WO2022141248A1

WO2022141248A1 - Proximity detection circuit, wearable device and proximity detection method

Info

Publication number: WO2022141248A1
Application number: PCT/CN2020/141618
Authority: WO
Inventors: 唐玲裕
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2022-07-07

Abstract

A proximity detection circuit (200), provided in a wearable device and connected to a plurality of detection channels. The proximity detection circuit (200) comprises: a self-capacitance drive circuit (210), configured to input a self-capacitance drive signal to a first detection channel, wherein the first detection channel is connected to an ESD protection circuit, and a self-capacitance detection signal outputted by the first detection channel under the action of the self-capacitance drive signal is associated with a self-capacitance variation amount and a capacitance variation amount caused by the ESD protection circuit being illuminated; a mutual-capacitance drive circuit (220), configured to output a mutual-capacitance drive signal to one of the first detection channel and a second detection channel, wherein under the action of the mutual-capacitance drive signal, a mutual-capacitance detection signal outputted by the other detection channel is associated with a mutual-capacitance variation amount; and a signal processing circuit (215), configured to determine, according to the self-capacitance detection signal and the mutual-capacitance detection signal, a detection result of whether a user is close to a wearable device. The proximity detection circuit (200) can improve the detection performance of the proximity detection circuit (200) in a wearable device.

Description

Proximity detection circuit, wearable device, and proximity detection method

technical field

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.

Background technique

In wearable devices, such as True Wireless Stereo (TWS) earphones, 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. When it is detected that the earphone has left the user's ear, 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. Meanwhile, in order to achieve circuit protection, 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. The TVS diode is easily affected by external light, which changes its capacitance to the ground. This capacitance change will affect the detection result of the self-capacitance of the detection electrode, thereby affecting the detection performance of the proximity detection circuit.

SUMMARY OF THE INVENTION

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.

In a first aspect, a proximity detection circuit provided in a wearable device is provided, 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 to light , the self-capacitance of the detection electrode of the first detection channel; the mutual capacitance drive circuit is used to output a mutual capacitance drive signal to one of the first detection channel and the second detection channel, wherein in the mutual capacitance drive circuit Under the action of the capacitance driving signal, the mutual capacitance detection signal output by the other detection channel in the first detection channel and the second detection channel is related to the mutual capacitance change, and the mutual capacitance change is the first detection channel. 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.

When the ESD protection device in the ESD protection circuit connected to the detection channel is exposed to light, its capacitance will also change, so that the self-capacitance detection result of the detection electrode on the detection channel is affected. In this embodiment, 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.

In a possible implementation manner, the mutual capacitance detection signal is used to determine whether the self-capacitance detection signal is valid.

Specifically, 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.

In a possible implementation manner, 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. When 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.

In a possible implementation manner, 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.

Specifically, 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.

In a possible implementation manner, 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. At this time, if 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.

In a possible implementation manner, 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. The corresponding change in mutual capacitance between the detection electrodes of the two detection channels.

In this embodiment, 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.

In a possible implementation manner, the ESD protection circuit is connected to the second detection channel, or the ESD protection circuit is not connected to the second detection channel.

In one possible implementation, the ESD protection circuit includes a transient voltage suppression TVS diode.

In a possible implementation manner, 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.

In a possible implementation manner, 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.

In a possible implementation manner, 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.

In a second aspect, a wearable device is provided, including the proximity detection circuit in the first aspect or any possible implementation manner of the first aspect.

In a third aspect, a proximity detection method is provided, 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 drive signal, all The mutual capacitance detection signal output by the other detection channel in the first detection channel and the second detection channel, the mutual capacitance detection signal is related to the mutual capacitance variation, and the mutual capacitance variation is the first detection The mutual capacitance variation of the mutual capacitance between the detection electrode of the 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 detection of the first detection channel When the electrode and the detection electrode of the second detection channel, the mutual capacitance between the detection electrode of the first detection channel and the detection electrode of the second detection channel; according to the self-capacitance detection signal and the mutual capacitance The detection signal determines whether the user is approaching the detection result of the wearable device.

