WO2019169555A1 - Circuit de détection de capacité, dispositif de détection tactile et appareil terminal - Google Patents

Circuit de détection de capacité, dispositif de détection tactile et appareil terminal Download PDF

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Publication number
WO2019169555A1
WO2019169555A1 PCT/CN2018/078165 CN2018078165W WO2019169555A1 WO 2019169555 A1 WO2019169555 A1 WO 2019169555A1 CN 2018078165 W CN2018078165 W CN 2018078165W WO 2019169555 A1 WO2019169555 A1 WO 2019169555A1
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Prior art keywords
capacitor
circuit
touch
capacitance
switch
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PCT/CN2018/078165
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English (en)
Chinese (zh)
Inventor
范硕
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深圳市汇顶科技股份有限公司
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Priority to CN201880000137.3A priority Critical patent/CN110463041B/zh
Priority to PCT/CN2018/078165 priority patent/WO2019169555A1/fr
Publication of WO2019169555A1 publication Critical patent/WO2019169555A1/fr

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches
    • H03K17/955—Proximity switches using a capacitive detector

Definitions

  • the present application relates to the field of electronic technologies, and in particular, to a circuit for capacitance detection, a touch detection device, and a terminal device.
  • Capacitive sensors are widely used in the field of human-computer interaction of electronic products. Specifically, a capacitance is formed between the detecting electrode and the ground. When a conductor (such as a finger) approaches or touches the detecting electrode, the capacitance between the detecting electrode and the ground is detected. A change occurs, and the information on the proximity of the conductor or the touch detection electrode is obtained by detecting the amount of change in the capacitance, thereby judging the user's operation. The performance of the capacitance detection circuit directly affects the user's operating experience. Therefore, improving the anti-interference ability of the capacitance detection circuit has become an urgent problem to be solved.
  • the embodiment of the present application provides a circuit, a touch detection device, and a terminal device for capacitance detection, which can improve the anti-interference capability of the capacitance detection circuit.
  • a capacitance detecting circuit including a first charging and discharging circuit, the first charging and discharging circuit including a common gate transistor, and the transistor is connected to a touch capacitor.
  • the first charge and discharge circuit is configured to clear the charge on the touch capacitor in a first stage, and charge the touch capacitor to a preset voltage through the transistor in a second stage.
  • the circuit for capacitance detection in the embodiment of the present application since the touch capacitor is charged by the common gate transistor, the circuit has a lower impedance on the side of the touch capacitor, so that external interference, especially low frequency When the interference occurs, the influence of the interference signal on the capacitance of the touch capacitor can be reduced, and the anti-interference ability of the circuit for capacitance detection can be improved.
  • the transistor is an N-type metal oxide semiconductor MOS transistor.
  • a gate of the transistor is connected to a fixed level, a drain of the transistor is connected to a power source, and a source of the transistor is connected to the touch capacitor, wherein When the transistor charges the touch capacitor, the transistor is in a saturation region.
  • the first charging and discharging circuit further includes a first switch and a second switch.
  • the drain of the transistor is connected to a power source, the source of the transistor is connected to one end of the touch capacitor through the first switch, the other end of the touch capacitor is grounded, and the second switch is The touch capacitors are connected in parallel.
  • the first switch in the first phase, is turned off, the second switch is closed; in the second phase, the second switch is turned off, The first switch is closed until the voltage on the touch capacitor reaches the preset voltage.
  • the first charging and discharging circuit is further configured to:
  • the capacitance detecting circuit further includes a comparator, an input end of the comparator is connected to the touch capacitor, and an input voltage of the other input end of the comparator Equal to the preset voltage.
  • the capacitance detecting circuit further includes an analog-to-digital conversion circuit, configured to convert a voltage signal of the touch capacitor into a digital signal.
  • the capacitance detecting circuit further includes a voltage buffer, configured to buffer a voltage signal corresponding to the touch capacitor.
