WO2022141248A1 - 接近检测电路、可穿戴设备和接近检测方法 - Google Patents

接近检测电路、可穿戴设备和接近检测方法 Download PDF

Info

Publication number
WO2022141248A1
WO2022141248A1 PCT/CN2020/141618 CN2020141618W WO2022141248A1 WO 2022141248 A1 WO2022141248 A1 WO 2022141248A1 CN 2020141618 W CN2020141618 W CN 2020141618W WO 2022141248 A1 WO2022141248 A1 WO 2022141248A1
Authority
WO
WIPO (PCT)
Prior art keywords
detection
capacitance
self
channel
signal
Prior art date
Application number
PCT/CN2020/141618
Other languages
English (en)
French (fr)
Inventor
唐玲裕
Original Assignee
深圳市汇顶科技股份有限公司
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 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/CN2020/141618 priority Critical patent/WO2022141248A1/zh
Publication of WO2022141248A1 publication Critical patent/WO2022141248A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation

Definitions

  • the embodiments of the present application relate to the field of capacitance detection, and more particularly, to a proximity detection circuit, a wearable device, and a proximity detection method.
  • a proximity detection circuit is usually used to detect the user's touch or approach to the earphones.
  • the proximity detection circuit can obtain the information of the user's proximity to the earphone by detecting the change of the self-capacitance of the detection electrode in the earphone to the ground, so as to determine the wearing condition of the earphone and make the earphone perform the corresponding operation.
  • the playback operation is performed, and the playback pause operation is performed when the earphone is detected to be removed from the user's ear.
  • the detection electrodes are usually connected to an electrostatic discharge (Electrostatic Discharge, ESD) protection circuit, and the ESD protection circuit includes protection devices such as transient voltage suppression (Transient Voltage Suppression, TVS) diodes.
  • ESD Electrostatic Discharge
  • TVS Transient Voltage Suppression
  • Embodiments of the present application provide a proximity detection circuit, a wearable device, and a proximity detection method, which can improve the detection performance of the proximity detection circuit in the wearable device.
  • a proximity detection circuit provided in a wearable device, the proximity detection circuit is connected to a plurality of detection channels in the wearable device, and at least part of the detection channels in the plurality of detection channels are An ESD protection circuit is connected thereon, and the proximity detection circuit includes: a self-capacitance drive circuit for inputting a self-capacitance drive signal to a first detection channel to be detected among the plurality of detection channels, and the first detection channel is connected to With the ESD protection circuit, the self-capacitance detection signal output by the first detection channel under the action of the self-capacitance driving signal, the self-capacitance of the detection electrode associated with the first detection channel is relative to the self-capacitance basic capacitance
  • the self-capacitance change of the ESD protection circuit and the capacitance change caused by the ESD protection circuit being exposed to light, the self-capacitance basic capacitance includes: when no user approaches the detection electrode of the first detection channel and the ESD protection circuit is not exposed
  • the mutual capacitance variation of the mutual capacitance between the detection electrode of a detection channel and the detection electrode of the second detection channel relative to the mutual capacitance basic capacitance where the mutual capacitance basic capacitance includes: no user approaches the first detection channel When the detection electrode of the first detection channel and the detection electrode of the second detection channel are detected, the mutual capacitance between the detection electrode of the first detection channel and the detection electrode of the second detection channel; and a signal processing circuit for according to the The self-capacitance detection signal and the mutual capacitance detection signal determine the detection result of whether the user is approaching the wearable device.
  • the proximity detection circuit performs both self-capacitance detection on the detection electrodes and mutual capacitance detection on the detection electrodes. Since the mutual capacitance detection is basically not affected by the capacitance change of the ESD protection device, the mutual capacitance detection is based on mutual capacitance detection.
  • the detection signals of the capacitance detection and the self-capacitance detection jointly determine the final detection result, which can effectively improve the accuracy of the detection result and improve the detection performance of the proximity detection circuit.
  • the mutual capacitance detection signal is used to determine whether the self-capacitance detection signal is valid.
  • the mutual capacitance detection signal output during mutual capacitance detection can be used to determine whether the self-capacitance detection signal output during self-capacitance detection is valid, that is, the mutual capacitance detection signal is used as an auxiliary to determine the validity of the self-capacitance detection signal. Since the mutual capacitance detection is basically not affected by the capacitance change of the ESD protection device, judging the validity of the self-capacitance detection signal output during self-capacitance detection based on the mutual capacitance detection signal can ensure that the self-capacitance detection signal is generated by the user close to the wearable equipment, thereby improving the accuracy of the detection results.
  • the self-capacitance detection signal when the mutual capacitance detection signal is greater than a preset first threshold, the self-capacitance detection signal is determined to be valid; and/or, when the mutual capacitance detection signal is smaller than the When the first threshold value is reached, the self-capacitance detection signal is judged to be invalid.
  • the first threshold is used to indicate the threshold of the mutual capacitance detection signal when the user approaches the wearable device.
  • the threshold can be determined according to the value of the mutual capacitance detection signal when the user approaches the detection electrode. For example, it may be 0.2-0.8 times the value of the mutual capacitance detection signal when the user approaches the detection electrode.
  • the mutual capacitance detection signal is less than the threshold, there may be no user approach at this time, then the self-capacitance detection signal can be considered invalid, because the magnitude of the self-capacitance detection signal is likely to reflect the TVS in the ESD protection circuit
  • the capacitance change of the diode affected by the light when the mutual capacitance detection signal is greater than the threshold, it can be considered that the user is close to the detection electrode at this time, and the self-capacitance detection signal can be considered effective.
  • the self-capacitance detection signal when the self-capacitance detection signal is determined to be valid, the self-capacitance detection signal is used to determine the detection result; and/or, when the self-capacitance detection signal is determined to be invalid , the proximity detection circuit acquires the self-capacitance detection signal again.
  • the self-capacitance detection signal is considered valid, and the detection result can be determined based on the self-capacitance detection signal; if the self-capacitance detection signal is considered invalid, the self-capacitance detection signal can be re-acquired, or the self-capacitance detection signal can be re-acquired based on the mutual The detection signal determines the detection result. In this way, the self-capacitance detection signal caused by the capacitance change of the ESD protection device can be excluded, thereby improving the accuracy of the detection result.
  • the signal processing circuit is configured to: when the self-capacitance detection signal is determined to be valid, if the self-capacitance detection signal is greater than a preset second threshold, determine that the user is approaching the possible A wearable device; wherein the second threshold is used to indicate a threshold of a self-capacitance detection signal when a user approaches the wearable device.
  • the self-capacitance detection signal is judged to be valid, indicating that the self-capacitance detection signal is not caused by the capacitance change of the ESD protection device.
  • the self-capacitance detection signal is greater than the preset second threshold, it indicates that a user is approaching the wearable device. Accordingly, the detection result obtained at this time is accurate. Therefore, in the above manner, the accuracy of the detection result can be ensured.
  • a detection period of the proximity detection circuit includes a first period, a second period, and a third period, wherein the first period is used to obtain all the corresponding values of the first detection channel.
  • the self-capacitance change amount, the second period is used to obtain the self-capacitance change amount corresponding to the second detection channel, and the third period is used to obtain the detection electrode of the first detection channel and the first detection channel.
  • a detection cycle of the proximity detection circuit includes a period of self-capacitance detection, and also includes a period of mutual capacitance detection.
  • the proximity detection circuit performs capacitance detection according to the timing sequence, which can effectively obtain the self-capacitance detection signal and the mutual capacitance detection. Signal.
  • the ESD protection circuit is connected to the second detection channel, or the ESD protection circuit is not connected to the second detection channel.
  • the ESD protection circuit includes a transient voltage suppression TVS diode.
  • the proximity detection circuit further includes: a multiplexer, which is respectively connected to the plurality of detection channels, the self-capacitance driving circuit and the mutual-capacity driving circuit, and is used to connect all the The detection channel to be detected among the plurality of detection channels is electrically connected to the self-capacitance driving circuit or the mutual capacitance driving circuit.
  • the signal processing circuit includes: an analog front-end AFE circuit, connected to the multiplexer, for receiving the self-capacitance detection signal and the mutual-capacitance detection signal, and for all The self-capacitance detection signal and the mutual capacitance detection signal are subjected to signal processing to improve the signal quality of the self-capacitance detection signal and the mutual capacitance detection signal.
  • the signal processing circuit includes: a DAQ, for collecting the self-capacitance detection signal and the mutual capacitance detection signal; and a DSP circuit, connected to the DAQ circuit, for collecting the The self-capacitance detection signal and the mutual capacitance detection signal determine the detection result.
  • a wearable device including the proximity detection circuit in the first aspect or any possible implementation manner of the first aspect.
  • a proximity detection method comprising: inputting a self-capacitance driving signal to a first detection channel to be detected in a wearable device, wherein an electrostatic discharge ESD protection circuit is connected to the first detection channel; Obtain a self-capacitance detection signal output by the first detection channel under the action of the self-capacitance drive signal, where the self-capacitance detection signal is related to the self-capacitance of the detection electrode of the first detection channel relative to the self-capacitance base capacitance
  • the self-capacitance change of the ESD protection circuit and the capacitance change caused by the ESD protection circuit being exposed to light, the self-capacitance basic capacitance includes: when no user approaches the detection electrode of the first detection channel and the ESD protection circuit is not exposed to light , the self-capacitance of the detection electrode of the first detection channel; output a mutual capacitance drive signal to one of the first detection channel and the second detection channel; obtain under the action of the mutual capacitance
  • the determining the detection result of whether the user is approaching the wearable device according to the self-capacitance detection signal and the mutual capacitance detection signal includes: judging the wearable device according to the mutual capacitance detection signal. Whether the self-capacitance detection signal is valid; when the self-capacitance detection signal is determined to be valid, the detection result is determined according to the self-capacitance detection signal.
  • the determining whether the self-capacitance detection signal is valid according to the mutual capacitance detection signal includes: when the mutual capacitance detection signal is greater than a preset first threshold, determining whether the self-capacitance detection signal is valid. and/or, when the mutual capacitance detection signal is smaller than the first threshold, determine that the self-capacitance detection signal is invalid; wherein the first threshold is used to indicate that the user is approaching the acceptable Threshold of mutual capacitance detection signal when wearing the device.
  • the method further includes: reacquiring the self-capacitance detection signal when the self-capacitance detection signal is determined to be invalid.
  • determining the detection result according to the self-capacitance detection signal includes: when the self-capacitance detection signal is determined to be valid, if the When the self-capacitance detection signal is greater than a preset second threshold, it is determined that the user is approaching the wearable device; wherein the second threshold is used to indicate the threshold of the self-capacitance detection signal when the user approaches the wearable device.
  • the self-capacitance variation corresponding to the first detection channel is acquired in a first period of a detection period, and the corresponding amount of the second detection channel is acquired in a second period of the detection period
  • the self-capacitance change amount corresponding to the mutual capacitance change amount between the detection electrodes of the first detection channel and the detection electrodes of the second detection channel is acquired in the third period of the detection period.
  • FIG. 1 is a schematic block diagram of a proximity detection circuit according to an embodiment of the present application.
  • FIG. 2 is a schematic diagram of a possible implementation based on the proximity detection circuit shown in FIG. 1 .
  • FIG. 3 is a schematic flowchart of a proximity detection method according to an embodiment of the present application.
  • proximity detection circuits are usually used to detect the user's touch or approach to the wearable device.
  • the proximity detection circuit can determine whether the user is currently wearing the earphone by detecting the change of the self-capacitance of the detecting electrode in the earphone.
  • the detection electrodes are usually connected to an external ESD protection circuit.
  • This application does not make any limitation on the ESD protection circuit, which can be a protection circuit formed by any ESD protection device.
  • the ESD protection circuit includes a TVS diode as an example for description.
  • Wearable devices generally include several detection channels, such as two or more than a dozen detection channels.
  • the proximity detection circuit determines whether the user is approaching the The detection result of the wearable device, so that the wearable device performs a matching operation according to the detection result.
