WO2021016991A1 - 电容检测电路、触控芯片及电子设备 - Google Patents

电容检测电路、触控芯片及电子设备 Download PDF

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Publication number
WO2021016991A1
WO2021016991A1 PCT/CN2019/098897 CN2019098897W WO2021016991A1 WO 2021016991 A1 WO2021016991 A1 WO 2021016991A1 CN 2019098897 W CN2019098897 W CN 2019098897W WO 2021016991 A1 WO2021016991 A1 WO 2021016991A1
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WO
WIPO (PCT)
Prior art keywords
cancellation
branch
detection capacitor
module
control
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PCT/CN2019/098897
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English (en)
French (fr)
Inventor
袁广凯
蒋宏
唐智
沈海明
Original Assignee
深圳市汇顶科技股份有限公司
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Application filed by 深圳市汇顶科技股份有限公司 filed Critical 深圳市汇顶科技股份有限公司
Priority to PCT/CN2019/098897 priority Critical patent/WO2021016991A1/zh
Priority to EP19917526.6A priority patent/EP3798808B1/en
Priority to CN201980001389.2A priority patent/CN112602046B/zh
Priority to US17/009,763 priority patent/US11326907B2/en
Publication of WO2021016991A1 publication Critical patent/WO2021016991A1/zh

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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
    • H03K17/96—Touch switches
    • H03K17/962—Capacitive touch switches
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/24—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
    • 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
    • G06F3/0416—Control or interface arrangements specially adapted for digitisers
    • G06F3/04166—Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving
    • 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
    • G06F3/0416—Control or interface arrangements specially adapted for digitisers
    • G06F3/0418—Control or interface arrangements specially adapted for digitisers for error correction or compensation, e.g. based on parallax, calibration or alignment
    • G06F3/04182—Filtering of noise external to the device and not generated by digitiser components
    • 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
    • G06F3/0416—Control or interface arrangements specially adapted for digitisers
    • G06F3/0418—Control or interface arrangements specially adapted for digitisers for error correction or compensation, e.g. based on parallax, calibration or alignment
    • G06F3/04186—Touch location disambiguation
    • 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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
    • H03K2217/94—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated
    • H03K2217/96—Touch switches
    • H03K2217/9607—Capacitive touch switches
    • H03K2217/96071—Capacitive touch switches characterised by the detection principle
    • H03K2217/960725—Charge-transfer

Definitions

  • the embodiments of the present application relate to the technical field of capacitance detection, and in particular to a capacitance detection circuit, a touch chip and an electronic device.
  • the principle is that a capacitance is formed between the detection electrode and the system ground, which is called self-capacitance detection.
  • the capacitance formed between the detection electrode and the system ground has a basic capacitance or an initial capacitance.
  • the capacitance between the detection electrode and the system ground will increase. By detecting the change in the capacitance, the user's related touch operation can be judged.
  • the prior art has the disadvantage of low self-capacitance detection sensitivity, which ultimately leads to low accuracy of self-capacitance detection.
  • one of the technical problems solved by the embodiments of the present application is to provide a capacitance detection circuit, a touch chip and an electronic device to overcome the above-mentioned defects in the prior art.
  • the embodiment of the present application provides a capacitance detection circuit, which includes: a control module, a drive module, a cancellation module, and a charge transfer module.
  • the drive module is configured to detect a pair of detections through a first charging branch under the control of the control module.
  • the capacitor is charged in the forward direction, or the detection capacitor is charged in the reverse direction through the second charging branch;
  • the cancellation module is used to perform the detection capacitance on the detection capacitor through the first cancellation branch under the control of the control module
  • the offset processing of the basic capacitance, or, under the control of the control module, the detection capacitor is subjected to the offset processing of the basic capacitance through the second offset branch;
  • the charge transfer module is used to perform the offset processing on the detection capacitor The charge is transferred to generate an output voltage.
  • the drive module includes at least two switch units, and the at least two switch units switch the switch states under the control of the control module to form the The first charging branch or the second charging branch.
  • the switch unit is a single-pole single-throw switch unit
  • the control module is further configured to control one of the single-pole single-throw switch units to form a switch when it is closed.
  • the first charging branch or, controlling another single-pole single-throw switch unit to form the second charging branch when it is closed.
  • the switch unit is a single-pole double-throw switch unit
  • the control module is further configured to control the single-pole double-throw switch unit to switch between different contacts. Switch to form the first charging branch or the second charging branch.
  • the detection capacitor is connected to a forward voltage source through the first charging branch, so that the first charging branch positively charges the detection capacitor
  • the detection capacitor is electrically connected to a negative voltage source through the second charging branch, so that the second charging branch reversely charges the detection capacitor.
  • the cancellation module includes at least two switch units, and the at least two switch units switch their switch states under the control of the control module to form the The first cancellation branch or the second cancellation branch.
  • the switch unit is a single-pole single-throw switch unit
  • the control module is further configured to control one of the single-pole single-throw switch units to form a switch when it is closed.
  • the first cancellation branch or the second cancellation branch is formed when another single-pole single-throw switch unit is controlled to be closed.
  • the switch unit is a single-pole double-throw switch unit
  • the control module is further configured to control the single-pole double-throw switch unit to switch between different contacts. Switch to form the first cancellation branch or the second cancellation branch.
  • the cancellation module is connected to a negative voltage source through one end of the first cancellation branch, so that the first cancellation branch performs the detection capacitance on the detection capacitance.
  • Basic capacitance cancellation processing the cancellation module is connected to a forward voltage source through one end of the second cancellation branch, so that the second cancellation branch performs the basic capacitance cancellation processing on the detection capacitor.
  • the cancellation module includes a first cancellation resistance and a second cancellation resistance, and the cancellation module performs a first cancellation branch on the basic electricity of the detection capacitance.
  • the detection capacitor is in the first discharge state through the first cancellation resistor; when the cancellation module performs the cancellation processing on the basic capacitance of the detection capacitor through the second cancellation branch, the detection capacitor passes The second cancellation resistance is in the second discharge state.
  • the resistance value of the first cancellation resistor is not equal to the resistance value of the second cancellation resistor.
  • the detection capacitor after the detection capacitor is positively charged through the first charging branch, the detection capacitor is subjected to the offset processing of the basic capacitance through the first cancellation branch. Or, after the detection capacitor is reverse-charged through the second charging branch, the detection capacitor is subjected to the offset processing of the basic capacitance through the second cancellation branch.
  • the charge transfer module includes a differential amplifier circuit, the inverting end of the differential amplifier circuit is electrically connected with a common mode voltage, and the positive terminal of the differential amplifier circuit The phase terminal is electrically connected to the detection capacitor, so that charge transfer processing is performed on the detection capacitor; or the positive phase terminal of the differential amplifier circuit is electrically disconnected from the detection capacitor, so that the detection capacitor is charged Treatment or offset treatment.
  • a driving module if the number of detection capacitors is multiple, a driving module, a cancellation module, and a charge transfer module can be configured for each detection capacitance.
  • the embodiment of the present application provides a capacitance detection method, which includes:
  • the driving module performs forward charging of the detection capacitor through the first charging branch under the control of the control module, or reversely charges the detection capacitor through the second charging branch;
  • the cancellation module performs basic capacitance cancellation processing on the detection capacitor through the first cancellation branch under the control of the control module, or, under the control of the control module, performs the cancellation processing on the detection capacitor through the second cancellation branch. Performing offset processing of the basic electric capacity;
  • the charge transfer module transfers the charge of the detection capacitor to generate an output voltage.
  • the driving module includes at least two switch units, and correspondingly, further includes: the at least two switch units are switched under the control of the control module The switch state is to form the first charging branch or the second charging branch.
  • the switch unit is a single-pole single-throw switch unit, and the at least two switch units switch their switch states under the control of the control module to form the
  • the first charging branch or the second charging branch includes: the control module controls one of the single-pole single-throw switch units to be closed to form the first charging branch, or the control module controls another One of the single-pole single-throw switch units is closed to form the second charging branch.
  • the switch unit is a single-pole double-throw switch unit
  • the method further includes: the control module controls the single-pole double-throw switch unit to switch between different contacts. Switch between points to form the first charging branch or the second charging branch.
  • the detection capacitor when the detection capacitor is forwardly charged through the first charging branch, the detection capacitor is connected to the forward voltage source through the first charging branch.
  • the detection capacitor when the detection capacitor is reversely charged through the second charging branch, the detection capacitor is electrically connected to a negative voltage source through the second charging branch.
  • the cancellation module includes at least two switch units, and correspondingly, further includes: the at least two switch units switch under the control of the control module Switch state to form the first cancellation branch or the second cancellation branch.
  • the switch unit is a single-pole single-throw switch unit.
  • the at least two switch units switch their switch states under the control of the control module to Forming the first cancellation branch or the second cancellation branch includes: the control module controls one of the single-pole single-throw switch units to form the first cancellation branch when one of the single-pole single-throw switch units is closed, or controls the other one The second cancellation branch is formed when the single-pole single-throw switch unit is closed.
  • the switch unit is a single-pole double-throw switch unit
  • the method further includes: the control module controls the single-pole double-throw switch unit to switch between different contacts. Switch between points to form the first cancellation branch or the second cancellation branch.
  • the cancellation module when the basic capacitance of the detection capacitor is cancelled by the first cancellation branch, the cancellation module passes through one end of the first cancellation branch. Connected to the negative voltage source; when the detection capacitor is subjected to the cancellation processing of the basic capacitance through the second cancellation branch, the cancellation module is connected to the positive voltage source through one end of the second cancellation branch.
  • the cancellation module includes a first cancellation resistance and a second cancellation resistance, and the cancellation module performs a first cancellation branch on the basic electricity of the detection capacitance.
  • the detection capacitor is in the first discharge state through the first cancellation resistor; when the cancellation module performs the cancellation processing on the basic capacitance of the detection capacitor through the second cancellation branch, the detection capacitor passes The second cancellation resistance is in the second discharge state.
  • the detection capacitor after the detection capacitor is forwardly charged through the first charging branch, the detection capacitor is subjected to the offset processing of the basic capacitance through the first cancellation branch. Or, after the detection capacitor is reverse-charged through the second charging branch, the detection capacitor is subjected to the offset processing of the basic capacitance through the second cancellation branch.
  • the resistance value of the first cancellation resistor is not equal to the resistance value of the second cancellation resistor.