  • the capacitance detecting circuit further includes a processing circuit, configured to determine a capacitance of the touch capacitor according to a voltage signal corresponding to the touch capacitor.
  • the capacitance detecting circuit further includes an integrating capacitor and a second charging and discharging circuit, the second charging and discharging circuit includes a current source, and the current source is connected to the integrating capacitor .
  • the second charging and discharging circuit is configured to clear a charge on the integrating capacitor in the first stage, and pass the current in the second stage.
  • the source charges the integrating capacitor.
  • the duration of charging the integrating capacitor by the current source is equal to the length of time that the transistor charges the touch capacitor, so that the capacitance variation of the touch capacitor is related to the capacitance variation of the integrating capacitor.
  • the second charging and discharging unit further includes a third switch and a fourth switch.
  • one end of the current source is connected to a power source
  • the other end of the current source is connected to one end of the integrating capacitor through the third switch
  • the other end of the integrating capacitor is grounded
  • the fourth switch is The integrating capacitors are connected in parallel.
  • the third switch in the first phase, is turned off, the fourth switch is closed; in the second phase, the fourth switch is turned off, The third switch is closed until the voltage on the touch capacitor reaches the preset voltage.
  • the second charging and discharging circuit is configured to charge the integrating capacitor to a power supply voltage in the first phase, and pass the current source in the second phase. Discharging the integrating capacitor.
  • the duration of the current source discharging the integrating capacitor is equal to the length of time that the transistor charges the touch capacitor, so that the capacitance change amount of the touch capacitor is associated with the capacitance change amount of the integrating capacitor.
  • the second charging and discharging unit further includes a third switch and a fourth switch.
  • the one end of the integrating capacitor is connected to a power source
  • the other end of the integrating capacitor is connected to one end of the current source through the third switch
  • the other end of the current source is grounded
  • the fourth switch is The integrating capacitors are connected in parallel.
  • the third switch in the first phase, is turned off, the fourth switch is closed; in the second phase, the fourth switch is turned off, The third switch is closed until the voltage on the touch capacitor reaches the preset voltage.
  • the first charging and discharging circuit and the second charging and discharging circuit are further configured to perform operations in the first phase and the second phase multiple times.
  • the capacitance detecting circuit further includes a comparator, an input end of the comparator is connected to the touch capacitor, and an input voltage of the other input end of the comparator Equal to the preset voltage.
  • the capacitance detecting circuit further includes an analog-to-digital conversion circuit, configured to convert a voltage signal of the integrating capacitor into a digital signal.
  • the capacitance detecting circuit further includes a voltage buffer, configured to buffer a voltage signal corresponding to the integrating capacitor.
  • the capacitance detecting circuit further includes a processing circuit, configured to determine a capacitance of the touch capacitor according to a voltage signal corresponding to the integrating capacitor.
  • the capacitance detecting circuit is applied to a capacitive sensor, and the touch capacitor is a sensor capacitance of the capacitive sensor.
  • the embodiment of the present application provides a touch detection device, including the capacitance detection circuit according to the first aspect or any optional implementation of the first aspect, wherein the touch detection device is determined according to the capacitance detection circuit.
  • the amount of capacitance change of the touch capacitor relative to the base capacitor determines a touch position of the user.
  • an embodiment of the present application provides a terminal device, including the touch detection device according to the second aspect.
  • FIG. 1 is a schematic diagram of a conventional capacitance detecting circuit.
  • FIG. 2 is a schematic block diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of an equivalent circuit of a MOS transistor included in a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 5 is an equivalent circuit diagram when an interference signal exists in a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 8 is another schematic structural diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 9 is another schematic structural diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 10 is another schematic structural diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 11 is another schematic structural diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 12 is another schematic structural diagram of a circuit for capacitance detection according to an embodiment of the present application.
  • FIG. 13 is a schematic block diagram of a touch detection apparatus according to an embodiment of the present application.
