A programmable digital modulation and driving circuit for pressure sensor

Abstract

The present application belongs to the field of sensor control technology, and discloses a programmable digital modulation and drive circuit of a pressure sensor, including a microprocessor, a digital signal modulator, a programmable drive control circuit and an analog-to-digital conversion circuit. The microprocessor outputs a control signal to the programmable drive control circuit, and controls the digital signal modulator to output a level signal to the programmable drive control circuit, so that the programmable drive control circuit outputs a corresponding drive signal to the pressure sensor. Then, the analog-to-digital conversion circuit converts and processes the sampling signal output by the pressure sensor, and the analog-to-digital conversion circuit feeds back the processed sampling signal to the microprocessor. When the microprocessor detects that the sampling signal is abnormal, the control signal can be adjusted, so that the sampling signal output by the pressure sensor remains within a normal range. This not only realizes adaptive closed-loop adjustment and control of drive and sampling feedback, improves the anti-interference performance of the circuit, but also ensures the sampling detection accuracy.

Description

Technical Field

[0001] The present application belongs to the field of sensor control technology, and in particular relates to a programmable digital modulation and driving circuit of a pressure sensor. Background Art

[0002] As a device that can sense pressure and convert it into a usable electrical signal, pressure sensors are widely used in various industrial automatic control environments, involving many industries such as water conservancy and hydropower, power lithium battery packs, intelligent buildings, production automatic control, aerospace, military industry, petrochemicals, oil wells, electricity, ships, machine tools, and pipelines. Among them, in industrial practice, pressure sensors are mainly divided into two categories. One is a semiconductor piezoresistive impedance diffusion pressure sensor, that is, a semiconductor deformation pressure is formed on the surface of a thin sheet, and a piezoresistive impedance effect is generated by deforming the thin sheet through external force (pressure), thereby converting the impedance change into an electrical signal; the other is an electrostatic capacitance type pressure sensor, that is, a capacitor is formed by placing the fixed pole of glass and the movable pole of silicon relative to each other, and the change in electrostatic capacitance generated by the deformation of the movable pole through external force (pressure) is converted into an electrical signal.

[0003] Since domestic pressure sensors have direct analog output, the current detection method mainly uses two sampling lines (one positive line and one negative line) to connect to the output end of the domestic pressure sensor. This design is relatively simple, but because the strain voltage sampling signal is a tiny signal (as low as a few microvolts), the signal loop is easily interfered by external high and low frequency signals, which leads to inaccurate sampling and detection of the sampling voltage; secondly, this design does not have the digital conversion and modulation process of the driving signal, and cannot effectively identify the sampling voltage during sampling back inspection, and the accuracy range cannot be controlled and corrected, further affecting the detection accuracy of the domestic pressure sensor. Summary of the invention

[0004] This application aims to solve the above-mentioned problems that the current detection method is relatively simple, but because the induced strain voltage sampling signals are all tiny signals (as low as a few microvolts), the signal circuit is easily interfered by external high and low frequency signals, which leads to inaccurate sampling detection of the sampling voltage; secondly, this design does not have a digital conversion and modulation process of the driving signal, and the sampling voltage cannot be effectively identified during sampling back inspection, and the accuracy range cannot be controlled and corrected, further affecting the detection accuracy of domestic pressure sensors. A programmable digital modulation and drive circuit of a pressure sensor is proposed, and its technical solution is as follows:

[0005] The present application provides a programmable digital modulation and drive circuit for a pressure sensor, the circuit comprising a microprocessor, a digital signal modulator, a programmable drive control circuit and an analog-to-digital conversion circuit, wherein:

[0006] The first output terminal of the microprocessor is connected to the input terminal of the digital signal modulator, the second output terminal of the microprocessor is connected to the first input terminal of the programmable drive control circuit, and the first input terminal of the microprocessor is connected to the output terminal of the analog-to-digital conversion circuit;

[0007] The output terminal of the digital signal modulator is connected to the second input terminal of the programmable drive control circuit;

[0008] The output end of the programmable drive control circuit is connected to the input end of the pressure sensor;

[0009] The first input terminal of the analog-to-digital conversion circuit is connected to the output terminal of the pressure sensor.

