WO2020062077A1

WO2020062077A1 - Circuit and electronic device

Info

Publication number: WO2020062077A1
Application number: PCT/CN2018/108447
Authority: WO
Inventors: 程树青
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2020-04-02
Also published as: CN109496395A

Abstract

A circuit and an electronic device. The circuit comprises: an antenna (11), a touch-control chip (12) and a communication chip (13), wherein the antenna (11) forms a detection electrode, and the detection electrode is electrically connected to the touch-control chip (12) and the communication chip (13), respectively; and when a finger touches the antenna (11), the capacitance of the antenna (11) changes, the touch-control chip (12) detects a change in transmission data of the detection electrode, and the touch-control chip (12) triggers the electronic device to execute an instruction corresponding to a touch-control operation. Compared with the prior art, the circuit and the electronic device can realize two functions, the functions of an antenna and touch control, by means of the antenna (11), so that the functions of touch control and an antenna are effectively integrated, the circuit occupies a smaller volume, and a touch-control operation is more sensitive.

Description

Circuit and electronic equipment

Technical field

The embodiments of the present application relate to the field of touch control, and in particular, to a circuit and an electronic device.

Background technique

In recent years, with the continuous development of communication technology and the continuous advancement of science and technology, electronic devices such as headphones, watches, and bracelets have become essential tools for people's daily life. In particular, electronic devices such as Bluetooth headsets, Bluetooth watches, and Bluetooth bracelets with Bluetooth antennas have brought great convenience to people's lives. At present, electronic devices such as Bluetooth headsets, Bluetooth watches, and Bluetooth bracelets are small and convenient to communicate with other devices using wireless connection methods, making them more and more widely used.

However, at least the following problems exist in the prior art: there is a contradiction between miniaturization and diversified functions. For example, a Bluetooth headset needs functions such as volume control and song switching. A single button cannot solve the problem, but multiple buttons require more space. The electronic device becomes larger. The diversification of functions also requires a larger battery to support, it will also occupy a larger space, and will also cause the electronic device to become larger. And in the case of limited space, if the space occupied by the antenna is large, the touch area will be reduced and the detection will be insensitive.

Summary of the Invention

The purpose of the embodiments of the present application is to provide a circuit and an electronic device. The antenna is a detection electrode, so that when a user's finger touches the antenna, a change in the capacitance of the antenna can be detected by the touch chip, which triggers the electronic device to perform a touch operation. Corresponding instruction. Therefore, the two functions of the antenna and the touch are realized through the antenna, the functions of the touch and the antenna are effectively integrated, and the circuit designed in this application occupies a small volume, and the touch operation is more sensitive.

In order to solve the above technical problem, an embodiment of the present application provides a circuit, which is applied to an electronic device. The circuit includes: an antenna, a touch chip, and a communication chip; the antenna is a detection electrode, and the detection electrode The touch chip and the communication chip are respectively electrically connected; when a finger touches the antenna, the capacitance of the antenna changes, the touch chip detects the change in the capacitance and triggers the The electronic device executes a command corresponding to a touch operation.

An embodiment of the present application further provides an electronic device including at least one touch key and the above circuit; one of the touch keys is formed by the antenna.

In the embodiment of the present application, compared with the prior art, the antenna is formed by a detection electrode, and the detection electrode is electrically connected to the touch chip and the communication chip, respectively. When a finger touches the antenna, the capacitance of the antenna changes, the touch chip detects the change in the capacitance, and the touch chip triggers the electronic device to execute a command corresponding to the touch operation. In other words, when the user's finger touches the antenna, the capacitance of the antenna changes. Since the antenna and the touch chip are electrically connected, the change in the capacitance of the antenna can be detected by the touch chip, and the touch chip can trigger the execution of the electronic device. Commands corresponding to touch operations. Therefore, the antenna and touch functions can be implemented through the antenna at the same time, that is, the antenna can realize the communication function and also the function of the touch key, effectively integrate the touch and the function of the antenna, and the circuit designed in this application The occupied volume is small and the touch operation is more sensitive.

In addition, the length of the antenna is a quarter of the wavelength of the signal in the working frequency band of the antenna. Designing the length of the antenna to a quarter of the working wavelength of the antenna can make the antenna have better radiation ability.