  • the charge transfer module includes a differential amplifier circuit, the inverting end of the differential amplifier circuit is electrically connected with a common mode voltage, and the positive terminal of the differential amplifier circuit The phase terminal is electrically connected to the detection capacitor when performing charge transfer processing on the detection capacitor, and the positive phase terminal of the differential amplifier circuit is disconnected from the detection capacitor when the detection capacitor is charged and canceled. Electric connection.
  • a driving module if the number of detection capacitors is multiple, a driving module, a cancellation module, and a charge transfer module can be configured for each detection capacitor.
  • An embodiment of the application provides a touch control chip, including: the capacitance detection circuit described in any embodiment of the application.
  • An embodiment of the application provides an electronic device, which includes the touch chip described in any embodiment of the application.
  • the capacitance detection circuit includes: a control module, a drive module, a cancellation module, and a charge transfer module
  • the drive module is used to pass the first charging support under the control of the control module
  • the detection capacitor is charged forward through the second charging branch, or the detection capacitor is reversely charged through the second charging branch
  • the cancellation module is used to charge the detection capacitor through the first cancellation branch under the control of the control module.
  • the detection capacitor performs the offset processing of the basic capacitance, or, under the control of the control module, the detection capacitor performs the offset processing of the basic capacitance through the second offset branch; the charge transfer module is used to The charge of the detection capacitor is transferred to generate an output voltage; the output voltage can be used to determine the capacitance change before and after the detection capacitor is affected by an external electric field.
  • the charge transfer module is used to The charge of the detection capacitor is transferred to generate an output voltage; the output voltage can be used to determine the capacitance change before and after the detection capacitor is affected by an external electric field.
  • it can be eliminated or reduced by charge cancellation.
  • the influence of the basic capacitance of the small detected detection capacitance increases the rate of change of the capacitance, improves the sensitivity of the self-capacitance detection, and ultimately improves the accuracy of the self-capacitance detection under the condition that the capacitance change is unchanged.
  • FIG. 1A is a schematic structural diagram of a capacitance detection circuit in Embodiment 1 of the application;
  • FIG. 1B is a schematic diagram of the working sequence of the capacitance detection circuit in the first embodiment of the application.
  • FIG. 1C is a schematic flowchart of a capacitance detection method in Embodiment 1 of this application;
  • FIG. 2A is a schematic structural diagram of a capacitance detection circuit in Embodiment 2 of this application;
  • 2B is a schematic diagram of the working sequence of the capacitance detection circuit in the second embodiment of the application.
  • FIG. 3A is a schematic structural diagram of a capacitance detection circuit according to Embodiment 3 of the application.
  • FIG. 3B is a schematic diagram of a sequence of capacitance detection according to Embodiment 3 of the application.
  • FIG. 5 is an exemplary structure diagram of the offset resistance in the fifth embodiment of the application.
  • the capacitance detection circuit since the capacitance detection circuit includes a control module, a drive module, a cancellation module, and a charge transfer module, the drive module is used to pass the first charging support under the control of the control module.
  • the detection capacitor is charged forward through the second charging branch, or the detection capacitor is reversely charged through the second charging branch; the cancellation module is used to charge the detection capacitor through the first cancellation branch under the control of the control module.
  • the detection capacitor performs the offset processing of the basic capacitance, or, under the control of the control module, the detection capacitor performs the offset processing of the basic capacitance through the second offset branch; the charge transfer module is used to The charge of the detection capacitor is transferred to generate an output voltage; the output voltage can be used to determine the capacitance change before and after the detection capacitor is affected by an external electric field.
  • the basic capacitance of the small detected detection capacitance increases the capacitance change rate under the condition that the capacitance change is unchanged, improves the sensitivity of self-capacitance detection, and finally improves the accuracy of self-capacitance detection.
  • the self-capacitance detection of one detection capacitor is taken as an example for description. Therefore, in the following embodiments, correspondingly, the number of driving modules and canceling modules is one each. In fact, by extension, from a technical point of view, if there are multiple detection capacitors, multiple drive modules and cancellation modules can be configured correspondingly, or for one detection capacitor, one drive module and cancellation Module.
  • the driving module may include at least one switch and a voltage source configured to form the first charging branch and the second charging branch
  • the cancellation module may include at least one switch and correspondingly
  • the first cancellation branch and the second cancellation branch are configured with voltage sources.
  • the realization of the drive module and the cancellation module by configuring the switch and the voltage source is only an example, and those of ordinary skill in the art can also Use any other drive module that can realize the formation of the first charging branch and the second charging branch, and any other cancellation module that can realize the formation of the first cancellation electric branch and the second cancellation branch.
  • the driving module may include at least two switch units, and the at least two switch units switch the switch states under the control of the control module to form the first charging branch or the The second charging branch eliminates low-frequency noise in the circuit and improves the signal-to-noise ratio.
  • the driving module includes two switch units as an example for description.
  • the switch unit is specifically a single-pole single-throw switch unit
  • the control module is further configured to control the formation of the first charging branch when one of the single-pole single-throw switch units is closed, or , Controlling another single-pole single-throw switch unit to form the second charging branch when it is closed.
  • the detection capacitor when the detection capacitor is positively charged through the first charging branch, the detection capacitor is connected to the forward voltage source through the first charging branch; When the detection capacitor is reversely charged, the detection capacitor is electrically connected to a negative voltage source through the second charging branch.
  • the cancellation module may include at least two switch units, and the at least two switch units switch switch states under the control of the control module to form the first cancellation branch or the The second offset branch.
  • the driving module includes two switch units as an example for description.
  • the switch unit is a single-pole single-throw switch unit
  • the control module is further configured to control one of the single-pole single-throw switch units to form the first cancellation branch when one of the single-pole single-throw switch units is closed, or, When the other single-pole single-throw switch unit is controlled to be closed, the second cancellation branch is formed.
  • the cancellation module when the basic capacitance of the detection capacitor is cancelled by the first cancellation branch, the cancellation module is connected to a negative voltage source through one end of the first cancellation branch;
  • the cancellation module When the second cancellation branch performs the cancellation processing of the basic capacitance of the detection capacitor, the cancellation module is connected to a forward voltage source through one end of the second cancellation branch.
  • the cancellation module includes a first cancellation resistance and a second cancellation resistance, and when the cancellation module performs cancellation processing on the basic capacitance of the detection capacitor through the first cancellation branch, the detection The capacitor is in the first discharge state through the first cancellation resistance; when the cancellation module performs the cancellation process on the basic capacitance of the detection capacitor through the second cancellation branch, the detection capacitor is in the second discharge state through the second cancellation resistance .
  • the resistance value of the first cancellation resistor and the resistance value of the second cancellation resistor are not equal.
  • the detection capacitor is subjected to a basic capacitance cancellation process through the first cancellation branch; or, through the second charging branch After the detection capacitor is reversely charged, the detection capacitor is subjected to a cancellation process of the basic capacitance through the two cancellation branches.
  • the charge transfer module includes a differential amplifying circuit, the inverting end of the differential amplifying circuit is electrically connected with a common mode voltage, and the non-inverting end of the differential amplifying circuit is performing the detection capacitor During the charge transfer process, it is electrically connected to the detection capacitor, and the positive phase end of the differential amplifier circuit is electrically disconnected from the detection capacitor when the detection capacitor is charged and canceled.
  • the two switching units specifically included in the driving module 110 are respectively denoted K 11 and K 12 , the positive voltage source is denoted as Vcc, the negative voltage source is denoted as Vss, and the switch unit K 11.
  • the switch unit K 12 is a single-pole single-throw switch unit.
  • the two switching units specifically included in the cancellation module 120 are respectively denoted as K 21 and K 22 , the positive voltage source is denoted as Vcc, and the negative voltage source is denoted as Vss.
  • the cancellation module 120 also includes two cancellation resistors, denoted as R 1 and R 2 respectively .
  • the transfer module is denoted as 130, which includes a differential amplifier, a feedback resistor Rf, and a feedback capacitor Cf to realize the conversion of the charge on the detection capacitor into a voltage signal.
  • the output voltage of the transfer module 130 is respectively filtered by an anti-alias filter (AAF) 140, then sent to an analog-digital converter (Analog-Digital Converter, ADC) 150 for sampling, and then passes through a digital signal processor (DIGITAL SIGNAL PROCESSOR, referred to as DSP) performs quadrature (IQ) demodulation, and the obtained raw data is sent to the CPU for coordinate calculation to obtain the touch position.
  • AAF anti-alias filter
  • ADC Analog-Digital Converter
  • DSP digital signal processor
  • IQ quadrature
  • control module is denoted as 160
  • control signals that control the switch unit K 11 , the switch unit K 12 , the switch unit K 21 , the switch unit K 22 , and the switch unit K 3 are respectively denoted as ⁇ 1, ⁇ 4, ⁇ 2, ⁇ 5, and ⁇ 3.
  • FIG. 1A is a schematic diagram of the structure of the capacitance detection circuit in Embodiment 1 of the application
  • FIG. 1B is a schematic diagram of the working sequence of the capacitance detection circuit in Embodiment 1 of the application. It should be noted here that, in FIG. 1B, when the capacitance of the detection capacitor changes due to an external electric field, and at the same time a perfect cancellation is achieved, the output voltage of the charge transfer module is Vout.
  • Period t1 Specifically, in FIG. 1A, when the detection capacitor is forwardly charged through the first charging branch, the detection capacitor is connected to the forward voltage source Vcc through the first charging branch;
  • the charging branch is specifically: the control module generates a control signal ⁇ 1 to control the switch unit K 11 to close, so that the detection capacitor Cx is connected to the forward voltage source Vcc, thereby forming a first charge in which the forward voltage source Vcc charges the detection capacitor Cx Branch circuit, the voltage reaches Vcc after charging.
  • the other switching units except for the switching unit K 11 are turned off under the control of their respective control signals.
  • Period t2 After the detection capacitor is charged through the first charging branch, the switch unit K 11 is turned off, and the switch unit K 21 is closed under the control of its control signal ⁇ 2 to form the first cancellation branch, and the detection capacitor passes through the resistor R 1 (i.e. the first offset resistance) forward discharge to the voltage source Vss (i.e. the first discharge state) to offset the basic capacitance of the detection capacitor. After the discharge is completed, the voltage of the detection capacitor to the system ground In addition, in the t2 period, the other switching units except for the switching unit K 21 are turned off under the control of their respective control signals.
  • the cancellation module when the cancellation module performs cancellation processing on the basic capacitance of the detection capacitor through the first cancellation branch, the detection capacitor is in the first discharge state through the first cancellation resistor.
