Sensing circuit and sensing method of capacitive pressure sensing array

Abstract

The present application discloses a sensing circuit and a sensing method of a capacitive pressure sensor array, which belongs to the field of capacitive pressure sensing. The sensing circuit alternately inputs a positive excitation voltage and a negative excitation voltage at the positive input terminal of an operational amplifier, or alternately inputs a positive excitation voltage and a negative excitation voltage at the driving end of a pressure sensing capacitor, and the inverting input terminal of the operational amplifier is connected to the detection terminal of the pressure sensing capacitor of the corresponding column, so as to obtain a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage outputted from the output terminal of the operational amplifier, respectively, so as to calculate the capacitance value of the pressure sensing capacitor of the target row based on the amplitude of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor. The present application can improve the detection accuracy of the sensing capacitance of the capacitive pressure sensor array and meet the demand for high-precision pressure distribution measurement.

Description

Technical Field

[0001] The present application relates to the field of capacitive pressure sensing technology, and in particular, to a sensing circuit of a capacitive pressure sensing array and a sensing method thereof. Background Art

[0002] A capacitive pressure sensor is a pressure sensor that uses a capacitive sensitive element to convert the measured pressure into an electrical output that is in a certain relationship with the pressure. Compared with resistive pressure sensors, capacitive pressure sensors generally have higher sensitivity and lower detection limits. With the research and development of ionic conductive materials, ionic capacitive pressure sensors based on ionic conductive materials have emerged in the industry. This type of capacitive pressure sensor has the advantages of good flexibility, high sensitivity, low power consumption, and low temperature dependence. It can constitute a capacitive pressure sensor array for high-precision pressure distribution measurement in different fields such as consumer electronics, smart wearables, medical devices, and industrial testing. However, the poor linear response of these capacitive pressure sensor arrays and their sensitivity to parasitic capacitance and edge capacitance reduce the detection accuracy of conventional capacitive sensing circuits based on capacitive pressure sensor arrays for sensing capacitance, thereby failing to meet the needs of high-precision pressure distribution measurement. Therefore, there is an urgent need for an improved sensing circuit and sensing method for a capacitive pressure sensor array to solve the above technical problems. Summary of the invention

[0003] In view of this, the present application proposes a sensing circuit of a capacitive pressure sensor array and a sensing method thereof, which can improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for sensing capacitance and meet the needs of high-precision pressure distribution measurement in different application scenarios such as medical devices.

[0004] In a first aspect, an embodiment of the present application provides a sensing circuit of a capacitive pressure sensing array, comprising:

[0005] A capacitive pressure sensing array, comprising m rows and n columns of pressure sensing capacitors, a reference voltage is input to a driving end of the pressure sensing capacitor, and m and n are integers greater than or equal to 1;

[0006] At least one capacitance-pressure conversion unit, each capacitance-pressure conversion unit includes an operational amplifier and a reference capacitor, two ends of the reference capacitor are respectively connected to the inverting input terminal and the output terminal of the operational amplifier, the inverting input terminal of the operational amplifier is connected to the detection terminal of the pressure sensing capacitor of the corresponding column among the m rows and n columns of pressure sensing capacitors; the non-inverting input terminal of the operational amplifier is configured to alternately input a positive excitation voltage and a negative excitation voltage, and the output terminal of the operational amplifier outputs a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively;

[0007] A control unit is connected to the output end of the operational amplifier and is used to calculate the capacitance value of the pressure sensing capacitor of the target row among the m rows and n columns of pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

[0008] In some embodiments, the non-phase input terminal of the operational amplifier is configured to alternately input a positive excitation voltage and a negative excitation voltage, including: the non-phase input terminal of the operational amplifier sequentially inputs a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude, or the non-phase input terminal of the operational amplifier sequentially inputs a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

[0009] In some implementations, the calculating the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0010] The ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0011] In some implementations, the calculating the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0012] The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0013] In some implementations, the non-inverting input terminal of the operational amplifier is configured to input a reference voltage before inputting a positive excitation voltage and a negative excitation voltage to clear charges of the pressure sensing capacitor and the reference capacitor of the target row.

[0014] In some implementations, the reference voltage is input to a driving end of the pressure sensing capacitor through at least one gate switch.

[0015] In some embodiments, the sensing circuit further includes a multi-way selection unit, and the multi-way selection unit is used to sequentially connect the detection ends of at least one column of pressure sensing capacitors to the inverting input end of the operational amplifier.

[0016] In some embodiments, the capacitive pressure sensing array includes an ionic thin film dielectric layer and an electrode array layer, and the m-row and n-column pressure sensing capacitors are formed by the ionic thin film dielectric layer and the electrode array layer.

[0017] In a second aspect, the present application also provides a sensing circuit of a capacitive pressure sensing array, including:

[0018] A capacitive pressure sensing array, comprising m rows and n columns of pressure sensing capacitors, wherein a driving end of the pressure sensing capacitor is configured to alternately input a positive excitation voltage and a negative excitation voltage, and m and n are integers greater than or equal to 1;

[0019] At least one capacitance-pressure conversion unit, each capacitance-pressure conversion unit includes an operational amplifier and a reference capacitor, two ends of the reference capacitor are respectively connected to the inverting input terminal and the output terminal of the operational amplifier, the inverting input terminal of the operational amplifier is connected to the detection terminal of the pressure sensing capacitor of the corresponding column among the m rows and n columns of pressure sensing capacitors; the positive input terminal of the operational amplifier inputs a reference voltage, and the output terminal of the operational amplifier outputs a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively;

[0020] A control unit is connected to the output end of the operational amplifier and is used to calculate the capacitance value of the pressure sensing capacitor of the target row among the m rows and n columns of pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

[0021] In some embodiments, the driving end of the pressure sensing capacitor is configured to alternately input a positive excitation voltage and a negative excitation voltage, including: the driving end of the pressure sensing capacitor sequentially inputs a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude, or the driving end of the pressure sensing capacitor sequentially inputs a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

[0022] In some implementations, the calculating the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0023] The ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0024] In some implementations, the calculating the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0025] The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0026] In some implementations, the driving end of the pressure sensing capacitor is configured to input a reference voltage before inputting a positive excitation voltage and a negative excitation voltage to clear the charges of the pressure sensing capacitor and the reference capacitor of the target row.

[0027] In some implementations, the positive excitation voltage and the negative excitation voltage are input to the driving end of the pressure sensing capacitor through at least one gate switch.

[0028] In some embodiments, the sensing circuit further includes a multi-way selection unit, and the multi-way selection unit is used to sequentially connect the detection ends of at least one column of pressure sensing capacitors to the inverting input end of the operational amplifier.

[0029] In some embodiments, the capacitive pressure sensing array includes an ionic thin film dielectric layer and an electrode array layer, and the m-row and n-column pressure sensing capacitors are formed by the ionic thin film dielectric layer and the electrode array layer.

[0030] In a third aspect, an embodiment of the present application further provides a sensing method of a capacitive pressure sensing array, which is applied to the sensing circuit of the capacitive pressure sensing array described in the first aspect, comprising:

[0031] Alternately inputting a positive excitation voltage and a negative excitation voltage into the non-phase input terminal of the operational amplifier, so as to detect a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively, from the output terminal of the operational amplifier;

[0032] The capacitance value of the pressure sensing capacitor of the target row is calculated based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

[0033] In some implementations, alternately inputting a positive excitation voltage and a negative excitation voltage to the non-inverting input terminal of the operational amplifier comprises:

[0034] A positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude are sequentially input to the non-inverting input terminal of the operational amplifier, or a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude are sequentially input to the non-inverting input terminal of the operational amplifier.

