the capacitance sensing result more difficult to interpret. Therefore, how to reduce the influence of external disturbances such as temperature and mutual capacitance between sensing capacitors to make capacitive sensing more accurate has become one of the problems to be solved in the art.
  • One of the objectives of the present application is to disclose a detection circuit, a chip and a related electronic device to solve the above problems.
  • An embodiment of the present application provides a detection circuit.
  • the detection circuit includes first to fourth input terminals, a differential integration circuit, and first to eighth switching circuits.
  • the first input end is coupled to the first end of the first sensing capacitor.
  • the second input terminal is coupled to the second terminal of the first sensing capacitor, the first sensing capacitor has a first inherent capacitance value, and the sensing capacitance value of the first sensing capacitor is at least It is changed because the human body approaches the first end of the first sensing capacitor.
  • the third input terminal is coupled to the first terminal of the second sensing capacitor.
  • the fourth input terminal is coupled to the second terminal of the second sensing capacitor, the second sensing capacitor has a second inherent capacitance value, and the sensing capacitance value of the second sensing capacitor is at least It is changed because the human body approaches the first end of the second sensing capacitor.
  • the differential integration circuit is used for integrating the voltage of the first internal node and the voltage of the second internal node to generate a detection voltage signal when the detection circuit performs a detection operation.
  • the first switching circuit has a first terminal, a second terminal and a third terminal, wherein the first internal node refers to the first terminal of the first switching circuit, and all of the first switching circuit
  • the second terminal is coupled to the first input terminal of the detection circuit
  • the third terminal of the first switching circuit is coupled to the ground terminal
  • the first switching circuit is used for turning on or off The electrical connection between the first input terminal of the detection circuit and the first internal node, and turning on or off the electrical connection between the first input terminal of the detection circuit and the ground terminal sexual connection.
  • the second switching circuit is coupled to the second input terminal of the detection circuit, the first internal node and the ground terminal, and the second switching circuit is used to turn on or turn off the detection circuit
  • the electrical connection between the second input terminal and the first internal node, and the electrical connection between the second input terminal and the ground terminal of the detection circuit is turned on or off.
  • the third switching circuit is coupled to the first internal node and the operating voltage, and the third switching circuit is used to turn on or off the electrical connection between the first internal node and the operating voltage.
  • the fourth switching circuit is coupled to the first internal node and the ground terminal, and the fourth switching circuit is used to turn on or off the electrical property between the first internal node and the ground terminal connect.
  • the fifth switching circuit has a first end, a second end and a third end, wherein the second internal node refers to the first end of the fifth switching circuit, and all the fifth switching circuit
  • the second terminal is coupled to the third input terminal of the detection circuit
  • the second terminal of the fifth switching circuit is coupled to the ground terminal
  • the fifth switching circuit is used for conducting or turn off the electrical connection between the third input terminal of the detection circuit and the second internal node, and turn on or off the connection between the third input terminal of the detection circuit and the ground terminal electrical connection.
  • the sixth switching circuit is coupled to the fourth input terminal, the second internal node and the ground terminal of the detection circuit, and the sixth switching circuit is used to turn on or turn off the detection circuit
  • the electrical connection between the fourth input terminal and the second internal node, and the electrical connection between the fourth input terminal and the ground terminal of the detection circuit is turned on or off.
  • the seventh switching circuit is coupled to the second internal node and the operating voltage, and the seventh switching circuit is used for turning on or off the electrical property between the second internal node and the operating voltage connect.
  • the eighth switching circuit is coupled to the second internal node and the ground terminal, and the eighth switching circuit is used for turning on or off the electrical property between the second internal node and the ground terminal connect.
  • the first switching circuit, the second switching circuit, the third switching circuit, the fourth switching circuit, the fifth switching circuit, the sixth switching circuit, the seventh switching circuit, and the The eighth switching circuit is used for charging or discharging the first sensing capacitor and the second sensing capacitor in the detection operation to eliminate the first sensing capacitor and the second sensing capacitor.
  • the influence of the first mutual capacitance between the two on the detection voltage signal makes the differential integrator circuit output any information related to the proximity of the human body according to the sensing capacitance values of the first sensing capacitor and the second sensing capacitor. the detection voltage signal.
  • Another embodiment of the present application provides a chip including the detection circuit and the detection voltage signal reading circuit for reading the output of the detection circuit.
  • Another embodiment of the present application provides an electronic device, including the detection circuit.
  • the detection circuit, chip and related electronic device of the present application can reduce the interference of external common mode signals such as temperature and the interference of mutual capacitance between sensing capacitors, so that the accuracy of the capacitance signal detected by the detection circuit can be improved.
  • Figure 1 is a schematic diagram of capacitive in-ear detection.
  • FIG. 2 is another schematic diagram of capacitive in-ear detection.
  • FIG. 3 is a schematic diagram of a detection circuit according to an embodiment of the present application.
  • FIG. 4 is a timing diagram of signals received and output by the detection circuit of FIG. 3 when performing a detection operation.
  • FIG. 5 is a schematic diagram of a detection circuit according to another embodiment of the present application.
  • FIG. 6 is a timing diagram of signals received and output by the detection circuit of FIG. 5 when performing a detection operation.
  • FIG. 7 is a diagram showing the arrangement relationship of each sensing capacitor in FIG. 5 .
  • Figure 1 is a schematic diagram of capacitive in-ear detection.
  • the first end of the self-capacitance C SF on the earphone may be the outer plate ET on the earphone casing
  • the second end of the self-capacitance C SF may be the inner plate IT on the earphone casing. Therefore, when someone wears the earphone, the ear will contact the outer electrode plate ET, and the human body equivalent capacitance C B will be connected in parallel with the self-capacitance C SF through the outer electrode plate ET.
  • the outer plate ET is connected to the reading circuit SC, and the inner plate IT is grounded.
  • the voltage read by the reading circuit SC will be related to the capacitance change caused by the external temperature and the equivalent capacitance C B of the human body in parallel with the self-capacitance C SF when the human body is close. voltage, you can determine whether there is a human body close to the earphone, so as to achieve in-ear detection.
  • FIG. 2 is another schematic diagram of capacitive in-ear detection.
  • the original self-capacitance C SF is split into two small self-capacitance C SF1 and C SF2 .
  • the common mode noise caused by the interference of the charger can be eliminated.
  • a mutual capacitance C m will be generated between the self-capacitance C SF1 and C SF2 , and when the human body is close to or the temperature changes, the mutual capacitance C m and the sensing capacitance values of the self-capacitance C SF1 and C SF2 will affect the reading voltage. The opposite effect is caused.
  • the sensing capacitance values of the self-capacitance C SF1 and C SF2 will become larger, while the mutual capacitance C m will become smaller, so that the reading It is difficult for the voltage read by the circuit SC to directly represent the changes caused by the approach of the human body, which also makes the results of the capacitive in-ear detection less accurate.
  • FIG. 3 is a schematic diagram of a detection circuit 100 according to an embodiment of the present application.
  • the detection circuit 100 can be coupled to the first sensing capacitor C S1 and the second sensing capacitor C S2 , although the first sensing capacitor C S1 and the second sensing capacitor C S2 have fixed However, when there is a human body approaching or the temperature changes, the sensing capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 sensed by the detection circuit 100 will change.
  • the circuit 100 can detect the capacitance change through the first sensing capacitor C S1 and the second sensing capacitor C S2 to output the corresponding detection voltage signal VOUT.
  • the human body equivalent capacitance C B of the human body is connected in parallel with the first sensing capacitor C S1 and the second sensing capacitor C S2 , at this time, the sensing capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 will change, and the value of the detection voltage signal VOUT will also change correspondingly.
  • the human body approaching the first sensing capacitor C S1 and the second sensing capacitor C S2 includes the human body approaching or touching the first sensing capacitor C S1 and the second sensing capacitor C S2 .
  • the detection circuit 100 of the present application can eliminate the influence of the mutual capacitance C m between the first sensing capacitor C S1 and the second sensing capacitor C S2 on the detection voltage signal VOUT, so that the detection voltage signal VOUT can be more accurate
  • the ground is used to determine whether there is a human body approaching the first sensing capacitor C S1 and the second sensing capacitor C S2 , so the capacitive touch detection can be more accurate according to the detection voltage signal VOUT. The details are described below.
  • the detection circuit 100 may be disposed in a casing (not shown in the figure) of the electronic device 10 , that is, the casing may cover the detection circuit 100 .
  • the first sensing capacitor C S1 and the second sensing capacitor C S2 can be, for example but not limited to, self-capacitance formed by electrodes on at least a part of the casing, wherein the electrodes on the casing can be The existing conductive parts on the shell, or electrodes specially set on the shell.
  • the first sensing capacitor C S1 and the second sensing capacitor C S2 have inherent capacitance values, when a human body approaches the first sensing capacitor C S1 and the second sensing capacitor C S2 , the first sensing The sensing capacitance values of the capacitor C S1 and the second sensing capacitor C S2 change accordingly.
  • the first ends of the first sensing capacitor C S1 and the second sensing capacitor C S2 may be located outside at least a part of the casing, and the first sensing capacitor C S1 and the second sensing capacitor C The second end of S2 may be located inside at least a portion of the casing.
  • the first terminals of the first sensing capacitor C S1 and the second sensing capacitor C S2 may be the outer plates of the casing, and the first terminals of the first sensing capacitor C S1 and the second sensing capacitor C S2 The two ends may be inner plates of the casing.
  • the human body equivalent capacitance C B will be coupled with the first end of the first sensing capacitor C S1 and the first end of the second sensing capacitor C S2 , The sensing capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 are changed.
  • the present application does not limit the first sensing capacitor C S1 and the second sensing capacitor C S2 to be the self-capacitance formed by the casing.
  • the first sensing capacitor C S2 may also be self-capacitance formed by other components in the electronic device 10 .
  • the detection circuit 100 may include a first input terminal P1, a second input terminal P2, a third input terminal P3, a fourth input terminal P4, a first switching circuit SW1, a second switching circuit SW2, a third switching circuit SW3, and a fourth switching circuit Circuit SW4 , fifth switching circuit SW5 , sixth switching circuit SW6 , seventh switching circuit SW7 , eighth switching circuit SW8 and differential integration circuit 110 .
  • the first input terminal P1 can be coupled to the first terminal of the first sensing capacitor C S1
  • the second input terminal P2 can be coupled to the second terminal of the first sensing capacitor C S1
  • the third input terminal P3 can be coupled to the first terminal of the second sensing capacitor CS2
  • the fourth input terminal P4 can be coupled to the second terminal of the second sensing capacitor CS2 .
  • the detection circuit 100 senses the sensing capacitance value of the first sensing capacitor C S1 through the first input terminal P1 and the second input terminal P2, and detects the sensing capacitance value of the first sensing capacitor C S1 through the third input terminal P3 and the fourth input terminal P4 is used to sense the sensing capacitance value of the second sensing capacitor CS2 .
  • the first switching circuit SW1 has a first terminal, a second terminal and a third terminal.
  • the first terminal of the first switching circuit SW1 is also named as the first internal node NS1.
  • the second terminal of the first switching circuit SW1 can be coupled to the first input terminal P1 and the third terminal of the first switching circuit SW1 can be coupled to the ground terminal GND.
  • the first switching circuit SW1 can turn on or off the first input terminal
  • the electrical connection between P1 and the first internal node NS1 can turn on or off the electrical connection between the first input terminal P1 and the ground terminal GND.
  • the second switching circuit SW2 can be coupled to the second input terminal P2, the first internal node NS1 and the ground terminal GND, and the second switching circuit SW2 can turn on or off the power between the second input terminal P2 and the first internal node NS1
  • the electrical connection between the second input terminal P2 and the ground terminal GND can be turned on or off.
  • the third switching circuit SW3 can be coupled to the first internal node NS1 and the operating voltage VDD, and the third switching circuit SW3 can turn on or off the electrical connection between the first internal node NS1 and the operating voltage VDD.
  • the operating voltage VDD may be greater than the voltage of the ground terminal GND, such as but not limited to the power supply voltage or reference voltage provided in the system where the detection circuit 100 is located.
  • the fourth switching circuit SW4 can be coupled to the first internal node NS1 and the ground terminal GND, and the fourth switching circuit SW4 can turn on or off the electrical connection between the first internal node NS1 and the ground terminal GND.
  • the fifth switching circuit SW5 has a first terminal, a second terminal and a third terminal.
  • the first terminal of the fifth switching circuit SW5 is also named as the second internal node NS2.
  • the second terminal of the fifth switching circuit SW5 may be coupled to the third input terminal P3, the third terminal of the fifth switching circuit SW5 may be coupled to the ground terminal GND, and the fifth switching circuit SW5 may turn on or off the third input
  • the terminal P3 is electrically connected with the second internal node NS2, and can turn on or off the electrical connection between the third input terminal P3 and the ground terminal GND.
  • the sixth switching circuit SW6 can be coupled to the fourth input terminal P4, the second internal node NS2 and the ground terminal GND, and the sixth switching circuit SW6 can turn on or off the power between the fourth input terminal P4 and the second internal node NS2.
  • the electrical connection between the fourth input terminal P4 and the ground terminal GND can be turned on or off.
  • the seventh switching circuit SW7 can be coupled to the second internal node NS2 and the operating voltage VDD, and the seventh switching circuit SW7 can turn on or off the electrical connection between the second internal node NS2 and the operating voltage VDD.
  • the eighth switch circuit SW8 can be coupled to the second internal node NS2 and the ground terminal GND, and the eighth switch circuit SW8 can turn on or off the electrical connection between the second internal node NS2 and the ground terminal GND.
  • the differential integration circuit 110 has a first input terminal NI1 and a second input terminal NI2.
  • the first input terminal NI1 of the differential integration circuit 110 may be coupled to the first internal node NS1
  • the second input terminal NI2 of the differential integration circuit 110 may be coupled to the second internal node NS2 .
  • the differential integration circuit 110 can integrate the voltages of the first internal node NS1 and the second internal node NS2 to generate the detection voltage signal VOUT.
  • the differential integration circuit 110 may include a differential amplifier 112 , a first capacitor C1 , a second capacitor C2 , a ninth switching circuit SW9 and a tenth switching circuit SW10 .
  • the differential amplifier 112 has a first input terminal, a second input terminal, a first output terminal and a second output terminal.
  • the first input terminal of the differential amplifier 112 may be a positive input terminal
  • the second input terminal of the differential amplifier 112 may be a negative input terminal
  • the first output terminal of the differential amplifier 112 may be a positive output terminal and may output a positive output voltage VPO
  • the second output terminal of the differential amplifier 112 can be a negative output terminal and can output a negative output voltage VNO
  • the first output terminal and the second output terminal of the differential amplifier 112 can jointly output the detection voltage signal VOUT.
  • the first capacitor C1 is coupled between the first input terminal of the differential amplifier 112 and the first output terminal of the differential amplifier 112 .
  • the second capacitor C2 is coupled between the second input terminal of the differential amplifier 112 and the second output terminal of the differential amplifier 112 .
  • the ninth switching circuit SW9 can be coupled between the first input terminal of the differential amplifier 112 and the first input terminal NI1 of the differential integrating circuit 110 , and the ninth switching circuit SW9 can turn on or off the first input terminal of the differential amplifier 112 and the first input terminal NI1 of the differential integrating circuit 110 . Electrical connection between the first input terminals NI1 of the differential integration circuit 110 .
  • the tenth switching circuit SW10 may be coupled between the second input terminal of the differential amplifier 112 and the second input terminal NI2 of the differential integrating circuit 110 , and the tenth switching circuit SW10 may turn on or off the second input terminal of the differential amplifier 112 and the second input terminal NI2 of the differential integrating circuit 110 . Electrical connection between the second input terminals NI2 of the differential integration circuit 110 .
  • the detection circuit 100 can sense the sensing capacitances of the first sensing capacitor C S1 and the second sensing capacitor C S2 in a differential manner value, and output the detection voltage signal VOUT accordingly, so the interference of the common mode noise of the external environment on the detection result of the detection voltage signal can be reduced.
  • the first sensing capacitor C S1 and the second sensing capacitor C S2 can also be in the same charging state, and the first internal The node NS1 and the second internal node NS2 are at the same voltage.
  • the two ends of the mutual capacitance C m between the first sensing capacitor C S1 and the second sensing capacitor C S2 will be at the same potential, so there is no
  • the charge is stored so that the detection voltage signal VOUT will not be affected by the mutual capacitance C m , that is, the detection voltage signal VOUT will not change due to the size of the mutual capacitance C m , so that when the capacitance detection is performed according to the detection voltage signal VOUT more accurate results can be obtained.
  • capacitive detection there are many applications of the capacitive detection, such as: capacitive in-ear detection that is often used in earphones to realize the wearing/dropping detection of earphones and then control whether the earphones perform music playback and other operations, and the use of capacitive touch. Detection to realize gesture recognition such as single click, double click, slide, etc., and then complete the human-computer interaction in various application scenarios.
  • the sensing capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 also change, that is, the phenomenon of temperature drift.
  • the detection circuit 100 A third capacitor C3, a fourth capacitor C4, and eleventh to eighteenth switching circuits (SW11 to SW18) may also be included to cancel the inherent capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 .
  • the influence on the detection voltage signal VOUT and the influence on the detection voltage signal VOUT when the sensing capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 change due to temperature changes are offset.
  • the third capacitor C3 has a first end and a second end.
  • the eleventh switching circuit SW11 can turn on or turn off the electrical connection between the first end of the third capacitor C3 and the ground end GND.
  • the twelfth switching circuit SW12 can turn on or turn off the electrical connection between the first end of the third capacitor C3 and the operating voltage VDD.
  • the thirteenth switching circuit S13 can turn on or off the electrical connection between the second end of the third capacitor C3 and the ground terminal GND, and can turn on or off the connection between the second end of the third capacitor C3 and the operating voltage VDD electrical connection.
  • the fourteenth switching circuit S14 can turn on or turn off the electrical connection between the first end of the third capacitor C3 and the first internal node NS1.
  • the fourth capacitor C4 has a first end and a second end.
  • the fifteenth switching circuit SW15 can turn on or turn off the electrical connection between the first end of the fourth capacitor C4 and the ground end GND.
  • the sixteenth switching circuit SW16 can turn on or turn off the electrical connection between the first end of the fourth capacitor C4 and the operating voltage VDD.
  • the seventeenth switching circuit SW17 can turn on or off the electrical connection between the second end of the fourth capacitor C4 and the ground terminal GND, and can turn on or off the connection between the second end of the fourth capacitor C4 and the operating voltage VDD electrical connection.
  • the eighteenth switching circuit SW18 can turn on or turn off the electrical connection between the first end of the fourth capacitor C4 and the second internal node NS2.
  • the first switching circuit SW1 may include a first switch S1 and a second switch S2.
  • the first switch S1 has a first terminal, a second terminal and a control terminal, the first terminal of the first switch S1 is coupled to the first input terminal P1, and the second terminal of the first switch S1 is the first internal node NS1.
  • the second switch S2 has a first terminal, a second terminal and a control terminal. The first terminal of the second switch S2 is coupled to the first input terminal P1, and the second terminal of the second switch S2 is coupled to the ground terminal GND.
  • the second switching circuit SW2 may include a third switch S3 and a fourth switch S4.
  • the third switch S3 has a first terminal, a second terminal and a control terminal.
  • the first terminal of the third switch S3 is coupled to the second input terminal P2, and the second terminal of the third switch S3 is coupled to the first internal node NS1.
  • the fourth switch S4 has a first terminal, a second terminal and a control terminal, the first terminal of the fourth switch S4 is coupled to the second input terminal P2, and the second terminal of the fourth switch S4 is coupled to the ground terminal GND
  • the fifth switching circuit SW5 includes a fifth switch S5 and a sixth switch S6.
  • the fifth switch S5 has a first terminal, a second terminal and a control terminal.
  • the first terminal of the fifth switch S5 is coupled to the third input terminal P3, and the second terminal of the fifth switch S5 is the second internal node NS2.
  • the sixth switch S6 has a first terminal, a second terminal and a control terminal, the first terminal of the sixth switch S6 is coupled to the third input terminal P3, and the second terminal of the sixth switch S6 is coupled to the ground terminal GND.
  • the sixth switching circuit SW6 includes a seventh switch S7 and an eighth switch S8.
  • the seventh switch S7 has a first terminal, a second terminal and a control terminal.
  • the first terminal of the seventh switch S7 is coupled to the fourth input terminal P4, and the second terminal of the seventh switch S7 is coupled to the second internal node NS2.
  • the eighth switch S8 has a first terminal, a second terminal and a control terminal.
  • the first terminal of the eighth switch S8 is coupled to the fourth input terminal P4, and the second terminal of the eighth switch S8 is coupled to the ground terminal GND.
  • the thirteenth switching circuit SW13 includes a ninth switch S9 and a tenth switch S10.
  • the ninth switch S9 has a first terminal, a second terminal and a control terminal, the first terminal of the ninth switch S9 is coupled to the second terminal of the third capacitor C3, and the second terminal of the ninth switch S9 is coupled to the operating voltage VDD .
  • the tenth switch S10 has a first terminal, a second terminal and a control terminal, the first terminal of the tenth switch S10 is coupled to the second terminal of the third capacitor C3, and the second terminal of the tenth switch S10 is coupled to the ground terminal GND .
  • the seventeenth switching circuit SW17 includes an eleventh switch S11 and a twelfth switch S12.
  • the eleventh switch S11 has a first terminal, a second terminal and a control terminal, the first terminal of the eleventh switch S11 is coupled to the second terminal of the fourth capacitor C4, and the second terminal of the eleventh switch S11 is coupled to Operating voltage VDD.
  • the twelfth switch S12 has a first terminal, a second terminal and a control terminal, the first terminal of the twelfth switch S12 is coupled to the second terminal of the fourth capacitor C4, and the second terminal of the twelfth switch S12 is coupled to Ground terminal GND.
  • the SW12, the fourteenth switching circuit SW14, the fifteenth switching circuit SW15, the sixteenth switching circuit SW16, and the eighteenth switching circuit SW18 can be realized by a single switch.
  • the first switching circuit SW1 to the eighteenth switching circuit SW8 can be used to make the first sensing capacitor C S1 , the third capacitor C3 , the second sensing capacitor C S2 and the fourth capacitor C4 respectively charge, The operation of discharging or redistributing charge to perform the detection operation more efficiently and conveniently.
  • the first switching circuit SW1, the second switching circuit SW2, the fifth switching circuit SW5 and the sixth switching circuit SW6 can be controlled by the first control signal K1 and the second control signal K2, the third switching circuit SW3, the sixth switching circuit SW6 can be controlled by the first control signal K1 and the second control signal K2.
  • the seventh switching circuit SW7, the eleventh switching circuit SW11 and the fifteenth switching circuit SW15 can be controlled according to the third control signal K3.
  • the fourth switching circuit SW4, the eighth switching circuit SW8, the twelfth switching circuit SW12 and the sixteenth switching circuit SW16 can be controlled according to the fourth control signal K4.
  • the thirteenth switching circuit SW13 can be controlled according to the fifth control signal K5 and the sixth control signal K6, and the seventeenth switching circuit SW17 can also be controlled according to the fifth control signal K5 and the sixth control signal K6.