In addition, the circuit further includes a high-pass filter circuit; the high-pass filter circuit is electrically connected between the detection electrode and the communication chip. Through this circuit design, low-frequency signals during touch operation can be filtered out, and at the same time, a large measurement error caused by the change in the impedance of the radio frequency circuit including the antenna can be avoided.

In addition, the high-pass filter circuit includes a third capacitor, a fourth capacitor, and a first inductor; the third capacitor and the fourth capacitor are connected in series between the detection electrode and the communication chip, and the first inductor One end is connected between the third capacitor and the fourth capacitor, and the other end of the first inductor is connected to the system ground. Through this circuit design, a specific circuit form of a high-pass filter circuit is provided. In actual design, the high-pass filter circuit can be designed as a lumped parameter circuit or the high-pass filter circuit can be designed as a microstrip filter circuit.

In addition, the circuit further includes a low-pass filter circuit; the low-pass filter circuit is electrically connected between the detection electrode and the touch chip. Through this circuit design, it is possible to reduce the interference of the touch operation when the antenna emits high-frequency signals, and at the same time avoid the parasitic effect of the touch circuit composed of the detection electrode and the touch chip from affecting the receiving performance of the antenna.

In addition, the low-pass filter circuit includes a second inductor, a third inductor, and a fifth capacitor; the second inductor and the third inductor are connected in series between the detection electrode and the touch chip, and the first One end of the five capacitors is connected between the second inductor and the third inductor, and the other end of the fifth capacitor is connected to the system ground. Through this circuit design, a specific circuit form of the low-pass filter circuit is provided, and in the actual design, the low-pass filter circuit can be designed as a lumped parameter circuit or the high-pass filter circuit can be designed as a microstrip filter circuit. .

In addition, the circuit also includes a battery and an isolation circuit for isolating the battery from the system ground, and the isolation circuit is a lumped parameter circuit or a microstrip filter circuit. Because the isolation circuit isolates the battery's negative electrode from the system ground, the battery will not have a shielding effect on the antenna's radiation, so the distance between the battery and the antenna can be set closer, reducing the size of the electronic device.

In addition, the isolation circuit is a lumped parameter circuit including a common mode choke; the common mode choke includes a first common mode inductor and a second common mode inductor; and one end of the first common mode inductor is connected The other end of the battery negative terminal is connected to the system ground; one end of the second common mode inductor is connected to the positive terminal of the battery, and the other end is connected to a preset voltage. Since the high-frequency signal radiated by the antenna can be isolated from the system ground by the common mode choke coil, and will not be absorbed by the system, the radiation performance of the antenna can be improved by the common mode choke coil.

In addition, the isolation circuit is a lumped parameter circuit, including: a first separation inductor, a second separation inductor, and a separation capacitor; the first separation inductor, the separation capacitor, and the separation second inductor are connected in series in the order Between a positive electrode and a negative electrode of the battery, a connection terminal of the first separation inductor and the separation capacitor is used to connect a preset voltage, and a connection terminal of the second separation inductor and the separation capacitor is connected to a system ground. This circuit design can prevent the battery from affecting the radiation performance of the antenna.

In addition, the isolation circuit is a microstrip filter circuit, including: a first microstrip line, a second microstrip line, and a seventh capacitor; the first microstrip line, the seventh capacitor, and the second microstrip The strip line is connected in series between the positive electrode and the negative electrode of the battery, the connection between the first microstrip line and the seventh capacitor is connected to a preset voltage, and the second microstrip line and the seventh capacitor Connect the termination system ground. This circuit design can provide another specific form of isolation circuit, which helps to match the different design requirements of the user's design process.

In addition, the touch key includes a first touch key, a second touch key, and a third touch key; the third touch key is formed by the antenna and is located between the first touch key and the third touch key Between the second touch keys. With this design, the functions of the electronic device can be diversified without occupying a large space, which can contribute to the miniaturization design of the electronic device.

In addition, the third touch key is located between the first touch key and the second touch key, and the first touch key, the second touch key, and the third touch key The outer contour shape formed by the key combination is circular. With this design, the space occupied by the antenna is relatively concentrated. When the shape of the electronic device is circular, it helps to match the shape of the electronic device, and the design takes up less space.

