Capacitance detection circuit, chip and electronic equipment

Abstract

The invention provides a capacitance detection circuit, a chip and an electronic device, the circuit comprises a signal input module used for providing a reference voltage, a first preset excitation signal and a second preset excitation signal, and the reference voltage is provided by a voltage source; the detection module is used for gradually adjusting the capacitance value of the reference capacitor according to the first preset excitation signal in the first stage until the voltage output by the amplifier is matched with the preset voltage, and obtaining the output voltage of the amplifier according to the second preset excitation signal in the second stage; the control module is used for collecting the capacitance value of the reference capacitor and the output voltage of the amplifier in the first stage so as to obtain a voltage deviation value and the fixed capacitance value of the capacitor to be measured, and calculating the final capacitance value of the capacitor to be measured in the second stage according to the output voltage, the fixed capacitance value, the voltage deviation value and the reference voltage. According to the invention, a voltage source is provided as an excitation signal, large errors caused by introduction of multiple excitation sources in the detection process are reduced, and the precision of capacitance detection is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a capacitance detection circuit, a chip and an electronic device. Background Art

[0002] With the continuous development of artificial intelligence technology, the demand for inductive capacitance detection technology of electronic products is gradually increasing, and the requirements for the accuracy and speed of inductive capacitance detection are gradually increasing.

[0003] In existing capacitance detection technology, multiple excitation sources are usually introduced, which leads to more detection error sources, complex detection process, and difficulty in calibrating detection data. These factors will reduce the accuracy and speed of inductive capacitance detection.

[0004] Therefore, in order to reduce the complexity of the inductive capacitance detection process and improve the detection accuracy, it is necessary to develop efficient inductive capacitance detection technology to meet the increasing application needs of electronic products. Summary of the invention

[0005] The present invention provides a capacitance detection circuit, a chip and an electronic device, the main purpose of which is to reduce capacitance detection error and effectively improve capacitance detection accuracy.

[0006] In a first aspect, an embodiment of the present invention provides a capacitance detection circuit, including:

[0007] A signal input module, used for providing a reference voltage, a first preset excitation signal and a second preset excitation signal, wherein the reference voltage is provided by a voltage source;

[0008] A detection module including a reference capacitor and an amplifier, configured to gradually adjust the capacitance of the reference capacitor according to the first preset excitation signal in a first stage until the voltage output by the amplifier matches the preset voltage, and to obtain the output voltage of the amplifier according to the second preset excitation signal in a second stage;

[0009] The control module is used to collect the capacitance of the reference capacitor and the output voltage of the amplifier in the first stage to obtain the voltage deviation value and the fixed capacitance of the capacitor to be measured, and calculate the final capacitance of the capacitor to be measured according to the output voltage, the fixed capacitance, the voltage deviation value and the reference voltage in the second stage.

[0010] Furthermore, the detection module includes:

[0011] a switch branch, configured to present a first switch state according to the first preset excitation signal, and present a second switch state according to the second preset excitation signal;

[0012] A reference branch comprising the reference capacitor, configured to gradually adjust the capacitance of the reference capacitor in the first switching state until the voltage output by the amplifier matches the preset voltage;

[0013] An amplifier branch including the amplifier is connected to the reference branch via the switch branch, and an output voltage of the amplifier is obtained according to the second preset excitation signal in the second stage.

[0014] Further, the switch branch includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch and a seventh switch, wherein:

[0015] One end of the first switch is used to receive the reference voltage.

[0016] Furthermore, in the reference branch:

[0017] One end of the reference capacitor is grounded through the second switch;

[0018] One end of the reference capacitor is connected to the reference voltage through the third switch;

[0019] The other end of the reference capacitor is connected to the other end of the first switch;

[0020] The other end of the reference capacitor is grounded through the fourth switch and the fifth switch in sequence, one end of the capacitor to be measured is grounded, and the other end of the capacitor to be measured is connected to the connection point between the fourth switch and the fifth switch.