[0035] In some implementations, the step of calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0036] The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0037] In some embodiments, the method includes: before inputting a positive excitation voltage and a negative excitation voltage to the positive input terminal of the operational amplifier, inputting a reference voltage to the positive input terminal of the operational amplifier to clear the charge of the pressure sensing capacitor and the reference capacitor of the target row.

[0038] In a fourth aspect, an embodiment of the present application further provides a sensing method of a capacitive pressure sensing array, which is applied to a sensing circuit of the capacitive pressure sensing array described in the second aspect, comprising:

[0039] Alternately inputting a positive excitation voltage and a negative excitation voltage to the driving end of the pressure sensing capacitor of the target row, so as to detect a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively, from the output end of the operational amplifier;

[0040] The capacitance value of the pressure sensing capacitor of the target row is calculated based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

[0041] In some implementations, alternately inputting a positive excitation voltage and a negative excitation voltage to a driving end of the pressure sensing capacitor of the target row includes:

[0042] A positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude are sequentially input to the driving end of the pressure sensing capacitor of the target row, or a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude are sequentially input to the driving end of the pressure sensing capacitor of the target row.

[0043] In some implementations, the step of calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0044] The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0045] In some embodiments, the method includes: before inputting a positive excitation voltage and a negative excitation voltage to the driving end of the pressure sensing capacitor of the target row, inputting a reference voltage to the driving end of the pressure sensing capacitor of the target row to clear the charge of the pressure sensing capacitor and the reference capacitor of the target row.

[0046] The embodiments of the present application can at least achieve the following beneficial effects:

[0047] The embodiments of the present application input a reference voltage at the driving end of the pressure sensing capacitor, alternately input a positive excitation voltage and a negative excitation voltage at the non-phase input end of the operational amplifier, or alternately input a positive excitation voltage and a negative excitation voltage at the driving end of the pressure sensing capacitor, input a reference voltage at the non-phase input end of the operational amplifier, and connect the inverting input end of the operational amplifier to the detection end of the pressure sensing capacitor of the corresponding column, so as to obtain a first detection voltage and a second detection voltage respectively corresponding to the positive excitation voltage and the negative excitation voltage outputted from the output end of the operational amplifier, so that the control unit can quickly calculate the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor, which can significantly improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor and meet the needs of high-precision pressure distribution measurement in different application scenarios such as medical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope of the present application.

[0049] Figure 1 is a schematic diagram of the circuit structure of a sensing circuit of a capacitive pressure sensing array according to the first embodiment of the present application;

[0050] Figure 2 is a schematic diagram of the principle of a capacity-voltage conversion unit in a sensing circuit according to the first embodiment of the present application;

[0051] Figure 3 is a schematic diagram of the circuit structure of a sensing circuit of a capacitive pressure sensing array according to a second embodiment of the present application;

[0052] Figure 4 is a schematic diagram of a circuit structure of a sensing circuit of a capacitive pressure sensing array according to a third embodiment of the present application;

[0053] Figure 5 is a schematic diagram of the principle of a capacity-voltage conversion unit in a sensing circuit according to a third embodiment of the present application;

[0054] Figure 6 is a schematic diagram of an alternative structure of a reference capacitor in a sensing circuit according to any embodiment of the present application;

[0055] Figure 7 is a flow chart of a sensing method of a capacitive pressure sensing array according to the first embodiment of the present application;

[0056] Figure 8 4 is a flow chart of a sensing method of a capacitive pressure sensing array according to a second embodiment of the present application. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the drawings of the embodiment of the present application. However, it should be understood that the described embodiments are only some exemplary embodiments of the present application, rather than all embodiments, and therefore the following detailed description of the embodiment of the present application is not intended to limit the scope of the present application for protection. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0058] It should be noted that the terms "first", "second", etc. in the specification and claims of this application are only used to distinguish and describe similar objects, rather than to describe a specific order or sequence, and cannot be understood as indicating or implying relative importance.

[0059] As mentioned above, capacitive pressure sensing arrays including ionic capacitive pressure sensors have poor linear response and sensitivity to parasitic capacitance and edge capacitance, which reduces the detection accuracy of conventional capacitive sensing circuits based on capacitive pressure sensor arrays for sensing capacitance, and thus cannot meet the needs of high-precision pressure distribution measurement. To this end, the present application proposes a sensing circuit of a capacitive pressure sensing array and a sensing method thereof, which can improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for sensing capacitance and meet the needs of high-precision pressure distribution measurement.

[0060] Figure 1FIG. 1 is a schematic diagram of the circuit structure of the sensing circuit 100 of the capacitive pressure sensing array according to the first embodiment of the present application. Figure 1 As shown, the sensing circuit 100 of the capacitive pressure sensing array of this embodiment includes:

[0061] The capacitive pressure sensing array 110 includes m rows and n columns of pressure sensing capacitors, wherein a reference voltage is input to a driving end of the pressure sensing capacitor, and m and n are integers greater than or equal to 1. The m rows and n columns of pressure sensing capacitors can be represented by the first row C11-C1n, the second row C21-C2n, ..., the mth row Cm1-Cmn according to rows; and can be represented by the first column C11-Cm1, the second column C12-Cm2, ..., the nth column C1n-Cmn according to columns;

[0062] At least one capacitance-pressure conversion unit 120, each capacitance-pressure conversion unit 120 includes an operational amplifier (OA1-OAn) and a reference capacitor (Cr1-Crn), two ends of the reference capacitor (Cr1-Crn) are respectively connected to the inverting input terminal and the output terminal of the operational amplifier (OA1-OAn), the inverting input terminal of the operational amplifier (OA1-OAn) is connected to the detection terminal of the pressure sensing capacitor of the corresponding column among the m rows and n columns of the pressure sensing capacitor; the non-inverting input terminal of the operational amplifier (OA1-OAn) is configured to alternately input a positive excitation voltage and a negative excitation voltage, and the output terminal of the operational amplifier (OA1-OAn) outputs a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively;

[0063] The control unit 130 is connected to the output end of the operational amplifier (OA1-OAn) and is used to calculate the capacitance value of the pressure sensing capacitor of the target row among the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor (Cr1-Crn).

[0064] In this embodiment, the capacitive pressure sensing array 110 may include a sensing array composed of any type of capacitive pressure sensors. Preferably, in one embodiment, the capacitive pressure sensing array 110 may include a sensing array composed of ionic capacitive pressure sensors. When the capacitive pressure sensing array 110 is composed of ionic capacitive pressure sensors, the capacitive pressure sensing array 110 may include an ionic thin film dielectric layer and an electrode array layer, and the ionic thin film dielectric layer and the electrode array layer composed of m rows and n columns of electrodes together form the m rows and n columns of pressure sensing capacitors.

[0065] In this embodiment, each pressure sensing capacitor in each row of pressure sensing capacitors in the capacitive pressure sensing array 110 has a driving end and a detection end, wherein the driving end of each row of pressure sensing capacitors is connected to a driving voltage S0, which is a fixed reference voltage Vref. In one embodiment, the driving end of each row of pressure sensing capacitors inputs the reference voltage Vref through at least one selection switch (SW1-SWm).