[0010] In an optional solution, the circuit further includes a signal matching and amplification circuit, wherein:

[0011] The first input end of the signal matching and amplifying circuit is connected to the output end of the pressure sensor, and the output end of the signal matching and amplifying circuit is connected to the first input end of the analog-to-digital conversion circuit.

[0012] In yet another alternative, the circuit further comprises a first connector, wherein:

[0013] The input end of the first connector is connected to the power supply, the first output end of the first connector is respectively connected to the second input end of the microprocessor, the third input end of the programmable drive control circuit, the second input end of the analog-to-digital conversion circuit, and the second input end of the signal matching and amplification circuit, and the second output end of the first connector is connected to the ground end.

[0014] In yet another alternative, the circuit further comprises a second connector, wherein:

[0015] The first input end of the second connector is connected to the first output end of the first connector, the second input end of the second connector is connected to the third output end of the microprocessor, the first output end of the second connector is connected to the Internet of Things device, and the second output end of the second connector is connected to the ground end.

[0016] In another optional solution, the output end of the digital signal modulator includes a first output end and a second output end, the input end of the pressure sensor includes a first input end and a second input end, and the programmable drive control circuit includes a programmable modulator, a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a power transformer, wherein:

[0017] The first input end of the programmable modulator is connected to the first output end of the first connector, the second input end of the programmable modulator is connected to the second output end of the microprocessor, the first output end of the programmable modulator is connected to the ground end, and the second output end of the programmable modulator is respectively connected to the source of the first switch tube and the source of the second switch tube;

[0018] The drain of the first switch tube is connected to the first input terminal of the power transformer, and the gate of the first switch tube is connected to the second output terminal of the digital signal modulator;

[0019] The drain of the second switch tube is connected to the second input terminal of the power transformer, and the gate of the second switch tube is connected to the first output terminal of the digital signal modulator;

[0020] The source of the third switch tube is connected to the ground terminal, the drain of the third switch tube is connected to the second input terminal of the power transformer, and the gate of the third switch tube is connected to the first output terminal of the digital signal modulator;

[0021] The source of the fourth switch tube is connected to the ground terminal, the drain of the fourth switch tube is connected to the first input terminal of the power transformer, and the gate of the fourth switch tube is connected to the second output terminal of the digital signal modulator;

[0022] The first output end of the power transformer is connected to the first input end of the pressure sensor, and the second output end of the power transformer is connected to the second input end of the pressure sensor.

[0023] In yet another alternative, the programmable drive control circuit further includes a rectifier diode, wherein:

[0024] The anode of the rectifier diode is connected to the first output terminal of the power transformer, and the cathode of the rectifier diode is connected to the first input terminal of the pressure sensor.

[0025] In yet another optional solution, the programmable drive control circuit further includes a filter capacitor, wherein:

[0026] The first end of the filter capacitor is connected to the cathode of the rectifier diode and the first input end of the pressure sensor respectively, and the second end of the filter capacitor is connected to the second output end of the power transformer and the second input end of the pressure sensor respectively.

[0027] In another optional solution, the output end of the pressure sensor includes a first output end and a second output end, and the signal matching and amplification circuit includes an operational amplifier, a first resistor and a second resistor, wherein:

[0028] The first terminal of the operational amplifier is connected to the ground terminal, and a first resistor is connected between the first terminal of the operational amplifier and the ground terminal;

[0029] The second end of the operational amplifier is connected to the first output end of the pressure sensor, and a second resistor is connected between the second end of the operational amplifier and the first output end of the pressure sensor;

[0030] The third terminal of the operational amplifier is connected to the first output terminal of the first connector;

[0031] The fourth terminal of the operational amplifier is connected to the ground terminal;

[0032] The fifth terminal of the operational amplifier is connected to the analog-to-digital conversion circuit;

[0033] The second output terminal of the pressure sensor is connected to the ground terminal.

[0034] In yet another optional solution, the signal matching and amplifying circuit further includes a third resistor, wherein:

[0035] A first end of the third resistor is connected to the first end of the operational amplifier, and the other end of the third resistor is connected to the fifth end of the operational amplifier.

[0036] In another optional scheme, the first output end of the digital signal modulator outputs a high level signal within a preset first period and outputs a low level signal within a preset second period; the second output end of the digital signal modulator outputs a low level signal within the preset first period and outputs a high level signal within the preset second period.

