WO2022155874A1

WO2022155874A1 - Detection circuit, chip, and related electronic apparatus

Info

Publication number: WO2022155874A1
Application number: PCT/CN2021/073195
Authority: WO
Inventors: 余倩
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2022-07-28

Abstract

A detection circuit (100, 200), a chip, and a related electronic apparatus, wherein the detection circuit (100, 200) comprises: a first input end (P1), a second input end (P2), an input end (NSA1) of a differential integral circuit (110, 210), an energy storage member (A1), first to sixth switching circuits (SW1-SW6), and the differential integral circuit (110, 210). The detection circuit (100, 200) generates a detection voltage signal (VOUT) according to a sensed capacitance value between the first input end (P1) and the second input end (P2). The first switching circuit (SW1) is coupled to the first input end (P1), the input end (NSA1) of the differential integral circuit (110, 210), and the ground (GND). The second switching circuit (SW2) is coupled to the second input end (P2), the input end (NSA1) of the differential integral circuit (110, 210), and the ground (GND). The third switching circuit (SW3) is coupled to the input end (NSA1) of the differential integral circuit (110, 210), and an operating voltage (VDD). The fourth switching circuit (SW4) is coupled to the energy storage member (A1) and the ground (GND). The fifth switching circuit (SW5) is coupled to the energy storage member (A1), the ground (GND) and the operating voltage (VDD). The sixth switching circuit (SW6) is coupled to a first end of the energy storage member (A1) and the input end (NSA1) of the differential integral circuit (110, 210). The differential integral circuit (110, 210) is configured to perform integration according to the voltage at the input end (NSA1) of the differential integral circuit (110, 210) so as to generate the detection voltage signal (VOUT).

Description

Detection circuits, chips and related electronic devices

technical field

The present application relates to a detection circuit, and in particular, to a self-capacitance detection circuit, a chip and related electronic devices.

Background technique

Electronic products often involve various human-computer interactions based on capacitance detection. For example, in earphones, capacitive in-ear detection is often used to realize the wearing/dropping detection of earphones to control whether the earphones perform various operations such as music playback, and capacitive touch detection is used to realize gestures such as single click, double click, and slide. recognition, and then complete human-computer interaction in various application scenarios; for example, touch detection or gesture recognition based on capacitive detection is also involved in mobile phone and vehicle touch control. However, as the temperature changes, the capacitance value of the detected capacitor also changes, and this phenomenon of capacitance change due to temperature often leads to wrong judgments in applications. For example, in the process of wearing the headset, the ambient temperature will cause the capacitance value of the self-capacitance itself to change. This change can easily be misjudged as wearing, falling off, or touching the earphones, causing misoperation.

In addition, in the prior art, since the capacitance detection value read by the reading circuit actually includes the capacitance value change caused by temperature, in order to reserve the capacitance value change range caused by temperature, the capacitance value read by the reading circuit The effective sensing range of the obtained value is quite limited, which often leads to inaccurate judgment when judging whether a human body is approaching based on the capacitance detection value or inaccurate judgment for other applications based on the capacitance detection value. For example, the signal amount of the valid sensing signal is small, which makes it difficult for the back-end circuit to accurately identify the valid sensing signal.

SUMMARY OF THE INVENTION

One of the objectives of the present application is to disclose a detection circuit, a chip and related electronic devices to solve some or all of the above problems.

An embodiment of the present application provides a detection circuit coupled to a sensing capacitor, the sensing capacitor has an inherent capacitance value, and the sensing capacitance value of the sensing capacitor changes at least due to the proximity of a human body. The detection circuit includes a first input terminal, a second input terminal, a differential integration circuit, a first switching circuit, a second switching circuit, a third switching circuit, an energy storage element, a fourth switching circuit, a fifth switching circuit and a sixth switching circuit switch circuit.

The first input terminal of the detection circuit is coupled to the first terminal of the sensing capacitor. The second input end of the detection circuit is connected to the second end of the sensing capacitor. The differential integrator circuit has an input terminal and is used for integrating according to the terminal voltage of the input terminal of the differential integrator circuit to generate a detection voltage signal when the detection circuit performs a detection operation. The first switching circuit is coupled to the first input terminal of the detection circuit, the input terminal of the differential integration circuit and the ground terminal, and the first switching circuit is used for turning on or off the detection The electrical connection between the first input terminal of the circuit and the input terminal of the differential integration circuit, and turning on or off the electrical connection between the first input terminal of the detection circuit and the ground terminal Electrical connection. The second switching circuit is coupled to the second input terminal of the detection circuit, the input terminal of the differential integration circuit and the ground terminal, and the second switching circuit is used for turning on or off all The electrical connection between the second input terminal of the detection circuit and the input terminal of the differential integration circuit, and turning on or off the connection between the second input terminal of the detection circuit and the ground terminal electrical connection between. The third switching circuit is coupled to the input terminal of the differential integration circuit and an operating voltage higher than the ground terminal, and the third switching circuit is used to turn on or off the input of the differential integration circuit electrical connection between the terminal and the operating voltage. The energy storage member has a first end and a second end. The fourth switching circuit is coupled to the first end of the energy storage element and the ground terminal, and the fourth switching circuit is used to turn on or off the first end of the energy storage element and the ground terminal. electrical connection between the ground terminals. The fifth switching circuit is coupled to the second end of the energy storage element, the ground terminal and the operating voltage, and the fifth switching circuit is used to turn on or off all the energy storage elements. The electrical connection between the second end and the ground end, and the electrical connection between the second end of the energy storage element and the operating voltage is turned on or off. The sixth switching circuit is coupled to the first end of the energy storage element and the input end of the differential integration circuit, and the sixth switching circuit is used to turn on or off the energy storage element. Electrical connection between the first terminal and the input terminal of the differential integration circuit.

Wherein the first switching circuit, the second switching circuit, the third switching circuit, the fourth switching circuit, the fifth switching circuit and the sixth switching circuit are used to detect the operation of the first The first stage is by distributing the charge in the energy storage element and the sensing capacitor so that the terminal voltage is related to the capacitance change due to the proximity of the human body and temperature, and in the second stage of the detection operation by distributing the The energy storage element and the charge in the sensing capacitor make the terminal voltage related to the capacitance change caused by temperature. The differential integrator circuit generates the result according to the difference between the voltage value of the input terminal of the differential integrator circuit in the first stage and the voltage value of the input terminal of the differential integrator circuit in the second stage. the detection voltage signal.

Another embodiment of the present application provides a chip including the detection circuit and the detection voltage signal reading circuit for reading the output of the detection circuit.

Another embodiment of the present application provides an electronic device including the detection circuit.

The detection circuit, chip and related electronic device of the present application can reduce the influence of temperature in the capacitance detection process, so that the effective sensing range of the detection voltage signal can be improved.

Description of drawings

FIG. 1 is a schematic diagram of prior art capacitive in-ear detection.

FIG. 2 is a diagram showing the relationship between the read voltage and the capacitance value in the prior art.

FIG. 3 is a schematic diagram of a detection circuit according to an embodiment of the present application.

FIG. 4 is a timing diagram of signals received and output by the detection circuit of FIG. 3 when performing a detection operation.

FIG. 5 is a comparison diagram of the detection voltage signal output by the detection circuit of FIG. 3 and the detection voltage signal of the prior art.

FIG. 6 is a schematic diagram of a detection circuit of another embodiment of the present application.

FIG. 7 is a timing diagram of signals received and output by the detection circuit of FIG. 6 when performing a detection operation.

Detailed ways

The following disclosure provides various implementations, or illustrations, that can be used to implement various features of the present disclosure. Specific examples of components and configurations are described below to simplify the present disclosure. As can be appreciated, these descriptions are exemplary only, and are not intended to limit the present disclosure. For example, in the description below, forming a first feature on or over a second feature may include some embodiments in which the first and second features are in direct contact with each other; and may also include Certain embodiments may have additional components formed between the first and second features described above, such that the first and second features may not be in direct contact. Furthermore, the present disclosure may reuse reference numerals and/or reference numerals in various embodiments. Such reuse is for brevity and clarity, and does not in itself represent a relationship between the different embodiments and/or configurations discussed.

Notwithstanding that the numerical ranges and parameters setting forth the broader scope of the application are approximations, the numerical values set forth in the specific examples have been reported as precisely as possible. Any numerical value, however, inherently contains the standard deviation resulting from individual testing methods. As used herein, "about" generally means within plus or minus 10%, 5%, 1%, or 0.5% of the actual value of a particular value or range. Alternatively, the word "about" means that the actual value lies within an acceptable standard error of the mean, as considered by one of ordinary skill in the art to which this application pertains. It should be understood that all ranges, quantities, numerical values and percentages used herein (for example, to describe material amounts, time durations, temperatures, operating conditions, quantity ratios and other similar) are modified by "about". Therefore, unless otherwise stated to the contrary, the numerical parameters disclosed in this specification and the accompanying claims are approximate numerical values and may be changed as required. At a minimum, these numerical parameters should be construed to mean the number of significant digits indicated and the numerical values obtained by applying ordinary rounding. Numerical ranges are expressed herein as from one endpoint to the other or between the endpoints; unless otherwise indicated, the numerical ranges recited herein are inclusive of the endpoints.

FIG. 1 is a schematic diagram of prior art capacitive in-ear detection. In FIG. 1 , the first end of the self-capacitance C _SF of the earphone may be the outer plate ET on the earphone casing, and the second end of the self-capacitance C _SF may be the inner plate IT on the earphone casing. Therefore, when someone wears the earphone, the ear will be in contact with the outer electrode plate ET. At this time, the human body equivalent capacitance CB will be connected in parallel with the self-capacitance C _SF through the outer electrode plate ET. In FIG. 1, the outer plate ET is connected to the reading circuit SC, and the inner plate IT is grounded. At this time, the voltage read by the reading circuit SC will be related to the capacitance change caused by the temperature and the human body equivalent capacitance _CB connected in parallel with the self-capacitance C _SF when the human body approaches.