  • the fourteenth switching circuit SW14 and the eighteenth switching circuit SW18 can be controlled according to the seventh control signal K7, and the ninth switching circuit SW9 and the tenth switching circuit SW10 can be controlled according to the eighth control signal K8.
  • FIG. 4 is a timing diagram of signals received by the detection circuit 100 when performing a detection operation.
  • the first switch circuit SW1 turns on the electrical connection between the first input terminal P1 and the first internal node NS1
  • the second switch circuit SW2 turns on the first switch circuit SW2.
  • the electrical connection between the two input terminals P2 and the ground terminal GND, the fifth switching circuit SW5 turns on the electrical connection between the third input terminal P3 and the ground terminal GND, and the sixth switching circuit SW6 turns on the fourth switching circuit SW6 Electrical connection between the input terminal P4 and the second internal node NS2.
  • the first switching circuit SW1 turns on the electrical connection between the first input terminal P1 and the ground terminal GND
  • the second switching circuit SW2 turns on the second input terminal P2 and the first internal
  • the thirteenth switching circuit SW13 When the control signal K5 is at a high level, the thirteenth switching circuit SW13 conducts the electrical connection between the second end of the third capacitor C3 and the operating voltage VDD, and the seventeenth switching circuit SW17 conducts the fourth capacitor Electrical connection between the second terminal of C4 and the operating voltage VDD.
  • the thirteenth switching circuit SW13 When the control signal K6 is at a high level, the thirteenth switching circuit SW13 conducts the electrical connection between the second end of the third capacitor C3 and the ground terminal GND, and the seventeenth switching circuit SW17 conducts the fourth capacitor Electrical connection between the second terminal of C4 and the ground terminal GND.
  • the switching circuits SW3, SW4, SW7, SW8, SW9, SW10, SW11, SW12, SW14, SW15 and SW16 will turn on the corresponding control signals of the control signals K3, K4, K7 and K8 when the corresponding control signals are at high potential. It is electrically connected, and when the corresponding control signals in the control signals K3, K4, K7 and K8 are at a low potential, the corresponding electrical connection is turned off.
  • the detection operation may include a first stage ST1 and a second stage ST2, the first stage ST1 may include a first period TP1, a second period TP2 and a third period TP3, and the second stage ST2 may include a fourth period TP4, the fifth period TP5 and the sixth period TP6.
  • the detection circuit 100 can charge the first sensing capacitor C S1 and the third capacitor C3 to the operating voltage VDD, respectively, and make the first sensing capacitor C S1 and the third capacitor C3 jointly couple to the first sensing capacitor C S1 and the third capacitor C3.
  • An internal node NS1 enables the internal charges of the first sensing capacitor C S1 and the third capacitor C3 to be redistributed.
  • the voltage of the first internal node NS1 will only be close to the human body to the first sensing capacitor C S1 , that is, the voltage of the first sensing capacitor C S1
  • the outer plate is used, it is related to the equivalent capacitance of the human body in parallel with the first end of the first sensing capacitor C S1 and the change of the sensing capacitance value caused by temperature, and is related to the inherent capacitance value of the first sensing capacitor C S1 itself.
  • the detection circuit 100 can charge the second sensing capacitor C S2 and the fourth capacitor C4 to the operating voltage VDD respectively, and make the second sensing capacitor C S2 and the fourth capacitor C4 jointly coupled to the second internal node NS2, so that the internal charges of the second sensing capacitor C S2 and the fourth capacitor C4 can be redistributed. Since in the first stage ST1, the third input terminal P3 is continuously coupled to the ground terminal GND, the first terminal of the second sensing capacitor CS2 , that is, the outer plate of the second sensing capacitor CS2 will be continuously coupled to the ground terminal GND. is grounded.
  • both ends of the human body equivalent capacitance C B coupled to the first end of the second sensing capacitor C S2 will be in a grounded state , without causing a change in the sensing capacitance value of the second sensing capacitor C S2 .
  • the voltage of the second internal node NS2 will only be related to the capacitance change caused by temperature, but not related to the second sensing capacitor C
  • the intrinsic capacitance value of S2 itself has nothing to do with the capacitance value of the fourth capacitor C4, that is to say, the voltage of the second internal node NS2 will not be affected by the intrinsic capacitance value of the second sensing capacitor C S2 itself and the capacitance value of the fourth capacitor C4. change in size.
  • the differential integrator 110 performs integration through the first capacitor C1 and the second capacitor C2 according to the voltages of the first internal node NS1 and the second internal node NS2, respectively, the detection voltage signal VOUT will be opposite to each other.
  • the influence of the first sensing capacitor C S1 and the second sensing capacitor C S2 due to temperature can cancel each other out, so that the detection voltage signal VOUT will only be close to the human body, the first sensing The capacitance sensing value of the capacitor C S1 changes.
  • the detection circuit 100 can discharge the first sensing capacitor C S1 to the ground terminal GND, charge the third capacitor C3 to the operating voltage VDD, and then discharge the first sensing capacitor C S1 and the third capacitor C3 is commonly coupled to the first internal node NS1, so that the internal charges of the first sensing capacitor C S1 and the third capacitor C3 can be redistributed.
  • the first terminal of the first sensing capacitor C S1 that is, the outer plate of the first sensing capacitor C S1 will be In a grounded state, and since the human body is generally in a grounded state, when the human body is close to the first sensing capacitor C S1 , the two ends of the human body equivalent capacitance C B coupled to the first end of the first sensing capacitor C S1 will be in the grounding state without causing the change of the sensing capacitance value of the first sensing capacitance C S1 .
  • the voltage of the first internal node NS1 will only be related to the capacitance value change caused by temperature, but not related to the first sensing capacitor.
  • the intrinsic capacitance value of C S1 itself is irrelevant to the capacitance value of the third capacitor C3.
  • the detection circuit 100 can discharge the second sensing capacitor C S2 to the ground terminal, charge the fourth capacitor C4 to the operating voltage VDD, and then make the second sensing capacitor C S2 and the fourth
  • the capacitor C4 is commonly coupled to the second internal node NS2, so that the internal charges of the second sensing capacitor CS2 and the fourth capacitor C4 can be redistributed.
  • the voltage of the second internal node NS2 will only match the voltage of the second sensing capacitor C S2 when the human body is close to the second sensing capacitor C S2.
  • the equivalent capacitance of the human body connected in parallel with the first end of C S2 is related to the change of the sensing capacitance value due to temperature, but has nothing to do with the inherent capacitance value of the second sensing capacitor C S2 itself and the capacitance value of the fourth capacitor C4.
  • the differential integrator 110 performs integration through the first capacitor C1 and the second capacitor C2 according to the voltages of the first internal node NS1 and the second internal node NS2, respectively, the two will cause the detection voltage signal VOUT to be opposite to each other. changes, so that the changes in the sensing capacitances of the first sensing capacitor C S1 and the second sensing capacitor C S2 due to temperature can cancel each other out, and the detection voltage signal VOUT will only change the sensing capacitance caused by the proximity of the human body. related.
  • the detection circuit 100 can detect the influence caused by the equivalent capacitance of the human body through the first sensing capacitor C S1 , and in the second stage ST2, the detection circuit 100 can detect the influence caused by the equivalent capacitance of the human body through the second sensing capacitor C S2 The influence caused by the equivalent capacitance of the human body is detected.
  • the detection voltage signal VOUT output by the detection circuit 100 will include the voltage detected by the first sensing capacitor C S1 and the second sensing capacitor C S2 .
  • the equivalent capacitance of the human body changes, so the change of the equivalent capacitance of the human body can be completely displayed, thereby improving the accuracy of touch detection.
  • the first internal node NS1 and the second internal node NS2 will be at the same voltage, so both ends of the mutual capacitance C m between the first sensing capacitor C S1 and the second sensing capacitor C S2 will be at the same potential. In this case, the mutual capacitance C m will not be Store charge.
  • the detection voltage signal VOUT output by the detection circuit 100 is hardly affected by the mutual capacitance C m , so that the detection voltage signal VOUT can more accurately represent the first sensing capacitor C S1 and the second sensing capacitor C S1 and the second sensing capacitor when the human body approaches.
  • a relatively accurate result can also be obtained when the touch detection is performed according to the detection voltage signal VOUT to measure the change caused by the sensing capacitance value of the capacitance C S2 .
  • the detection voltage signal VOUT outputted by the detection circuit 100 is provided to a reading circuit, such as an analog-digital converter, for value interpretation, so the detection circuit 100 can According to the voltage specification required by the digital conversion circuit, multiple detection operations are continuously performed to gradually integrate the detection voltage signal VOUT into a predetermined detection range suitable for the operation of the analog-to-digital conversion circuit.
  • the chip may include the detection circuit 100 and the readout circuit.
  • the detection circuit 100 has automatically canceled the capacitance value change caused by the temperature when outputting the detection voltage signal VOUT, there is no need to reserve space for the temperature when the analog-to-digital conversion circuit is used to interpret the value subsequently.
  • the impact on the detection voltage signal VOUT in other words, the entire input range of the analog-to-digital conversion circuit can be effectively used to interpret the changes caused by the equivalent capacitance of the human body, thereby increasing the range of effective judgment values.
  • the purpose of the sensing range is not limited to interpret the changes caused by the equivalent capacitance of the human body.
  • the first switching circuit SW1 can turn on the electrical connection between the first input terminal P1 and the first internal node NS1 , and can turn off the electrical connection between the first input terminal P1 and the ground terminal GND electrical connection.
  • the second switching circuit SW2 can cut off the electrical connection between the second input terminal P2 and the first internal node NS1, and can turn on the electrical connection between the second input terminal P2 and the ground terminal GND.
  • the third switching circuit SW3 can turn on the electrical connection between the first internal node NS1 and the operating voltage VDD, so that the first end of the first sensing capacitor C S1 is charged to the operating voltage VDD.
  • the fourth switching circuit SW4 can cut off the electrical connection between the first internal node NS1 and the ground terminal GND.
  • the fifth switching circuit SW5 can cut off the electrical connection between the third input terminal P3 and the second internal node NS2, and can turn on the electrical connection between the third input terminal P3 and the ground terminal GND.
  • the sixth switching circuit SW6 can turn on the electrical connection between the fourth input terminal P4 and the second internal node NS2, and can turn off the electrical connection between the fourth input terminal P4 and the ground terminal GND.
  • the seventh switching circuit SW7 can turn on the electrical connection between the second internal node NS2 and the operating voltage VDD, so that the second end of the second sensing capacitor CS2 is charged to the operating voltage VDD.
  • the eighth switching circuit SW8 can cut off the electrical connection between the second internal node NS2 and the ground terminal GND.
  • the eleventh switching circuit SW11 can conduct the electrical connection between the first terminal of the third capacitor C3 and the ground terminal GND.
  • the twelfth switching circuit SW12 can cut off the electrical connection between the first end of the third capacitor C3 and the operating voltage VDD.
  • the thirteenth switching circuit SW13 can cut off the electrical connection between the second terminal of the third capacitor C3 and the ground terminal GND, and can turn on the electrical connection between the second terminal of the third capacitor C3 and the operating voltage VDD, The second terminal of the third capacitor C3 is charged to the operating voltage VDD.
  • the fourteenth switching circuit SW14 can turn off the electrical connection between the first end of the third capacitor C3 and the first internal node NS1.
  • the fifteenth switching circuit SW15 can conduct the electrical connection between the first end of the fourth capacitor C4 and the ground end GND.
  • the sixteenth switching circuit SW16 can cut off the electrical connection between the first end of the fourth capacitor C4 and the operating voltage VDD.
  • the seventeenth switching circuit SW17 can cut off the electrical connection between the second terminal of the fourth capacitor C4 and the ground terminal GND, and can turn on the electrical connection between the second terminal of the fourth capacitor C4 and the operating voltage VDD, The second terminal of the fourth capacitor C4 is charged to the operating voltage VDD.
  • the eighteenth switching circuit S18 can turn off the electrical connection between the first end of the fourth capacitor C4 and the second internal node NS2.
  • the ninth switching circuit SW9 can turn off the electrical connection between the first input terminal of the differential amplifier 112 and the first internal node NS1, and the tenth switching circuit SW10 can turn off the first input terminal of the differential amplifier 112. Electrical connection between an input terminal and the second internal node NS2.
  • the third switching circuit SW3 can cut off the electrical connection between the first internal node NS1 and the operating voltage VDD, and the eleventh switching circuit SW11 can cut off the third capacitor C3 The electrical connection between the first end of the GND and the ground end GND.
  • the fourteenth switching circuit SW14 can turn on the electrical connection between the first end of the third capacitor C3 and the first internal node NS1, and the thirteenth switching circuit SW13 can turn on the second end of the third capacitor C3 It is electrically connected to the ground terminal GND, and can cut off the electrical connection between the second end of the third capacitor C3 and the operating voltage VDD.
  • the first end of the first sensing capacitor C S1 and the first end of the third capacitor C3 are both coupled to the first internal node NS1, so the charges in the first sensing capacitor C S1 and the third capacitor C3 will be redistributed, and the voltage VX 1 of the first internal node NS1 can be expressed as equation (1).
  • the first sensing capacitor C S1 matches the third capacitor C3
  • the capacitance value of the third capacitor C3 is one third of the inherent capacitance value C S1 of the first sensing capacitor
  • the first internal The voltage VX 1 of the node NS1 will be independent of the inherent capacitance value of the first sensing capacitor C S1 and the capacitance value of the third capacitor C3 , and equation (1) can be rewritten as equation (2).
  • the voltage VX1 of the first internal node NS1 may be substantially equal to 1/2 times the operating voltage VDD.
  • the seventh switching circuit SW7 can cut off the electrical connection between the second internal node NS2 and the operating voltage VDD, and the fifteenth switching circuit SW15 can cut off the first end of the fourth capacitor C4 and the operating voltage VDD.
  • the eighteenth switching circuit SW18 can turn on the electrical connection between the first end of the fourth capacitor C4 and the second internal node NS2, and the seventeenth switching circuit SW17 can turn on
  • the electrical connection between the second terminal of the fourth capacitor C4 and the ground terminal GND can cut off the electrical connection between the second terminal of the fourth capacitor C4 and the operating voltage VDD.
  • the first end of the second sensing capacitor C S2 and the first end of the fourth capacitor C4 are both coupled to the second internal node NS2, so the charges in the second sensing capacitor C S2 and the fourth capacitor C4 will be Redistribution, and in the case where the second sensing capacitor C S2 matches the fourth capacitor C4, for example, when the capacitance value of the fourth capacitor C4 is one third of the inherent capacitance value of the second sensing capacitor C S2 , the voltage VX 2 of the second internal node NS2 has nothing to do with the inherent capacitance value of the second sensing capacitor C S2 and the capacitance value of the fourth capacitor C4 . At this time, the voltage VX 2 can be expressed by equation (3).
  • the self-capacitance value of the casing may not be known when the detection circuit 100 is fabricated, and the first What are the intrinsic capacitance values of the sensing capacitor C S1 and the second sensing capacitor C S2 .
  • the third capacitor C3 may include a variable capacitor or a capacitor array.
  • the user can use the first sensing capacitor
  • the capacitance value of C S1 and the capacitance value of the variable capacitance or the capacitance array are set by the control signal, so that the third capacitance C3 can be matched with the first sensing capacitance C S1 .
  • the fourth capacitor C4 may include a variable capacitor or a capacitor array, and after the user knows the value of the inherent capacitance of the second sensing capacitor C S2 , the user can use the inherent capacitance of the second sensing capacitor C S2 value, and the capacitance value of the variable capacitor or the capacitor array is set by the control signal, so that the fourth capacitor C4 can be matched with the second sensing capacitor C S2 .
  • the seventh control signal K7 changes from a low level to a high level after the third control signal K3 changes from a high level to a low level
  • the fifth control signal K5 changes from a low level to a high level after the seventh control signal K7
  • the high potential changes to the low potential to ensure that the charges in the first sensing capacitor C S1 , the second sensing capacitor C S2 , the third capacitor C3 and the fourth capacitor C4 will not be processed. Transfer to or from outside on reallocation.
  • the present application is not limited to this.
  • the seventh control signal K7 when the third control signal K3 changes from a high level to a low level, the seventh control signal K7 can simultaneously change from a low level to a high level, and when the seventh control signal K3 changes from a high level to a low level at the same time
  • the fifth control signal K5 when the control signal K7 changes from a low level to a high level, the fifth control signal K5 can also change from a high level to a low level at the same time.
  • the fifth control signal K5 and the sixth control signal K6 may be complementary control signals, so the fifth control signal K5 and the sixth control signal K6 also change potentials synchronously.
  • the ninth switching circuit SW9 can turn on the electrical connection between the first input terminal of the differential amplifier 112 and the first internal node NS1, so as to perform integration through the first capacitor C1
  • the tenth switching circuit SW10 can turn on the electrical connection between the first input terminal of the differential amplifier 112 and the second internal node NS2 to perform integration through the second capacitor C2.
  • the length of time that the eighth control signal K8 is at a high level is related to the integration time required by the first capacitor C1 and the second capacitor C2.
  • the eighth control signal K8 is at a high level
  • the length of time can be set to be greater than or equal to the time length sufficient to allow the first capacitor C1 and the second capacitor C2 to complete the integration and to stabilize the voltage VPO of the first output terminal and the voltage VNO of the second output terminal of the differential amplifier 112 .
  • the effects of the first sensing capacitor C S1 and the third capacitor C3 on the voltage VX 1 of the first internal node NS1 can cancel each other, so the first sensing capacitor C S1 and the third capacitor C3 can cancel each other out.
  • the voltage VX1 of an internal node NS1 will be equal to 1/2 times of VDD, regardless of the inherent capacitance of the first sensing capacitor C S1 and the capacitance of the third capacitor C3 .
  • the effects of the second sensing capacitor C S2 and the fourth capacitor C4 on the voltage VX 2 of the second internal node NS2 can also cancel each other, so the voltage VX 2 of the second internal node NS2 will also be equal to 1/2 times VDD, at this time, the first capacitor C1 and the second capacitor C2 will not have charge transfer.
  • the detection voltage signal VOUT is mainly used to present the change of the sensing capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 when the human body approaches, if the voltage VX 1 of the first internal node NS1 and the voltage VX 2 of the second internal node NS2 has nothing to do with the inherent capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 and the capacitance values of the third capacitor C3 and the fourth capacitor C4, which will cause the subsequent generation of The detection voltage signal VOUT will not change due to the size of the first sensing capacitor C S1 , the second sensing capacitor C S2 , the third capacitor C3 and the fourth capacitor C4 , and can more simply and accurately represent the time when the human body is approaching. Changes caused by the sensing capacitance values of the first sensing capacitor CS1 and the second sensing capacitor CS2 .
  • the capacitance change value ⁇ C T1 caused by the temperature and the equivalent capacitance C B of the human body will cause the first input terminal P1 and the second input terminal P1 to change.
  • the sensing capacitance value sensed between the terminals P2 changes, and the voltage VX 1 of the first internal node NS1 also changes accordingly, causing some charges to move into or out of the first capacitor C1, and the transferred charge amount ⁇ QA1 It can be represented as formula (4).
  • the capacitance change value ⁇ C T2 caused by the temperature will also change the sensing capacitance value between the third input terminal P3 and the fourth input terminal P4.
  • the voltage VX 2 of the second internal node NS2 will also change with
  • the third input terminal P3 will remain coupled to the ground terminal GND.
  • the transferred charge amount ⁇ QA2 of the second capacitor C2 can be expressed as Equation (5).
  • the transferred charge amounts ⁇ QA1 and ⁇ QA2 will cause opposite changes in the output voltage of the differential amplifier 112, that is, Under the condition that the intrinsic capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 are the same, the capacitance change value ⁇ C T1 of the first sensing capacitor C S1 and the third capacitor C3 due to temperature drift will be The capacitance change value ⁇ C T2 caused by the temperature of the second sensing capacitor C S2 and the fourth capacitor C4 cancels each other out, so the voltage output by the differential integrator circuit 110 in the first stage will only be equal to the equivalent capacitance C B of the human body.
  • the effect is related to the capacitance change caused by the temperature. For example, when the first capacitor C1 and the second capacitor C2 have the same capacitance value, the detection voltage signal VOUT output by the detection circuit 100 in the first stage can be as shown in equation
  • the first switching circuit SW1 can cut off the electrical connection between the first input terminal P1 and the first internal node NS1, and can turn on the first input terminal P1 and the ground terminal GND and the second switching circuit SW2 can turn on the electrical connection between the second input terminal P2 and the first internal node NS1, and can cut off the electrical connection between the second input terminal P2 and the ground terminal GND. sexual connection.
  • the third switching circuit SW3 can cut off the electrical connection between the first internal node NS1 and the operating voltage VDD, and the fourth switching circuit SW4 can turn on the electrical connection between the first internal node NS1 and the ground terminal GND,
  • the first sensing capacitor C S1 is discharged to the ground terminal GND.
  • the fifth switching circuit SW5 can turn on the electrical connection between the third input terminal P3 and the second internal node NS2, and can turn off the electrical connection between the third input terminal P3 and the ground terminal GND.
  • the sixth switching circuit SW6 can cut off the electrical connection between the fourth input terminal P4 and the second internal node NS2, and can turn on the electrical connection between the fourth input terminal P4 and the ground terminal GND.
  • the seventh switch circuit SW7 can cut off the electrical connection between the second internal node NS2 and the operating voltage VDD, and the eighth switch circuit SW8 can turn on the electrical connection between the second internal node NS2 and the ground terminal GND, so that the first The two sensing capacitors CS2 are discharged to the ground terminal GND.
  • the eleventh switching circuit SW11 can turn off the electrical connection between the first terminal of the third capacitor C3 and the ground terminal GND, and the twelfth switching circuit SW12 can turn on the connection between the first terminal of the third capacitor C3 and the operating voltage VDD
  • the electrical connection between the third capacitor C3 is charged to the operating voltage VDD.
  • the thirteenth switching circuit SW13 can turn on the electrical connection between the second end of the third capacitor C3 and the ground end GND, and can turn off the electrical connection between the second end of the third capacitor C3 and the operating voltage VDD
  • the fourteenth switching circuit SW14 can turn off the electrical connection between the first end of the third capacitor C3 and the first internal node NS1.
  • the fifteenth switching circuit SW15 can turn off the electrical connection between the first end of the fourth capacitor C4 and the ground terminal GND, and the sixteenth switching circuit SW16 can turn on the electrical connection between the first end of the fourth capacitor C4 and the operating voltage VDD is electrically connected, so that the fourth capacitor C4 is charged to the operating voltage VDD.
  • the seventeenth switching circuit SW17 can turn on the electrical connection between the second terminal of the fourth capacitor C4 and the ground terminal GND, and can turn off the electrical connection between the second terminal of the fourth capacitor C4 and the operating voltage VDD.
  • the eighteenth switching circuit SW18 can turn off the electrical connection between the first end of the fourth capacitor C4 and the second internal node NS2.
  • the ninth switching circuit SW9 can turn off the electrical connection between the first input terminal of the differential amplifier 112 and the first internal node NS1, and the tenth switching circuit SW10 can turn off the first input terminal of the differential amplifier 112. Electrical connection between an input terminal and the second internal node NS2.