[0037] Beneficial effects of this application:

[0038] The programmable digital modulation and drive circuit designed for the pressure sensor may include a microprocessor, a digital signal modulator, a programmable drive control circuit and an analog-to-digital conversion circuit. The overall structure is simple, the cost is low, and the operation is safe and reliable, wherein: the first output end of the microprocessor is connected to the input end of the digital signal modulator, the second output end of the microprocessor is connected to the first input end of the programmable drive control circuit, and the first input end of the microprocessor is connected to the output end of the analog-to-digital conversion circuit; the output end of the digital signal modulator is connected to the second input end of the programmable drive control circuit; the output end of the programmable drive control circuit is connected to the input end of the pressure sensor; and the first input end of the analog-to-digital conversion circuit is connected to the output end of the pressure sensor. A control signal is outputted by a microprocessor to a programmable drive control circuit, and the microprocessor controls a digital signal modulator to output an adjustable level signal to the programmable drive control circuit, so that the programmable drive control circuit outputs a drive signal corresponding to the control signal and the level signal to the pressure sensor, and then the analog-to-digital conversion circuit converts and processes the sampling signal outputted by the pressure sensor, and the analog-to-digital conversion circuit feeds back the converted sampling signal to the microprocessor. When the microprocessor detects that the sampling signal is too high or too low, the output control signal can be adjusted, so that the sampling signal subsequently outputted by the pressure sensor remains within a normal range. This can not only realize adaptive closed-loop adjustment and control of drive and sampling feedback, improve the anti-interference performance of the overall circuit, but also ensure the sampling detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 A schematic diagram of the structure of a programmable digital modulation and drive circuit of a pressure sensor provided in an embodiment of the present application;

[0041] Figure 2 A schematic diagram of the structure of a programmable digital modulation and drive circuit of another pressure sensor provided in an embodiment of the present application;

[0042] Figure 3 A schematic diagram of output terminal signals of a digital signal modulator provided in an embodiment of the present application;

[0043] Figure 4 A circuit effect diagram of a programmable digital modulation and drive circuit of a pressure sensor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0045] In the following introduction, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The following introduction provides multiple embodiments of the present application, and different embodiments can be replaced or combined, so the present application can also be considered to include all possible combinations of the same and / or different embodiments recorded. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present application should also be considered to include embodiments containing one or more of all other possible combinations of A, B, C, and D, although the embodiment may not be clearly recorded in the following text.

[0046] The following description provides examples and does not limit the scope, applicability or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements described without departing from the scope of the present application. Various processes or components may be appropriately omitted, substituted or added to each example. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted or combined. In addition, features described in some examples may be combined in other examples.

[0047] See also Figure 1 , Figure 1A schematic diagram of the structure of a programmable digital modulation and drive circuit of a pressure sensor provided in an embodiment of the present application is shown.

[0048] like Figure 1 As shown, the programmable digital modulation and driving circuit of the pressure sensor may include at least a microprocessor, a digital signal modulator, a programmable driving control circuit and an analog-to-digital conversion circuit, wherein:

[0049] The first output terminal of the microprocessor is connected to the input terminal of the digital signal modulator to output a level parameter instruction containing any frequency, phase, pulse width or duty cycle to the digital signal modulator, and corresponding level parameter instructions can be set for different types of pressure sensors to expand the application scope of the entire programmable digital modulation and drive circuit. Here, the programmable digital modulation and drive circuit mentioned in the embodiment of the present application can also include, but is not limited to, a digital signal processing unit (Digital Signal Processor, DSP), which can be arranged between the first output terminal of the microprocessor and the input terminal of the digital signal modulator, and is used to receive the level parameter instruction containing any frequency, phase, pulse width or duty cycle output by the microprocessor, so as to process the level parameter instruction according to a preset algorithm or control logic, and the processed level parameter instruction can be output to the digital signal modulator, so that the digital signal modulator can quickly modulate a level signal that meets any frequency, phase, pulse width or duty cycle requirements.

[0050] In addition, the second output terminal of the microprocessor is connected to the first input terminal of the programmable drive control circuit to output a control signal for generating a drive signal to the programmable drive control circuit, and corresponding control signals can be set for different types of pressure sensors to expand the application range of the entire programmable digital modulation and drive circuit; the first input terminal of the microprocessor is connected to the output terminal of the analog-to-digital conversion circuit to receive a sampling signal output by the analog-to-digital conversion circuit after analog-to-digital conversion processing.