[0021] Furthermore, the amplifier branch also includes an adjustable capacitor, wherein:

[0022] The first input terminal of the amplifier is connected to the other end of the capacitor to be measured through the seventh switch;

[0023] The second input terminal of the amplifier is connected to the reference voltage;

[0024] The first input end of the amplifier is connected to the output end of the amplifier through the adjustable capacitor, and the first input end of the amplifier is connected to the output end of the amplifier through the sixth switch.

[0025] Furthermore, the size of the adjustable capacitor is determined by a preset detection range of the capacitor to be measured.

[0026] Furthermore, the signal input module includes a voltage source.

[0027] Furthermore, the first preset excitation signal and the second preset excitation signal have the same signal period.

[0028] In a second aspect, an embodiment of the present invention provides a chip, comprising a capacitance detection circuit as provided in the first aspect.

[0029] In a third aspect, an embodiment of the present invention provides a chip, including a capacitance detection circuit as provided in the first aspect, or a chip as provided in the second aspect.

[0030] A capacitance detection circuit, chip and electronic device proposed in an embodiment of the present invention can be divided into a first stage and a second stage when performing capacitance detection. The signal input module provides a reference voltage and a first preset excitation signal in the first stage. When the detection module receives the first preset excitation signal in the first stage, it gradually adjusts the capacitance of the reference capacitor until the voltage output by the amplifier matches the preset voltage. The control module collects the capacitance of the reference capacitor and the output voltage of the amplifier at this time as a fixed capacitance and a voltage deviation value respectively; the signal input module provides a reference voltage and a second preset excitation signal in the second stage, and records the output voltage of the amplifier in the second stage. The control module collects the output voltage and calculates the final capacitance of the capacitor to be tested by combining the fixed capacitance, voltage deviation value and reference voltage collected in the first stage. Since a voltage source is provided as an excitation signal in the present invention, the large error caused by the introduction of multiple excitation sources in the detection process is reduced, and the accuracy of capacitance detection is improved; and the fixed capacitance of the capacitor to be tested is obtained by time-division multiplexing the same detection module, which simplifies the test circuit and the corresponding test process, and improves the efficiency of inductive capacitance detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure of a capacitance detection circuit provided by an embodiment of the present invention;

[0032] Figure 2 A circuit diagram of a detection module provided by an embodiment of the present invention;

[0033] Figure 3 A schematic diagram of a first preset excitation signal and a second preset excitation signal provided in an embodiment of the present invention;

[0034] Figure 4 A schematic diagram of the structure of a chip provided by an embodiment of the present invention;

[0035] Figure 5 A schematic structural diagram of an electronic device provided by an embodiment of the present invention.

[0036] Reference numerals:

[0037] 100, capacitance detection circuit; 200, chip;

[0038] 300, electronic equipment; 110, signal input module;

[0039] 120, a detection module; 130, a control module.

[0040] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0041] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0042] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0043] In the embodiments of the present application, at least one refers to one or more; multiple refers to two or more. In the description of the present application, words such as "first", "second", "third", etc. are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0044] References to "one embodiment" or "some embodiments" etc. described in this specification mean that one or more embodiments of the present application include a particular feature, structure or characteristic described in conjunction with the embodiment. Thus, in this specification, the terms "include", "comprises", "has" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0045] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0046] Figure 1 A schematic diagram of a capacitance detection circuit 100 provided in an embodiment of the present invention is shown in FIG. Figure 1 As shown, the capacitance detection circuit 100 includes:

[0047] A signal input module 110, configured to provide a reference voltage, a first preset excitation signal, and a second preset excitation signal, wherein the reference voltage is provided by a voltage source;

[0048] A detection module 120 including a reference capacitor and an amplifier, configured to gradually adjust the capacitance of the reference capacitor according to the first preset excitation signal in a first stage until the voltage output by the amplifier matches the preset voltage, and to obtain the output voltage of the amplifier according to the second preset excitation signal in a second stage;

[0049] The control module 130 is used to collect the capacitance of the reference capacitor and the output voltage of the amplifier in the first stage to obtain the voltage deviation value and the fixed capacitance of the capacitor to be measured, and calculate the final capacitance of the capacitor to be measured according to the output voltage, the fixed capacitance, the voltage deviation value and the reference voltage in the second stage.