  • the fourth switching circuit SW4 can cut off the electrical connection between the first internal node NS1 and the ground terminal GND
  • the eighth switching circuit SW8 can cut off the second internal node NS2 and the electrical connection between the ground terminal GND
  • the twelfth switching circuit SW12 can cut off the electrical connection between the first end of the third capacitor C3 and the operating voltage VDD
  • the sixteenth switching circuit SW16 can cut off the fourth capacitor Electrical connection between the first terminal of C4 and the operating voltage VDD.
  • the fourteenth switching circuit SW14 can turn on the electrical connection between the first end of the third capacitor C3 and the first internal node NS1, so as to redistribute the charges in the first sensing capacitor C S1 and the third capacitor C3, and
  • the eighteenth switching circuit SW18 can turn on the electrical connection between the first end of the fourth capacitor C4 and the second internal node NS2 to redistribute the charges in the second sensing capacitor C S2 and the fourth capacitor C4 .
  • the thirteenth switching circuit SW13 can cut off the electrical connection between the second terminal of the third capacitor C3 and the ground terminal GND, and can turn on the electrical connection between the second terminal of the third capacitor C3 and the operating voltage VDD.
  • the seventeenth switching circuit SW17 can turn off the electrical connection between the second terminal of the fourth capacitor C4 and the ground terminal, and can turn on the electrical connection between the second terminal of the fourth capacitor C4 and the operating voltage VDD.
  • the voltage of the first terminal of the third capacitor C3 will also be raised to twice the operating voltage 2VDD.
  • the seventh control signal K7 changes from the low level to the high level after the fourth control signal K4 changes from the high level to the low level, so as to ensure that the first sensing capacitor C S1 , the The charges in the two sensing capacitors C S2 , the third capacitor C3 and the fourth capacitor C4 will not be transferred to or from the outside during redistribution.
  • the seventh control signal K7 can also change from a low level to a high level at the same time.
  • the fifth control signal K5 may change from a low level to a high level after the seventh control signal K7 changes from a low level to a high level, so as to ensure that during the process of redistributing the charges, the second end of the third capacitor C3 and the The potential of the second end of the fourth capacitor C4 can be further raised.
  • the ninth switching circuit SW9 can turn on the electrical connection between the first input terminal of the differential amplifier 112 and the first internal node NS1, so as to perform integration through the first capacitor C1
  • the tenth switching circuit SW10 can turn on the electrical connection between the second input terminal of the differential amplifier 112 and the second internal node NS2 to perform integration through the second capacitor C2.
  • the first output terminal of the differential amplifier 112 And the second output terminal can also output the detection voltage signal VOUT.
  • the capacitance change value ⁇ C T1 of the first sensing capacitor C S1 and the third capacitor C3 due to the temperature will still make the sensing capacitor between the first input terminal P1 and the second input terminal P2
  • the voltage VX 1 of the first internal node NS1 will also change accordingly, causing some charges to move into or out of the first capacitor C1 .
  • the first input terminal P1 is continuously coupled to the ground terminal GND, so even when a human body approaches the first sensing capacitor C S1 , it is coupled to the first sensing capacitor C Both ends of the human body equivalent capacitance CB at the first end of S1 will be in a grounded state without affecting the sensing capacitance value.
  • the transferred charge amount ⁇ QB1 can be expressed as equation (10).
  • the eighth switching circuit SW8 will cut off the electrical connection between the third input terminal P3 and the ground terminal GND. Therefore, when a human body approaches the second sensing capacitor C S2 , the human body will The equivalent capacitance C B of the second sensing capacitor C S2 will be connected in parallel with the second sensing capacitor C S2 through the first end of the second sensing capacitor C S2 , and the sensing capacitance value between the third input end P3 and the fourth input end P4 cause an impact.
  • the capacitance change value ⁇ C T2 of the second sensing capacitor C S2 and the fourth capacitor C4 due to the temperature will also make the sensing capacitor between the third input terminal P3 and the fourth input terminal P4
  • the value changes, so that the voltage VX 2 of the second internal node NS2 changes accordingly, causing part of the charge to move into or out of the second capacitor C2, where the amount of transferred charge ⁇ QB2 can be expressed as equation (11).
  • the detection circuit 100 detects the influence of the human body equivalent capacitance C B on the capacitance value between the first input end P1 and the second input end P2 through the first sensing capacitance C S1
  • the detection circuit 100 detects the influence of the human body equivalent capacitance C B on the capacitance value between the third input terminal P3 and the fourth input terminal P4 through the second sensing capacitor C S2 , Therefore, after the first stage ST1 and the second stage ST2 of the detection operation are completed, the detection voltage signal VOUT can include the human body equivalent capacitance C B detected by the first sensing capacitor C S1 and the second sensing capacitor C S2 changes, so as to fully present the influence of the equivalent capacitance C B of the human body, and ensure the accuracy of touch detection.
  • mutual capacitance C m may occur between the first sensing capacitor C S1 and the second sensing capacitor C S2 , in the first stage ST1 of the detection operation, the first internal node NS1 and the second internal node NS2 will also be charged to the operating voltage VDD, and in the second stage ST2, the first internal node NS1 and the second internal node NS2 will also be discharged to the ground terminal GND. Therefore, during the detection operation, the mutual capacitance C Both ends of m will remain at nearly the same voltage without storing charge. In this way, the influence of the mutual capacitance C m on the detection voltage signal VOUT can be reduced, and a more accurate result can be obtained when the touch detection is performed according to the detection voltage signal VOUT.
  • the differential integration circuit 110 may further include a first reset switch RSW1 and a second reset switch RSW2.
  • the first reset switch RSW1 may be coupled to the first input terminal of the differential amplifier 112 and the first output terminal of the differential amplifier 112 , and the first reset switch RSW1 may turn on the first terminal of the differential amplifier 112 during the reset operation.
  • the electrical connection between an input terminal and the first output terminal of the differential amplifier 112 is used to discharge and reset the first capacitor C1.
  • the second reset switch RSW2 may be coupled to the second input terminal of the differential amplifier 112 and the second output terminal of the differential amplifier 112 , and the second reset switch RSW2 may turn on the first terminal of the differential amplifier 112 during the reset operation.
  • the electrical connection between the two input terminals and the second output terminal of the differential amplifier 112 is used to discharge and reset the second capacitor C2.
  • the first reset switch RSW1 can turn off the electrical connection between the first input terminal of the differential amplifier 112 and the first output terminal of the differential amplifier 112, and the second reset switch RSW2 can be turned off The electrical connection between the second input terminal of the differential amplifier 112 and the second output terminal of the differential amplifier 112 enables the differential integrating circuit 110 to perform integration through the first capacitor C1 and the second capacitor C2.
  • the differential integration circuit 110 Since the first reset switch RSW1 and the second reset switch RSW2 can discharge and reset the first capacitor C1 and the second capacitor C2, the differential integration circuit 110 will not be affected by the previous detection operation during integration. Therefore, the accuracy and stability of the detection circuit 100 can be improved.
  • the detection circuit 100 uses the third capacitor C3 and the fourth capacitor C4 to remove the detection voltage signal VOUT caused by the inherent capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 , and remove the error caused by the change of the sensing capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 due to temperature.
  • the third capacitor C3 and the fourth capacitor C4 can also be replaced by external sensing capacitors, so as to save the area required for the detection circuit.
  • FIG. 5 is a schematic diagram of a detection circuit 200 according to another embodiment of the present application.
  • the detection circuit 200 and the detection circuit 100 have similar structures and can operate according to similar principles.
  • the detection circuit 200 may further include a fifth input terminal P5, a sixth input terminal P6, a seventh input terminal P7, an eighth input terminal P8, a nineteenth switching circuit SW19, a twentieth switching circuit SW20, a twenty-first switching circuit Switching circuit SW21, twenty-second switching circuit SW22, twenty-third switching circuit SW23, twenty-fourth switching circuit SW24, twenty-fifth switching circuit SW25, twenty-sixth switching circuit SW26, twenty-seventh switching circuit SW27 and twenty-eighth switching circuit SW28.
  • the fifth input terminal P5 can be coupled to the first terminal of the third sensing capacitor CS3
  • the sixth input terminal P6 can be coupled to the second terminal of the third sensing capacitor CS3
  • the seventh input terminal The terminal P7 can be coupled to the first terminal of the fourth sensing capacitor CS4
  • the eighth input terminal P8 can be coupled to the second terminal of the fourth sensing capacitor CS4 .
  • the sensing capacitance values of the first sensing capacitor C S1 , the second sensing capacitor C S2 , the third sensing capacitor C S3 and the fourth sensing capacitor C S4 sensed by the detection circuit 200 will vary.
  • the detection circuit 200 can detect capacitance changes through the first sensing capacitor C S1 , the second sensing capacitor C S2 , the third sensing capacitor C S3 and the fourth sensing capacitor C S4 to output a corresponding detection voltage signal VOUT.
  • the third sensing capacitor C S3 and the fourth sensing capacitor C S4 are similar to the first sensing capacitor C S1 and the second sensing capacitor C S2 , and may be the electronic device 20 covering the detection circuit 200 .
  • the first end of the third sensing capacitor C S3 and the first end of the fourth sensing capacitor C S4 may be located outside at least a part of the casing
  • the second end of the third sensing capacitor C S3 and The second end of the fourth sensing capacitor C S4 may be located inside at least a part of the casing.
  • the equivalent capacitance C B of the human body will be related to the first end of the first sensing capacitor C S1 , the first end of the second sensing capacitor C S2 , and the third sensing capacitor.
  • the first terminal of CS3 and the first terminal of the fourth sensing capacitor CS4 are coupled to each other, so that the first sensing capacitor CS1 , the second sensing capacitor CS2 , the third sensing capacitor CS3 and the fourth sensing capacitor.
  • the sensing capacitance value of the sensing capacitor C S4 changes.
  • FIG. 7 is a diagram showing the relationship between the arrangement of the first sensing capacitor C S1 , the second sensing capacitor C S2 , the third sensing capacitor C S3 and the fourth sensing capacitor C S4 in an embodiment of the present application.
  • the first sensing capacitor CS1 and the second sensing capacitor CS2 are arranged adjacently
  • the second sensing capacitor CS2 and the third sensing capacitor CS3 are adjacently arranged
  • the capacitor C S3 and the fourth sensing capacitor C S4 are disposed adjacent to each other, so a mutual capacitance C m1 will be generated between the first sensing capacitor C S1 and the second sensing capacitor C S2
  • the second sensing capacitor C S2 and the Mutual capacitance C m2 is generated between the three sensing capacitors C S3
  • mutual capacitance C m3 is generated between the third sensing capacitor C S3 and the fourth sensing capacitor C S4 .
  • the detection circuit 200 can use the self-capacitance of the external casing as the third sensing capacitor C S3 and the fourth sensing capacitor C S4 to cancel the pair of inherent capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 Detect the influence caused by the voltage signal VOUT, cancel the change caused by the temperature on the sensing capacitance values of the first sensing capacitor C S1 and the second sensing capacitor C S2 , and can eliminate the first mutual capacitance C m1 , the second mutual capacitance C m1 , and the second mutual capacitance C m1 The influence of the capacitance C m2 and the third mutual capacitance C m3 on the detection voltage signal VOUT can therefore replace the third capacitance C3 and the fourth capacitance C4 in the detection circuit 100 , thereby reducing the circuit area required by the detection circuit 200 .
  • the nineteenth switching circuit SW19 can be coupled to the first internal node NS1 and the first input terminal NI1 of the differential integrating circuit 210 , and the nineteenth switching circuit SW19 can turn on or off the first internal node NS1 and the differential integration circuit 210 . Electrical connection between the first input terminals NI1 of the integrating circuit 210 .
  • the twentieth switching circuit SW20 can be coupled to the second internal node NS2 and the second input terminal NI2 of the differential integrating circuit 210 , and the twentieth switching circuit SW20 can turn on or off the second internal node NS2 and the second input terminal NI2 of the differential integrating circuit 210 . Electrical connection between the two input terminals NI2.
  • the differential integration circuit 210 can be coupled to the first internal node NS1 and the second internal node NS2 through the nineteenth switching circuit SW19 and the twentieth switching circuit SW20, and according to the The voltages of the first internal node NS1 and the second internal node NS2 are integrated to generate the detection voltage signal VOUT.
  • the twenty-first switching circuit SW21 can turn on or turn off the electrical connection between the first input terminal NI1 of the differential integration circuit 210 and the ground terminal GND.
  • the twenty-second switching circuit SW22 can turn on or turn off the electrical connection between the first input terminal NI1 of the differential integration circuit 210 and the operating voltage VDD.
  • the twenty-third switching circuit SW23 can turn on or off the electrical connection between the fifth input terminal P5 and the ground terminal GND, and can turn on or off the fifth input terminal P5 and the first input terminal NI1 of the differential integrating circuit 210 electrical connection between them.
  • the twenty-fourth switching circuit SW24 can turn on or off the electrical connection between the sixth input terminal P6 and the ground terminal GND, and can turn on or off the sixth input terminal P6 and the first input terminal NI1 of the differential integrating circuit 210 electrical connection between them.
  • the twenty-fifth switching circuit SW25 can turn on or turn off the electrical connection between the second input terminal NI2 of the differential integration circuit 210 and the operating voltage VDD.
  • the twenty-sixth switching circuit SW26 can turn on or turn off the electrical connection between the second input terminal NI2 of the differential integration circuit 210 and the ground terminal GND.
  • the twenty-seventh switching circuit SW27 can turn on or off the electrical connection between the seventh input terminal P7 and the ground terminal GND, and can turn on or off the seventh input terminal P7 and the second input terminal NI2 of the differential integrating circuit 210 electrical connection between them.
  • the twenty-eighth switching circuit SW28 can turn on or off the electrical connection between the eighth input terminal P8 and the ground terminal GND, and can turn on or off the eighth input terminal P8 and the second input terminal NI2 of the differential integrating circuit 210 electrical connection between them.
  • the twenty-third switching circuit SW23 includes a thirteenth switch S13 and a fourteenth switch S14.
  • the thirteenth switch S13 has a first terminal, a second terminal and a control terminal, the first terminal of the thirteenth switch S13 is coupled to the fifth input terminal P5, and the second terminal of the thirteenth switch S13 is coupled to the differential integrating circuit The first input terminal NI1 of 210.
  • the fourteenth switch S14 has a first terminal, a second terminal and a control terminal, the first terminal of the fourteenth switch S14 is coupled to the fifth input terminal P5, and the second terminal of the fourteenth switch S14 is coupled to the ground terminal GND .
  • the twenty-fourth switching circuit SW24 includes a fifteenth switch S15 and a sixteenth switch S16.
  • the fifteenth switch S15 has a first terminal, a second terminal and a control terminal.
  • the first terminal of the fifteenth switch S15 is coupled to the Six input terminals P6, the second terminal of the fifteenth switch S15 is coupled to the first input terminal NI1 of the differential integration circuit 210.
  • the sixteenth switch S16 has a first terminal, a second terminal and a control terminal, the first terminal of the sixteenth switch S16 is coupled to the sixth input terminal P6, and the second terminal of the sixteenth switch S16 is coupled to the ground terminal GND .
  • the twenty-seventh switching circuit SW27 includes a seventeenth switch S17 and an eighteenth switch S18.
  • the seventeenth switch S17 has a first terminal, a second terminal and a control terminal, the first terminal of the seventeenth switch S17 is coupled to the seventh input terminal P7, and the second terminal of the seventeenth switch S17 is coupled to the differential integrating circuit The second input terminal NI2 of 210.
  • the eighteenth switch S18 has a first terminal, a second terminal and a control terminal, the first terminal of the eighteenth switch S18 is coupled to the seventh input terminal P7, and the second terminal of the eighteenth switch S18 is coupled to the ground terminal GND .
  • the twenty-eighth switching circuit SW28 includes a nineteenth switch S19 and a second time switch S20.
  • the nineteenth switch S19 has a first terminal, a second terminal and a control terminal.
  • the first terminal of the nineteenth switch S19 is coupled to the first terminal.
  • Eight input terminals P8, the second terminal of the nineteenth switch S19 is coupled to the second input terminal NI2 of the differential integration circuit 210.
  • the twentieth switch S20 has a first terminal, a second terminal and a control terminal, the first terminal of the twentieth switch S20 is coupled to the eighth input terminal P8, and the second terminal of the twentieth switch S20 is coupled to the ground terminal GND .
  • the twenty-first switching circuit SW21, the twenty-second switching circuit SW22, the twenty-fifth switching circuit SW25, and the twenty-sixth switching circuit SW26 may be implemented by a single switch.
  • the circuit SW27 and the twenty-eighth switch circuit SW28 can turn on or off the corresponding electrical connection according to the first control signal K1 and the second control signal K2, the third switch circuit SW3, the seventh switch circuit SW7, the twenty-first The switching circuit SW21 and the twenty-fifth switching circuit SW25 can turn on or turn off the corresponding electrical connections according to the third control signal K3.
  • the fourth switching circuit SW4, the eighth switching circuit SW8, the twenty-second switching circuit SW22, and the twenty-sixth switching circuit SW26 can turn on or turn off the corresponding electrical connections according to the fourth control signal K4.
  • the nineteenth switching circuit SW19 and the twentieth switching circuit SW20 can turn on or off the corresponding electrical connections according to the ninth control signal K9, and the ninth switching circuit SW9 and the tenth switching circuit SW10 can turn on or off the corresponding electrical connections according to the eighth control signal K8 to turn on or off the corresponding electrical connection.
  • FIG. 6 is a timing diagram of signals received by the detection circuit 200 when performing a detection operation.
  • the first switching circuit SW1 when the control signal K1 is at a high level, the first switching circuit SW1 will conduct the electrical connection between the first input terminal P1 and the first internal node NS1, and the second switching circuit SW2 will conduct the first switching circuit SW2.
  • the twenty-third switching circuit SW23 conducts the electrical connection between the fifth input terminal P5 and the ground terminal GND
  • the twenty-fourth switching circuit SW24 conducts the electrical connection between the fifth input terminal P5 and the ground terminal GND.
  • the twenty-seventh switching circuit SW27 will conduct the electrical connection between the seventh input terminal P7 and the ground terminal GND
  • the twenty-eighth switching circuit SW28 turns on the electrical connection between the eighth input terminal P8 and the second input terminal NI2 of the differential integrating circuit 210 .
  • the first switching circuit SW1 When the control signal K2 is at a high level, the first switching circuit SW1 turns on the electrical connection between the first input terminal P1 and the ground terminal GND, and the second switching circuit SW2 turns on the second input terminal P2 and the first internal
  • the fifth switching circuit SW5 will conduct the electrical connection between the third input terminal P3 and the ground terminal GND
  • the sixth switching circuit SW6 will conduct the fourth input terminal P4 and the first internal node NS1.
  • the twenty-third switching circuit SW23 conducts the electrical connection between the fifth input terminal P5 and the first input terminal NI1 of the differential integrating circuit 210
  • the twenty-fourth switching circuit SW24 conducts the electrical connection between The electrical connection between the sixth input terminal P6 and the ground terminal GND
  • the twenty-seventh switching circuit SW27 turns on the electrical connection between the seventh input terminal P7 and the second input terminal NI2 of the differential integration circuit 210
  • the first The twenty-eighth switching circuit SW28 conducts the electrical connection between the eighth input terminal P8 and the ground terminal GND.
  • the switching circuits SW3, SW4, SW7, SW8, SW21, SW22, SW25, SW26, SW19, SW20, SW9 and SW10 are turned on when the corresponding control signals among the control signals K3, K4, K8 and K9 are at high potential
  • the corresponding electrical connections are turned off.
  • the detection operation may include a first stage ST1 and a second stage ST2, the first stage ST1 may include a first period TP1, a second period TP2 and a third period TP3, and the second stage ST2 may include a fourth period TP4, the fifth period TP5 and the sixth period TP6.
  • the detection circuit 200 can charge the first sensing capacitor C S1 to the operating voltage VDD, discharge the third sensing capacitor C S3 to the ground terminal GND, and then make the first sensing capacitor C S1 and the The internal charges of the third sensing capacitor C S3 are redistributed.
  • the fifth input terminal P5 is coupled to the first terminal of the third sensing capacitor C S3 and will be continuously coupled to the ground terminal GND, the first terminal of the third sensing capacitor C S3 is the first terminal of the third sensing capacitor C S3.
  • the outer plates of the three sensing capacitors C S3 will be in a grounded state.
  • both ends of the human body equivalent capacitance C B coupled to the first end of the third sensing capacitor C S3 will be in a grounded state , without causing a change in the sensing capacitance value of the third sensing capacitor C S3 . Therefore, when the first sensing capacitor C S1 and the third sensing capacitor C S3 are matched, the voltage of the first internal node NS1 will only be the same as that of the first sensing capacitor C when the human body is close to the first input terminal P1 It is related to the change of the human body equivalent capacitance C B connected in parallel with S1 . The conditions and operation details for matching the first sensing capacitor C S1 and the third sensing capacitor C S3 will be described later.
  • the detection circuit 200 can discharge the second sensing capacitor C S2 to the ground terminal GND, charge the fourth sensing capacitor C S4 to the operating voltage VDD, and then make the second sensing capacitor C The internal charges of S2 and the fourth sensing capacitor C S4 are redistributed.
  • the seventh input terminal P7 is coupled to the first terminal of the fourth sensing capacitor C S4 and is continuously coupled to the ground terminal GND, the first terminal of the fourth sensing capacitor C S4 is The outer plate of the fourth sensing capacitor CS4 will be in a grounded state.
  • both ends of the human body equivalent capacitor C B coupled to the first end of the fourth sensing capacitor C S4 will be in a grounded state, and will not A change in the sensing capacitance value of the fourth sensing capacitor C S4 is caused.
  • the second sensing capacitor C S2 matches the fourth sensing capacitor C S4
  • the voltage of the second internal node NS2 will only be the same as that of the second sensing capacitor C S2 when the human body is close to the third input terminal P3
  • the equivalent capacitance of the human body in parallel is related to the change of C B.
  • the differential integrator 210 performs integration through the first capacitor C1 and the second capacitor C2 according to the voltages of the first internal node NS1 and the second internal node NS2, respectively, the first internal node NS1 and the second internal node NS2
  • the voltage of the detected voltage signal VOUT will produce opposite changes, so that after the end of the first stage ST1, the change of the detected voltage signal VOUT will cause the first sensing capacitor C S1 and the second sensing capacitor C S2 with the equivalent capacitance of the human body. changes in the sensing capacitance value.
  • the detection circuit 200 can discharge the first sensing capacitor C S1 to the ground terminal GND, charge the third sensing capacitor C S3 to the operating voltage VDD, and then make the first sensing capacitor C S1 and the The internal charges of the third sensing capacitor C S3 are redistributed.
  • the voltage of the first internal node NS1 will only be related to the change of the human body equivalent capacitance CB connected in parallel with the third sensing capacitor C S3 when the human body approaches the third sensing capacitor C S3 .
  • the detection circuit 200 can charge the second sensing capacitor C S2 to the operating voltage VDD, discharge the fourth sensing capacitor C S4 to the ground terminal GND, and then make the second sensing capacitor C The internal charges of S2 and the fourth sensing capacitor C S4 are redistributed.