  • the above-mentioned “proximity” may include contacting or approaching. For example, a playback operation is performed when it is detected that the earphone is close to the user's ear, and an operation of pause playback is performed when it is detected that the earphone is away from the user's ear.
  • the threshold may be a threshold for indicating the amount of capacitance change when the user approaches the wearable device.
  • the TVS diode connected to the detection channel and the ground, which is also called the junction capacitance of the TVS diode.
  • the TVS diode is easily affected by external light, and its capacitance to ground changes with the light. This capacitance change will affect the detection result of the self-capacitance of the detection electrode, thereby affecting the detection result.
  • FIG. 1 is a schematic block diagram of a proximity detection circuit according to an embodiment of the present application.
  • FIG. 2 is a schematic diagram of a possible implementation based on the proximity detection circuit shown in FIG. 1 .
  • the proximity detection circuit 200 is connected to the detection channel C 0 to the detection channel CN .
  • the following description takes the detection channel C 0 and the detection channel C 1 as an example. In FIG. 2 , only the detection channel C 0 and the detection channel C 1 are shown. Circuit structure on the two branches of channel C1 . As shown in FIG.
  • the detection channel C 0 and the detection channel C 1 are respectively connected to the TVS diode D 0 and the TVS diode D 1 .
  • the self-capacitance of the detection electrode S 0 on the detection channel C 0 to the ground is C S0
  • the self-capacitance of the detection electrode S 1 on the detection channel C 1 to the ground is C S1 .
  • the size of the self-capacitance C S0 of the detection electrode S 0 will change, and the capacitance change of the self-capacitance C S0 is ⁇ C S0 body .
  • the self-capacitance change amount ⁇ C S0body is valid data expected to be detected by the proximity detection circuit 200 .
  • the capacitance C j0 of the TVS diode D 0 connected to the detection channel C 0 to the ground also changes, and the capacitance change is ⁇ C j0 .
  • the capacitance change reflected by the detection signal output on the detection channel C 0 includes ⁇ C S0body and ⁇ C j0 .
  • the proximity detection circuit 200 will mistakenly think that the capacitance changes of the two parts ⁇ C S0body and ⁇ C j0 are valid data, so as to determine the detection result of the detection channel C 0 according to the ⁇ C S0 body and ⁇ C j0 , that is, whether the user is approaching the detection electrode S 0 detection result.
  • the capacitance change of the self-capacitance C S1 is ⁇ C S1body .
  • the self-capacitance change amount ⁇ C S1body is valid data expected to be detected by the proximity detection circuit 200 .
  • the capacitance C j1 of the TVS diode D 1 connected to the detection channel C 1 to the ground also changes, and the capacitance change is ⁇ C j1 .
  • the capacitance variation reflected by the detection signal output from the detection channel C1 includes ⁇ C S1body and ⁇ C j1 .
  • the proximity detection circuit 200 will mistakenly think that the capacitance changes of ⁇ C S1body and ⁇ C j1 are valid data, so as to determine the detection result of the detection channel C 1 according to the ⁇ C S1 body and ⁇ C j1 , that is, whether the user is approaching the detection electrode S 1 test results.
  • the wearable device may detect that the capacitance change of the above-mentioned self-capacitance reaches the threshold. It will think that the wearable device is worn on the user, and then start to play music and other response events; on the other hand, after the wearable device normally responds to the event that the user approaches the wearable device, due to the influence of light, when the wearable device The wearable device may also be mistakenly identified as still being worn by the user, and the wearable device cannot exit the above-mentioned response event normally.
  • the earphone As an example, it is assumed that when the self-capacitance change ⁇ C S0body of the detection electrode S 0 on the detection channel C 0 in FIG. 2 is greater than the threshold A, it is considered that the user is wearing the earphone, so that the earphone performs the playback operation; and ⁇ C When the S0body is smaller than the threshold value A, it is considered that the user takes off the earphone, so that the earphone performs the operation of pausing playback.
  • the headset When there is light, if the user does not wear the headset, but the capacitance change ⁇ C j0 of the TVS diode D 0 is greater than the threshold A due to the light, the headset will also perform a playback operation, resulting in a false response.
  • the earphone does not think that the user has taken off the earphone, but continues to play, unable to Exit normally.
  • an embodiment of the present application provides a proximity detection circuit, by adding mutual capacitance detection as an auxiliary on the basis of self-capacitance detection, so as to reduce the influence of the ESD protection circuit on the self-capacitance detection due to illumination, and improve the proximity detection circuit.
  • the accuracy of the capacitance detection results is improved, thereby reducing the misjudgment of the event that the human body approaches the wearable device.
  • FIG. 1 is a schematic block diagram of a proximity detection circuit 200 according to an embodiment of the present application.
  • the proximity detection circuit 200 can be applied to wearable devices, including but not limited to TWS earphones (including in-ear, semi-in-ear and head-mounted, etc.), smart watches, smart glasses and other smart wearable devices.
  • TWS earphones including in-ear, semi-in-ear and head-mounted, etc.
  • smart watches smart glasses and other smart wearable devices.
  • the proximity detection circuit 200 is connected to several detection channels in the wearable device, and at least part of the several detection channels is connected with an ESD protection circuit, and the ESD protection circuit includes a TVS diode. As shown in FIG. 2 , the proximity detection circuit 200 includes a self-capacitance driving circuit 210 , a mutual capacitance driving circuit 220 and a signal processing circuit 215 .
  • the self-capacitance driving circuit 210 is used for inputting a self-capacitance driving signal to a first detection channel to be detected among the plurality of detection channels, and an ESD protection circuit is connected to the first detection channel.
  • the self-capacitance detection signal output by the first detection channel under the action of the self-capacitance driving signal, the self-capacitance change of the detection electrode of the first detection channel relative to the self-capacitance basic capacitance, and the ESD protection circuit The amount of capacitance change caused by light exposure.
  • the mutual capacitance driving circuit 220 is configured to output a mutual capacitance driving signal to one of the first detection channel and the second detection channel.
  • the second detection channel may be any detection channel that forms mutual capacitance detection with the first detection channel.
  • the mutual capacitance detection signal output by the first detection channel and the other detection channel of the second detection channel is associated with the detection electrode of the first detection channel and the second detection channel
  • the mutual capacitance variation of the mutual capacitance between the detection electrodes relative to the mutual capacitance base capacitance is associated with the detection electrode of the first detection channel and the second detection channel.
  • the signal processing circuit 215 is configured to determine the detection result of whether the user is approaching the wearable device according to the self-capacitance detection signal and the mutual capacitance detection signal.
  • the proximity detection circuit 200 not only performs self-capacitance detection on the detection electrodes, but also performs mutual capacitance detection on the detection electrodes. Since the mutual capacitance detection is basically not affected by the capacitance change of the ESD protection device, based on the The detection signals of mutual capacitance detection and self-capacitance detection jointly determine the final detection result, which can effectively improve the accuracy of the detection result and improve the detection performance of the proximity detection circuit. Moreover, the detection circuit provided by the present application can use common ESD protection devices, which can still ensure ESD protection, improve the accuracy of proximity detection, reduce the requirements for ESD device selection, and reduce the use of specific ESD devices. cost impact.
  • self-capacitance detection of proximity detection circuits in wearable devices can accommodate longer detection distances than mutual-capacitance detection.
  • the position of the detection electrode of the earphone and the fit degree of the ear are different, which may be completely fitted or there may be a certain distance (such as rotating the earphone or Headphones come loose due to human movement).
  • self-capacitance detection it can adapt to a larger detection distance, while mutual capacitance detection can adapt to a smaller detection distance. Therefore, for wearable devices such as earphones, the approach of a user is mainly detected by means of self-capacitance detection.
  • the proximity detection circuit uses the mutual capacitance detection result to assist in judging the self-capacitance detection result, thereby improving the accuracy of the detection result and reducing misjudgment of the user approaching event.
  • the embodiment of the present application does not limit the ESD protection circuit.
  • a TVS diode can be used as the ESD protection device in the ESD protection circuit.
  • the description will be given by taking the TVS diode as an ESD protection device as an example.
  • the aforementioned self-capacitance detection signal is not only related to the self-capacitance change of the detection electrode of the first detection channel, but also to the capacitance change of the TVS diode caused by illumination.
  • ESD protection circuits can only be connected to some detection channels. For example, in the first detection channel and the second detection channel, only one of the detection channels can be detected.
  • the ESD protection circuit is connected to the channel, and the ESD protection circuit can also be connected to both detection channels.
  • each detection channel can be tested for static electricity to find the detection channels that are easily affected by static electricity, and connect ESD protection circuits to these detection channels, while the detection channels that are not easily affected by static electricity may not be connected to ESD protection. circuit.
  • the embodiments of the present application do not limit the shape and size of the detection electrodes on the detection channels.
  • the proximity detection circuit 200 When the proximity detection circuit 200 performs self-capacitance detection on the first detection channel, it detects the variation of the self-capacitance between the detection electrode of the first detection channel and the ground relative to the self-capacitance basic capacitance; and when performing mutual capacitance detection, What is detected is the variation of the mutual capacitance between the detection electrodes of the first detection channel and the detection electrodes of the second detection channel relative to the mutual capacitance base capacitance. It should be understood that, regarding the detection of the capacitance change, the change may be directly measured, or the change may be obtained indirectly, that is, the detection value is measured first, and then the change is obtained according to the detection value and the basic value.
  • the TVS diode is grounded to transfer the electrostatic charge generated when static electricity occurs to the ground.
  • the capacitance change generated when the TVS diode is illuminated will affect the self-capacitance detection result.
  • the loop during mutual capacitance detection passes between the two detection electrodes. Therefore, the capacitance change generated when the TVS diode is illuminated will basically not affect the results of mutual capacitance detection.
  • the above-mentioned self-capacitance basic capacitance includes: when no user approaches the first detection channel and the TVS diode connected to the first detection channel is not illuminated, the self-capacitance of the detection electrode of the first detection channel.
  • the self-capacitance corresponding to the first detection channel will change. According to the magnitude of the self-capacitance change, it can be determined Whether the user is close to the position corresponding to the first detection channel.
  • the above-mentioned mutual capacitance basic capacitance includes: when no user approaches the first detection channel and the second detection channel, and the TVS diode is not illuminated, the detection electrodes of the first detection channel and the second detection channel detect mutual capacitance between electrodes.
  • the mutual capacitance corresponding to the first detection channel will change on the basis of the mutual capacitance basic capacitance. size, it can be determined whether the user is close to the position corresponding to the first detection channel or the second detection channel.
  • the self-capacitance detection signal obtained by the proximity detection circuit 200 when performing self-capacitance detection and the mutual-capacitance detection signal obtained when performing mutual-capacitance detection are jointly used to determine the detection result.
  • the mutual capacitance detection signal can be used to determine whether the self capacitance detection signal is valid.
  • the mutual capacitance detection signal is greater than a preset first threshold, the self-capacitance detection signal is determined to be valid; and/or, when the mutual capacitance detection signal is less than the first threshold, the self-capacitance detection signal is The detection signal is judged to be invalid.
  • the first threshold is used to indicate the threshold of the mutual capacitance detection signal when the user approaches the wearable device.
  • the first threshold may be set according to the specific product form.
  • the first threshold may be, for example, several tens of fF to several hundreds of fF.
  • the mutual capacitance detection is basically not affected by the capacitance change of the ESD protection device, judging the validity of the self-capacitance detection signal output during self-capacitance detection based on the mutual capacitance detection signal can ensure that the self-capacitance detection signal is generated by the user close to the wearable equipment, thereby improving the accuracy of the detection results.
  • the self-capacitance detection signal when the self-capacitance detection signal is determined to be valid, the self-capacitance detection signal is used to determine the detection result; and/or, when the self-capacitance detection signal is determined to be invalid, the proximity detection circuit re-acquires the self-capacitance detection signal. capacity detection signal.
  • the detection result can be determined based on the self-capacitance detection signal; if the self-capacitance detection signal is considered to be invalid, the self-capacitance detection signal can be re-acquired, or can also be based on The mutual capacitance detection signal determines the detection result. In this way, the self-capacitance detection signal caused by the capacitance change of the ESD protection device can be excluded, thereby improving the accuracy of the detection result.
  • the self-capacitance detection signal when the self-capacitance detection signal is determined to be valid, if the self-capacitance detection signal is greater than a preset second threshold, it is determined that the user is approaching the wearable device; wherein the second threshold is used to indicate The threshold of the self-capacitance detection signal when the user approaches the wearable device.