[0066] In this embodiment, each capacitance-pressure conversion unit 120 includes an operational amplifier (OA1-OAn) and a reference capacitor (Cr1-Crn), the two ends of the reference capacitor (Cr1-Crn) are respectively connected to the inverting input and output ends of the operational amplifier (OA1-OAn), and the inverting input end of the operational amplifier (OA1-OAn) is connected to the detection end of the pressure sensing capacitor of the corresponding column among the m rows and n columns of pressure sensing capacitors. For example, for the capacitance-pressure conversion unit 120 composed of the operational amplifier OA1 and the reference capacitor Cr1, the inverting input terminal of the operational amplifier OA1 is connected to the detection terminal of the first column of pressure sensing capacitors C11-Cm1; for the capacitance-pressure conversion unit 120 composed of the operational amplifier OA2 and the reference capacitor Cr2, the inverting input terminal of the operational amplifier OA2 is connected to the detection terminal of the second column of pressure sensing capacitors C12-Cm2; and so on, for the capacitance-pressure conversion unit 120 composed of the operational amplifier OAn and the reference capacitor Crn, the inverting input terminal of the operational amplifier OAn is connected to the detection terminal of the nth column of pressure sensing capacitors C1n-Cmn.

[0067] In this embodiment, in each capacitance-pressure conversion unit 120, the non-phase input terminal of the operational amplifier (OA1-OAn) inputs the excitation voltage S1, and the excitation voltage S1 is configured to alternately input the positive excitation voltage and the negative excitation voltage. Accordingly, the output terminal of the operational amplifier (OA1-OAn) can output the first detection voltage and the second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively, and the first detection voltage and the second detection voltage can be detected by the control unit 130 connected to the output terminal of the operational amplifier (OA1-OAn). The control unit 130 can calculate the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitor based on the amplitude of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor (Cr1-Crn). The target row here refers to the current selected row in the m-row and n-column pressure sensing capacitor. At this time, the target row is in the selected state, and its driving end inputs the reference voltage Vref.

[0068] In some embodiments, the control unit 130 may include analog-to-digital conversion (ADC) channels of a number corresponding to the number of columns n of the m-row and n-column pressure sensing capacitors, and the output terminals of the operational amplifiers (OA1-OAn) corresponding to each column are respectively connected to the corresponding analog-to-digital conversion (ADC) channels. Under the combined effect of the excitation voltage S1 input to the non-inverting input terminal of the operational amplifier (OA1-OAn) and the driving voltage S0 (i.e., the reference voltage Vref) input to the driving terminal of the pressure sensing capacitor of the target row, the first detection voltage and the second detection voltage output from the output terminal of the operational amplifier (OA1-OAn) are input to the analog-to-digital conversion (ADC) channel corresponding to the control unit 130, and the capacitance value of each pressure sensing capacitor of the target row is calculated after analog-to-digital conversion.

[0069] In this embodiment, the control unit 130 can calculate the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor. In one implementation, the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors calculated based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0070] The ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0071] The calculation principle of the sensing capacitance calculation formula can be combined with Figure 2 It is derived by the following formula:

[0072] like Figure 2 As shown, taking the capacitance-pressure conversion unit 120 corresponding to the first column as an example, according to the virtual short principle of the operational amplifier, when the excitation voltage S1 input to the positive input terminal of the operational amplifier OA1 is changed, the voltage across the pressure sensing capacitor C11 changes and charge transfer occurs. Since the leakage of each pin of the operational amplifier OA1 is very small, the charge amount of the pressure sensing capacitor C11 is basically the same as the charge amount of the reference capacitor Cr1. Assume that the charge amount of the pressure sensing capacitor C11 is expressed as , the charge change of reference capacitor Cr1 is expressed as , then we can conclude .

[0073] Assume that the voltage change of the pressure sensing capacitor C11 is expressed as , the capacitance value of the pressure sensing capacitor C11 is expressed as , the voltage change of the reference capacitor Cr1 is expressed as , the capacitance value of the reference capacitor Cr1 is expressed as , then we can get:

[0074] .

[0075] Assuming that the reference voltage is represented by Vref, the amplitude of the forward excitation voltage input to the non-inverting input terminal of the operational amplifier OA1 is represented by , the amplitude of the negative excitation voltage is expressed as When the non-inverting input terminal of the operational amplifier OA1 first changes from the input reference voltage to the input forward excitation voltage for a predetermined time, the input voltage of the non-inverting input terminal of the operational amplifier OA1 changes from the reference voltage Vref to At this time, the first detection voltage corresponding to the forward excitation voltage at the output end of the operational amplifier OA1 is expressed as , then according to the above formula we can further get:

[0076] .

[0077] When the positive input terminal of the operational amplifier OA1 changes from the input reference voltage to the input negative excitation voltage for a predetermined time, the input voltage of the positive input terminal of the operational amplifier OA1 changes from the reference voltage Vref to At this time, the second detection voltage corresponding to the negative excitation voltage at the output terminal of the operational amplifier OA1 is expressed as , then according to the above formula we can further get:

[0078] .

[0079] Subtracting the above two formulas, we can further deduce:

[0080] ;

[0081] Thus, formula (1) can be obtained as follows:

[0082] (1).

[0083] Similarly, when the positive input terminal of the operational amplifier OA1 first changes from the input reference voltage to the input negative excitation voltage for a predetermined time, the input voltage of the positive input terminal of the operational amplifier OA1 changes from the reference voltage Vref to At this time, the second detection voltage corresponding to the negative excitation voltage at the output terminal of the operational amplifier OA1 is expressed as , then according to the above formula we can further get:

[0084] .

[0085] When the non-inverting input terminal of the operational amplifier OA1 changes from the input reference voltage to the input forward excitation voltage for a predetermined time, the input voltage of the non-inverting input terminal of the operational amplifier OA1 changes from the reference voltage Vref to At this time, the first detection voltage corresponding to the forward excitation voltage at the output end of the operational amplifier OA1 is expressed as , then according to the above formula we can further get:

[0086] .

[0087] Subtracting the above two formulas, we can also further deduce:

[0088] .

[0089] Therefore, the above formula (1) can also be obtained.

[0090] It can be seen that the capacitance value of the pressure sensing capacitor C11 is highly correlated with the ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage, and the capacitance value of the reference capacitor. Therefore, the control unit 130 can calculate the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the difference between the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

[0091] This pressure sensing capacitor sensing calculation method of the control unit 130 alternately inputs a positive excitation voltage and a negative excitation voltage into the non-phase input terminal of the operational amplifier. Based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the difference between the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor, the capacitance value of the pressure sensing capacitor of the target row can be quickly and accurately calculated. This can significantly improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor and meet the needs of high-precision pressure distribution measurement in different scenarios.

[0092] In summary, the sensing circuit of the embodiment of the present application inputs a reference voltage at the driving end of the pressure sensing capacitor, connects the inverting input end of the operational amplifier to the detection end of the pressure sensing capacitor of the corresponding column, and alternately inputs a positive excitation voltage and a negative excitation voltage at the non-phase input end of the operational amplifier to obtain a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage output from the output end of the operational amplifier, respectively. Therefore, the control unit can quickly calculate the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor, which can significantly improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor and meet the needs of high-precision pressure distribution measurement in different scenarios.

[0093] In some implementations, alternately inputting a positive excitation voltage and a negative excitation voltage to the non-inverting input terminal of the operational amplifier (OA1-OAn) comprises:

[0094] The positive excitation voltage and the negative excitation voltage with the same excitation time and the same amplitude are sequentially input to the non-inverting input terminal of the operational amplifier (OA1-OAn), or the negative excitation voltage and the positive excitation voltage with the same excitation time and the same amplitude are sequentially input to the non-inverting input terminal of the operational amplifier (OA1-OAn).