[0050] An embodiment of the present invention provides a capacitance detection circuit 100, which includes a signal input module 110, a detection module 120 and a control module 130, wherein a first end of the control module 130 is connected to one end of the signal input module 110, a second end of the control module 130 is connected to one end of the detection module 120, and the other end of the signal input module 110 is connected to the other end of the detection module 120.

[0051] During the operation of the capacitance detection circuit 100, the signal input module 110 first provides a reference voltage and a first preset excitation signal in the first stage. The reference voltage is preset, and the first preset excitation signal is a periodic pulse signal. The pulse amplitude and pulse width can be determined according to actual conditions, and the embodiment of the present invention does not make specific limitations on this.

[0052] For example, the signal input module 110 includes a voltage source, which is used to output a reference voltage. For example, when preparing to perform capacitance detection, the voltage source in the signal input module 110 is closed, thereby outputting a reference voltage; in addition, the signal input module 110 also provides a first preset excitation signal in the first stage, and the signal input module 110 may include a pulse generator, which outputs the first preset excitation signal.

[0053] After receiving the first preset excitation signal in the first stage, the detection module 120 gradually adjusts the capacitance of the reference capacitor, and can gradually adjust the reference capacitor according to the preset interval until the voltage output by the amplifier matches the preset voltage, and records the capacitance of the reference capacitor and the output voltage of the amplifier at this time. The control module 130 collects the capacitance of the reference capacitor in the first stage, uses the capacitance of the reference capacitor as the fixed capacitance of the capacitor to be measured, and uses the output voltage of the amplifier as the voltage deviation value.

[0054] The voltage output by the amplifier matches the preset voltage, which means that the difference between the voltage output by the amplifier and the preset voltage is within a preset difference range. For example, the preset voltage is VDD / 2, and VDD is the power supply of the entire capacitance detection circuit 100.

[0055] It should be noted that the capacitor to be measured can be decomposed into two parts. One part is the fixed capacitance, which refers to the inherent capacitance and does not change with external influences. It can also be understood as the value when the capacitance does not change; the other part is the variable capacitance introduced by changes in external conditions.

[0056] The embodiment of the present invention is divided into two stages. In the first stage, the fixed capacitance of the capacitor to be measured is first detected. In the process of finding the fixed capacitance, there is a certain error due to the accuracy problem caused by digital control. The voltage deviation value corresponds to the error value introduced in the process of finding the fixed capacitance. The second stage detects the final capacitance of the capacitor to be measured, that is, the capacitance after the change.

[0057] In the second stage, the capacitance detection circuit 100 is restarted, the signal input module 110 outputs a second preset excitation signal, and records the output voltage of the amplifier in real time. After the control module 130 collects the output voltage of the amplifier, it calculates the final capacitance of the capacitor to be measured based on the fixed capacitance, voltage deviation value and reference voltage collected in the first stage.

[0058] In the prior art, since there are generally multiple excitation sources, and the excitation sources are not ideal and there are matching errors, a large error will be generated when measuring capacitance; in this embodiment, the reference voltage is provided by only one voltage source, which can reduce the error caused by the excitation source, thereby improving the accuracy of capacitance measurement. The present invention introduces a single reference voltage signal source, and the capacitance detection output corresponds to the capacitance change between two detections. Since the two detections use the same voltage source, the introduced error is the same, so the detection accuracy of the change is relatively high, thereby improving the accuracy of capacitance detection.