  • Time period t3 After the basic capacitance of the detection capacitor is cancelled by the first cancellation branch, the switch unit K 3 is closed under the control of its control signal ⁇ 3. In addition, the other switch units are opened and the detection capacitance The charge is transferred to the charge transfer module so that the charge transfer module generates an output voltage Vout, and the amount of charge transferred from the detection capacitor Cx to the charge transfer module is [u(t2)-Vcm]*Cx.
  • Period t4 After completing the charge transfer process in the period t3, the switch unit K 11 , the switch unit K 21 , and the switch unit K 22 are turned off under the control of their respective control signals, but the switch unit K 12 is controlled by its control signal ⁇ 4 Next closed. Since the switch unit K 12 is closed, thereby forming a second charging branch to the detection capacitor is charged, so that the detection is reversely charged capacitor to Vss.
  • Period t5 After the detection capacitor is charged through the second charging branch, the switch unit K 11 , the switch unit K 21 , and the switch unit K 12 are turned off under the control of their respective control signals, but the switch unit K 22 is in its control signal It is closed under the control of ⁇ 5, so that a second cancellation branch is formed, and the detection capacitor is reversely discharged to the voltage source Vcc (ie, the second discharge state) through the resistor R 2 (ie, the second cancellation resistance). Ground voltage
  • Time period t6 After the basic capacitance of the detection capacitor is cancelled by the second cancellation branch, the switch unit K 3 is closed under the control of its control signal ⁇ 5, and the other switch units are opened under the control of their respective control signals.
  • the detection capacitor transfers charges to the charge transfer module, so that the charge transfer module generates an output voltage Vout, and the amount of charge transferred from the detection capacitor Cx to the charge transfer module is [u(t5)-Vcm]*Cx.
  • the resistance value of the first cancellation resistor is set not equal to the resistance value of the second cancellation resistor. Since the charging and discharging speeds of the circuit are not the same, by setting the size of the first cancellation resistance to be different from the size of the second cancellation resistance, the voltage on the detection capacitor is exactly Vcm when there is no touch operation, thereby achieving perfect cancellation. To improve the sensitivity of touch detection.
  • t1 and t4 are charging phases
  • t2 and t5 are offset phases
  • t3 and t6 are charge transfer phases
  • t1 to t6 are a detection period T.
  • the t4 to t6 process is actually the inverse process of t1 to t3, thereby weakening the highly correlated noise in the two process circuits, especially the low frequency noise.
  • the charge transfer module includes a differential amplifier circuit (such as a double-ended differential amplifier), the inverting end of the differential amplifier circuit is electrically connected with a common mode voltage Vcm, and the noninverting end of the differential amplifier circuit is at When performing charge transfer processing on the detection capacitor, it is electrically connected to the detection capacitor to realize the charge transfer of the detection capacitor to the charge transfer module.
  • the positive phase end of the differential amplifier circuit charges and cancels the detection capacitor. Disconnect the electrical connection with the detection capacitor during processing.
  • FIG. 1C is a schematic flow chart of the capacitance detection method in Embodiment 1 of the application; for the capacitance detection circuit shown in FIG. 1A, in one detection period, the corresponding capacitance detection method includes:
  • the embodiment of the present application provides a capacitance detection method, which includes:
  • the driving module performs forward charging of the detection capacitor through the first charging branch under the control of the control module;
  • the switching unit K 11 in a closed state under the control of the control module to form the first charging branch.
  • the detection capacitor When the detection capacitor is positively charged through the first charging branch in step S101, the detection capacitor is connected to the forward voltage source Vcc through the first charging branch.
  • the cancellation module performs a basic capacitance cancellation process on the detection capacitor through the first cancellation branch under the control of the control module.
  • the cancellation module includes at least two switch units, and correspondingly, the control module controls one of the switch units K 21 to form the first cancellation branch when one of the switch units K 21 is closed.
  • step S102 when the basic capacitance of the detection capacitor is cancelled by the first cancellation branch, the cancellation module is connected to the negative voltage source Vss through one end of the first cancellation branch.
  • the charge transfer module performs transfer processing on the charge of the detection capacitor to generate an output voltage
  • the switching element K 3 is closed in Figure 1A, other switching means in the OFF state, transferred to the charge transfer module generated on the output voltage Vout detected capacitance.
  • S104 The driving module reversely charges the detection capacitor through the second charging branch under the control of the control module;
  • the switch unit K 12 is in a closed state under the control of the control module to form the second charging branch.
  • the detection capacitor when the detection capacitor is reversely charged through the second charging branch, the detection capacitor is electrically connected to the negative voltage source Vss through the second charging branch.
  • the cancellation module performs the cancellation process of the basic capacitance on the detection capacitor through the second cancellation branch under the control of the control module;
  • the cancellation module includes at least two switch units, and correspondingly, the control module controls one of the switch units K 22 to form the second cancellation branch when one of the switch units K 22 is closed.
  • step S105 when the basic capacitance of the detection capacitor is cancelled by the second cancellation branch, the cancellation module is connected to the forward voltage source Vcc through one end of the second cancellation branch.
  • the charge transfer module performs transfer processing on the charge of the detection capacitor to generate an output voltage.
  • the switching element K 3 is closed in Figure 1A, other switching means in the OFF state, transferred to the charge transfer capacitance detection module.
  • the size of R1 is set to be not equal to the size of R2. Since the circuit charging and discharging speeds are different, the size of R1 is not equal to the size of R2, so that when there is no touch operation, the detection The voltage on the capacitor is exactly Vcm, so as to achieve perfect cancellation to improve the sensitivity of touch detection.
  • t1 and t4 to t6 are symmetrical processes
  • t1 and t4, t3 and t6 will be set to be the same, so it is expected that the values of t2 and t5 are also the same or close.
  • the operating frequency of the circuit first determine the target values of t2 and t5, and then determine the calculated values of the resistors R1 and R2 according to the values of Vcc, Vss, Vcm and the estimated value of Cx. Due to the limited offset resistance of the actual chip, the set value of R1 and R2 will deviate from the calculated value.
  • the set value of R1 and R2 can only be as close as possible to the calculated value, so when determining the setting of R1 and R2 After the value is set, fine-tune the length of time t2 and t5, so that the actual value of t2 and t5 are equal or as close as possible, so that both the positive and negative processes can reach or close to the state of perfect cancellation. Then the gain of the amplifying circuit can be adjusted to increase the sensitivity of touch detection.
  • FIG. 2A is a schematic diagram of the structure of the capacitance detection circuit in the second embodiment of the application
  • FIG. 2B is a schematic diagram of the working sequence of the capacitance detection circuit in the second embodiment of the application.
  • the structure of the drive module the same as the above embodiment is that one of the switch units K 11 is a single-pole single-throw switch unit, and the other switch unit K 12 is a single-pole double-throw switch unit to form the first charging branch or The second charging branch.
  • a switch unit K 23 is added to the above-mentioned switch units K 21 and K 22.
  • the switch unit K 23 is a single-pole double-throw switch unit to cooperate with the switch units K 21 and K 22 Achieve the formation of the first offset branch or the second offset branch.
  • the control signals of the switch unit K 11 , switch unit K 12 , switch unit K 21 , switch unit K 22 , switch unit K 23 , and switch unit K 4 are control signals ⁇ 1, ⁇ 5, ⁇ 2, ⁇ 3, ⁇ 5, ⁇ 4.
  • the reference signs of the control signals are the same as those in the first embodiment, it does not mean that they are essentially the same control signals as the control signals in the first embodiment.
  • the switch unit K 11 is closed under the control of the control signal ⁇ 1, and the switch unit K 12 contacts the contact 1 under the control of the control signal ⁇ 5 to form the first charging branch.
  • the switch unit K 23 is in the control signal ⁇ 5 Contact 1 is touched down, but because the switch unit K 21 is disconnected under the control of the control signal ⁇ 2, the cancellation module does not work.
  • the switch unit K 11 is opened under the control of the control signal ⁇ 1
  • the switch unit K 21 is closed under the control of the control signal ⁇ 2
  • the switch unit K 22 is opened under the control of the control signal ⁇ 3, thereby forming a first offset Branch, after the end of the t2 period, the voltage of the detection capacitor is u(t2);
  • the switch unit K 3 is closed under the control of the control signal ⁇ 4, the switch units K 11 , K 21 , and K 21 are disconnected under the control of their respective control signals, and the charge on the detection capacitor is transferred to the charge transfer processing module.
  • the amount of charge is [u(t2)-Vcm]*Cx.
  • the switch unit K 11 is closed under the control of the control signal ⁇ 1, and the switch unit K 12 contacts the contact 2 under the control of the control signal ⁇ 5 to form a second charging branch.
  • the switch unit K 23 is in the control signal ⁇ 5
  • the contact 2 is touched downward, but since the switch unit K 21 is disconnected under the control of the control signal ⁇ 2, the cancellation module does not work.
  • the switch unit K 11 is turned off under the control of the control signal ⁇ 1, the switch unit K 23 contacts the contact 2 under the control of the control signal ⁇ 5, the switch unit K 22 is closed under the control of the control signal ⁇ 3, and the switch unit K 21 is disconnected under the control of the control signal ⁇ 2, thereby forming a second cancellation branch.
  • the voltage of the detection capacitor is u(t5);
  • the switch unit K 3 is closed under the control of the control signal ⁇ 4, the switch units K 11 , K 21 , and K 21 are disconnected under the control of their respective control signals, and the charge on the detection capacitor is transferred to the charge transfer processing module.
  • the amount of charge is [u(t5)-Vcm]*Cx.
  • the size of R1 is set to be unequal to the size of R2. Since the charging and discharging speed of the circuit is different, the size of R1 is not equal to the size of R2, so that when there is no touch operation, the detection capacitor The voltage on it is exactly Vcm, so as to achieve perfect cancellation to improve the sensitivity of touch detection.
  • t1 and t4 are charging phases
  • t2 and t5 are offset phases
  • t3 and t6 are charge transfer phases
  • t1 to t6 are a detection period T.
  • the t4 to t6 process is actually the inverse process of t1 to t3, thereby weakening the highly correlated noise in the two process circuits, especially the low frequency noise.
  • the output voltage of the charge transfer module is 0.
  • the output voltage of the charge transfer module is not 0.
  • the output voltage of the amplifier is completely generated by the touch, and a larger magnification can be used to increase the amplitude of the output voltage to facilitate detection, thereby improving the touch sensitivity.
  • t1 and t4 to t6 are symmetrical processes
  • t1 and t4, t3 and t6 will be set to be the same, so it is expected that the values of t2 and t5 are also the same or close.
