Anti-crosstalk sensing circuit and sensing method of capacitive pressure sensing array

Abstract

The present application discloses an anti-crosstalk sensing circuit of a capacitive pressure sensing array and a sensing method thereof, which relates to the field of capacitive pressure sensing technology. The circuit alternately inputs a positive excitation voltage and a negative excitation voltage at the driving end of each row of pressure sensing capacitors through a row selection state, and the detection end of each column of pressure sensing capacitors is respectively connected to the inverting input end and the reference voltage of the corresponding operational amplifier according to the column selection state, and obtains a first detection voltage and a second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage output by the output end of the operational amplifier, respectively, and calculates 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 prevent the crosstalk phenomenon between the same row or the same column of the capacitive pressure sensing array, and significantly improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor.

Description

Technical Field

[0001] The present application relates to the field of capacitive pressure sensing technology, and in particular to an anti-crosstalk 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 it. 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 detection. However, since the sensing capacitors in the same row or column in the capacitive pressure sensor array share an electrode or dielectric layer during the capacitance detection process, when a voltage is applied to the shared electrode or dielectric layer, parasitic capacitance exists between other sensing capacitors in the same row or column and the capacitor to be measured, resulting in crosstalk between the same row or column, which reduces the detection accuracy of the conventional capacitive sensing circuit based on the capacitive pressure sensor array for the sensing capacitor, and thus cannot meet the needs of high-precision pressure distribution measurement. Therefore, there is an urgent need for an improved sensing circuit and sensing method of the capacitive pressure sensor array to solve the above technical problems. Summary of the invention

[0003] In view of this, the present application proposes an anti-crosstalk sensing circuit and a sensing method for a capacitive pressure sensor array, which can prevent crosstalk between the same row or column of the capacitive pressure sensor array, improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the 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 an anti-crosstalk sensing circuit for a capacitive pressure sensing array, comprising:

[0005] A capacitive pressure sensing array, comprising m rows and n columns of pressure sensing capacitors, wherein a driving end of each row of the m rows and n columns of the pressure sensing capacitors is configured to input an excitation voltage and a reference voltage respectively according to a row selection state, wherein the excitation voltage comprises a positive excitation voltage and a negative excitation voltage input alternately, 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 comprises 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 non-inverting 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; the detection end of each column of the pressure sensing capacitors in the m rows and n columns is configured to be respectively connected to the corresponding inverting input terminal of the operational amplifier and the reference voltage according to the column selection state;

[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 driving end of each row of pressure sensing capacitors is configured to input the excitation voltage when the row selection state of the row is selected, and input the reference voltage when the row selection state of the row is not selected.

[0009] In some embodiments, the driving end of each row of pressure sensing capacitors is configured as: when the row selection state of the row is selected, the driving end is connected to the input path of the excitation voltage through the row selection switch; when the row selection state of the row is not selected, the driving end is connected to the input path of the reference voltage through the row selection switch.

[0010] In some embodiments, the detection end of each column of pressure sensing capacitors is configured to: connect to the inverting input end of the corresponding operational amplifier when the column selection state of the column is selected; and input the reference voltage when the column selection state of the column is not selected.

[0011] In some embodiments, the detection end of each column of pressure sensing capacitors is configured as: when the column enable state of the column is enabled, the detection end is connected to the input path of the inverting input end of the operational amplifier through the column enable switch; when the column enable state of the column is not enabled, the detection end is connected to the input path of the reference voltage through the column enable switch.

[0012] 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:

[0013] 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.

[0014] In some embodiments, the driving end of each row of pressure sensing capacitors is configured to input an excitation voltage and a reference voltage respectively according to a row selection state, including: when the row selection state of the row is selected, the driving end of each row of pressure sensing capacitors sequentially inputs a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude, or sequentially inputs a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

[0015] 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:

[0016] 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.