  • the technical solutions of the embodiments of the present application can be applied to various devices that use touch, such as an active pen, a capacitive pen, a mobile terminal, a computer, a home appliance, and the like.
  • the circuit for capacitance detection of the embodiment of the present application may be disposed in various touch devices for detecting a capacitance change of a touch capacitor, that is, a capacitor to be tested (detected capacitor), thereby detecting a touch generated by the touch. Pressure changes, etc.
  • the touch capacitor here refers to a capacitive sensor disposed on the touch panel.
  • the capacitance change of the touch capacitor can be either a relative value or an absolute value.
  • the capacitance change of the touch capacitor is the absolute value of the capacitance.
  • a “capacitor” may also be referred to simply as a “capacitor”, and accordingly, the capacitance of a capacitor may also be referred to as a capacitance value.
  • the capacitance of a capacitor and a capacitor will be described as an example.
  • a capacitance is formed between the touch capacitor Cx and the ground.
  • a conductor such as a finger approaches or touches the touch capacitor Cx
  • the capacitance between the touch capacitor Cx and the ground changes, according to the touch.
  • the capacitance change amount ⁇ C of the capacitor capacitor Cx can acquire information on the conductor approaching or touching the touch capacitor Cx, thereby judging the user's operation.
  • the reference ground of the finger is not the same ground as the reference ground of the chip circuit.
  • the reference ground of the finger will be relatively clean, and the reference ground of the chip circuit will have a large jitter with respect to the ideal ground due to its own or proximity to other electronic devices.
  • all the devices are the ground of the reference chip circuit.
  • the reference ground of the finger is jittery. The interference signal caused by this jitter limits the Signal Noise Ratio (SNR) of the signal collected by the capacitance detection circuit.
  • SNR Signal Noise Ratio
  • the capacitance detecting circuit 100 shown in FIG. 1 includes a current source 110 and a touch capacitor Cx.
  • One end of the current source 110 is connected to the power source V DD , and the other end is connected to the touch capacitor Cx through the switch S1.
  • S2 is connected in parallel with the touch capacitor Cx.
  • the switch S1 is closed and S2 is off, the charge on the touch capacitor Cx is cleared.
  • the switch S2 is closed and S1 is off, the current source 110 charges the touch capacitor Cx.
  • the capacitance of the touch capacitor Cx is equal to the initial capacitance.
  • the capacitance of the touch capacitor Cx changes, and the capacitance change amount is ⁇ . C.
  • the external interference signal introduced when the finger is touched may affect the detection of ⁇ C. Therefore, it is necessary to reduce the influence of the interference signal on the capacitance detection of the touch capacitor Cx.
  • the interference signal brought by the finger approaching or touching the touch capacitor Cx may include two parts, that is, an interference signal of high frequency heat drying property and an interference signal of low frequency flash noise property.
  • an interference signal of high frequency heat drying property For the high-frequency heat-drying noise signal, it can be eliminated by multiple sampling and averaging or analog integration. However, it is still impossible to eliminate the interference signal of the low frequency flicker property.
  • the embodiment of the present application proposes to charge and discharge the touch capacitor Cx in the capacitance detecting circuit by using a common gate transistor, so that the circuit is in the touch capacitor
  • the side has a lower impedance, so that when there is external interference, especially low frequency interference, the influence of the interference signal on the capacitance detection of the touch capacitor can be reduced.
  • FIG. 2 is a schematic diagram of a circuit 200 for capacitance detection in accordance with an embodiment of the present application.
  • This circuit 200 can be applied to any scene.
  • the circuit 200 for capacitance detection is suitable for use in a touch detection device for detecting touch information of a user.
  • the touch capacitor Cx can be regarded as a capacitor formed by the electrode of the touch channel and the ground.
  • the touch capacitor Cx can also be referred to as a detection capacitor or a detection electrode.
  • the circuit 200 includes a touch capacitor Cx and a first charging and discharging circuit 210.
  • the first charging and discharging circuit 210 includes a common gate transistor 211, and the transistor 211 is connected to the touch capacitor Cx.