  • the operating frequency of the circuit first determine the target values of t2 and t5, and then determine the calculated values of the resistors R1 and R2 according to the values of Vcc, Vss, Vcm and the estimated value of Cx.
  • the set value of R1 and R2 will deviate from the calculated value. In fact, it can only be as close as possible to the calculated value.
  • the gain of the amplifying circuit can be adjusted to increase the sensitivity of touch detection.
  • the method for implementing capacitance detection by the capacitance detection circuit shown in FIG. 2A is similar to the foregoing embodiment shown in FIG. 1A.
  • each detection capacitor can be configured with a driving module, a cancellation module, and a charge transfer module.
  • the charge transfer module includes a differential amplifier circuit
  • the similar characteristics between adjacent detection channels when detecting the capacitance change of the detection capacitor can be realized through the differential principle, thereby achieving noise suppression and ultimately improving the signal-to-noise ratio .
  • the following is an example of processing two detection capacitors (denoted as Cx1 and Cx2, respectively).
  • FIG. 3A is a schematic diagram of the structure of the three-capacitance detection circuit in the embodiment of the application
  • FIG. 3B is a schematic diagram of the timing of the three-capacitance detection in the embodiment of the application; as shown in FIG.
  • the module 120 is different from the foregoing embodiment in that, in the charge transfer processing stage, the detection capacitors Cx1 and Cx2 are respectively connected to the differential amplifier in the charge transfer processing 130, and in fact, charges are transferred to the charge transfer processing module at the same time.
  • the cancellation resistances in one cancellation module 120 are R1 and R2
  • the cancellation resistances in the other cancellation module 120 are R3 and R4.
  • the output Vout of the amplifying circuit is a negative voltage
  • the amplifying circuit outputs Vout as a positive voltage.
  • This embodiment charges, cancels, and transfers two adjacent detection capacitors at the same time, and outputs the amplified signal to the subsequent circuit through a differential amplifier.
  • adjacent detection channels often have similar basic capacitances, similar temperature drifts when temperature changes, and similar noise characteristics. Therefore, this embodiment can suppress noise, improve the signal-to-noise ratio, and has the ability to suppress temperature drift.
  • the capacitance change of the detection capacitance of the two detection capacitances is relatively large, and then according to the relative magnitude relationship of the capacitance, To further determine the location of the touch.
  • Fig. 4 is an exemplary structure diagram of the control circuit in the fourth embodiment of the application; as shown in Fig. 4, it includes several counters (for example, if there are five, they are recorded as counter1, counter2, counter3, counter4, and counter5), The output of each counter controls the switch unit in the first or second embodiment above, that is, the above-mentioned control signal ⁇ 1- ⁇ 5 is formed.
  • These counters share the same clock signal sys-clk to obtain the same clock accuracy.
  • the higher the clock frequency the higher the time control accuracy that can be obtained. Therefore, the clock signal generally uses the main clock of the touch detection system, and its main frequency is the highest in the entire system.
  • Each counter also has its own data line connected to the corresponding register, and the counting cycle and action time of these counters are modified by modifying the value of the register, so as to achieve the effect of controlling the working sequence of the switch.
  • Fig. 5 is an exemplary structure diagram of the offset resistance in the fifth embodiment of the application; as shown in Fig. 5, it mainly includes a plurality of resistors (Res1...Resn) and a plurality of switches (SW1...SWn). Each resistor is connected in parallel with a switch to form a combination, and several such combinations are connected in series. Each switch has a control line, and the control lines of all switches are connected to the register together. By modifying the value of the register Code[n:0], different switches can be turned on and off, thereby controlling the resistance value of the offset resistor.
  • the second cancellation branch One end of the second cancellation resistor in the circuit is directly connected to the voltage source Vcc, and the other end is connected to the switch unit K 22 , so that the two cancellation circuits are independent of each other.
  • the first cancellation resistance in the first cancellation branch is arranged between the switch units K 21 and K 23 , and the first cancellation resistance can be connected to the voltage source Vss through the switch unit K 21 ;
  • the second cancellation resistance in the cancellation branch is arranged between the switch units K 22 and K 23.
  • the second cancellation resistance can be connected to the voltage source Vcc through the switch unit K 22 ; and the switch unit K 23 is connected to the contact 1 and the contact 2 Switching to form the first cancellation branch and the second cancellation branch respectively.
  • the various voltage sources used in the above embodiments may be generated by a voltage source generating module according to requirements.