In addition, the first touch key, the second touch key, and the third touch key are arranged in order, the first touch key and the second touch key are rectangular, and the third The touch keys are serpentine. With this design, when the shape of the electronic device is rectangular, the shape of the electronic device can be matched.

In addition, the electronic device is an earphone, a watch, or a bracelet, so that the universality of the present application can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments are exemplarily described by using pictures in corresponding drawings, and these exemplary descriptions do not limit the embodiments.

FIG. 1 is a structural block diagram of a circuit according to a first embodiment of the present application;

2 is a schematic structural diagram of an antenna according to a first embodiment of the present application;

3 is a structural diagram of a circuit according to a second embodiment of the present application;

4 is a structural diagram of an auxiliary function module circuit according to a third embodiment of the present application;

5 is a structural diagram of an isolation circuit according to a third embodiment of the present application;

6 is another structural diagram of an isolation circuit according to a third embodiment of the present application;

7 is a schematic diagram of a circuit structure of an electronic device according to a fifth embodiment of the present application;

FIG. 8 is a diagram illustrating an electronic device according to a fifth embodiment of the present application.

detailed description

In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, a person of ordinary skill in the art can understand that in the embodiments of the present application, many technical details are provided in order to make the reader better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in this application can be implemented.

A first embodiment of the present application relates to a circuit applied to an electronic device. As shown in FIG. 1, the circuit includes: an antenna 11, a touch chip 12, and a communication chip 13. The antenna 11 is a detection electrode, and the detection electrode is electrically connected to the touch chip 12 and the communication chip 13 respectively. When a finger touches the detection electrode, the capacitance of the detection electrode changes, and the touch chip 12 detects the change in the capacitance, and triggers the electronic device to execute an instruction corresponding to a touch operation.

The antenna 11 of the present application is formed of a detection electrode, and the detection electrodes are electrically connected to the touch chip 12 and the communication chip 13, respectively. When a finger touches the detection electrode, the capacitance of the detection electrode changes, and the touch chip 12 detects the change in the capacitance, and triggers the electronic device to execute an instruction corresponding to the touch operation. That is, when the user's finger touches the antenna 11, the capacitance of the antenna 11 changes. Since the antenna 11 and the touch chip 12 are electrically connected, the change in the capacitance of the antenna 11 can be detected by the touch chip 12 The chip 12 may trigger an electronic device to execute an instruction corresponding to a touch operation. It is worth noting that the antenna 11 in the embodiment of the present application can perform a communication function and a touch function at the same time. The antenna 11 and the touch function are simultaneously implemented by the antenna 11, and the functions of the touch and the antenna 11 are effectively integrated, and the circuit designed in this application occupies a small volume, and the touch operation is more sensitive.

In practical applications, the touch chip 12 is provided with an integration circuit 14 and a processing unit 121 for detecting the capacitance of the detection electrode. The detection electrode is electrically connected to an input terminal of the integration circuit 14, and an output terminal of the integration circuit 14 is electrically connected to the processing unit 121. When a finger touches the detection electrode, the capacitance of the detection electrode changes, the processing unit 121 detects a change in the voltage at the output terminal of the integration circuit 14, and triggers the electronic device to execute an instruction corresponding to a touch operation. Therefore, the touch function is implemented, and a specific implementation form for detecting a finger touch is provided, which is helpful to improve the feasibility of the present application.

For example, before a finger touches the detection electrode, a parasitic capacitance C _KG is formed between the detection electrode and the system ground, that is, a parasitic capacitance C _KG is formed between the antenna 11 and the system ground. At this time, the capacitance of the detection electrode was C _KG . After the finger touches the detection electrode, a first capacitance C _FK is formed between the finger and the detection electrode, that is, a first capacitance C _FK is formed between the finger and the antenna 11, and a second capacitance C _FG is formed between the finger and the system ground. At this time, the capacitance of the detection electrode is the total capacitance of C _KG , C _FK and C _FG . Because C _FK and C _{FG are} connected in series with C _{KG in} parallel. Therefore, the amount of change in capacitance ΔC is the total capacitance of C _FK and C _FG .

