WO2022233128A1 - 电容触摸检测电路、芯片和电子设备 - Google Patents

电容触摸检测电路、芯片和电子设备 Download PDF

Info

Publication number
WO2022233128A1
WO2022233128A1 PCT/CN2021/134281 CN2021134281W WO2022233128A1 WO 2022233128 A1 WO2022233128 A1 WO 2022233128A1 CN 2021134281 W CN2021134281 W CN 2021134281W WO 2022233128 A1 WO2022233128 A1 WO 2022233128A1
Authority
WO
WIPO (PCT)
Prior art keywords
reference voltage
terminal
capacitive touch
detection circuit
oscillation
Prior art date
Application number
PCT/CN2021/134281
Other languages
English (en)
French (fr)
Inventor
唐亮
张忠
程涛
Original Assignee
上海艾为电子技术股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 上海艾为电子技术股份有限公司 filed Critical 上海艾为电子技术股份有限公司
Publication of WO2022233128A1 publication Critical patent/WO2022233128A1/zh

Links

Images

Classifications

    • 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
    • H03K17/965—Switches controlled by moving an element forming part of the switch
    • H03K17/975—Switches controlled by moving an element forming part of the switch using a capacitive movable element

Definitions

  • the present application relates to the technical field of capacitance detection, and in particular, to a capacitance touch detection circuit, a chip and an electronic device.
  • Capacitive touch keys are widely used non-contact keys, compared to traditional mechanical keys. Capacitive buttons have the advantages of sensitive response, long life and stable performance, so they are widely used in the operation panels of various electronic products.
  • the existing capacitive touch button detection structures mainly include the following: relaxation oscillator capacitance detection, successive approximation capacitance detection, integral differential capacitance detection, and capacitance digital detection. Each structure has its own advantages and disadvantages.
  • the relaxation oscillator capacitance detection structure has been widely used in various electronic products.
  • One of the existing relaxation oscillator detection structures is to use a Schmitt trigger to form an oscillator, and to perform detection by charging and discharging an external capacitor.
  • the Schmitt trigger is used.
  • the device flips, the output is 0, and the external capacitor is discharged; when the discharge reaches the low threshold voltage VTL of the Schmitt trigger, the Schmitt trigger flips again, the output is 1, and the capacitor is recharged; Repeatedly, the Schmitt trigger outputs a square wave signal.
  • the capacitance value of the external capacitor is proportional to the output frequency of the Schmitt trigger.
  • the count value is proportional to the value of the external capacitor.
  • the chip pin is connected to a capacitive touch button. When the hand touches the button, the capacitance value of the touch button will change, so that the count value will change accordingly, so that the touch action can be judged by the difference of the count value.
  • an LDO (Low Dropout Regulator) circuit needs to be added to the capacitance detection circuit to provide a stable power supply.
  • the LDO circuit provides a reference voltage to the oscillator on the one hand, and powers the oscillator itself on the other hand. But adding the LDO circuit increases the power consumption of the entire capacitance detection circuit.
  • the present application provides a capacitive touch detection circuit, a chip and an electronic device to solve the problem of high power consumption of the existing capacitive touch detection circuit.
  • a capacitive touch detection circuit includes: an oscillation module for outputting an oscillation signal;
  • the oscillation module includes: a comparator, a charging and discharging unit, and an oscillation control unit; a first input end of the comparator is connected to a capacitance detection terminal, the second input terminal is connected to a first reference voltage through a first switch, and is connected to a second reference voltage through a second switch, the first reference voltage is greater than the second reference voltage;
  • the oscillation control unit is connected to the output end of the comparator, and is used for outputting an oscillation signal according to the output signal of the comparator, so as to control the on-off state of the first switch and the second switch;
  • the charging and discharging unit is used for A positive feedback charge-discharge control is formed between the output terminal of the comparator and the first input terminal, so that the voltage of the first input terminal of the comparator oscillates between the first reference voltage and the second reference voltage.
  • a reference voltage module connected to the power supply voltage, for converting the power supply voltage and outputting the first reference voltage and the second reference voltage.
  • both the first reference voltage and the second reference voltage are divided voltage values of the power supply voltage, so that the oscillation frequency of the oscillation signal changes with the size of the detected capacitance, and is different from the power supply voltage. size is irrelevant.
  • the reference voltage module includes: a second resistor, a third resistor and a fourth resistor connected in series between the power supply voltage and the ground terminal in sequence; the connection end of the second resistor and the third resistor serves as the first resistor
  • the reference voltage output terminal is used for outputting the first reference voltage; the connection terminal of the third resistor and the fourth resistor is used as a second reference voltage output terminal, which is used for outputting the second reference voltage.
  • the reference voltage module further includes: a first capacitor, one end connected to the first reference voltage output end, and the other end grounded; a second capacitor, one end connected to the second reference voltage output end, the other end ground.
  • a buffer module configured to respectively regulate the first reference voltage and the second reference voltage and then output them.
  • the buffer module includes: a first operational amplifier, a second operational amplifier, a third capacitor and a fourth capacitor; the output end of the first operational amplifier is connected to the negative input end, and is connected to the third capacitor through the third capacitor ground; the positive input terminal of the first operational amplifier is connected to the first reference voltage; the output terminal of the second operational amplifier is connected to the negative input terminal, and is grounded through the fourth capacitor; the second operational amplifier The positive input of the amplifier is connected to the second reference voltage.
  • the oscillation control unit uses the comparator output signal as the first control signal, and outputs a second control signal that is inverse to the first control signal.
  • the oscillation control unit includes: a NAND gate, a first inverter, and a second inverter; one input end of the NAND gate is connected to the output end of the comparator, and the other input end is connected to the output end of the comparator. It is used to input an enable control signal, and the output end of the NAND gate is connected to the first inverter; the output end of the first inverter is used as the output end of the oscillation module to output an oscillation signal, so The oscillating signal is also used as the first control signal; the output end of the first inverter is also connected to the input end of the second inverter, and the output end of the second inverter is used to output the the second control signal.
  • the charging and discharging unit includes: a first resistor connected in series between the output end of the first inverter/comparator output end and the capacitance detection end.
  • the capacitance detection terminal is a solder pad, and the capacitance detection terminal is used for connecting to a sensitivity adjustment capacitor and a sensing electrode plate.
  • both the sensitivity adjustment capacitor and the sensing electrode plate are arranged on a circuit board outside the capacitive touch detection circuit.
  • it further includes: a counting module, connected to the output end of the oscillation module, for counting the oscillation signal.
  • the present application further provides a chip including the capacitive touch detection circuit described in any one of the above.