  • the third input terminal P3 is coupled to the first terminal of the second sensing capacitor C S2 and is continuously coupled to the ground terminal GND, if the second sensing capacitor C S2 and the first If the four sensing capacitors C S4 are matched, the voltage of the second internal node NS2 will only be related to the human body equivalent capacitance CB connected in parallel with the fourth sensing capacitor C S4 when the human body approaches the fourth sensing capacitor C S4 .
  • the differential integrator 210 performs integration through the first capacitor C1 and the second capacitor C2 according to the voltages of the first internal node NS1 and the second internal node NS2, respectively, the first internal node NS1 and the second internal node NS2
  • the voltage of the detected voltage signal VOUT will produce opposite changes, so that after the end of the second stage ST2, the change of the detected voltage signal VOUT will cause the third sensing capacitor C S3 and the fourth sensing capacitor C B with the equivalent capacitance C B of the human body. It is related to the change of the sensing capacitance value of C S4 .
  • the detection circuit 200 can detect the influence caused by the equivalent capacitance of the human body through the first sensing capacitor C S1 and the second sensing capacitor C S2 , and in the second stage ST2, The detection circuit 200 can detect the influence caused by the equivalent capacitance of the human body through the third sensing capacitor C S3 and the fourth sensing capacitor C S4 .
  • the detection voltage signal VOUT output by the detection circuit 200 will completely present the human body equivalent capacitance C B to the first sensing capacitance C S1 , the second sensing capacitance C S1 , the second sensing
  • the variation caused by the sensing capacitance values of the sensing capacitor C S2 , the third sensing capacitor C S3 and the fourth sensing capacitor C S4 improves the accuracy of touch detection according to the detection voltage signal VOUT.
  • both ends of the mutual capacitance C m2 between the second sensing capacitor C S2 and the third sensing capacitor C S3 will be at the same voltage, no charge will be stored , without affecting the detection result of the detection circuit 200 .
  • the mutual capacitance C m1 between the first sensing capacitor C S1 and the second sensing capacitor C S2 and the mutual capacitance C m3 between the third sensing capacitor C S3 and the fourth sensing capacitor C S4 will be at In opposite charging states, the influences caused by the mutual capacitances C m1 and C m3 will cancel each other out during the differential integration process, and therefore will not affect the detection voltage signal VOUT output by the detection circuit 200 .
  • the first sensing capacitor C S1 and the third sensing capacitor C S3 can cancel each other out due to the change of the sensing capacitor value due to the temperature and the influence of their fixed capacitance on the detection voltage signal VOUT
  • the second sensing capacitor C S3 C S2 and the fourth sensing capacitor C S4 can cancel each other due to the change of the sensing capacitance value caused by the temperature and the influence of their fixed capacitance on the detection voltage signal VOUT. Therefore, when the detection voltage signal VOUT is output, the detection circuit 200 has automatically eliminated the first detection voltage signal VOUT.
  • a sensing capacitor C S1 , a second sensing capacitor C S2 , a third sensing capacitor C S3 , and a fourth sensing capacitor C S4 are inherent capacitances themselves and errors in sensing capacitance value changes due to temperature. In this way, in the subsequent use of the analog-to-digital conversion circuit for numerical interpretation, there is no need to reserve space for the influence of temperature on the detection voltage signal VOUT. In other words, the entire input range of the analog-to-digital conversion circuit can be used. It is effectively used to interpret the changes caused by the equivalent capacitance of the human body, thereby increasing the range of effectively judging reading values, that is, to achieve the purpose of improving the effective sensing range.
  • the first switching circuit SW1 , the second switching circuit SW2 , the third switching circuit SW3 and the fourth switching circuit SW4 can charge the first sensing capacitor C S1 to the operating voltage VDD.
  • the fifth switching circuit SW5, the sixth switching circuit SW6, the seventh switching circuit SW7 and the eighth switching circuit SW8 can discharge the second sensing capacitor CS2 to the ground terminal GND.
  • the twenty-first switching circuit SW21, the twenty-second switching circuit SW22, the twenty-third switching circuit SW23, and the twenty-fourth switching circuit SW24 can enable the third sensing capacitor C S3 to be discharged to the ground terminal GND.
  • the twenty-fifth switching circuit SW25, the twenty-sixth switching circuit SW26, the twenty-seventh switching circuit S27, and the twenty-eighth switching circuit SW28 can charge the fourth sensing capacitor CS4 to the operating voltage VDD.
  • the nineteenth switching circuit SW19 can cut off the electrical connection between the first internal node NS1 and the first input terminal NI1 of the differential integration circuit 210
  • the twentieth switching circuit SW20 can cut off the second internal node NS2 and the differential integration circuit 210.
  • the ninth switching circuit SW9 can cut off the electrical connection between the first input terminal of the differential amplifier 212 and the first input terminal NI1 of the differential integrating circuit 210
  • the tenth switching circuit SW10 can cut off the second input terminal of the differential amplifier 212 and the first input terminal NI1 of the differential integrating circuit 210 .
  • Electrical connection between the second input terminals NI2 of the differential integration circuit 210 .
  • the third switching circuit SW3 can turn off the electrical connection between the first internal node NS1 and the operating voltage VDD, and the twenty-first switching circuit SW21 can turn off the differential integration circuit The electrical connection between the first input terminal NI1 of 210 and the ground terminal GND.
  • the nineteenth switching circuit SW19 can turn on the electrical connection between the first internal node NS1 and the first input end NI1 of the differential integrating circuit 210, so that the first sensing capacitor C S1 and the third sensing capacitor C S3
  • the electric charge in NS1 is redistributed, and the voltage VX1 of the first internal node NS1 can be expressed as Equation (12).
  • the first sensing capacitor C S1 and the third sensing capacitor C S3 match, for example, when the first sensing capacitor C S1 and the third sensing capacitor C S3 have the same intrinsic capacitance value, the first internal The voltage VX 1 of the node NS1 will be independent of the inherent capacitance values of the first sensing capacitor C S1 and the third sensing capacitor C S3 , and the equation (12) can be rewritten as the equation (13).
  • the voltage VX1 of the first internal node NS1 may be substantially equal to 1/2 times the operating voltage VDD.
  • the eighth switching circuit SW8 can cut off the electrical connection between the second internal node NS2 and the ground terminal GND, and the twenty-fifth switching circuit SW25 can cut off the second input of the differential integration circuit 210
  • the electrical connection between the terminal NI2 and the operating voltage VDD, and the twentieth switching circuit SW20 can turn on the electrical connection between the second internal node NS2 and the first input terminal NI1 of the differential integration circuit 210, so that the second inductive
  • the charges in the sensing capacitor CS2 and the fourth sensing capacitor CS4 are redistributed.
  • the voltage VX 2 of the second internal node NS2 will match the voltage between the second sensing capacitor C S2 and the fourth sensing capacitor C S4 Capacitance value is irrelevant.
  • the voltage VX 2 can be represented by equation (14).
  • the ninth switching circuit SW9 can turn on the electrical connection between the first input terminal of the differential amplifier 212 and the first input terminal NI1 of the differential integrating circuit 210, so as to A capacitor C1 performs integration, and the tenth switching circuit SW10 can conduct the electrical connection between the second input terminal of the differential amplifier 212 and the second input terminal NI2 of the differential integration circuit 210 to perform integration through the second capacitor C2.
  • the equivalent capacitance C B of the human body will cause the sensing capacitance value between the first input terminal P1 and the second input terminal P2 to change.
  • the voltage VX 1 of the first internal node NS1 also changes. It will change accordingly, causing part of the charge to move into or out of the first capacitor C1, and the transferred charge amount ⁇ QA1 can be expressed as Equation (15).
  • the fifth input terminal P5 is continuously coupled to the ground terminal GND in the first stage ST1
  • the first terminal of the third sensing capacitor C S3 is also coupled to the ground terminal GND, so as to be coupled to the ground terminal GND.
  • Both ends of the human body equivalent capacitance CB at the first end of the three sensing capacitors C S3 are in a grounded state without affecting the sensing capacitance value between the fifth input end P5 and the sixth input end P6.
  • the equivalent capacitance C B of the human body will be connected in parallel with the first end of the second sensing capacitor C S2 , so that the sensing capacitance value between the third input end P3 and the fourth input end P4
  • the voltage VX 2 of the second internal node NS2 will also change accordingly, causing some charges to move into or out of the second capacitor C2, where the transferred charge amount ⁇ QA2 can be expressed as equation (16).
  • the human body equivalent capacitance CB will not affect the connection between the seventh input terminal P7 and the eighth input terminal P8 Sense capacitance value.
  • the detection voltage signal VOUT output by the differential integration circuit 210 can be as shown in equation (17).
  • the first internal node NS1 will be at the operating voltage VDD, and the second internal node NS2 will be at the ground terminal GND.
  • the first input terminal NI1 of the differential integration circuit 210 is at the ground terminal GND, and the second input terminal NI2 of the differential integration circuit 210 is at the operating voltage VDD, so the charging directions of the mutual capacitances C m1 and C m3 are opposite. , the effects of the two can cancel each other, so it will not affect the detection operation.
  • the mutual capacitance C m2 is not shown in FIG. 5 , but since both ends of the mutual capacitance C m2 are coupled to the ground terminal GND, no charge is stored and the detection operation is not affected.
  • the first switching circuit SW1, the second switching circuit SW2, the third switching circuit SW3 and the fourth switching circuit SW4 can make the first sensing capacitor C S1 is discharged to the ground terminal GND.
  • the fifth switching circuit SW5, the sixth switching circuit SW6, the seventh switching circuit SW7 and the eighth switching circuit SW8 can make the second sensing capacitor CS2 be charged to the operating voltage VDD.
  • the twenty-first switching circuit SW21, the twenty-second switching circuit SW22, the twenty-third switching circuit, and the twenty-fourth switching circuit SW24 can charge the third sensing capacitor CS3 to the operating voltage VDD.
  • the twenty-fifth switching circuit SW25, the twenty-sixth switching circuit SW26, the twenty-seventh switching circuit SW27, and the twenty-eighth switching circuit SW28 can enable the fourth sensing capacitor CS4 to be discharged to the ground terminal.
  • the nineteenth switching circuit SW19 can cut off the electrical connection between the first internal node NS1 and the first input terminal NI1 of the differential integrating circuit 210