  • the first charging and discharging circuit 210 is configured to clear the charge on the touch capacitor Cx in the first stage, and charge the touch capacitor Cx through the transistor 211 in the second stage.
  • the first charging and discharging circuit 210 clears the charge on the touch capacitor Cx in the first stage, and charges the touch capacitor Cx to the preset voltage V R through the transistor 211 in the second stage.
  • the transistor 211 charges the touch capacitor Cx to the preset voltage V R for T1; when a finger approaches or touches the touch capacitor Cx, the transistor 211
  • the time for charging the touch capacitor Cx to the preset voltage V R is T2.
  • the capacitance of the touch capacitor Cx changes, and the capacitance change amount ⁇ C is generated. Therefore, the T2 and T1 are passed. The relationship between the two can be used to determine the capacitance change of the touch capacitor Cx.
  • the transistor 211 may be, for example, an N-type metal oxide semiconductor (MOS) transistor, such as an N-channel depletion MOS transistor or an N-channel enhancement MOS.
  • MOS metal oxide semiconductor
  • the gate (Gate, abbreviated as G) of the transistor 211 is connected to a fixed level V bn , and the drain (Drain, abbreviated as D) of the transistor 211 is connected to the power source V DD .
  • the source (Source, abbreviated as S) of the transistor 211 is connected to the touch capacitor Cx.
  • the first charging and discharging circuit 210 further includes a first switch S1 and a second switch S2.
  • the source of the transistor 211 is connected to one end of the touch capacitor Cx through S1, the other end of the touch capacitor Cx is grounded, and the S2 is connected in parallel with the touch capacitor Cx.
  • FIG. 3 is intended to help those skilled in the art to better understand the embodiments of the present application, and not to limit the scope of the embodiments of the present application.
  • the transistor 211 charges the touch capacitor Cx.
  • the transistor 211 operates in a saturation region.
  • the fixed level V bn connected to the gate of the transistor 211 should satisfy V bn +V th >V R
  • Vth is the threshold voltage of the transistor 211.
  • a transistor for common charging of the touch capacitor Cx in the embodiment of the present application is a common gate transistor 211.
  • the current source 110 in FIG. 1 charges the touch capacitor Cx, the current during charging remains unchanged.
  • the gate and the source of the transistor 211 are small because the voltage on the touch capacitor Cx is small at the beginning of charging.
  • the voltage V GS between the two is large, and the charging current is also large.
  • V GS gradually becomes smaller, and the charging current also becomes smaller. It can be seen that the charging current in the process is not constant, but varies. This makes the charging process of the touch capacitor Cx in the embodiment of the present application greatly different from the charging process of the touch capacitor Cx in FIG.
  • N-type MOS transistor 211 having the transistor 211 as a common gate will be described as an example.
  • the MOS transistor 211 when V GS - V th ⁇ V DS and V DS > V th are satisfied, the MOS transistor is in a saturation region.
  • V th is the threshold voltage of the MOS transistor 211
  • V GS is the voltage between the gate and the source of the MOS transistor 211
  • V DS is the voltage between the drain and the source of the MOS transistor 211. Since the MOS transistor is in the saturation region, the resistance seen from the V DD end is very large, that is, when charging the Cx through the MOS transistor 211, the charging current can be considered to be free from noise on the V DD and The impact of interference.
  • the impedance of the source of the MOS transistor 211 is seen to be approximately equal to the MOS transistor 211.
  • the reciprocal of the transconductance is 1/g m , where g m is the transconductance of the MOS transistor 211.
  • the value of this impedance is small, both at the Kohm level.
  • the current source 110 is used in FIG. 1 to charge the touch capacitor Cx
  • the impedance seen by Cx upwards generally comes at the Mohm level. Therefore, when the MOS transistor 211 is used to charge the touch capacitor Cx, a relatively low impedance value point can be obtained.
  • the low impedance point is less affected by the interference.