  • the present application provides an electronic device, including: the capacitive touch detection circuit described in any one of the above.
  • the output frequency of the oscillation module of the above capacitive touch detection circuit of the present application is only related to the charging and discharging resistance of the charging and discharging unit and the capacitance value of the detection terminal, and has nothing to do with the power supply voltage. Therefore, no matter how the power supply voltage changes, the output frequency cycle is stable, and the entire circuit does not need LDO power supply can reduce circuit power consumption.
  • the reference voltage module and buffer module with low-pass filtering function are passed through the power supply voltage to provide an anti-interference reference voltage to the positive input terminal of the comparator, so the anti-interference ability of this circuit is strong.
  • FIG. 1 is a schematic structural diagram of a capacitive touch detection circuit according to an embodiment of the present application
  • FIG. 2 is a schematic structural diagram of a capacitive touch detection circuit according to an embodiment of the present application
  • FIG. 3 is a schematic time sequence diagram of a capacitive touch detection process according to an embodiment of the present application.
  • FIG. 1 is a schematic structural diagram of a capacitive touch detection circuit according to an embodiment of the present invention.
  • the capacitive touch detection circuit includes: an oscillation module 110 and a counting module 120, the oscillation module 110 is configured to output an oscillation signal whose frequency varies with the size of the detection capacitance but is independent of the power supply voltage, and the counting module 120 for counting the oscillating signal.
  • the oscillation module 110 includes a comparator CMP, a charging and discharging unit 112 and an oscillation control unit 111 .
  • the first input terminal of the comparator CMP is connected to the capacitance detection terminal PAD, the second input terminal is connected to the first reference voltage VH through the first switch SA, and is connected to the second reference voltage VL through the second switch SB.
  • the first reference voltage VH is greater than the second reference voltage VL.
  • the first input terminal is a negative input terminal, and the second input terminal is a positive input terminal.
  • the capacitance detection terminal PAD is a bonding pad of the chip where the capacitance touch detection circuit is located, and is used for external connection, and is specifically used for soldering to a circuit board and connecting to a sensing electrode plate on the circuit board.
  • the sensing capacitance C sensor between the sensing electrode plate and the ground changes, and the total capacitance value between the capacitance detection terminal PAD and the ground changes.
  • the induction plate can be a wire on a circuit board.
  • the capacitance detection terminal PAD is further connected to a sensitivity adjustment capacitor Cx for adjusting the sensitivity of the touch detection.
  • the capacitance value of the sensitivity adjustment capacitor Cx is usually 0 to 50 pf.
  • the oscillation control unit 111 is connected to the output end of the comparator CMP, and is configured to output an oscillation control signal according to the output signal of the comparator CMP, so as to control the on-off state of the first switch SA and the second switch SB .
  • the oscillation control unit 111 further includes a control terminal for inputting an enable control signal EN to control the enable state of the oscillation module 110 .
  • the oscillation control signal includes a first control signal DOUT and a second control signal DOUT_B; the first control signal DOUT is used to control the on-off of the first switch SA, the second control signal DOUT_B is used to control the on-off of the second switch SB, the first control signal DOUT and the second control signal DOUT_B are mutually It is an inverted signal, so that at the same time, only one switch of the first switch SA and the second switch SB is turned on.
  • the charging and discharging unit 112 is used to form a positive feedback charging and discharging control between the output terminal of the comparator CMP and the first input terminal, so that the voltage of the first input terminal of the comparator CMP is at the first reference voltage VH. and the second reference voltage VL.
  • the first control signal DOUT output by the oscillation control unit 111 and the output of the comparator CMP are in-phase signals.
  • the charging/discharging unit 112 is connected between the output terminal of the first control signal DOUT and the first input terminal of the comparator CMP. When DOUT is at a high level, the capacitance detection terminal PAD is connected to the ground.
  • the capacitor is charged; when DOUT is low, the capacitor between the capacitor detection terminal PAD and the ground is discharged.
  • the charging and discharging unit 112 may also be connected between the output terminal of the comparator CMP and the first input terminal of the comparator CMP.
  • the comparator CMP output is flipped again; the cycle repeats, so that the PAD terminal voltage oscillates between VL and VH.
  • the comparator CMP outputs a square wave oscillation signal, so that the oscillation control unit 111 outputs a first control signal DOUT with the same frequency as the voltage of the PAD terminal.
  • the first control signal DOUT is also used as an output signal of the oscillation module 110, and the counting module 120 counts the first control signal DOUT.
  • the size of the sensing capacitance C sensor between the capacitance detection terminal PAD and the ground changes, which in turn changes the charging and discharging rate of the PAD terminal, causing the voltage change frequency of the PAD terminal to change, and finally makes the first The frequency of the control signal DOUT changes, and the count value of the counting module 120 changes, so that the touch operation is detected.
  • the frequency of the oscillation signal output by the oscillation module 110 is independent of the power supply voltage, the frequency period of the first control signal DOUT is stable as the power supply voltage supplied by the battery decreases.
  • the whole circuit does not need LDO power supply, which can reduce the power consumption of the circuit.
  • the capacitive touch detection circuit further includes a reference voltage module 130, connected to the power supply voltage VDD, for converting the power supply voltage VDD, and outputting the first reference voltage VH and the second reference voltage VL.
  • a buffer module 140 is further connected between the reference voltage module 130 and the oscillation module 110 , and the buffer module 140 is used to regulate the first reference voltage VH and the second reference voltage VL respectively after voltage regulation. output.
  • the reference voltage module 130 may also be directly connected to the oscillation module 110 .
  • the reference voltage module 130 includes a second resistor R2, a third resistor R3 and a fourth resistor R4 connected in series between the power supply voltage VDD and the ground terminal in sequence;
  • the connection terminal is used as the output terminal of the first reference voltage VH, which is used to output the first reference voltage VH;
  • the connection terminal of the third resistor R3 and the fourth resistor R4 is used as the output terminal of the second reference voltage VL, which is used to output the first reference voltage VH.
  • the second reference voltage VL is used as the output terminal of the first reference voltage VH.
  • the second resistor R2, the third resistor R3 and the fourth resistor R4 are used as voltage dividing resistors, the first reference voltage second reference voltage
  • the first reference voltage VH and the second reference voltage VL can be adjusted by adjusting the sizes of the second resistor R2, the third resistor R3 and the fourth resistor R4.
  • the above-mentioned second resistor R2, third resistor R3 and fourth resistor R4 may be composed of one or more resistors in series and/or parallel respectively, and the second resistor R2, third resistor R3 and fourth resistor R4 are only used as equivalent It is schematic, but not limited to its actual specific structure.