[0017] In some embodiments, the control unit is further configured to: when the row selection switch of the target row is switched to non-selection, control the column selection switch of each column to switch to non-selection, so that the detection end of each column of the pressure sensing capacitor inputs a reference voltage to clear the charge of the pressure sensing capacitor of the target row.

[0018] In some embodiments, the capacitance-voltage conversion unit includes a capacitance shorting switch, two ends of which are respectively connected to two ends of the reference capacitor, and the capacitance shorting switch is configured to close when the column selection state of the column is non-selected to clear the charge of the reference capacitor.

[0019] In some embodiments, a multi-way selection unit is further included, 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 in sequence when the column selection state of the column is selected.

[0020] In a second aspect, an embodiment of the present application provides a sensing method of a capacitive pressure sensing array, which is applied to an anti-crosstalk sensing circuit of a capacitive pressure sensing array as described in any of the aforementioned embodiments, comprising:

[0021] According to the row selection state of the target row, an excitation voltage and a reference voltage are respectively input to the driving end of the pressure sensing capacitor of the target row; wherein, when the row selection state of the target row is selected, a positive excitation voltage and a negative excitation voltage are alternately input to the driving end of the pressure sensing capacitor of the target row;

[0022] When the row selection state of the target row is selected, the column selection state of each column is switched to selected, and the detection end of each column of the pressure sensing capacitor is connected to the inverting input end of the corresponding operational amplifier, so as to detect the first detection voltage and the second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage respectively from the output end of the operational amplifier of each column;

[0023] 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.

[0024] In some embodiments, when the row selection state of the target row is on, 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: when the row selection state of the target row is on, sequentially inputting a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude to the driving end of the pressure sensing capacitor of the target row, or sequentially inputting a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

[0025] In some implementations, the 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:

[0026] 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.

[0027] In some implementations, the 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:

[0028] 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.

[0029] In some embodiments, the method includes: inputting a reference voltage to the driving end of the pressure sensing capacitor of the target row when the row selection state of the target row is non-selected, switching the column selection state of each column to non-selected, inputting a reference voltage to the detection end of each column of the pressure sensing capacitor to clear the charge of the pressure sensing capacitor of the target row, and short-circuiting the reference capacitor in the capacitance-pressure conversion unit corresponding to each column to clear the charge of the reference capacitor.

[0030] The embodiments of the present application can at least achieve the following beneficial effects:

[0031] In the embodiment of the present application, a positive excitation voltage and a negative excitation voltage are alternately inputted into the driving end of each row of pressure sensing capacitors according to the row selection state, and the detection end of each column of pressure sensing capacitors is respectively connected to the inverting input end and the reference voltage of the corresponding operational amplifier according to the column selection state, and the reference voltage is inputted into 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 outputted from the output end of the operational amplifier, respectively; the control unit quickly calculates 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, so that the embodiment of the present application can prevent the crosstalk phenomenon between the same row or the same column of the capacitive pressure sensor array, significantly improve the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor, and meet the requirements of high-precision pressure distribution measurement in different application scenarios such as medical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 is a schematic diagram of the circuit structure of the anti-crosstalk sensing circuit of the capacitive pressure sensing array according to the first embodiment of the present application;

[0034] Figure 2 is a schematic diagram of a capacitance-voltage conversion unit in an anti-crosstalk sensing circuit according to any embodiment of the present application;

[0035] Figure 3 is a schematic diagram of a circuit structure of an anti-crosstalk sensing circuit of a capacitive pressure sensing array according to a second embodiment of the present application;

[0036] Figure 4 is a schematic diagram of an alternative structure of a reference capacitor in an anti-crosstalk sensing circuit according to any embodiment of the present application;

[0037] Figure 5 It is a flowchart of a sensing method of a capacitive pressure sensing array according to the first embodiment of the present application. DETAILED DESCRIPTION

[0038] 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.

[0039] 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.