[0059] A capacitance detection circuit 100 proposed in an embodiment of the present invention can be divided into a first stage and a second stage when performing capacitance detection. The signal input module 110 provides a reference voltage and a first preset excitation signal in the first stage. When the detection module 120 receives the first preset excitation signal in the first stage, it gradually adjusts the capacitance of the reference capacitor until the voltage output by the amplifier matches the preset voltage. The control module 130 collects the capacitance of the reference capacitor and the output voltage of the amplifier at this time as a fixed capacitance and a voltage deviation value, respectively; the signal input module 110 provides a reference voltage and a second preset excitation signal in the second stage, and records the output voltage of the amplifier in the second stage. The control module 130 collects the output voltage and calculates the final capacitance of the capacitor to be tested by combining the fixed capacitance, voltage deviation value and reference voltage collected in the first stage. Since a voltage source is provided as an excitation signal in the present invention, the large error caused by the introduction of multiple excitation sources in the detection process is reduced, and the accuracy of capacitance detection is improved; and the fixed capacitance of the capacitor to be tested is obtained by time-division multiplexing the same detection module 120, which simplifies the test circuit and the corresponding test process, and improves the efficiency of inductive capacitance detection.

[0060] In some embodiments, the detection module 120 includes:

[0061] a switch branch, configured to present a first switch state according to the first preset excitation signal, and present a second switch state according to the second preset excitation signal;

[0062] A reference branch comprising the reference capacitor, configured to gradually adjust the capacitance of the reference capacitor in the first switching state until the voltage output by the amplifier matches the preset voltage;

[0063] An amplifier branch including the amplifier is connected to the reference branch via the switch branch, and an output voltage of the amplifier is obtained according to the second preset excitation signal in the second stage.

[0064] An embodiment of the present invention provides a detection module 120, which includes a switch branch, a reference branch and an amplifier branch. The reference branch is connected to the amplifier branch through the switch branch. The switch branch presents different switching states under different excitation signals, so that the operation processes of the reference branch and the amplifier branch in different switching states are different.

[0065] In this embodiment, the switch branch presents a first switch state under the action of the first preset excitation signal, and presents a second switch state under the action of the second preset excitation signal. In the first switch state, the reference circuit gradually adjusts the capacitance of the reference capacitor until the voltage output by the amplifier matches the preset voltage, and collects the capacitance of the reference capacitor at this time through the control module 130, and uses the capacitance of the reference capacitor as the fixed capacitance of the capacitor to be measured, and also collects the output voltage of the amplifier at this time, and uses the output voltage as the voltage deviation value.

[0066] The amplifier branch is restarted in the second stage, and according to the second preset excitation signal, the capacitance of the reference capacitor will no longer be changed in the second stage. However, due to changes in external conditions, the capacitance of the capacitor to be measured will change. The change in the capacitance of the capacitor to be measured will cause the output voltage value of the amplifier to change. Therefore, the control module 130 records the output voltage of the amplifier at this time.

[0067] The present invention accurately finds the fixed capacitance of the capacitor to be measured by adjusting the value of the on-chip reference capacitance, records the voltage value output by the amplifier during the process of finding the fixed capacitance, and uses the voltage value as the voltage deviation value in the capacitance detection process, so as to facilitate the processing of subsequent algorithm links.

[0068] As an example, the first switch branch includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch and a seventh switch, wherein:

[0069] One end of the first switch is used to receive the reference voltage.

[0070] As an example, in the reference branch:

[0071] One end of the reference capacitor is grounded through the second switch;

[0072] One end of the reference capacitor is connected to the reference voltage through the third switch;

[0073] The other end of the reference capacitor is connected to the other end of the first switch;

[0074] The other end of the reference capacitor is grounded through the fourth switch and the fifth switch in sequence, one end of the capacitor to be measured is grounded, and the other end of the capacitor to be measured is connected to the connection point between the fourth switch and the fifth switch.

[0075] As an example, the amplifier branch further includes an adjustable capacitor, wherein:

[0076] The first input terminal of the amplifier is connected to the other end of the capacitor to be measured through the seventh switch;

[0077] The second input terminal of the amplifier is connected to the reference voltage;

[0078] The first input end of the amplifier is connected to the output end of the amplifier through the adjustable capacitor, and the first input end of the amplifier is connected to the output end of the amplifier through the sixth switch.