  • the first reference voltage VH and the second reference voltage VL are both the divided voltage values between the power supply voltage VDD and the ground terminal, so the charge and discharge cycle of the capacitance detection terminal PAD is related to the power supply voltage VDD. Therefore, the frequency of the oscillation signal output by the oscillation module 110 can be independent of the power supply voltage VDD.
  • the reference voltage module 130 further includes: a first capacitor C1, one end of which is connected to the output end of the first reference voltage VH, and the other end is grounded; Two capacitors C2, one end is connected to the output end of the second reference voltage VL, and the other end is grounded.
  • the first capacitor C1, the second capacitor C2, the second resistor R2, the third resistor R3 and the fourth resistor R4 form a low-pass filter, which filters out high frequencies for the output first reference voltage VH and the second reference voltage VL. interference.
  • the buffer module 140 includes: a first operational amplifier OP1, a second operational amplifier OP2, a third capacitor C3 and a fourth capacitor C4; the output terminal of the first operational amplifier OP1 is connected to the negative input terminal, and the positive input terminal is connected to the the first reference voltage VH; the output terminal of the second operational amplifier OP2 is connected to the negative input terminal, and the positive input terminal is connected to the second reference voltage VL.
  • a third capacitor C3 is connected in series between the output of the first operational amplifier OP1 and the ground as a capacitive load of the first operational amplifier OP1; a fourth capacitor is connected in series between the output of the second operational amplifier OP2 and the ground C4, as the capacitive load of the second operational amplifier OP2.
  • the buffer module 140 composed of the first operational amplifier OP1 , the second operational amplifier OP2 , the third capacitor C3 and the fourth capacitor C4 provides driving capability for the circuit while stabilizing the first reference voltage VH and the second reference voltage VL.
  • the power supply voltage VDD passes through the reference voltage module 130 and the buffer module 140 with low-pass filtering function to provide an anti-interference reference voltage to the positive input terminal of the comparator CMP, so the circuit has strong anti-interference ability.
  • FIG. 2 is a schematic structural diagram of a capacitive touch detection circuit according to an embodiment of the present invention.
  • the charging and discharging unit 112 of the oscillation module 110 includes a first resistor R1.
  • the first resistor R1 may be composed of one or more resistors connected in series and/or in parallel, and the first resistor R1 is only used as an equivalent illustration, and does not limit its actual specific structure.
  • the oscillation control unit 111 further includes: a NAND gate NAND, a first inverter INV1, and a second inverter INV2; one input end of the NAND gate NAND is connected to the output end of the comparator CMP, and the other An input terminal is used to input the enable control signal EN, the output terminal of the NAND gate NAND is connected to the first inverter INV1; the output terminal of the first inverter INV1 is used to output the first control signal DOUT is also used as the output terminal of the oscillation module 110, and the first control signal DOUT is also used as the oscillation signal output by the oscillation module 110; the output terminal of the first inverter INV1 is also connected to the first control signal DOUT.
  • the input terminals of the two inverters INV2 and the output terminals of the second inverter INV2 are used for outputting a second control signal DOUT_B, and the second control signal DOUT_B is an inverted signal of the first control signal DOUT.
  • the PAD is discharged through the first resistor R1 until the voltage is 0, and the counting module 120 does not count.
  • the comparator CMP outputs a square wave
  • the oscillation control unit 111 outputs the same square wave signal DOUT
  • the counting module 120 counts the number of oscillation cycles of DOUT within the specified measurement time as capacitance sampling data.
  • k is the oscillation coefficient, which is related to the charge-discharge resistance R1 and the voltage swing VL-VH .
  • the oscillation count is N,
  • C total is the total capacitance between the PAD terminal and the ground, including the sensing capacitance C sensor and other parasitic capacitances, and the sensitivity adjustment capacitance Cx. Since the change of C total will change the oscillation frequency, when there is a touch, the C sensor becomes larger, which leads to the increase of C total , which leads to the decrease of the oscillation frequency and the decrease of the count value N, so as to judge whether there is a touch operation.
  • the sensitivity can be adjusted by adjusting the size of the inherent parasitic capacitance C ins .
  • the size of the PAD may be 60 ⁇ m*60 ⁇ m.
  • the detection sensitivity can be adjusted by an external sensitivity adjustment capacitor Cx.
  • the oscillation period of the oscillation signal DOUT Since the size of the oscillation period of the oscillation signal DOUT is related to the charging and discharging time of the total capacitance C total , the oscillation period can be deduced according to the charging and discharging time of the total capacitance C total .
  • V(t) is the capacitor plate voltage at time t
  • V 0 is the power supply voltage
  • the voltage on the capacitance detection terminal PAD is from up to The time is the oscillation clock power-on cycle T1, then according to formula (5), it can be deduced:
  • R R2+R3+R4.
  • the time for the voltage on the capacitance detection terminal PAD to drop from VH to VL is the power-off period T2 of the oscillation clock.
  • a complete clock cycle is:
  • the clock oscillation period can be adjusted by adjusting the value of the charging and discharging resistor R1.
  • the output frequency of the oscillation module 110 is only related to the resistance and capacitance values, and has nothing to do with the power supply voltage VDD. So as the battery-powered supply voltage VDD decreases, the output frequency cycle is stable. The whole circuit does not need LDO power supply, which can reduce the power consumption of the circuit.
  • FIG. 3 is a timing diagram of a capacitive touch detection process according to an embodiment of the present invention.
  • PH1, PH2 and PH3 are three stages of the complete process of a detection.
  • PH1 is the detection preparation stage. In this stage, the enable control signal EN of the oscillation control unit 111 is 0, and the oscillation module 110 is in the off state. First open the comparator CMP, make the comparator CMP in a working state, and establish a stable output.
  • PH2 is the capacitance detection stage.
  • the enable control signal EN is 1
  • the oscillation module 110 oscillates and outputs a stable square wave signal DOUT to the counting module 120, and the digital part counts the number N of square waves.
  • the oscillation module 110 is started again, which can prevent the output oscillation signal DOUT from jumping.
  • PH3 is the data processing stage of detection. In this stage, the enable control signal EN remains at 1, but the digital part no longer receives the count value N of the output signal of the oscillation module 110 .
  • the output of the comparator CMP is low, the oscillator EN is 0, the output of the oscillation module 110 is low, and the entire detection process ends.
  • An embodiment of the present invention further provides a chip, in which the capacitive touch detection circuit described in any of the above embodiments is formed.
  • An embodiment of the present invention further provides an electronic device, including the capacitive touch detection circuit described in any of the above embodiments.
  • the detection accuracy of the capacitive touch detection circuit is improved, and the accuracy of touch control on the electronic device can be improved.
  • the electronic device may be a mobile phone, a tablet computer, a notebook computer, a smart door lock and other devices with a touch control function.