However, since the voltage read by the read circuit SC is related to the capacitance change caused by temperature, the effective sensing range of the read voltage is limited to a certain extent. FIG. 2 is a diagram showing the relationship between the read voltage and the capacitance value in the prior art. In Figure 2, the range of the read voltage may be between V1 and V2. However, after deducting the capacitance change signal caused by temperature, it can actually be used to determine the effective sensing range of the capacitance value read due to the proximity of the human body to the earphone. Only between V3 and V4. Since the effective sensing range of the voltage read by the reading circuit SC is quite limited, the capacitive in-ear detection of the prior art may be inaccurate.

FIG. 3 is a schematic diagram of a detection circuit 100 according to an embodiment of the present application. In the embodiment of FIG. 3 , the detection circuit 100 can be coupled to the sensing capacitor C _S . Although the sensing capacitor C _S itself has an inherent capacitance value, when a human body approaches or the temperature changes, the detection circuit 100 senses The sensing capacitance value of the sensing capacitor C _S will vary, so the detection circuit 100 can detect the capacitance change through the sensing capacitor C _S to output the corresponding detection voltage signal VOUT. The inherent capacitance value of the sensing capacitor C _S itself refers to the inherent initial capacitance value of the sensing capacitor C _S when it is not affected by external changes. For example, when the human body is close to the sensing capacitor C _S , the human body equivalent capacitance CB will be connected in parallel with the sensing capacitor C _S. At this time, the sensing capacitance value of the sensing capacitor C _S will change, and the detection voltage signal will be detected. The value of VOUT will also change accordingly. In addition, the detection circuit 100 of the present application can eliminate the influence of temperature on the capacitance value of the sensing capacitor C _S before the reading circuit reads the detection voltage signal VOUT. Therefore, the effective dynamic range of the detection voltage signal VOUT is large, so that subsequent When judging whether there is a human body approaching the sensing capacitor _CS according to the detection voltage signal VOUT generated by the detection circuit 100, a more accurate result can be obtained, the details of which are described below.

In FIG. 3 , the detection circuit 100 may be disposed in a casing (not shown in the figure) of the electronic device, that is, the casing may enclose the detection circuit 100 . In this case, the sensing capacitance _CS can be, for example, but not limited to, a self-capacitance formed by electrodes on at least a part of the casing, wherein the electrodes on the casing can be existing conductive members on the casing, or It is an electrode specially set on the shell.

In addition, the first end of the sensing capacitor C _S may be located outside at least a portion of the casing, and the second end of the sensing capacitor C _S may be located inside at least a portion of the casing. The first end of the sensing capacitor C _S may be the outer plate of the casing, and the second end of the sensing capacitor C _S may be the inner plate of the casing. In this way, when the human body approaches the casing, the human body equivalent capacitance CB of the human body is coupled to the first end of the sensing capacitor _CS , so that the sensing capacitance value changes. In addition, the present application does not limit the sensing capacitor C _S to be a self-capacitance formed by the casing. In some other embodiments, the sensing capacitor C _S may also be the result of other components in the electronic device according to different usage scenarios. self-compassion formed. The human body approaching the earphone includes the human body approaching or touching the earphone.

The detection circuit 100 may include a first input terminal P1, a second input terminal P2, a first switching circuit SW1, a second switching circuit SW2, a third switching circuit SW3, a fourth switching circuit SW4, a fifth switching circuit SW5, and a sixth switching circuit Circuit SW6 , energy storage device A1 and differential integration circuit 110 .

The first input terminal P1 can be coupled to the first terminal of the sensing capacitor _CS , and the second input terminal P2 can be coupled to the second terminal of the sensing capacitor _CS . The detection circuit 100 _detects the sensing capacitance value of the sensing capacitor CS through the first input terminal P1 and the second input terminal P2.

The first switching circuit SW1 can be coupled to the first input terminal P1 , the input terminal NS1 of the differential integration circuit 110 and the ground terminal GND, and the first switching circuit SW1 can turn on or off the first input terminal P1 and the input of the differential integration circuit 110 The electrical connection between the terminals NS1 can turn on or off the electrical connection between the first input terminal P1 and the ground terminal GND.

The second switch circuit SW2 can be coupled to the second input terminal P2 , the input terminal NS1 of the differential integration circuit 110 and the ground terminal GND, and the second switch circuit SW2 can turn on or off the second input terminal P2 and the input of the differential integration circuit 110 The electrical connection between the terminals NS1 can turn on or off the electrical connection between the second input terminal P2 and the ground terminal GND.

The third switching circuit SW3 can be coupled to the input terminal NS1 of the differential integration circuit 110 and the operating voltage VDD higher than the ground terminal GND. The third switching circuit SW3 can turn on or off the input terminal NS1 of the differential integration circuit 110 and the operating voltage VDD. electrical connection between them. In the present application, the operating voltage VDD may be greater than the voltage of the ground terminal GND, such as but not limited to the power supply voltage or reference voltage provided in the system where the detection circuit 100 is located.

The energy storage element A1 has a first end and a second end, and the energy storage element A1 can provide a capacitance value matching the sensing capacitance _CS . The fourth switch circuit SW4 can be coupled to the first end of the energy storage element A1 and the ground terminal GND, and the fourth switch circuit SW4 can turn on or off the electrical connection between the first end of the energy storage element A1 and the ground terminal GND .

The fifth switching circuit SW5 can be coupled to the second terminal of the energy storage element A1, the ground terminal GND and the operating voltage VDD, and the fifth switching circuit SW5 can turn on or off between the second terminal of the energy storage element A1 and the ground terminal GND The electrical connection between the second end of the energy storage element A1 and the operating voltage VDD can be turned on or off. The sixth switching circuit SW6 can be coupled to the first end of the energy storage device A1 and the input end NS1 of the differential integration circuit 110 , and the sixth switching circuit SW6 can turn on or off the first end of the energy storage device A1 and the differential integration circuit 110 The electrical connection between the input terminals NS1.

The differential integration circuit 110 can be coupled to the common mode voltage VCM, and can integrate the voltage of the input terminal NS1 to generate the detection voltage signal VOUT when the detection circuit 100 performs the detection operation. In some embodiments, the differential integrating circuit 110 may include a differential amplifier 112, a first integrating capacitor C2, a second integrating capacitor C3, a seventh switching circuit SW7, an eighth switching circuit SW8, a ninth switching circuit SW9 and a tenth switching circuit SW10.

The differential amplifier 112 has a first input terminal, a second input terminal, a first output terminal and a second output terminal. In some embodiments, the first input terminal of the differential amplifier 112 may be a positive input terminal, the second input terminal of the differential amplifier 112 may be a negative input terminal, and the first output terminal of the differential amplifier 112 may be a positive output terminal and output a positive output voltage VPO, the second output terminal of the differential amplifier 112 can be a negative output terminal and can output a negative output voltage VNO, and the first output terminal and the second output terminal of the differential amplifier 112 can jointly output the detection voltage signal VOUT.

The first integrating capacitor C2 may have a first terminal and a second terminal, the first terminal of the first integrating capacitor C2 may be coupled to the first input terminal of the differential amplifier 110, and the second terminal of the first integrating capacitor C2 may be coupled to at the first output terminal of the differential amplifier 110 . The second integrating capacitor C3 has a first terminal and a second terminal. The first terminal of the second integrating capacitor C3 can be coupled to the second input terminal of the differential amplifier 112, and the second terminal of the second integrating capacitor C3 can be coupled to the second input terminal of the differential amplifier 112. The second output of the differential amplifier 112 .

The seventh switching circuit SW7 can be coupled to the first input terminal of the differential amplifier 112 and the input terminal NS1 of the differential integrating circuit 110 , and the seventh switching circuit SW7 can turn on or off the first input terminal of the differential amplifier 112 and the differential integrating circuit 110 The electrical connection between the input terminals NS1.

The eighth switching circuit SW8 can be coupled to the first input terminal of the differential amplifier 112 and the common mode voltage VCM, and the eighth switching circuit SW8 can turn on or off the power between the first input terminal of the differential amplifier 112 and the common mode voltage VCM. sexual connection.

The ninth switching circuit SW9 can be coupled to the second input terminal of the differential amplifier 112 and the input terminal NS1 of the differential integrating circuit 110 , and the ninth switching circuit SW9 can turn on or off the second input terminal of the differential amplifier 112 and the differential integrating circuit 110 The electrical connection between the input terminals.

The tenth switching circuit SW10 can be coupled to the second input terminal of the differential amplifier 112 and the common mode voltage VCM, and the tenth switching circuit SW10 can turn on or off the power between the second input terminal of the differential amplifier 112 and the common mode voltage VCM. sexual connection.

In FIG. 3 , the first switching circuit SW1 and the second switching circuit SW2 can turn on or off the corresponding electrical connections according to the first control signal K1 and the second control signal K2, and the third switching circuit SW3 and the fourth switching circuit The SW4 can turn on or turn off the corresponding electrical connection according to the third control signal K3. The fifth switching circuit SW5 can turn on or turn off the corresponding electrical connection according to the fourth control signal K4 and the fifth control signal K5. The sixth switching circuit SW6 can turn on or turn off the corresponding electrical connection according to the sixth control signal K6. The seventh switch circuit SW7 and the eighth switch circuit SW8 can turn on or off the corresponding electrical connection according to the seventh control signal K7 and the eighth control signal K8, respectively, and the ninth switch circuit SW9 and the tenth switch circuit SW10 can be respectively The corresponding electrical connections are turned on or off according to the eighth control signal K8 and the seventh control signal K7.