  • the self-capacitance detection signal is judged to be valid, indicating that the self-capacitance detection signal is not caused by the capacitance change of the ESD protection device.
  • the self-capacitance detection signal is greater than the preset second threshold, it indicates that a user is approaching the wearable device. Accordingly, the detection result obtained at this time is accurate. Therefore, in the above manner, the accuracy of the detection result can be ensured.
  • FIG. 2 is a schematic diagram based on a possible implementation of the proximity detection circuit 200 shown in FIG. 1 .
  • the proximity detection circuit 200 is connected to the detection channel C 0 to the detection channel CN .
  • the following description takes the detection channel C 0 and the detection channel C 1 as an example. In FIG. 2 , only the detection channel C 0 and the detection channel C 1 are shown. Circuit structure on the two branches of channel C1 .
  • the detection channel C 0 and the detection channel C 1 are respectively connected to the TVS diode D 0 and the TVS diode D 1 .
  • the self-capacitance of the detection electrode S 0 on the detection channel C 0 to the ground is C S0
  • the self-capacitance of the detection electrode S 1 on the detection channel C 1 to the ground is C S1
  • the detection electrode on the detection channel C 0 is C S1
  • the mutual capacitance between S 0 and the detection electrode S 1 on the detection channel C 1 is C m
  • the capacitance of the TVS diode D 0 to ground and the capacitance of the TVS diode D 1 to the ground are C j0 and C j1 , respectively.
  • the self-capacitance driving circuit 210 can input a self-capacitance driving signal to the detection channel C 0 and receive the self-capacitance detection signal output by the detection channel C 0 , and the self-capacitance detection signal reflects the is the self-capacitance change ⁇ C S0 body of the detection electrode C S0 and the capacitance change ⁇ C j0 of the TVS diode; the mutual capacitance drive circuit 220 can input the mutual capacitance to one of the detection channel C 0 and the detection channel C 1 The driving signal is received, and the mutual capacitance detection signal output by the other detection channel is received.
  • the self-capacitance detection signal reflects the mutual capacitance variation ⁇ C mbody between the detection electrode C S0 and the detection electrode C S1 .
  • the threshold B is set, if the mutual capacitance detection signal is greater than the threshold B, the self-capacitance detection signal is considered to be valid, and the proximity detection circuit 200 can determine whether the user is approaching the corresponding position of the first detection channel according to the self-capacitance detection signal; If the signal is smaller than the threshold value B, it is considered that the self-capacitance detection signal is invalid, and at this time, the proximity detection circuit 200 can obtain the self-capacitance detection signal again.
  • the earphone As an example, it is assumed that when the self-capacitance change ⁇ C S0body of the detection electrode S 0 on the detection channel C 0 in FIG. 2 is greater than the threshold A, it is considered that the user is wearing the earphone, so that the earphone performs the playback operation; and ⁇ C When the S0body is smaller than the threshold value A, it is considered that the user takes off the earphone, so that the earphone performs the operation of pausing playback.
  • the earphone When there is light, if the user does not wear the earphone, but the amount of capacitance change ⁇ C j0 of the TVS diode D 0 is greater than the threshold A due to the light, the earphone will also perform a playback operation, resulting in a false response. At this time, if the mutual capacitance detection signal used to represent the mutual capacitance change ⁇ C mbody is less than the threshold B, the above detection result will be judged to be invalid, so that the headphones will not be misplayed; if the mutual capacitance detection signal is greater than the threshold B, then The above detection result will be judged to be valid, and the playback will be executed.
  • a detection period of the proximity detection circuit 200 includes a first period, a second period and a third period.
  • the three time periods are respectively used for self-capacitance detection of the first detection channel, self-capacitance detection of the second detection channel, and mutual capacitance detection between the first detection channel and the second detection channel.
  • the time sequence of the first time period, the second time period and the third time period is not limited here.
  • the detection cycle includes a first period of time, a second period of time, and a third period of time according to time sequence.
  • the first time period is used to obtain the self-capacitance change corresponding to the first detection channel
  • the second time period is used to obtain the self-capacitance change corresponding to the second detection channel
  • the third time period is used to obtain the detection electrode and the first detection channel.
  • the detection results of the first detection channel and the second detection channel can be comprehensively determined according to the data of the self-capacitance detection and the mutual capacitance detection. In this way, an accurate detection result of the corresponding detection channel can be obtained within one detection period.
  • serial detection is usually adopted. As shown in Fig. 2, in one detection cycle, the self-capacitance change of the detection electrode on the detection channel C 0 and the self-capacitance change of the detection electrode on the detection channel C 1 are detected, and the difference between the two is detected.
  • the mutual capacitance change is detected; then, in the next detection cycle, the self-capacitance change of the detection electrode on the detection channel C2 and the self - capacitance change of the detection electrode on the detection channel C3 are detected, and the two The change in mutual capacitance between them is detected; in turn, similarly, the remaining detection channels are detected in sequence in the subsequent detection cycle, until finally the change in self-capacitance of the detection electrode on the detection channel CN-1 and The self-capacitance variation of the detection electrodes on the detection channel CN is detected, and the mutual capacitance variation between the two is detected.
  • the proximity detection circuit 200 may further include a multiplexer 230 .
  • the multiplexer 230 is connected to several detection channels, the self-capacitance driving circuit 210 and the mutual capacitance driving circuit 220 in the wearable device, and is used to electrically connect the detection channel to be detected among the several detection channels to the self-capacitance driving circuit circuit 210 or the mutual capacitance driving circuit 220 .
  • the signal processing circuit 215 may include an analog front end (Analog Front End, AFE) circuit 240 .
  • the AFE circuit 240 is connected to the multiplexer 230 for receiving the self-capacitance detection signal and the mutual-capacitance detection signal, and performing signal conditioning on the self-capacitance detection signal and the mutual-capacitance detection signal to improve the difference between the self-capacitance detection signal and the mutual-capacitance detection signal. Signal quality.
  • the signal processing circuit 215 may include a data acquisition circuit (Data Acquisition Circuit, DAQ) 250 and a digital signal processing circuit (Digital Signal Processor, DSP) 260.
  • DAQ Data Acquisition Circuit
  • DSP Digital Signal Processor
  • the DAQ 250 is used to acquire self-capacitance detection signals and mutual capacitance detection signals.
  • the DAQ 250 can be connected to the AFE circuit 240 for collecting the self-capacitance detection signal and the mutual capacitance detection signal processed by the AFE circuit 240.
  • the DSP circuit 260 is connected to the DAQ circuit 250 for determining the detection result according to the self-capacitance detection signal and the mutual capacitance detection signal.
  • the multiplexer (Multiplexer) 230 may also be referred to as a multiplexer, a data selector, etc., and is a device that can select one signal from a plurality of signals for input or output. For its specific description, reference may be made to the description of the multiplexer in the related art, which will not be repeated here. Any detection channel can be switched and connected to the self-capacitance driving circuit 210 , the mutual capacitance driving circuit 220 and the AFE circuit 240 through the multiplexer 230 .
  • the current detection is the self-capacitance of the detection electrode of the first detection channel to the ground
  • the multiplexer 230 can select the first detection channel in several detection channels, so that the driving signal of the self-capacitance driving circuit 210 It can be input to the first detection channel, and the self-capacitance detection signal output by the first detection channel can be output to the AFE circuit 240 through the multiplexer 230 .
  • the current detection is the self-capacitance of the detection electrode of the second detection channel to the ground
  • the multiplexer 230 can select the second detection channel in several detection channels, so that the self-capacitance driving circuit 210 can drive the self-capacitance driving circuit 210.
  • the signal may be input to the second detection channel, and the self-capacitance detection signal output by the second detection channel may be output to the AFE circuit 240 through the multiplexer 230 .
  • the current detection is the mutual capacitance between the detection electrodes of the first detection channel and the detection electrodes of the second detection channel
  • the multiplexer 230 may select the first detection channel and the second detection channel in several detection channels. Two detection channels, so that the driving signal of the self-capacitance driving circuit 210 is input to the first detection channel, and the mutual capacitance detection signal output by the second detection channel is output to the AFE circuit 240 through the multiplexer 230; The driving signal of the capacitance driving circuit 210 is input to the second detection channel, and the mutual capacitance detection signal output by the first detection channel is output to the AFE circuit 240 through the multiplexer 230 .
  • the AFE circuit 240 is an integrated component including an amplifier circuit, a filter circuit, an analog-to-digital conversion circuit, etc., and can be used to amplify, filter, and convert the self-capacitance detection signal and the mutual capacitance detection signal.
  • This embodiment of the present application does not limit the specific structure of the AFE circuit 240 .
  • the proximity detection circuit 200 may also include other circuit components, such as auxiliary circuits, power supply circuits, etc., which are not illustrated here.
  • the proximity detection circuit 200 may be an integrated circuit, that is, the above circuit modules 210 to 260 may be integrated on a chip; or, the above circuit modules 210 to 260 may also be discrete circuit modules. This embodiment of the present application does not limit this.
  • Embodiments of the present application further provide a wearable device, including the proximity detection circuit 200 in the above-mentioned various embodiments of the present application.
  • the embodiment of the present application also provides a proximity detection method 300 .
  • This method can be applied to the proximity detection circuit 200 and the wearable device in the various embodiments of the present application described above. As shown in FIG. 3, the method 300 may include:
  • Input a self-capacitance drive signal to a first detection channel to be detected in the wearable device, where an electrostatic discharge ESD protection circuit is connected to the first detection channel;
  • the self-capacitance basic capacitance includes: no user approaches the detection electrode of the first detection channel and the ESD protection circuit is not affected When illuminated, the self-capacitance of the detection electrode of the first detection channel;
  • the mutual capacitance variation is the mutual capacitance variation of the mutual capacitance between the detection electrodes of the first detection channel and the detection electrodes of the second detection channel relative to the mutual capacitance basic capacitance
  • the mutual capacitance The basic capacitance includes: when no user approaches the detection electrode of the first detection channel and the detection electrode of the second detection channel, the capacitance between the detection electrode of the first detection channel and the detection electrode of the second detection channel is mutual capacitance;
  • the mutual capacitance detection signal when the mutual capacitance detection signal is greater than a preset first threshold, it is determined that the self-capacitance detection signal is valid; and/or, when the mutual capacitance detection signal is smaller than the When the first threshold is used, it is determined that the self-capacitance detection signal is invalid; wherein, the first threshold is used to indicate the threshold of the mutual-capacity detection signal when the user approaches the wearable device.
  • the self-capacitance detection signal when the self-capacitance detection signal is determined to be invalid, the self-capacitance detection signal is re-acquired.
  • determining the detection result according to the self-capacitance detection signal includes: when the self-capacitance detection signal is determined to be valid, if the self-capacitance detection signal is determined to be valid. If the self-capacitance detection signal is greater than a preset second threshold, it is determined that the user approaches the wearable device; wherein the second threshold is used to indicate the threshold of the self-capacitance detection signal when the user approaches the wearable device.
  • the self-capacitance variation corresponding to the first detection channel is acquired in a first period of a detection period, and the second detection channel is acquired in a second period of the detection period.
  • the mutual capacitance variation corresponding to the detection electrode of the first detection channel and the detection electrode of the second detection channel is acquired in the third period of the detection period.
  • the ESD protection device provided by this application adopts TVS, and TVS has a better electrostatic protection effect.
  • the detection circuit provided by this application can use common TVS, so as to avoid the difficulty of type selection and the high cost caused by the use of specific TVS. question.
  • the detection circuit provided by the present application can improve the accuracy of proximity detection and greatly reduce the cost of the entire detection circuit while ensuring ESD protection.
  • the proximity detection method 300 of the embodiment of the present application corresponds to the proximity detection circuit 200 of the embodiment of the present application, and the relevant description thereof may refer to the foregoing embodiments, which will not be repeated here for brevity.
  • the wearable device in the embodiment of the present application may include a device with full functions, a large size, and a device that can achieve complete or partial functions without relying on a smartphone, such as a smart watch or smart glasses; it may also include a device that only focuses on a certain A type of application function that needs to be used in conjunction with other devices such as smartphones, such as various types of smart bracelets and smart jewelry that monitor physical signs.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • Remote Sensing (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geophysics (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Electronic Switches (AREA)