Landscapes

  • Electronic Switches (AREA)

Abstract

提供一种电容触摸检测电路、一种芯片及电子设备，电容触摸检测电路包括振荡模块（110），振荡模块（110）包括：比较器（CMP）、充放电单元（112）以及振荡控制单元（111）；比较器（CMP）的第一输入端连接至电容检测端（PAD），第二输入端通过第一开关（SA）连接至第一参考电压（VH），以及通过第二开关（SB）连接至第二参考电压（VL），第一参考电压（VH）大于第二参考电压（VL）；振荡控制单元（111）连接至比较器（CMP）的输出端，用于根据比较器（CMP）的输出信号输出振荡控制信号，以控制第一开关（SA）和第二开关（SB）的通断状态；充放电单元（112）用于在比较器（CMP）的输出端与第一输入端之间形成正反馈充放电控制，使得比较器（CMP）的第一输入端电压在第一参考电压（VH）和第二参考电压（VL）之间振荡；该电路无需LDO供电，能降低功耗。

Description

电容触摸检测电路、芯片和电子设备
本申请要求于2021年05月07日提交中国专利局、申请号为202110497087.8、发明名称为“电容触摸检测电路、芯片和电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电容检测技术领域，具体涉及一种电容触摸检测电路、一种芯片和一种电子设备。
背景技术
电容触摸按键是一种应用广泛的非接触式按键，相比于传统机械式按键。电容按键具有反应灵敏，寿命长，性能稳定等优点，因此其被广泛应用到各种电子产品的操作面板中。
现有的电容触摸按键检测结构主要有以下几种：张弛振荡器电容检测、逐次逼近电容检测、积分微分电容检测、电容数字检测。每种结构都有其各自的优缺点。
张弛振荡器电容检测结构作为其中一种常用的检测结构，在各类电子产品中均得到广泛的应用。现有的张弛振荡器检测结构的其中一种结构是利用施密特触发器形成振荡器，通过对外接电容进行充放电实现检测，具体的，当充电到高阈值电压VTH时，施密特触发器发生翻转，输出为0，并对外接电容进行放电；当放电到施密特触发器的低阈值电压VTL时，施密特触发器再次发生翻转，输出为1，并对电容重新进行充电；依次反复，施密特触发器输出方波信号。外接电容的电容值正比于施密特触发器的输出频率，在一定时间内，对频率进行计数，那么计数值正比于外接电容的值。芯片管脚外接电容触摸按键，当手接触按键后，会引起触摸按键电容值的改变，使得计数值相应的发生变化，从而可以通过计数值差来对触摸动作进行判断。
为了使振荡器的输出频率和电源电压无关，现有技术中大都需要在电容检测电路中加入LDO(Low Dropout Regulator；低压差线性稳压器)电路，以提供稳定的电源。LDO电路一方面给振荡器提供参考电压，另一方面给振荡器本身供电。但是加入LDO电路使得整个电容检测电路的功耗上升。
如何进一步降低张弛振荡器类型的电容检测电路的功耗，是目前亟待解决 的问题。
发明内容
鉴于此，本申请提供一种电容触摸检测电路、一种芯片以及一种电子设备，以解决现有的电容触摸检测电路功耗较大的问题。
本申请提供的一种电容触摸检测电路，包括：振荡模块，用于输出振荡信号；所述振荡模块包括：比较器、充放电单元以及振荡控制单元；所述比较器的第一输入端连接至电容检测端，第二输入端通过第一开关连接至第一参考电压，以及通过第二开关连接至第二参考电压，所述第一参考电压大于所述第二参考电压；所述振荡控制单元连接至所述比较器的输出端，用于根据所述比较器的输出信号输出振荡信号，以控制所述第一开关和第二开关的通断状态；所述充放电单元用于在所述比较器的输出端与第一输入端之间形成正反馈充放电控制，使得所述比较器的第一输入端电压在第一参考电压和第二参考电压之间振荡。
可选的，还包括：参考电压模块，连接至电源电压，用于将电源电压进行转换，输出所述第一参考电压和所述第二参考电压。
可选的，所述第一参考电压和所述第二参考电压均为所述电源电压的分压值，以使所述振荡信号的振荡频率随被检测电容大小变化，而与所述电源电压的大小无关。
可选的，所述参考电压模块包括：顺次串联于电源电压与地端之间的第二电阻、第三电阻以及第四电阻；所述第二电阻和第三电阻的连接端作为第一参考电压输出端，用于输出所述第一参考电压；所述第三电阻和第四电阻的连接端作为第二参考电压输出端，用于输出所述第二参考电压。
可选的，所述参考电压模块还包括：第一电容，一端连接于所述第一参考电压输出端，另一端接地；第二电容，一端连接于所述第二参考电压输出端，另一端接地。
可选的，还包括：缓冲模块，用于对所述第一参考电压和第二参考电压分别进行稳压后输出。
可选的，所述缓冲模块包括：第一运算放大器、第二运算放大器、第三电容和第四电容；所述第一运算放大器的输出端与负输入端连接，并通过所述第 三电容接地；所述第一运算放大器的正输入端连接至所述第一参考电压；所述第二运算放大器的输出端与负输入端连接，并通过所述第四电容接地；所述第二运算放大器的正输入端连接至所述第二参考电压。
可选的，所述振荡控制单元以所述比较器输出信号作为第一控制信号，并输出与所述第一控制信号反相的第二控制信号。
可选的，所述振荡控制单元包括：与非门、第一反相器、第二反相器；所述与非门的一个输入端连接至所述比较器的输出端，另一输入端用于输入使能控制信号，所述与非门的输出端连接至所述第一反相器；所述第一反相器的输出端作为所述振荡模块的输出端，输出振荡信号，所述振荡信号同时作为所述第一控制信号；所述第一反相器的输出端还连接至所述第二反相器的输入端，所述第二反相器输出端用于输出所述第二控制信号。
可选的，所述充放电单元包括：第一电阻，串联于所述第一反相器的输出端/比较器输出端和所述电容检测端之间。
可选的，所述电容检测端为一焊垫，所述电容检测端用于连接至一灵敏度调节电容以及感应极板。
可选的，所述灵敏度调节电容以及感应极板均设置于所述电容触摸检测电路外部的电路板上。
可选的，还包括：计数模块，连接至所述振荡模块的输出端，用于对所述振荡信号进行计数。
本申请还提供一种芯片，包括如上述任一项所述的电容触摸检测电路。
本申请提供一种电子设备，包括：如上述任一项所述的电容触摸检测电路。
本申请上述电容触摸检测电路的振荡模块的输出频率只和充放电单元的充放电电阻和检测端的电容值有关，和电源电压无关，所以无论电源电压如何变化，输出频率周期稳定，整个电路不需要LDO供电，可以降低电路功耗。
进一步，通过电源电压经过具备低通滤波功能的参考电压模块和缓冲模块，提供抗干扰的参考电压给比较器的正输入端，所以此电路的抗干扰能力较强。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所 需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本申请一实施例的电容触摸检测电路的结构示意图；
图2是本申请一实施例的电容触摸检测电路的结构示意图；
图3是本申请一实施例的电容触摸检测过程的时序示意图。
具体实施方式
如背景技术中所述，现有技术中，为了使得振荡器的输出频率和电源电压无关，需要在电路结构中增加LDO电路，导致功耗上升，电子设备的续航能力下降。
下面结合附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本申请一部分实施例，而非全部实施例。基于本申请中的实施例，本领域技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。在不冲突的情况下，下述各个实施例及其技术特征可以相互组合。
请参考图1，为本发明一实施例的电容触摸检测电路的结构示意图。
该实施例中，所述电容触摸检测电路包括：包括振荡模块110和计数模块120，所述振荡模块110用于输出频率随检测电容大小变化但与电源电压无关的振荡信号，所述计数模块120用于对所述振荡信号进行计数。