  • the twentieth switching circuit SW20 can cut off the second internal node NS2 and the differential integrating circuit
  • the electrical connection between the second input terminal NI2 of the The switching circuit SW10 can turn off the electrical connection between the second input terminal of the differential amplifier 212 and the second input terminal NI2 of the differential integrating circuit 210 .
  • the fourth switching circuit SW4 can turn off the electrical connection between the first internal node NS1 and the ground terminal GND, and the twenty-second switching circuit SW22 can turn off the differential integration circuit
  • the electrical connection between the first input terminal NI1 of 210 and the operating voltage VDD, and the nineteenth switching circuit SW19 can turn on the electrical connection between the first internal node NS1 and the first input terminal NI1 of the differential integration circuit 210 , the charges in the first sensing capacitor C S1 and the third sensing capacitor C S3 are redistributed, and the voltage VX 1 of the first internal node NS1 can be expressed as equation (18).
  • the first sensing capacitor C S1 and the third sensing capacitor C S3 match, for example, when the first sensing capacitor C S1 and the third sensing capacitor C S3 have the same intrinsic capacitance value, the first internal The voltage VX 1 of the node NS1 will be independent of the intrinsic capacitance values of the first sensing capacitor C S1 and the third sensing capacitor C S3 , and the equation (18) can be rewritten as the equation (19).
  • the voltage VX1 of the first internal node NS1 may be substantially equal to 1/2 times the operating voltage VDD.
  • the seventh switching circuit SW7 can cut off the electrical connection between the second internal node NS2 and the operating voltage VDD
  • the twenty-sixth switching circuit SW26 can cut off the second input of the differential integration circuit 210
  • the electrical connection between the terminal NI2 and the ground terminal GND, and the twentieth switching circuit SW20 can turn on the electrical connection between the second internal node NS2 and the second input terminal NI2 of the differential integration circuit 210, so that the second inductance
  • the charges in the sensing capacitor CS2 and the fourth sensing capacitor CS4 are redistributed.
  • the voltage VX 2 of the second internal node NS2 will match the voltage between the second sensing capacitor C S2 and the fourth sensing capacitor C S4 Capacitance value is irrelevant.
  • the voltage VX 2 can be represented by equation (20).
  • the ninth switching circuit SW9 may turn on the electrical connection between the first input terminal of the differential amplifier 212 and the first input terminal NI1 of the differential integrating circuit 210, so as to A capacitor C1 performs integration, and the tenth switching circuit SW10 can turn on the electrical connection between the second input terminal of the differential amplifier 212 and the second input terminal NI2 of the differential integration circuit 210 to perform integration through the second capacitor C2, and The first output terminal and the second output terminal of the differential amplifier 212 can output the detection voltage signal VOUT.
  • the equivalent capacitance C B of the human body will be connected in parallel with the third sensing capacitor C S3 , so that the sensing capacitance value between the fifth input terminal P5 and the sixth input terminal P6 changes.
  • the voltage VX 1 of the first internal node NS1 will also change accordingly, causing some charges to move into or out of the first capacitor C1 , and the transferred charge amount ⁇ QA1 can be expressed as equation (21).
  • the equivalent capacitance C B of the human body will not affect the connection between the first input terminal P1 and the second input terminal P2. Sense capacitance value.
  • the equivalent capacitance C B of the human body will be connected in parallel with the fourth sensing capacitor C S4 , so that the sensing capacitance value between the seventh input terminal P7 and the eighth input terminal P8 changes.
  • the voltage VX 2 of the second internal node NS2 will also change accordingly, causing part of the charges to move into or out of the second capacitor C2, where the transferred charge amount ⁇ QA2 can be expressed as equation (22).
  • the human body equivalent capacitance CB will not affect the connection between the third input terminal P3 and the fourth input terminal P4. Sense capacitance value.
  • the detection voltage signal VOUT output by the differential integrating circuit 210 can be as shown in equation (23).
  • the first internal node NS1 will be at the ground terminal GND, and the second internal node NS2 will be at the operating voltage VDD.
  • the first input terminal NI1 of the differential integration circuit 210 is at the operating voltage VDD
  • the second input terminal NI2 of the differential integration circuit 210 is at the ground terminal GND, so the charging directions of the mutual capacitances C m1 and C m3 are opposite. , the effects of the two on the detection operation can cancel each other out.
  • both ends of the mutual capacitance C m2 are coupled to the operating voltage VDD, so that no charge is stored and the detection operation is not affected.
  • the detection circuit provided by the embodiments of the present application can control the switching circuit, so that the mutual capacitances between different sensing capacitors can cancel each other or have no effect, so the accuracy of the detection circuit can be improved.
  • the detection circuit of the present application can also use different sensing capacitors to offset errors caused by external common mode interference such as temperature, so that the detection voltage signal is only related to the equivalent capacitance of the human body, thereby increasing the range of effective judgment values. To achieve the purpose of improving the effective sensing range.
  • the present application also provides a chip and an electronic device, such as an earphone. Since the voltage detection signal generated by the detection circuit in the chip and the electronic device can accurately show the change of the sensing capacitance value when the human body approaches, without being interfered by the temperature change and mutual capacitance, it can be used for capacitive detection. Touch detection, capacitive in-ear detection, capacitive pressure detection, etc., and the chip and electronic device of the present application can perform subsequent operations, such as answering a call, playing or pausing music, etc., according to different applications.

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Abstract

本申请公开了一种检测电路、芯片及相关电子装置，检测电路包括第一至第四输入端、第一至第八切换电路及差分积分电路。第一至第八切换电路用以在检测操作中使第一感测电容及第二感测电容充电及放电，以在检测操作中消除第一感测电容及第二感测电容之间的第一互容对检测电压信号的影响，使得差分积分电路依据第一感测电容及第二感测电容的感测电容值输出与人体接近有关的检测电压信号。

Description

检测电路、芯片及相关电子装置 技术领域
本申请是有关于一种检测电路，尤其涉及一种电容检测电路、芯片及相关电子装置。
背景技术
在耳机、手机、车载触控等应用场景中，常会检测电容来配合检测算法来完成各种基于电容的应用场景中的人机交互。例如，根据电容检测结果来检测耳机的佩戴状态，进而控制是否播放音乐；例如根据电容检测结果来判断用户作用于手机上的压力，进而判断用户的手势和控制手机的操作等。然而，外部的干扰及温度的变化常会导致感测电容的感测电容值产生变化，而在应用中造成错误的判断。
在现有技术中，会将单一的感测电容分为两个邻近的感测电容，并以差分的形式进行感测，以减少外部共模噪声的干扰。然而，邻近的感测电容之间会产生互容，且互容会在感测的过程中参与电荷转移，导致感测结果失准。此外，人体靠近或接触感测电容时，互容的变化会与感测电容值的变化相反，使电容感测结果更加难以判读。因此，如何减少温度等外界干扰及感测电容之间的互容的影响，使得电容感测更为精准，已成为本领域有待解决的问题之一。
发明内容
本申请的目的之一在于公开一种检测电路、芯片及相关电子装置，来解决上述问题。
本申请的一实施例提供一种检测电路，检测电路包括第一至第四 输入端、差分积分电路及第一至第八切换电路。所述第一输入端，耦接于第一感测电容的第一端。所述第二输入端，耦接于所述第一感测电容的第二端，所述第一感测电容具有第一固有电容值，且所述第一感测电容的感测电容值至少因人体接近所述第一感测电容的所述第一端而改变。所述第三输入端，耦接于第二感测电容的第一端。所述第四输入端，耦接于所述第二感测电容的第二端，所述第二感测电容具有第二固有电容值，且所述第二感测电容的感测电容值至少因人体接近所述第二感测电容的所述第一端而改变。所述差分积分电路，用以在检测电路执行检测操作时，根据第一内部节点的电压及第二内部节点的电压进行积分以产生检测电压信号。所述第一切换电路，具有第一端、第二端及第三端，其中所述第一内部节点是指所述第一切换电路的所述第一端，所述第一切换电路的所述第二端耦接于所述检测电路的所述第一输入端，及所述第一切换电路的所述第三端耦接于接地端，所述第一切换电路用以导通或截止所述检测电路的所述第一输入端与所述第一内部节点之间的电性连接，及导通或截止所述检测电路的所述第一输入端与所述接地端之间的电性连接。所述第二切换电路，耦接于所述检测电路的所述第二输入端、所述第一内部节点及所述接地端，所述第二切换电路用以导通或截止所述检测电路的所述第二输入端与所述第一内部节点之间的电性连接，及导通或截止所述检测电路的所述第二输入端与所述接地端之间的电性连接。所述第三切换电路，耦接于所述第一内部节点及操作电压，所述第三切换电路用以导通或截止所述第一内部节点及所述操作电压之间的电性连接。所述第四切换电路，耦接于所述第一内部节点及所述接地端，所述第四切换电路用以导通或截止所述第一内部节点及所述接地端之间的电性连接。所述第五切换电路，具有第一端、第二端及第三端，其中所述第二内部节点是指所述第五切换电路的所述第一端，所述第五切换电路的所述第二端耦接于所述检测电路的所述第三输入端，及所述第五切换电路的所述第二端耦接于所述接地端，所述第五切换电路用以导通或截止所述检测电路的所述第三输入端与所述第二内部节点之间的电性连接，及导通或截止所述检测电路的所述第三输入端与所述 接地端之间的电性连接。所述第六切换电路，耦接于所述检测电路的所述第四输入端、所述第二内部节点及所述接地端，所述第六切换电路用以导通或截止所述检测电路的所述第四输入端与所述第二内部节点之间的电性连接，及导通或截止所述检测电路的所述第四输入端与所述接地端之间的电性连接。所述第七切换电路，耦接于所述第二内部节点及所述操作电压，所述第七切换电路用以导通或截止所述第二内部节点及所述操作电压之间的电性连接。所述第八切换电路，耦接于所述第二内部节点及所述接地端，所述第八切换电路用以导通或截止所述第二内部节点及所述接地端之间的电性连接。
所述第一切换电路、所述第二切换电路、所述第三切换电路、所述第四切换电路、所述第五切换电路、所述第六切换电路、所述第七切换电路及所述第八切换电路用以在所述检测操作中使所述第一感测电容及所述第二感测电容进行充电或放电以消除所述第一感测电容及所述第二感测电容之间的第一互容对所述检测电压信号的影响，使得所述差分积分电路依据所述第一感测电容及所述第二感测电容的感测电容值输出与人体接近有关的所述检测电压信号。
本申请的另一实施例提供一种芯片，所述芯片包括所述检测电路及用于读取所述检测电路输出的所述检测电压信号读取电路。
本申请的另一实施例提供一种电子装置，包括所述的检测电路。
本申请的检测电路、芯片及相关电子装置能够减少温度等外界共模信号的干扰及感测电容之间的互容的干扰，使检测电路检测的电容信号的准确度得以提升。
附图说明
图1是电容式入耳检测的示意图。
图2是电容式入耳检测的另一示意图。
图3是本申请一实施例的检测电路的示意图。
图4是图3的检测电路在执行检测操作时所接收到的信号和输出的信号的时序图。
图5是本申请另一实施例的检测电路的示意图。
图6是图5的检测电路在执行检测操作时所接收到的信号和输出的信号的时序图。
图7是图5中，各感测电容的设置关系图。
具体实施方式
以下揭示内容提供了多种实施方式或例示，其能用以实现本揭示内容的不同特征。
图1是电容式入耳检测的示意图。在图1中，耳机上的自容C SF的第一端可以是耳机机壳上的外侧极板ET，而自容C SF的第二端可以是耳机机壳上的内侧极板IT。因此，当有人佩戴耳机时，耳朵会与外侧极板ET接触，此时人体的人体等效电容C B会通过外侧极板ET与自容C SF并联。在图1中，外侧极板ET接入读取电路SC，而内侧极板IT接地。此时读取电路SC读取到的电压会与外界温度所引起的电容变化以及人体接近时与自容C SF并联的人体等效电容C B有关，因此通过读取电路SC所读取到的电压，就可以判断是否有人体接近耳机，从而达成入耳检测。
一般来说，在读取电路SC读取自容C SF的第一端的电压之前，系统中的充电器会先对自容C SF的第一端充电，然而若充电器受到干扰，就可能会导致整个系统的地电压也连带受到干扰，从而产生共模噪声。为了减少共模噪声所造成的误差，先前技术会将自容C SF拆分成两个小的自容。图2是电容式入耳检测的另一示意图。在图2中，原先的自容C SF被拆分成两个小的自容C SF1及C SF2。在此情况下，若以差分的方式读取自容C SF1及C SF2上的电压，就可以消除掉因充电器被干扰所造成的共模噪声。然而，自容C SF1及C SF2之间会产生互容C m，且当人体接近或有温度变化时，互容C m与自容C SF1及C SF2 的感测电容值会对读取电压造成相反的影响，举例来说，当人体接近自容C SF1及C SF2时，自容C SF1及C SF2的感测电容值会变大，而互容C m则会变小，使得读取电路SC所读取到的电压难以直接地呈现出人体接近时所造成的变化，也使得电容式入耳检测的结果较不精准。
图3是本申请一实施例的检测电路100的示意图。在图3的实施例中，检测电路100可耦接于第一感测电容C S1及第二感测电容C S2，第一感测电容C S1及第二感测电容C S2本身虽具有固定的电容值，然而当有人体接近或有温度变化时，检测电路100所感测到的第一感测电容C S1及第二感测电容C S2的感测电容值将会有所变化，因此检测电路100可通过第一感测电容C S1及第二感测电容C S2进行电容变化的检测以输出对应的检测电压信号VOUT。
举例来说，当人体接近第一感测电容C S1及第二感测电容C S2时，人体的人体等效电容C B会与第一感测电容C S1及第二感测电容C S2并联，此时第一感测电容C S1及第二感测电容C S2的感测电容值会产生变化，而检测电压信号VOUT的值也会对应地改变。其中，所述人体接近第一感测电容C S1及第二感测电容C S2包括人体靠近或接触第一感测电容C S1及第二感测电容C S2。
此外，本申请的检测电路100可以消除第一感测电容C S1及第二感测电容C S2之间的互容C m对检测电压信号VOUT所造成的影响，使检测电压信号VOUT能够更精准地用来判断是否有人体接近第一感测电容C S1及第二感测电容C S2，因此在依据检测电压信号VOUT进行电容式触摸检测时，也可以更加精准，其细节说明如下。
在图3中，检测电路100可设置在电子装置10的机壳(未绘示于图中)中，也就是说，所述机壳可包覆检测电路100。在此情况下，第一感测电容C S1及第二感测电容C S2可例如但不限于是所述机壳的至少一部分上的电极所形成的自电容，其中机壳上的电极可以是壳体上既有的导电件，或是在壳体上专门设置的电极。
虽然第一感测电容C S1及第二感测电容C S2本身都具有固有的电容值，然而当有人体接近第一感测电容C S1及第二感测电容C S2时， 第一感测电容C S1及第二感测电容C S2的感测电容值则会随之改变。举例来说，第一感测电容C S1及第二感测电容C S2的第一端可以位于所述机壳的至少一部分的外侧，而第一感测电容C S1及第二感测电容C S2的第二端可以位于所述机壳的至少一部分的内侧。也就是说，第一感测电容C S1及第二感测电容C S2的第一端可以是机壳的外侧极板，而第一感测电容C S1及第二感测电容C S2的第二端可以是机壳的内侧极板。如此一来，当人体接近所述机壳时，人体的人体等效电容C B会与第一感测电容C S1的第一端及第二感测电容C S2的第一端相耦接，使得第一感测电容C S1及第二感测电容C S2的感测电容值产生变化。此外，本申请并不限定第一感测电容C S1及第二感测电容C S2的是由所述机壳形成的自容，在有些其他实施例中，根据使用情境的不同，第一感测电容C S1及第二感测电容C S2的也可能是电子装置10中其他部件所形成的自容。
检测电路100可包括第一输入端P1、第二输入端P2、第三输入端P3、第四输入端P4、第一切换电路SW1、第二切换电路SW2、第三切换电路SW3、第四切换电路SW4、第五切换电路SW5、第六切换电路SW6、第七切换电路SW7、第八切换电路SW8及差分积分电路110。
第一输入端P1可耦接于第一感测电容C S1的第一端，而第二输入端P2可耦接于第一感测电容C S1的第二端。第三输入端P3可耦接于第二感测电容C S2的第一端，而第四输入端P4可耦接于第二感测电容C S2的第二端。在本实施例中，检测电路100是通过第一输入端P1和第二输入端P2来感测第一感测电容C S1的感测电容值，并通过第三输入端P3和第四输入端P4来感测第二感测电容C S2的感测电容值。
第一切换电路SW1具有第一端、第二端及第三端，在本申请中，为方便说明，是将第一切换电路SW1的第一端另外命名为第一内部节点NS1。第一切换电路SW1的第二端可耦接于第一输入端P1而第一切换电路SW1的第三端可耦接于接地端GND，第一切换电路SW1可导通或截止第一输入端P1与第一内部节点NS1之间的电性连接， 并可导通或截止第一输入端P1与接地端GND之间的电性连接。
第二切换电路SW2可耦接于第二输入端P2、第一内部节点NS1及接地端GND，第二切换电路SW2可导通或截止第二输入端P2与第一内部节点NS1之间的电性连接，并可导通或截止第二输入端P2与接地端GND之间的电性连接。
第三切换电路SW3可耦接于第一内部节点NS1及操作电压VDD，第三切换电路SW3可导通或截止第一内部节点NS1及操作电压VDD之间的电性连接。在本申请中，操作电压VDD可大于接地端GND的电压，例如但不限于是检测电路100所在系统中所提供的供电电压或参考电压。
第四切换电路SW4可耦接于第一内部节点NS1及接地端GND，第四切换电路SW4可导通或截止第一内部节点NS1及接地端GND之间的电性连接。
第五切换电路SW5具有第一端、第二端及第三端，以下为方便说明，将第五切换电路SW5的第一端另外命名为第二内部节点NS2。第五切换电路SW5的第二端可耦接于第三输入端P3，而第五切换电路SW5的第三端可耦接于接地端GND，第五切换电路SW5可以导通或截止第三输入端P3与第二内部节点NS2之间的电性连接，并可导通或截止第三输入端P3与接地端GND之间的电性连接。
第六切换电路SW6可耦接于第四输入端P4、第二内部节点NS2及接地端GND，第六切换电路SW6可以导通或截止第四输入端P4与第二内部节点NS2之间的电性连接，并可导通或截止第四输入端P4与接地端GND之间的电性连接。