[0040] As mentioned above, sensing capacitors in the same row or column in a capacitive pressure sensing array, including an ionic capacitive pressure sensing array, share an electrode or dielectric layer during the capacitance detection process. When a voltage is applied to the shared electrode or dielectric layer, parasitic capacitance exists between other sensing capacitors in the same row or column and the capacitor to be measured, resulting in crosstalk between the same row or column, which reduces the detection accuracy of the conventional capacitive sensing circuit based on the capacitive pressure sensor array for the sensing capacitor, and thus cannot meet the needs of high-precision pressure distribution measurement. To this end, the present application proposes an anti-crosstalk sensing circuit and a sensing method for a capacitive pressure sensing array, which can prevent crosstalk between the same row or column of the capacitive pressure sensing array, 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.

[0041] Figure 1 FIG. 1 is a schematic diagram of a circuit structure of an anti-crosstalk sensing circuit 100 of a capacitive pressure sensing array according to the first embodiment of the present application. Figure 1 As shown, the anti-crosstalk sensing circuit 100 of the capacitive pressure sensing array of this embodiment includes:

[0042] The capacitive pressure sensing array 110 includes m rows and n columns of pressure sensing capacitors, wherein the driving end of each row of the m rows and n columns of the pressure sensing capacitors is configured to input an excitation voltage S1 and a reference voltage Vref respectively according to a row selection state, wherein the excitation voltage S1 includes a positive excitation voltage and a negative excitation voltage input alternately, and m and n are integers greater than or equal to 1;

[0043] 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 non-inverting input terminal of the operational amplifier (OA1-OAn) inputs the reference voltage Vref, and the output terminal of the operational amplifier (OA1-OAn) outputs the first detection voltage and the second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage respectively; the detection end of each column of the pressure sensing capacitors in the m rows and n columns is configured to be respectively connected to the corresponding inverting input terminal of the operational amplifier (OA1-OAn) and the reference voltage Vref according to the column selection state;

[0044] 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).

[0045] 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. Among them, the m rows and n columns of pressure sensing capacitors can be represented by rows as the first row C11-C1n, the second row C21-C2n, ..., the mth row Cm1-Cmn; according to columns, they can be represented by the first column C11-Cm1, the second column C12-Cm2, ..., the nth column C1n-Cmn.

[0046] 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. In one embodiment, the driving end of each row of pressure sensing capacitors is connected to the excitation voltage S1 when the row selection state of the row is selected, and the reference voltage Vref is input when the row selection state of the row is not selected. The excitation voltage S1 includes a positive excitation voltage and a negative excitation voltage that are alternately input, and the positive excitation voltage and the negative excitation voltage have opposite polarities. The row here refers to the row where each row of pressure sensing capacitors is currently located in the capacitive pressure sensing array 110.

[0047] In one embodiment, the driving end of each row of pressure sensing capacitors can be respectively input with the excitation voltage S1 and the reference voltage Vref through the row selection switch (SW1-SWm) of each row. For example, the driving end of the pressure sensing capacitors C11-C1n in the first row is respectively input with the excitation voltage S1 and the reference voltage Vref through the two paths of the row selection switch SW1; the driving end of the pressure sensing capacitors C21-C2n in the second row is respectively input with the excitation voltage S1 and the reference voltage Vref through the two paths of the row selection switch SW2; and so on, the detection end of the pressure sensing capacitors Cm1-Cmn in the mth row is respectively input with the excitation voltage S1 and the reference voltage Vref through the two paths of the row selection switch SWm.

[0048] In one embodiment, when the row selection state of the row is selected, the driving end of each row of pressure sensing capacitors is connected to the input path of the excitation voltage through the row selection switch (SW1-SWm) of each row, so that the driving end of each row of pressure sensing capacitors inputs the excitation voltage S1; when the row selection state of the row is non-selected, the driving end of each row of pressure sensing capacitors is connected to the input path of the reference voltage Vref through the row selection switch (SW1-SWm) of each row, so that the driving end of each row of pressure sensing capacitors inputs the reference voltage Vref.