In a possible implementation manner, 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.

In a possible implementation manner, 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.

In a possible implementation manner, the method further includes: reacquiring the self-capacitance detection signal when the self-capacitance detection signal is determined to be invalid.

In a possible implementation manner, when the self-capacitance detection signal is determined to be valid, 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.

In a possible implementation manner, 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.

Description of drawings

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.

Detailed ways

The technical solutions in the present application will be described below with reference to the accompanying drawings.

In wearable devices, such as Bluetooth headsets and smart watches, proximity detection circuits are usually used to detect the user's touch or approach to the wearable device. For example, 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. In order to improve the reliability of capacitance detection, 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. In the following description, 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. Usually, 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. For example, when the capacitance change amount of the self-capacitance reaches a preset threshold, it will be considered that the earphone is worn on the user's ear, and then the earphone starts to play music. The threshold may be a threshold for indicating the amount of capacitance change when the user approaches the wearable device.

There is also a capacitance between the TVS diode connected to the detection channel and the ground, which is also called the junction capacitance of the TVS diode. However, 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 above problem will be described below with reference to FIG. 2 . As shown in FIG. 2 , 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. 2 , 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 , and the self-capacitance of the detection electrode S ₁ on the detection channel C ₁ to the ground is C _S1 . When the user approaches the detection electrode S ₀ , 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 ΔC S0 _body . The self-capacitance change amount ΔC _S0body is valid data expected to be detected by the proximity detection circuit 200 . However, when exposed to light, 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 ΔC _j0 . In this way, the capacitance change reflected by the detection signal output on the detection channel C ₀ includes ΔC _S0body and ΔC _j0 . The proximity detection circuit 200 will mistakenly think that the capacitance changes of the two parts ΔC _S0body and ΔC _j0 are valid data, so as to determine the detection result of the detection channel C ₀ according to the ΔC _{S0 body} and ΔC _j0 , that is, whether the user is approaching the detection electrode S ₀ detection result.

Similarly, when the user approaches the position corresponding to the detection electrode S1, the size _of the self _- capacitance C _S1 of the detection electrode S1 will change, and the capacitance change of the self-capacitance C _S1 is ΔC _S1body . The self-capacitance change amount ΔC _S1body is valid data expected to be detected by the proximity detection circuit 200 . However, when exposed to light, 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 ΔC _j1 . In this way, the capacitance variation reflected by the detection signal output from the detection channel _C1 includes ΔC _S1body and ΔC _j1 . The proximity detection circuit 200 will mistakenly think that the capacitance changes of ΔC _S1body and ΔC _j1 are valid data, so as to determine the detection result of the detection channel C ₁ according to the ΔC _{S1 body} and ΔC _j1 , that is, whether the user is approaching the detection electrode S ₁ test results.

Because of this, in practical applications, on the one hand, when the wearable device is exposed to a certain amount of light, even if there is no event that the user approaches the wearable device, 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.

Taking the earphone as an example, it is assumed that when the self-capacitance change ΔC _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 ΔC _{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. When there is light, if the user does not wear the headset, but the capacitance change ΔC _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. When there is light, if the user takes off the earphone, but the capacitance change ΔC _j0 of the TVS diode D ₀ is greater than the threshold A due to the light, then the earphone does not think that the user has taken off the earphone, but continues to play, unable to Exit normally.

It can be seen that the change of the capacitance of the TVS diode as an ESD protection circuit (or other ESD protection devices that can be affected by light to affect the capacitance) due to light will affect the result of capacitance detection, thereby affecting the detection performance of the proximity detection circuit. One solution to this is to select a suitable ESD protection diode whose junction capacitance is substantially unaffected by light, however, this leads to the difficulty and high cost of selecting an ESD protection device.