[0095] In this embodiment, the positive excitation voltage and the negative excitation voltage are symmetrical excitation voltages with the same excitation time, equal amplitude, and opposite polarity. By alternately inputting symmetrical excitation voltages with the same excitation time, equal amplitude, and opposite polarity to the positive phase input terminal of the operational amplifier (OA1-OAn), the order of inputting the positive excitation voltage and the negative excitation voltage can be arbitrarily exchanged, which can effectively avoid the polarization and electrolytic failure caused by the long-term DC deviation of the pressure sensing capacitor in the capacitive sensing array, especially in the application scenario of the capacitive pressure sensing array composed of ionic capacitive pressure sensors, which can significantly improve the service life and detection accuracy of the capacitive pressure sensing array 110.

[0096] In some implementations, the control unit 130 calculates the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor, which may further include:

[0097] The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0098] In this embodiment, according to the above formula, the control unit 130 can calculate the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitor based on the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage, the difference between the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor. Then, further, the sensing capacitance calculation formula can also be combined with Figure 2 Further deduction is as follows:

[0099] like Figure 2 As shown, it is assumed that the positive excitation voltage and negative excitation voltage input to the non-inverting input terminal of the operational amplifier OA1 are symmetrical excitation voltages with the same excitation time and equal amplitude. It is assumed that the amplitudes of the positive excitation voltage and the negative excitation voltage are expressed as When the non-inverting input terminal of the operational amplifier OA1 first changes from the input reference voltage to the input forward excitation voltage for a predetermined time, the input voltage of the non-inverting input terminal of the operational amplifier OA1 changes from the reference voltage Vref to At this point, according to the above formula, we can further obtain:

[0100] .

[0101] When the positive input terminal of the operational amplifier OA1 changes from the input reference voltage to the input negative excitation voltage for a predetermined time, the input voltage of the positive input terminal of the operational amplifier OA1 changes from the reference voltage Vref to At this point, according to the above formula, we can further obtain:

[0102] .

[0103] Subtracting the above two formulas, we can further deduce:

[0104] ;

[0105] Thus, we can get formula (2):

[0106] (2).

[0107] Similarly, when the non-inverting input terminal of the operational amplifier OA1 first changes from the input reference voltage to the negative excitation voltage input for a predetermined time, and then when the non-inverting input terminal of the operational amplifier OA1 changes from the input reference voltage to the positive excitation voltage input for a predetermined time, then according to the above formula, it can be further obtained that:

[0108] .

[0109] Subtracting the above two formulas, we can also further deduce the above formula (2). It can be seen that formula (2) is equivalent to replacing the amplitudes of the positive excitation voltage and the negative excitation voltage with the same amplitude in formula (1). And get.

[0110] Therefore, in this embodiment, the capacitance value of the pressure sensing capacitor C11 is highly correlated with the ratio of the difference between the first detection voltage and the second detection voltage to twice the amplitude of the positive excitation voltage and the negative excitation voltage, and the capacitance value of the reference capacitor. This embodiment is based on calculating the ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage, and based on the product of the ratio and the capacitance value of the reference capacitor to calculate the capacitance value of the pressure sensing capacitor. The sensing calculation method of the pressure sensing capacitor of the control unit 130 is to alternately input a symmetrical positive excitation voltage and a negative excitation voltage of equal amplitude into the non-phase input terminal of the operational amplifier. Based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the difference between the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor, the capacitance value of the pressure sensing capacitor of the target row can be quickly and accurately calculated. On the basis of any of the aforementioned implementation modes, the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor can be further significantly improved. At the same time, the service life of the capacitive pressure sensor array and its adaptability to different pressure sensing scenarios can also be improved, thereby meeting the needs of high-precision pressure distribution measurement in different scenarios.

[0111] In some implementations, the non-inverting input terminal of the operational amplifier (OA1-OAn) may be further configured to input a reference voltage before inputting a positive excitation voltage and a negative excitation voltage to clear the charge of the pressure sensing capacitor and the reference capacitor of the target row.

[0112] In this embodiment, in order to ensure the sensing accuracy of the pressure sensing capacitor of the target row and avoid being affected by the parasitic capacitance of the pressure sensing capacitor and the reference capacitor, before the positive excitation voltage and the negative excitation voltage are alternately input to the positive input terminal of the operational amplifier (OA1-OAn) each time, the reference voltage Vref can be input to the positive input terminal of the operational amplifier (OA1-OAn) to clear the charge of the pressure sensing capacitor and the reference capacitor, so that the pressure sensing capacitor of the target row and the reference capacitor in the corresponding column of the capacitive-pressure conversion unit 120 are in a state of charge clearing before each detection cycle of the capacitive-pressure conversion unit 120 starts. When the reference voltage Vref is input to the positive input terminal of the operational amplifier (OA1-OAn), since the driving end of each pressure sensing capacitor of the target row is also input with the reference voltage Vref, due to the voltage following effect of the operational amplifier (OA1-OAn) at this time, the voltages at both ends of the pressure sensing capacitor of the target row and the reference capacitor in the capacitive-pressure conversion unit 120 of the corresponding column are both at the reference voltage, which substantially causes the pressure sensing capacitor and the reference capacitor to be in a state of charge clearing.

[0113] Figure 3 FIG. 2 is a schematic diagram of the circuit structure of a sensing circuit 200 of a capacitive pressure sensing array according to a second embodiment of the present application. Figure 3 As shown, the sensing circuit 200 of the capacitive pressure sensing array of this embodiment, based on any of the aforementioned implementations, further includes: a multi-way selection unit 140, which is used to connect the detection ends of at least one column of pressure sensing capacitors to the inverting input end of at least one operational amplifier (OA1-OAa) in sequence.

[0114] In this embodiment, the number a of the capacitance-pressure conversion units 120 depends on the number a of the analog-to-digital conversion (ADC) channels of the control unit 130. When the number a of the analog-to-digital conversion (ADC) channels of the control unit 130 is less than the number n of columns of the m rows and n columns of pressure sensing capacitors, that is, it is insufficient to meet the detection requirements of the pressure sensing capacitors of all columns of the m rows and n columns of pressure sensing capacitors, the detection ends of the n columns of pressure sensing capacitors can be connected to the inverting input ends of the corresponding operational amplifiers (OA1-OAa) in a capacitance-pressure conversion units 120 in a sequentially selected manner through the multi-way selection unit 140.

[0115] For example, when the number of analog-to-digital conversion (ADC) channels of the control unit 130 is 1, the number of the capacitive-pressure conversion unit 120 is 1, and the one capacitive-pressure conversion unit 120 includes an operational amplifier (OA1). At this time, the multiplexer 140 can connect the detection ends of all n columns of pressure sensing capacitors to the inverting input end of the operational amplifier (OA1) of the capacitive-pressure conversion unit 120 in a sequentially selected manner; when the number of analog-to-digital conversion (ADC) channels of the control unit 130 is 2, the number of the capacitive-pressure conversion unit 120 is 2, and the two capacitive-pressure conversion units 120 include operational amplifiers (OA1, OA2). At this time, the multiplexer 140 can connect the detection ends of all n columns of pressure sensing capacitors to the inverting input end of the operational amplifier (OA1) of the capacitive-pressure conversion unit 120 in a sequentially selected manner. The detection ends of every two columns of pressure sensing capacitors in the pressure sensing capacitor are connected to the inverting input ends of the operational amplifiers (OA1, OA2) of the capacitive-pressure conversion unit 120 in a sequentially selected manner; similarly, by analogy, when the number of analog-to-digital conversion (ADC) channels of the control unit 130 is a, a is less than n, the number of the capacitive-pressure conversion units 120 is a, and the a capacitive-pressure conversion units 120 include operational amplifiers (OA1-OAa). At this time, the multiplexing unit 140 can connect the detection ends of each a column of pressure sensing capacitors in all n columns of pressure sensing capacitors to the inverting input ends of the operational amplifiers (OA1-OAa) of the capacitive-pressure conversion unit 120 in a sequentially selected manner.