[0051] The output end of the digital signal modulator is connected to the second input end of the programmable drive control circuit to output the modulated level signal that meets any frequency, phase, pulse width or duty cycle requirements to the programmable drive control circuit. Here, the digital signal modulator proposed in the embodiment of the present application is flexible and efficient in design, and can realize modulation of any frequency, phase, pulse width and duty cycle through preset software logic, greatly simplifying the hardware circuit implementation, thereby reducing power consumption and cost.

[0052] The output end of the programmable drive control circuit is connected to the input end of the pressure sensor to generate a corresponding drive signal (i.e., drive voltage) in combination with the control signal output by the microprocessor, and to modulate the drive signal according to the level signal output by the digital signal modulator, so that the modulated drive signal is consistent with any frequency, phase, pulse width or duty cycle corresponding to the level signal, and the modulated drive signal can be output to the pressure sensor. Here, the pressure sensor can be understood as a domestic semiconductor pressure sensor well known in the art, and the output end of the pressure sensor is connected to the first input end of the analog-to-digital conversion circuit to output a corresponding sampling signal (i.e., induced voltage) to the analog-to-digital conversion circuit when subjected to external pressure.

[0053] It can be understood that the microprocessor outputs a control signal to the programmable drive control circuit, and the microprocessor controls the digital signal modulator to output an adjustable level signal to the programmable drive control circuit, so that the programmable drive control circuit generates a drive signal that meets any frequency, phase, pulse width or duty cycle requirements according to the control signal and the modulated level signal, and outputs it to the pressure sensor; then, when the pressure sensor is subjected to external pressure, it can output a corresponding sampling signal to the analog-to-digital conversion circuit, so that the analog-to-digital conversion circuit converts and processes the sampling signal output by the pressure sensor, and the analog-to-digital conversion circuit feeds back the converted sampling signal to the microprocessor, and the output control signal can be adjusted when the microprocessor detects that the sampling signal is too high or too low, for example but not limited to when the microprocessor detects that the sampling signal is higher than the calibration value, the programmable drive control circuit can be controlled to reduce the amplitude of the generated drive signal, or the digital signal modulator can be controlled to reduce the amplitude of the generated level signal, so that the sampling signal subsequently output by the pressure sensor remains within a normal range, which can not only realize the adaptive closed-loop adjustment control of the drive and sampling feedback, improve the anti-interference performance of the overall circuit, but also ensure the sampling detection accuracy.

[0054] It should be noted that when the microprocessor detects that the sampling signal exceeds the set safety threshold value, it can also determine whether the set protection operating point is reached through the preset judgment logic, so that when it is determined that the set protection operating point is reached, a protection signal is output to the programmable drive control circuit, that is, the programmable drive control circuit is in a stopped operating state, thereby achieving overvoltage protection.

[0055] As an option of the embodiment of the present application, the programmable digital modulation and driving circuit further includes a signal matching and amplification circuit, wherein:

[0056] The first input end of the signal matching and amplifying circuit is connected to the output end of the pressure sensor, and the output end of the signal matching and amplifying circuit is connected to the first input end of the analog-to-digital conversion circuit, so as to perform shaping and amplifying processing on the sampling signal output by the pressure sensor to avoid the sampling signal being interfered by external high and low frequency signals, and the sampling signal after amplification processing can be output to the analog-to-digital conversion circuit to ensure the effectiveness and reliability of the signal conversion performed by the analog-to-digital conversion circuit.

[0057] It should be noted that when the signal matching and amplifying circuit detects that the sampling signal output by the pressure sensor exceeds the preset sampling threshold, the signal matching and amplifying circuit can also but is not limited to automatically switch to a stop state to achieve overvoltage protection without the need for additional protection circuits.

[0058] As another option of the embodiment of the present application, the programmable digital modulation and driving circuit further includes a first connector, wherein:

[0059] The first connector can be understood as a 4-core foolproof connector well known in the art. The input end of the first connector is connected to the power supply (or a lithium battery) to receive the power signal output by the power supply; the first output end of the first connector is respectively connected to the second input end of the microprocessor, the third input end of the programmable drive control circuit, the second input end of the analog-to-digital conversion circuit and the second input end of the signal matching and amplification circuit to output power signals to the microprocessor, the programmable drive control circuit, the analog-to-digital conversion circuit and the signal matching and amplification circuit, respectively, to ensure the normal operation of the microprocessor, the programmable drive control circuit, the analog-to-digital conversion circuit and the signal matching and amplification circuit; the second output end of the first connector is connected to the ground end.