Abstract

一种接近检测电路(200)，设置于可穿戴设备中，并与多个检测通道相连，接近检测电路(200)包括：自容驱动电路(210)，用于向第一检测通道输入自容驱动信号，第一检测通道上连接ESD保护电路，第一检测通道在自容驱动信号的作用下输出的自容检测信号关联于自容变化量和ESD保护电路受光照所引起的电容变化量；互容驱动电路(220)，用于向第一检测通道和第二检测通道中的一个检测通道输出互容驱动信号，在互容驱动信号的作用下，其中另一个检测通道输出的互容检测信号关联于互容变化量；及信号处理电路(215)，用于根据自容检测信号和互容检测信号确定用户是否接近可穿戴设备的检测结果。接近检测电路(200)能够提高可穿戴设备中的接近检测电路(200)的检测性能。

Description

接近检测电路、可穿戴设备和接近检测方法 技术领域
本申请实施例涉及电容检测领域，并且更具体地，涉及一种接近检测电路、可穿戴设备和接近检测方法。
背景技术
在可穿戴设备，例如真无线立体声(True Wireless Stereo，TWS)耳机中，通常利用接近检测电路来检测用户对耳机的触摸或靠近。接近检测电路可以通过检测耳机中的检测电极对地的自电容的变化情况，以获取用户接近耳机的信息，从而确定耳机的佩戴情况和使耳机执行相应的操作，例如在检测到耳机接近用户耳朵时执行播放操作，在检测到耳机离开用户耳朵时执行暂停播放的操作等。同时，为了实现电路保护，检测电极通常连接静电放电(Electrostatic Discharge，ESD)保护电路，ESD保护电路包括例如瞬态电压抑制(Transient Voltage Suppression，TVS)二极管等保护器件。TVS二极管容易受到外界光照的影响，使其对地的电容发生变化，这种电容变化会对检测电极的自电容的检测结果造成影响，从而影响接近检测电路的检测性能。
发明内容
本申请实施例提供一种接近检测电路、可穿戴设备和接近检测方法，能够提高可穿戴设备中的接近检测电路的检测性能。
第一方面，提供了一种接近检测电路，设置于可穿戴设备中，所述接近检测电路与所述可穿戴设备中的若干个检测通道相连，所述若干个检测通道中的至少部分检测通道上连接有ESD保护电路，所述接近检测电路包括：自容驱动电路，用于向所述若干个检测通道中待检测的第一检测通道输入自容驱动信号，所述第一检测通道上连接有所述ESD保护电路，所述第一检测通道在所述自容驱动信号的作用下输出的自容检测信号，关联于所述第一检测通道的检测电极的自电容相对于自容基础电容的自容变化量以及所述ESD保护电路受光照所引起的电容变化量，所述自容基础电容包括：没有用户接近所述第一检测通道的检测电极且所述ESD保护电路没有受到光照时，所述第一检测通道的检测电极的自电容；互容驱动电路，用于向所述第一检 测通道和第二检测通道中的一个检测通道输出互容驱动信号，其中，在所述互容驱动信号的作用下，所述第一检测通道和所述第二检测通道中的另一个检测通道输出的互容检测信号，关联于互容变化量，所述互容变化量为所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容相对于互容基础电容的互容变化量，所述互容基础电容包括：没有用户接近所述第一检测通道的检测电极和所述第二检测通道的检测电极时，所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容；及信号处理电路，用于根据所述自容检测信号和所述互容检测信号确定用户是否接近所述可穿戴设备的检测结果。
检测通道上连接的ESD保护电路中的ESD保护器件在受光照时，其电容也会发生变化，导致该检测通道上的检测电极的自容检测结果受到影响。在该实施例中，接近检测电路既会对检测电极进行自容检测，也会对检测电极进行互容检测，而由于互容检测基本不会受到ESD保护器件的电容变化的影响，因此基于互容检测和自容检测的检测信号共同确定最终的检测结果，可以有效提高检测结果的准确性，提高接近检测电路的检测性能。
在一种可能的实现方式中，所述互容检测信号用于判断所述自容检测信号是否有效。
具体来说，互电容检测时输出的互容检测信号可以用来判断自电容检测时输出的自容检测信号是否有效，即将互容检测信号作为辅助，来判断自容检测信号的有效性。由于互容检测基本不会受到ESD保护器件的电容变化的影响，基于互容检测信号来判断自电容检测时输出的自容检测信号的有效性，可以确保自容检测信号是由用户接近可穿戴设备引起的，从而能够提高检测结果的准确性。
在一种可能的实现方式中，当所述互容检测信号大于预设的第一阈值时，所述自容检测信号被判断为有效；和/或，当所述互容检测信号小于所述第一阈值时，所述自容检测信号被判断为无效。所述第一阈值用于指示用户接近所述可穿戴设备时的互容检测信号的阈值。
该阈值可以根据用户接近检测电极时互容检测信号的值确定。例如，可以是用户接近检测电极时互容检测信号的值的0.2-0.8倍。当互容检测信号小于该阈值时，此时可能并没有用户的接近，那么自容检测信号可以被认为是无效的，因为自容检测信号的大小很有可能反映的是ESD保护电路中的 TVS二极管受光照影响而产生的电容变化量；当互容检测信号大于该阈值时，可以认为此时用户接近了检测电极，那么自容检测信号可以被认为是有效的。
在一种可能的实现方式中，所述自容检测信号被判断为有效时，所述自容检测信号用于确定所述检测结果；和/或，所述自容检测信号被判断为无效时，所述接近检测电路重新获取所述自容检测信号。
具体来说，自容检测信号被认为是有效的，可以基于自容检测信号确定检测结果；如果自容检测信号被认为是无效的，则可以重新获取该自容检测信号，或者也可以基于互容检测信号确定检测结果。这样可以排除掉由ESD保护器件的电容变化引起的自容检测信号，从而能够提高检测结果的准确性。
在一种可能的实现方式中，所述信号处理电路用于：所述自容检测信号被判断为有效时，若所述自容检测信号大于预设的第二阈值，确定用户接近所述可穿戴设备；其中，所述第二阈值用于指示用户接近所述可穿戴设备时的自容检测信号的阈值。
自容检测信号被判断为有效，表明自容检测信号不是由ESD保护器件的电容变化引起的，此时，若自容检测信号大于预设的第二阈值，表明有用户接近了可穿戴设备。相应地，此时得到的检测结果是准确的。因此，采用上述方式，可以确保检测结果的准确性。
在一种可能的实现方式中，所述接近检测电路的一个检测周期包括第一时段、第二时段和第三时段，其中，所述第一时段用于获取所述第一检测通道对应的所述自容变化量，所述第二时段用于获取所述第二检测通道对应的所述自容变化量，所述第三时段用于获取所述第一检测通道的检测电极与所述第二检测通道的检测电极之间对应的所述互容变化量。
在该实施例中，接近检测电路的一个检测周期包括自容检测的时段，并且还包括互容检测的时段，接近检测电路按照该时序进行电容检测，可以有效获取自容检测信号和互容检测信号。
在一种可能的实现方式中，所述第二检测通道上连接有所述ESD保护电路，或者所述第二检测通道上未连接所述ESD保护电路。
在一种可能的实现方式中，所述ESD保护电路包括瞬变电压抑制TVS二极管。
在一种可能的实现方式中，所述接近检测电路还包括：多路选择器，与所述若干个检测通道、所述自容驱动电路和所述互容驱动电路分别相连，用 于将所述若干个检测通道中待检测的检测通道电连接到所述自容驱动电路或所述互容驱动电路。
在一种可能的实现方式中，所述信号处理电路包括：模拟前端AFE电路，与所述多路选择器相连，用于接收所述自容检测信号和所述互容检测信号，并对所述自容检测信号和所述互容检测信号进行信号处理以提高所述自容检测信号和所述互容检测信号的信号质量。
在一种可能的实现方式中，所述信号处理电路包括：DAQ，用于采集所述自容检测信号和所述互容检测信号；以及，DSP电路，与所述DAQ电路相连，用于根据所述自容检测信号和所述互容检测信号确定所述检测结果。
第二方面，提供了一种可穿戴设备，包括第一方面或第一方面的任意可能的实现方式中的接近检测电路。
第三方面，提供了一种接近检测方法，包括：向可穿戴设备中的待检测的第一检测通道输入自容驱动信号，其中，所述第一检测通道上连接有静电放电ESD保护电路；获取所述第一检测通道在所述自容驱动信号的作用下输出的自容检测信号，所述自容检测信号关联于所述第一检测通道的检测电极的自电容相对于自容基础电容的自容变化量以及所述ESD保护电路受光照所引起的电容变化量，所述自容基础电容包括：没有用户接近所述第一检测通道的检测电极且所述ESD保护电路没有受到光照时，所述第一检测通道的检测电极的自电容；向所述第一检测通道和第二检测通道中的一个检测通道输出互容驱动信号；获取在所述互容驱动信号的作用下，所述第一检测通道和所述第二检测通道中的另一个检测通道输出的互容检测信号，所述互容检测信号关联于互容变化量，所述互容变化量为所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容相对于互容基础电容的互容变化量，所述互容基础电容包括：没有用户接近所述第一检测通道的检测电极和所述第二检测通道的检测电极时，所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容；根据所述自容检测信号和所述互容检测信号确定用户是否接近所述可穿戴设备的检测结果。
在一种可能的实现方式中，所述根据所述自容检测信号和所述互容检测信号确定用户是否接近所述可穿戴设备的检测结果，包括：根据所述互容检测信号判断所述自容检测信号是否有效；所述自容检测信号被判断为有效时，根据所述自容检测信号确定所述检测结果。
在一种可能的实现方式中，所述根据所述互容检测信号判断所述自容检测信号是否有效，包括：当所述互容检测信号大于预设的第一阈值时，判断所述自容检测信号为有效；和/或，当所述互容检测信号小于所述第一阈值时，判断所述自容检测信号为无效；其中，所述第一阈值用于指示用户接近所述可穿戴设备时的互容检测信号的阈值。
在一种可能的实现方式中，所述方法还包括：所述自容检测信号被判断为无效时，重新获取所述自容检测信号。
在一种可能的实现方式中，所述自容检测信号被判断为有效时，根据所述自容检测信号确定所述检测结果，包括：所述自容检测信号被判断为有效时，若所述自容检测信号大于预设的第二阈值，确定用户接近所述可穿戴设备；其中，所述第二阈值用于指示用户接近所述可穿戴设备时的自容检测信号的阈值。
在一种可能的实现方式中，在一个检测周期的第一时段获取所述第一检测通道对应的所述自容变化量，在所述检测周期的第二时段获取所述第二检测通道对应的所述自容变化量，在所述检测周期的第三时段获取所述第一检测通道的检测电极与所述第二检测通道的检测电极之间对应的所述互容变化量。
附图说明
图1是本申请实施例的接近检测电路的示意性框图。
图2是基于图1所示的接近检测电路的一种可能的实现方式的示意图。
图3是本申请实施例的接近检测方法的示意性流程图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
在可穿戴设备，例如蓝牙耳机、智能手表中，通常利用接近检测电路来检测用户对可穿戴设备的触摸或靠近。比如，接近检测电路可以通过检测耳机中的检测电极的自电容的变化情况，来确定用户当前是否佩戴耳机。为了提高电容检测的可靠性，检测电极通常连接外部的ESD保护电路。本申请对ESD保护电路不做任何限定，其可以是由任何ESD保护器件形成的保护电路。以下，均以ESD保护电路包括TVS二极管为例进行描述。
可穿戴设备中一般包括若干个检测通道，例如两个或者十几个检测通道，通常，接近检测电路通过检测各个检测通道上的检测电极对地的自电容的变化情况，确定用户是否接近所述可穿戴设备的检测结果，从而使可穿戴设备根据检测结果执行相匹配的操作。上述“接近”可以包括接触或靠近。例如在检测到耳机接近用户的耳朵时执行播放操作，在检测到耳机离开用户的耳朵时执行暂停播放的操作等。例如，在上述自电容的电容变化量达到预设阈值时，会认为耳机被佩戴在用户耳朵上，进而耳机开始播放音乐。该阈值可以是用于指示用户接近可穿戴设备时的电容变化量的阈值。