  • An embodiment of the present application also provides an electronic device, which includes the touch chip described in any one of the embodiments of the present application.
  • the detectable output voltage is increased, thereby increasing the signal-to-noise ratio.
  • each switch unit of a single switch is taken as an example for description, in fact, it can also be implemented in the form of a circuit combination structure, where the constituent elements can be any electronic switch with on-off function.
  • the components can form a charging branch and a cancellation branch, and can switch from the charging branch to the cancellation branch, and make the detection circuit enter the charge transfer state.
  • the electronic devices in the embodiments of this application exist in various forms, including but not limited to:
  • Mobile communication equipment This type of equipment is characterized by mobile communication functions, and its main goal is to provide voice and data communications.
  • Such terminals include: smart phones (such as iPhone), multimedia phones, functional phones, and low-end phones.
  • Ultra-mobile personal computer equipment This type of equipment belongs to the category of personal computers, has calculation and processing functions, and generally also has mobile Internet features.
  • Such terminals include: PDA, MID and UMPC devices, such as iPad.
  • Portable entertainment equipment This type of equipment can display and play multimedia content.
  • Such devices include: audio, video players (such as iPod), handheld game consoles, e-books, as well as smart toys and portable car navigation devices.
  • Server A device that provides computing services.
  • the structure of a server includes a processor, hard disk, memory, system bus, etc.
  • the server is similar to a general-purpose computer architecture, but because it needs to provide highly reliable services, it is in terms of processing capacity and stability. , Reliability, security, scalability, and manageability.

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Abstract

一种电容检测电路、触控芯片及电子设备，电容检测电路，其包括：控制模块、驱动模块、抵消模块以及电荷转移模块，所述驱动模块用于在所述控制模块的控制下通过第一充电支路对检测电容进行正向充电，或者，通过第二充电支路对所述检测电容进行反向充电；所述抵消模块用于在所述控制模块的控制下通过第一抵消支路对所述检测电容进行基础电容量的抵消处理，或者，在所述控制模块的控制下通过第二抵消支路对所述检测电容进行所述基础电容量的抵消处理；所述电荷转移模块用于对所述检测电容的电荷进行转移处理以生成输出电压。该电容检测电路提高了自电容检测的灵敏度，最终提高了自电容检测的准确度。

Description

电容检测电路、触控芯片及电子设备 技术领域
本申请实施例涉及电容检测技术领域，尤其涉及一种电容检测电路、触控芯片及电子设备。
背景技术
对自电容检测来说，其原理是检测电极与***地之间会形成电容，称之为自电容检测，检测电极与***地之间形成的电容具有基础电容量或初始电容量。当手指靠近或触摸检测电极时，检测电极和***地之间的电容量会变大，通过检测该电容的变化量，可以判断用户的相关触控操作。
在电容触控领域，柔性屏是一个重要的发展方向。当利用上述自电容原理实现电容触控检测时，由于柔性屏往往比传统电容触控屏更薄，导致检测电极相对于***地距离更近，因而该电容的基础电容量显著高于传统电容触控屏的该电容的基础电容量。另外，由于使用细金属线网格(metal-mesh)作为检测电极，感应面积相对较小，当有手指触控时，导致该电容变化量较小。较小的电容变化量意味着需要较高的电路增益，以使检测电路能够检测到触摸时电容变化量产生的电信号，但是由于基础电容量远高于电容变化量，如果采用较高的电路增益又容易导致检测电路饱和。
另外，电容的变化量较小由此导致产生的电信号也很小，容易被电路噪声淹没而无法检测到。由此可见，现有技术存在自电容检测灵敏度低，最终导致自电容检测的准确度较低的缺陷。
发明内容
有鉴于此，本申请实施例所解决的技术问题之一在于提供一种电容检测电路、触控芯片及电子设备，用以克服现有技术中上述缺陷。
本申请实施例提供了一种电容检测电路，其包括：控制模块、驱动模块、抵消模块以及电荷转移模块，所述驱动模块用于在所述控制模块的控制下通过第一充电支路对检测电容进行正向充电，或者，通过第二充电支路对所述检测电容进行反向充电；所述抵消模块用于在所述控制模块的控制下通过第一抵消支路对所述检测电容进行基础电容量的抵消处理，或者，在所述控制模块的控制下通过第二抵消支路对所述检测电容进行所述基础电容量的抵消处理；所述电荷转移模块用于对所述检测电容的 电荷进行转移处理以生成输出电压。
可选地，在本申请的任一电容检测电路实施例中，所述驱动模块包括至少两个开关单元，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一充电支路或者所述第二充电支路。
可选地，在本申请的任一电容检测电路实施例中，所述开关单元为单刀单掷开关单元，所述控制模块进一步用于控制其中一个所述单刀单掷开关单元处于闭合时形成所述第一充电支路，或者，控制另外一个所述单刀单掷开关单元处于闭合时形成所述第二充电支路。
可选地，在本申请的任一电容检测电路实施例中，所述开关单元为单刀双掷开关单元，所述控制模块进一步用于控制所述单刀双掷开关单元在不同的触点之间切换以形成述第一充电支路或者第二充电支路。
可选地，在本申请的任一电容检测电路实施例中，所述检测电容通过所述第一充电支路连接到正向电压源，以使第一充电支路对检测电容进行正向充电；所述检测电容通过所述第二充电支路电连接到负向电压源，以使第二充电支路对所述检测电容进行反向充电。
可选地，在本申请的任一电容检测电路实施例中，所述抵消模块包括至少两个开关单元，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一抵消支路或者所述第二抵消支路。
可选地，在本申请的任一电容检测电路实施例中，所述开关单元为单刀单掷开关单元，所述控制模块进一步用于控制其中一个所述单刀单掷开关单元处于闭合时形成所述第一抵消支路，或者，控制另外一个所述单刀单掷开关单元处于闭合时形成所述第二抵消支路。
可选地，在本申请的任一电容检测电路实施例中，所述开关单元为单刀双掷开关单元，所述控制模块进一步用于控制所述单刀双掷开关单元在不同的触点之间切换以形成述第一抵消支路或者第二抵消支路。
可选地，在本申请的任一电容检测电路实施例中，所述抵消模块通过所述第一抵消支路一端连接到负向电压源，以使第一抵消支路对所述检测电容进行基础电容量的抵消处理；所述抵消模块通过所述第二抵消支路一端连接到正向电压源，以使第二抵消支路对所述检测电容进行基础电容量的抵消处理。
可选地，在本申请的任一电容检测电路实施例中，所述抵消模块包括第一抵消电阻和第二抵消电阻，所述抵消模块通过第一抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第一抵消电阻处于第一放电状态；所述抵消模块通过第二抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通 过第二抵消电阻处于第二放电状态。
可选地，在本申请的任一电容检测电路实施例中，第一抵消电阻的阻值与第二抵消电阻的阻值不相等。
可选地，在本申请的任一电容检测电路实施例中，通过第一充电支路对检测电容进行正向充电之后，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理；或者，通过第二充电支路对检测电容进行反向充电之后，通过二抵消支路对所述检测电容进行基础电容量的抵消处理。
可选地，在本申请的任一电容检测电路实施例中，所述电荷转移模块包括差分放大电路，所述差分放大电路的反相端电连接有共模电压，所述差分放大电路的正相端与所述检测电容电连接，以使在所述检测电容进行电荷转移处理；或者所述差分放大电路的正相端与所述检测电容断开电连接，以使所述检测电容进行充电处理或者抵消处理。
可选地，在本申请的任一电容检测电路实施例中，若所述检测电容的数量为多个，则可对每个所述检测电容配置一个驱动模块、抵消模块以及电荷转移模块。
本申请实施例提供一种电容检测方法，其包括：
驱动模块在控制模块的控制下通过第一充电支路对检测电容进行正向充电，或者，通过第二充电支路对所述检测电容进行反向充电；
抵消模块在所述控制模块的控制下通过第一抵消支路对所述检测电容进行基础电容量的抵消处理，或者，在所述控制模块的控制下通过第二抵消支路对所述检测电容进行所述基础电容量的抵消处理；
电荷转移模块对所述检测电容的电荷进行转移处理以生成输出电压。
可选地，在本申请的任一电容检测方法实施例中，所述驱动模块包括至少两个开关单元，对应地，还包括：所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一充电支路或者所述第二充电支路。
可选地，在本申请的任一电容检测方法实施例中，所述开关单元为单刀单掷开关单元，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一充电支路或者所述第二充电支路，包括：所述控制模块控制其中一个所述单刀单掷开关单元处于闭合以形成所述第一充电支路，或者，所述控制模块控制另外一个所述单刀单掷开关单元处于闭合以形成所述第二充电支路。
可选地，在本申请的任一电容检测方法实施例中，所述开关单元为单刀双掷开关单元，对应地，还包括：所述控制模块控制所述单刀双掷开关单元在不同的触点之间切换以形成述第一充电支路或者第二充电支路。
可选地，在本申请的任一电容检测方法实施例中，通过第一充电支路对检测 电容进行正向充电时，所述检测电容通过所述第一充电支路连接到正向电压源；通过第二充电支路对所述检测电容进行反向充电时，所述检测电容通过所述第二充电支路电连接到负向电压源。
可选地，在本申请的任一电容检测方法实施例中，所述抵消模块包括至少两个开关单元，对应地，还包括：所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一抵消支路或者所述第二抵消支路。
可选地，在本申请的任一电容检测方法实施例中，所述开关单元为单刀单掷开关单元，对应地，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一抵消支路或者所述第二抵消支路，包括：所述控制模块控制其中一个所述单刀单掷开关单元处于闭合时形成所述第一抵消支路，或者，控制另外一个所述单刀单掷开关单元处于闭合时形成所述第二抵消支路。