[0060] As another option of the embodiment of the present application, the programmable digital modulation and driving circuit further includes a second connector, wherein:

[0061] The second connector can be understood as a 4-core fool-proof connector well known in the art. The first input end of the second connector is connected to the first output end of the first connector to receive the power signal output by the first connector, thereby ensuring the normal operation of the second connector; the second input end of the second connector is connected to the third output end of the microprocessor, and the first output end of the second connector is connected to the Internet of Things device to feed back the control instructions output by the microprocessor to the Internet of Things device, thereby realizing communication between the microprocessor and the Internet of Things device; the second output end of the second connector is connected to the ground end.

[0062] Also see here Figure 2 FIG. 1 is a schematic diagram showing a structure of a programmable digital modulation and driving circuit of another pressure sensor provided in an embodiment of the present application, such as Figure 2As shown, the programmable digital modulation and driving circuit may include a microprocessor, a digital signal modulator, a programmable driving control circuit, a signal matching and amplification circuit, an analog-to-digital conversion circuit, a first connector and a second connector. The specific connection method can refer to the above-mentioned multiple embodiments, but will not be elaborated here.

[0063] As another option of the embodiment of the present application, the output end of the digital signal modulator includes a first output end and a second output end, the input end of the pressure sensor includes a first input end and a second input end, and the programmable drive control circuit includes a programmable modulator, a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a power transformer, wherein:

[0064] The first input end of the programmable modulator is connected to the first output end of the first connector, the second input end of the programmable modulator is connected to the second output end of the microprocessor, the first output end of the programmable modulator is connected to the ground end, and the second output end of the programmable modulator is respectively connected to the source of the first switch tube and the source of the second switch tube;

[0065] The drain of the first switch tube is connected to the first input terminal of the power transformer, and the gate of the first switch tube is connected to the second output terminal of the digital signal modulator;

[0066] The drain of the second switch tube is connected to the second input terminal of the power transformer, and the gate of the second switch tube is connected to the first output terminal of the digital signal modulator;

[0067] The source of the third switch tube is connected to the ground terminal, the drain of the third switch tube is connected to the second input terminal of the power transformer, and the gate of the third switch tube is connected to the first output terminal of the digital signal modulator;

[0068] The source of the fourth switch tube is connected to the ground terminal, the drain of the fourth switch tube is connected to the first input terminal of the power transformer, and the gate of the fourth switch tube is connected to the second output terminal of the digital signal modulator;

[0069] The first output end of the power transformer is connected to the first input end of the pressure sensor, and the second output end of the power transformer is connected to the second input end of the pressure sensor.

[0070] Here, the first output terminal of the digital signal modulator can be, but is not limited to, periodically outputting high-level signals and low-level signals, for example, it can output a high-level signal in a preset first period, and output a low-level signal in a preset second period, and the preset first period and the preset second period can constitute a continuous period in time; the second output terminal of the digital signal modulator can be, but is not limited to, periodically outputting high-level signals and low-level signals, for example, it can output a low-level signal in a preset first period, and output a high-level signal in a preset second period, that is, in the same time period, the level signal output by the first output terminal of the digital signal modulator and the level signal output by the second output terminal are in a phase complementary relationship. Figure 3 The output terminal signal diagram of a digital signal modulator provided by an embodiment of the present application is shown in FIG. Figure 3 As shown, the level signal outputted by the first output terminal of the digital signal modulator may be a periodic rectangular wave level signal, and the level signal at the initial moment is a high level signal; the level signal outputted by the second output terminal of the digital signal modulator may be a periodic rectangular wave level signal, and the level signal at the initial moment is a low level signal. It can be seen that the frequency, phase, pulse width or duty cycle of the level signal outputted by the first output terminal of the digital signal modulator and the level signal outputted by the second output terminal are consistent.

[0071] In addition, the first switch tube, the second switch tube, the third switch tube and the fourth switch tube mentioned above can be field effect transistors well known in the art. When the first output end of the digital signal modulator outputs a high-level signal and the second output end outputs a low-level signal, the first switch tube and the third switch tube are in the on state, and the second switch tube and the fourth switch tube are in the off state; when the first output end of the digital signal modulator outputs a low-level signal and the second output end outputs a high-level signal, the first switch tube and the third switch tube are in the off state, and the second switch tube and the fourth switch tube are in the on state.