ΔC = C _FK * C _FG / (C _FK + C _FG ).

The amount of change in the amount of electricity is ΔQ = ΔC * U _K. Among them, U _K is a preset coding voltage injected by the circuit system 10 to the detection electrode.

When the power is changed, the voltage at the output terminal of the integrating circuit 14 changes. At this time, the processing unit 121 can recognize that the voltage at the output terminal of the integrating circuit 14 changes, so that it can be determined that a finger touches the antenna 11.

As shown in FIG. 2, the length of the antenna 11 is a quarter of the signal wavelength of the operating frequency band of the antenna 11. Designing the length of the antenna 11 to a quarter of the wavelength of the signal in the working frequency band of the antenna 11 can make the antenna 11 have better radiation capability. The antenna 11 of this embodiment may be designed as a snake-shaped structure. It is worth mentioning that the antenna 11 is not limited to a serpentine structure. Any shape that can ensure that the length of the antenna 11 is a quarter of the wavelength of the signal in the working frequency band of the antenna 11 is within the protection scope of the present application. Taking the antenna 11 as a Bluetooth antenna as an example for description, the Bluetooth frequency band is 2.4 GHz, and the length of the antenna 11 is designed to be a quarter of the signal wavelength in the frequency band, which has good radiation ability. However, the antenna 11 of the present application is not limited to a Bluetooth antenna. For example, the antenna 11 can be designed as a Zigbee antenna (Zigbee is a low-power local area network protocol based on the IEEE802.15.4 standard) or a WiFi antenna (WiFi is an Electronic devices are connected to a wireless local area network (LAN) technology, etc., and no further examples are given here.

In addition, the circuit further includes a high-pass filter circuit 15. The high-pass filter circuit 15 is electrically connected between the antenna 11 and the communication chip 13. , The low frequency signals can be filtered by this circuit design (for example, the filtered U _K), while avoiding large impedance changes due to the radio frequency circuit (including an antenna member 11, etc.) caused by the change of the detection of the capacity of Measurement error. It is worth pointing out that the specific form of the high-pass filter circuit 15 may be a lumped parameter circuit or a microstrip filter circuit.

The circuit also includes a low-pass filter circuit 16. The low-pass filter circuit 16 is electrically connected between the detection electrode and the touch chip 12. This circuit design can reduce the interference of high-frequency signals on touch detection. The high-frequency signals here are the high-frequency signals injected by the Bluetooth signal during transmission, and the parasitic effects of the touch circuit can be avoided to affect the reception performance of the antenna 11. , Can make the antenna 11 work independently. It is worth pointing out that the specific form of the low-pass filter circuit 16 may be a lumped parameter circuit or a microstrip filter circuit.

When the circuit includes both the high-pass filter circuit 15 and the low-pass filter circuit 16 described above, the branch performing the communication function and the branch performing the touch function will not affect each other. Therefore, the antenna 11 can perform communication and touch simultaneously. Two functions.

Compared with the prior art, this embodiment makes it possible to detect a change in the capacitance of the antenna 11 through the touch chip 12 when the user touches the antenna 11 with a finger, and trigger the electronic device to execute an instruction corresponding to the touch operation. Therefore, the two functions of the antenna 11 and the touch can be realized by the antenna 11 at the same time, and the functions of the touch and the antenna 11 are effectively integrated, and the circuit designed by the present application occupies a small volume and the touch operation is more sensitive.

A second embodiment of the present application relates to a circuit applied to an electronic device. This embodiment is further improved based on the first embodiment. The main improvement lies in that this embodiment provides specific forms of a high-pass filter circuit, a low-pass filter circuit, and an integration circuit.