In this embodiment, the first switching circuit SW1 includes a first switch S1 and a second switch S2. The first switch S1 has a first terminal, a second terminal and a control terminal. The first terminal of the first switch S1 is coupled to the first input terminal P1 and the second terminal of the first switch S1 is coupled to the input of the differential integrating circuit 110 . terminal NS1. The second switch S2 has a first terminal, a second terminal and a control terminal. The first terminal of the second switch S2 is coupled to the first input terminal P1, and the second terminal of the second switch S2 is coupled to the ground terminal GND. In this way, the detection circuit has a simple structure, lower cost, lower power consumption and faster response.

The second switching circuit SW2 includes a third switch S3 and a fourth switch S4. The third switch S3 has a first terminal, a second terminal and a control terminal. The first terminal of the third switch S3 is coupled to the second input terminal P2 and the second terminal of the third switch S2 is coupled to the input of the differential integration circuit 110 terminal NS1. The fourth switch S4 has a first terminal, a second terminal and a control terminal, the first terminal of the fourth switch S4 is coupled to the second input terminal P2, and the second terminal of the fourth switch SW2 is coupled to the ground terminal GND. In this way, the detection circuit has a simple structure, lower cost, lower power consumption and faster response.

The fifth switching circuit SW5 includes a fifth switch S5 and a sixth switch S6. The fifth switch S5 has a first terminal, a second terminal and a control terminal, the first terminal of the fifth switch S5 is coupled to the second terminal of the energy storage element A1, and the second terminal of the fifth switch S5 is coupled to the operating voltage VDD . The sixth switch S6 has a first terminal, a second terminal and a control terminal, the first terminal of the sixth switch S6 is coupled to the second terminal of the energy storage element A1, and the second terminal of the sixth switch S6 is coupled to the ground terminal GND . In this way, the detection circuit has a simple structure, lower cost, lower power consumption and faster response.

In addition, the third switching circuit SW3, the fourth switching circuit SW4, the sixth switching circuit SW6, the seventh switching circuit SW7, the eighth switching circuit SW8, the ninth switching circuit SW9 and the tenth switching circuit SW10 can be implemented by a single switch, respectively. do. In this way, the detection circuit has a simple structure, lower cost, lower power consumption and faster response.

In this embodiment, when the control signal K1 is at a high level, the first switching circuit SW1 conducts the electrical connection between the first input terminal P1 and the input terminal NS1 of the differential integrating circuit 110 , and the second switching circuit SW2 The electrical connection between the second input terminal P2 and the ground terminal GND is turned on. When the control signal K2 is at a high level, the first switching circuit SW1 turns on the electrical connection between the first input terminal P1 and the ground terminal GND, and the second switching circuit SW2 turns on the second input terminal P2 and the differential integration Electrical connection between the input terminals NS1 of the circuit 110 .

In addition, when the control signals K3 to K8 are at a high level, the switching circuits SW3 to SW10 turn on the corresponding electrical connections, and when the control signals K3 to K8 are at a low level, the switching circuits SW3 to SW10 turn off the corresponding electrical connections Electrical connection. However, the present application does not limit the switching circuits SW1 to SW10 to conduct corresponding electrical connections when the control signals K1 to K8 are at a high potential.

In FIG. 4, the detection operation may include a first stage ST1 and a second stage ST2, the first stage ST1 may include a first period TP1, a second period TP2 and a third period TP3, and the second stage ST2 may include a fourth period TP4, the fifth period TP5 and the sixth period TP6.

In the first stage _ST1 , the detection circuit 100 can charge the sensing capacitor CS and the energy storage device A1 to a specific state, respectively, and make the sensing capacitor _CS and the energy storage device A1 jointly coupled to the differential integration circuit 110 . The input terminal NS1 enables redistribution of the internal charges of the sensing capacitor _CS and the energy storage element A1. In the first stage ST1, the first input terminal P1 is coupled to the operating voltage VDD, and the second input terminal P2 is coupled to the ground terminal GND. Under the condition that the capacitance value of the energy storage element A1 matches the inherent capacitance value of the sensing capacitor C _S , the voltage of the input terminal NS1 of the differential integrator circuit 110 will only be related to the capacitance change caused by the proximity of the human body and the temperature. Regardless of the inherent capacitance of the sensing capacitor C _S and the capacitance of the energy storage element A1 , the differential integrator 110 integrates on the first integrating capacitor C2 according to the voltage at the input NS1 of the differential integrating circuit 110 . Details about the conditions for matching the sensing capacitor C _S to the energy storage element A1 will be described later.

Next, in the second stage ST2, the detection circuit 100 charges the sensing capacitor C _S and the energy storage element A1, and makes the sensing capacitor C _S and the energy storage element A1 jointly coupled to the input end of the differential integrating circuit 110 NS1, so that the internal charge of the sensing capacitor _CS and the energy storage element A1 can be redistributed. However, in the second stage ST2, the first input terminal P1 is coupled to the ground terminal GND, and the second input terminal P2 is coupled to the operating voltage VDD. Since the human body is usually in a grounded state, when the human body is close to the first input terminal P1, both ends of the human body equivalent capacitance C _B will be in a grounded state. In this case, the human body equivalent capacitance C _B will not cause inductance. Change in capacitance value. In this way, under the condition that the inherent capacitance value of the sensing capacitor C _S matches the capacitance value of the energy storage element A1 , the voltage of the input terminal NS1 of the differential integrator circuit 110 will only be related to the capacitance change caused by temperature. , and has nothing to do with the inherent capacitance value of the sensing capacitor C _S and the capacitance value of the energy storage element A1 . In addition, in the second stage ST2 , the differential integrator 110 performs integration on the second integration capacitor C3 according to the voltage of the input terminal NS1 of the differential integration circuit 110 .

Since the first stage ST1 and the second stage ST2 perform charge integration on the positive input terminal and the negative input terminal of the differential amplifier 112 respectively, the detection voltage signal VOUT outputted when the second stage ST2 is completed will be two-stage The result of charge integral subtraction. That is, the differential integrator circuit 110 generates the detection voltage signal according to the difference between the voltage value of the input terminal NS1 of the differential integrator circuit 110 in the first stage and the voltage value of the input terminal NS1 of the differential integrator circuit 110 in the second stage. Ideally, in the first stage ST1 and the second stage ST2, the errors caused by the capacitance change caused by temperature will cancel each other out, so when the second stage ST2 is completed, the detection voltage signal VOUT will only be the same as that of the human body, etc. It is related to the capacitance change caused by the effective capacitance _CB . In this way, the detection voltage signal VOUT does not include the useless capacitance signal caused by temperature, but is only related to the effective capacitance signal caused by the proximity of the human body, so the detection voltage signal VOUT can provide a more accurate reference value.

In addition, the reading circuit for reading the detection voltage signal VOUT usually includes an analog-digital converter, so the detection circuit 100 can continuously perform multiple detection operations according to the voltage specification required by the analog-to-digital conversion circuit , so as to gradually integrate the detection voltage signal VOUT to a predetermined detection range suitable for the operation of the analog-to-digital conversion circuit according to the sensing capacitance value.

Furthermore, since the detection circuit 100 has automatically canceled the capacitance change caused by temperature when outputting the detection voltage signal VOUT, it is not necessary to reserve space for the temperature caused by the subsequent use of the analog-to-digital conversion circuit to interpret the value. In other words, the entire value of the detection voltage signal VOUT can be effectively used to interpret the capacitance change caused by the proximity of the human body, thereby increasing the range of effectively judging reading values, that is, to achieve the purpose of increasing the effective sensing range, and This avoids saturation of the analog-to-digital converter in the readout circuit.

Steps S310 to S315 may be included in the first period TP1 of the first stage ST1.

S310: Make the first switching circuit SW1 turn on the electrical connection between the first input terminal P1 and the input terminal NS1 of the differential integrating circuit 110, and turn off the electrical connection between the first input terminal P1 and the ground terminal GND;

S311: Make the second switching circuit SW2 turn off the electrical connection between the second input end P2 and the input end NS1 of the differential integrating circuit 110, and turn on the electrical connection between the second input end P2 and the ground end GND;

S312: Make the third switching circuit SW3 conduct the electrical connection between the input terminal NS1 of the differential integration circuit 110 and the operating voltage VDD;

S313: Make the fourth switching circuit SW4 conduct the electrical connection between the first end of the energy storage element A1 and the ground end GND;

S314: Make the fifth switching circuit SW5 turn off the electrical connection between the second end of the energy storage element A1 and the ground terminal GND, and turn on the electrical connection between the second end of the energy storage element A1 and the operating voltage VS2; and

S315 : Turn off the electrical connection between the first end of the energy storage device A1 and the input end NS1 of the differential integrating circuit 110 by the sixth switching circuit SW6 .

After completing steps S310 to S315, the first end of the energy storage element A1 is coupled to the ground terminal GND, and the second end of the energy storage element A1 is coupled to the operating voltage VDD; the first end of the sensing capacitor C _S It is coupled to the operating voltage VDD, and the second terminal of the sensing capacitor _CS is coupled to the ground terminal GND. At this time, the energy storage device A1 and the sensing capacitor _CS will be charged accordingly.

In the first stage ST1, steps S320 to S323 may be included in the second period TP2 following the first period TP1.

S320: Turn off the electrical connection between the input terminal NS1 of the differential integration circuit 110 and the operating voltage VDD by the third switching circuit SW3;

S321: Make the fourth switching circuit SW4 cut off the electrical connection between the first end of the energy storage element A1 and the ground end GND;

S322: Make the sixth switching circuit SW6 conduct the electrical connection between the first end of the energy storage element A1 and the input end NS1 of the differential integrating circuit 110; and

S323: Make the fifth switching circuit SW5 turn on the electrical connection between the second end of the energy storage element A1 and the ground terminal GND, and turn off the electrical connection between the second end of the energy storage element A1 and the operating voltage VDD, The sense capacitance CS is _{redistributed} with the charge in the energy storage device A1.