[0116] It can be understood that when the number of analog-to-digital conversion (ADC) channels of the control unit 130 is n, the number of the capacitive-pressure conversion units 120 is n, and the n capacitive-pressure conversion units 120 include operational amplifiers (OA1-OAn). At this time, all the paths of the multi-way selection unit 140 are enabled, that is, the detection ends of all n columns of pressure sensing capacitors can be simultaneously connected to the inverting input ends of the operational amplifiers (OA1-OAn) of the n capacitive-pressure conversion units 120.

[0117] Figure 4 FIG. 3 is a schematic diagram of the circuit structure of a sensing circuit 300 of a capacitive pressure sensing array according to the third embodiment of the present application. Figure 4 As shown, the sensing circuit 300 of the capacitive pressure sensing array of this embodiment includes:

[0118] The capacitive pressure sensing array 110 includes m rows and n columns of pressure sensing capacitors, wherein the driving end of the pressure sensing capacitor is configured to alternately input a positive excitation voltage and a negative excitation voltage, wherein m and n are integers greater than or equal to 1, and the m rows and n columns of pressure sensing capacitors can be represented by the first row C11-C1n, the second row C21-C2n, ..., the mth row Cm1-Cmn according to the row; and can be represented by the first column C11-Cm1, the second column C12-Cm2, ..., the nth column C1n-Cmn according to the column;

[0119] At least one capacitance-pressure conversion unit 120, each capacitance-pressure conversion unit 120 includes an operational amplifier (OA1-OAn) and a reference capacitor (Cr1-Crn), two ends of the reference capacitor (Cr1-Crn) are respectively connected to the inverting input terminal and the output terminal of the operational amplifier (OA1-OAn), the inverting input terminal of the operational amplifier (OA1-OAn) is connected to the detection terminal of the pressure sensing capacitor of the corresponding column among the m rows and n columns of the pressure sensing capacitor; the positive input terminal of the operational amplifier (OA1-OAn) inputs a reference voltage, and the output terminal of the operational amplifier (OA1-OAn) outputs a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively;

[0120] The control unit 130 is connected to the output end of the operational amplifier (OA1-OAn) and is used to calculate the capacitance value of the pressure sensing capacitor of the target row among the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor (Cr1-Crn).

[0121] The difference between this embodiment and the aforementioned first embodiment is that the driving end of the pressure sensing capacitor no longer inputs a reference voltage, but alternately inputs a positive excitation voltage and a negative excitation voltage, and the positive input end of the operational amplifier (OA1-OAn) no longer alternately inputs a positive excitation voltage and a negative excitation voltage, but inputs a fixed reference voltage. Other technical features and the capacitance value sensing calculation principle of the pressure sensing capacitor are the same, and the repetitive content will not be repeated here.

[0122] In this embodiment, the driving end of each row of pressure sensing capacitors in the capacitive pressure sensing array 110 is connected to the excitation voltage S1, and the excitation voltage S1 is a positive excitation voltage and a negative excitation voltage that are input alternately. In one implementation, the driving end of each row of pressure sensing capacitors inputs the positive excitation voltage and the negative excitation voltage through at least one selection switch (SW1-SWm).

[0123] In this embodiment, in each capacitance-pressure conversion unit 120, the non-phase input terminal of the operational amplifier (OA1-OAn) inputs a driving voltage S0, and the driving voltage S0 is equal to a fixed reference voltage. When the driving terminal of each row of pressure sensing capacitors alternately inputs a positive excitation voltage and a negative excitation voltage, the output terminal of the operational amplifier (OA1-OAn) can output a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively, and the first detection voltage and the second detection voltage can be detected by the control unit 130 connected to the output terminal of the operational amplifier (OA1-OAn). The control unit 130 can calculate the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitude of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor (Cr1-Crn).

[0124] In some embodiments, the control unit 130 may include analog-to-digital conversion (ADC) channels of a number corresponding to the number of columns n of the m-row and n-column pressure sensing capacitors, and the output terminals of the operational amplifiers (OA1-OAn) corresponding to each column are respectively connected to the corresponding analog-to-digital conversion (ADC) channels. Under the combined effect of the driving voltage S0 (i.e., the reference voltage Vref) input to the non-inverting input terminal of the operational amplifier (OA1-OAn) and the excitation voltage S1 input to the driving terminal of the pressure sensing capacitor of the target row, the first detection voltage and the second detection voltage output from the output terminal of the operational amplifier (OA1-OAn) are input to the analog-to-digital conversion (ADC) channel corresponding to the control unit 130, and the capacitance value of each pressure sensing capacitor of the target row is calculated after analog-to-digital conversion.

[0125] In this embodiment, the control unit 130 can calculate the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor. In one implementation, the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors calculated based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0126] The ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0127] The calculation principle of the sensing capacitance calculation formula can be combined with Figure 5 It is derived through the similar principle as mentioned above.

[0128] like Figure 5 As shown, it is assumed that the capacitance value of the pressure sensing capacitor C11 is expressed as , the capacitance value of the reference capacitor Cr1 is expressed as , the reference voltage input to the non-inverting input terminal of the operational amplifier OA1 is expressed as Vref, and the amplitude of the positive excitation voltage input to the driving terminal of the pressure sensing capacitor C11 is expressed as , the amplitude of the negative excitation voltage is expressed as When the driving end of the pressure sensing capacitor C11 first changes from the input reference voltage to the input forward excitation voltage for a predetermined time, the input voltage of the driving end of the pressure sensing capacitor C11 changes from the reference voltage Vref to At this time, the first detection voltage corresponding to the forward excitation voltage at the output end of the operational amplifier OA1 is expressed as , then we can further get:

[0129] .

[0130] When the driving end of the pressure sensing capacitor C11 changes from the input reference voltage to the input negative excitation voltage for a predetermined time, the input voltage of the driving end of the pressure sensing capacitor C11 changes from the reference voltage Vref to At this time, the second detection voltage corresponding to the negative excitation voltage at the output terminal of the operational amplifier OA1 is expressed as , then we can further get:

[0131] .

[0132] Subtracting the above two formulas, we can further deduce:

[0133] ;

[0134] Thus, formula (3) can be obtained as follows:

[0135] (3).

[0136] Similarly, when the driving end of the pressure sensing capacitor C11 first changes from the input reference voltage to the input negative excitation voltage for a predetermined time, the input voltage of the driving end of the pressure sensing capacitor C11 changes from the reference voltage Vref to At this point, we can further obtain:

[0137] .

[0138] When the driving end of the pressure sensing capacitor C11 changes from the input reference voltage to the input forward excitation voltage for a predetermined time, the input voltage at the driving end of the pressure sensing capacitor C11 changes from the reference voltage Vref to . At this point, we can further get:

[0139] .

[0140] Subtracting the above two formulas, we can also further deduce:

[0141] .

[0142] Therefore, the above formula (3) can also be obtained.