[0072] In addition, a primary winding coil is arranged between the first input terminal and the second input terminal of the power transformer mentioned above; the number of the first output terminal of the power transformer can be set to two, wherein a first secondary winding coil can be arranged between the first output terminal and the second output terminal of the power transformer, and a second secondary winding coil can be arranged between the second output terminal and the second output terminal of the power transformer, and the voltage ratio between the primary winding coil and the first secondary winding coil or the second secondary winding coil is proportional to the corresponding number of coil turns, so as to realize coupling and power amplification of the driving signal, and there is no need to lose the driving signal power, so as to more conveniently realize power drive.

[0073] As another option of the embodiment of the present application, the programmable drive control circuit further includes a rectifier diode, wherein:

[0074] The positive electrode of the rectifier diode is connected to the first output end of the power transformer, and the negative electrode of the rectifier diode is connected to the first input end of the pressure sensor, so as to rectify the driving signal obtained by coupling processing of the power transformer and output the rectified driving signal to the pressure sensor.

[0075] The programmable drive control circuit also includes a filter capacitor, wherein:

[0076] The first end of the filter capacitor is connected to the cathode of the rectifier diode and the first input end of the pressure sensor respectively, and the second end of the filter capacitor is connected to the second output end of the power transformer and the second input end of the pressure sensor respectively, so as to perform high-frequency filtering on the driving signal after rectification, and output the driving signal after high-frequency filtering to the pressure sensor.

[0077] As another option of the embodiment of the present application, the output end of the pressure sensor includes a first output end and a second output end, and the signal matching and amplification circuit includes an operational amplifier, a first resistor and a second resistor, wherein:

[0078] The first terminal of the operational amplifier is connected to the ground terminal, and a first resistor is connected between the first terminal of the operational amplifier and the ground terminal;

[0079] The second end of the operational amplifier is connected to the first output end of the pressure sensor, and a second resistor is connected between the second end of the operational amplifier and the first output end of the pressure sensor;

[0080] The third terminal of the operational amplifier is connected to the first output terminal of the first connector;

[0081] The fourth terminal of the operational amplifier is connected to the ground terminal;

[0082] The fifth terminal of the operational amplifier is connected to the analog-to-digital conversion circuit;

[0083] The second output terminal of the pressure sensor is connected to the ground terminal.

[0084] The signal matching and amplifying circuit further includes a third resistor, wherein:

[0085] A first end of the third resistor is connected to the first end of the operational amplifier, and the other end of the third resistor is connected to the fifth end of the operational amplifier.

[0086] Here, the operational amplifier, the first resistor, the second resistor and the third resistor can together form a common-mode amplifier, and the two input terminals of the operational amplifier are high impedance to ensure the amplification accuracy of the sampling signal and reduce static power consumption.

[0087] Here, you can also see Figure 4 FIG. 1 is a circuit effect diagram of a programmable digital modulation and driving circuit of a pressure sensor provided by an embodiment of the present application. Figure 4 As shown, the microprocessor corresponds to U1, and the first output terminal of the microprocessor is set inside U1 ( Figure 4 (not shown in the figure), the second output terminal of the microprocessor corresponds to the VG terminal of U1, the third output terminal of the microprocessor corresponds to the RXD terminal and the TXD terminal of U1, the first input terminal of the microprocessor corresponds to the SDA terminal and the SCL terminal of U1, the second input terminal of the microprocessor corresponds to the VCC terminal of U1, and the microprocessor can also be connected to the ground terminal.

[0088] The analog-to-digital conversion circuit corresponds to U2, the first input terminal of the analog-to-digital conversion circuit corresponds to the VIN+ terminal and the VIN- terminal of U2, the second input terminal of the analog-to-digital conversion circuit corresponds to the VDD terminal of U2, the output terminal of the analog-to-digital conversion circuit corresponds to the SDA terminal and the SCL terminal of U2, and the analog-to-digital conversion circuit can also be connected to the ground terminal.