That is to say, in the second time period TP2 after the first time period TP1, the first end of the sensing capacitor _CS and the first end of the energy storage element A1 are both coupled to the input end NS1 of the differential integrating circuit 110, so the sense The charge in the sensing capacitor _CS and the energy storage device A1 will be redistributed, and the terminal voltage V _X of the input terminal NS1 of the differential integrator circuit 110 can be expressed as equation (1), where C1 is the capacitance value of the energy storage device A1.

Under the condition that the sensing capacitor _CS matches the energy storage element A1, the terminal voltage V _X will be independent of the sensing capacitor _CS and the capacitance value C1 of the energy storage element A1. For example, if the capacitance value C1 of the energy storage element A1 is one third of the inherent capacitance value of the sensing capacitor _CS , then the equation (1) can be rewritten as the equation (2).

That is to say, the terminal voltage V _X of the input terminal NS1 of the differential integrating circuit 110 may be substantially equal to 1/2 times the operating voltage VDD. In some embodiments, the common mode voltage VCM may also be equal to 1/2 times the operating voltage VDD.

In some embodiments, since the detection circuit 100 and the casing may be manufactured or designed by different manufacturers, it may not be possible to predict the size of the sensing capacitor C _S when the detection circuit 100 is fabricated. In this case, the energy storage device A1 may include a variable capacitor or a capacitor array. In this way, after the user knows the size of the sensing _capacitor _CS , he can And set the capacitance value of the variable capacitor or capacitor array through the control signal, so that the capacitance value C1 of the energy storage element A1 can be matched with the sensing capacitor C _S , for example, the capacitance value C1 of the energy storage element A1 is about the same as the sensing capacitance C S. One-third of the inherent capacitance value of the measuring capacitor C _S. In this way, the terminal voltage V _X of the input terminal NS1 of the differential integrator circuit 110 can be kept close to half of the operating voltage VDD, so that the accuracy of the detection circuit 100 will not be affected by the difference of the sensing capacitor C _S . The inherent capacitance value is affected by different sizes.

In addition, in FIG. 4 , the sixth control signal K6 changes from a low level to a high level after the third control signal K3 changes from a high level to a low level, and the fourth control signal K4 changes from a low level to a high level after the sixth control signal K6 The low potential is changed from the high potential to the low potential, so as to ensure that the charges in the sensing capacitor _CS and the energy storage device A1 are not transferred to the outside during redistribution. However, the present application is not limited to this. In some embodiments, when the third control signal K3 changes from a high level to a low level, the sixth control signal K6 can simultaneously change from a low level to a high level, and when the sixth control signal K3 changes from a high level to a low level at the same time When the control signal K6 changes from a low level to a high level, the fourth control signal K4 can also change from a high level to a low level at the same time. In some embodiments, the fourth control signal K4 and the fifth control signal K5 may be complementary control signals, so the fourth control signal K4 and the fifth control signal K5 also change potentials synchronously.

In the first stage ST1, steps S330 to S331 may be included in the third period TP3 following the second period TP2.

S330: Make the seventh switching circuit SW7 turn on the electrical connection between the first input terminal of the differential amplifier 110 and the input terminal NS1 of the differential integrating circuit 110; and

S331 : Make the tenth switching circuit SW10 conduct the electrical connection between the second input terminal of the differential amplifier 110 and the common mode voltage VCM, so as to perform integration through the first integrating capacitor C2 .

In the third period TP3 after the second period TP2, the first input terminal of the differential amplifier 112 may be coupled to the input terminal NS1 of the differential integrating circuit 110, and the second input terminal of the differential amplifier 112 may be coupled to the common mode voltage VCM, and can be integrated through the first integrating capacitor C2. In the third period TP3, the length of time that the seventh control signal K7 is at a high level is related to the integration time required by the first integrating capacitor C2. For example, the time when the seventh control signal K7 is at a high level The length may be set to be greater than or equal to a time length sufficient for the first integration capacitor C2 to complete the integration and for the voltage VPO of the first output terminal of the differential amplifier 112 to become stable.

In an ideal situation, that is, when there is no capacitance change caused by temperature or the proximity of the human body, and the inherent capacitance value of the sensing capacitor C _S matches the capacitance value of the energy storage element A1, the input terminal NS1 of the differential integrating circuit 110 The terminal voltage V _X will be equal to 1/2 times of VDD, which is the same as the common mode voltage VCM, and there will be no charge transfer in the first integrating capacitor C2 at this time.

However, when a human body approaches and/or a temperature change causes a change in the sensing capacitance value, the human body equivalent capacitance CB and the capacitance change value ΔC _T caused by the temperature will cause the first input terminal P1 and the second input terminal P1 to change. The sensed capacitance value sensed between the terminals P2 changes, and the terminal voltage V _X also changes accordingly, resulting in part of the charge moving into or out of the first integrating capacitor C2, where the amount of transferred charge ΔQ1 can be expressed as ( 3) indicates.

In this case, after the first stage _ST1 of the detection operation ends, the voltage VPO of the first output terminal of the differential amplifier 112 will be caused by the human body equivalent capacitance _CB connected in parallel with the sensing capacitance CS when the human body approaches and the temperature The capacitance change value ΔC _T is increased by the influence, and the voltage VNO of the second output terminal of the differential amplifier 112 will have an equal and opposite change. In FIG. 4 , the dotted line parts of the voltages VPO and VNO are the voltages output by the first output terminal and the second output terminal of the differential amplifier 112 under the condition that the capacitance changes due to temperature but no human body approaches, while the voltages VPO and VNO The solid line part of is the voltage output by the first output terminal and the second output terminal of the differential amplifier 112 under the condition that the capacitance changes due to the temperature and the proximity of a human body.

Steps S340 to S345 may be included in the fourth period TP4 of the second stage ST2.

S340: Make the first switching circuit SW1 turn off the electrical connection between the first input terminal and the input terminal NS1 of the differential integration circuit 110, and turn on the electrical connection between the first input terminal and the ground terminal GND;

S341: Make the second switching circuit SW2 turn on the electrical connection between the second input terminal and the input terminal NS1 of the differential integrating circuit 110, and turn off the electrical connection between the second input terminal and the ground terminal GND;

S342: Make the third switching circuit SW3 turn on the electrical connection between the input terminal NS1 of the differential integration circuit 110 and the operating voltage VDD, so that the sensing capacitor _CS is charged to the operating voltage VDD;

S343: Make the fourth switching circuit SW4 conduct the electrical connection between the first end of the energy storage element A1 and the ground end GND;

S344: Make the fifth switching circuit SW5 turn off the electrical connection between the second end of the energy storage element A1 and the ground terminal GND, and turn on the electrical connection between the second end of the energy storage element A1 and the operating voltage VDD; and

S345: Turn off the electrical connection between the first end of the energy storage element A1 and the input end NS1 of the differential integrating circuit 110 by the sixth switching circuit SW6.

After steps S340 to S345 are completed, the first end of the energy storage element A1 is coupled to the ground terminal GND, and the second end of the energy storage element A1 is coupled to the operating voltage VDD; the first end of the sensing capacitor C _S is coupled to the ground terminal GND, and the second terminal of the sensing capacitor _CS is coupled to the operating voltage VDD. At this time, the energy storage device A1 and the sensing capacitor _CS will be charged accordingly. In addition, in the fourth period TP4 of the second stage ST2, the seventh switching circuit SW7 to the tenth switching circuit SW10 all turn off the corresponding electrical connections.

In the second stage ST2, steps S350 to S353 may be included in the fifth period TP5 following the fourth period TP4.

S350: Turn off the electrical connection between the input end NS1 of the differential integration circuit 110 and the operating voltage VDD by the third switching circuit SW3;

S351: Make the fourth switching circuit SW4 cut off the electrical connection between the first end of the energy storage element A1 and the ground end GND;

S352: Make the sixth switching circuit SW6 conduct the electrical connection between the first end of the energy storage element A1 and the input end NS1 of the differential integrating circuit 110; and

S353: Make the fifth switching circuit SW5 turn on the electrical connection between the second end of the energy storage element A1 and the ground terminal GND, and turn off the electrical connection between the second end of the energy storage element A1 and the operating voltage VDD, The sense capacitance CS is _{redistributed} with the charge in the energy storage device A1.

In the fifth time period TP5 after the fourth time period TP4, the first end of the sensing capacitor C _S and the first end of the energy storage element A1 are both coupled to the input end NS1 of the differential integrating circuit 110, so the sensing capacitor C _S The charge in the energy storage element A1 will be redistributed, and the terminal voltage V _X of the input terminal NS1 of the differential integration circuit 110 is still expressed as equation (1). In the case where the sensing capacitor C _S matches the energy storage element A1, for example, when the capacitance value C1 of the energy storage element A1 is one third of the inherent capacitance value of the sensing capacitor C _S , the terminal voltage V _X can be rewritten is formula (2).

In the second stage ST2, steps S360 to S361 may be included in a sixth period TP6 following the fifth period TP5.

S360: Make the eighth switching circuit SW8 turn on the electrical connection between the first input terminal of the differential amplifier 110 and the common mode voltage VCM; and

S361 : Make the ninth switching circuit SW9 conduct the electrical connection between the second input terminal of the differential amplifier 110 and the input terminal NS1 of the differential integrating circuit 110 , so as to perform integration through the second integrating capacitor C3 .

In the sixth period TP6 after the fifth period TP5, the first input terminal of the differential amplifier 112 may be coupled to the common mode voltage VCM, and the second input terminal of the differential amplifier 112 may be coupled to the input terminal of the differential integrating circuit 110 NS1, and can be integrated through the second integrating capacitor C3. In an ideal situation, if the sensing capacitor C _S matches the capacitance value C1 of the energy storage element A1, the terminal voltage V _X of the input terminal NS1 of the differential integrator circuit 110 will be equal to 1/2 times VDD, which is different from the common mode The voltage VCM is the same, and there will be no charge transfer in the second integrating capacitor C3 at this time.