[0049] In this embodiment, each capacitance-pressure conversion unit 120 includes an operational amplifier (OA1-OAn) and a reference capacitor (Cr1-Crn), and the 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 detection end of each column of the pressure sensing capacitors in the m rows and n columns is configured to be respectively connected to the inverting input terminal of the corresponding operational amplifier (OA1-OAn) and the reference voltage Vref according to the column selection state.

[0050] In one embodiment, the detection end of each column of the m rows and n columns of pressure sensing capacitors is configured as: when the column selection state of the column is selected, it is connected to the inverting input end of the corresponding operational amplifier; when the column selection state of the column is not selected, the reference voltage Vref is input. In one embodiment, when the row selection state of the target row is selected, that is, the driving end of the pressure sensing capacitor of the target row inputs the excitation voltage S1, at this time, the column selection state of each column is switched to selected, and the detection end of each column of the pressure sensing capacitor is connected to the inverting input end of the corresponding operational amplifier. The column here refers to the column where each column of pressure sensing capacitors is currently located in the capacitive pressure sensing array 110.

[0051] In one embodiment, the detection end of each column of the pressure sensing capacitors in the m rows and n columns is configured to be connected to the inverting input terminal of the corresponding operational amplifier (OA1-OAn) and the reference voltage Vref through the column selection switch (SWc1-SWcn) of each column. For example, the detection end of the pressure sensing capacitors C11-Cm1 in the first column is connected to the inverting input terminal of the operational amplifier OA1 and the reference voltage Vref through the two paths of the column selection switch SWc1; the detection end of the pressure sensing capacitors C12-Cm2 in the second column is connected to the inverting input terminal of the operational amplifier OA2 and the reference voltage Vref through the two paths of the column selection switch SWc2; and so on, the detection end of the pressure sensing capacitors C1n-Cmn in the nth column is connected to the inverting input terminal of the operational amplifier OAn and the reference voltage Vref through the two paths of the column selection switch SWcn. In one embodiment, the detection end of each column of the m rows and n columns of pressure sensing capacitors is configured as follows: when the column selection state of the column is selected, the detection end of each column of the pressure sensing capacitor is connected to the input path of the inverting input terminal of the operational amplifier through the column selection switch (SWc1-SWcn) of each column, so that the detection end of each column of the pressure sensing capacitor is connected to the inverting input terminal of the corresponding operational amplifier; when the column selection state of the column is non-selected, the detection end of each column of the pressure sensing capacitor is connected to the input path of the reference voltage Vref through the column selection switch (SWc1-SWcn) of each column, so that the reference voltage Vref is input to the detection end of each column of the pressure sensing capacitor.

[0052] In this embodiment, in each capacitance-pressure conversion unit 120, the reference voltage Vref is input to the non-phase input terminal of the operational amplifier (OA1-OAn), and 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. 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), and 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 the driving end of the pressure sensing capacitor of the target row is alternately input with the positive excitation voltage and the negative excitation voltage.

[0053] 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 driving terminal of the pressure sensing capacitor of the target row and the reference voltage Vref input to the non-inverting input terminal of the operational amplifier (OA1-OAn) corresponding to each column, 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.

[0054] 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:

[0055] 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.

[0056] The calculation principle of the sensing capacitance calculation formula in this embodiment can be combined with Figure 2 It is derived through the following formula. 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 driving end of the pressure sensing capacitor C11 inputs the excitation voltage S1 through the row selection switch SW1, the reference voltage Vref is input to the positive input end of the operational amplifier OA1, and the detection end of the pressure sensing capacitor C11 is connected to the inverting input end of the operational amplifier OA1 through the column selection switch SWc1, then the voltage at both ends of 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 amount of charge changed by the pressure sensing capacitor C11 is basically the same as the amount of charge changed by the reference capacitor Cr1. Assume that the amount of charge changed by the pressure sensing capacitor C11 is expressed as , the charge change of reference capacitor Cr1 is expressed as , then we can conclude .