To this end, 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.

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.

Under the action of the mutual capacitance drive signal, 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.

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.

When the ESD protection device in the ESD protection circuit connected on the detection channel is illuminated, the junction capacitance of the ESD protection device will also change, which will affect the self-capacitance detection result of the detection electrode on the detection channel. In the embodiment of the present application, 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.

Generally, self-capacitance detection of proximity detection circuits in wearable devices can accommodate longer detection distances than mutual-capacitance detection. Taking the earphone as an example, due to the different size of the space in the human ear, after wearing the earphone, 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). For 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.

However, when the ESD protection device in the ESD protection circuit connected on the detection channel is illuminated, its capacitance will also change, which will affect the self-capacitance detection result of the detection electrode on the detection channel. Therefore, in this embodiment of the present application, 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. Preferably, a TVS diode can be used as the ESD protection device in the ESD protection circuit. In the following, the description will be given by taking the TVS diode as an ESD protection device as an example. At this time, 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.

Not all detection channels need to be connected to ESD protection circuits. To save cost and space, 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. In specific implementation, for example, 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.

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.

Wherein, 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.

When a user approaches the first detection channel or the TVS diode is illuminated, on the basis of the self-capacitance basic capacitance, 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.

Wherein, 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.

When a user approaches the first detection electrode, the second detection electrode, or the TVS diode is illuminated, 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.

For example, the mutual capacitance detection signal can be used to determine whether the self capacitance detection signal is valid. Optionally, 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 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. For TWS, the first threshold may be, for example, several tens of fF to several hundreds of fF.

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.

Further, optionally, 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.

That is, if the self-capacitance detection signal is considered to be valid, 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.

Optionally, 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.

FIG. 2 is a schematic diagram based on a possible implementation of the proximity detection circuit 200 shown in FIG. 1 . As shown in FIG. 2 , 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. 2 , 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 . Referring to Table 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 , and 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 , and 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.

When there is no illumination and no user approaches the positions corresponding to the first detection channel and the second detection channel, C _S0 , C _S1 , C _m , C _j0 , and C _j1 are respectively C _S0 =C _S0base , C _S1 =C _S1base , C _m =C _mbase , C _j0 =C _j0base , C _j1 =C _j1base . When a user approaches the positions corresponding to the first detection channel and the second detection channel, C _S0 , C _S1 , and C _m are respectively C _S0 =C _S0base +ΔC _S0body , C _S1 =C _S1base +ΔC _S1body , C _m =C _mbase +ΔC _mbody , that is, the amount of change is ΔC _S0body , ΔC _S1body and ΔC _mbody , respectively. When exposed to light, C _j0 and C _j1 are respectively C _j0 =C _j0base +ΔC _j0 , C _j1 =C _j1base +ΔC _j1 , that is, the change amounts are respectively ΔC _j0 and ΔC _j1 . It can be seen from Table 1 that the valid data expected to be detected by the proximity detection circuit 200 are ΔC _S0body , ΔC _S1body and ΔC _mbody , but the actually detected signals are affected by C _j0 and ΔC _j1 . △C _j0 and △C _j1 only affect the results of self-capacitance detection, but have no effect on the results of mutual capacitance detection.

Table I

When the proximity detection circuit 200 shown in FIG. 2 performs proximity detection, 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 ΔC S0 body of the detection electrode C _S0 and the capacitance change _{ΔC 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 ΔC _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.

Taking the earphone as an example, it is assumed that when the self-capacitance change ΔC _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 ΔC _{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.

When there is light, if the user does not wear the earphone, but the amount of capacitance change ΔC _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 ΔC _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.

When there is light, if the user takes off the headphones, but the amount of capacitance change ΔC _j0 of the TVS diode D ₀ is greater than the threshold A due to the light, then the user will not think that the user has taken off the headphones, so the playback continues and cannot be exited. At this time, if the mutual capacitance detection signal used to represent the mutual capacitance change ΔC _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 It will judge that the above detection result is valid, and then continue to play.