连接在检测通道上的TVS二极管与地之间也会存在电容，也称TVS二极管的结电容。但是，TVS二极管容易受到外界光照的影响，而使其对地的电容随光照而发生变化，这种电容变化会对检测电极的自电容的检测结果造成影响，从而影响检测结果。
图1是本申请实施例的接近检测电路的示意性框图。图2是基于图1所示的接近检测电路的一种可能的实现方式的示意图。下面先结合图2说明上述问题。如图2所示，接近检测电路200与检测通道C 0至检测通道C N连接，下面以检测通道C 0和检测通道C 1为例进行说明，图2中仅示出检测通道C 0和检测通道C 1这两条支路上的电路结构。如图2所示，检测通道C 0和检测通道C 1上分别连接TVS二极管D 0和TVS二极管D 1。检测通道C 0上的检测电极S 0对地的自电容为C S0，检测通道C 1上的检测电极S 1对地的自电容为C S1。当用户接近检测电极S 0时，检测电极S 0的自电容C S0的大小会发生变化，自电容C S0的电容变化量为△C S0body。该自容变化量△C S0body是接近检测电路200所期望检测到的有效数据。但是，在受到光照时，检测通道C 0上连接的TVS二极管D 0对地的电容C j0也会发生变化，电容变化量为△C j0。这样，检测通道C 0上输出的检测信号所反映的电容的变化量，就包括△C S0body和△C j0。接近检测电路200会误认为△C S0body和△C j0这两部分的电容变化量是有效数据，从而根据△C S0body和△C j0确定检测通道C 0的检测结果，即用户是否接近检测电极S 0的检测结果。
类似地，当用户接近检测电极S 1对应的位置时，检测电极S 1的自电容C S1的大小会发生变化，自电容C S1的电容变化量为△C S1body。该自容变化量△C S1body是接近检测电路200所期望检测到的有效数据。但是，在受到光照时，检测通道C 1上连接的TVS二极管D 1对地的电容C j1也会发生变化，电 容变化量为△C j1。这样，检测通道C 1上输出的检测信号所反映的电容的变化量，就包括△C S1body和△C j1。接近检测电路200会误认为△C S1body和△C j1这两部分电容变化量是有效数据，从而根据△C S1body和△C j1确定检测通道C 1的检测结果，即用户是否接近检测电极S 1的检测结果。
正因如此，在实际应用中，一方面，当可穿戴设备受到一定光照时，即使没有发生用户接近可穿戴设备的事件，可穿戴设备也可能会检测到上述自电容的电容变化量达到阈值，会认为可穿戴设备被佩戴在用户身上，进而开始播放音乐等响应事件；另一方面，可穿戴设备在正常响应用户接近可穿戴设备的事件后，由于光照的影响，当可穿戴设备实际已经远离用户时，也可能可穿戴设备被误识别为依然佩戴在用户身上，进而可穿戴设备无法正常退出上述响应事件。
以耳机为例，假设，图2中的检测通道C 0上的检测电极S 0的自容变化量△C S0body大于阈值A时，认为用户佩戴该耳机，从而该耳机执行播放操作；而△C S0body小于阈值A时，认为用户摘掉该耳机，从而该耳机执行暂停播放的操作。当存在光照时，如果用户没有佩戴该耳机，但是因光照而使TVS二极管D 0的电容变化量△C j0大于该阈值A，那么耳机也会执行播放操作，从而产生误响应。当存在光照时，如果用户摘掉耳机，但是因光照而使TVS二极管D 0的电容变化量△C j0大于该阈值A，那么耳机并不会认为用户摘掉耳机了，而是继续播放，无法正常退出。
可见，作为ESD保护电路的TVS二极管(或其它的会受光照影响电容的ESD保护器件)因光照而产生的电容的变化，会对电容检测的结果造成影响，从而影响接近检测电路的检测性能。对于此，一种解决方案是选择合适的、结电容基本不受光照影响的ESD保护二极管，然而，这又会导致选择ESD保护器件的难度大且成本高的问题。
为此，本申请实施例提供一种接近检测电路，通过在自容检测的基础上增加互容检测作为辅助，以降低ESD保护电路因光照而对自容检测造成的影响，并提高接近检测电路的电容检测结果的准确性，进而减少对人体接近可穿戴设备的事件的误判。
图1是本申请实施例的接近检测电路200的示意性框图。接近检测电路200可以应用于可穿戴设备中，该可穿戴设备包括但不限于TWS耳机(包括入耳式、半入耳式和头戴式等)、智能手表、智能眼镜等智能穿戴设备。
接近检测电路200与可穿戴设备中的若干个检测通道相连，该若干个检测通道中的至少部分检测通道上连接有ESD保护电路，该ESD保护电路包括TVS二极管。如图2所示，接近检测电路200包括自容驱动电路210、互容驱动电路220和信号处理电路215。
其中，自容驱动电路210用于向该若干个检测通道中待检测的第一检测通道输入自容驱动信号，第一检测通道上连接有ESD保护电路。
该第一检测通道在该自容驱动信号的作用下输出的自容检测信号，关联于该第一检测通道的检测电极的自电容相对于自容基础电容的自容变化量，以及ESD保护电路受光照所引起的电容变化量。
互容驱动电路220用于向该第一检测通道和第二检测通道中的一个检测通道输出互容驱动信号。该第二检测通道可以是与该第一检测通道形成互容检测的任一检测通道。
在该互容驱动信号的作用下，该第一检测通道和该第二检测通道中的另一个检测通道输出的互容检测信号，关联于该第一检测通道的检测电极与该第二检测通道的检测电极之间的互电容相对于互容基础电容的互容变化量。
信号处理电路215用于根据该自容检测信号和该互容检测信号确定用户是否接近所述可穿戴设备的检测结果。
检测通道上连接的ESD保护电路中的ESD保护器件在光照时，ESD保护器件的结电容也会发生变化，导致该检测通道上的检测电极的自容检测结果受到影响。在本申请实施例中，接近检测电路200除了对检测电极进行自容检测，还会对检测电极进行互容检测，而由于互容检测基本不会受到ESD保护器件的电容变化的影响，因此基于互容检测和自容检测的检测信号共同确定最终的检测结果，可以有效提高检测结果的准确性，提高接近检测电路的检测性能。而且，本申请提供的检测电路可以采用普通的ESD保护器件，依然可以在保障ESD防护的同时，提高接近检测的准确性且能减少对ESD器件选型的要求及降低使用特定的ESD器件带来的成本的影响。
通常，可穿戴设备中的接近检测电路的自容检测比互容检测能够适应更远的检测距离。以耳机为例，由于人体耳朵内的空间大小不同，戴入耳机后，耳机的检测电极的位置与耳朵的贴合程度就不同，可能完全贴合，也可能存在一定距离(比如手旋转耳机或人运动导致耳机松动)。对于自容检测而言，其能够适应的检测距离更大，而互容检测能够适应的检测距离更小。因此， 对于耳机这类可穿戴设备而言，主要采用自容检测的方式检测用户的接近。
然而，检测通道上连接的ESD保护电路中的ESD保护器件在光照时，其电容也会发生变化，导致检测通道上的检测电极的自容检测结果受到影响。因此，本申请实施例中，接近检测电路通过互容检测的结果，来辅助判断自容检测的结果，从而提高检测结果的准确性，减少对用户接近的事件的误判。
本申请实施例对ESD保护电路不做限定。优选地，ESD保护电路中可以采用TVS二极管作为ESD保护器件。以下，均以TVS二极管作为ESD保护器件为例进行描述。这时，前述的自容检测信号不仅关联于第一检测通道的检测电极的自容变化量，还关联于该TVS二极管因光照所引起的电容变化量。
并非所有检测通道上都需要连接ESD保护电路，为了节省成本和空间，可以只在部分检测通道上连接ESD保护电路，例如，在第一检测通道和第二检测通道中，可以仅在其中一个检测通道上连接ESD保护电路，也可以在两个检测通道上都连接ESD保护电路。在具体实现时，例如可以通过对各个检测通道进行静电测试，找到容易受到静电影响的检测通道，并在这些检测通道上连接ESD保护电路，而不易受到静电影响的检测通道上可以不连接ESD保护电路。
本申请实施例对检测通道上的检测电极的形状和大小不做限定。
接近检测电路200对第一检测通道进行自容检测时，检测的是第一检测通道的检测电极与地之间的自电容相对于自容基础电容的变化量；而在进行互容检测时，检测的是第一检测通道的检测电极与第二检测通道的检测电极之间的互电容相对于互容基础电容的变化量。应理解，关于电容变化量的检测，可以是直接测得该变化量，也可以是间接得到该变化量，即先测得检测值，再根据检测值与基础值得到该变化量。TVS二极管接地，用以将发生静电时产生的静电电荷转移至地，TVS二极管受光照时产生的电容变化量对自容检测的结果会造成影响。互容检测时的回路经过两个检测电极之间，因此，TVS二极管受光照时产生的电容变化量基本不会对互容检测的结果造成影响。
其中，上述的自容基础电容包括：没有用户接近该第一检测通道且该第一检测通道上连接的TVS二极管没有受到光照时，该第一检测通道的检测电极的自电容。
当有用户接近该第一检测通道或者该TVS二极管受到光照时，在该自容基础电容的基础上，第一检测通道对应的自电容会发生变化，根据自容变化量的大小，就可以确定用户是否接近第一检测通道对应的位置。
其中，上述的互容基础电容包括：没有用户接近该第一检测通道和该第二检测通道，且该TVS二极管没有受到光照时，该第一检测通道的检测电极与该第二检测通道的检测电极之间的互电容。
当有用户接近该第一检测电极、第二检测电极、或者该TVS二极管受到光照时，在该互容基础电容的基础上，第一检测通道对应的互电容会发生变化，根据互容变化量的大小，就可以确定用户是否接近第一检测通道或第二检测通道对应的位置。
接近检测电路200在进行自容检测时获得的自容检测信号，以及在进行互容检测时获得的互容检测信号，共同用于确定检测结果。
例如，该互容检测信号可以用于判断该自容检测信号是否有效。可选地，当该互容检测信号大于预设的第一阈值时，该自容检测信号被判断为有效；和/或，当该互容检测信号小于所述第一阈值时，该自容检测信号被判断为无效。该第一阈值用于指示用户接近可穿戴设备时的互容检测信号的阈值。
该第一阈值可以根据具体的产品形态来设定，对于TWS而言，该第一阈值例如可以是几十fF至几百fF。
由于互容检测基本不会受到ESD保护器件的电容变化的影响，基于互容检测信号来判断自电容检测时输出的自容检测信号的有效性，可以确保自容检测信号是由用户接近可穿戴设备引起的，从而能够提高检测结果的准确性。
进一步地，可选地，自容检测信号被判断为有效时，该自容检测信号用于确定检测结果；和/或，自容检测信号被判断为无效时，该接近检测电路重新获取该自容检测信号。
也就是说，如果自容检测信号被认为是有效的，可以基于自容检测信号确定检测结果；如果自容检测信号被认为是无效的，则可以重新获取该自容检测信号，或者也可以基于互容检测信号确定检测结果。这样可以排除掉由ESD保护器件的电容变化引起的自容检测信号，从而能够提高检测结果的准确性。
可选地，所述自容检测信号被判断为有效时，若所述自容检测信号大于 预设的第二阈值，确定用户接近所述可穿戴设备；其中，所述第二阈值用于指示用户接近所述可穿戴设备时的自容检测信号的阈值。
自容检测信号被判断为有效，表明自容检测信号不是由ESD保护器件的电容变化引起的，此时，若自容检测信号大于预设的第二阈值，表明有用户接近了可穿戴设备。相应地，此时得到的检测结果是准确的。因此，采用上述方式，可以确保检测结果的准确性。
图2是基于图1所示的接近检测电路200的一种可能的实现方式的示意图。如图2所示，接近检测电路200与检测通道C 0至检测通道C N连接，下面以检测通道C 0和检测通道C 1为例进行说明，图2中仅示出检测通道C 0和检测通道C 1这两条支路上的电路结构。如图2所示，检测通道C 0和检测通道C 1上分别连接TVS二极管D 0和TVS二极管D 1。参见表一，检测通道C 0上的检测电极S 0对地的自电容为C S0，检测通道C 1上的检测电极S 1对地的自电容为C S1，检测通道C 0上的检测电极S 0与检测通道C 1上的检测电极S 1之间的互电容为C m，TVS二极管D 0对地的电容和TVS二极管D 1对地的电容分别为C j0和C j1。