[0079] Figure 2 A circuit diagram of a detection module 120 provided in an embodiment of the present invention, Figure 3 A schematic diagram of a first preset excitation signal and a second preset excitation signal provided in an embodiment of the present invention, such as Figure 2 and Figure 3 As shown, the switch branch includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch and a seventh switch. Figure 2 In the figure, S1 to S7 are used to represent them respectively, Vref represents the terminal of the reference voltage, Ct represents the capacitor to be measured, Cb represents the reference capacitor, Cfb represents the adjustable capacitor, the first preset excitation signal is represented by CLK1, the second preset excitation signal is represented by CLK2, the amplifier is an operational amplifier, represented by OP, and this embodiment is described by taking the example of the switch closing after receiving a high level.

[0080] Among them, in the first stage, when the first preset excitation signal is at a high level, the first switch and the second switch are closed, the third switch is opened, and the reference capacitor is charged to the reference voltage; the fourth switch and the seventh switch are both opened, the fifth switch is closed, and the upper plate of the capacitor to be measured is discharged to a low level. In the first stage, when the first preset excitation signal is at a low level, the sixth switch is closed, the seventh switch is opened, the amplifier is in a reset state of unity gain, and its output voltage is equal to the reference voltage.

[0081] Phase 1: Start the capacitance detection circuit 100. At this time, the difference between the capacitance to be measured and the fixed capacitance is large, and the output value of the amplifier is large or saturated. The on-chip reference capacitance value can be gradually changed by binary search. For example, the step adjustment step is reduced by increasing the adjustment bit until the output voltage of the amplifier approaches VDD / 2. At this time, the corresponding voltage value is recorded as the voltage deviation value for subsequent algorithm processing.

[0082] In the second stage, when the second preset excitation signal is at a high level, the first switch and the second switch are disconnected, the third switch is closed, the lower plate voltage of the reference capacitor gradually increases from 0 to the reference voltage, the fifth switch and the sixth switch are disconnected, and the fourth switch and the seventh switch are closed. At this time, the charge on the reference capacitor will be transferred to the capacitor to be measured. Due to the different capacitance values ​​of the two, a voltage difference will be generated. The voltage difference is output through the amplifier, thereby realizing the detection of the change in the capacitance value of the capacitor to be measured.

[0083] The voltage difference formula generated by the charge transfer on the capacitor is:

[0084] △v=Vref(Ct-Cbase) / Cfb, where Ct is the final capacitance of the capacitor to be measured, Cbase is the fixed capacitance of the capacitor to be measured, Vref is the reference voltage, and △v is the output voltage of the second stage amplifier minus the voltage deviation value.

[0085] The operational amplifier used in this embodiment follows the control timing of the non-overlapping clock. During the reference capacitor charge sampling phase, the sixth switch connected across the amplifier is closed to put it in a reset state of unity gain. During the charge transfer and amplification period, the sixth switch is opened, and the amplifier outputs the voltage difference caused by the capacitance difference.

[0086] As an implementation manner, the capacitance range of the adjustable capacitor is determined by a preset detection range of the capacitor to be measured.

[0087] The formula for the voltage difference generated by the charge transfer on the capacitor to be measured is: △v=Vref(Ct-Cbase) / Cfb. From the formula, it can be seen that when Cfb increases, the capacitance change of Ct-Cbase can increase. Otherwise, the output end of the amplifier in the detection circuit is prone to saturation. Therefore, the size of the adjustable capacitor corresponds to the range of the capacitor to be measured. When the capacitor to be measured is determined to be in the preset detection range, the capacitance range of the adjustable capacitor can be determined based on the corresponding relationship.

[0088] In this embodiment, the size of the Cfb capacitor is adjusted to change the corresponding detection range of the capacitance to be measured according to different application environments, thereby being able to meet the capacitance change detection requirements of various application scenarios.

[0089] Figure 4 A schematic diagram of the structure of a chip 200 provided in an embodiment of the present invention is shown in FIG. Figure 4 As shown, the chip 200 includes the capacitance detection circuit 100 mentioned above.

[0090] The chip 200 (Integrated Circuit, IC) can be, but is not limited to, a system on chip (System on Chip, SOC) chip or a system in package (System in Package, SIP) chip. Since the chip 200 of the embodiment of the present invention includes the above-mentioned capacitance detection circuit 100, it can include all the beneficial effects of the above-mentioned capacitance detection circuit 100, and the embodiment of the present invention will not be repeated here.