In this embodiment of the present application, 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.

For example, 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, and the third time period is used to obtain the detection electrode and the first detection channel. The corresponding change in mutual capacitance between the detection electrodes of the second detection channel. After one detection is completed, 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.

When detecting several detection channels, it can be either serial detection or parallel detection. In order to improve operability, preferably, 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.

Optionally, as shown in FIG. 2 , 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 .

Further, 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.

Further, 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.

The DAQ 250 is used to acquire self-capacitance detection signals and mutual capacitance detection signals. For example, 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 .

For example, 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 .

For another example, 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 .

For another example, 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, and 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 . For the specific description thereof, reference may be made to the description of the AFE circuit in the related art, which will not be repeated here.

In addition, 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:

310. 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;

320: Acquire 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 The self-capacitance change of the basic capacitance and the capacitance change caused by the ESD protection circuit being exposed to light, 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;

330. Output a mutual capacitance drive signal to one of the first detection channel and the second detection channel;

340. Acquire a mutual capacitance detection signal output by another detection channel in the first detection channel and the second detection channel under the action of the mutual capacitance drive signal, where the mutual capacitance detection signal is associated with the mutual capacitance Variation, 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, and 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;

350. Determine, according to the self-capacitance detection signal and the mutual capacitance detection signal, a detection result of whether the user is approaching the wearable device.

Optionally, in one embodiment, it may be determined whether the self-capacitance detection signal is valid according to the mutual capacitance detection signal; when the self-capacitance detection signal is determined to be valid, the Test results.

Optionally, in an embodiment, 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.

Optionally, in one embodiment, when the self-capacitance detection signal is determined to be invalid, the self-capacitance detection signal is re-acquired.

Optionally, in an embodiment, when the self-capacitance detection signal is determined to be valid, 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.

Optionally, in one embodiment, 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. For the corresponding self-capacitance variation, 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.

Preferably, 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.

It should be understood that 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.

As an example and not a limitation, 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.

It should be noted that, on the premise of no conflict, each embodiment described in this application and/or the technical features in each embodiment can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the protection scope of this application .

It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art to better understand the embodiments of the present application, rather than limiting the scope of the embodiments of the present application, and those skilled in the art can Various improvements and modifications can be made, and these improvements or modifications all fall within the protection scope of the present application.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

A proximity detection circuit, characterized in that it is 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 connected to There is an electrostatic discharge ESD protection circuit, and the proximity detection circuit includes:

A self-capacitance drive circuit is used to input a self-capacitance drive signal to a first detection channel to be detected among the plurality of detection channels, the first detection channel is connected with the ESD protection circuit, and the first detection channel is in The self-capacitance detection signal output under the action of the self-capacitance drive signal, the self-capacitance change of the self-capacitance of the detection electrode associated with the first detection channel relative to the self-capacitance basic capacitance, and the ESD protection circuit exposed to light. The amount of capacitance change caused, 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;

A mutual capacitance drive circuit is used to output a mutual capacitance drive signal to one of the first detection channel and the second detection channel, wherein, under the action of the mutual capacitance drive signal, the first detection channel and the The mutual capacitance detection signal output by another detection channel in the second detection channel is related to the mutual capacitance variation, and the mutual capacitance variation is the difference between 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 basic capacitance, where the mutual capacitance basic capacitance includes: when no user approaches the detection electrodes of the first detection channel and the detection electrodes of the second detection channel , the mutual capacitance between the detection electrodes of the first detection channel and the detection electrodes of the second detection channel; and

The signal processing circuit 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 according to claim 1, wherein the mutual capacitance detection signal is used to determine whether the self capacitance detection signal is valid.
The proximity detection circuit according to claim 2, wherein:

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 less than the first threshold, the self-capacitance detection signal is determined to be invalid;