[0143] It can be seen that the capacitance value of the pressure sensing capacitor C11 is highly correlated with the ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage, and the capacitance value of the reference capacitor. Therefore, the control unit 130 can calculate the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

[0144] The sensing calculation method of the pressure sensing capacitor of the control unit 130 can quickly and accurately calculate the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the difference between the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor by alternately inputting a positive excitation voltage and a negative excitation voltage into the driving end of the pressure sensing capacitor. This can significantly improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor and meet the needs of high-precision pressure distribution measurement in different scenarios.

[0145] In summary, the sensing circuit of the embodiment of the present application alternately inputs a positive excitation voltage and a negative excitation voltage at the driving end of the pressure sensing capacitor, the inverting input end of the operational amplifier is connected to the detection end of the pressure sensing capacitor of the corresponding column, and a reference voltage is input at the non-phase input end of the operational amplifier to obtain the first detection voltage and the second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage output by the output end of the operational amplifier, respectively. Therefore, the control unit can quickly calculate the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor, which can significantly improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor and meet the needs of high-precision pressure distribution measurement in different scenarios.

[0146] In some embodiments, the driving end of the pressure sensing capacitor is configured to alternately input a positive excitation voltage and a negative excitation voltage, including:

[0147] The driving end of the pressure sensing capacitor sequentially inputs a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude, or the driving end of the pressure sensing capacitor sequentially inputs a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

[0148] In this embodiment, the positive excitation voltage and the negative excitation voltage are symmetrical excitation voltages with the same excitation time, equal amplitude, and opposite polarity. By alternately inputting symmetrical excitation voltages with the same excitation time, equal amplitude, and opposite polarity to the driving end of the pressure sensing capacitor, the order of inputting the positive excitation voltage and the negative excitation voltage can be arbitrarily exchanged, which can effectively avoid the polarization and electrolytic failure caused by the long-term DC deviation of the pressure sensing capacitor in the capacitive sensing array, especially in the application scenario of the capacitive pressure sensing array composed of ionic capacitive pressure sensors, which can significantly improve the service life and detection accuracy of the capacitive pressure sensing array 110.

[0149] In some implementations, the control unit 130 calculates the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor, which may further include:

[0150] The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0151] In this embodiment, according to the above formula, the control unit 130 can calculate the capacitance value of the pressure sensing capacitor of the target row in the m-row and n-column pressure sensing capacitor based on the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage, the difference between the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor. Then, further, the sensing capacitance calculation formula can also be combined with Figure 5 Further deduction is as follows:

[0152] like Figure 5 As shown, it is assumed that the positive excitation voltage and the negative excitation voltage input to the driving end of the pressure sensing capacitor are symmetrical excitation voltages with the same excitation time and equal amplitude. It is assumed that the amplitudes of the positive excitation voltage and the negative excitation voltage are expressed as When the driving end of the pressure sensing capacitor first changes from the input reference voltage to the input forward excitation voltage for a predetermined time, the input voltage of the driving end of the pressure sensing capacitor changes from the reference voltage Vref to At this point, according to the above formula, we can further obtain:

[0153] .

[0154] When the driving end of the pressure sensing capacitor C11 changes from the input reference voltage to the input negative excitation voltage for a predetermined time, the input voltage of the driving end of the pressure sensing capacitor C11 changes from the reference voltage Vref to At this time, the second detection voltage corresponding to the negative excitation voltage at the output terminal of the operational amplifier OA1 is expressed as , then we can further get:

[0155] .

[0156] Subtracting the above two formulas, we can further deduce:

[0157] ;

[0158] Thus, formula (4) can be obtained as follows:

[0159] (4).

[0160] Similarly, when the driving end of the pressure sensing capacitor C11 first changes from the input reference voltage to the input negative excitation voltage for a predetermined time, the input voltage of the driving end of the pressure sensing capacitor C11 changes from the reference voltage Vref to At this point, we can further obtain:

[0161] .

[0162] When the driving end of the pressure sensing capacitor C11 changes from the input reference voltage to the input forward excitation voltage for a predetermined time, the input voltage at the driving end of the pressure sensing capacitor C11 changes from the reference voltage Vref to . At this point, we can further get:

[0163] .

[0164] Subtracting the above two formulas, we can also further deduce:

[0165] ;

[0166] Thus, the above formula (4) can also be obtained. It can be seen that formula (4) can also be equivalent to replacing the amplitudes of the positive excitation voltage and the negative excitation voltage with the same amplitude in formula (3): And get.

[0167] Therefore, in this embodiment, the capacitance value of the pressure sensing capacitor C11 is highly correlated with the ratio of the difference between the first detection voltage and the second detection voltage to twice the amplitude of the positive excitation voltage and the negative excitation voltage, and the capacitance value of the reference capacitor. This embodiment is based on calculating the ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage, and based on the product of the ratio and the capacitance value of the reference capacitor to calculate the capacitance value of the pressure sensing capacitor. The sensing calculation method of the pressure sensing capacitor of the control unit 130 can quickly and accurately calculate the capacitance value of the pressure sensing capacitor of the target row by alternately inputting a symmetrical positive excitation voltage and a negative excitation voltage of equal amplitude into the driving end of the pressure sensing capacitor. Based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the difference between the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor. On the basis of any of the aforementioned implementation modes, the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor can be further significantly improved. At the same time, the service life of the capacitive pressure sensor array and its adaptability to different pressure sensing scenarios can also be improved, thereby meeting the needs of high-precision pressure distribution measurement in different scenarios.

[0168] In some implementations, the driving end of the pressure sensing capacitor may be further configured to input a reference voltage before inputting a positive excitation voltage and a negative excitation voltage to clear the charges of the pressure sensing capacitor and the reference capacitor of the target row.

[0169] In this embodiment, in order to ensure the sensing accuracy of the pressure sensing capacitor of the target row and avoid being affected by the parasitic capacitance of the pressure sensing capacitor and the reference capacitor, before the positive excitation voltage and the negative excitation voltage are alternately input to the driving end of the pressure sensing capacitor each time, the reference voltage Vref can be input to the driving end of the pressure sensing capacitor to clear the charge of the pressure sensing capacitor and the reference capacitor, so that the pressure sensing capacitor of the target row and the reference capacitor in the capacitive-pressure conversion unit 120 of the corresponding column are in a state of charge clearing before each detection cycle of the capacitive-pressure conversion unit 120 starts. When the reference voltage Vref is input to the driving end of the pressure sensing capacitor, since the reference voltage Vref is also input to the positive input end of the operational amplifier, due to the voltage following effect of the operational amplifier (OA1-OAn) at this time, the voltages at both ends of the pressure sensing capacitor of the target row and the reference capacitor in the capacitive-pressure conversion unit 120 of the corresponding column are both at the reference voltage, which essentially causes the pressure sensing capacitor and the reference capacitor to be in a state of charge clearing.

[0170] In one embodiment, the sensing circuit 300 of the capacitive pressure sensing array of this embodiment, based on the previous embodiment, further includes: a multi-way selection unit 140, which is used to connect the detection ends of at least one column of pressure sensing capacitors to the inverting input end of at least one operational amplifier (OA1-OAa) in sequence.

[0171] In this embodiment, the number a of the capacitance-pressure conversion units 120 depends on the number a of the analog-to-digital conversion (ADC) channels of the control unit 130. When the number a of the analog-to-digital conversion (ADC) channels of the control unit 130 is less than the number n of columns of the m rows and n columns of pressure sensing capacitors, that is, it is insufficient to meet the detection requirements of the pressure sensing capacitors of all columns of the m rows and n columns of pressure sensing capacitors, the detection ends of the n columns of pressure sensing capacitors can be connected to the inverting input ends of the corresponding operational amplifiers (OA1-OAa) in a capacitance-pressure conversion units 120 in a sequentially selected manner through the multi-way selection unit 140.