所述振荡模块110包括：比较器CMP、充放电单元112以及振荡控制单元111。
所述比较器CMP的第一输入端连接至电容检测端PAD，第二输入端通过第一开关SA连接至第一参考电压VH，以及通过第二开关SB连接至第二参考电压VL，所述第一参考电压VH大于所述第二参考电压VL。该实施例中，所述第一输入端为负输入端，第二输入端为正输入端。
所述电容检测端PAD为所述电容触摸检测电路所在芯片的焊垫，用于和外部连接，具体用于焊接至电路板上，连接至电路板上的感应极板。当用户进行触摸操作，导致感应极板与地之间的传感电容C sensor发生变化，就会使得所述 电容检测端PAD与地之间的总的电容值发生变化。所述感应极板可以是电路板上的导线。
该实施例中，所述电容检测端PAD还连接至一灵敏度调节电容Cx，用于调节所述触摸检测的灵敏度。所述灵敏度调节电容Cx的容值通常为0至50pf。
所述振荡控制单元111连接至所述比较器CMP的输出端，用于根据所述比较器CMP的输出信号输出振荡控制信号，以控制所述第一开关SA和第二开关SB的通断状态。所述振荡控制单元111还包括一控制端，用于输入使能控制信号EN，控制所述振荡模块110的使能状态。
具体的，当EN＝1，所述振荡控制单元111使能，跟随所述比较器CMP的输出信号输出振荡控制信号，具体的，所述振荡控制信号包括第一控制信号DOUT和第二控制信号DOUT_B；所述第一控制信号DOUT用于控制第一开关SA的通断，第二控制信号DOUT_B用于控制第二开关SB的通断，所述第一控制信号DOUT和第二控制信号DOUT_B互为反相信号，使得同一时刻，第一开关SA和第二开关SB中仅有一个开关导通。
所述充放电单元112用于在所述比较器CMP的输出端与第一输入端之间形成正反馈的充放电控制，使得所述比较器CMP的第一输入端电压在第一参考电压VH和第二参考电压VL之间振荡。该实施例中，所述振荡控制单元111输出的第一控制信号DOUT与比较器CMP的输出为同相信号。该实施例中，所述充放电单元112连接于第一控制信号DOUT输出端与所述比较器CMP的第一输入端之间，当DOUT为高电平时，对电容检测端PAD与地之间的电容进行充电；当DOUT为低电平时，电容检测端PAD与地之间的电容进行放电。在其他实施例中，所述充放电单元112还可以连接于所述比较器CMP的输出端与所述比较器CMP的第一输入端之间。
在一个实施例中，当EN＝0时，第一控制信号DOUT＝0(低电平)，第二控制信号DOUT_B＝1(高电平)，比较器CMP的第二输入端(正输入端)连接第二参考电压VL；电容检测端PAD通过所述充放电单元112放电至0，计数模块120不计数。当比较器CMP使能，且EN＝1时，电容检测端PAD电压小于VL，比较器CMP输出信号转为高电平，DOUT＝1，DOUT_B＝0，开关SA导通，SB断开，比较器CMP的正输入端连接第一参考电压VH；由于DOUT＝1,充放电单元112对所 述电容检测端PAD充电，使得PAD端电压自VL增大，至VH时，比较器CMP输出信号再次翻转，比较器CMP正输入端切换为第二参考电压VL，PAD端进行放电，当PAD端电压小于VL，比较器CMP输出再次翻转；循环往复，使得PAD端电压在VL和VH之间往复振荡，比较器CMP输出方波振荡信号，进而使得所述振荡控制单元111输出与所述PAD端电压同频的第一控制信号DOUT。所述第一控制信号DOUT还作为所述振荡模块110的输出信号，所述计数模块120对所述第一控制信号DOUT进行计数。
当用户进行触摸操作时，电容检测端PAD与地之间的传感电容C sensor大小发生变化，进而使得PAD端的充放电速率发生变化，使得PAD端的电压变化频率发生变化，最终使得所述第一控制信号DOUT的频率发生变化，计数模块120的计数值发生变化，从而检测出触摸操作。
本实施例中，由于所述振荡模块110输出振荡信号的频率与电源电压无关，所以随着电池供电的电源电压降低，所述第一控制信号DOUT的频率周期稳定。整个电路不需要LDO供电，可以降低电路功耗。
该实施例中，电容触摸检测电路还包括参考电压模块130，连接至电源电压VDD，用于将电源电压VDD进行转换，输出所述第一参考电压VH和所述第二参考电压VL。进一步的，所述参考电压模块130与所述振荡模块110之间还连接有缓冲模块140，所述缓冲模块140用于对所述第一参考电压VH和第二参考电压VL分别进行稳压后输出。在其他实施例中，也可以将所述参考电压模块130直接连接至所述振荡模块110。
该实施例中，参考电压模块130包括顺次串联于电源电压VDD与地端之间的第二电阻R2、第三电阻R3以及第四电阻R4；所述第二电阻R2和第三电阻R3的连接端作为第一参考电压VH输出端，用于输出所述第一参考电压VH；所述第三电阻R3和第四电阻R4的连接端作为第二参考电压VL输出端，用于输出所述第二参考电压VL。所述第二电阻R2、第三电阻R3以及第四电阻R4，作为分压电阻，所述第一参考电压
Figure PCTCN2021134281-appb-000001
第二参考电压
Figure PCTCN2021134281-appb-000002
可以通过调整所述第二电阻R2、第三电阻R3以及第四 电阻R4的大小，调整所述第一参考电压VH和第二参考电压VL。上述第二电阻R2、第三电阻R3以及第四电阻R4可以分别由一个或多个电阻串联和/或并联组成，所述第二电阻R2、第三电阻R3以及第四电阻R4仅作为等效示意，不限定其实际的具体结构。
也即，所述第一参考电压VH和所述第二参考电压VL均为所述电源电压VDD与地端之间的分压值，所以所述电容检测端PAD充放电的周期与电源电压VDD无关，进而可以使得所述振荡模块110输出振荡信号的频率与电源电压VDD无关。
进一步的，为了避免电源电压VDD波动的噪声影响，该实施例中，所述参考电压模块130还包括：第一电容C1，一端连接于所述第一参考电压VH输出端，另一端接地；第二电容C2，一端连接于所述第二参考电压VL输出端，另一端接地。所述第一电容C1、第二电容C2、第二电阻R2、第三电阻R3以及第四电阻R4构成低通滤波器，为输出的第一参考电压VH和第二参考电压VL滤除高频干扰。
所述缓冲模块140包括：第一运算放大器OP1、第二运算放大器OP2、第三电容C3和第四电容C4；所述第一运算放大器OP1的输出端与负输入端连接，正输入端连接至所述第一参考电压VH；所述第二运算放大器OP2的输出端与负输入端连接，正输入端连接至所述第二参考电压VL。且，所述第一运算放大器OP1的输出与地之间串联有第三电容C3，作为第一运算放大器OP1的电容负载；所述第二运算放大器OP2的输出与地之间串联有第四电容C4，作为第二运算放大器OP2的电容负载。第一运算放大器OP1、第二运算放大器OP2、第三电容C3和第四电容C4构成的缓冲模块140为电路提供驱动能力，同时稳定所述第一参考电压VH和第二参考电压VL。
电源电压VDD经过具备低通滤波功能的参考电压模块130和缓冲模块140，提供抗干扰的参考电压给比较器CMP的正输入端，所以此电路的抗干扰能力较强。
请参考图2，为本发明一实施例的电容触摸检测电路的结构示意图。
该实施例中，所述振荡模块110的充放电单元112包括第一电阻R1。所 述第一电阻R1可以由一个或多个电阻串联和/或并联组成，所述第一电阻R1仅作为等效示意，不限定其实际的具体结构。
所述振荡控制单元111进一步包括：与非门NAND、第一反相器INV1、第二反相器INV2；所述与非门NAND的一个输入端连接至所述比较器CMP的输出端，另一输入端用于输入使能控制信号EN，所述与非门NAND的输出端连接至所述第一反相器INV1；所述第一反相器INV1的输出端用于输出第一控制信号DOUT，同时也作为所述振荡模块110的输出端，所述第一控制信号DOUT同时作为所述振荡模块110输出的振荡信号；所述第一反相器INV1的输出端还连接至所述第二反相器INV2的输入端，所述第二反相器INV2输出端用于输出第二控制信号DOUT_B，所述第二控制信号DOUT_B为所述第一控制信号DOUT的反相信号。