第七切换电路SW7可耦接于第二内部节点NS2及操作电压VDD，第七切换电路SW7可以导通或截止第二内部节点NS2及操作电压VDD之间的电性连接。第八切换电路SW8可耦接于第二内部节点NS2及接地端GND，第八切换电路SW8可以导通或截止第二内部节点NS2及接地端GND之间的电性连接。
差分积分电路110具有第一输入端NI1及第二输入端NI2。在图3中，差分积分电路110的第一输入端NI1可耦接于第一内部节点NS1， 而差分积分电路110的第二输入端NI2可耦接于第二内部节点NS2。如此一来，在检测电路100执行检测操作时，差分积分电路110便可根据第一内部节点NS1及第二内部节点NS2的电压进行积分以产生检测电压信号VOUT。
在本实施例中，差分积分电路110可包括差分放大器112、第一电容C1、第二电容C2、第九切换电路SW9及第十切换电路SW10。
差分放大器112具有第一输入端、第二输入端、第一输出端及第二输出端。在本实施例中，差分放大器112的第一输入端可以是正输入端，差分放大器112的第二输入端可以是负输入端，差分放大器112的第一输出端可以是正输出端并可输出正输出电压VPO，而差分放大器112的第二输出端可以是负输出端并可输出负输出电压VNO，而差分放大器112的第一输出端及第二输出端可以共同输出检测电压信号VOUT。
第一电容C1耦接于差分放大器112的第一输入端与差分放大器112的第一输出端之间。第二电容C2耦接于差分放大器112的第二输入端及差分放大器112的第二输出端之间。
第九切换电路SW9可耦接于差分放大器112的第一输入端及差分积分电路110的第一输入端NI1之间，第九切换电路SW9可导通或截止差分放大器112的第一输入端及差分积分电路110的第一输入端NI1之间的电性连接。第十切换电路SW10可耦接于差分放大器112的第二输入端及差分积分电路110的第二输入端NI2之间，第十切换电路SW10可导通或截止差分放大器112的第二输入端及差分积分电路110的第二输入端NI2之间的电性连接。
在本实施例中，通过控制第一切换电路SW1至第十切换电路SW10，检测电路100就可以通过差分的方式感测第一感测电容C S1及第二感测电容C S2的感测电容值，并据以输出检测电压信号VOUT，因此可以减少外部环境的共模噪声对检测电压信号的检测结果的干扰。此外，在检测操作的过程中，通过适当地控制第一至第十切换电路，还可以使第一感测电容C S1及第二感测电容C S2处于相同的充电状态，并使第一内部节点NS1及第二内部节点NS2处在相同的电压， 此时第一感测电容C S1及第二感测电容C S2之间的互容C m的两端将处于相同的电位，因此不会储存电荷，使得检测电压信号VOUT不会受到互容C m的影响，也就是说，检测电压信号VOUT不会因为互容C m的大小而产生变化，从而在依据检测电压信号VOUT进行电容检测时可以得到较为准确的结果。所述的电容检测的应用有很多种，例如：在耳机中常会使用的电容式入耳检测来实现耳机的佩戴/脱落检测进而控制耳机是否进行音乐播放等各种操作，以及使用电容式的触碰检测来实现单击、双击、滑动等手势识别，进而完成各种应用场景中的人机交互。
然而，当温度变化时，第一感测电容C S1及第二感测电容C S2的感测电容值也会产生变化，也就是温漂的现象。在本实施例中，为了减少检测电压信号VOUT受到温度以及第一感测电容C S1及第二感测电容C S2本身的固有电容值的影响而导致可有效判读数值的范围缩小，检测电路100还可包括第三电容C3、第四电容C4及第十一至第十八切换电路(SW11至SW18)，以抵消第一感测电容C S1及第二感测电容C S2本身的固有电容值对检测电压信号VOUT所造成的影响，以及抵消因温度变化导致第一感测电容C S1及第二感测电容C S2的感测电容值变化时，对检测电压信号VOUT所造成的影响。
第三电容C3具有第一端及第二端。第十一切换电路SW11可导通或截止第三电容C3的第一端与接地端GND之间的电性连接。第十二切换电路SW12可导通或截止第三电容C3的第一端与操作电压VDD之间的电性连接。第十三切换电路S13可导通或截止第三电容C3的第二端与接地端GND之间的电性连接，并可导通或截止第三电容C3的第二端与操作电压VDD之间的电性连接。第十四切换电路S14可导通或截止第三电容C3的第一端与第一内部节点NS1间的电性连接。
第四电容C4具有第一端及第二端。第十五切换电路SW15可导通或截止第四电容C4的第一端与接地端GND之间的电性连接。第十六切换电路SW16可导通或截止第四电容C4的第一端与操作电压 VDD之间的电性连接。第十七切换电路SW17可导通或截止第四电容C4的第二端与接地端GND之间的电性连接，并可导通或截止第四电容C4的第二端与操作电压VDD之间的电性连接。第十八切换电路SW18可导通或截止第四电容C4的第一端与第二内部节点NS2间的电性连接。
在本实施例中，第一切换电路SW1可包括第一开关S1及第二开关S2。第一开关S1具有第一端、第二端及控制端，第一开关S1的第一端耦接于第一输入端P1，第一开关S1的第二端即为第一内部节点NS1。第二开关S2具有第一端、第二端及控制端，第二开关S2的第一端耦接于第一输入端P1，第二开关S2的第二端耦接于接地端GND。
第二切换电路SW2可包括第三开关S3及第四开关S4。第三开关S3具有第一端、第二端及控制端，第三开关S3的第一端耦接于第二输入端P2，第三开关S3的第二端耦接于第一内部节点NS1。第四开关S4具有第一端、第二端及控制端，第四开关S4的第一端耦接于第二输入端P2，第四开关的第二端耦接于接地端GND
第五切换电路SW5包括第五开关S5及第六开关S6。第五开关S5具有第一端、第二端及控制端，第五开关S5的第一端耦接于第三输入端P3，第五开关S5的第二端即为第二内部节点NS2。第六开关S6具有第一端、第二端及控制端，第六开关S6的第一端耦接于第三输入端P3，第六开关S6的第二端耦接于接地端GND。
第六切换电路SW6包括第七开关S7及第八开关S8。第七开关S7具有第一端、第二端及控制端，第七开关S7的第一端耦接于第四输入端P4，第七开关S7的第二端耦接于第二内部节点NS2。第八开关S8具有第一端、第二端及控制端，第八开关S8的第一端耦接于第四输入端P4，第八开关S8的第二端耦接于接地端GND。
第十三切换电路SW13包括第九开关S9及第十开关S10。第九开关S9具有第一端、第二端及控制端，第九开关S9的第一端耦接于第三电容C3的第二端，第九开关S9的第二端耦接于操作电压VDD。 第十开关S10具有第一端、第二端及控制端，第十开关S10的第一端耦接于第三电容C3的第二端，第十开关S10的第二端耦接于接地端GND。
第十七切换电路SW17包括第十一开关S11及第十二开关S12。第十一开关S11具有第一端、第二端及控制端，第十一开关S11的第一端耦接于第四电容C4的第二端，第十一开关S11的第二端耦接于操作电压VDD。第十二开关S12具有第一端、第二端及控制端，第十二开关S12的第一端耦接于第四电容C4的第二端，第十二开关S12的第二端耦接于接地端GND。
此外，第三切换电路SW3、第四切换电路SW4、第七切换电路SW7、第八切换电路SW8、第九切换电路SW9、第十切换电路SW10、第十一切换电路SW11、第十二切换电路SW12、第十四切换电路SW14、第十五切换电路SW15、第十六切换电路SW16及第十八切换电路SW18可由单一开关来实现。
第一切换电路SW1至第十八切换电路SW8可以用来使第一感测电容C S1、第三电容C3、第二感测电容C S2及第四电容C4在不同的时段中分别进行充电、放电或使电荷重新分配的操作，从而更有效率而便利地执行检测操作。
在图3中，第一切换电路SW1、第二切换电路SW2、第五切换电路SW5及第六切换电路SW6可由第一控制信号K1及第二控制信号K2来控制，第三切换电路SW3、第七切换电路SW7、第十一切换电路SW11及第十五切换电路SW15可根据第三控制信号K3来控制。第四切换电路SW4、第八切换电路SW8、第十二切换电路SW12及第十六切换电路SW16可根据第四控制信号K4来控制。第十三切换电路SW13可根据第五控制信号K5及第六控制信号K6来控制，而第十七切换电路SW17也可根据第五控制信号K5及第六控制信号K6来控制。第十四切换电路SW14及第十八切换电路SW18可根据第七控制信号K7来控制，而第九切换电路SW9及第十切换电路SW10可根据第八控制信号K8来控制。
图4是检测电路100在执行检测操作时所接收到的信号时序图。在有些实施例中，当控制信号K1处于高电位时，第一切换电路SW1会导通第一输入端P1与第一内部节点NS1之间的电性连接，第二切换电路SW2会导通第二输入端P2与接地端GND之间的电性连接，第五切换电路SW5会导通第三输入端P3与接地端GND之间的电性连接，而第六切换电路SW6会导通第四输入端P4与第二内部节点NS2之间的电性连接。当控制信号K2处于高电位时，第一切换电路SW1会导通第一输入端P1与接地端GND之间的电性连接，第二切换电路SW2会导通第二输入端P2与第一内部节点NS1之间的电性连接，第五切换电路SW5会导通第三输入端P3与第二内部节点NS2之间的电性连接，而第六切换电路SW6会导通第四输入端P4与接地端GND之间的电性连接。
当控制信号K5处于高电位时，第十三切换电路SW13会导通第三电容C3的第二端与操作电压VDD之间的电性连接，而第十七切换电路SW17会导通第四电容C4的第二端与操作电压VDD之间的电性连接。当控制信号K6处于高电位时，第十三切换电路SW13会导通第三电容C3的第二端与接地端GND之间的电性连接，而第十七切换电路SW17会导通第四电容C4的第二端与接地端GND之间的电性连接。
此外，切换电路SW3、SW4、SW7、SW8、SW9、SW10、SW11、SW12、SW14、SW15及SW16会在控制信号K3、K4、K7及K8中对应的控制信号处于高电位时，导通对应的电性连接，并在控制信号K3、K4、K7及K8中对应的控制信号处于低电位时，截止对应的电性连接。
在图4中，检测操作可包含第一阶段ST1及第二阶段ST2，第一阶段ST1可包含第一时段TP1、第二时段TP2及第三时段TP3，而第二阶段ST2可包含第四时段TP4、第五时段TP5及第六时段TP6。
在第一阶段ST1中，检测电路100可将第一感测电容C S1及第三电容C3分别充电至操作电压VDD，并使第一感测电容C S1及第三电 容C3共同耦接至第一内部节点NS1，使得第一感测电容C S1及第三电容C3的内部电荷可进行重新分配。在第一感测电容C S1与第三电容C3相匹配的情况下，第一内部节点NS1的电压将只会与人体接近第一感测电容C S1，也就是第一感测电容C S1的外侧极板时，与第一感测电容C S1的第一端并联的人体等效电容以及因为温度而引起的感测电容值变化有关，而与第一感测电容C S1本身的固有电容值及第三电容C3的电容值无关，也就是说，第一内部节点NS1的电压不会因为第一感测电容C S1本身的固有电容值及第三电容C3的电容值的大小而改变。关于第一感测电容C S1与第三电容C3相匹配的条件及操作细节将说明于后。
此外，在第一阶段ST1中，检测电路100可将第二感测电容C S2及第四电容C4分别充电至操作电压VDD，并使第二感测电容C S2及第四电容C4共同耦接至第二内部节点NS2，使得第二感测电容C S2及第四电容C4的内部电荷可进行重新分配。由于在第一阶段ST1中，第三输入端P3会持续地耦接至接地端GND，因此第二感测电容C S2的第一端，也就是第二感测电容C S2的外侧极板会处于接地状态。由于人体一般是处于接地状态，因此当人体接近第二感测电容C S2时，耦接至第二感测电容C S2的第一端的人体等效电容C B的两端都将处于接地状态，而不会造成第二感测电容C S2的感测电容值的变化。在此情况下，若第二感测电容C S2与第四电容C4相匹配，则第二内部节点NS2的电压将只会与因为温度所引起的电容变化有关，而与第二感测电容C S2本身的固有电容值及第四电容C4的电容值无关，也就是说，第二内部节点NS2的电压不会因为第二感测电容C S2本身的固有电容值及第四电容C4的电容值的大小而改变。
再者，由于差分积分器110会根据第一内部节点NS1及第二内部节点NS2的电压，分别通过第一电容C1及第二电容C2进行积分，因此两者在检测电压信号VOUT中会造成相反的影响，使得第一感测电容C S1及第二感测电容C S2因温度所导致的感测电容值变化可以互相抵消，并使得检测电压信号VOUT只会与人体接近时，第一感测电容C S1的电容感测值变化有关。
在第二阶段ST2中，检测电路100可将第一感测电容C S1放电至接地端GND，并使第三电容C3充电至操作电压VDD，再使第一感测电容C S1及第三电容C3共同耦接至第一内部节点NS1，使得第一感测电容C S1及第三电容C3的内部电荷可进行重新分配。在第二阶段ST2中，由于第一输入端P1会持续地耦接至接地端GND，因此第一感测电容C S1的第一端，也就是第一感测电容C S1的外侧极板会处于接地状态，且由于人体一般是处于接地状态，因此当人体接近第一感测电容C S1时，耦接至第一感测电容C S1的第一端的人体等效电容C B的两端都将处于接地状态，而不会造成第一感测电容C S1的感测电容值的变化。在此情况下，若第一感测电容C S1与第三电容C3相匹配，则第一内部节点NS1的电压将只会与因为温度所引起的电容值变化有关，而与第一感测电容C S1本身的固有电容值及第三电容C3的电容值无关。
此外，在第二阶段ST2中，检测电路100可将第二感测电容C S2放电至接地端，并使第四电容C4充电至操作电压VDD，再使第二感测电容C S2及第四电容C4共同耦接至第二内部节点NS2，使得第二感测电容C S2及第四电容C4的内部电荷可进行重新分配。在此情况下，若第二感测电容C S2与第四电容C4相匹配，则第二内部节点NS2的电压将只会与人体接近第二感测电容C S2时，与第二感测电容C S2的第一端并联的人体等效电容及因为温度而引起的感测电容值变化有关，而与第二感测电容C S2本身的固有电容值及第四电容C4的电容值无关。
再者，由于差分积分器110会根据第一内部节点NS1及第二内部节点NS2的电压，分别通过第一电容C1及第二电容C2进行积分，因此两者会使检测电压信号VOUT产生相反的变化，使得第一感测电容C S1及第二感测电容C S2因温度所导致的感测电容值变化可以互相抵消，并使得检测电压信号VOUT只会与人体接近引起的感测电容值变化有关。
在第一阶段ST1中，检测电路100可以通过第一感测电容C S1检 测到人体等效电容所造成的影响，而在第二阶段ST2中，检测电路100可通过第二感测电容C S2检测到人体等效电容所造成的影响，。如此一来，在第一阶段ST1及第二阶段ST2结束后，检测电路100所输出的检测电压信号VOUT将会包括通过第一感测电容C S1及第二感测电容C S2所检测到的人体等效电容变化，因此可以完整地呈现出人体等效电容的变化，从而提升触碰检测的准确度。
在第一阶段ST1中，当第一感测电容C S1及第三电容C3进行充电及当第二感测电容C S2及第四电容C4进行充电时，第一内部节点NS1及第二内部节点NS2会处于相同的电压，因此第一感测电容C S1及第二感测电容C S2之间的互容C m的两端将处于相同的电位，在此情况下，互容C m不会储存电荷。同理，在第二阶段ST2中，当第一感测电容C S1及第三电容C3进行充电及当第二感测电容C S2及第四电容C4进行充电时，第一内部节点NS1及第二内部节点NS2会处于相同的电压，因此互容C m不会储存电荷。因此，检测电路100输出的检测电压信号VOUT几乎不受互容C m的影响，进而使得检测电压信号VOUT能够更加精准地呈现出因为人体接近时，对第一感测电容C S1及第二感测电容C S2的感测电容值所造成的变化，而在依据检测电压信号VOUT进行触碰检测时也可以得到较为准确的结果。
此外，在有些实施例中，检测电路100所输出的检测电压信号VOUT会被提供至读取电路，例如模拟数字转换电路(analog-digital converter)来进行数值的判读，因此检测电路100可以根据模拟数字转换电路所需的电压规格，连续执行多次的检测操作，以将检测电压信号VOUT逐步积分至适合模拟数字转换电路操作的预定检测范围。在本申请的有些实施例中，芯片可包括检测电路100及读取电路。
再者，由于检测电路100在输出检测电压信号VOUT时，已经自动对温度所导致的电容值变化进行抵消，因此在后续使用模拟数字转换电路进行数值的判读时，就不需预留空间给温度对检测电压信号VOUT所造成的影响，换句话说，模拟数字转换电路的整个输入范围都可以有效地用来判读人体等效电容所造成的变化，从而增加可有效 判读数值的范围，达到提高有效感测范围的目的。
在图4的第一时段TP1中，第一切换电路SW1可导通第一输入端P1与第一内部节点NS1之间的电性连接，并可截止第一输入端P1与接地端GND之间的电性连接。第二切换电路SW2可截止第二输入端P2与第一内部节点NS1之间的电性连接，并可导通第二输入端P2与接地端GND之间的电性连接。第三切换电路SW3可导通第一内部节点NS1及操作电压VDD之间的电性连接，使第一感测电容C S1的第一端被充电至操作电压VDD。第四切换电路SW4可截止第一内部节点NS1及接地端GND之间的电性连接。
第五切换电路SW5可截止第三输入端P3与第二内部节点NS2之间的电性连接，并可导通第三输入端P3与接地端GND之间的电性连接。第六切换电路SW6可导通第四输入端P4与第二内部节点NS2之间的电性连接，并可截止第四输入端P4与接地端GND之间的电性连接。第七切换电路SW7可导通第二内部节点NS2及操作电压VDD之间的电性连接，使第二感测电容C S2的第二端被充电至操作电压VDD。第八切换电路SW8可截止第二内部节点NS2及接地端GND之间的电性连接。
此外，在第一时段TP1中，第十一切换电路SW11可导通第三电容C3的第一端与接地端GND之间的电性连接。第十二切换电路SW12可截止第三电容C3的第一端与操作电压VDD之间的电性连接。第十三切换电路SW13可截止第三电容C3的第二端与接地端GND之间的电性连接，并可导通第三电容C3的第二端与操作电压VDD之间的电性连接，使第三电容C3的第二端被充电至操作电压VDD。第十四切换电路SW14可截止第三电容C3的第一端与第一内部节点NS1之间的电性连接。
第十五切换电路SW15可导通第四电容C4的第一端与接地端GND之间的电性连接。第十六切换电路SW16可截止第四电容C4的第一端与操作电压VDD之间的电性连接。第十七切换电路SW17可截止第四电容C4的第二端与接地端GND之间的电性连接，并可导 通第四电容C4的第二端与操作电压VDD之间的电性连接，使第四电容C4的第二端被充电至操作电压VDD。第十八切换电路S18可截止第四电容C4的第一端与第二内部节点NS2之间的电性连接。
此外，在第一时段TP1中，第九切换电路SW9可截止差分放大器112的第一输入端及第一内部节点NS1之间的电性连接，而第十切换电路SW10可截止差分放大器112的第一输入端及第二内部节点NS2之间的电性连接。
接着，在第一时段TP1之后的第二时段TP2中，第三切换电路SW3可截止第一内部节点NS1及操作电压VDD之间的电性连接，第十一切换电路SW11可截止第三电容C3的第一端与接地端GND之间的电性连接。此外，第十四切换电路SW14可导通第三电容C3的第一端与第一内部节点NS1之间的电性连接，而第十三切换电路SW13可导通第三电容C3的第二端与接地端GND之间的电性连接，并可截止第三电容C3的第二端与操作电压VDD之间的电性连接。此时第一感测电容C S1的第一端与第三电容C3的第一端都会耦接至第一内部节点NS1，因此第一感测电容C S1及第三电容C3中的电荷会进行重新分配，而第一内部节点NS1的电压VX 1可如式(1)表示。
Figure PCTCN2021073214-appb-000001
在第一感测电容C S1与第三电容C3相匹配的情况下，例如当第三电容C3的电容值为第一感测电容的固有电容值C S1的三分之一时，第一内部节点NS1的电压VX 1将与第一感测电容C S1的固有电容值与第三电容C3的电容值无关，而式(1)将可改写为式(2)。
Figure PCTCN2021073214-appb-000002
也就是说，第一内部节点NS1的电压VX 1实质上可相等于1/2倍的操作电压VDD。相似地，在第二时段TP2中，第七切换电路SW7可截止第二内部节点NS2及操作电压VDD之间的电性连接，第十五切换电路SW15可截止第四电容C4的第一端与接地端GND之间的电性连接，第十八切换电路SW18可导通第四电容C4的第一端与第二内部节点NS2之间的电性连接，而第十七切换电路SW17可导通第四电容C4的第二端与接地端GND之间的电性连接，并可截止第四电容C4的第二端与操作电压VDD之间的电性连接。此时第二感测电容C S2的第一端与第四电容C4的第一端都会耦接至第二内部节点NS2，因此第二感测电容C S2及第四电容C4中的电荷会进行重新分配，而在第二感测电容C S2与第四电容C4相匹配的情况下，例如当第四电容C4的电容值为第二感测电容C S2的固有电容值的三分之一时，第二内部节点NS2的电压VX 2将与第二感测电容C S2的固有电容值及第四电容C4的电容值无关，此时则电压VX 2可通过式(3)表示。
Figure PCTCN2021073214-appb-000003
在有些实施例中，由于检测电路100及机壳可能分别是由不同的厂商制作或设计，因此在制作检测电路100时，可能尚无法得知机壳的自容值，也就无法预知第一感测电容C S1及第二感测电容C S2的固有电容值大小为何。在此情况下，第三电容C3可包括可变电容或电容阵列，如此一来，当使用者在得知第一感测电容C S1的固有电容值 大小之后，就可以依据第一感测电容C S1的电容值，并通过控制信号来设定可变电容或电容阵列的电容值，以使第三电容C3能够与第一感测电容C S1相匹配。相似地，第四电容C4可包括可变电容或电容阵列，而当使用者在得知第二感测电容C S2的固有电容值大小之后，就可以依据第二感测电容C S2的固有电容值，并通过控制信号来设定可变电容或电容阵列的电容值，以使第四电容C4能够与第二感测电容C S2相匹配。
此外，在图4中，第七控制信号K7是在第三控制信号K3由高电位变为低电位之后才自低电位变为高电位，而第五控制信号K5是在第七控制信号K7由低电位变为高电位之后才自高电位变为低电位，以确保第一感测电容C S1、第二感测电容C S2、第三电容C3及第四电容C4中的电荷不会在进行重新分配时转移至外部或自外部转移。然而本申请并不以此为限，在有些实施例中，当第三控制信号K3由高电位变为低电位时，第七控制信号K7可同时自低电位变为高电位，而当第七控制信号K7自低电位变为高电位时，第五控制信号K5也可同时自高电位变为低电位。此外，在有些实施例中，第五控制信号K5及第六控制信号K6可以是互补的控制信号，因此第五控制信号K5及第六控制信号K6也会同步变换电位。
在第二时段TP2之后的第三时段TP3中，第九切换电路SW9可导通差分放大器112的第一输入端及第一内部节点NS1之间的电性连接，以通过第一电容C1进行积分，而第十切换电路SW10可导通差分放大器112的第一输入端及第二内部节点NS2之间的电性连接，以通过第二电容C2进行积分。在第三时段TP3中，第八控制信号K8处在高电位的时间长短会与第一电容C1及第二电容C2所需的积分时间有关，举例来说，第八控制信号K8处在高电位的时间长度可以设定为大于或等于足以让第一电容C1及第二电容C2完成积分，且足以使差分放大器112的第一输出端的电压VPO及第二输出端的电压VNO趋于稳定的时间长度。
在理想的情况下，也就是在没有温度变化也没有人体接近的情况 下，第一感测电容C S1与第三电容C3对于第一内部节点NS1的电压VX 1的影响可以互相抵消，因此第一内部节点NS1的电压VX 1将等于1/2倍的VDD，而与第一感测电容C S1的固有电容值及第三电容C3的电容值大小无关。同理，第二感测电容C S2与第四电容C4对于第二内部节点NS2的电压VX 2的影响也可以互相抵消，因此第二内部节点NS2的电压VX 2也会等于1/2倍的VDD，此时第一电容C1及第二电容C2不会有电荷转移。
由于检测电压信号VOUT主要是用来呈现人体接近时对第一感测电容C S1及第二感测电容C S2的感测电容值所造成的变化，因此若第一内部节点NS1的电压VX 1及第二内部节点NS2的电压VX 2与第一感测电容C S1及第二感测电容C S2的固有电容值以及第三电容C3及第四电容C4的电容值无关，将使得后续产生的检测电压信号VOUT不会因为第一感测电容C S1、第二感测电容C S2、第三电容C3及第四电容C4的大小而产生变化，而能够更加单纯而精准地呈现出人体接近时对第一感测电容C S1及第二感测电容C S2的感测电容值所造成的变化。
然而，在有温度变化而导致电容值产生变化及/或有人体接近的情况下，温度所导致的电容变化值ΔC T1及人体的等效电容C B会使得第一输入端P1及第二输入端P2之间所感测到的感测电容值产生变化，此时第一内部节点NS1的电压VX 1也会随之变动，导致有部分电荷移入或移出第一电容C1，其中转移的电荷量ΔQA1可如式(4)表示。
Figure PCTCN2021073214-appb-000004
相似地，温度所导致的电容变化值ΔC T2也会使得第三输入端P3及第四输入端P4之间的感测电容值产生变化，此时第二内部节点NS2的电压VX 2也会随之变动，然而，在第一阶段ST1中，第三输 入端P3会保持耦接至接地端GND，由于人体一般是处在接地状态，因此当人体接近第二感测电容C S2时，耦接至第二感测电容C S2的第一端的人体等效电容C B的两端都会接地，而不会对第三输入端P3及第四输入端P4之间的感测电容值造成影响，此时第二电容C2的转移电荷量ΔQA2可如式(5)表示。
Figure PCTCN2021073214-appb-000005
由于第一电容C1及第二电容C2是分别设置在差分放大器112的正输入端及负输入端，因此转移电荷量ΔQA1及ΔQA2会使差分放大器112的输出电压产生相反的变化，也就是说，在第一感测电容C S1与第二感测电容C S2的固有电容值相同的情况下，第一感测电容C S1及第三电容C3因为温漂而导致的电容变化值ΔC T1将会与第二感测电容C S2及第四电容C4因为温度而导致的电容变化值ΔC T2互相抵消，因此差分积分电路110在第一阶段中输出的电压将只会与人体等效电容C B所造成的影响有关，而与温度造成的电容变化无关。举例来说，在第一电容C1与第二电容C2具有相同电容值的情况下，检测电路100在第一阶段中所输出的检测电压信号VOUT则可如式(6)所示。
Figure PCTCN2021073214-appb-000006
在第二阶段ST2的第四时段TP4中，第一切换电路SW1可截止第一输入端P1与第一内部节点NS1之间的电性连接，并可导通第一输入端P1与接地端GND之间的电性连接，而第二切换电路SW2可导 通第二输入端P2与第一内部节点NS1之间的电性连接，并可截止第二输入端P2与接地端GND之间的电性连接。此外，第三切换电路SW3可截止第一内部节点NS1及操作电压VDD之间的电性连接，而第四切换电路SW4可导通第一内部节点NS1及接地端GND之间的电性连接，使第一感测电容C S1被放电至接地端GND。
第五切换电路SW5可导通第三输入端P3与第二内部节点NS2之间的电性连接，并可截止第三输入端P3与接地端GND之间的电性连接。第六切换电路SW6可截止第四输入端P4与第二内部节点NS2之间的电性连接，并可导通第四输入端P4与接地端GND之间的电性连接。第七切换电路SW7可截止第二内部节点NS2及操作电压VDD之间的电性连接，而第八切换电路SW8可导通第二内部节点NS2及接地端GND之间的电性连接，使第二感测电容C S2被放电至接地端GND。
第十一切换电路SW11可截止第三电容C3的第一端与接地端GND之间的电性连接，而第十二切换电路SW12可导通第三电容C3的第一端与操作电压VDD之间的电性连接，使第三电容C3被充电至操作电压VDD。第十三切换电路SW13可导通第三电容C3的第二端与接地端GND之间的电性连接，并可截止第三电容C3的第二端与操作电压VDD之间的电性连接，而第十四切换电路SW14可截止第三电容C3的第一端与第一内部节点NS1之间的电性连接。
第十五切换电路SW15可截止第四电容C4的第一端与接地端GND之间的电性连接，第十六切换电路SW16可导通第四电容C4的第一端与操作电压VDD之间的电性连接，使第四电容C4被充电至操作电压VDD。第十七切换电路SW17可导通第四电容C4的第二端与接地端GND之间的电性连接，并可截止第四电容C4的第二端与操作电压VDD之间的电性连接，而第十八切换电路SW18可截止第四电容C4的第一端与第二内部节点NS2之间的电性连接。