  • FIG. 5 is an equivalent circuit diagram when an interference signal is present in the circuit 200 for capacitance detection.
  • Ro is the equivalent resistance of the MOS transistor 211.
  • Vx is independent of Ro, and the high frequency noise signal of the MOS transistor 211 has no influence on the capacitance of the touch capacitor Cx.
  • the circuit 200 for capacitance detection may further include an integrating capacitor C I and a second charging and discharging circuit 220.
  • the second charging and discharging circuit 220 includes a current source 221, and the current Source 221 is coupled to the integrating capacitor C I .
  • the second charging and discharging circuit 220 is configured to clear the charge on the integrating capacitor C 1 in the first stage, and charge or discharge the integrating capacitor C 1 through the current source 221 in the second stage.
  • the duration of charging or discharging the integrating capacitor C 1 by the current source 221 is equal to the length of time the transistor 211 charges the touch capacitor Cx, so that the capacitance variation of the touch capacitor Cx is associated with the integrating capacitor.
  • the amount of capacitance change of C I is, the capacitance change amount of the integrating capacitor C I can reflect the capacitance change amount ⁇ C of the touch capacitor Cx.
  • FIG. 7 to FIG. 12 are intended to help those skilled in the art to better understand the embodiments of the present application, and do not limit the scope of the embodiments of the present application.
  • the second charge-discharge circuit 220 of the charge on the integrating capacitor C I is cleared in the first phase, and a current source through the integration capacitor C 221 I the charge during the second phase.
  • the duration of charging the integrating capacitor C 1 by the current source 221 is equal to the length of time the transistor 211 charges the touch capacitor Cx, so that the capacitance variation of the touch capacitor Cx is related to the capacitance change of the integrating capacitor C I . amount, whereby the change in the capacitance of the capacitor Cx touch may be determined based on changes in the capacitance of the integrating capacitor C I.
  • the duration of the charging of the integrating capacitor C 1 by the current source 221 is equal to the length of time the transistor 211 charges the touch capacitor Cx, so that the capacitance variation of the touch capacitor Cx is related to the capacitance of the integrating capacitor C I .
  • the amount of change that is, the amount of change in capacitance of the touch capacitor Cx is related to the amount of change in capacitance of the integrating capacitor C I , or the amount of change in capacitance of the integrating capacitor C I can reflect the amount of change in capacitance of the touch capacitor Cx.
  • the capacitance change amount of the integrating capacitor C I depends on the charging duration thereof, and the charging duration of the integrating capacitor C I depends on the charging duration of the touch capacitor Cx, and the charging duration of the touch capacitor Cx is The duration of the charging to the preset voltage V R , during which the capacitance of the touch capacitor Cx changes due to charging, so that the capacitance change of the integrating capacitor C I and the capacitance change of the touch capacitor Cx
  • the capacitance change of the touch capacitor Cx can be known by measuring the capacitance of the integrating capacitor C I .
  • the second charging and discharging unit 220 further includes a third switch S3 and a fourth switch S4.
  • one end of the current source 221 is connected to the power source V DD
  • the other end of the current source 221 is connected to one end of the integrating capacitor C I through S3
  • the other end of the integrating capacitor C I is grounded
  • S4 is connected in parallel with the integrating capacitor C I .
  • S1 and S3 are disconnected, and S2 and S4 are closed. Since S2 is connected across the touch capacitor Cx, S4 is connected across the integrating capacitor C I , so that the touch capacitor Cx and the integrating capacitor C I are discharged to zero, that is, the touch capacitor Cx and the integrating capacitor C. The charge on I is cleared.
  • the measured capacitance of the integrating capacitor C I is assumed to be A
  • the measured capacitance of the integrating capacitor C I assumption For B then the capacitance change of the integrating capacitor C I is the difference between A and B. Since the values of A and B are dependent on the length of time that the current source 221 charges the integrating capacitor C 1 , the charging duration is equal to the transistor. 211 charges the touch capacitor Cx to the preset capacitor V R for a period of time, so the capacitance change amount ⁇ C of the touch capacitor Cx can be determined according to the difference between A and B.