[0057] 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:

[0058] ;

[0059] Assume that the reference voltage input to the non-inverting input terminal of the operational amplifier OA1 is expressed as Vref, and the amplitude of the forward 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 changes from the input reference voltage to the input forward excitation voltage for a predetermined time through the row selection switch SW1, 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 outputted from the output terminal of the operational amplifier OA1 is expressed as , then we can further get:

[0060] .

[0061] 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 through the row selection switch SW1, 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 outputted from the output terminal of the operational amplifier OA1 is expressed as , then we can further get:

[0062] .

[0063] Subtracting the above two formulas, we can further deduce:

[0064] ;

[0065] Thus, formula (1) can be obtained as follows:

[0066] (1).

[0067] Similarly, 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 through the row selection switch SW1, 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:

[0068] .

[0069] 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 through the row selection switch SW1, 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 get:

[0070] .

[0071] Subtracting the above two formulas, we can also further deduce:

[0072] .

[0073] Therefore, the above formula (1) can also be obtained.

[0074] 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.

[0075] 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 positive excitation voltage and a negative excitation voltage to 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; at the same time, when the row selection state of the target row is selected and the row selection states of other rows are not selected, the column selection state of each column is selected, that is, only the driving end of the pressure sensing capacitor of the target row inputs the excitation voltage S1, and the driving end of the pressure sensing capacitor of other rows inputs the reference voltage Vref. Because the column selection state of the pressure sensing capacitor of each column is selected, the pressure sensing capacitor of each column is selected. The detection end of the pressure sensing capacitor is connected to the inverting input end of the corresponding operational amplifier. Since the reference voltage Vref is input to the non-inverting input end of the operational amplifier, and the driving end of the pressure sensing capacitors in other rows is also input to 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 capacitors in other rows are in a voltage balance state of the reference voltage Vref, so that the pressure sensing capacitors in other rows are substantially in a charge clearing state, avoiding the crosstalk problem of the capacitance detection of the pressure sensing capacitors in the target row; in addition, since the detection end of the pressure sensing capacitor in each column is respectively connected to the inverting input end of the corresponding operational amplifier, the capacitance change of the pressure sensing capacitors in different columns will not interfere with the capacitance detection of the pressure sensing capacitors in other columns. Therefore, the embodiment of the present application can prevent the crosstalk phenomenon between the same row or the same column of the capacitive pressure sensing array, 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.

[0076] In summary, the anti-crosstalk sensing circuit of the capacitive pressure sensing array of the embodiment of the present application alternately inputs positive excitation voltage and negative excitation voltage at the driving end of each row of pressure sensing capacitors according to the row selection state, and the detection end of each column of pressure sensing capacitors is respectively connected to the inverting input terminal and the reference voltage of the corresponding operational amplifier according to the column selection state, and the reference voltage is input to the positive input terminal 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 terminal 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 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 prevent crosstalk between the same row or column of the capacitive pressure sensing array, 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.

[0077] In some implementations, the driving end of each row of pressure sensing capacitors is configured to input an excitation voltage and a reference voltage respectively according to a row selection state, which may include:

[0078] When the row selection state of the row is selected, a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude are input in sequence, or a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude are input in sequence; when the row selection state of the row is non-selected, a reference voltage is input.

[0079] In this embodiment, the positive excitation voltage and the negative excitation voltage are excitation voltages with the same excitation time, equal amplitude, and opposite polarity. By alternately inputting excitation voltages with the same excitation time, equal amplitude, and opposite polarity to the driving end of each row of pressure sensing capacitors, 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 bias of the pressure sensing capacitors 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.

[0080] 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:

[0081] 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.