此外，在第四时段TP4中，第九切换电路SW9可截止差分放大器112的第一输入端及第一内部节点NS1之间的电性连接，而第十切换电路SW10可截止差分放大器112的第一输入端及第二内部节点NS2 之间的电性连接。
接着，在第四时段TP4之后的第五时段TP5中，第四切换电路SW4可截止第一内部节点NS1及接地端GND之间的电性连接，第八切换电路SW8可截止第二内部节点NS2及接地端GND之间的电性连接，第十二切换电路SW12可截止第三电容C3的第一端与操作电压VDD之间的电性连接，而第十六切换电路SW16可截止第四电容C4的第一端与操作电压VDD之间的电性连接。第十四切换电路SW14可导通第三电容C3的第一端与第一内部节点NS1之间的电性连接，使第一感测电容C S1与第三电容C3中的电荷重新分配，而第十八切换电路SW18可导通第四电容C4的第一端与第二内部节点NS2之间的电性连接，使第二感测电容C S2与第四电容C4中的电荷重新分配。第十三切换电路SW13可截止第三电容C3的第二端与接地端GND之间的电性连接，并可导通第三电容C3的第二端与操作电压VDD之间的电性连接。第十七切换电路SW17可截止第四电容C4的第二端与接地端之间的电性连接，并可导通第四电容C4的第二端与操作电压VDD之间的电性连接。此时，由于第三电容C3的第二端会被抬升至操作电压VDD，因此第三电容C3的第一端的电压也会随之被抬升至两倍的操作电压2VDD，而在第一感测电容C S1与第三电容C3中的电荷完成重新分配之后，第一内部节点NS1的电压VX 1可如式(7)表示。
Figure PCTCN2021073214-appb-000007
在第一感测电容C S1与第三电容C3相匹配的情况下，例如当第三电容C3的电容值为第一感测电容C S1的固有电容值的三分之一时，则式(7)将可改写为式(8)。
Figure PCTCN2021073214-appb-000008
相似地，在第二感测电容C S2与第四电容C4相匹配的情况下，例如当第四电容C4的电容值为第二感测电容C S2的固有电容值的三分之一时，第二内部节点NS2的电压VX 2可由式(9)表示。
Figure PCTCN2021073214-appb-000009
在图4的第五时段TP5中，第七控制信号K7是在第四控制信号K4由高电位变为低电位之后才自低电位变为高电位，以确保第一感测电容C S1、第二感测电容C S2、第三电容C3及第四电容C4中的电荷不会在进行重新分配时转移至外部或自外部转移。然而在有些实施例中，当第四控制信号K4由高电位变为低电位时，第七控制信号K7也可同时自低电位变为高电位。此外，第五控制信号K5可在第七控制信号K7由低电位变为高电位之后才自低电位变为高电位，以确保在重新分配电荷的过程中，第三电容C3的第二端及第四电容C4的第二端的电位能够进一步抬升。
在第五时段TP5之后的第六时段TP6中，第九切换电路SW9可导通差分放大器112的第一输入端及第一内部节点NS1之间的电性连接，以通过第一电容C1进行积分，而第十切换电路SW10可导通差分放大器112的第二输入端及第二内部节点NS2之间的电性连接，以通过第二电容C2进行积分，此时差分放大器112的第一输出端及第二输出端也可输出检测电压信号VOUT。
依据式(8)及式(9)可以看出，在理想的情况下，第一感测电容C S1本身的固有电容值与第三电容C3的电容值对于第一内部节点NS1的电压VX 1的影响可以互相抵消，且第二感测电容C S2本身的固有电容值与第四电容C4的电容值对于第二内部节点NS2的电压VX 2的影响也可以互相抵消，因此第一内部节点NS1的电压VX 1与第二内部节点NS2的电压VX 2都会等于1/2倍的VDD，此时在第一电容C1及第二电容C2中将不会有电荷转移。
然而，当有温度变化时，第一感测电容C S1及第三电容C3因为温度而产生的电容变化值ΔC T1仍会使得第一输入端P1及第二输入端P2之间的感测电容值产生变化，此时第一内部节点NS1的电压VX 1也会随之变动，导致有部分电荷移入或移出第一电容C1。此外，由于在第二阶段ST2中，第一输入端P1会持续地被耦接至接地端GND，因此即使在有人体接近第一感测电容C S1时，耦接至第一感测电容C S1的第一端的人体等效电容C B的两端都会处于接地状态，而不会对感测电容值造成影响，此时转移的电荷量ΔQB1可如式(10)表示。
Figure PCTCN2021073214-appb-000010
相对地，由于在第五时段TP5中，第八切换电路SW8会截止第三输入端P3与接地端GND之间的电性连接，因此当有人体接近到第二感测电容C S2时，人体的等效电容C B将会通过第二感测电容C S2的第一端与第二感测电容C S2并联，而对第三输入端P3及第四输入端P4之间的感测电容值造成影响。此外，当有温度变化时，第二感测电容C S2及第四电容C4因为温度而产生的电容变化值ΔC T2也会使得第三输入端P3及第四输入端P4之间的感测电容值产生变化，使得第二内部节点NS2的电压VX 2随之变动，导致有部分电荷移入或移出第二电容C2，其中转移的电荷量ΔQB2可如式(11)表示。
Figure PCTCN2021073214-appb-000011
在式(10)及式(11)中，由于因为温度造成感测电容值变化所造成的影响是以共模噪声的方式存在，因此不会影响到差分放大器112的输出电压，使得在第二阶段ST2中检测电压信号VOUT的变化只与所检测到的人体等效电容C B有关。也就是说，在第一阶段ST1中，检测电路100是通过第一感测电容C S1来检测人体等效电容C B对第一输入端P1及第二输入端P2之间的电容值的影响，而在第二阶段ST2中，检测电路100则是通过第二感测电容C S2来检测人体等效电容C B对第三输入端P3及第四输入端P4之间的电容值的影响，因此在检测操作的第一阶段ST1及第二阶段ST2完成后，检测电压信号VOUT就能够包含通过第一感测电容C S1及第二感测电容C S2所检测到的人体等效电容C B变化，从而完整地呈现出人体等效电容C B的影响，并确保触碰检测的准确度。
再者，第一感测电容C S1及第二感测电容C S2之间虽然可能会产生互容C m，然而在检测操作的第一阶段ST1中，第一内部节点NS1及第二内部节点NS2同样会被充电至操作电压VDD，而在第二阶段ST2中，第一内部节点NS1及第二内部节点NS2则同样会被放电至接地端GND，因此在检测操作的过程中，互容C m的两端会保持在几乎相同的电压，而不会储存电荷。如此一来，就可以减少互容C m对检测电压信号VOUT的影响，而在依据检测电压信号VOUT进行碰触检测时也可以得到更加准确的结果。
此外，在图3中，差分积分电路110还可包括第一重置切换开关RSW1及第二重置切换开关RSW2。第一重置切换开关RSW1可耦接于差分放大器112的第一输入端及差分放大器112的第一输出端，第一重置切换开关RSW1可以在重置操作中，导通差分放大器112的第 一输入端及差分放大器112的第一输出端之间的电性连接，以对第一电容C1进行放电重置。第二重置切换开关RSW2可耦接于差分放大器112的第二输入端及差分放大器112的第二输出端，第二重置切换开关RSW2可以在重置操作中，导通差分放大器112的第二输入端及差分放大器112的第二输出端之间的电性连接，以对第二电容C2进行放电重置。
此外，在检测操作中，第一重置切换开关RSW1可截止差分放大器112的第一输入端及差分放大器112的第一输出端之间的电性连接，而第二重置切换开关RSW2可截止差分放大器112的第二输入端及差分放大器112的第二输出端之间的电性连接，以使差分积分电路110能够通过第一电容C1及第二电容C2进行积分。
由于第一重置切换开关RSW1及第二重置切换开关RSW2可以使第一电容C1及第二电容C2进行放电重置，使得差分积分电路110在进行积分时，不会受到前次检测操作的影响，从而可以提升检测电路100的准确性及稳定性。
在图3的实施例中，检测电路100是通过第三电容C3及第四电容C4来去除第一感测电容C S1及第二感测电容C S2的固有电容值对检测电压信号VOUT所造成的影响，以及去除因为温度导致第一感测电容C S1及第二感测电容C S2的感测电容值变化所造成的误差。在有些实施例中，第三电容C3及第四电容C4也可改以设置在外部的感测电容来代替，以节省检测电路所需的面积。
图5是本申请另一实施例的检测电路200的示意图，检测电路200与检测电路100具有相似的结构，并可根据相似的原理操作。然而，检测电路200还可包含第五输入端P5、第六输入端P6、第七输入端P7、第八输入端P8、第十九切换电路SW19、第二十切换电路SW20、第二十一切换电路SW21、第二十二切换电路SW22、第二十三切换电路SW23、第二十四切换电路SW24、第二十五切换电路SW25、第二十六切换电路SW26、第二十七切换电路SW27及第二十八切换电路SW28。
在图5中，第五输入端P5可耦接于第三感测电容C S3的第一端， 第六输入端P6可耦接于第三感测电容C S3的第二端，第七输入端P7可耦接于第四感测电容C S4的第一端，而第八输入端P8可耦接于第四感测电容C S4的第二端。第一感测电容C S1、第二感测电容C S2、第三感测电容C S3及第四感测电容C S4本身虽具有固定的电容值，然而当有人体接近或有温度变化时，检测电路200所感测到的第一感测电容C S1、第二感测电容C S2、第三感测电容C S3及第四感测电容C S4的感测电容值将会有所变化，因此检测电路200可通过第一感测电容C S1、第二感测电容C S2、第三感测电容C S3及第四感测电容C S4进行电容变化的检测以输出对应的检测电压信号VOUT。
在本实施例中，第三感测电容C S3及第四感测电容C S4与第一感测电容C S1及第二感测电容C S2相似，可以是包覆检测电路200的电子装置20的机壳的至少一部分所形成的自容。举例来说，第三感测电容C S3的第一端及第四感测电容C S4的第一端可以位于机壳的至少一部分的外侧，而第三感测电容C S3的第二端及第四感测电容C S4的第二端可以位于机壳的至少一部分的内侧。如此一来，当人体接近至机壳时，人体的等效电容C B将与第一感测电容C S1的第一端、第二感测电容C S2的第一端、第三感测电容C S3的第一端及第四感测电容C S4的第一端相耦接，使第一感测电容C S1、第二感测电容C S2、第三感测电容C S3及第四感测电容C S4的感测电容值产生变化。
图7是本申请一实施例中，第一感测电容C S1、第二感测电容C S2、第三感测电容C S3及第四感测电容C S4的设置关系图。在图7中，第一感测电容C S1及第二感测电容C S2是相邻设置，第二感测电容C S2及第三感测电容C S3是相邻设置，且第三感测电容C S3及第四感测电容C S4是相邻设置，因此第一感测电容C S1及第二感测电容C S2之间会产生互容C m1，第二感测电容C S2及第三感测电容C S3之间会产生互容C m2，第三感测电容C S3及第四感测电容C S4之间会产生互容C m3。
由于检测电路200可以利用外部机壳的自容作为第三感测电容C S3及第四感测电容C S4以抵消第一感测电容C S1及第二感测电容C S2本身固有电容值对检测电压信号VOUT所造成的影响、抵消温度对第一感测电容C S1及第二感测电容C S2的感测电容值所造成的变化，并 且可以消除第一互容C m1、第二互容C m2及第三互容C m3对检测电压信号VOUT所造成的影响，因此可以取代检测电路100中的第三电容C3及第四电容C4，从而减少检测电路200所需的电路面积。
在图5中，第十九切换电路SW19可耦接于第一内部节点NS1及差分积分电路210的第一输入端NI1，第十九切换电路SW19可以导通或截止第一内部节点NS1及差分积分电路210的第一输入端NI1之间的电性连接。第二十切换电路SW20可耦接于第二内部节点NS2及差分积分电路210的第二输入端NI2，第二十切换电路SW20可导通或截止第二内部节点NS2及差分积分电路210的第二输入端NI2之间的电性连接。如此一来，在检测电路200执行检测操作时，差分积分电路210便可通过第十九切换电路SW19及第二十切换电路SW20耦接至第一内部节点NS1及第二内部节点NS2，并根据第一内部节点NS1及第二内部节点NS2的电压进行积分以产生检测电压信号VOUT。
第二十一切换电路SW21可导通或截止差分积分电路210的第一输入端NI1及接地端GND之间的电性连接。第二十二切换电路SW22可导通或截止差分积分电路210的第一输入端NI1及操作电压VDD之间的电性连接。第二十三切换电路SW23可导通或截止第五输入端P5与接地端GND之间的电性连接，并可导通或截止第五输入端P5与差分积分电路210的第一输入端NI1之间的电性连接。第二十四切换电路SW24可导通或截止第六输入端P6与接地端GND之间的电性连接，并可导通或截止第六输入端P6与差分积分电路210的第一输入端NI1之间的电性连接。
第二十五切换电路SW25可导通或截止差分积分电路210的第二输入端NI2及操作电压VDD之间的电性连接。第二十六切换电路SW26可导通或截止差分积分电路210的第二输入端NI2及接地端GND之间的电性连接。第二十七切换电路SW27可导通或截止第七输入端P7与接地端GND之间的电性连接，并可导通或截止第七输入端P7与差分积分电路210的第二输入端NI2之间的电性连接。第二十八切换电路SW28可导通或截止第八输入端P8与接地端GND之间 的电性连接，并可导通或截止第八输入端P8与差分积分电路210的第二输入端NI2之间的电性连接。
在本实施例中，第二十三切换电路SW23包括第十三开关S13及第十四开关S14。第十三开关S13具有第一端、第二端及控制端，第十三开关S13的第一端耦接于第五输入端P5，第十三开关S13的第二端耦接于差分积分电路210的第一输入端NI1。第十四开关S14具有第一端、第二端及控制端，第十四开关S14的第一端耦接于第五输入端P5，第十四开关S14的第二端耦接于接地端GND。
第二十四切换电路SW24包括第十五开关S15及第十六开关S16，第十五开关S15具有第一端、第二端及控制端，第十五开关S15的第一端耦接于第六输入端P6，第十五开关S15的第二端耦接于差分积分电路210的第一输入端NI1。第十六开关S16具有第一端、第二端及控制端，第十六开关S16的第一端耦接于第六输入端P6，第十六开关S16的第二端耦接于接地端GND。
第二十七切换电路SW27包括第十七开关S17及第十八开关S18。第十七开关S17具有第一端、第二端及控制端，第十七开关S17的第一端耦接于第七输入端P7，第十七开关S17的第二端耦接于差分积分电路210的第二输入端NI2。第十八开关S18具有第一端、第二端及控制端，第十八开关S18的第一端耦接于第七输入端P7，第十八开关S18的第二端耦接于接地端GND。
第二十八切换电路SW28包括第十九开关S19及第二时开关S20，第十九开关S19具有第一端、第二端及控制端，第十九开关S19的第一端耦接于第八输入端P8，第十九开关S19的第二端耦接于差分积分电路210的第二输入端NI2。第二十开关S20具有第一端、第二端及控制端，第二十开关S20的第一端耦接于第八输入端P8，第二十开关S20的第二端耦接于接地端GND。
此外，第二十一切换电路SW21、第二十二切换电路SW22、第二十五切换电路SW25及第二十六切换电路SW26可由单一开关来实作。
在图5中，第一切换电路SW1、第二切换电路SW2、第五切换电路SW5、第六切换电路SW6、第二十三切换电路SW23、第二十四切换电路SW24、第二十七切换电路SW27及第二十八切换电路SW28可根据第一控制信号K1及第二控制信号K2来导通或截止对应的电性连接，第三切换电路SW3、第七切换电路SW7、第二十一切换电路SW21及第二十五切换电路SW25可根据第三控制信号K3来导通或截止对应的电性连接。第四切换电路SW4、第八切换电路SW8、第二十二切换电路SW22及第二十六切换电路SW26可根据第四控制信号K4来导通或截止对应的电性连接。第十九切换电路SW19及第二十切换电路SW20可根据第九控制信号K9来导通或截止对应的电性连接，而第九切换电路SW9及第十切换电路SW10可根据第八控制信号K8来导通或截止对应的电性连接。
图6是检测电路200在执行检测操作时所接收到的信号时序图。在本实施例中，当控制信号K1处于高电位时，第一切换电路SW1会导通第一输入端P1与第一内部节点NS1之间的电性连接，第二切换电路SW2会导通第二输入端P2与接地端GND之间的电性连接，第五切换电路SW5会导通第三输入端P3与第一内部节点NS1之间的电性连接，第六切换电路SW6会导通第四输入端P4与接地端GND之间的电性连接，第二十三切换电路SW23会导通第五输入端P5与接地端GND之间的电性连接，第二十四切换电路SW24会导通第六输入端P6与差分积分电路210的第一输入端NI1之间的电性连接，第二十七切换电路SW27会导通第七输入端P7与接地端GND之间的电性连接，第二十八切换电路SW28会导通第八输入端P8与差分积分电路210的第二输入端NI2之间的电性连接。
当控制信号K2处于高电位时，第一切换电路SW1会导通第一输入端P1与接地端GND之间的电性连接，第二切换电路SW2会导通第二输入端P2与第一内部节点NS1之间的电性连接，第五切换电路SW5会导通第三输入端P3与接地端GND的电性连接，第六切换电路SW6会导通第四输入端P4与第一内部节点NS1之间的电性连接，第二十三切换电路SW23会导通第五输入端P5与差分积分电路210 的第一输入端NI1之间的电性连接，第二十四切换电路SW24会导通第六输入端P6与接地端GND之间的电性连接，第二十七切换电路SW27会导通第七输入端P7与差分积分电路210的第二输入端NI2之间的电性连接，第二十八切换电路SW28会导通第八输入端P8与接地端GND之间的电性连接。
此外，切换电路SW3、SW4、SW7、SW8、SW21、SW22、SW25、SW26、SW19、SW20、SW9及SW10会在控制信号K3、K4、K8及K9中对应的控制信号处于高电位时，导通对应的电性连接，并在控制信号K3、K4、K8及K9中对应的控制信号处于低电位时，截止对应的电性连接。
在图6中，检测操作可包含第一阶段ST1及第二阶段ST2，第一阶段ST1可包含第一时段TP1、第二时段TP2及第三时段TP3，而第二阶段ST2可包含第四时段TP4、第五时段TP5及第六时段TP6。
在第一阶段ST1中，检测电路200可将第一感测电容C S1充电至操作电压VDD，并使第三感测电容C S3放电至接地端GND，再使得第一感测电容C S1及第三感测电容C S3的内部电荷进行重新分配。此外，由于第五输入端P5是耦接至第三感测电容C S3的第一端并且会持续地耦接至接地端GND，因此第三感测电容C S3的第一端，也就是第三感测电容C S3的外侧极板会处于接地状态。由于人体一般是处于接地状态，因此当人体接近第三感测电容C S3时，耦接至第三感测电容C S3的第一端的人体等效电容C B的两端都将处于接地状态，而不会造成第三感测电容C S3的感测电容值的变化。因此，在第一感测电容C S1与第三感测电容C S3相匹配的情况下，第一内部节点NS1的电压将只会与人体接近第一输入端P1时与第一感测电容C S1并联的人体等效电容C B变化有关。关于第一感测电容C S1与第三感测电容C S3相匹配的条件及操作细节将说明于后。
此外，在第一阶段ST1中，检测电路200可将第二感测电容C S2放电至接地端GND，并使第四感测电容C S4充电至操作电压VDD，再使得第二感测电容C S2及第四感测电容C S4的内部电荷进行重新分 配。此外，由于第七输入端P7是耦接至第四感测电容C S4的第一端，且会持续地耦接至接地端GND，因此第四感测电容C S4的第一端，也就是第四感测电容C S4的外侧极板会处于接地状态。在此情况下，当人体接近第四感测电容C S4时，耦接至第四感测电容C S4的第一端的人体等效电容C B的两端都将处于接地状态，而不会造成第四感测电容C S4的感测电容值的变化。此时，若第二感测电容C S2与第四感测电容C S4相匹配，则第二内部节点NS2的电压将只会与人体接近第三输入端P3时与第二感测电容C S2并联的人体等效电容C B变化有关。关于第二感测电容C S2与第四感测电容C S4相匹配的条件及操作细节将说明于后。
再者，由于差分积分器210会根据第一内部节点NS1及第二内部节点NS2的电压，分别通过第一电容C1及第二电容C2进行积分，因此第一内部节点NS1及第二内部节点NS2的电压会使检测电压信号VOUT产生相反的变化，使得在第一阶段ST1结束后，检测电压信号VOUT的变化会与人体等效电容造成第一感测电容C S1及第二感测电容C S2的感测电容值变化有关。
在第二阶段ST2中，检测电路200可将第一感测电容C S1放电至接地端GND，并使第三感测电容C S3充电至操作电压VDD，再使第一感测电容C S1及第三感测电容C S3的内部电荷进行重新分配。在第二阶段ST2中，由于第一输入端P1是耦接至第一感测电容C S1的第一端并会持续地耦接至接地端GND，因此若第一感测电容C S1与第三感测电容C S3相匹配，则第一内部节点NS1的电压将只会与人体接近第三感测电容C S3时与第三感测电容C S3并联的人体等效电容C B变化有关。
此外，在第二阶段ST2中，检测电路200可将第二感测电容C S2充电至操作电压VDD，并使第四感测电容C S4放电至接地端GND，再使第二感测电容C S2及第四感测电容C S4的内部电荷进行重新分配。在第二阶段ST2中，由于第三输入端P3是耦接至第二感测电容C S2的第一端并会持续地耦接至接地端GND，因此若第二感测电容C S2 与第四感测电容C S4相匹配，则第二内部节点NS2的电压将只会与人体接近第四感测电容C S4时与第四感测电容C S4并联的人体等效电容C B有关。
再者，由于差分积分器210会根据第一内部节点NS1及第二内部节点NS2的电压，分别通过第一电容C1及第二电容C2进行积分，因此第一内部节点NS1及第二内部节点NS2的电压会使检测电压信号VOUT产生相反的变化，使得在第二阶段ST2结束后，检测电压信号VOUT的变化会与人体等效电容C B造成第三感测电容C S3及第四感测电容C S4的感测电容值的变化有关。
也就是说，在第一阶段ST1中，检测电路200可以通过第一感测电容C S1及第二感测电容C S2检测到人体等效电容所造成的影响，而在第二阶段ST2中，检测电路200可通过第三感测电容C S3及第四感测电容C S4检测到人体等效电容所造成的影响。如此一来，在第一阶段ST1及第二阶段ST2结束后，检测电路200所输出的检测电压信号VOUT将完整地呈现出人体等效电容C B对第一感测电容C S1、第二感测电容C S2、第三感测电容C S3及第四感测电容C S4的感测电容值所造成的变化，从而提升依据检测电压信号VOUT进行触碰检测时的准确度。
然而，在第一阶段ST1及第二阶段ST2中，由于第二感测电容C S2与第三感测电容C S3之间的互容C m2的两端会处于相同电压，因此不会储存电荷，而不会对检测电路200的检测结果造成影响。此外，第一感测电容C S1及第二感测电容C S2之间的互容C m1及第三感测电容C S3及第四感测电容C S4之间的互容C m3会处在相反的充电状态，因此互容C m1及C m3所造成的影响会在差分积分的过程中互相抵消，因此也不会对检测电路200所输出的检测电压信号VOUT造成影响。
在检测电路200中，第一感测电容C S1及第三感测电容C S3因为温度导致感测电容值变化以及自身固定电容对检测电压信号VOUT的影响可以互相抵消，且第二感测电容C S2及第四感测电容C S4因为温度导致感测电容值变化以及自身固定电容对检测电压信号VOUT的 影响可以互相抵消，因此在输出检测电压信号VOUT时，检测电路200已经自动消除了第一感测电容C S1、第二感测电容C S2、第三感测电容C S3及第四感测电容C S4本身的固有电容以及因为温度导致感测电容值变化的误差。如此一来，在后续使用模拟数字转换电路进行数值的判读时，就可以不需预留空间给温度对检测电压信号VOUT所造成的影响，换句话说，模拟数字转换电路的整个输入范围都可以有效地用来判读人体等效电容所造成的变化，从而增加可有效判读数值的范围，即达到提高有效感测范围的目的。
在图6的第一时段TP1中，第一切换电路SW1、第二切换电路SW2、第三切换电路SW3及第四切换电路SW4可使第一感测电容C S1被充电至操作电压VDD。第五切换电路SW5、第六切换电路SW6、第七切换电路SW7及第八切换电路SW8可使第二感测电容C S2被放电至接地端GND。
第二十一切换电路SW21、第二十二切换电路SW22、第二十三切换电路SW23及第二十四切换电路SW24可使第三感测电容C S3将被放电至接地端GND。第二十五切换电路SW25、第二十六切换电路SW26、第二十七切换电路S27及第二十八切换电路SW28可使第四感测电容C S4被充电至操作电压VDD。
此外，第十九切换电路SW19可截止第一内部节点NS1及差分积分电路210的第一输入端NI1之间的电性连接，而第二十切换电路SW20可截止第二内部节点NS2及差分积分电路210的第二输入端NI2之间的电性连接。第九切换电路SW9可截止差分放大器212的第一输入端及差分积分电路210的第一输入端NI1之间的电性连接，而第十切换电路SW10可截止差分放大器212的第二输入端及差分积分电路210的第二输入端NI2之间的电性连接。
接着，在第一时段TP1之后的第二时段TP2中，第三切换电路SW3可截止第一内部节点NS1及操作电压VDD之间的电性连接，第二十一切换电路SW21可截止差分积分电路210的第一输入端NI1与接地端GND之间的电性连接。此外，第十九切换电路SW19可导通第一内部节点NS1及差分积分电路210的第一输入端NI1之间的电性连 接，使第一感测电容C S1与第三感测电容C S3中的电荷重新分配，而第一内部节点NS1的电压VX 1可如式(12)表示。
Figure PCTCN2021073214-appb-000012
在第一感测电容C S1与第三感测电容C S3相匹配的情况下，例如当第一感测电容C S1及第三感测电容C S3具有相同的固有电容值时，第一内部节点NS1的电压VX 1将与第一感测电容C S1与第三感测电容C S3的固有电容值无关，而式(12)将可改写为式(13)。
Figure PCTCN2021073214-appb-000013
也就是说，第一内部节点NS1的电压VX 1实质上可相等于1/2倍的操作电压VDD。相似地，在第二时段TP2中，第八切换电路SW8可截止第二内部节点NS2及接地端GND之间的电性连接，第二十五切换电路SW25可截止差分积分电路210的第二输入端NI2及操作电压VDD之间的电性连接，而第二十切换电路SW20可导通第二内部节点NS2及差分积分电路210的第一输入端NI1之间的电性连接，使第二感测电容C S2与第四感测电容C S4中的电荷重新分配。在第二感测电容C S2与第四感测电容C S4相匹配的情况下，第二内部节点NS2的电压VX 2将可与第二感测电容C S2与第四感测电容C S4的电容值无关。举例来说，若第二感测电容C S2及第四感测电容C S4具有相同的固有电容值，则电压VX 2可通过式(14)表示。
Figure PCTCN2021073214-appb-000014
在第二时段TP2之后的第三时段TP3中，第九切换电路SW9可导通差分放大器212的第一输入端及差分积分电路210的第一输入端NI1之间的电性连接，以通过第一电容C1进行积分，而第十切换电路SW10可导通差分放大器212的第二输入端及差分积分电路210的第二输入端NI2之间的电性连接，以通过第二电容C2进行积分。
根据式(12)可知，在第一感测电容C S1与第三感测电容C S3具有相同电容值的情况下，两者本身的固有电容值以及因为温度导致的感测电容值变化会互相抵消，因此在没有人体接近时，第一内部节点NS1的电压VX 1将等于1/2倍的VDD。同理，第二感测电容C S2与第四感测电容C S4本身的固有电容值以及因为温度导致的感测电容值也可以互相抵消，因此第二内部节点NS2的电压VX 2也会等于1/2倍的VDD，此时第一电容C1及第二电容C2不会有电荷转移。
然而，当有人体接近时，人体的等效电容C B会使得第一输入端P1及第二输入端P2之间的感测电容值产生变化，此时第一内部节点NS1的电压VX 1也会随之变动，导致有部分电荷移入或移出第一电容C1，而转移的电荷量ΔQA1可如式(15)表示。此外，由于在第一阶段ST1中，第五输入端P5会持续耦接至接地端GND，因此第三感测电容C S3的第一端也会耦接至接地端GND，使得耦接至第三感测电容C S3的第一端的人体等效电容C B的两端都处于接地状态，而不会影响到第五输入端P5及第六输入端P6之间的感测电容值。
Figure PCTCN2021073214-appb-000015