As shown in FIG. 3, the circuit further includes a high-pass filter circuit 15. The high-pass filter circuit 15 is electrically connected between the detection electrode and the communication chip 13. Through this circuit design, low-frequency signals can be filtered (such as U _K is filtered), and at the same time, a large measurement error is not caused when the above-mentioned detection capacitance changes due to the impedance change of the radio frequency circuit. Specifically, the high-pass filter circuit includes two capacitors and one inductor, respectively: a third capacitor C1, a fourth capacitor C2, and a first inductor L1. Two capacitors are connected in series between the detection electrode and the communication chip 13, one end of the first inductor L1 is connected between the two capacitors, and the other end is connected to the system ground. That is, the third capacitor C1 and the fourth capacitor C2 are connected in series between the detection electrode and the communication chip 13, one end of the first inductor L1 is connected to a connection terminal between the two capacitors, and the other end of the first inductor L1 Connect to system ground. Through this circuit design, a specific circuit form of a high-pass filter circuit is provided. In actual design, the high-pass filter circuit can be designed as a lumped parameter circuit or the high-pass filter circuit can be designed as a microstrip filter circuit.

The circuit also includes a low-pass filter circuit 16. The low-pass filter circuit 16 is electrically connected between the detection electrode and the touch chip 12. This circuit design can reduce the interference of high-frequency signals on touch detection. The high-frequency signals here are the high-frequency signals injected by the Bluetooth signal during transmission, and the parasitic effects of the touch circuit can be avoided to affect the reception performance of the antenna 11. , Can make the antenna 11 work independently. It is worth pointing out that the specific form of the low-pass filter circuit 16 may be a lumped parameter circuit or a microstrip filter circuit. Specifically, the low-pass filter circuit includes two inductors and one capacitor, respectively: a second inductor L2, a third inductor L3, and a fifth capacitor C3. Two inductors are connected in series between the detection electrode and the touch chip 12, one end of the fifth capacitor C3 is connected between the two inductors, and the other end is connected to the system ground. That is, the second inductor L2 and the third inductor L3 are connected in series between the detection electrode and the touch chip 12, one end of the fifth capacitor C3 is connected to a connection terminal between the two inductors, and the fifth capacitor C3 The other end is connected to the system ground. Through this circuit design, a specific circuit form of a low-pass filter circuit is provided, and in the actual design, the low-pass filter circuit can be designed as a lumped parameter circuit or the high-pass filter circuit can be designed as a microstrip filter circuit. . In addition, it should be noted that the capacitance of the fifth capacitor C3 cannot be too large. If the capacitance of the fifth capacitor C3 is too large to exceed the load capacity of the touch chip 12, the touch chip 12 cannot implement the touch function.

Compared with the prior art, this embodiment includes both the above-mentioned high-pass filter circuit 15 and low-pass filter circuit 16. The high-pass filter circuit 15 can filter out low-frequency signals while avoiding the above-mentioned detection capacitance due to impedance changes of the RF circuit. Changes in the measurement result in larger measurement errors. In addition, the low-pass filter circuit 16 can reduce the interference of high-frequency signals on touch detection, and at the same time can avoid the parasitic effect of the touch circuit from affecting the receiving performance of the antenna 11, and can make the antenna 11 work independently. The branch performing the communication function and the branch performing the touch function do not affect each other. Therefore, the antenna 11 can perform two functions of communication and touch simultaneously.

A third embodiment of the present application relates to a circuit applied to an electronic device. This embodiment is further improved based on the first embodiment. The main improvement is that the circuit further includes a battery and an isolation circuit for isolating the battery from the system ground. The isolation circuit may be a lumped parameter circuit or a microstrip filter circuit. The specific form of the isolation circuit is briefly described below:

As shown in FIG. 4, the isolation circuit is a lumped parameter circuit and includes a common mode choke coil 18. The common mode choke coil 18 includes a first common mode inductor and a second common mode inductor. One end of the first common mode inductor is connected to a battery negative electrode, and the other end is connected to a system ground GND. One end of the second common mode inductor is connected to a battery positive electrode, and the other end is connected to a preset voltage V _BAT . Since the high-frequency signal radiated by the antenna 11 can be isolated from the system ground by the common mode choke coil and will not be absorbed by the system, the high frequency signal on the antenna can be isolated from the system by the common mode choke coil. Specifically, since the common mode rejection ratio of the common mode choke coil 18 is very large, the high frequency signal radiated by the antenna 11 will not be coupled to the system ground through the common mode choke coil 18 and the battery negative electrode, and the antenna 11 will not be radiated. The high-frequency signal is absorbed by the circuit system, but the energy of the high-frequency signal is radiated out. Therefore, the radiation performance of the antenna 11 can be improved by the common mode choke coil 18.