EN＝0(低电平)时，所述振荡控制单元111为非启动状态，与非门NAND输出高电平，经过第一反相器INV1后，输出第一控制信号DOUT＝0(低电平)，第二控制信号DOUT_B＝1(高电平)，控制第一开关SA断开，第二开关SB导通，比较器CMP的正输入端连接第二参考电压VL，此时电容检测端PAD通过第一电阻R1放电至电压为0，计数模块120不计数。
EN＝1(高电平)时，振荡控制单元111为启动状态，此时比较器CMP输出高电平，DOUT＝1，DOUT_B＝0，第一开关SA导通，第二开关SB断开，比较器CMP正输入端连接第一参考电压VH；由于DOUT＝1为高电平，对所述电容检测端PAD充电。充电过程中，比较器CMP持续输出为1，当电容检测端PAD电压上升至VH后，比较器CMP输出翻转为0。
当比较器CMP输出翻转为0，DOUT＝0，DOUT_B＝1，电容检测端PAD进入放电过程，比较器CMP正输入端通过第二开关SB连接至第二参考电压VL。放电过程中，比较器CMP持续输出为0，当电容检测端PAD电压下降至VL后，比较器CMP输出翻转为1，返回到充电过程。
如此周而复始，比较器CMP输出方波，通过所述振荡控制单元111输出相同的方波信号DOUT，通过计数模块120，统计DOUT在指定测量时间内的振荡周期数，作为电容采样数据。
由于振荡周期T＝k*C total，k为振荡系数，与充放电电阻R1和电压摆幅VL-VH 相关。测量时间T Meas内，振荡计数为N，
Figure PCTCN2021134281-appb-000003
Figure PCTCN2021134281-appb-000004
C total为PAD端与地之间的总电容，包括传感电容C sensor以及其他寄生电容、以及灵敏度调节电容Cx。由于C total的变化会改变振荡频率，当有触摸时，C sensor变大，导致C total变大，从而导致振荡频率变小，从而计数值N变小，从而据此判断是否有触摸操作。
对上述公式(1)求导，得到：
Figure PCTCN2021134281-appb-000005
Figure PCTCN2021134281-appb-000006
由公式(3)可知，计数值N的变化率
Figure PCTCN2021134281-appb-000007
与总电容C total的变化速率成反比，计数值N的变化率越高，触摸检测的灵敏度越高。由于dN和C total负相关，因此C total中的固有电容越小，dN越大，灵敏度越高。从上述公式中可以得到，计数值N的变化率与C total的变化率成正比。
总电容C total＝C ins+dC total，C ins为电容检测端PAD与地之间的固有寄生电容，dC total是由于触摸造成的电容变化值，dC total＝dC sensor。可以通过调节所述固有寄生电容C ins的大小，调节灵敏度。
在一些实施例中，所述电容检测端PAD与地之间的固有电容C ins通常包括：比较器CMP负输入端口与地之间的寄生电容C PAD，负输入端口处还通常连接有静电释放结构(ESD)，存在寄生电容C ESD，在外接灵敏度调节电容Cx时，总电容C total＝C x+C PAD+C ESD+C sensor，计数值变化率：
Figure PCTCN2021134281-appb-000008
由公式(4)可以看出，PAD寄生电容C PAD、ESD寄生电容C ESD越小，可以提高芯片的灵敏度。并且PAD要与电源VDD和地之间寄生电容最小，这样可以提高抗干扰能力，所以这里需要选用最小尺寸的焊垫作为所述电容检测端 PAD。在一些实施例中，所述PAD的尺寸可以为60μm*60μm。
在电路结构确定的情况下，C ESD和C PAD值固定，在内部寄生电容最小化之后，可以通过外接的灵敏度调节电容Cx调节检测灵敏度，Cx越小灵敏度越大。这样做的好处是给予外部电容调节灵敏度更多的权重。
在通过数字电路对数据处理过程中，以电容变化的百分比
Figure PCTCN2021134281-appb-000009
与触摸阈值作比较，当电容变化超过触摸阈值，则判断发生了触摸操作。以电容变化的百分比进行判断，可以确保测量结果不受测量时间、振荡摆幅、充放电电流等因素的影响，灵敏度只与
Figure PCTCN2021134281-appb-000010
有关。
由于振荡信号DOUT的振荡周期大小和总电容C total的充放电时间相关，因此可以根据总电容C total的充放电时间推导振荡周期。
由电容充电电压公式：
Figure PCTCN2021134281-appb-000011
其中，V(t)为t时刻的电容极板电压，V 0为电源电压，τ＝R1*C total，一般来说灵敏度调节电容Cx远大于内部比较器CMP端口的寄生电容，因此C total≈Cx，所以τ≈R1*Cx。
对上述公式整理得：
Figure PCTCN2021134281-appb-000012
电容检测端PAD上电压从
Figure PCTCN2021134281-appb-000013
上升到
Figure PCTCN2021134281-appb-000014
的时间即振荡时钟上电周期T1,则根据公式(5)，可推导出：
Figure PCTCN2021134281-appb-000015
其中，R＝R2+R3+R4。
电容检测端PAD上电压从VH下降到VL的时间即振荡时钟下电周期T2，
Figure PCTCN2021134281-appb-000016
完整的时钟周期为：
Figure PCTCN2021134281-appb-000017
所以，可通过调节充放电电阻R1的值来调节时钟振荡周期。
由于电容检测端PAD的寄生电容远小于灵敏度调节电容Cx，因此，C total≈Cx。
从上述振荡器周期公式(8)可以看出，振荡模块110输出频率只和电阻和电容值有关，和电源电压VDD无关。所以随着电池供电的电源电压VDD降低，输出频率周期稳定。整个电路不需要LDO供电，可以降低电路功耗。
请参考图3，为本发明一实施例电容触摸检测过程的时序图。
其中，PH1，PH2和PH3为一次检测的完整过程的三个阶段。
PH1为检测准备阶段，此阶段内，振荡控制单元111的使能控制信号EN为0，振荡模块110处于关闭状态。先打开比较器CMP，使比较器CMP处于工作状态，建立稳定的输出。
PH2为电容检测阶段，此阶段内，使能控制信号EN为1，振荡模块110块振荡并输出稳定方波信号DOUT给计数模块120，数字部分计数方波个数N。在比较器CMP稳定之后，再启动振荡模块110，可以防止输出的振荡信号DOUT发生跳变。
PH3为检测的数据处理阶段，此阶段内，使能控制信号EN保持为1，不过数字部分不再接收振荡模块110输出信号的计数值N。
数据处理结束后，比较器CMP输出为低，振荡器EN为0，振荡模块110输出为低电平，整个检测过程结束。
本发明的实施例还提供一种芯片，所述芯片内形成有如上述任一实施例所述的电容触摸检测电路。
本发明的实施例还提供一种电子设备，包括如上述任一实施例所述的电容触摸检测电路。所述电容触摸检测电路的检测精度提高，可以提高对所述电子设备的触摸控制的准确性。所述电子设备可以是具有触摸控制功能的手机、平板电脑、笔记本电脑、智能门锁等设备。
以上所述仅为本申请的实施例，并非因此限制本申请的专利范围，凡是利 用本申请说明书及附图内容所作的等效结构或等效流程变换，例如各实施例之间技术特征的相互结合，或直接或间接运用在其他相关的技术领域，均同理包括在本申请的专利保护范围内。