[0082] In this embodiment, according to the above formula, the sensing capacitance calculation formula can also be combined with Figure 2 Further deduction is as follows:

[0083] like Figure 2 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 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 changes from the input reference voltage to the input forward excitation voltage for a predetermined time through the row selection switch SW1, 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:

[0084] .

[0085] 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 through the row selection switch SW1, 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:

[0086] .

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

[0088] ;

[0089] Thus, formula (2) can be obtained as follows:

[0090] (2).

[0091] Similarly, 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 through the row selection switch SW1, 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:

[0092] .

[0093] 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 through the row selection switch SW1, 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 get:

[0094] .

[0095] Subtracting the above two formulas, we can also further deduce:

[0096] ;

[0097] Thus, the above formula (2) can also be obtained. It can be seen that formula (2) can also be equivalent to replacing the amplitudes of the positive excitation voltage and the negative excitation voltage with the same amplitude in formula (1): And get.

[0098] 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 and 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, the capacitance value of the pressure sensing capacitor can be calculated. 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.

[0099] In some embodiments, the control unit 130 is further configured to: when the row selection switch of the target row is switched to non-selection, control the column selection switch of each column to switch to non-selection, so that the detection end of each column of the pressure sensing capacitor inputs a reference voltage to clear the charge of the pressure sensing capacitor of the target row.

[0100] In some embodiments, each capacitance-voltage conversion unit 120 includes a capacitance shorting switch (SWr1-SWrn), two ends of the capacitance shorting switch (SWr1-SWrn) are respectively connected to two ends of the reference capacitor (Cr1-Crn), and the capacitance shorting switch (SWr1-SWrn) is configured to be closed when the column selection state of the column is non-selected to clear the charge of the reference capacitor.

[0101] In one embodiment, the control unit 130 is further configured to: when the column selection switch of the column is switched to non-selection, control the capacitor shorting switch in the capacitance-voltage conversion unit 120 corresponding to the column to close to clear the charge of the reference capacitor.

[0102] 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 each alternate input of the positive excitation voltage and the negative excitation voltage to the driving end of the pressure sensing capacitor of the target row, the row selection switch of the target row can be switched to non-selected so that the driving end of the pressure sensing capacitor of the target row is input with the reference voltage. At this time, the column selection switch of each column is switched to non-selected so that the detection end of each column of the pressure sensing capacitor is also input with the reference voltage, so as to achieve voltage balance at both ends of the pressure sensing capacitor of the target row to clear the charge of the pressure sensing capacitor of the target row. In addition, the capacitor shorting switch of each capacitance-pressure conversion unit is closed to clear the charge of the reference capacitor. Thus, before or after the detection cycle of each target row starts, the pressure sensing capacitor of each target row and the reference capacitor in the capacitance-pressure conversion unit 120 of the corresponding column are in a state of charge clearing, which further ensures the detection accuracy of the sensing circuit of the capacitive pressure sensor array for the sensing capacitor.

[0103] Figure 3 FIG. 2 is a schematic diagram of a circuit structure of an anti-crosstalk sensing circuit 200 of a capacitive pressure sensing array according to a second embodiment of the present application. Figure 3 As shown, the anti-crosstalk 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 ends of at least one operational amplifier (OA1-OAa) in sequence when the column selection state of the column is selected.

[0104] 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 multi-way selection unit 140 can connect the detection ends of the n columns of pressure sensing capacitors to the inverting input ends of the corresponding operational amplifiers (OA1-OAa) in a capacitance-pressure conversion units 120 in a sequentially selected manner when the column selection state of the column is selected.

[0105] 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 multi-way selection unit 140 can connect the detection ends of the pressure sensing capacitors of all n columns to the inverting input end of the operational amplifier (OA1) of the capacitive-pressure conversion unit 120 in a sequentially selected manner when the column selection state of the column is selected; 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 multi-way selection unit 140 can connect the detection ends of the pressure sensing capacitors of all n columns to the inverting input end of the operational amplifier (OA1) of the capacitive-pressure conversion unit 120 in a sequentially selected manner when the column selection state of the column is selected. When the detection ends of every two columns of pressure sensing capacitors in all n columns of pressure sensing capacitors are connected to the inverting input end of the operational amplifier (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 every a columns of pressure sensing capacitors in all n columns of pressure sensing capacitors to the inverting input end of the operational amplifier (OA1-OAa) of the capacitive-pressure conversion unit 120 in a sequentially selected manner when the column selection state of the column is selected.