在没有光照时，且没有用户接近第一检测通道和第二检测通道对应的位置时，C S0、C S1、C m、C j0、C j1分别为C S0＝C S0base、C S1＝C S1base、C m＝C mbase、C j0＝C j0base、C j1＝C j1base。当有用户接近第一检测通道和第二检测通道对应的位置时，C S0、C S1、C m分别为C S0＝C S0base+△C S0body、C S1＝C S1base+△C S1body、C m＝C mbase+△C mbody，即变化量分别为△C S0body、△C S1body和△C mbody。当受到光照时，C j0、C j1分别为C j0＝C j0base+△C j0、C j1＝C j1base+△C j1，即变化量分别为△C j0和△C j1。从表一可以看出，接近检测电路200所期望检测到的有效数据是△C S0body、△C S1body和△C mbody，但是实际检测到的信号受到了C j0和△C j1的影响。△C j0和△C j1仅对自容检测的结果有影响，而对互容检测的结果没有影响。
表一
Figure PCTCN2020141618-appb-000001
Figure PCTCN2020141618-appb-000002
图2所示的接近检测电路200在进行接近检测时，自容驱动电路210可以向检测通道C 0输入自容驱动信号，并接收检测通道C 0输出的自容检测信号，自容检测信号反映的是检测电极C S0的自容变化量△C S0body以及TVS二极管的电容变化量△C j0；互容驱动电路220可以向检测通道C 0和检测通道C 1中的其中一个检测通道输入互容驱动信号，并接收其中另一个检测通道输出的互容检测信号，自容检测信号反映的是检测电极C S0和检测电极C S1之间的互容变化量△C mbody。设定阈值B，互容检测信号如果大于阈值B，则认为自容检测信号是有效的，接近检测电路200可以根据自容检测信号判断用户是否接近第一检测通道对应的位置；如果互容检测信号小于阈值B，则认为自容检测信号是无效的，这时，接近检测电路200可以重新获取该自容检测信号。
以耳机为例，假设，图2中的检测通道C 0上的检测电极S 0的自容变化量△C S0body大于阈值A时，认为用户佩戴该耳机，从而该耳机执行播放操作；而△C S0body小于阈值A时，认为用户摘掉该耳机，从而该耳机执行暂停播放的操作。
当存在光照时，如果用户没有佩戴该耳机，但是因光照而使TVS二极管D 0的电容变化量△C j0大于阈值A，耳机也会执行播放操作，从而产生误响应。此时，如果用于表示互容变化量△C mbody的互容检测信号小于阈值B，则会判断上述的检测结果无效，从而不会使耳机误播放；如果互容检测信号大于阈值B，则会判断上述的检测结果有效，从而执行播放。
当存在光照时，如果用户摘掉耳机，但是因光照而使TVS二极管D 0的电容变化量△C j0大于阈值A，那么并不会认为用户摘掉耳机了，从而继续播放，无法退出。此时，如果用于表示互容变化量△C mbody的互容检测信号小于阈值B，则会判断上述的检测结果无效，从而不会使耳机误播放；如果互容检测信号大于阈值B，则会判断上述的检测结果有效，从而继续执行播放。
本申请实施例中，接近检测电路200的一个检测周期中包括第一时段、第二时段和第三时段。这三个时段分别用于第一检测通道的自容检测、第二检测通道的自容检测、以及第一检测通道和第二检测通道之间的互容检测。 这里对第一时段、第二时段和第三时段在时间上的先后顺序不做限定。
例如，该检测周期中按照时间先后分别包括第一时段、第二时段和第三时段。其中，第一时段用于获取第一检测通道对应的自容变化量，第二时段用于获取第二检测通道对应的自容变化量，第三时段用于获取第一检测通道的检测电极与第二检测通道的检测电极之间对应的互容变化量。完成一次检测后，可以根据自容检测和互容检测的数据，综合确定对第一检测通道和第二检测通道的检测结果。这样，在一个检测周期内就可以得到相应检测通道的准确的检测结果。
在对若干个检测通道进行检测时，可以是串行检测也可以是并行检测。为了提高可操作性，优选地，通常采用串行检测的方式。如图2所示，在一个检测周期中，对检测通道C 0上的检测电极的自容变化量和检测通道C 1上的检测电极的自容变化量进行检测，并对二者之间的互容变化量进行检测；接着，在下一个检测周期中，对检测通道C 2上的检测电极的自容变化量和检测通道C 3上的检测电极的自容变化量进行检测，并对二者之间的互容变化量进行检测；依次，类似地，在后续的检测周期中按照顺序对剩余的检测通道进行检测，直至最终对检测通道C N-1上的检测电极的自容变化量和检测通道C N上的检测电极的自容变化量进行检测，并对二者之间的互容变化量进行检测。
可选地，如图2所示，接近检测电路200还可以包括多路选择器230。多路选择器230与可穿戴设备中的若干个检测通道、自容驱动电路210和互容驱动电路220相连，并用于将若干个检测通道中待检测的检测通道电连接到所述自容驱动电路210或所述互容驱动电路220。
进一步地，信号处理电路215可以包括模拟前端(Analog Front End，AFE)电路240。AFE电路240与多路选择器230相连，用于接收自容检测信号和互容检测信号，并对自容检测信号和互容检测信号进行信号调理以提高自容检测信号和互容检测信号的信号质量。
进一步地，信号处理电路215可以包括数据采集电路(Data Acquisition Circuit，DAQ)250和数字信号处理电路(Digital Signal Processor，DSP)260。
DAQ 250用于采集自容检测信号和互容检测信号。例如，DAQ 250可以与AFE电路240相连，用于采集经过AFE电路240处理后的自容检测信号和互容检测信号。DSP电路260与DAQ电路250相连，用于根据自容检 测信号和互容检测信号确定检测结果。
多路选择器(Multiplexer)230也可以称为多路复用器、数据选择器等，是一种可以从多个信号中选择一个信号进行输入或输出的器件。其具体描述可参考相关技术中对多路选择器的描述，此处不再赘述。任何一个检测通道都可以通过多路选择器230切换连接至自容驱动电路210、互容驱动电路220和AFE电路240。
例如，当前检测的是第一检测通道的检测电极对地的自电容，那么多路选择器230可以在若干个检测通道中，选通第一检测通道，从而使自容驱动电路210的驱动信号可以被输入至第一检测通道，并使第一检测通道输出的自容检测信号可以通过多路选择器230输出至AFE电路240中。
又例如，当前检测的是第二检测通道的检测电极对地的自电容，那么多路选择器230可以在若干个检测通道中，选通第二检测通道，从而使自容驱动电路210的驱动信号可以被输入至第二检测通道，并使第二检测通道输出的自容检测信号可以通过多路选择器230输出至AFE电路240中。
又例如，当前检测的是第一检测通道的检测电极和第二检测通道的检测电极之间的互电容，那么多路选择器230可以在若干个检测通道中，选通第一检测通道和第二检测通道，从而使自容驱动电路210的驱动信号被输入至第一检测通道，并使第二检测通道输出的互容检测信号通过多路选择器230输出至AFE电路240中；或者使自容驱动电路210的驱动信号被输入至第二检测通道，并使第一检测通道输出的互容检测信号通过多路选择器230输出至AFE电路240中。
AFE电路240是包括放大电路、滤波电路、模数转换电路等在内的集成组件，可以用来对自容检测信号和互容检测信号进行放大、滤波、信号转换等操作。本申请实施例对AFE电路240的具体结构不做限定。其具体描述可参考相关技术中对AFE电路的描述，此处不再赘述。
此外，接近检测电路200还可以包括其他电路组件，例如辅助电路、供电电路等，此处不再示意。
接近检测电路200可以是集成电路，即上述的各个电路模块210至260可以集成在一个芯片上；或者，上述的各个电路模块210至260也可以是分立的电路模块。本申请实施例对此不做限定。
本申请实施例还提供一种可穿戴设备，包括上述本申请各种实施例中的 接近检测电路200。
本申请实施例还提供了一种接近检测方法300。该方法可以应用于上述本申请各种实施例中的接近检测电路200和可穿戴设备。如图3所示，该方法300可以包括：
310，向可穿戴设备中的待检测的第一检测通道输入自容驱动信号，其中，所述第一检测通道上连接有静电放电ESD保护电路；
320，获取所述第一检测通道在所述自容驱动信号的作用下输出的自容检测信号，所述自容检测信号关联于所述第一检测通道的检测电极的自电容相对于自容基础电容的自容变化量以及所述ESD保护电路受光照所引起的电容变化量，所述自容基础电容包括：没有用户接近所述第一检测通道的检测电极且所述ESD保护电路没有受到光照时，所述第一检测通道的检测电极的自电容；
330，向所述第一检测通道和第二检测通道中的一个检测通道输出互容驱动信号；
340，获取在所述互容驱动信号的作用下，所述第一检测通道和所述第二检测通道中的另一个检测通道输出的互容检测信号，所述互容检测信号关联于互容变化量，所述互容变化量为所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容相对于互容基础电容的互容变化量，所述互容基础电容包括：没有用户接近所述第一检测通道的检测电极和所述第二检测通道的检测电极时，所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容；
350，根据所述自容检测信号和所述互容检测信号确定用户是否接近所述可穿戴设备的检测结果。
可选地，在一个实施例中，可以根据所述互容检测信号判断所述自容检测信号是否有效；所述自容检测信号被判断为有效时，根据所述自容检测信号确定所述检测结果。
可选地，在一个实施例中，当所述互容检测信号大于预设的第一阈值时，判断所述自容检测信号为有效；和/或，当所述互容检测信号小于所述第一阈值时，判断所述自容检测信号为无效；其中，所述第一阈值用于指示用户接近所述可穿戴设备时的互容检测信号的阈值。
可选地，在一个实施例中，所述自容检测信号被判断为无效时，重新获 取所述自容检测信号。
可选地，在一个实施例中，所述自容检测信号被判断为有效时，根据所述自容检测信号确定所述检测结果，包括：所述自容检测信号被判断为有效时，若所述自容检测信号大于预设的第二阈值，确定用户接近所述可穿戴设备；其中，所述第二阈值用于指示用户接近所述可穿戴设备时的自容检测信号的阈值。
可选地，在一个实施例中，在一个检测周期的第一时段获取所述第一检测通道对应的所述自容变化量，在所述检测周期的第二时段获取所述第二检测通道对应的所述自容变化量，在所述检测周期的第三时段获取所述第一检测通道的检测电极与所述第二检测通道的检测电极之间对应的所述互容变化量。
优选地，本申请提供的ESD保护器件采用TVS，TVS的静电保护效果较好，本申请提供的检测电路可以采用普通的TVS，以避免采用特定的TVS带来的选型困难及成本较高的问题。本申请提供的检测电路可以在保障ESD防护的同时，提高接近检测的准确性且能大大减少整个检测电路的成本。
应理解，本申请实施例的接近检测方法300与本申请实施例的接近检测电路200对应，其中的相关描述可以参考前述各实施例，为了简洁，在此不再赘述。
作为示例而非限定，本申请实施例中的可穿戴设备可以包括功能全、尺寸大、可不依赖智能手机实现完整或部分功能的设备，例如智能手表或智能眼镜等；也可以包括只专注于某一类应用功能，且需要和其它设备例如智能手机等配合使用的设备，例如各类进行体征监测的智能手环、智能首饰等。
需要说明的是，在不冲突的前提下，本申请描述的各个实施例和/或各个实施例中的技术特征可以任意的相互组合，组合之后得到的技术方案也应落入本申请的保护范围。
应理解，本申请实施例中的具体的例子只是为了帮助本领域技术人员更好地理解本申请实施例，而非限制本申请实施例的范围，本领域技术人员可以在上述实施例的基础上进行各种改进和变形，而这些改进或者变形均落在本申请的保护范围内。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易 想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (17)