As shown in FIG. 5, the isolation circuit is a lumped parameter circuit, and includes: a first separation inductor L_Battery, a second separation inductor L_GND, and a separation capacitor C_filter. The first separation inductor L_Battery, the separation capacitor C_filter, and the second separation inductor L_GND are connected in series between the positive electrode and the negative electrode of the battery in sequence. Connected to the preset voltage V-Battery, and the connection between the second separation inductor L_GND and the separation capacitor C_filter is connected to the system ground. This circuit design can prevent the battery from affecting the radiation performance of the antenna.

As shown in FIG. 6, the isolation circuit is a microstrip filter circuit, and includes a first microstrip line W1, a second microstrip line W2, and a seventh capacitor C7. The first microstrip line W1, the seventh capacitor C7, and the second microstrip line W2 are connected in series between a positive electrode and a negative electrode of the battery in this order. The connection between the first microstrip line W1 and the seventh capacitor C7 is terminated with a preset voltage V _BAT , and the connection between the second microstrip line W2 and the seventh capacitor C7 is terminated with the system ground GND. Wherein, the first microstrip line W1 and the second microstrip line W2 are both snake-shaped structures and have the same length.

Specifically, when the isolation circuit is composed of a microstrip filter, the equivalent input impedance of the isolation circuit is Z _in .

Z ₀ and Z _L are the impedances of the first microstrip line W1 and the second microstrip line W2, respectively.

Signal wavelength in microstrip

When the length d of the antenna is designed to be a quarter of the signal wavelength in the working frequency band, that is, d = λ / 4, tan (βd) = ∞. The formula of equivalent input impedance at this time is simplified as:

Because C _{KG is} very large, the impedance in the RF circuit is equivalent to Z _L = 0, so Zin = ∞, so the battery can be isolated from the system ground through the above circuit design.

Compared with the prior art, because the isolation circuit isolates the negative electrode of the battery from the system ground in this embodiment, the battery does not have a shielding effect on the radiation of the antenna, so that the distance between the battery and the antenna can be set closer. Reduce the size of electronic equipment.

A fourth embodiment of the present application relates to an electronic device. The electronic device includes at least one touch key and the circuit of the first, second or third embodiment, and one of the touch keys is formed by the antenna.

It is worth mentioning that the electronic device in this embodiment may be, but is not limited to, an earphone, a watch, or a bracelet, so that the universality of the present application can be improved. If the antenna in the circuit is a Bluetooth antenna, the headset can be a Bluetooth headset, the watch can be a Bluetooth watch, and the bracelet can be a Bluetooth bracelet.

Compared with the prior art, the electronic device of this embodiment can simultaneously implement two functions of an antenna and a touch control through an antenna.

It is not difficult to find that this embodiment is an example of a device corresponding to the first, second or third embodiment, and this embodiment can be implemented in cooperation with the first, second or third embodiment. The related technical details mentioned in the first, second or third embodiments are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Correspondingly, the relevant technical details mentioned in this embodiment can also be applied in the first, second or third embodiment.

A fifth embodiment of the present application relates to an electronic device. This embodiment is further improved on the basis of the fourth embodiment. The main improvement is that this embodiment includes other touch keys in addition to the touch keys formed by the antenna according to the fourth embodiment. .

As shown in FIG. 7, the touch keys of the electronic device include a first touch key 62, a second touch key 63, and a third touch key 61, and the third touch key 61 is formed by the antenna. With this design, the functions of the electronic device can be diversified without occupying a large space, which can contribute to the miniaturization design of the electronic device. The third touch key 61 is located between the first touch key 62 and the second touch key 63. The first touch key 62, the second touch key 63, and the first The outer contour formed by combining the three touch keys 61 is circular. With this design, the space occupied by the antenna is relatively concentrated. When the shape of the electronic device is circular, it helps to match the shape of the electronic device, and the design takes up less space. As shown in FIG. 8, the first touch key 62, the second touch key 63, and the third touch key 61 are sequentially arranged, and the first touch key 62 and the second touch key The key 63 is rectangular, and the third touch key 61 is serpentine. When the shape of the electronic device is rectangular, it helps to match the shape of the electronic device.