相似地，当有人体接近时，人体的等效电容C B会与第二感测电容C S2的第一端并联，使得第三输入端P3及第四输入端P4之间的感测电容值产生变化，此时第二内部节点NS2的电压VX 2也会随之变动，导致有部分电荷移入或移出第二电容C2，其中转移的电荷量ΔQA2可如式(16)表示。此外，由于在第一阶段ST1中，第七输入端P7会持续耦接至接地端GND，因此人体等效电容C B并不会影响到第七输入端P7及第八输入端P8之间的感测电容值。
Figure PCTCN2021073214-appb-000016
由于第一电容C1及第二电容C2是分别设置在差分放大器212的正输入端及负输入端，因此转移电荷量ΔQA1及ΔQA2会对差分放大器212的输出电压产生相反的变化，因此在第一电容C1及第二电容C2具有相同电容值的情况下，差分积分电路210所输出的检测电压信号VOUT可如式(17)所示。
Figure PCTCN2021073214-appb-000017
在第一阶段ST1的第一时段TP1中，第一内部节点NS1会处在操作电压VDD，而第二内部节点NS2会处在接地端GND。相对地，差分积分电路210的第一输入端NI1会处在接地端GND，而差分积分电路210的第二输入端NI2会处在操作电压VDD，因此互容C m1及C m3的充电方向相反，两者所造成的影响可互相抵消，因此不会影响到检测操作的进行。此外，互容C m2并未在图5中绘出，但由于互容C m2的两端都会耦接到接地端GND，因此不会储存电荷，也不会影响 到检测操作的进行。
在第一阶段ST1之后的第二阶段ST2的第四时段TP4中，第一切换电路SW1、第二切换电路SW2、第三切换电路SW3及第四切换电路SW4可使得第一感测电容C S1被放电至接地端GND。第五切换电路SW5、第六切换电路SW6、第七切换电路SW7及第八切换电路SW8可使得第二感测电容C S2被充电至操作电压VDD。
第二十一切换电路SW21、第二十二切换电路SW22、第二十三切换电路及第二十四切换电路SW24可使第三感测电容C S3被充电至操作电压VDD。
第二十五切换电路SW25、第二十六切换电路SW26、第二十七切换电路SW27及第二十八切换电路SW28可使第四感测电容C S4被放电至接地端。
此外，第十九切换电路SW19可截止第一内部节点NS1及差分积分电路210的第一输入端NI1之间的电性连接，第二十切换电路SW20可截止第二内部节点NS2及差分积分电路210的第二输入端NI2之间的电性连接，第九切换电路SW9可截止差分放大器212的第一输入端及差分积分电路210的第一输入端NI1之间的电性连接，而第十切换电路SW10可截止差分放大器212的第二输入端及差分积分电路210的第二输入端NI2之间的电性连接。
接着，在第四时段TP4之后的第五时段TP5中，第四切换电路SW4可截止第一内部节点NS1及接地端GND之间的电性连接，第二十二切换电路SW22可截止差分积分电路210的第一输入端NI1与操作电压VDD之间的电性连接，而第十九切换电路SW19可导通第一内部节点NS1及差分积分电路210的第一输入端NI1之间的电性连接，使第一感测电容C S1与第三感测电容C S3中的电荷重新分配，而第一内部节点NS1的电压VX 1可如式(18)表示。
Figure PCTCN2021073214-appb-000018
在第一感测电容C S1与第三感测电容C S3相匹配的情况下，例如当第一感测电容C S1及第三感测电容C S3具有相同的固有电容值时，第一内部节点NS1的电压VX 1将与第一感测电容C S1与第三感测电容C S3的固有电容值无关，而式(18)将可改写为式(19)。
Figure PCTCN2021073214-appb-000019
也就是说，第一内部节点NS1的电压VX 1实质上可相等于1/2倍的操作电压VDD。相似地，在第五时段TP5中，第七切换电路SW7可截止第二内部节点NS2及操作电压VDD之间的电性连接，第二十六切换电路SW26可截止差分积分电路210的第二输入端NI2及接地端GND之间的电性连接，而第二十切换电路SW20可导通第二内部节点NS2及差分积分电路210的第二输入端NI2之间的电性连接，使第二感测电容C S2与第四感测电容C S4中的电荷重新分配。在第二感测电容C S2与第四感测电容C S4相匹配的情况下，第二内部节点NS2的电压VX 2将可与第二感测电容C S2与第四感测电容C S4的电容值无关。举例来说，若第二感测电容C S2及第四感测电容C S4具有相同的固有电容值，则电压VX 2可通过式(20)表示。
Figure PCTCN2021073214-appb-000020
在第五时段TP5后的第六时段TP6中，第九切换电路SW9可导通差分放大器212的第一输入端及差分积分电路210的第一输入端 NI1之间的电性连接，以通过第一电容C1进行积分，第十切换电路SW10可导通差分放大器212的第二输入端及差分积分电路210的第二输入端NI2之间的电性连接，以通过第二电容C2进行积分，而差分放大器212的第一输出端及第二输出端可输出检测电压信号VOUT。
根据式(18)可知，在第一感测电容C S1与第三感测电容C S3具有相同电容值的情况下，两者的固有电容值以及因为温度导致的感测电容值变化会互相抵消，因此在没有人体接近时，第一内部节点NS1的电压VX 1将等于1/2倍的VDD。同理，第二感测电容C S2与第四感测电容C S4的固有电容值以及因为温度导致的感测电容值变化也可以互相抵消，因此第二内部节点NS2的电压VX 2也会等于1/2倍的VDD，此时第一电容C1及第二电容C2不会有电荷转移。
然而，当有人体接近时，人体的等效电容C B会与第三感测电容C S3并联，使得第五输入端P5及第六输入端P6之间的感测电容值产生变化，此时第一内部节点NS1的电压VX 1也会随之变动，导致有部分电荷移入或移出第一电容C1，而转移的电荷量ΔQA1可如式(21)表示。此外，由于在第二阶段ST2中，第一输入端P1会持续耦接至接地端GND，因此人体等效电容C B并不会影响到第一输入端P1及第二输入端P2之间的感测电容值。
Figure PCTCN2021073214-appb-000021
相似地，当有人体接近时，人体的等效电容C B会与第四感测电容C S4并联，使得第七输入端P7及第八输入端P8之间的感测电容值产生变化，此时第二内部节点NS2的电压VX 2也会随之变动，导致有部分电荷移入或移出第二电容C2，其中转移的电荷量ΔQA2可如式(22)表示。此外，由于在第二阶段ST2中，第三输入端P3会持续耦 接至接地端GND，因此人体等效电容C B并不会影响到第三输入端P3及第四输入端P4之间的感测电容值。
Figure PCTCN2021073214-appb-000022
由于第一电容C1及第二电容C2是分别设置在差分放大器212的正输入端及负输入端，因此转移电荷量ΔQA1及ΔQA2会对差分放大器212的输出电压造成反向的变化，而在第一电容C1及第二电容C2具有相同电容值的情况下，差分积分电路210所输出的检测电压信号VOUT可如式(23)所示。
Figure PCTCN2021073214-appb-000023
在第二阶段ST2的第一时段TP1中，第一内部节点NS1会处在接地端GND，而第二内部节点NS2会处在操作电压VDD。相对地，差分积分电路210的第一输入端NI1会处在操作电压VDD，而差分积分电路210的第二输入端NI2会处在接地端GND，因此互容C m1及C m3的充电方向相反，两者对检测操作所造成的影响可互相抵消。此外，互容C m2的两端都会耦接到操作电压VDD因此不会储存电荷，也不会对检测操作造成影响。
综上所述，本申请的实施例所提供的检测电路可以通过控制切换电路，使得不同感测电容之间的互容能够互相抵消或不产生作用，因此可以提升检测电路的准确度。此外，本申请的检测电路还可以利用不同的感测电容来抵消因为温度等外界共模干扰所造成的误差，使得检测电压信号只会与人体等效电容有关，从而增加有效判读数值的范 围，达到提高有效感测范围的目的。
本申请还提供了一种芯片及电子装置，例如耳机。由于芯片及电子装置中的检测电路所产生的电压检测信号可以精准地呈现出人体接近时感测电容值的变化，而不会受到温度变化及互容的干扰，因此可以用来进行电容式的触控检测、电容式的入耳检测、电容式的压力检测等，而本申请的芯片及电子装置便可依据应用的不同，进行后续的操作，例如接听电话、播放或暂停音乐等。
上文的叙述简要地提出了本申请某些实施例之特征，而使得本申请所属技术领域具有通常知识者能够更全面地理解本揭示内容的多种态样。本申请所属技术领域具有通常知识者当可明了，其可轻易地利用本揭示内容作为基础，来设计或更动其他工艺与结构，以实现与此处所述之实施方式相同的目的和/或达到相同的优点。本申请所属技术领域具有通常知识者应当明白，这些均等的实施方式仍属于本揭示内容之精神与范围，且其可进行各种变更、替代与更动，而不会悖离本揭示内容之精神与范围。

Claims (23)

  1. 一种检测电路，其特征在于，所述检测电路包括：
    第一输入端，耦接于第一感测电容的第一端；
    第二输入端，耦接于所述第一感测电容的第二端，所述第一感测电容具有第一固有电容值，且所述第一感测电容的感测电容值至少因人体接近所述第一感测电容而改变；
    第三输入端，耦接于第二感测电容的第一端；
    第四输入端，耦接于所述第二感测电容的第二端，所述第二感测电容具有第二固有电容值，且所述第二感测电容的感测电容值至少因人体接近所述第二感测电容而改变；
    差分积分电路，用以在所述检测电路执行检测操作时，根据第一内部节点的电压及第二内部节点的电压进行差分积分以产生检测电压信号；
    第一切换电路，具有第一端、第二端及第三端，所述第一切换电路的所述第一端为所述第一内部节点，所述第一切换电路的所述第二端耦接于所述检测电路的所述第一输入端，所述第一切换电路的所述第三端耦接于接地端，所述第一切换电路用以导通或截止所述检测电路的所述第一输入端与所述第一内部节点之间的电性连接，及导通或截止所述检测电路的所述第一输入端与所述接地端之间的电性连接；
    第二切换电路，耦接于所述检测电路的所述第二输入端、所述第一内部节点及所述接地端，所述第二切换电路用以导通或截止所述检测电路的所述第二输入端与所述第一内部节点之间的电性连接，及导通或截止所述检测电路的所述第二输入端与所述接地端之间的电性连接；
    第三切换电路，耦接于所述第一内部节点及操作电压，所述第三切换电路用以导通或截止所述第一内部节点及所述操作电压之间的电性连接；
    第四切换电路，耦接于所述第一内部节点及所述接地端，所述第四切换电路用以导通或截止所述第一内部节点及所述接地端之间的电性连接；
    第五切换电路，具有第一端、第二端及第三端，第五切换电路的所述第一端为所述第二内部节点，所述第五切换电路的所述第二端耦接于所述检测电路的所述第三输入端，及所述第五切换电路的所述第三端耦接于所述接地端，所述第五切换电路用以导通或截止所述检测电路的所述第三输入端与所述第二内部节点之间的电性连接，及导通或截止所述检测电路的所述第三输入端与所述接地端之间的电性连接；
    第六切换电路，耦接于所述检测电路的所述第四输入端、所述第二内部节点及所述接地端，所述第六切换电路用以导通或截止所述检测电路的所述第四输入端与所述第二内部节点之间的电性连接，及导通或截止所述检测电路的所述第四输入端与所述接地端之间的电性连接；
    第七切换电路，耦接于所述第二内部节点及所述操作电压，所述第七切换电路用以导通或截止所述第二内部节点及所述操作电压之间的电性连接；及
    第八切换电路，耦接于所述第二内部节点及所述接地端，所述第八切换电路用以导通或截止所述第二内部节点及所述接地端之间的电性连接；
    其中：
    所述第一切换电路、所述第二切换电路、所述第三切换电路、所述第四切换电路、所述第五切换电路、所述第六切换电路、所述第七切换电路及所述第八切换电路用以在所述检测操作中使所述第一感测电容及所述第二感测电容充电及放电，以在所述检测操作中消除所述第一感测电容及所述第二感测电容之间的第一互容对所述检测电压信号的影响，使得所述差分积分电路依据所述第一感测电容及所述第二感测电容的感测电容值输出与人体接近有关的所述检测电压信号。
  2. 如权利要求1所述的检测电路，其特征在于，所述第一切换电路包括：
    第一开关，具有第一端、第二端及控制端，所述第一开关的所述 第一端耦接于所述检测电路的所述第一输入端，所述第一开关的所述第二端为所述第一内部节点；及
    第二开关，具有第一端、第二端及控制端，所述第二开关的所述第一端耦接于所述检测电路的所述第一输入端，所述第二开关的所述第二端耦接于所述接地端。
  3. 如权利要求1所述的检测电路，其特征在于，所述第二切换电路包括：
    第三开关，具有第一端、第二端及控制端，所述第三开关的所述第一端耦接于所述检测电路的所述第二输入端，所述第三开关的所述第二端耦接于所述第一内部节点；及
    第四开关，具有第一端、第二端及控制端，所述第四开关的所述第一端耦接于所述检测电路的所述第二输入端，所述第四开关的所述第二端耦接于所述接地端。
  4. 如权利要求1所述的检测电路，其特征在于，所述第五切换电路包括：
    第五开关，具有第一端、第二端及控制端，所述第五开关的所述第一端耦接于所述检测电路的所述第三输入端，所述第五开关的所述第二端为所述第二内部节点；及
    第六开关，具有第一端、第二端及控制端，所述第六开关的所述第一端耦接于所述检测电路的所述第三输入端，所述第六开关的所述第二端耦接于所述接地端。
  5. 如权利要求1所述的检测电路，其特征在于，所述第六切换电路包括：
    第七开关，具有第一端、第二端及控制端，所述第七开关的所述第一端耦接于所述检测电路的所述第四输入端，所述第七开关的所述第二端耦接于所述第二内部节点；及
    第八开关，具有第一端、第二端及控制端，所述第八开关的所述第一端耦接于所述检测电路的所述第四输入端，所述第八开关的所述第二端耦接于所述接地端。
  6. 如权利要求1至5中任一项所述的检测电路，其特征在于，所述差分积分电路具有第一输入端及第二输入端，且所述差分积分电路包括：
    差分放大器，具有第一输入端、第二输入端、第一输出端及第二输出端，所述差分放大器的所述第一输出端及所述第二输出端用以输出所述检测电压信号；
    第一电容，具有第一端及第二端，所述第一电容的所述第一端耦接于所述差分放大器的所述第一输入端，及所述第一电容的所述第二端耦接于所述差分放大器的所述第一输出端；
    第二电容，具有第一端及第二端，所述第二电容的所述第一端耦接于所述差分放大器的所述第二输入端，及所述第二电容的所述第二端耦接于所述差分放大器的所述第二输出端；
    第九切换电路，用以导通或截止所述差分放大器的所述第一输入端及所述差分积分电路的所述第一输入端之间的电性连接；及
    第十切换电路，用以导通或截止所述差分放大器的所述第二输入端及所述差分积分电路的所述第二输入端之间的电性连接。
  7. 如权利要求6所述的检测电路，其特征在于，另包括：
    第三电容，具有第一端及第二端；
    第十一切换电路，用以导通或截止所述第三电容的所述第一端与所述接地端之间的电性连接；
    第十二切换电路，用以导通或截止所述第三电容的所述第一端与所述操作电压之间的电性连接；
    第十三切换电路，用以导通或截止所述第三电容的所述第二端与所述接地端之间的电性连接，及导通或截止所述第三电容的所述第二端与所述操作电压之间的电性连接；
    第十四切换电路，用以导通或截止所述第三电容的所述第一端与所述第一内部节点之间的电性连接；
    第四电容，具有第一端及第二端；
    第十五切换电路，用以导通或截止所述第四电容的所述第一端与 所述接地端之间的电性连接；
    第十六切换电路，用以导通或截止所述第四电容的所述第一端与所述操作电压之间的电性连接；
    第十七切换电路，用以导通或截止所述第四电容的所述第二端与所述接地端之间的电性连接，及导通或截止所述第四电容的所述第二端与所述操作电压之间的电性连接；及
    第十八切换电路，用以导通或截止所述第四电容的所述第一端与所述第二内部节点之间的电性连接；
    其中，所述差分积分电路的所述第一输入端耦接于所述第一内部节点，所述差分积分电路的所述第二输入端耦接于所述第二内部节点。
  8. 如权利要求7所述的检测电路，其特征在于，所述检测操作依序包括第一阶段及第二阶段，所述第一阶段包括：
    对所述第一感测电容及所述第三电容进行充电、使所述第一感测电容及所述第三电容中的电荷重新分配以使所述第一内部节点的所述电压与所述第一感测电容的所述第一固有电容值及所述第三电容的电容值无关；
    对所述第二感测电容及所述第四电容进行充电、使所述第二感测电容及所述第四电容中的电荷重新分配，以使所述第二内部节点的所述电压与所述第二感测电容的所述第二固有电容值及所述第四电容的电容值无关；及
    在所述第一感测电容及所述第三电容中的电荷重新分配后，和所述第二感测电容及所述第四电容中的电荷重新分配后，所述差分积分电路对所述第一内部节点的所述电压及所述第二内部节点的所述电压进行差分积分；
    其中，在所述第一阶段中，所述检测电路的所述第三输入端被耦接至接地端，使得所述第二内部节点的所述电压与因温度所引起的电容变化有关而与人体接近所述第二感测电容所引起的电容变化无关，且所述第一内部节点的所述电压与因人体 接近所述第一感测电容及温度所引起的电容变化有关；
    所述第二阶段包括：
    对所述第一感测电容及所述第三电容进行充电、使所述第一感测电容及所述第三电容中的电荷重新分配以使所述第一内部节点的所述电压与所述第一感测电容的所述第一固有电容值及所述第三电容的电容值无关；
    对所述第二感测电容及所述第四电容进行充电、使所述第二感测电容及所述第四电容中的电荷重新分配，以使所述第二内部节点的所述电压与所述第二感测电容的所述第二固有电容值及所述第四电容的电容值无关；及
    在所述第一感测电容、所述第三电容、所述第二感测电容及所述第四电容中的电荷重新分配后，所述差分积分电路对所述第一内部节点的所述电压及所述第二内部节点的所述电压进行差分积分；
    其中，在所述第二阶段中，所述检测电路的所述第一输入端被耦接至接地端，使得所述第一内部节点的所述电压与因温度所引起的电容变化有关而与人体接近所述第一感测电容所引起的电容变化无关，且所述第二内部节点的所述电压与因温度及人体接近所述第二感测电容所引起的电容变化有关。
  9. 如权利要求8所述的检测电路，其特征在于：
    在所述第一阶段中，当所述第一感测电容及所述第三电容进行所述充电及当所述第二感测电容及所述第四电容进行所述充电时，所述第一内部节点及所述第二内部节点处于相同的电位，使所述第一互容的两端处于相同的电位，从而使所述第一互容不储存电荷；及
    在所述第二阶段中，当所述第一感测电容及所述第三电容进行所述充电及当所述第二感测电容及所述第四电容进行所述充电时，所述第一内部节点及所述第二内部节点处于相同的电位， 使所述第一互容的两端处于相同的电位，从而使所述第一互容不储存电荷。
  10. 如权利要求7所述的检测电路，其特征在于，所述第三电容的电容值是所述第一感测电容的所述第一固有电容值的三分之一，所述第四电容的电容值是所述第二感测电容的所述第二固有电容值的三分之一。
  11. 如权利要求10所述的检测电路，其特征在于：
    所述第三电容包括第一可变电容或第一电容阵列，其中所述第一可变电容或所述第一电容阵列的电容值可通过第一控制信号来依据所述第一感测电容的固有电容值而被改变；及
    所述第四电容包括第二可变电容或第二电容阵列，其中所述第二可变电容或所述第二电容阵列的电容值可通过第二控制信号来依据所述第二感测电容的固有电容值而被改变。
  12. 如权利要求7所述的检测电路，其特征在于，所述第十三切换电路包括：
    第九开关，具有第一端、第二端及控制端，所述第九开关的所述第一端耦接于所述第三电容的所述第二端，所述第九开关的所述第二端耦接于所述操作电压；及
    第十开关，具有第一端、第二端及控制端，所述第十开关的所述第一端耦接于所述第三电容的所述第二端，所述第十开关的所述第二端耦接于所述接地端。
  13. 如权利要求7所述的检测电路，其特征在于，所述第十七切换电路包括：
    第十一开关，具有第一端、第二端及控制端，所述第十一开关的所述第一端耦接于所述第四电容的所述第二端，所述第十一开关的所述第二端耦接于所述操作电压；及
    第十二开关，具有第一端、第二端及控制端，所述第十二开关的所述第一端耦接于所述第四电容的所述第二端，所述第十二 开关的所述第二端耦接于所述接地端。
  14. 如权利要求6所述的检测电路，其特征在于，另包括：
    第十九切换电路，用以导通或截止所述第一内部节点及所述差分积分电路的所述第一输入端之间的电性连接；及
    第二十切换电路，用以导通或截止所述第二内部节点及所述差分积分电路的所述第二输入端之间的电性连接。
    第五输入端，耦接于第三感测电容的第一端；
    第六输入端，耦接于所述第三感测电容的第二端，所述第三感测电容具有第三固有电容值，且所述第三感测电容的感测电容值至少因人体接近所述第三感测电容而改变；
    第七输入端，耦接于第四感测电容的第一端；
    第八输入端，耦接于所述第四感测电容的第二端，所述第四感测电容具有第四固有电容值，且所述第四感测电容的感测电容值至少因人体接近所述第四感测电容而改变；
    第二十一切换电路，用以导通或截止所述差分积分电路的所述第一输入端及所述接地端之间的电性连接；
    第二十二切换电路，用以导通或截止所述差分积分电路的所述第一输入端及所述操作电压之间的电性连接；
    第二十三切换电路，用以导通或截止所述第五输入端与所述接地端之间的电性连接，及导通或截止所述第五输入端与所述差分积分电路的所述第一输入端之间的电性连接；
    第二十四切换电路，用以导通或截止所述第六输入端与所述接地端之间的电性连接，及导通或截止所述第六输入端与所述差分积分电路的所述第一输入端之间的电性连接；
    第二十五切换电路，用以导通或截止所述差分积分电路的所述第二输入端及所述操作电压之间的电性连接；
    第二十六切换电路，用以导通或截止所述差分积分电路的所述第二输入端及所述接地端之间的电性连接；
    第二十七切换电路，用以导通或截止所述第七输入端与所述接地端之间的电性连接，及导通或截止所述第七输入端与所述差 分积分电路的所述第二输入端之间的电性连接；及
    第二十八切换电路，用以导通或截止所述第八输入端与所述接地端之间的电性连接，及导通或截止所述第八输入端与所述差分积分电路的所述第二输入端之间的电性连接。
  15. 如权利要求14所述的检测电路，其特征在于，所述检测操作依序包括第一阶段及第二阶段，所述第一阶段包括：
    对所述第一感测电容进行充电、对所述第三感测电容进行放电、使所述第一感测电容及所述第三感测电容中的电荷重新分配，以使所述第一内部节点的所述电压与所述第一感测电容的所述第一固有电容值、所述第三感测电容的所述第三固有电容值及温度所引起的电容变化无关；
    对所述第四感测电容进行充电、对所述第二感测电容进行放电、使所述第二感测电容及所述第四感测电容中的电荷重新分配，以使所述第二内部节点的所述电压与所述第二感测电容的所述第二固有电容值、所述第四感测电容的所述第四固有电容值及温度所引起的电容变化无关；及
    在所述第一感测电容及所述第三感测电容中的电荷重新分配后和所述第二感测电容及所述第四感测电容中的电荷重新分配后，所述差分积分电路对所述第一内部节点的所述电压及所述第二内部节点的所述电压进行差分积分；
    其中，在对所述第一阶段中，所述检测电路的所述第五输入端及所述第七输入端被耦接至接地端，以使所述第一内部节点的所述电压与因人体接近所述第一感测电容所引起的电容变化有关而与人体接近所述第三感测电容所引起的电容变化无关，且使所述第二内部节点的所述电压与因人体接近所述第二感测电容所引起的电容变化有关而与人体接近所述第四感测电容所引起的电容变化无关；
    所述第二阶段包括：
    对所述第三感测电容进行充电、对所述第一感测电容进行放电、使所述第一感测电容及所述第三感测电容中的电荷重新分配，以使所述第一内部节点的所述电压与所述第一感测电容的所述第一固有电容值、所述第三感测电容的所述第三固有电容值及温度所引起的电容变化无关；
    对所述第二感测电容进行充电、对所述第四感测电容进行放电、使所述第二感测电容及所述第四感测电容中的电荷重新分配，以使所述第二内部节点的所述电压与所述第二感测电容的所述第二固有电容值、所述第四感测电容的所述第四固有电容值及温度所引起的电容变化无关；及
    在所述第一感测电容及所述第三感测电容中的电荷重新分配后，和所述第二感测电容及所述第四感测电容中的电荷重新分配后，所述差分积分电路对所述第一内部节点的所述电压及所述第二内部节点的所述电压进行差分积分；
    其中，在所述第二阶段中，所述检测电路的所述第一输入端及所述第三输入端被耦接至接地端，以使所述第一内部节点的所述电压与因人体接近所述第三感测电容所引起的电容变化有关而与人体接近所述第一感测电容所引起的电容变化无关，且使所述第二内部节点的所述电压与因人体接近所述第四感测电容温度所引起的电容变化有关而与人体接近所述第二感测电容所引起的电容变化无关。
  16. 如权利要求15所述的检测电路，其特征在于，在所述检测操作中，所述第二感测电容及所述第三感测电容之间的第二互容的两端是处于相同的电位，且所述第三感测电容及所述第四感测电容之间的第三互容与所述第一互容对所述检测电压信号的影响互相抵消，使得所述检测电压信号与所述第一互容、所述第二互容及所述第三互容无关。
  17. 如权利要求14所述的检测电路，其特征在于，所述第二十三切换电路包括：
    第十三开关，具有第一端、第二端及控制端，所述第十三开关的所述第一端耦接于所述检测电路的所述第五输入端，所述第十三开关的所述第二端耦接于所述差分积分电路的所述第一输入端；及
    第十四开关，具有第一端、第二端及控制端，所述第十四开关的所述第一端耦接于所述检测电路的所述第五输入端，所述第十四开关的所述第二端耦接于所述接地端。
  18. 如权利要求14所述的检测电路，其特征在于，所述第二十四切换电路包括：
    第十五开关，具有第一端、第二端及控制端，所述第十五开关的所述第一端耦接于所述检测电路的所述第六输入端，所述第十五开关的所述第二端耦接于所述差分积分电路的所述第一输入端；及
    第十六开关，具有第一端、第二端及控制端，所述第十六开关的所述第一端耦接于所述检测电路的所述第六输入端，所述第十六开关的所述第二端耦接于所述接地端。
  19. 如权利要求14所述的检测电路，其特征在于，所述第二十七切换电路包括：
    第十七开关，具有第一端、第二端及控制端，所述第十七开关的所述第一端耦接于所述检测电路的所述第七输入端，所述第十七开关的所述第二端耦接于所述差分积分电路的所述第二输入端；及
    第十八开关，具有第一端、第二端及控制端，所述第十八开关的所述第一端耦接于所述检测电路的所述第七输入端，所述第十八开关的所述第二端耦接于所述接地端。
  20. 如权利要求14所述的检测电路，其特征在于，所述第二十八切换电路包括：
    第十九开关，具有第一端、第二端及控制端，所述第十九开关的所述第一端耦接于所述检测电路的所述第八输入端，所述第 十九开关的所述第二端耦接于所述差分积分电路的所述第二输入端；及
    第二十开关，具有第一端、第二端及控制端，所述第二十开关的所述第一端耦接于所述检测电路的所述第八输入端，所述第二十开关的所述第二端耦接于所述接地端。
  21. 如权利要求6所述的检测电路，其特征在于，差分积分电路另包括：
    第一重置切换开关，用以在重置操作中，导通所述差分放大器的所述第一输入端及所述差分放大器的所述第一输出端之间的电性连接，及在所述检测操作中，截止所述差分放大器的所述第一输入端及所述差分放大器的所述第一输出端之间的所述电性连接；及
    第二重置切换开关，用以在重置操作中导通所述差分放大器的所述第二输入端及所述差分放大器的所述第二输出端之间的电性连接，及在所述检测操作中，截止所述差分放大器的所述第二输入端及所述差分放大器的所述第二输出端之间的所述电性连接。
  22. 一种芯片，包括权利要求1-21中任意一项所述的检测电路及用于读取所述检测电路输出的检测电压信号的读取电路。
  23. 一种电子装置，其特征在于，包含：
    如权利要求1-21中任一项所述的检测电路。
PCT/CN2021/073214 2021-01-22 2021-01-22 检测电路、芯片及相关电子装置 WO2022155878A1 (zh)

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