[0091] Figure 5 A schematic diagram of the structure of an electronic device 300 provided in an embodiment of the present invention is shown in FIG. Figure 5 As shown, the electronic device 300 includes the above chip 200 , or the above capacitance detection circuit 100 .

[0092] Among them, the electronic device 300 can be but is not limited to a weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a human body composition analyzer, a mobile power supply, a wireless charger, a fast charger, a car charger, an adapter, a display, a Universal Serial Bus (USB) docking station, a stylus, a true wireless headset, a car central control screen, a car, a smart wearable device, a mobile terminal, and a smart home device. Smart wearable devices include but are not limited to smart watches, smart bracelets, and cervical massagers. Mobile terminals include but are not limited to smart phones, laptops, tablets, and point of sales terminals (POS). Smart home devices include but are not limited to smart sockets, smart rice cookers, smart sweepers, and smart lights.

[0093] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0094] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A capacitance detection circuit, characterized in that: include: A signal input module, used for providing a reference voltage, a first preset excitation signal and a second preset excitation signal, wherein the reference voltage is provided by a voltage source; A detection module including a reference capacitor and an amplifier, configured to gradually adjust the capacitance of the reference capacitor according to the first preset excitation signal in a first stage until the voltage output by the amplifier matches the preset voltage, and to obtain the output voltage of the amplifier according to the second preset excitation signal in a second stage; The control module is used to collect the capacitance of the reference capacitor and the output voltage of the amplifier in the first stage to obtain the voltage deviation value and the fixed capacitance of the capacitor to be measured, and calculate the final capacitance of the capacitor to be measured according to the output voltage, the fixed capacitance, the voltage deviation value and the reference voltage in the second stage.

2. The capacitance detection circuit according to claim 1, characterized in that: The detection module comprises: a switch branch, configured to present a first switch state according to the first preset excitation signal, and present a second switch state according to the second preset excitation signal; A reference branch comprising the reference capacitor, configured to gradually adjust the capacitance of the reference capacitor in the first switching state until the voltage output by the amplifier matches the preset voltage; An amplifier branch including the amplifier is connected to the reference branch via the switch branch, and an output voltage of the amplifier is obtained according to the second preset excitation signal in the second stage.

3. The capacitance detection circuit according to claim 2, characterized in that: The switch branch includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch and a seventh switch, wherein: One end of the first switch is used to receive the reference voltage.

4. The capacitance detection circuit according to claim 3, characterized in that: In the reference branch: One end of the reference capacitor is grounded through the second switch; One end of the reference capacitor is connected to the reference voltage through the third switch; The other end of the reference capacitor is connected to the other end of the first switch; The other end of the reference capacitor is grounded through the fourth switch and the fifth switch in sequence, one end of the capacitor to be measured is grounded, and the other end of the capacitor to be measured is connected to the connection point between the fourth switch and the fifth switch.

5. The capacitance detection circuit according to claim 3, characterized in that: The amplifier branch also includes an adjustable capacitor, wherein: The first input terminal of the amplifier is connected to the other end of the capacitor to be measured through the seventh switch; The second input terminal of the amplifier is connected to the reference voltage; The first input end of the amplifier is connected to the output end of the amplifier through the adjustable capacitor, and the first input end of the amplifier is connected to the output end of the amplifier through the sixth switch.

6. The capacitance detection circuit according to claim 5, characterized in that: The size of the adjustable capacitor is determined by a preset detection range of the capacitor to be measured.

7. The capacitance detection circuit according to any one of claims 1 to 6, characterized in that: The signal input module includes a voltage source.

8. The capacitance detection circuit according to claim 1, characterized in that: The first preset excitation signal and the second preset excitation signal have the same signal period.

9. A chip, characterized in that: The method comprises a capacitance detection circuit as claimed in any one of claims 1 to 8.

10. An electronic device, characterized in that: It comprises the capacitance detection circuit as described in any one of claims 1 to 8, or the chip as described in claim 9.

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