[0172] For example, when the number of analog-to-digital conversion (ADC) channels of the control unit 130 is 1, the number of the capacitive-pressure conversion unit 120 is 1, and the one capacitive-pressure conversion unit 120 includes an operational amplifier (OA1). At this time, the multiplexer 140 can connect the detection ends of all n columns of pressure sensing capacitors to the inverting input end of the operational amplifier (OA1) of the capacitive-pressure conversion unit 120 in a sequentially selected manner; when the number of analog-to-digital conversion (ADC) channels of the control unit 130 is 2, the number of the capacitive-pressure conversion unit 120 is 2, and the two capacitive-pressure conversion units 120 include operational amplifiers (OA1, OA2). At this time, the multiplexer 140 can connect the detection ends of all n columns of pressure sensing capacitors to the inverting input end of the operational amplifier (OA1) of the capacitive-pressure conversion unit 120 in a sequentially selected manner. The detection ends of every two columns of pressure sensing capacitors in the pressure sensing capacitor are connected to the inverting input ends of the operational amplifiers (OA1, OA2) of the capacitive-pressure conversion unit 120 in a sequentially selected manner; similarly, by analogy, when the number of analog-to-digital conversion (ADC) channels of the control unit 130 is a, a is less than n, the number of the capacitive-pressure conversion units 120 is a, and the a capacitive-pressure conversion units 120 include operational amplifiers (OA1-OAa). At this time, the multiplexing unit 140 can connect the detection ends of each a column of pressure sensing capacitors in all n columns of pressure sensing capacitors to the inverting input ends of the operational amplifiers (OA1-OAa) of the capacitive-pressure conversion unit 120 in a sequentially selected manner.

[0173] It can be understood that when the number of analog-to-digital conversion (ADC) channels of the control unit 130 is n, the number of the capacitive-pressure conversion units 120 is n, and the n capacitive-pressure conversion units 120 include operational amplifiers (OA1-OAn). At this time, all the paths of the multi-way selection unit 140 are enabled, that is, the detection ends of all n columns of pressure sensing capacitors can be simultaneously connected to the inverting input ends of the operational amplifiers (OA1-OAn) of the n capacitive-pressure conversion units 120.

[0174] In some implementations, the reference capacitor (Cr1-Crn) in each capacitance-voltage conversion unit 120 may include a parallel capacitor group formed by connecting multiple capacitors in parallel. Figure 6 As shown, Figure 6 The reference capacitor Cr1 in the capacitance-pressure conversion unit 120 corresponding to the pressure sensing capacitor in the first column is shown to include a parallel capacitor group of two capacitors Cr11 and Cr12. In this case, the capacitance value of the reference capacitor (Cr1-Crn) is equivalent to the equivalent capacitance value of the parallel capacitor group.

[0175] Figure 7 FIG. 1 is a flow chart of a sensing method of a capacitive pressure sensing array according to the first embodiment of the present application. Figure 7 As shown, the sensing method of the capacitive pressure sensing array of this embodiment is applied to the sensing circuit of the capacitive pressure sensing array of the first embodiment or the second embodiment and its subsidiary embodiments, and includes the following steps:

[0176] Step S710, alternately inputting a positive excitation voltage and a negative excitation voltage into the non-phase input terminal of the operational amplifier, so as to detect a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage respectively from the output terminal of the operational amplifier;

[0177] Step S720 , calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

[0178] In one embodiment, the step of calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0179] The ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0180] In one embodiment, the alternately inputting a positive excitation voltage and a negative excitation voltage to the non-phase input terminal of the operational amplifier comprises:

[0181] A positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude are sequentially input to the non-inverting input terminal of the operational amplifier, or a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude are sequentially input to the non-inverting input terminal of the operational amplifier.

[0182] In one embodiment, the step of calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0183] The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0184] In one embodiment, the method further includes: before inputting a positive excitation voltage and a negative excitation voltage to the positive input terminal of the operational amplifier, inputting a reference voltage to the positive input terminal of the operational amplifier to clear the charge of the pressure sensing capacitor and the reference capacitor of the target row.

[0185] Figure 8 FIG. 1 is a flow chart of a sensing method of a capacitive pressure sensing array according to a second embodiment of the present application. Figure 8 As shown, the sensing method of the capacitive pressure sensing array of this embodiment is applied to the sensing circuit of the capacitive pressure sensing array of the third embodiment and its subsidiary embodiments, and includes the following steps:

[0186] Step S810, alternately inputting a positive excitation voltage and a negative excitation voltage to the driving end of the pressure sensing capacitor of the target row, so as to detect a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage respectively from the output end of the operational amplifier;

[0187] Step S820 , calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

[0188] In one embodiment, the step of calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0189] The ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0190] In one embodiment, the alternately inputting a positive excitation voltage and a negative excitation voltage to the driving end of the pressure sensing capacitor of the target row includes:

[0191] A positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude are sequentially input to the driving end of the pressure sensing capacitor of the target row, or a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude are sequentially input to the driving end of the pressure sensing capacitor of the target row.

[0192] In one embodiment, the step of calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes:

[0193] The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

[0194] In one embodiment, the method includes: before inputting a positive excitation voltage and a negative excitation voltage to the driving end of the pressure sensing capacitor of the target row, inputting a reference voltage to the driving end of the pressure sensing capacitor of the target row to clear the charge of the pressure sensing capacitor and the reference capacitor of the target row.

[0195] In summary, the sensing circuit and sensing method of the capacitive pressure sensing array of the embodiment of the present application, by inputting a reference voltage at the driving end of the pressure sensing capacitor, alternately inputting a positive excitation voltage and a negative excitation voltage at the positive phase input end of the operational amplifier, or alternately inputting a positive excitation voltage and a negative excitation voltage at the driving end of the pressure sensing capacitor, inputting a reference voltage at the positive phase input end of the operational amplifier, and connecting the inverting input end of the operational amplifier to the detection end of the pressure sensing capacitor of the corresponding column, so as to obtain the first detection voltage and the second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage outputted from the output end of the operational amplifier, respectively, so that the control unit can quickly calculate the capacitance value of the pressure sensing capacitor of the target row based on the amplitude of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor, which can significantly improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor, and meet the needs of high-precision pressure distribution measurement in different application scenarios such as medical devices.

[0196] The above describes the exemplary embodiments of the present application. It should be understood that the above exemplary embodiments are not restrictive but illustrative, and the protection scope of the present application is not limited thereto. It should be understood that those skilled in the art can modify and vary the embodiments of the present application without departing from the spirit and scope of the present application, and these modifications and variations should be within the protection scope of the present application.