Claims (15)

  1. 一种电容触摸检测电路，其特征在于，包括：振荡模块，用于输出振荡信号，所述振荡模块包括：
    比较器、充放电单元以及振荡控制单元；
    所述比较器的第一输入端连接至电容检测端，第二输入端通过第一开关连接至第一参考电压，以及通过第二开关连接至第二参考电压，所述第一参考电压大于所述第二参考电压；
    所述振荡控制单元连接至所述比较器的输出端，用于根据所述比较器的输出信号输出振荡控制信号，以控制所述第一开关和第二开关的通断状态；
    所述充放电单元用于在所述比较器的输出端与第一输入端之间形成正反馈充放电控制，使得所述比较器的第一输入端电压在第一参考电压和第二参考电压之间振荡。
  2. 根据权利要求1所述的电容触摸检测电路，其特征在于，还包括：参考电压模块，连接至电源电压，用于将电源电压进行转换，输出所述第一参考电压和所述第二参考电压。
  3. 根据权利要求2所述的电容触摸检测电路，其特征在于，所述第一参考电压和所述第二参考电压均为所述电源电压的分压值，以使所述振荡信号的振荡频率随被检测电容大小变化，而与所述电源电压的大小无关。
  4. 根据权利要求2所述的电容触摸检测电路，其特征在于，所述参考电压模块包括：顺次串联于电源电压与地端之间的第二电阻、第三电阻以及第四电阻；所述第二电阻和第三电阻的连接端作为第一参考电压输出端，用于输出所述第一参考电压；所述第三电阻和第四电阻的连接端作为第二参考电压输出端，用于输出所述第二参考电压。
  5. 根据权利要求4所述的电容触摸检测电路，其特征在于，所述参考电压模块还包括：第一电容，一端连接于所述第一参考电压输出端，另一端接地；第二电容，一端连接于所述第二参考电压输出端，另一端接地。
  6. 根据权利要求1所述的电容触摸检测电路，其特征在于，还包括：缓冲模块，用于对所述第一参考电压和第二参考电压分别进行稳压后输出。
  7. 根据权利要求6所述的电容触摸检测电路，其特征在于，所述缓冲 模块包括：第一运算放大器、第二运算放大器、第三电容和第四电容；所述第一运算放大器的输出端与负输入端连接，并通过所述第三电容接地；所述第一运算放大器的正输入端连接至所述第一参考电压；所述第二运算放大器的输出端与负输入端连接，并通过所述第四电容接地；所述第二运算放大器的正输入端连接至所述第二参考电压。
  8. 根据权利要求1所述的电容触摸检测电路，其特征在于，所述振荡控制单元以所述比较器输出信号作为第一控制信号，并输出与所述第一控制信号反相的第二控制信号。
  9. 根据权利要求8所述的电容触摸检测电路，其特征在于，所述振荡控制单元包括：与非门、第一反相器、第二反相器；所述与非门的一个输入端连接至所述比较器的输出端，另一输入端用于输入使能控制信号，所述与非门的输出端连接至所述第一反相器；所述第一反相器的输出端作为所述振荡模块的输出端，输出振荡信号，所述振荡信号同时作为所述第一控制信号；所述第一反相器的输出端还连接至所述第二反相器的输入端，所述第二反相器输出端用于输出所述第二控制信号。
  10. 根据权利要求1所述的电容触摸检测电路，其特征在于，所述充放电单元包括：第一电阻，串联于所述第一反相器的输出端/比较器输出端和所述电容检测端之间。
  11. 根据权利要求1所述的电容触摸检测电路，其特征在于，所述电容检测端为一焊垫，所述电容检测端用于连接至一灵敏度调节电容以及感应极板。
  12. 根据权利要求11所述的电容触摸检测电路，其特征在于，所述灵敏度调节电容以及感应极板均设置于所述电容触摸检测电路外部的电路板上。
  13. 根据权利要求1所述的电容触摸检测电路，其特征在于，还包括：计数模块，连接至所述振荡模块的输出端，用于对所述振荡信号进行计数。
  14. 一种芯片，其特征在于，包括如权利要求1至13中任一项所述的电容触摸检测电路。
  15. 一种电子设备，其特征在于，包括：如权利要求1至13中任一项所述的电容触摸检测电路。
PCT/CN2021/134281 2021-05-07 2021-11-30 电容触摸检测电路、芯片和电子设备 WO2022233128A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202110497087.8A CN113258916A (zh) 2021-05-07 2021-05-07 电容触摸检测电路、芯片和电子设备
CN202110497087.8 2021-05-07