可选地，在本申请的任一电容检测方法实施例中，所述开关单元为单刀双掷开关单元，对应地，还包括：所述控制模块控制所述单刀双掷开关单元在不同的触点之间切换以形成述第一抵消支路或者第二抵消支路。
可选地，在本申请的任一电容检测方法实施例中，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第一抵消支路一端连接到负向电压源；通过第二抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第二抵消支路一端连接到正向电压源。
可选地，在本申请的任一电容检测方法实施例中，所述抵消模块包括第一抵消电阻和第二抵消电阻，所述抵消模块通过第一抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第一抵消电阻处于第一放电状态；所述抵消模块通过第二抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第二抵消电阻处于第二放电状态。
可选地，在本申请的任一电容检测方法实施例中，通过第一充电支路对检测电容进行正向充电之后，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理；或者，通过第二充电支路对检测电容进行反向充电之后，通过二抵消支路对所述检测电容进行基础电容量的抵消处理。
可选地，在本申请的任一电容检测方法实施例中，第一抵消电阻的阻值与第二抵消电阻的阻值不相等。
可选地，在本申请的任一电容检测方法实施例中，所述电荷转移模块包括差分放大电路，所述差分放大电路的反相端电连接有共模电压，所述差分放大电路的正相端在对所述检测电容进行电荷转移处理时与所述检测电容电连接，所述差分放大电路的正相端在对所述检测电容进行充电处理以及抵消处理时与所述检测电容断开电连 接。
可选地，在本申请的任一电容检测方法实施例中，若所述检测电容的数量为多个，则可对每个所述检测电容配置一个驱动模块、抵消模块以及电荷转移模块。
本申请实施例提供一种触控芯片，包括：本申请任一实施例中所述的电容检测电路。
本申请实施例提供一种电子设备，其包括本申请任一实施例中所述的触控芯片。
本申请实施例提供的技术方案中，由于电容检测电路，其包括：控制模块、驱动模块、抵消模块以及电荷转移模块，所述驱动模块用于在所述控制模块的控制下通过第一充电支路对检测电容进行正向充电，或者，通过第二充电支路对所述检测电容进行反向充电；所述抵消模块用于在所述控制模块的控制下通过第一抵消支路对所述检测电容进行基础电容量的抵消处理，或者，在所述控制模块的控制下通过第二抵消支路对所述检测电容进行所述基础电容量的抵消处理；所述电荷转移模块用于对所述检测电容的电荷进行转移处理以生成输出电压；所述输出电压可用于确定所述检测电容被外加电场影响前后的电容变化量，当应用于自电容检测时，由于通过电荷抵消可消除或者减小检测到的检测电容的基础电容量的影响，在电容变化量不变的情况下，增加了电容的变化率，提高了自电容检测的灵敏度，最终提高了自电容检测的准确度。
附图说明
后文将参照附图以示例性而非限制性的方式详细描述本申请实施例的一些具体实施例。附图中相同的附图标记标示了相同或类似的部件或部分。本领域技术人员应该理解，这些附图未必是按比例绘制的。附图中：
图1A为本申请实施例一中电容检测电路的结构示意图；
图1B为本申请实施例一中电容检测电路工作时序示意图。
图1C为本申请实施例一中电容检测方法的流程示意图；
图2A为本申请实施例二中电容检测电路的结构示意图；
图2B为本申请实施例二中电容检测电路工作时序示意图；
图3A为本申请实施例三电容检测电路的结构示意图；
图3B为本申请实施例三电容检测的时序示意图；
图4为本申请实施例四中控制电路的示例性结构图；
图5为本申请实施例五中抵消电阻的示例性结构图。
具体实施方式
实施本申请实施例的任一技术方案必不一定需要同时达到以上的所有优点。
本申请实施例提供的下述技术方案中，由于电容检测电路包括：控制模块、驱动模块、抵消模块以及电荷转移模块，所述驱动模块用于在所述控制模块的控制下通过第一充电支路对检测电容进行正向充电，或者，通过第二充电支路对所述检测电容进行反向充电；所述抵消模块用于在所述控制模块的控制下通过第一抵消支路对所述检测电容进行基础电容量的抵消处理，或者，在所述控制模块的控制下通过第二抵消支路对所述检测电容进行所述基础电容量的抵消处理；所述电荷转移模块用于对所述检测电容的电荷进行转移处理以生成输出电压；所述输出电压可用于确定所述检测电容被外加电场影响前后的电容变化量，当应用于自电容检测时，由于通过电荷抵消可消除或者减小检测到的检测电容的基础电容量，在电容变化量不变的情况下，增加了电容的变化率，提高了自电容检测的灵敏度，最终提高了自电容检测的准确度。
下面结合本申请实施例附图进一步说明本申请实施例具体实现。
下述实施例一和二中，以实现对一个检测电容进行自电容检测为例进行说明，因此，下述实施例中，对应地，驱动模块和抵消模块的数量各为一个。实际上，推而广之，从技术思想来看，若有多个检测电容，则可对应配置多个驱动模块和抵消模块，或者又称为对于一个检测电容来说，配置一个驱动模块和抵消模块。
可选地，在实施时，驱动模块可以包括至少一个开关以及对应地为形成第一充电支路以及第二充电支路而配置的电压源，以及抵消模块可以包括至少一个开关以及对应地为形成第一抵消支路以及第二抵消支路而配置的电压源，但是，需要说明的是，通过配置开关以及电压源的方式来实现驱动模块和抵消模块仅仅是示例，本领域普通技术人员也可以使用其他任意可实现形成第一充电支路、第二充电支路的驱动模块，以及其他任意可实现形成第一抵消电支路、第二抵消支路的抵消模块。
可选地，在实施时，所述驱动模块可以包括至少两个开关单元，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一充电支路或者所述第二充电支路，从而消除电路中的低频噪声，提高信噪比。下述实施例中，以驱动模块包括两个开关单元为例进行说明。
可选地，在实施时，所述开关单元具体为单刀单掷开关单元，所述控制模块进一步用于控制其中一个所述单刀单掷开关单元处于闭合时形成所述第一充电支路，或者，控制另外一个所述单刀单掷开关单元处于闭合时形成所述第二充电支路。
可选地，在实施时，通过第一充电支路对检测电容进行正向充电时，所述检测电容通过所述第一充电支路连接到正向电压源；通过第二充电支路对所述检测电容进行反向充电时，所述检测电容通过所述第二充电支路电连接到负向电压源。
可选地，在实施时，所述抵消模块可以包括至少两个开关单元，所述至少两 个开关单元在所述控制模块的控制下切换开关状态以形成所述第一抵消支路或者所述第二抵消支路。下述实施例中，以驱动模块包括两个开关单元为例进行说明。
可选地，在实施时，所述开关单元为单刀单掷开关单元，所述控制模块进一步用于控制其中一个所述单刀单掷开关单元处于闭合时形成所述第一抵消支路，或者，控制另外一个所述单刀单掷开关单元处于闭合时形成所述第二抵消支路。
可选地，在实施时，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第一抵消支路一端连接到负向电压源；通过第二抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第二抵消支路一端连接到正向电压源。
可选地，在实施时，所述抵消模块包括第一抵消电阻和第二抵消电阻，所述抵消模块通过第一抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第一抵消电阻处于第一放电状态；所述抵消模块通过第二抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第二抵消电阻处于第二放电状态。
可选地，所述第一抵消电阻的阻值和第二抵消电阻的的阻值不相等。
可选地，在实施时，通过第一充电支路对检测电容进行正向充电之后，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理；或者，通过第二充电支路对检测电容进行反向充电之后，通过二抵消支路对所述检测电容进行基础电容量的抵消处理。
可选地，在实施时，所述电荷转移模块包括差分放大电路，所述差分放大电路的反相端电连接有共模电压，所述差分放大电路的正相端在对所述检测电容进行电荷转移处理时与所述检测电容电连接，所述差分放大电路的正相端在对所述检测电容进行充电处理以及抵消处理时与所述检测电容断开电连接。
具体到下述实施例一和实施例二，驱动模块110具体包括的两个开关单元分别记为K 11、K 12、正向电压源记为Vcc、负向电压源记为Vss，开关单元K 11、开关单元K 12均为单刀单掷开关单元。抵消模块120具体包括的两个开关单元分别记为K 21、K 22、正向电压源记为Vcc、负向电压源记为Vss。抵消模块120还包括2个抵消电阻，分别记为R 1、R 2。另外，转移模块记为130，其包括差分放大器、反馈电阻Rf、反馈电容Cf，以实现将检测电容上的电荷转化为电压信号。转移模块130的输出电压分别经抗混叠滤波器(Anti-alias Filter，简称AAF)140滤波后，送入模数转换器(Analog-Digital Converter，简称ADC)150采样，然后经过数字信号处理器(DIGITAL SIGNAL PROCESSOR，简称DSP)进行正交(IQ)解调，得到的原始数据送至CPU进行坐标计算，以获得触摸的位置。另外，控制模块记为160，其控制开关单元K 11、开关单元 K 12、开关单元K 21、开关单元K 22、开关单元K 3的控制信号分别记为Φ1、Φ4、Φ2、Φ5、Φ3。
图1A为本申请实施例一中电容检测电路的结构示意图；图1B为本申请实施例一中电容检测电路工作时序示意图。此处需要说明的是，图1B中，当存在外加电场而导致检测电容的电容量发生变化，与此同时实现完美抵消时，电荷转移模块的输出电压时Vout。
t1时段:具体地，在图1A中，通过第一充电支路对检测电容进行正向充电时，所述检测电容通过所述第一充电支路连接到正向电压源Vcc；所述第一充电支路具体为：控制模块生成控制信号Φ1以控制开关单元K 11闭合，使得检测电容Cx连接到正向电压源Vcc，从而形成正向电压源Vcc对检测电容Cx进行充电处理的第一充电支路，充电完成后电压达到Vcc。另外，在t1时段，除开关单元K 11之外的其他开关单元在各自控制信号的控制下断开。
t2时段:在通过第一充电支路完成对检测电容的充电之后，开关单元K 11断开，开关单元K 21在其控制信号Φ2的控制下闭合形成第一抵消支路，检测电容通过电阻R 1(即第一抵消电阻)向电压源Vss正向放电(即第一放电状态)以对检测电容的基础电容量进行抵消处理，完成放电之后，检测电容对***地的电压
Figure PCTCN2019098897-appb-000001
另外，在t2时段，除开关单元K 21之外的其他开关单元在各自控制信号的控制下断开。
由图1A可见，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第一抵消支路一端连接到负向电压源Vss。
可选地，在本实施例中，所述抵消模块通过第一抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第一抵消电阻处于第一放电状态。
t3时段:在完成通过第一抵消支路对检测电容的基础电容量进行抵消处理之后，开关单元K 3在其控制信号Φ3的控制下闭合，除此之外，其他开关单元断开，检测电容向电荷转移模块转移电荷，使得电荷转移模块生成输出电压Vout，检测电容Cx向电荷转移模块转移的电荷量为[u(t2)-Vcm]*Cx。
t4时段:在完成t3时段的上述电荷转移处理之后，开关单元K 11、开关单元K 21、开关单元K 22在各自控制信号的控制下断开，但开关单元K 12在其控制信号Φ4的控制下闭合。由于开关单元K 12闭合，从而形成第二充电支路以对检测电容进行充电，使得检测电容被反向充电至Vss。
t5时段:在完成通过第二充电支路对检测电容充电之后，开关单元K 11、开关单元K 21、开关单元K 12在各自控制信号的控制下断开，但开关单元K 22在其控制信号Φ5的控制下闭合，使得形成第二抵消支路，检测电容通过电阻R 2(即第二抵消电阻) 向电压源Vcc反向放电(即第二放电状态)，完成放电之后，检测电容对***地的电压
Figure PCTCN2019098897-appb-000002
t6时段:在完成通过第二抵消支路对检测电容的基础电容量进行抵消处理之后，开关单元K 3在其控制信号Φ5的控制下闭合，其他开关单元在各自控制信号的控制下断开，检测电容向电荷转移模块转移电荷，使得电荷转移模块生成输出电压Vout，检测电容Cx向电荷转移模块转移的电荷量为[u(t5)-Vcm]*Cx。
可选地，在本实施例中，设置所述第一抵消电阻的阻值不等于第二抵消电阻的阻值。由于电路充电和放电的速度不一样，通过设置所述第一抵消电阻的大小不等于第二抵消电阻的大小，使得在没有触摸操作时，检测电容器上的电压恰好为Vcm，从而实现完美抵消，以提高触控检测的灵敏度。