  • the current source 221 for charging the integrating capacitor C 1 in FIG. 7 may specifically be a P-type MOS transistor as shown in FIG. 8, but the present application is not limited thereto.
  • the current source 221 can also be replaced by a voltage source or resistor for charging the integrating capacitor C I .
  • the second charge and discharge circuit 220 charges the integrating capacitor C 1 to the power supply voltage V DD in the first stage, and discharges the integrating capacitor C I through the current source 221 in the second stage.
  • the duration of the current source 221 discharging the integrating capacitor C I is equal to the length of time the transistor 211 charges the touch capacitor Cx, so that the capacitance variation of the touch capacitor Cx is related to the capacitance change of the integrating capacitor C I . amount, whereby the change in the capacitance of the capacitor Cx touch may be determined based on changes in the capacitance of the integrating capacitor C I.
  • the second charging and discharging unit 220 further includes a third switch S3 and a fourth switch S4.
  • the other end of the integration capacitor C I is a terminating power supply V DD, the integrating capacitor C I through S3 connected to one end of the current source 221, the other end of the current source 221, S4 in parallel with the integration capacitor C I .
  • the measured capacitance of the integrating capacitor C I is assumed to be A
  • the measured capacitance of the integrating capacitor C I assumption For B then the capacitance change amount of the integrating capacitor C I is the difference between A and B. Since the values of A and B depend on the duration of the current source 221 discharging the integrating capacitor C I , the discharge duration is the transistor 211 .
  • the touch the capacitor Cx is charged to a predetermined length when the capacitance experienced by V R, thereby determining the amount of change in the capacitance of the integrating capacitor C I the values of a and B, and the amount of change of capacitance of the integrating capacitor C I to determine the The capacitance change amount ⁇ C of the touch capacitor Cx.
  • the current source 221 for discharging the integrating capacitor C I in FIG. 9 may specifically be a P-type MOS transistor as shown in FIG. 10, but the present application is not limited thereto.
  • the current source 221 can also be replaced by a voltage source or a resistor for discharging the integrating capacitor C I .
  • the circuit 200 may repeatedly perform the operations in the first phase and the second phase N times, and respectively obtain the integrating capacitor C obtained in the N operations.
  • the average value of the N capacitance values of I is taken as the actual measured value of the capacitance of the integrating capacitor C I , that is, the above-mentioned A and B are the average values of the N capacitance values of the integrating capacitor C I obtained after N operations. .
  • the circuit 200 for capacitance detection may further include a comparator 230.
  • a comparator 230 For example, as shown in FIG. 11, one input terminal (for example, the non-inverting input terminal) of the comparator 230 is connected to the touch capacitor Cx, and the input voltage is the voltage V Cx corresponding to the touch capacitor Cx , and the other input end of the comparator 230.
  • the input voltage (eg, the inverting input) is equal to the predetermined voltage V R .
  • the output of the comparator 230 is connected to the control module 270.
  • the control module 270 detects that the signal output by the comparator 230 is inverted, the switches S1 to S4 can be controlled accordingly. Thereby, charging and discharging of the touch capacitor Cx and the integrating capacitor C I are achieved.
  • the transistor 211 charges the touch capacitor Cx to the voltage of the touch capacitor Cx to reach the preset voltage V R , the output signal of the comparator 230 is inverted, and the control module 270 controls the S1 and S3 to be disconnected. Therefore, the first charging and discharging circuit 211 and the second charging and discharging circuit 221 stop charging and discharging the touch capacitor Cx and the integrating capacitor C I , respectively.
  • the non-inverting input terminal and the inverting input terminal of the comparator 230 can be exchanged as long as the signal state outputted by the comparator 230 can be detected to be inverted.
  • the capacitive sensing circuit 200 further includes analog to digital conversion circuit (Analog to Digital Converter, ADC) 250, converts the voltage signal to the integrating capacitor C I to a digital signal.