In addition, in the fourth period TP4, since the first input terminal P1 is coupled to the ground terminal GND through the first switching circuit SW1, even when a human body is close to the first input terminal P1, the equivalent capacitance of the human body Both ends of C _B will be grounded without affecting the sensing capacitance value. However, when there is a temperature change, the capacitance change value ΔC _T caused by the temperature will still cause the sensing capacitance value sensed between the first input terminal P1 and the second input terminal P2 to change. At this time, the terminal voltage V _X It will also change accordingly, causing part of the charge to move into or out of the second integrating capacitor C3, where the amount of charge ΔQ2 transferred can be expressed as equation (4).

That is to say, after the second stage ST2 of the detection operation ends, the voltage VNO of the second output terminal of the differential amplifier 112 will be boosted due to the charge transfer caused by the capacitance change value ΔC _T caused by the temperature, while the voltage of the differential amplifier 112 The voltage VPO of the first output terminal will have an equal and opposite change. Since the amount of transferred charge _ΔQ2 generated in the second stage ST2 is only related to the capacitance change caused by the temperature and has nothing to do with the equivalent capacitance CB of the human body connected in parallel to the sensing capacitor CS when the human body is close, therefore, in the case of no human body approaching , the part of the voltage VPO of the first output terminal of the differential amplifier 112 that originally increased due to the capacitance change caused by temperature in the first stage ST1 will cancel the part that decreased due to the capacitance change caused by temperature in the second stage ST2, as shown in FIG. 4 . shown by the dotted line.

In contrast, in the case of a human body approaching, the part of the voltage VPO of the first output terminal of the differential amplifier 112 that originally increased due to the capacitance change caused by temperature in the first stage ST1 will be different from that caused by temperature in the second stage ST2. The part that decreases due to the capacitance change cancels out, but the part of the voltage VPO of the first output terminal of the differential amplifier 112 that rises in the first stage ST1 because the human body is connected in parallel to the human body equivalent capacitance CB of the sensing capacitor C _S when the human body approaches it will not be cancel, so in FIG. 4, the solid line used to represent the voltage VPO does not completely drop to the common mode voltage VCM after the second stage ST2 is completed.

In some embodiments, after the second stage ST2 is completed, the voltage VPO of the first output terminal of the differential amplifier 112 can be expressed by equation (5). In this case, the detection voltage signal VOUT output by the detection circuit 100 can be represented by the formula (6).

That is to say, after the second stage ST2 of the detection operation is completed, the error of the detection voltage signal VOUT caused by the temperature-induced capacitance change will be compensated, so the detection voltage signal VOUT can more accurately represent the sensitivity of the detection voltage signal VOUT when the human body approaches. changes caused by the capacitance value.

In some embodiments, the detection circuit 100 can continuously perform multiple detection operations, so that the detection voltage signal can be gradually integrated to a predetermined detection range. For example, after the detection circuit 100 continuously performs detection operations M times, the detection voltage signal VOUT will become M·VDD(C _B /C2 ). In this way, the detection voltage signal VOUT can be adjusted to an appropriate value range by adjusting the number of executions, so that the subsequent circuit for interpretation, such as but not limited to an analog-to-digital converter, can more accurately interpret the data.

FIG. 5 is a comparison diagram of the detection voltage signal VOUT output by the detection circuit 100 and the detection voltage signal VPR of the prior art. In FIG. 5 , after the detection voltage signal VOUT goes through the operations of the first stage ST1 and the second stage ST2, the error in the detection voltage signal VOUT caused by the capacitance change caused by temperature is compensated, so the detection voltage signal VOUT can be It directly shows the change of the sensing capacitance value due to the proximity of the human body. In contrast, in the prior art, since the detection voltage signal VPR does not compensate the capacitance change caused by temperature before reading, the detection voltage signal VPR is not only related to the change of the sensing capacitance value caused by the proximity of the human body, but also Also related to temperature-induced capacitance changes. In addition, after multiple detection operations are performed continuously, the portion of the detection voltage signal VPR in the prior art related to the temperature-induced capacitance change will continue to be accumulated, resulting in a limited dynamic range of the read value.

However, since the detection circuit 100 can reduce the error caused by the capacitance change caused by the temperature in the detection voltage signal VOUT before the reading circuit reads the detection voltage signal VOUT, after several detection operations, the detection voltage signal VOUT It is still only related to the change in the sensing capacitance value caused by the proximity of the human body. In this way, the effective sensing range for interpreting the detection voltage signal VOUT can be increased, and during the in-ear test of the earphone, whether there is a human body approaching the earphone can be more accurately determined according to the detection voltage signal VOUT.

In FIG. 4 , the differential integration circuit 110 may further include a first reset switch RSW1 and a second reset switch RSW2. The first reset switch RSW1 can be coupled to the first input terminal of the differential amplifier 112 and the first output terminal of the differential amplifier 112 , and the first reset switch RSW1 can turn on the first input of the differential amplifier 112 during the reset operation. The electrical connection between the terminal and the first output terminal makes the first integrating capacitor C2 discharge. In addition, during the detection operation, the first reset switch RSW1 can cut off the electrical connection between the first input terminal and the first output terminal of the differential amplifier 112 , so that the first integrating capacitor C2 can subsequently perform the charge integration operation.

The second reset switch RSW2 can be coupled to the second input terminal and the second output terminal of the differential amplifier 112 , and the second reset switch RSW2 can turn on the second input terminal of the differential amplifier 112 and the differential amplifier 112 during the reset operation. The electrical connection between the second output terminals of , makes the second integrating capacitor C3 discharge. In addition, in the detection operation, the second reset switch RSW2 can turn off the electrical connection between the second input terminal and the second output terminal of the differential amplifier 112 , so that the second integrating capacitor C3 can subsequently perform the charge integration operation.

In the embodiment of FIG. 3 , the detection circuit 100 performs integration in the first stage ST1 and ST2 by setting the integration capacitors C2 and C3 at the positive input terminal and the negative input terminal of the differential amplifier 112 , respectively. However, the present application does not This is the limit. In some embodiments, the detection circuit 100 may also only set an integrating capacitor at one of the input terminals to perform integration. Furthermore, in some embodiments, the differential amplifier 112 of the detection circuit 100 may not be a fully differential amplifier, that is, the differential amplifier 112 may be a single-ended output.

FIG. 6 is a schematic diagram of a detection circuit 200 according to another embodiment of the present application. The detection circuit 200 and the detection circuit 100 have a similar structure and can operate according to similar principles, however, the detection circuit 200 may further include an eleventh switching circuit SW11 and a twelfth switching circuit SW12, and the differential integration circuit 210 of the detection circuit 200 It may include a differential amplifier 212, a first integrating capacitor C2 and a seventh switching circuit SW7.

The eleventh switching circuit SW11 can be coupled to the input terminal NS1 and the ground terminal GND of the differential integration circuit 210 , and the eleventh switching circuit SW11 can turn on or off the power between the input terminal NS1 and the ground terminal GND of the differential integration circuit 210 . sexual connection. The twelfth switch circuit SW12 can be coupled to the first end of the energy storage element A1 and the ground terminal GND, and the twelfth switch circuit SW12 can turn on or off the power between the first end of the energy storage element A1 and the operating voltage VDD sexual connection. The eleventh switching circuit SW11 and the twelfth switching circuit SW12 may be implemented by a single switch, respectively.

The differential amplifier 212 has a first input terminal, a second input terminal, a first output terminal and a second output terminal. The second input terminal of the differential amplifier 212 can be coupled to the common mode voltage VCM. The first output terminal of the differential amplifier 212 and The second output terminal may output the detection voltage signal VOUT. The first integrating capacitor C2 has a first terminal and a second terminal, the first terminal of the first integrating capacitor C2 can be coupled to the first input terminal of the differential amplifier 212, and the second terminal of the first integrating capacitor C2 can be coupled to the first input terminal of the differential amplifier 212. The first output of the differential amplifier 212 . The seventh switching circuit SW7 can be coupled to the first input terminal of the differential amplifier 212 and the input terminal NS1 of the differential integrating circuit 210 , and the seventh switching circuit SW7 can turn on or off the first input terminal of the differential amplifier 212 and the differential integrating circuit 210 The electrical connection between the input terminals NS1.

In FIG. 6 , the first switching circuit SW1 and the second switching circuit SW2 can turn on or off the corresponding electrical connections according to the first control signal K1 and the second control signal K2, and the third switching circuit SW3 and the fourth switching circuit The SW4 can turn on or turn off the corresponding electrical connection according to the third control signal K3. The fifth switching circuit SW5 can turn on or turn off the corresponding electrical connection according to the fourth control signal K4 and the fifth control signal K5. The sixth switching circuit SW6 can turn on or turn off the corresponding electrical connection according to the sixth control signal K6. The seventh switching circuit SW7 can turn on or turn off the corresponding electrical connection according to the seventh control signal K7. The eleventh switching circuit SW11 and the twelfth switching circuit SW12 can turn on or turn off the corresponding electrical connections according to the eleventh control signal K11 .

FIG. 7 is a timing diagram of signals received and output by the detection circuit 200 when performing the detection operation.

In some embodiments, when the control signal K1 is at a high level, the first switching circuit SW1 turns on the electrical connection between the first input terminal P1 and the input terminal NS1 of the differential integrating circuit 210 , and the second switching circuit SW2 The electrical connection between the second input terminal P2 and the ground terminal GND is turned on. When the control signal K2 is at a high level, the first switching circuit SW1 turns on the electrical connection between the first input terminal P1 and the input terminal NS1 of the differential integrating circuit 210 , and the second switching circuit SW2 turns on the second input The electrical connection between the terminal P2 and the ground terminal GND. In addition, when the control signals K3 to K7 are at a high level, the switching circuits SW3 to SW7 turn on the corresponding electrical connections, and when the control signals K3 to K7 are at a low level, the switching circuits SW3 to SW7 turn off the corresponding electrical connections. Electrical connection. When the control signal K11 is at a high level, the switching circuits SW11 and SW12 turn on the corresponding electrical connections, and when the control signal K11 is at a low level, the switching circuits SW11 and SW12 turn off the corresponding electrical connections. However, the present application does not limit the switching circuits SW1 to SW7, SW11 and SW12 to conduct corresponding electrical connections when the control signals K1 to K7 and K11 are at high potentials. When the control signals K1 to K7 and K11 are at a low level, the corresponding electrical connections are turned on, or the operation relationship between the control signals and the switching circuit is defined in other ways.