  1. 一种接近检测电路，其特征在于，设置于可穿戴设备中，所述接近检测电路与所述可穿戴设备中的若干个检测通道相连，所述若干个检测通道中的至少部分检测通道上连接有静电放电ESD保护电路，所述接近检测电路包括：
    自容驱动电路，用于向所述若干个检测通道中待检测的第一检测通道输入自容驱动信号，所述第一检测通道上连接有所述ESD保护电路，所述第一检测通道在所述自容驱动信号的作用下输出的自容检测信号，关联于所述第一检测通道的检测电极的自电容相对于自容基础电容的自容变化量以及所述ESD保护电路受光照所引起的电容变化量，所述自容基础电容包括：没有用户接近所述第一检测通道的检测电极且所述ESD保护电路没有受到光照时，所述第一检测通道的检测电极的自电容；
    互容驱动电路，用于向所述第一检测通道和第二检测通道中的一个检测通道输出互容驱动信号，其中，在所述互容驱动信号的作用下，所述第一检测通道和所述第二检测通道中的另一个检测通道输出的互容检测信号，关联于互容变化量，所述互容变化量为所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容相对于互容基础电容的互容变化量，所述互容基础电容包括：没有用户接近所述第一检测通道的检测电极和所述第二检测通道的检测电极时，所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容；及
    信号处理电路，用于根据所述自容检测信号和所述互容检测信号确定用户是否接近所述可穿戴设备的检测结果。
  2. 根据权利要求1所述接近检测电路，其特征在于，所述互容检测信号用于判断所述自容检测信号是否有效。
  3. 根据权利要求2所述的接近检测电路，其特征在于，
    当所述互容检测信号大于预设的第一阈值时，所述自容检测信号被判断为有效；和/或，
    当所述互容检测信号小于所述第一阈值时，所述自容检测信号被判断为无效；
    其中，所述第一阈值用于指示用户接近所述可穿戴设备时的互容检测信号的阈值。
  4. 根据权利要求2或3所述的接近检测电路，其特征在于，
    所述自容检测信号被判断为有效时，所述自容检测信号用于确定所述检测结果；和/或，
    所述自容检测信号被判断为无效时，所述接近检测电路重新获取所述自容检测信号。
  5. 根据权利要求4所述的接近检测电路，其特征在于，所述信号处理电路用于：
    所述自容检测信号被判断为有效时，若所述自容检测信号大于预设的第二阈值，确定用户接近所述可穿戴设备；
    其中，所述第二阈值用于指示用户接近所述可穿戴设备时的自容检测信号的阈值。
  6. 根据权利要求1至5中任一项所述的接近检测电路，其特征在于，所述接近检测电路的一个检测周期包括第一时段、第二时段和第三时段，其中，所述第一时段用于获取所述第一检测通道对应的所述自容变化量，所述第二时段用于获取所述第二检测通道对应的所述自容变化量，所述第三时段用于获取所述第一检测通道的检测电极与所述第二检测通道的检测电极之间对应的所述互容变化量。
  7. 根据权利要求1至6中任一项所述的接近检测电路，其特征在于，所述ESD保护电路包括瞬变电压抑制TVS二极管。
  8. 根据权利要求1至7中任一项所述的接近检测电路，其特征在于，所述接近检测电路还包括：
    多路选择器，与所述若干个检测通道、所述自容驱动电路和所述互容驱动电路相连，用于将所述若干个检测通道中待检测的检测通道电连接到所述自容驱动电路或所述互容驱动电路。
  9. 根据权利要求8所述的接近检测电路，其特征在于，所述信号处理电路包括：
    数据采集电路DAQ，用于采集所述自容检测信号和所述互容检测信号；以及，
    数字信号处理电路DSP，与所述DAQ相连，用于根据所述自容检测信号和所述互容检测信号确定所述检测结果。
  10. 根据权利要求1至9中任一项所述的接近检测电路，其特征在于， 所述可穿戴设备包括真无线立体声TWS耳机、智能手表或者智能眼镜。
  11. 一种可穿戴设备，其特征在于，包括上述权利要求1至10中任一项所述的接近检测电路。
  12. 一种接近检测方法，其特征在于，包括：
    向可穿戴设备中的待检测的第一检测通道输入自容驱动信号，其中，所述第一检测通道上连接有静电放电ESD保护电路；
    获取所述第一检测通道在所述自容驱动信号的作用下输出的自容检测信号，所述自容检测信号关联于所述第一检测通道的检测电极的自电容相对于自容基础电容的自容变化量以及所述ESD保护电路受光照所引起的电容变化量，所述自容基础电容包括：没有用户接近所述第一检测通道的检测电极且所述ESD保护电路没有受到光照时，所述第一检测通道的检测电极的自电容；
    向所述第一检测通道和第二检测通道中的一个检测通道输出互容驱动信号；
    获取在所述互容驱动信号的作用下，所述第一检测通道和所述第二检测通道中的另一个检测通道输出的互容检测信号，所述互容检测信号关联于互容变化量，所述互容变化量为所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容相对于互容基础电容的互容变化量，所述互容基础电容包括：没有用户接近所述第一检测通道的检测电极和所述第二检测通道的检测电极时，所述第一检测通道的检测电极与所述第二检测通道的检测电极之间的互电容；
    根据所述自容检测信号和所述互容检测信号确定用户是否接近所述可穿戴设备的检测结果。
  13. 根据权利要求12所述方法，其特征在于，所述根据所述自容检测信号和所述互容检测信号确定用户是否接近所述可穿戴设备的检测结果，包括：
    根据所述互容检测信号判断所述自容检测信号是否有效；
    所述自容检测信号被判断为有效时，根据所述自容检测信号确定所述检测结果。
  14. 根据权利要求13所述的方法，其特征在于，所述根据所述互容检测信号判断所述自容检测信号是否有效，包括：
    当所述互容检测信号大于预设的第一阈值时，判断所述自容检测信号为有效；和/或，
    当所述互容检测信号小于所述第一阈值时，判断所述自容检测信号为无效；
    其中，所述第一阈值用于指示用户接近所述可穿戴设备时的互容检测信号的阈值。
  15. 根据权利要求13或14所述的方法，其特征在于，所述方法还包括：
    所述自容检测信号被判断为无效时，重新获取所述自容检测信号。
  16. 根据权利要求13或14所述的方法，其特征在于，所述自容检测信号被判断为有效时，根据所述自容检测信号确定所述检测结果，包括：
    所述自容检测信号被判断为有效时，若所述自容检测信号大于预设的第二阈值，确定用户接近所述可穿戴设备；
    其中，所述第二阈值用于指示用户接近所述可穿戴设备时的自容检测信号的阈值。
  17. 根据权利要求12至16中任一项所述的方法，其特征在于，在一个检测周期的第一时段获取所述第一检测通道对应的所述自容变化量，在所述检测周期的第二时段获取所述第二检测通道对应的所述自容变化量，在所述检测周期的第三时段获取所述第一检测通道的检测电极与所述第二检测通道的检测电极之间对应的所述互容变化量。
PCT/CN2020/141618 2020-12-30 2020-12-30 接近检测电路、可穿戴设备和接近检测方法 WO2022141248A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2020/141618 WO2022141248A1 (zh) 2020-12-30 2020-12-30 接近检测电路、可穿戴设备和接近检测方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2020/141618 WO2022141248A1 (zh) 2020-12-30 2020-12-30 接近检测电路、可穿戴设备和接近检测方法