Wherein, the first threshold is used to indicate the threshold of the mutual capacitance detection signal when the user approaches the wearable device.
The proximity detection circuit according to claim 2 or 3, characterized in that:

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 proximity detection circuit according to claim 4, wherein the signal processing circuit is used for:

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 proximity detection circuit according to any one of claims 1 to 5, wherein one 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 the self-capacitance change amount corresponding to the first detection channel, 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 self-capacitance change amount. The amount of change in mutual capacitance corresponding to the detection electrode of the first detection channel and the detection electrode of the second detection channel.
The proximity detection circuit according to any one of claims 1 to 6, wherein the ESD protection circuit comprises a transient voltage suppression TVS diode.
The proximity detection circuit according to any one of claims 1 to 7, wherein the proximity detection circuit further comprises:

a multiplexer, connected to the plurality of detection channels, the self-capacitance driving circuit and the mutual capacitance driving circuit, and used for electrically connecting the detection channel to be detected among the plurality of detection channels to the self-capacitance A drive circuit or the mutual capacitance drive circuit.
The proximity detection circuit according to claim 8, wherein the signal processing circuit comprises:

a data acquisition circuit DAQ for acquiring the self-capacitance detection signal and the mutual capacitance detection signal; and,

A digital signal processing circuit DSP, connected to the DAQ, is configured to determine the detection result according to the self-capacitance detection signal and the mutual capacitance detection signal.
The proximity detection circuit according to any one of claims 1 to 9, wherein the wearable device comprises a true wireless stereo TWS headset, a smart watch or smart glasses.
A wearable device, comprising the proximity detection circuit according to any one of claims 1 to 10.
A method for proximity detection, comprising:

inputting a self-capacitance drive signal to a first detection channel to be detected in the 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;

outputting a mutual capacitance drive signal to one of the first detection channel and the second detection channel;

Acquire a mutual capacitance detection signal output by another detection channel in the first detection channel and the second detection channel under the action of the mutual capacitance drive signal, where the mutual capacitance detection signal is associated with a change in the mutual capacitance , the mutual capacitance variation is the mutual capacitance variation of the mutual capacitance between the detection electrode of the first detection channel and the detection electrode of the second detection channel relative to the mutual capacitance basic capacitance, the mutual capacitance basic capacitance Including: when no user approaches the detection electrodes of the first detection channel and the detection electrodes of the second detection channel, the mutual capacitance between the detection electrodes of the first detection channel and the detection electrodes of the second detection channel ;

The detection result of whether the user is approaching the wearable device is determined according to the self-capacitance detection signal and the mutual capacitance detection signal.
The method according to claim 12, wherein the detecting result of determining whether a user is close to the wearable device according to the self-capacitance detection signal and the mutual-capacity detection signal comprises:

Determine whether the self-capacitance detection signal is valid according to the mutual capacitance detection signal;

When the self-capacitance detection signal is determined to be valid, the detection result is determined according to the self-capacitance detection signal.
The method according to claim 13, wherein the determining whether the self-capacitance detection signal is valid according to the mutual capacitance detection signal comprises:

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 first threshold, determine that the self capacitance detection signal is invalid;

The first threshold is used to indicate the threshold of the mutual capacitance detection signal when the user approaches the wearable device.
The method according to claim 13 or 14, wherein the method further comprises:

When the self-capacitance detection signal is determined to be invalid, the self-capacitance detection signal is acquired again.
The method according to claim 13 or 14, wherein when the self-capacitance detection signal is determined to be valid, determining the detection result according to the self-capacitance detection signal, comprising:

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 method according to any one of claims 12 to 16, wherein the self-capacitance variation corresponding to the first detection channel is acquired in a first period of a detection period, and in the first period of the detection period The self-capacitance variation corresponding to the second detection channel is acquired in two periods, and the correspondence 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 cycle of the mutual capacitance change.