[0106] 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 an operational amplifier (OA1-OAn). At this time, all the paths of the multi-way selection unit 140 are enabled, that is, the detection ends of the pressure sensing capacitors of all n columns can be simultaneously connected to the inverting input ends of the operational amplifiers (OA1-OAn) of the n capacitive-pressure conversion units 120 when the column enabling state of the column is enabled.

[0107] 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 4 As shown, Figure 4 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.

[0108] Figure 5 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 5As shown, the sensing method of the capacitive pressure sensing array of this embodiment is applied to the anti-crosstalk 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:

[0109] Step S510, inputting an excitation voltage and a reference voltage to the driving end of the pressure sensing capacitor of the target row respectively according to the row selection state of the target row; wherein, when the row selection state of the target row is selected, a positive excitation voltage and a negative excitation voltage are alternately input to the driving end of the pressure sensing capacitor of the target row;

[0110] Step S520, when the row selection state of the target row is selected, switching the column selection state of each column to selected, connecting the detection end of each column of the pressure sensing capacitor to the inverting input end of the corresponding operational amplifier, so as to detect the first detection voltage and the second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage respectively from the output end of the operational amplifier of each column;

[0111] Step S530 , 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.

[0112] In some embodiments, when the row selection state of the target row is on, 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: when the row selection state of the target row is on, sequentially inputting a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude to the driving end of the pressure sensing capacitor of the target row, or sequentially inputting a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

[0113] In some implementations, the 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:

[0114] 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.

[0115] In some implementations, the 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:

[0116] 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.

[0117] In some embodiments, the method includes: inputting a reference voltage to the driving end of the pressure sensing capacitor of the target row when the row selection state of the target row is non-selected, switching the column selection state of each column to non-selected, and inputting a reference voltage to the detection end of the pressure sensing capacitor of each column to clear the charge of the pressure sensing capacitor of the target row.

[0118] In some embodiments, the method includes: when the column selection state of each column is non-selected, short-circuiting the reference capacitor in the capacitance-voltage conversion unit corresponding to each column to clear the charge of the reference capacitor.

[0119] In summary, the anti-crosstalk sensing circuit and sensing method of the capacitive pressure sensing array of the embodiment of the present application alternately inputs a positive excitation voltage and a negative excitation voltage at the driving end of each row of the pressure sensing capacitor according to the row selection state, and the detection end of each column of the pressure sensing capacitor is connected to the inverting input end and the reference voltage of the corresponding operational amplifier according to the column selection state, and the reference voltage is input to the positive 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, 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 prevent crosstalk between the same row or column of the capacitive pressure sensing array, 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.

[0120] 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 crosstalk prevention sensing circuit for 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 each row of the m rows and n columns of the pressure sensing capacitors is configured to input an excitation voltage and a reference voltage respectively according to a row selection state, wherein the excitation voltage comprises a positive excitation voltage and a negative excitation voltage input alternately, and m and n are integers greater than or equal to 1; At least one capacitance-pressure conversion unit, each capacitance-pressure conversion unit comprises 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 non-inverting 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; the detection end of each column of the pressure sensing capacitors in the m rows and n columns is configured to be respectively connected to the corresponding inverting input terminal of the operational amplifier and the reference voltage according to the column selection state; 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 anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 1, characterized in that: The driving end of each row of pressure sensing capacitors is configured to input the excitation voltage when the row selection state of the row is selection, and input the reference voltage when the row selection state of the row is non-selection.