In FIG. 7, the detection operation may include a first stage ST1 and a second stage ST2, the first stage ST1 may include a first period TP1, a second period TP2 and a third period TP3, and the second stage ST2 may include a fourth period TP4, the fifth period TP5 and the sixth period TP6.

In the first stage _ST1 , the detection circuit 200 can charge the sensing capacitor CS and the energy storage device A1 to a specific state, respectively, and make the sensing capacitor _CS and the energy storage device A1 jointly coupled to the differential integration circuit 210 . The input terminal NS1 enables redistribution of the internal charges of the sensing capacitor _CS and the energy storage element A1. Under the condition that the inherent capacitance value of the sensing capacitor C _S matches the capacitance value of the energy storage element A1 , the voltage of the input terminal NS1 of the differential integrator circuit 210 will only match the capacitance caused when the human body approaches the first input terminal P1 The change is related to the capacitance change caused by temperature. At this time, the differential integrator 210 will perform integration on the first integration capacitor C2 according to the voltage of the input terminal NS1 of the differential integration circuit 210 .

Next, in the second stage ST2, the detection circuit 200 charges the sensing capacitor _CS and the energy storage device A1. Next, the detection circuit 200 can enable the sensing capacitor _CS and the energy storage element A1 to be coupled to the input terminal NS1 of the differential integration circuit 210. At this time, the internal charges of the sensing capacitor _CS and the energy storage element A1 will be redistributed. . Since in the second stage ST2, the first input terminal P1 will be coupled to the ground terminal GND, and the human body is usually in a grounded state, so in the second stage ST2, when the human body is close to the first input terminal P1, the human body, etc. Both ends of the effective capacitor C _B will be grounded. In this case, the human body equivalent capacitance C _B connected in parallel with the sensing capacitance C _S does not cause a change in the sensing capacitance value. In this way, under the condition that the inherent capacitance value of the sensing capacitor C _S matches the capacitance value of the energy storage element A1 , the voltage of the input terminal NS1 of the differential integrator circuit 210 will only be related to the capacitance change caused by temperature. , and has nothing to do with the human body equivalent capacitance C _B connected in parallel with the sensing capacitance C _S when the human body is close to the first input end P1 .

In addition, in the first stage ST1 and the second stage ST2, the charging direction of the energy storage device A1 is opposite, so when integrating the first integrating capacitor C2 of the differential integrator 210, the direction of charge transfer is also opposite. That is to say, when the second stage ST2 is completed, the detection voltage signal VOUT output by the detection circuit 200 will be the result of the two-stage charge integration and subtraction. Ideally, in the first stage ST1 and the second stage ST2 , because the errors caused by the capacitance change caused by temperature will cancel each other out, so the detection voltage signal VOUT is only related to the capacitance change caused by the human body equivalent capacitance _CB . In this way, the detection voltage signal VOUT can provide a more accurate reference value, reduce errors caused by capacitance changes caused by temperature, and further increase the effective sensing range for the detection voltage signal VOUT to be interpreted.

Steps S410 to S417 may be included in the first period TP1 of the first stage ST1.

S410: Turn on the electrical connection between the first input terminal and the input terminal NS1 of the differential integration circuit 210 by the first switching circuit SW1, and turn off the electrical connection between the first input terminal and the ground terminal GND;

S411: Make the second switching circuit SW2 turn off the electrical connection between the second input terminal and the input terminal NS1 of the differential integrating circuit 210, and turn on the electrical connection between the second input terminal and the ground terminal GND;

S412: Make the third switching circuit SW3 turn on the electrical connection between the input terminal NS1 of the differential integration circuit 210 and the operating voltage VDD, so that the sensing capacitor _CS is charged to the operating voltage VDD;

S413: Make the fourth switching circuit SW4 conduct the electrical connection between the first end of the energy storage element A1 and the ground end GND;

S414: Make the fifth switching circuit SW5 turn off the electrical connection between the second end of the energy storage element A1 and the ground terminal GND, and turn on the electrical connection between the second end of the energy storage element A1 and the operating voltage VDD;

S415: Make the sixth switching circuit SW6 turn off the electrical connection between the first end of the energy storage element A1 and the input end NS1 of the differential integrating circuit 210;

S416: Make the eleventh switching circuit SW11 turn off the electrical connection between the input terminal NS1 of the differential integration circuit 210 and the ground terminal GND; and

S417: Turn off the electrical connection between the first end of the energy storage device A1 and the operating voltage VDD by the twelfth switching circuit SW12.

After steps S410 to S418 are completed, the first end of the energy storage element A1 is coupled to the ground terminal GND, and the second end of the energy storage element A1 is coupled to the operating voltage VDD; the first end of the sensing capacitor C _S It is coupled to the operating voltage VDD, and the second terminal of the sensing capacitor _CS is coupled to the ground terminal GND. At this time, the energy storage device A1 and the sensing capacitor _CS will be charged accordingly.

In the first stage ST1, steps S420 to S423 may be included in the second period TP2 following the first period TP1.

S420: Turn off the electrical connection between the input terminal NS1 of the differential integration circuit 210 and the operating voltage VDD by the third switching circuit SW3;

S421: Make the fourth switching circuit SW4 cut off the electrical connection between the first end of the energy storage element A1 and the ground end GND;

S422: Make the sixth switching circuit SW6 conduct the electrical connection between the first end of the energy storage element A1 and the input end NS1 of the differential integrating circuit 210; and

S423: Make the fifth switching circuit SW5 turn on the electrical connection between the second end of the energy storage element A1 and the ground terminal GND, and turn off the electrical connection between the second end of the energy storage element A1 and the operating voltage VDD, The sense capacitance CS is _{redistributed} with the charge in the energy storage device A1.

That is to say, in the second time period TP2 after the first time period TP1, the first end of the sensing capacitor _CS and the first end of the energy storage element A1 are both coupled to the input end NS1 of the differential integrating circuit 210, so the sense The charge in the sensing capacitor _CS and the energy storage device A1 will be redistributed. In this case, the operation of the detection circuit 200 in the periods TP1 and TP2 in FIG. 7 is similar to the operation of the detection circuit 100 in the periods TP1 and TP2 in FIG. 4 , so the terminal voltage of the input terminal NS1 of the differential integration circuit 210 of the detection circuit 200 is detected V _X can also be represented by the formula (1).

In addition, in the case that the sensing capacitor _CS matches the energy storage element A1, the terminal voltage V _X will be independent of the capacitance value C1 of the sensing capacitor _CS and the energy storage element A1. For example, if the capacitance value C1 of the energy storage device A1 is one third of the inherent capacitance value of the sensing capacitor C _S , the terminal voltage V _X of the input terminal NS1 of the differential integrating circuit 210 can be changed to Equation (2) express.

In the first stage ST1, step S430 may be included in a third period TP3 following the second period TP2.

S430 : Make the seventh switching circuit SW7 turn on the electrical connection between the first input terminal of the differential amplifier 110 and the input terminal NS1 of the differential integrating circuit 210 to perform integration through the first integrating capacitor C2 .

In the third period TP3 after the second period TP2, the first input terminal of the differential amplifier 212 may be coupled to the input terminal NS1 of the differential integrating circuit 210, and the first input terminal of the differential amplifier 212 may be coupled to the common mode voltage VCM, so the differential amplifier 212 can integrate through the first integrating capacitor C2. In an ideal situation, that is, when there is no capacitance change caused by temperature or the proximity of the human body, and the sensing capacitor C _S matches the energy storage device A1, the terminal voltage V _X of the input terminal NS1 of the differential integrator circuit 210 will be equal to 1/2 times of VDD, and the same as the common mode voltage VCM, at this time, no charge transfer will occur in the first integrating capacitor C2.

In FIG. 7 , the dotted line parts of the voltages VPO and VNO are the voltages output by the first output terminal and the second output terminal of the differential amplifier 212 under the condition that the capacitance changes due to temperature but no human body approaches, while the voltages VPO and VNO The solid line part of is the voltage output by the first output terminal and the second output terminal of the differential amplifier 212 when there is a temperature change and a human body is approaching.

Steps S440 to S447 may be included in the fourth period TP4 of the second stage ST2.

S440: Make the first switching circuit SW1 turn off the electrical connection between the first input terminal and the input terminal NS1 of the differential integration circuit 210, and turn on the electrical connection between the first input terminal and the ground terminal GND;

S441: make the second switching circuit SW2 conduct the electrical connection between the second input terminal and the input terminal NS1 of the differential integrating circuit 210, and cut off the electrical connection between the second input terminal and the ground terminal GND;

S442: Turn off the electrical connection between the input terminal NS1 of the differential integration circuit 210 and the operating voltage VDD by the third switching circuit SW3;

S443: Make the fourth switching circuit SW4 cut off the electrical connection between the first end of the energy storage element A1 and the ground end GND;

S444: Make the fifth switching circuit SW5 turn on the electrical connection between the second end of the energy storage element A1 and the ground terminal GND, and turn off the electrical connection between the second end of the energy storage element A1 and the operating voltage VDD;

S445: Make the sixth switching circuit SW6 turn off the electrical connection between the first end of the energy storage element A1 and the input end NS1 of the differential integrating circuit 210;

S446: Make the eleventh switching circuit SW11 conduct the electrical connection between the input terminal NS1 of the differential integration circuit 210 and the ground terminal GND, so that the sensing capacitor _CS is discharged to the ground terminal GND; and

S447: Make the twelfth switching circuit SW12 conduct the electrical connection between the first end of the energy storage device A1 and the operating voltage VDD.