Claims

1. A sensing circuit of a capacitive pressure sensing array, characterized in that: include: A capacitive pressure sensing array, comprising m rows and n columns of pressure sensing capacitors, a reference voltage is input to a driving end of the pressure sensing capacitor, and m and n are integers greater than or equal to 1; At least one capacitance-pressure conversion unit, each capacitance-pressure conversion unit includes an operational amplifier and a reference capacitor, two ends of the reference capacitor are respectively connected to the inverting input terminal and the output terminal of the operational amplifier, the inverting input terminal of the operational amplifier is connected to the detection terminal of the pressure sensing capacitor of the corresponding column among the m rows and n columns of pressure sensing capacitors; the non-inverting input terminal of the operational amplifier is configured to alternately input a positive excitation voltage and a negative excitation voltage, and the output terminal of the operational amplifier outputs a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively; A control unit is connected to the output end of the operational amplifier and is used to calculate the capacitance value of the pressure sensing capacitor of the target row among the m rows and n columns of pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

2. The sensing circuit of the capacitive pressure sensing array according to claim 1, characterized in that: The positive phase input terminal of the operational amplifier is configured to alternately input a positive excitation voltage and a negative excitation voltage, including: the positive phase input terminal of the operational amplifier sequentially inputs a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude, or the positive phase input terminal of the operational amplifier sequentially inputs a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

3. The sensing circuit of the capacitive pressure sensing array according to claim 1, characterized in that: The step of calculating the capacitance value of the pressure sensing capacitor of the target row among the m rows and n columns of pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor comprises: The ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

4. The sensing circuit of the capacitive pressure sensing array according to claim 2, characterized in that: The step of calculating the capacitance value of the pressure sensing capacitor of the target row among the m rows and n columns of pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor comprises: The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

5. The sensing circuit of the capacitive pressure sensing array according to claim 1, characterized in that: The non-inverting input terminal of the operational amplifier is configured to input a reference voltage before inputting a positive excitation voltage and a negative excitation voltage to clear charges of the pressure sensing capacitor and the reference capacitor of the target row.

6. The sensing circuit of the capacitive pressure sensing array according to claim 1, characterized in that: The reference voltage is input to the driving end of the pressure sensing capacitor through at least one gate switch.

7. The sensing circuit of the capacitive pressure sensing array according to claim 1, characterized in that: The sensing circuit further comprises a multi-way selection unit, and the multi-way selection unit is used to sequentially connect the detection ends of at least one column of pressure sensing capacitors to the inverting input end of at least one operational amplifier.

8. A sensing circuit of a capacitive pressure sensing array, characterized in that: include: A capacitive pressure sensing array, comprising m rows and n columns of pressure sensing capacitors, wherein a driving end of the pressure sensing capacitor is configured to alternately input a positive excitation voltage and a negative excitation voltage, and m and n are integers greater than or equal to 1; At least one capacitance-pressure conversion unit, each capacitance-pressure conversion unit includes an operational amplifier and a reference capacitor, two ends of the reference capacitor are respectively connected to the inverting input terminal and the output terminal of the operational amplifier, the inverting input terminal of the operational amplifier is connected to the detection terminal of the pressure sensing capacitor of the corresponding column among the m rows and n columns of pressure sensing capacitors; the positive input terminal of the operational amplifier inputs a reference voltage, and the output terminal of the operational amplifier outputs a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively; A control unit is connected to the output end of the operational amplifier and is used to calculate the capacitance value of the pressure sensing capacitor of the target row among the m rows and n columns of pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

9. The sensing circuit of the capacitive pressure sensing array according to claim 8, characterized in that: The driving end of the pressure sensing capacitor is configured to alternately input a positive excitation voltage and a negative excitation voltage, including: the driving end of the pressure sensing capacitor sequentially inputs a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude, or the driving end of the pressure sensing capacitor sequentially inputs a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

10. The sensing circuit of the capacitive pressure sensing array according to claim 9, characterized in that: The step of calculating the capacitance value of the pressure sensing capacitor of the target row among the m rows and n columns of pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor comprises: The ratio of the difference between the first detection voltage and the second detection voltage to the sum of the amplitudes of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

11. The sensing circuit of the capacitive pressure sensing array according to claim 9, characterized in that: The method of calculating the capacitance value of the pressure sensing capacitor in the target row of the m-row and n-column pressure sensing capacitors based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor includes: calculating the ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage, and calculating the capacitance value of the pressure sensing capacitor based on the product of the ratio and the capacitance value of the reference capacitor.

12. The sensing circuit of the capacitive pressure sensing array according to claim 8, characterized in that: The driving end of the pressure sensing capacitor is configured to input a reference voltage before inputting a positive excitation voltage and a negative excitation voltage to clear the charges of the pressure sensing capacitor and the reference capacitor of the target row.

13. The sensing circuit of the capacitive pressure sensing array according to claim 8, characterized in that: The driving end of the pressure sensing capacitor is input with the positive excitation voltage and the negative excitation voltage through at least one gate switch.

14. The sensing circuit of the capacitive pressure sensing array according to claim 8, characterized in that: The sensing circuit further comprises a multi-way selection unit, and the multi-way selection unit is used to sequentially connect the detection ends of at least one column of pressure sensing capacitors to the inverting input end of at least one operational amplifier.

15. A sensing method of a capacitive pressure sensing array, applied to a sensing circuit of a capacitive pressure sensing array as claimed in any one of claims 1 to 7, characterized in that: include: Alternately inputting a positive excitation voltage and a negative excitation voltage into the non-phase input terminal of the operational amplifier, so as to detect a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively, from the output terminal of the operational amplifier; The capacitance value of the pressure sensing capacitor of the target row is calculated based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

16. The sensing method of the capacitive pressure sensing array according to claim 15, characterized in that: The alternately inputting a positive excitation voltage and a negative excitation voltage to the non-phase input terminal of the operational amplifier comprises: A positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude are sequentially input to the non-inverting input terminal of the operational amplifier, or a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude are sequentially input to the non-inverting input terminal of the operational amplifier.

17. The sensing method of the capacitive pressure sensing array according to claim 16, characterized in that: The step of calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor comprises: The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

18. The sensing method of the capacitive pressure sensing array according to claim 16, characterized in that: The method includes: before inputting a positive excitation voltage and a negative excitation voltage into the non-inverting input terminal of the operational amplifier, inputting a reference voltage into the non-inverting input terminal of the operational amplifier to clear the charge of the pressure sensing capacitor and the reference capacitor of the target row.

19. A sensing method of a capacitive pressure sensing array, applied to a sensing circuit of a capacitive pressure sensing array as claimed in any one of claims 8 to 14, characterized in that: include: Alternately inputting a positive excitation voltage and a negative excitation voltage to the driving end of the pressure sensing capacitor of the target row, so as to detect a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage, respectively, from the output end of the operational amplifier; The capacitance value of the pressure sensing capacitor of the target row is calculated based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor.

20. The sensing method of the capacitive pressure sensing array according to claim 19, characterized in that: The alternately inputting a positive excitation voltage and a negative excitation voltage to the driving end of the pressure sensing capacitor of the target row comprises: A positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude are sequentially input to the driving end of the pressure sensing capacitor of the target row, or a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude are sequentially input to the driving end of the pressure sensing capacitor of the target row.

21. The sensing method of the capacitive pressure sensing array according to claim 20, characterized in that: The step of calculating the capacitance value of the pressure sensing capacitor of the target row based on the amplitudes of the positive excitation voltage and the negative excitation voltage, the first detection voltage and the second detection voltage, and the capacitance value of the reference capacitor comprises: The ratio between the difference between the first detection voltage and the second detection voltage and twice the amplitude of the positive excitation voltage and the negative excitation voltage is calculated, and the capacitance value of the pressure sensing capacitor is calculated based on the product of the ratio and the capacitance value of the reference capacitor.

22. The sensing method of the capacitive pressure sensing array according to claim 20, characterized in that: The method includes: before inputting a positive excitation voltage and a negative excitation voltage to the driving end of the pressure sensing capacitor of the target row, inputting a reference voltage to the driving end of the pressure sensing capacitor of the target row to clear the charge of the pressure sensing capacitor and the reference capacitor of the target row.

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