3. The anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 2, characterized in that: The driving end of each row of pressure sensing capacitors is configured as: when the row selection state of the row is selected, it is connected to the input path of the excitation voltage through the row selection switch; when the row selection state of the row is not selected, it is connected to the input path of the reference voltage through the row selection switch.

4. The anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 2, characterized in that: The detection end of each column of pressure sensing capacitors is configured to: connect to the inverting input end of the corresponding operational amplifier when the column selection state of the column is selected; and input the reference voltage when the column selection state of the column is not selected.

5. The anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 4, characterized in that: The detection end of each column of pressure sensing capacitors is configured as: when the column enable state of the column is enabled, the detection end is connected to the input path of the inverting input end of the operational amplifier through the column enable switch; when the column enable state of the column is not enabled, the detection end is connected to the input path of the reference voltage through the column enable switch.

6. The anti-crosstalk 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.

7. The anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 2, characterized in that: The driving end of each row of pressure sensing capacitors is configured to input an excitation voltage and a reference voltage respectively according to a row selection state, including: when the row selection state of the row is selected, the driving end of each row of pressure sensing capacitors sequentially inputs a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude, or sequentially inputs a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude.

8. The anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 7, 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.

9. The anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 2, characterized in that: The control unit is also configured to: when the row selection switch of the target row is switched to non-selection, control the column selection switch of each column to switch to non-selection, so that the detection end of each column of the pressure sensing capacitor inputs a reference voltage to clear the charge of the pressure sensing capacitor of the target row.

10. The anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 9, characterized in that: The capacitance-voltage conversion unit includes a capacitance shorting switch, two ends of which are respectively connected to two ends of the reference capacitor, and the capacitance shorting switch is configured to close when the column selection state of the column is non-selected to clear the charge of the reference capacitor.

11. The anti-crosstalk sensing circuit of the capacitive pressure sensing array according to claim 1, characterized in that: It also includes a multi-way selection unit, 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 in sequence when the column selection state of the column is selected.

12. A sensing method for a capacitive pressure sensing array, applied to the anti-crosstalk sensing circuit of the capacitive pressure sensing array according to any one of claims 1 to 11, characterized in that: include: According to the row selection state of the target row, an excitation voltage and a reference voltage are respectively input to the driving end of the pressure sensing capacitor of the target row; wherein, when the row selection state of the target row is selected, a positive excitation voltage and a negative excitation voltage are alternately input to the driving end of the pressure sensing capacitor of the target row; When the row selection state of the target row is selected, the column selection state of each column is switched to selected, and the detection end of each column of the pressure sensing capacitor is connected to the inverting input end of the corresponding operational amplifier, so as to detect the first detection voltage and the second detection voltage corresponding to the positive excitation voltage and the negative excitation voltage respectively from the output end of the operational amplifier of each column; 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.

13. The sensing method of the capacitive pressure sensing array according to claim 12, 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 when the row selection state of the target row is selected includes: inputting a positive excitation voltage and a negative excitation voltage with the same excitation time and equal amplitude to the driving end of the pressure sensing capacitor of the target row in sequence when the row selection state of the target row is selected, or inputting a negative excitation voltage and a positive excitation voltage with the same excitation time and equal amplitude in sequence.

14. The sensing method of the capacitive pressure sensing array according to claim 13, 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 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.

15. The sensing method of the capacitive pressure sensing array according to claim 13, 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.

16. The sensing method of the capacitive pressure sensing array according to claim 13, characterized in that: The method includes: inputting a reference voltage to a driving end of a pressure sensing capacitor of the target row when a row selection state of the target row is non-selected, switching a column selection state of each column to non-selected, inputting a reference voltage to a detection end of a pressure sensing capacitor of each column to clear the charge of the pressure sensing capacitor of the target row, and short-circuiting a reference capacitor in a capacitance-pressure conversion unit corresponding to each column to clear the charge of the reference capacitor.

Images