After steps S440 to S447 are completed, the first end of the energy storage device A1 is coupled to the operating voltage VDD, and the second end of the energy storage device A1 is coupled to the ground terminal GND; the first end of the sensing capacitor C _S is coupled to the ground terminal GND, and the second terminal of the sensing capacitor _CS is coupled to the ground terminal GND. At this time, the energy storage device A1 and the sensing capacitor _CS will be charged accordingly.

In the second stage ST2, steps S450 to S453 may be included in the fifth period TP5 following the fourth period TP4.

S450: Turn off the electrical connection between the input terminal NS1 of the differential integration circuit 210 and the ground terminal GND by the eleventh switching circuit SW11;

S451: Make the twelfth switching circuit SW12 cut off the electrical connection between the first end of the energy storage device A1 and the operating voltage VDD;

S452: Make the sixth switching circuit SW6 conduct the electrical connection between the first end of the energy storage element A1 and the input end NS1 of the differential integrating circuit 210; and

S453: Make the fifth switching circuit SW5 turn off the electrical connection between the second end of the energy storage element A1 and the ground terminal GND, and turn on the second end of the energy storage element A1 and the operating voltage VDD

The electrical connection between them redistributes the charges in the sensing capacitor _CS and the energy storage element A1.

In the fifth time period TP5 after the fourth time period TP4, the first end of the sensing capacitor C _S and the first end of the energy storage element A1 are both coupled to the input end NS1 of the differential integrating circuit 210, so the sensing capacitor C _S The charge in the energy storage device A1 will be redistributed. Next, after the sixth switching circuit SW6 turns on the electrical connection between the first terminal of the energy storage element and the input terminal NS1 of the differential integrating circuit 210 , the fifth switching circuit SW5 can turn off the second terminal of the energy storage element A1 and the input terminal NS1 of the differential integrating circuit 210 . The electrical connection between the ground terminals GND can turn on the electrical connection between the second terminal of the energy storage element A1 and the operating voltage VDD. Since the second end of the energy storage device A1 will be raised to the operating voltage VDD, the voltage of the first end of the energy storage device A1 will also be raised to twice the operating voltage _2VDD . After the redistribution of the charges in the energy storage element A1 is completed, the terminal voltage V _X of the input terminal of the differential integration circuit 110 will finally be represented by equation (7).

In the case where the sensing capacitor C _S matches the energy storage element A1, for example, when the capacitance value C1 of the energy storage element A1 is one third of the inherent capacitance value of the sensing capacitor C _S , then equation (7) will It can be rewritten as formula (8).

In the fifth time period TP5 of FIG. 7 , the sixth control signal K6 changes from the low level to the high level after the eleventh control signal K11 changes from the high level to the low level, so as to ensure the sensing capacitor _CS and the energy storage. The charge in element A1 is not transferred to the outside during redistribution. However, in some embodiments, when the eleventh control signal K11 changes from a high level to a low level, the sixth control signal K6 can also change from a low level to a high level at the same time. In addition, the fourth control signal K4 changes from a low level to a high level after the sixth control signal K6 changes from a low level to a high level, so that the second end of the energy storage device A1 and the The potential of the second terminal can be further raised.

In the second stage ST2, steps S460 to S461 may be included in a sixth period TP6 following the fifth period TP5.

S460: Make the seventh switching circuit SW7 conduct the electrical connection between the first input terminal of the differential amplifier 212 and the input terminal NS1 of the differential integrating circuit 210, so as to integrate through the first integrating capacitor C2; and

S461: Enable the first output terminal and the second output terminal of the differential amplifier 212 to output the detection voltage signal VOUT.

In the sixth period TP6 after the fifth period TP5, the first input terminal of the differential amplifier 212 may be coupled to the input terminal NS1 of the differential integrating circuit 210, and the second input terminal of the differential amplifier 212 may be coupled to the common mode voltage VCM, and can be integrated through the first integrating capacitor C2. In an ideal situation, if the sensing capacitor C _S matches the energy storage device A1, the terminal voltage V _X of the input terminal NS1 of the differential integrator circuit 210 will be equal to 1/2 times of VDD, which is the same as the common mode voltage VCM, At this time, there will be no charge transfer in the first integrating capacitor C2.

In addition, since the first input terminal P1 is coupled to the ground terminal GND through the first switching circuit SW1 in the fourth period TP4, even when a human body approaches the first input terminal P1, the human body is equivalent to Both ends of the capacitor C _B will be grounded without affecting the sensing capacitance value. However, when there is a temperature change, the capacitance change value ΔC _T caused by the temperature will still cause the sensing capacitance value between the first input terminal P1 and the second input terminal P2 to change. At this time, the terminal voltage V _X will also change with The change causes part of the charge to move into or out of the first integrating capacitor C3, where the amount of charge ΔQ2 transferred can be expressed as Equation (9).

According to equation (9), it can be seen that the amount of transferred charge ΔQ2 generated in the second stage ST2 is negatively correlated with the capacitance change value ΔC _T caused by temperature, and the amount of transferred charge ΔQ2 is only related to the capacitance change caused by temperature and is related to the change in capacitance caused by temperature. When the human body approaches, it has nothing to do with the human body equivalent capacitance CB connected in parallel with the sensing capacitor C _S. Therefore, in the case of no human body approaching, the voltage VPO of the first output terminal of the differential amplifier 212 was originally changed in the first stage ST1 due to the capacitance change caused by the temperature. The rising part will cancel the falling part due to the temperature-induced capacitance change in the second stage ST2 , as shown by the dotted line in FIG. 7 .

In contrast, in the case of a human body approaching, the voltage VPO of the first output terminal of the differential amplifier 212 originally increased due to the capacitance change caused by temperature in the first stage ST1, although the capacitance change caused by temperature in the second stage ST2 will be different. However, the voltage VPO of the first output terminal of the differential amplifier 212 in the first stage ST1 and the rising part of the voltage VPO which is connected in parallel with the human body equivalent capacitance CB of the sensing capacitor C _S when the human body approaches, will not be cancelled. Therefore, in FIG. 7, after the second stage ST2 is completed, the solid line of the voltage VPO does not completely decrease to the common mode voltage VCM. Therefore, after the detection circuit 200 completes the second stage ST2 of the detection operation, the voltage VPO of the first output terminal of the differential amplifier 212 is still represented by the formula (5), and the detection voltage signal VOUT output by the detection circuit 200 can be expressed by the formula (6) indicates.

That is to say, after the second stage ST2 is completed, the error of the detection voltage signal VOUT caused by the capacitance change caused by temperature can be compensated, so that the change of the sensing capacitance value when the human body approaches can be more accurately represented.

In some embodiments, the detection circuit 200 can continuously perform multiple detection operations, so that the detection voltage signal can be gradually integrated to a predetermined detection range. For example, after the detection circuit 200 continuously performs detection operations M times, the detection voltage signal VOUT will become M·VDD(C _B /C2 ). In this way, the detection voltage signal VOUT can be adjusted to an appropriate value range by adjusting the number of executions, so that the subsequent circuit for interpreting can interpret the data more accurately.

In FIG. 6, the differential integration circuit 210 may further include a first reset switch RSW1. The first reset switch RSW1 can be coupled to the first input terminal and the first output terminal of the differential amplifier 212 , and the first reset switch RSW1 can turn on the first input terminal and the first output terminal of the differential amplifier 212 during the reset operation. The electrical connection between the output terminals makes the first integrating capacitor C2 discharge. In addition, in the detection operation, the first reset switch RSW1 can cut off the electrical connection between the first input terminal and the first output terminal of the differential amplifier 212 so that the first integrating capacitor C2 can perform the charge integration operation.

To sum up, the detection circuit provided by the embodiments of the present application can use the energy storage element matched with the sensing capacitor to compensate the temperature-induced capacitance change error before the detection voltage signal is read, so that the detection voltage signal is The change of the sensing capacitance value when the human body approaches can be presented more accurately. In this way, in the subsequent use of the analog-to-digital conversion circuit for numerical interpretation, the analog-to-digital conversion circuit does not need to reserve space for the capacitance change caused by temperature, so as to increase the effective sensing range of the analog-to-digital conversion circuit. The accuracy of the capacitance detection signal and the accuracy of subsequent application judgment based on the capacitance detection signal can be increased. For example, operations such as touch detection, capacitive in-ear detection, and capacitive pressure detection based on capacitive detection signals are more accurate.

The present application also provides a chip and an electronic device, such as an earphone. Since the voltage detection signal generated by the detection circuit in the chip and the electronic device can accurately represent the change of the sensing capacitance value when the human body approaches, without being disturbed by the temperature change, it can be used for capacitive touch detection , capacitive in-ear detection, capacitive pressure detection, etc., and the chip and electronic device of the present application can perform subsequent operations, such as answering a call, playing or pausing music, etc. according to different applications.

The foregoing description briefly sets forth features of certain embodiments of the application, so that those skilled in the art to which this application pertains can more fully understand the various aspects of the present disclosure. It should be apparent to those skilled in the art to which this application pertains that they can readily use the present disclosure as a basis to design or modify other processes and structures for carrying out the same purposes and/or of the embodiments described herein achieve the same advantages. Those with ordinary knowledge in the technical field to which this application belongs should understand that these equivalent embodiments still belong to the spirit and scope of the present disclosure, and various changes, substitutions and alterations can be made without departing from the spirit of the present disclosure. with scope.