Compared with the prior art, this embodiment can make the space occupied by the antenna more concentrated, and can adapt to electronic devices of different shapes.

Those of ordinary skill in the art can understand that the foregoing implementation manners are specific embodiments for implementing the present application, and in practical applications, various changes can be made in form and details without departing from the spirit and range.

Claims

A circuit is characterized in that the circuit is applied to an electronic device, and the circuit includes:

Antenna, touch chip and communication chip;

The antenna is a detection electrode, and the detection electrode is electrically connected to the touch chip and the communication chip, respectively;

When a finger touches the detection electrode, the capacitance of the detection electrode changes, and the touch chip detects the change in the capacitance, and triggers the electronic device to execute an instruction corresponding to a touch operation.
The circuit according to claim 1, wherein a length of the antenna is a quarter of a signal wavelength of a working frequency band of the antenna.
The circuit of claim 1, further comprising a high-pass filter circuit;

The high-pass filter circuit is electrically connected between the detection electrode and the communication chip.
The circuit according to claim 3, wherein the high-pass filter circuit includes a third capacitor, a fourth capacitor, and a first inductor;

The third capacitor and the fourth capacitor are connected in series between the detection electrode and the communication chip, and one end of the first inductor is connected between the third capacitor and the fourth capacitor. The other end of the first inductor is connected to the system ground.
The circuit according to claim 1, further comprising a low-pass filter circuit;

The low-pass filter circuit is electrically connected between the detection electrode and the touch chip.
The circuit according to claim 5, wherein the low-pass filter circuit comprises a second inductor, a third inductor, and a fifth capacitor;

The second inductor and the third inductor are connected in series between the detection electrode and the touch chip, and one end of the fifth capacitor is connected between the second inductor and the third inductor, The other end of the fifth capacitor is connected to the system ground.
The circuit according to any one of claims 1-6, further comprising a battery and an isolation circuit for isolating the battery from a system ground, wherein the isolation circuit is a lumped parameter circuit or Microstrip filter circuit.
The circuit according to claim 7, wherein the isolation circuit is a lumped parameter circuit including a common mode choke;

The common mode choke includes a first common mode inductor and a second common mode inductor;

One end of the first common mode inductor is connected to a battery negative electrode, and the other end is connected to a system ground;

One end of the second common mode inductor is connected to the positive electrode of the battery, and the other end is connected to a preset voltage.
The circuit according to claim 7, wherein the isolation circuit is a lumped parameter circuit, comprising: a first separation inductor, a second separation inductor, and a separation capacitor;

The first separation inductor, the separation capacitor, and the second separation inductor are connected in series between a positive electrode and a negative electrode of the battery in sequence, and the connection between the first separation inductor and the separation capacitor is connected to a preset voltage, The connection of the second separation inductor and the separation capacitor is terminated to a system ground.
The circuit according to claim 7, wherein the isolation circuit is a microstrip filter circuit, comprising: a first microstrip line, a second microstrip line, and a seventh capacitor;

The first microstrip line, the seventh capacitor, and the second microstrip line are connected in series between a positive electrode and a negative electrode of the battery in sequence, and the connection ends of the first microstrip line and the seventh capacitor are connected in series. At a predetermined voltage, the connection between the second microstrip line and the seventh capacitor is terminated to the system ground.
The circuit according to claim 10, wherein the first microstrip line and the second microstrip line are both serpentine structures and have the same length.
An electronic device, comprising at least one touch key and the circuit according to any one of claims 1-11;

One of the touch keys is formed by the antenna.
The electronic device according to claim 12, wherein the touch keys include a first touch key, a second touch key, and a third touch key; the third touch key is formed by the antenna .
The electronic device according to claim 13, wherein the third touch key is located between the first touch key and the second touch key, and the first touch key, the The outer contour shape formed by the combination of the second touch key and the third touch key is circular.
The electronic device according to claim 13, wherein the first touch key, the second touch key, and the third touch key are sequentially arranged, and the first touch key and the third touch key are sequentially arranged. The second touch key is rectangular, and the third touch key is serpentine.
The electronic device according to claim 12, wherein the electronic device is an earphone, a watch, or a bracelet.