Publications (1)

Publication Number Publication Date
WO2022233128A1 true WO2022233128A1 (zh) 2022-11-10

Family

ID=77223880

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/134281 WO2022233128A1 (zh) 2021-05-07 2021-11-30 电容触摸检测电路、芯片和电子设备

Country Status (2)

Country Link
CN (1) CN113258916A (zh)
WO (1) WO2022233128A1 (zh)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113777537A (zh) * 2021-08-30 2021-12-10 上海芯凌微电子有限公司 一种检测芯片引脚电容正确接入的电路及方法
CN114323361B (zh) * 2021-12-30 2024-06-04 成都动芯微电子有限公司 一种传感器电容检测电路及其方法
CN116131836B (zh) * 2022-12-26 2024-04-09 深圳市航顺芯片技术研发有限公司 一种触摸按键低功耗并联装置及方法
CN116719384B (zh) * 2023-08-07 2023-12-15 深圳市思远半导体有限公司 检测控制电路和开关电路

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080048772A1 (en) * 2006-07-26 2008-02-28 Rohm Co., Ltd. Sensor Circuit, Semiconductor Device, and Electronic Apparatus
CN105591633A (zh) * 2014-09-30 2016-05-18 精工半导体有限公司 振荡电路
CN109586689A (zh) * 2018-11-19 2019-04-05 珠海格力电器股份有限公司 一种振荡器及其芯片
CN111092609A (zh) * 2019-12-30 2020-05-01 西北工业大学 一种无参考电压的rc张弛振荡器

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8106715B1 (en) * 2009-12-04 2012-01-31 Qualcomm Atheros, Inc. Low-power oscillator
US10312887B2 (en) * 2016-11-30 2019-06-04 Omnivision Technologies, Inc. Self-biasing integrated oscillator without bandgap reference
CN107681994B (zh) * 2017-09-23 2020-11-17 深圳大学 一种振荡器电路
KR101986799B1 (ko) * 2017-12-27 2019-06-07 주식회사 하이빅스 저전력과 작은 면적으로 구현한 단일 비교기 구조의 릴렉세이션 발진기
CN111490755B (zh) * 2020-04-20 2023-08-18 成都华微电子科技股份有限公司 张弛振荡器电路

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080048772A1 (en) * 2006-07-26 2008-02-28 Rohm Co., Ltd. Sensor Circuit, Semiconductor Device, and Electronic Apparatus
CN105591633A (zh) * 2014-09-30 2016-05-18 精工半导体有限公司 振荡电路
CN109586689A (zh) * 2018-11-19 2019-04-05 珠海格力电器股份有限公司 一种振荡器及其芯片
CN111092609A (zh) * 2019-12-30 2020-05-01 西北工业大学 一种无参考电压的rc张弛振荡器

Also Published As

Publication number Publication date
CN113258916A (zh) 2021-08-13

Similar Documents

Publication Publication Date Title
WO2022233128A1 (zh) 电容触摸检测电路、芯片和电子设备
US8797049B2 (en) Low power capacitive touch detector
US8729913B2 (en) Capacitance sensing systems, circuits and methods that include current conveyor based oscillators
US8261619B2 (en) Time to digital converting circuit and pressure sensing device using the same
US8040143B2 (en) Capacitance sensing with mismatch compensation
CN102968224B (zh) 触控面板的控制电路及控制方法
CN111801584B (zh) 电容检测电路、触控装置和终端设备
WO2017114514A1 (zh) 积分电路及电容感测电路
CN109560804A (zh) 一种触摸按键控制方法、控制电路、芯片
CN108777574B (zh) 一种电容触摸按键电路
WO2022155888A1 (zh) 一种rc张弛振荡器
WO2017197574A1 (zh) 电容检测的装置
US6710629B2 (en) Impedance comparison integrator circuit
US8232847B2 (en) Oscillation circuit
WO2006133594A1 (en) Circuit and process for power management
WO2024119710A1 (zh) 光传感器读出电路以及芯片
US8878556B2 (en) Sensing device and method
CN116203411A (zh) 一种应用于mcu中触摸按键电容检测方法及其系统
JPH085590A (ja) 湿度センサ
KR100653403B1 (ko) 정전용량변화 검출방법 및 검출집적회로
US11281314B2 (en) Methods and apparatus for variable capacitance detection
TWI737216B (zh) 自電容檢測電路以及具有該電容檢測電路的資訊處理裝置
JPH10132872A (ja) 低電圧感知回路
CN206627188U (zh) 一种压电谐振式微质量测量系统
CN117741257A (zh) 电容检测电路、检测方法、检测装置以及检测设备

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21939773

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21939773

Country of ref document: EP

Kind code of ref document: A1