Claims

A detection circuit, characterized in that it is coupled to a sensing capacitor, the sensing capacitor has an inherent capacitance value, and the sensing capacitance value of the sensing capacitor changes at least due to the proximity of a human body, and the detection circuit comprises:

a first input end coupled to the first end of the sensing capacitor;

a second input end coupled to the second end of the sensing capacitor;

a differential integrator circuit, having an input terminal, the differential integrator circuit is used for integrating according to the terminal voltage of the input terminal of the differential integrator circuit to generate a detection voltage signal when the detection circuit performs a detection operation;

a first switching circuit, coupled to the first input terminal of the detection circuit, the input terminal of the differential integration circuit and the ground terminal, the first switching circuit is used for turning on or off the detection circuit The electrical connection between the first input terminal of the differential integration circuit and the input terminal of the differential integration circuit, and the electrical connection between the first input terminal of the detection circuit and the ground terminal is turned on or off sexual connection;

A second switching circuit, coupled to the second input terminal of the detection circuit, the input terminal of the differential integration circuit and the ground terminal, the second switching circuit is used for turning on or off the The electrical connection between the second input terminal of the detection circuit and the input terminal of the differential integration circuit, and turning on or off the connection between the second input terminal of the detection circuit and the ground terminal the electrical connection;

a third switching circuit, coupled to the input terminal of the differential integration circuit and the operating voltage, the third switching circuit is used to turn on or off the relationship between the input terminal of the differential integration circuit and the operating voltage electrical connection between;

an energy storage member, having a first end and a second end;

A fourth switching circuit is coupled to the first end of the energy storage element and the ground terminal, and the fourth switching circuit is used to turn on or off the first end of the energy storage element and the ground terminal. The electrical connection between the ground terminals;

a fifth switching circuit, coupled to the second end of the energy storage element, the ground terminal and the operating voltage, the fifth switching circuit is used to turn on or off the energy storage element The electrical connection between the second terminal and the ground terminal, and the electrical connection between the second terminal of the energy storage element and the operating voltage is turned on or off; and

A sixth switching circuit is coupled to the first end of the energy storage element and the input end of the differential integration circuit, and the sixth switching circuit is used to turn on or off all the energy storage elements. an electrical connection between the first end and the input end of the differential integrating circuit;

in:

The first switching circuit, the second switching circuit, the third switching circuit, the fourth switching circuit, the fifth switching circuit and the sixth switching circuit are used in the first stage of the detection operation By distributing the charge in the energy storage element and the sensing capacitor, the terminal voltage is related to the capacitance change caused by the proximity of the human body and temperature, and in the second stage of the detection operation by distributing the storage energy and the charge in the sensing capacitor, so that the terminal voltage is related to the capacitance change due to temperature; and

The differential integrator circuit generates the result according to the difference between the voltage value of the input terminal of the differential integrator circuit in the first stage and the voltage value of the input terminal of the differential integrator circuit in the second stage. the detection voltage signal.
The detection circuit of claim 1, wherein the differential integration circuit comprises:

A differential amplifier has a first input terminal, a second input terminal, a first output terminal and a second output terminal, and the first output terminal and the second output terminal of the differential amplifier are used for outputting the detection voltage signal ;

The first integrating capacitor has a first end and a second end, the first end of the first integrating capacitor is coupled to the first input end of the differential amplifier, and the first integrating capacitor The second end is coupled to the first output end of the differential amplifier;

A second integrating capacitor has a first end and a second end, the first end of the second integrating capacitor is coupled to the second input end of the differential amplifier, and the second integrating capacitor The second end is coupled to the second output end of the differential amplifier;

a seventh switching circuit, coupled to the first input terminal of the differential amplifier and the input terminal of the differential integrating circuit, the seventh switching circuit is used to turn on or off the differential amplifier an electrical connection between the first input terminal and the input terminal of the differential integration circuit;

an eighth switching circuit, coupled to the first input terminal of the differential amplifier and a common-mode voltage, the eighth switching circuit is used to turn on or off the first input terminal of the differential amplifier and the common-mode voltage Electrical connection between common mode voltages;

a ninth switching circuit, coupled to the second input terminal of the differential amplifier and the input terminal of the differential integrating circuit, the ninth switching circuit is used to turn on or off the differential amplifier an electrical connection between the second input terminal and the input terminal of the differential integration circuit; and

A tenth switching circuit is coupled to the second input terminal of the differential amplifier and the common-mode voltage, and the tenth switching circuit is used to turn on or off the second input terminal of the differential amplifier and the common-mode voltage. electrical connection between the common mode voltages.
The detection circuit of claim 2, wherein the differential integrating circuit further comprises:

a first reset switch, coupled to the first input terminal of the differential amplifier and the first output terminal of the differential amplifier, the first reset switch is used for resetting the detection circuit In operation, the electrical connection between the first input terminal of the differential amplifier and the first output terminal of the differential amplifier is turned on, and in the detection operation, all of the differential amplifiers are turned off. the electrical connection between the first input and the first output of the differential amplifier; and

a second reset switch, coupled to the second input terminal of the differential amplifier and the second output terminal of the differential amplifier, the second reset switch is used for conducting the reset operation during the reset operation passing the electrical connection between the second input terminal of the differential amplifier and the second output terminal of the differential amplifier, and in the detection operation, turning off the second input of the differential amplifier The electrical connection between the terminal and the second output terminal of the differential amplifier.
The detection circuit of claim 1, wherein:

The differential integration circuit includes:

A differential amplifier has a first input terminal, a second input terminal, a first output terminal and a second output terminal, the second input terminal of the differential amplifier is coupled to a common-mode voltage, and the first input terminal of the differential amplifier an output terminal and the second output terminal are used for outputting the detection voltage signal;

A first integrating capacitor has a first end and a second end, the first end of the first integrating capacitor is coupled to the first input end of the differential amplifier, and all of the first integrating capacitor the second terminal is coupled to the first output terminal of the differential amplifier; and

a seventh switching circuit, coupled to the first input terminal of the differential amplifier and the input terminal of the differential integrating circuit, the seventh switching circuit is used to turn on or off the differential amplifier an electrical connection between the first input terminal and the input terminal of the differential integration circuit;

The detection circuit further includes:

An eleventh switching circuit is coupled to the input terminal and the ground terminal of the differential integration circuit, and the eleventh switching circuit is used to turn on or off the differential integration circuit. an electrical connection between the input terminal and the ground terminal; and

A twelfth switching circuit is coupled to the first end of the energy storage element and the ground terminal, and the twelfth switching circuit is used to turn on or off the first end of the energy storage element and the electrical connection between the operating voltages.
The detection circuit of claim 4, wherein the differential integrating circuit further comprises:

a first reset switch, coupled to the first input terminal of the differential amplifier and the first output terminal of the differential amplifier, the first reset switch is used to turn on all the electrical connection between the first input terminal of the differential amplifier and the first output terminal of the differential amplifier, and in the detection operation, turning off the first input terminal of the differential amplifier and the the electrical connection between the first output ends of the differential amplifier.
The detection circuit of any one of claims 1 to 5, wherein the first stage comprises: charging the sensing capacitor and the energy storage element, redistributing the sensing capacitor, and charge in the energy storage element such that the terminal voltage is independent of the intrinsic capacitance value of the sensing capacitor and the capacitance value of the energy storage element, and the terminal voltage is subjected to the redistribution after the redistribution integration, wherein the first input terminal of the detection circuit is coupled to the operating voltage and the second input terminal of the detection circuit is coupled to ground during charging, so that the terminal voltage It is related to the capacitance change caused by the proximity of the human body and temperature.
The detection circuit of any one of claims 1 to 5, wherein the second stage comprises: charging the sensing capacitor and the energy storage element, redistributing the sensing capacitor, and charge in the energy storage element such that the terminal voltage is independent of the intrinsic capacitance value of the sensing capacitor and the capacitance value of the energy storage element, and the terminal voltage is subjected to the redistribution after the redistribution integration, wherein the second input of the detection circuit is coupled to the operating voltage and the first input of the detection circuit is coupled to the ground during charging, so that the The terminal voltage is related to the capacitance change due to temperature.
The detection circuit according to any one of claims 1 to 5, wherein the capacitance value of the energy storage element is one third of the inherent capacitance value of the sensing capacitor.
The detection circuit according to any one of claims 1 to 5, wherein the energy storage element comprises a variable capacitor or a capacitor array, wherein the capacitance value of the variable capacitor or the capacitor array is determined by a control signal is changed according to the intrinsic capacitance value of the sensing capacitance.
The detection circuit of claim 1, wherein the first switching circuit comprises:

The first switch has a first end, a second end and a control end, the first end of the first switch is coupled to the first input end of the detection circuit, the first end of the first switch is The second terminal is coupled to the input terminal of the differential integrating circuit; and

A second switch has a first end, a second end and a control end, the first end of the second switch is coupled to the first input end of the detection circuit, the second switch The second terminal is coupled to the ground terminal.
The detection circuit according to claim 1 or 10, wherein the second switching circuit comprises:

A third switch has a first terminal, a second terminal and a control terminal, the first terminal of the third switch is coupled to the second input terminal of the detection circuit, and the The second terminal is coupled to the input terminal of the differential integrating circuit; and

The fourth switch has a first end, a second end and a control end, the first end of the fourth switch is coupled to the second input end of the detection circuit, the fourth switch The second terminal is coupled to the ground terminal.
The detection circuit according to claim 1 or 10, wherein the fifth switching circuit comprises:

The fifth switch has a first end, a second end and a control end, the first end of the fifth switch is coupled to the second end of the energy storage element, the fifth switch The second terminal is coupled to the operating voltage; and

The sixth switch has a first end, a second end and a control end, the first end of the sixth switch is coupled to the second end of the energy storage element, the The second terminal is coupled to the ground terminal.
A chip, comprising the detection circuit of any one of claims 1-12 and a reading circuit for reading a detection voltage signal output by the detection circuit.
An electronic device, comprising:

A detection circuit as claimed in any one of claims 1-12.