Publications (1)

Publication Number Publication Date
WO2022141248A1 true WO2022141248A1 (zh) 2022-07-07

Family

ID=82259961

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/141618 WO2022141248A1 (zh) 2020-12-30 2020-12-30 接近检测电路、可穿戴设备和接近检测方法

Country Status (1)

Country Link
WO (1) WO2022141248A1 (zh)

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4916863B2 (ja) * 2006-12-15 2012-04-18 三菱電機株式会社 近接検出装置
CN103186298A (zh) * 2011-12-29 2013-07-03 旭曜科技股份有限公司 电容式多点触控的低待机功耗驱动方法及装置
CN104615314A (zh) * 2013-11-01 2015-05-13 盛群半导体股份有限公司 电容式触控感测器及其自容与互容的切换方法
US20160224166A1 (en) * 2012-08-10 2016-08-04 Semiconductor Energy Laboratory Co., Ltd. Display device
CN106502451A (zh) * 2016-09-27 2017-03-15 北京集创北方科技股份有限公司 触摸检测方法和装置
CN109328293A (zh) * 2018-09-30 2019-02-12 深圳市汇顶科技股份有限公司 电容检测模组、方法及电子设备
CN109426380A (zh) * 2017-08-28 2019-03-05 奇景光电股份有限公司 触控装置及其感测方法与触控感测电路
WO2020028542A1 (en) * 2018-08-02 2020-02-06 Elo Touch Solutions, Inc. Water immune projected-capacitive (pcap) touchscreen
CN212031757U (zh) * 2020-09-07 2020-11-27 深圳市汇顶科技股份有限公司 接近检测装置及电子设备
CN212207517U (zh) * 2020-03-12 2020-12-22 深圳芯启航科技有限公司 自互电容检测电路、芯片及设备

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4916863B2 (ja) * 2006-12-15 2012-04-18 三菱電機株式会社 近接検出装置
CN103186298A (zh) * 2011-12-29 2013-07-03 旭曜科技股份有限公司 电容式多点触控的低待机功耗驱动方法及装置
US20160224166A1 (en) * 2012-08-10 2016-08-04 Semiconductor Energy Laboratory Co., Ltd. Display device
CN104615314A (zh) * 2013-11-01 2015-05-13 盛群半导体股份有限公司 电容式触控感测器及其自容与互容的切换方法
CN106502451A (zh) * 2016-09-27 2017-03-15 北京集创北方科技股份有限公司 触摸检测方法和装置
CN109426380A (zh) * 2017-08-28 2019-03-05 奇景光电股份有限公司 触控装置及其感测方法与触控感测电路
WO2020028542A1 (en) * 2018-08-02 2020-02-06 Elo Touch Solutions, Inc. Water immune projected-capacitive (pcap) touchscreen
CN109328293A (zh) * 2018-09-30 2019-02-12 深圳市汇顶科技股份有限公司 电容检测模组、方法及电子设备
CN212207517U (zh) * 2020-03-12 2020-12-22 深圳芯启航科技有限公司 自互电容检测电路、芯片及设备
CN212031757U (zh) * 2020-09-07 2020-11-27 深圳市汇顶科技股份有限公司 接近检测装置及电子设备

Similar Documents

Publication Publication Date Title
CN111488083B (zh) 具有自校准功能的电容式触摸检测装置
US10313777B2 (en) Earphone control circuit and method, earphone, as well as audio output device and method
US9924270B2 (en) Techniques for channelization of stereo audio in headphones
KR101646964B1 (ko) 휴대용 단말기에서 이어폰 인식 회로 장치
US10103541B2 (en) Wearable device and electrostatic discharge protection circuit of the same
TWI441070B (zh) 觸控感測裝置之感測方法
US9910178B2 (en) Accessory detection
JP5161153B2 (ja) オーディオ・デバイスの認識装置および携帯式コンピュータ
CA2760220C (en) Apparatus, systems and methods for controlling an electronic device using an accessory
US11985470B2 (en) Method and device for detecting wearing state of earphones, and earphones
WO2018062630A1 (ko) 비접촉 심전도 측정 방법, 비접촉 심전도 측정 회로 및 이를 이용한 심전도 측정 장치
WO2021187884A1 (ko) 생체 정보를 감지하는 웨어러블 전자 장치
CN113709623B (zh) 一种耳机的控制方法、装置、耳机和存储介质
WO2016053556A1 (en) Electronics interface for device headset jack
CN112305320B (zh) 接近检测电路、可穿戴设备和接近检测方法
WO2022141248A1 (zh) 接近检测电路、可穿戴设备和接近检测方法
US20110273189A1 (en) Sensing apparatus for and associated methods
TWI633795B (zh) 一種訊號處理系統及其方法
CN114003147B (zh) 信号检测装置、触控板和电子设备
CN115243145A (zh) 耳机控制方法、装置、耳机及计算机可读存储介质
CN110987154B (zh) 一种敲击事件的检测方法、装置、介质及头戴式设备
TW202143016A (zh) 近接偵測方法及其電路
US20210194481A1 (en) Dynamic capacitive sensing
TW202007044A (zh) 過電流保護裝置及方法
JP7305162B2 (ja) 音電気変換装置

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: 20967589

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: 20967589

Country of ref document: EP

Kind code of ref document: A1