  • ADC Analog to Digital Converter
  • the capacitance detecting circuit 200 further includes a voltage buffer 240 for buffering the voltage signal corresponding to the integrating capacitor C I .
  • the voltage buffer 240 can be used to drive the analog to digital conversion circuit 250.
  • An input terminal (for example, a non-inverting input terminal) of the voltage buffer 240 can be connected to the integrating capacitor C I , the input voltage of which is the voltage V CI of the integrating capacitor C I , and the output terminal is connected to the analog-to-digital conversion circuit 250, thereby A voltage signal obtained by charging or discharging the integrating capacitor C I is transmitted to the analog to digital conversion circuit 250.
  • the capacitance detecting circuit 200 further includes a processing circuit 260 for determining a capacitance of the touch capacitor Cx according to the voltage signal V CI corresponding to the integrating capacitor C I .
  • the capacitance detecting circuit 200 can be applied to a capacitive sensor.
  • the touch capacitor Cx is a sensor capacitance of the capacitive sensor.
  • the embodiment of the present application is described by taking the first charging and discharging circuit 210 to charge the touch capacitor Cx through the transistor 211 as an example.
  • the first charging and discharging circuit 210 can also touch the transistor 211 of the capacitor Cx discharges, and the second charging and discharging circuit 220 through current source 221 pairs long integration capacitor C I to charge or discharge, equal to the transistor 211 pairs
  • the duration of the discharge of the touch capacitor Cx is not described here for the sake of brevity.
  • FIG. 13 is a schematic block diagram of a touch detection apparatus 1300 according to an embodiment of the present application.
  • the touch detection device 1300 can include a circuit 200 for capacitance detection as shown in FIG.
  • the touch detection device 1300 can determine the touch position of the user according to the capacitance of the touch capacitor Cx determined by the circuit 200.
  • the touch detection device 1300 can determine the touch information of the user, such as the touch position of the user on the display screen, according to the capacitance change amount ⁇ C of the touch capacitor Cx relative to the initial capacitance determined by the circuit 200.
  • the embodiment of the present application further provides a terminal device, including the touch detection device 1300 shown in FIG.
  • the terminal device may be a mobile phone, a tablet computer, a notebook computer, a desktop computer, an in-vehicle electronic device, or a wearable smart device.

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Abstract

La présente invention porte sur un circuit (200) de détection de capacité qui présente une résistance aux interférences élevée. Le circuit (200) comprend un premier circuit de charge/décharge (210). Le premier circuit de charge/décharge (210) comprend un transistor monté en grille commune (211). Le transistor (211) est connecté à un condensateur tactile. Le premier circuit de charge/décharge (210) est destiné à vider la charge du condensateur tactile au niveau d'un premier étage, et à charger, au moyen du transistor (211), le condensateur tactile à une tension prédéfinie.
PCT/CN2018/078165 2018-03-06 2018-03-06 Circuit de détection de capacité, dispositif de détection tactile et appareil terminal WO2019169555A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201880000137.3A CN110463041B (zh) 2018-03-06 2018-03-06 用于电容检测的电路、触摸检测装置和终端设备
PCT/CN2018/078165 WO2019169555A1 (fr) 2018-03-06 2018-03-06 Circuit de détection de capacité, dispositif de détection tactile et appareil terminal

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Application Number Priority Date Filing Date Title
PCT/CN2018/078165 WO2019169555A1 (fr) 2018-03-06 2018-03-06 Circuit de détection de capacité, dispositif de détection tactile et appareil terminal

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WO2019169555A1 true WO2019169555A1 (fr) 2019-09-12

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CN112803941A (zh) * 2021-01-07 2021-05-14 深圳锐盟半导体有限公司 触控检测电路和耳机

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CN112505427B (zh) * 2020-11-17 2023-04-07 上海美仁半导体有限公司 电容测量电路及测量方法

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