以上t1、t4是充电阶段，t2、t5是抵消阶段，t3、t6是电荷转移阶段，t1～t6是一个检测周期T。t4～t6过程实际上是t1～t3的反过程，从而削弱这两个过程电路中相关性高的噪声尤其是低频噪声。
在上述实施例中，所述电荷转移模块包括差分放大电路(比如双端差分放大器)，所述差分放大电路的反相端电连接有共模电压Vcm，所述差分放大电路的正相端在对所述检测电容进行电荷转移处理时与所述检测电容电连接，以实现检测电容的电荷转移到电荷转移模块，所述差分放大电路的正相端在对所述检测电容进行充电处理以及抵消处理时与所述检测电容断开电连接。
图1C为本申请实施例一中电容检测方法的流程示意图；针对上述图1A所示的电容检测电路，在一个检测周期内，其对应的电容检测方法包括：
本申请实施例提供一种电容检测方法，其包括：
S101、驱动模块在控制模块的控制下通过第一充电支路对检测电容进行正向充电；
结合上述图1A，开关单元K 11在所述控制模块的控制下处于闭合状态以形成所述第一充电支路。
步骤S101中通过第一充电支路对检测电容进行正向充电时，所述检测电容通过所述第一充电支路连接到正向电压源Vcc。
S102、抵消模块在所述控制模块的控制下通过第一抵消支路对所述检测电容进行基础电容量的抵消处理。
步骤S102中，所述抵消模块包括至少两个开关单元，对应地，所述控制模块控制其中一个所述开关单元K 21处于闭合时形成所述第一抵消支路。
步骤S102中，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第一抵消支路一端连接到负向电压源Vss。
S103、电荷转移模块对所述检测电容的电荷进行转移处理以生成输出电压；
如图1A所示，开关单元K 3闭合，其他开关单元处于断开状态，检测电容上的电荷转移到电荷转移模块已生成输出电压Vout。
S104、驱动模块在控制模块的控制下通过第二充电支路对所述检测电容进行反向充电；
结合上述图1A，开关单元K 12在所述控制模块的控制下处于闭合状态以形成所述第二充电支路。
结合上述图1A，通过第二充电支路对所述检测电容进行反向充电时，所述检测电容通过所述第二充电支路电连接到负向电压源Vss。
S105、抵消模块在所述控制模块的控制下通过第二抵消支路对所述检测电容进行所述基础电容量的抵消处理；
本实施例中，在步骤S105中，所述抵消模块包括至少两个开关单元，对应地，所述控制模块控制其中一个所述开关单元K 22处于闭合时形成所述第二抵消支路。
本实施例中，在步骤S105中，通过第二抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第二抵消支路一端连接到正向电压源Vcc。
S106、电荷转移模块对所述检测电容的电荷进行转移处理以生成输出电压。
如图1A所示，开关单元K 3闭合，其他开关单元处于断开状态，检测电容上的电荷转移到电荷转移模块。
当为实现检测电容的电容量变化有效检测，可以设置若干个检测周期，每个检测周期可以执行上述步骤S101-S105。
最理想的情况是，在没有触摸操作时，在t2、t5结束时，检测电容Cx上的电压恰好为Vcm，即u(t2)＝u(t5)＝Vcm时，导致转移的电荷量为0，从而实现完美抵消。那么没有触摸时，电荷转移模块的输出电压为0。当有触摸操作时，电荷转移模块的输出电压不为0。此时，放大器的输出电压完全是由触摸产生的，并且可以使用较大的放大倍数，以增加输出电压的幅度便于检测，从而提高触控灵敏度。
在完美抵消时，满足关系式：
Figure PCTCN2019098897-appb-000003
Figure PCTCN2019098897-appb-000004
可得到
Figure PCTCN2019098897-appb-000005
和
Figure PCTCN2019098897-appb-000006
可选地，在本实施例中，设置R1的大小与R2的大小不相等，由于电路充电和放电的速度不一样，通过设置R1的大小不等于R2的大小，使得在没有触摸操作时， 检测电容器上的电压恰好为Vcm，从而实现完美抵消，以提高触控检测的灵敏度。
考虑到t1～t3和t4～t6是对称的过程，t1和t4、t3和t6会设定为一样，因此期望t2与t5的值也是一样的，或接近的。根据电路的工作频率，先确定t2和t5的目标值，然后根据Vcc、Vss、Vcm的值和Cx的估计值确定电阻R1和R2的计算值。由于实际芯片的抵消电阻档位有限，R1和R2的设定值与计算值会有偏差，R1和R2的设定值只能尽可能去逼近计算值，由此在确定R1和R2的设定值后，再来微调t2和t5时间的长度，从而使得t2与t5的实际值相等或者尽可能接近，从而使正反过程都达到或接近达到完美抵消的状态。然后可以把放大电路的增益调大，以提高触控检测的灵敏度。
图2A为本申请实施例二中电容检测电路的结构示意图；图2B为本申请实施例二中电容检测电路工作时序示意图。在驱动模块的结构上，与上述实施例相同的是，其中一个开关单元K 11为单刀单掷开关单元，另外一个开关单元K 12为单刀双掷开关单元，以实现形成第一充电支路或者第二充电支路。另外，在抵消模块的结构上，在上述开关单元K 21和K 22的基础上增加了开关单元K 23，该开关单元K 23为单刀双掷开关单元，以与开关单元K 21和K 22配合实现形成第一抵消支路或者第二抵消支路。本实施例中，开关单元K 11、开关单元K 12、开关单元K 21、开关单元K 22、开关单元K 23、开关单元K 4的控制信号分别为控制信号Φ1、Φ5、Φ2、Φ3、、Φ5、Φ4。此处，需要说明的是，虽然在控制信号的附图标记上跟实施例一有相同，但并非代表其本质上与实施例一中的控制信号为相同的控制信号。
在控制的时序与实施不同的是：
在t1阶段，开关单元K 11在控制信号Φ1的控制下闭合，开关单元K 12在控制信号Φ5的控制下接触到触点1，以形成第一充电支路，开关单元K 23在控制信号Φ5下接触到触点1，但是由于开关单元K 21在控制信号Φ2的控制下断开，抵消模块不起作用。
在t2时段，开关单元K 11在控制信号Φ1的控制下断开，开关单元K 21在控制信号Φ2的控制下闭合而开关单元K 22在控制信号Φ3的控制下断开，从而形成第一抵消支路，t2时段结束后，检测电容的电压为u(t2)；
在t3时段，开关单元K 3在控制信号Φ4的控制下闭合，开关单元K 11、K 21、K 21在各自控制信号的控制下断开，检测电容上的电荷转移到电荷转移处理模块，转移的电荷量为[u(t2)-Vcm]*Cx。
在t4阶段，开关单元K 11在控制信号Φ1的控制下闭合，开关单元K 12在控制信号Φ5的控制下接触到触点2，以形成第二充电支路，开关单元K 23在控制信号Φ5下接触到触点2，但是由于开关单元K 21在控制信号Φ2的控制下断开，抵消模块不起 作用。
在t5时段，开关单元K 11在控制信号Φ1的控制下断开，开关单元K 23在控制信号Φ5的控制下接触到触点2，开关单元K 22在控制信号Φ3的控制下闭合而开关单元K 21在控制信号Φ2的控制下断开，从而形成第二抵消支路，t5时段结束后，检测电容的电压为u(t5)；
在t6时段，开关单元K 3在控制信号Φ4的控制下闭合，开关单元K 11、K 21、K 21在各自控制信号的控制下断开，检测电容上的电荷转移到电荷转移处理模块，转移的电荷量为[u(t5)-Vcm]*Cx。
可选地，在本实施例中，设置R1的大小与R2的大小不相等，由于电路充电放电的速度不一样，通过设置R1的大小不等于R2的大小，使得在没有触摸操作时，检测电容器上的电压恰好为Vcm，从而实现完美抵消，以提高触控检测的灵敏度。
参见图2A的上述过程可见，以上t1、t4是充电阶段，t2、t5是抵消阶段，t3、t6是电荷转移阶段，t1～t6是一个检测周期T。t4～t6过程实际上是t1～t3的反过程，从而削弱这两个过程电路中相关性高的噪声尤其是低频噪声。最理想的情况是，在没有触摸操作时，在t2、t5结束时，检测电容Cx上的电压恰好为Vcm，即u(t2)＝u(t5)＝Vcm时，导致转移的电荷量为0，从而实现完美抵消。那么没有触摸时，电荷转移模块的输出电压为0。当有触摸操作时，电荷转移模块的输出电压不为0。此时，放大器的输出电压完全是由触摸产生的，并且可以使用较大的放大倍数，以增加输出电压的幅度便于检测，从而提高触控灵敏度。
在完美抵消时，满足关系式：
Figure PCTCN2019098897-appb-000007
Figure PCTCN2019098897-appb-000008
可得到
Figure PCTCN2019098897-appb-000009
和
Figure PCTCN2019098897-appb-000010
考虑到t1～t3和t4～t6是对称的过程，t1和t4、t3和t6会设定为一样，因此期望t2与t5的值也是一样的，或接近的。根据电路的工作频率，先确定t2和t5的目标值，然后根据Vcc、Vss、Vcm的值和Cx的估计值确定电阻R1和R2的计算值。但是，由于实际芯片的抵消电阻档位有限，R1和R2的设定值与计算值会有偏差，实际上只能尽可能去逼近计算值。在确定R1和R2的实际值后，再来微调t2和t5时间的长度，从而使得t2与t5的实际值相等或者尽可能接近，从而使正反过程都达到或接近达到完美抵消的状态。然后可以把放大电路的增益调大，以提高触控检测的灵敏度。
图2A所示的电容检测电路实施电容检测的方法类似上述图1A所示实施例。
进一步地，在产品实现上，实际上包括若干个检测电容，则可对每个所述检测电容配置一个驱动模块、抵消模块以及电荷转移模块。与此同时，当所述电荷转移模块包括差分放大电路时，可以通过差分原理实现检测检测电容的电容变化量时相邻检测通道之间的相似特性，从而实现噪声的抑制，最终提高信噪比。以下以针对两个检测电容(分别记为Cx1、Cx2)进行处理为例进行说明。
图3A为本申请实施例三电容检测电路的结构示意图；图3B为本申请实施例三电容检测的时序示意图；如图3A所示，针对检测电容Cx1、Cx2分别设置一个驱动模块110、一个抵消模块120，与上述实施例不同的是，在电荷转移处理阶段，检测电容Cx1、Cx2分别与电荷转移处理130中的差分放大器连接，实际上同时有电荷转移到电荷转移处理模块。在图3A中，其中一个抵消模块120中的抵消电阻为R1、R2，另外一个抵消模块120中的抵消电阻为R3、R4。
因此在t1～t6各个时间段，检测电容Cx1、Cx2对应的驱动模块、抵消模块中的开关是同时导通或关断的。
在t2时刻结束时，检测电容Cx1对***地的电压
Figure PCTCN2019098897-appb-000011
在t2时刻结束时，检测电容Cx2对***地的电压
Figure PCTCN2019098897-appb-000012
在t3时刻，检测电容Cx1向电荷转移处理模块转移的电荷量为ΔQ 1＝[u 1(t 2)-V CM]C X1，检测电容Cx2向电荷转移处理模块转移的电荷量为ΔQ 2＝[u 2(t 2)-V CM]C X2，根据ΔQ1、ΔQ2的大小，存在以下几种情况：
若ΔQ1>ΔQ2，放大电路输出Vout为负向的电压；
若ΔQ1＝ΔQ2，放大电路输出Vout为0；
若ΔQ1<ΔQ2，放大电路输出Vout为正向的电压。
同理，在t5时刻，检测电容Cx1向电荷转移处理模块转移的电荷量以及检测电容Cx2向电荷转移处理模块转移的电荷量也会存在上述关系。在电路设计上，从理论角度，为实现完美抵消，要实现ΔQ1＝ΔQ2。
该实施例在相同时刻对相邻两个检测电容充电、抵消和电荷转移，并通过差分放大器将放大后的信号输出到后级电路。在触控***中，相邻的检测通道往往具有相近的基础电容量、温度变化时有相似的温度漂移量，以及相似的噪声特性。因此，该实施例能够抑制噪声，提高信噪比，以及具有抑制温漂的能力。进一步，在有触摸导致外加电场时，通过上述实施例三中Vout的方向，还可以判断出两个检测电容中那一个检测电容的电容变化量相对较大，继而根据电容量的相对大小关系，从而进一步确定触控的位置。
图4为本申请实施例四中控制电路的示例性结构图；如图4所示，其包括若 干个计数器counter(比如有五个的话，分别记为counter1、counter2、counter3、counter4、counter5)，每个计数器的输出去控制上述实施例一或者二中的开关单元，即形成上述控制信号Φ1-Φ5。这些计数器共用同一个时钟信号sys-clk，以获得相同的时钟精度。时钟频率越高，可以获得的时间控制精度也越高。因此，时钟信号一般使用触控检测***的主时钟，其主频在整个***中最高。每个计数器还有各自的数据线连接到相应的寄存器，通过修改寄存器的值来修改这些计数器的计数周期、动作时刻等，从而达到控制开关工作时序的效果。
图5为本申请实施例五中抵消电阻的示例性结构图；如图5所示，主要包括多个电阻(Res1…Resn)和多个开关(SW1…SWn)组成。每个电阻与一个开关并联形成一个组合，若干个这样的组合串接在一起。每个开关有一根控制线，所有开关的控制线并在一起连接到寄存器上。通过修改寄存器的值Code[n:0]可以使不同的开关导通和关断，从而控制抵消电阻的电阻值。
在上述实施例中，考虑到两个抵消支路放电的速率会存在差异，无法实现对检测电容的基础电容量的完美抵消(或者称之为尽量彻底抵消)，对于每一个抵消支路单独设置了一个抵消电阻，从而通过分别设计每个抵消支路中的抵消电阻大小，使得两个抵消支路的放电速率尽量相等，从而保证完美抵消的实现。为此，在抵消模块的电路设计上，参照图1，第一抵消支路中第一抵消电阻一端直接与电压源Vss连接，而另外一端与开关单元K 21连接，同样地，第二抵消支路中第二抵消电阻一端直接与电压源Vcc连接，而另外一端与开关单元K 22连接，从而使得两个抵消电路相互独立。另外，在抵消模块的电路设计上，第一抵消支路中第一抵消电阻设置在开关单元K 21和K 23之间，第一抵消电阻可通过开关单元K 21与电压源Vss连接；第二抵消支路中第二抵消电阻设置在开关单元K 22和K 23之间，第二抵消电阻可通过开关单元K 22与电压源Vcc连接；而通过开关单元K 23在触点1和触点2切换，从而分别形成第一抵消支路和第二抵消支路。
另外，在上述实施例中使用到的各个电压源可以由一电压源产生模块根据需求生成。
本申请实施例还提供一种电子设备，其包括本申请任一项实施例中所述的触控芯片。
为此，在具体应用场景中，检测电容的基础电容量越大，抵消电阻的阻值越小，反之，抵消电阻越大。另外，由于负向电压源的使用，提升了可检测到的输出电压，从而提高了信噪比。
需要说明的是，上述实施例中，虽然以一个单一的开关各个开关单元为例进行说明，但是，实际上，也可以电路组合结构的方式实现，其中组成的元件可以具有 通断功能的任意电子元器件只要可以形成充电支路、抵消支路，且可实现从充电支路到抵消支路的切换，以及使得检测电路进入电荷转移状态即可。
另外，当基于互电容检测实现触控检测时，如果互电容的基础电容量比较大以至于可影响到互电容的变化率，则也可以应用本申请下述实施例的思想。
本申请实施例的电子设备以多种形式存在，包括但不限于:
(1)移动通信设备:这类设备的特点是具备移动通信功能，并且以提供话音、数据通信为主要目标。这类终端包括:智能手机(例如iPhone)、多媒体手机、功能性手机，以及低端手机等。
(2)超移动个人计算机设备:这类设备属于个人计算机的范畴，有计算和处理功能，一般也具备移动上网特性。这类终端包括:PDA、MID和UMPC设备等，例如iPad。
(3)便携式娱乐设备:这类设备可以显示和播放多媒体内容。该类设备包括:音频、视频播放器(例如iPod)，掌上游戏机，电子书，以及智能玩具和便携式车载导航设备。
(4)服务器:提供计算服务的设备，服务器的构成包括处理器、硬盘、内存、***总线等，服务器和通用的计算机架构类似，但是由于需要提供高可靠的服务，因此在处理能力、稳定性、可靠性、安全性、可扩展性、可管理性等方面要求较高。
(5)其他具有数据交互功能的电子装置。
至此，已经对本主题的特定实施例进行了描述。其它实施例在所附权利要求书的范围内。在一些情况下，在权利要求书中记载的动作可以按照不同的顺序来执行并且仍然可以实现期望的结果。另外，在附图中描绘的过程不一定要求示出的特定顺序或者连续顺序，以实现期望的结果。在某些实施方式中，多任务处理和并行处理可以是有利的。
还需要说明的是，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、商品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、商品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括所述要素的过程、方法、商品或者设备中还存在另外的相同要素。
本说明书中的各个实施例均采用递进的方式描述，各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其他实施例的不同之处。尤其，对于***实施例而言，由于其基本相似于方法实施例，所以描述的比较简单，相关之处参见方法实施例的部分说明即可。
以上所述仅为本申请的实施例而已，并不用于限制本申请。对于本领域 技术人员来说，本申请可以有各种更改和变化。凡在本申请的精神和原理之内所作的任何修改、等同替换、改进等，均应包含在本申请的权利要求范围之内。

Claims (30)

  1. 一种电容检测电路，其特征在于，包括：控制模块、驱动模块、抵消模块以及电荷转移模块，所述驱动模块用于在所述控制模块的控制下通过第一充电支路对检测电容进行正向充电，或者，通过第二充电支路对所述检测电容进行反向充电；所述抵消模块用于在所述控制模块的控制下通过第一抵消支路对所述检测电容进行基础电容量的抵消处理，或者，在所述控制模块的控制下通过第二抵消支路对所述检测电容进行所述基础电容量的抵消处理；所述电荷转移模块用于对所述检测电容的电荷进行转移处理以生成输出电压。
  2. 根据权利要求1所述的电路，其特征在于，所述驱动模块包括至少两个开关单元，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一充电支路或者所述第二充电支路。
  3. 根据权利要求2所述的电路，其特征在于，所述开关单元为单刀单掷开关单元，所述控制模块进一步用于控制其中一个所述单刀单掷开关单元处于闭合时形成所述第一充电支路，或者，控制另外一个所述单刀单掷开关单元处于闭合时形成所述第二充电支路。
  4. 根据权利要求2所述的电路，其特征在于，所述开关单元为单刀双掷开关单元，所述控制模块进一步用于控制所述单刀双掷开关单元在不同的触点之间切换以形成述第一充电支路或者第二充电支路。
  5. 根据权利要求1-4任一项所述的电路，其特征在于，所述检测电容通过所述第一充电支路连接到正向电压源，以使第一充电支路对检测电容进行正向充电；所述检测电容通过所述第二充电支路电连接到负向电压源，以使第二充电支路对所述检测电容进行反向充电。
  6. 根据权利要求1所述的电路，其特征在于，所述抵消模块包括至少两个开关单元，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一抵消支路或者所述第二抵消支路。
  7. 根据权利要求6所述的电路，其特征在于，所述开关单元为单刀单掷开关单元，所述控制模块进一步用于控制其中一个所述单刀单掷开关单元处于闭合时形成所述第一抵消支路，或者，控制另外一个所述单刀单掷开关单元处于闭合时形成所述第二抵消支路。
  8. 根据权利要求6所述的电路，其特征在于，所述开关单元为单刀双掷开关单元，所述控制模块进一步用于控制所述单刀双掷开关单元在不同的触点之间切换以形成述第一抵消支路或者第二抵消支路。
  9. 根据权利要求1-8任一项所述的电路，其特征在于，所述抵消模块通过所述第一抵消支路一端连接到负向电压源，以使第一抵消支路对所述检测电容进行基础电容量的抵消处理；所述抵消模块通过所述第二抵消支路一端连接到正向电压源，以使第二抵消支路对所述检测电容进行基础电容量的抵消处理。
  10. 根据权利要求1-9任一项所述的电路，其特征在于，所述抵消模块包括第一抵消电阻和第二抵消电阻，所述抵消模块通过第一抵消支路对所述检测电容的基础电 容量进行抵消处理时，所述检测电容通过第一抵消电阻处于第一放电状态；所述抵消模块通过第二抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第二抵消电阻处于第二放电状态。
  11. 根据权利要求10所述的电路，其特征在于，第一抵消电阻的阻值与第二抵消电阻的阻值不相等。
  12. 根据权利要求1-11任一项所述的电路，其特征在于，通过第一充电支路对检测电容进行正向充电之后，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理；或者，通过第二充电支路对检测电容进行反向充电之后，通过第二抵消支路对所述检测电容进行基础电容量的抵消处理。
  13. 根据权利要求1-12任一项所述的电路，其特征在于，所述电荷转移模块包括差分放大电路，所述差分放大电路的反相端电连接有共模电压，所述差分放大电路的正相端与所述检测电容电连接，以使在所述检测电容进行电荷转移处理；或者所述差分放大电路的正相端与所述检测电容断开电连接，以使所述检测电容进行充电处理或者抵消处理。
  14. 根据权利要求1-13任一项所述的电路，其特征在于，若所述检测电容的数量为多个，则可对每个所述检测电容配置一个驱动模块、抵消模块以及电荷转移模块。
  15. 一种电容检测方法，其特征在于，包括：
    驱动模块在控制模块的控制下通过第一充电支路对检测电容进行正向充电，或者，通过第二充电支路对所述检测电容进行反向充电；
    抵消模块在所述控制模块的控制下通过第一抵消支路对所述检测电容进行基础电容量的抵消处理，或者，在所述控制模块的控制下通过第二抵消支路对所述检测电容进行所述基础电容量的抵消处理；
    电荷转移模块对所述检测电容的电荷进行转移处理以生成输出电压。
  16. 根据权利要求15所述的方法，其特征在于，所述驱动模块包括至少两个开关单元，对应地，还包括：所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一充电支路或者所述第二充电支路。
  17. 根据权利要求16所述的方法，其特征在于，所述开关单元为单刀单掷开关单元，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一充电支路或者所述第二充电支路，包括：所述控制模块控制其中一个所述单刀单掷开关单元处于闭合以形成所述第一充电支路，或者，所述控制模块控制另外一个所述单刀单掷开关单元处于闭合以形成所述第二充电支路。
  18. 根据权利要求16所述的方法，其特征在于，所述开关单元为单刀双掷开关单元，对应地，还包括：所述控制模块控制所述单刀双掷开关单元在不同的触点之间切换以形成述第一充电支路或者第二充电支路。
  19. 根据权利要求15-18任一项所述的方法，其特征在于，通过第一充电支路对检测电容进行正向充电时，所述检测电容通过所述第一充电支路连接到正向电压源；通过第二充电支路对所述检测电容进行反向充电时，所述检测电容通过所述第二充电支路电连接到负向电压源。
  20. 根据权利要求15所述的方法，其特征在于，所述抵消模块包括至少两个开 关单元，对应地，还包括：所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一抵消支路或者所述第二抵消支路。
  21. 根据权利要求20所述的方法，其特征在于，所述开关单元为单刀单掷开关单元，对应地，所述至少两个开关单元在所述控制模块的控制下切换开关状态以形成所述第一抵消支路或者所述第二抵消支路，包括：所述控制模块控制其中一个所述单刀单掷开关单元处于闭合时形成所述第一抵消支路，或者，控制另外一个所述单刀单掷开关单元处于闭合时形成所述第二抵消支路。
  22. 根据权利要求20所述的方法，其特征在于，所述开关单元为单刀双掷开关单元，对应地，还包括：所述控制模块控制所述单刀双掷开关单元在不同的触点之间切换以形成述第一抵消支路或者第二抵消支路。
  23. 根据权利要求15-22任一项所述的方法，其特征在于，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第一抵消支路一端连接到负向电压源；通过第二抵消支路对所述检测电容进行基础电容量的抵消处理时，所述抵消模块通过所述第二抵消支路一端连接到正向电压源。
  24. 根据权利要求15-23任一项所述的方法，其特征在于，所述抵消模块包括第一抵消电阻和第二抵消电阻，所述抵消模块通过第一抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第一抵消电阻处于第一放电状态；所述抵消模块通过第二抵消支路对所述检测电容的基础电容量进行抵消处理时，所述检测电容通过第二抵消电阻处于第二放电状态。
  25. 根据权利要求15-24任一项所述的方法，其特征在于，通过第一充电支路对检测电容进行正向充电之后，通过第一抵消支路对所述检测电容进行基础电容量的抵消处理；或者，通过第二充电支路对检测电容进行反向充电之后，通过二抵消支路对所述检测电容进行基础电容量的抵消处理。
  26. 根据权利要求25所述的方法，其特征在于，第一抵消电阻的阻值与第二抵消电阻的阻值不相等。
  27. 根据权利要求15-26任一项所述的方法，其特征在于，所述电荷转移模块包括差分放大电路，所述差分放大电路的反相端电连接有共模电压，所述差分放大电路的正相端在对所述检测电容进行电荷转移处理时与所述检测电容电连接，所述差分放大电路的正相端在对所述检测电容进行充电处理以及抵消处理时与所述检测电容断开电连接。
  28. 根据权利要求15-27任一项所述的方法，其特征在于，若所述检测电容的数量为多个，则可对每个所述检测电容配置一个驱动模块、抵消模块以及电荷转移模块。
  29. 一种触控芯片，包括：权利要求1-15任一项所述的电路。
  30. 一种电子设备，其特征在于，包括权利要求29所述的触控芯片。
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