[0089] The signal matching and amplification circuit includes an operational amplifier U3, a first resistor R1, a second resistor R2 and a third resistor R3. The first end of the operational amplifier corresponds to the 2nd end of U3, the second end of the operational amplifier corresponds to the 3rd end of U3, the third end of the operational amplifier corresponds to the 7th end of U3, the fourth end of the operational amplifier corresponds to the 4th end of U3, and the fifth end of the operational amplifier corresponds to the 6th end of U3.

[0090] The pressure sensor corresponds to U4, the first input terminal of the pressure sensor corresponds to the VDG+ terminal (or terminal 3) of U4, the second input terminal of the pressure sensor corresponds to the VDG- terminal (or terminal 4) of U4, the first output terminal of the pressure sensor corresponds to the VO+ terminal (or terminal 1) of U4, and the second output terminal of the pressure sensor corresponds to the VO- terminal (or terminal 2) of U4.

[0091] The programmable drive control circuit includes a programmable modulator U6, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a power transformer U5, rectifier diodes D3 and D4, and a filter capacitor C1. Among them, the first input end of the programmable modulator corresponds to the end 1 of U6, the second input end of the programmable modulator corresponds to the end 4 of U6, the first output end of the programmable modulator corresponds to the end 2 of U6, and the second output end of the programmable modulator corresponds to the end 3 of U6; the first input end of the power transformer corresponds to the end 1 of U5, the second input end of the power transformer corresponds to the end 2 of U5, the first output end of the power transformer corresponds to the end 3 and the end 5 of U5, the second output end of the power transformer corresponds to the end 4 of U5, and the primary winding coil N1 is between the end 1 and the end 2 of U5, the first secondary winding coil N2 is between the end 3 and the end 4 of U5, and the second secondary winding coil N3 is between the end 5 and the end 4 of U5.

[0092] The digital signal modulator corresponds to U7, the first output end of the digital signal modulator corresponds to the A end of U7, and the second output end of the digital signal modulator corresponds to the B end of U7.

[0093] The first connector corresponds to U8, and the input end of the first connector is connected to the power supply ( Figure 4 (not shown in the figure), the first output end of the first connector corresponds to the 1st and 2nd ends of U8, and the second output end of the first connector corresponds to the 3rd and 4th ends of U8.

[0094] The second connector corresponds to U9, the first input end of the second connector corresponds to end 1 of U9, the second input end of the second connector corresponds to ends 3 and 4 of U9, and the first output end of the second connector is connected to the IoT device ( Figure 4 (not shown in the figure), the second output end of the second connector corresponds to end 2 of U9.

[0095] It can be understood that, by outputting a control signal to the programmable modulator U6 through the microprocessor U1, the microprocessor U1 controls the A end of the digital signal modulator U7 to output an adjustable level signal to the second switch tube Q2 and the third switch tube Q3, and the B end to output an adjustable level signal to the first switch tube Q1 and the fourth switch tube Q4, so that the digital signal modulator U7 generates a corresponding drive signal according to the control signal. At this time, when the A end outputs a high level signal and the B end outputs a low level signal in the same time period, the first switch tube Q1 and the third switch tube Q3 are turned on, and the drive signal is applied to the 1 end of the power transformer U5, and is output to the pressure sensor U4 through the 3rd and 4th ends of the power transformer U5; when the A end outputs a low level signal and the B end outputs a high level signal in the same time period, the second switch tube Q2 and the fourth switch tube Q4 are turned on, and the drive signal is applied to the 2nd end of the power transformer U5, and is output to the pressure sensor U4 through the 5th and 4th ends of the power transformer U5.

[0096] Next, when the pressure sensor U4 is subjected to external pressure, it can output the corresponding sampling signal to the 3-terminal of the operational amplifier U3, so that the processed sampling signal can be output to the VIN+ terminal of the analog-to-digital conversion circuit U2 by the 6-terminal of the operational amplifier U3, and the converted sampling signal can be output to the SDA terminal and SCL terminal of the microprocessor U1 by the SDA terminal and SCL terminal of the analog-to-digital conversion circuit U2, and when the microprocessor U1 detects that the sampling signal is too high or too low, it adjusts the output control signal, so that the sampling signal subsequently output by the pressure sensor U4 remains within the normal range, which can not only realize the adaptive closed-loop adjustment control of the drive and sampling feedback, improve the anti-interference performance of the overall circuit, but also ensure the sampling detection accuracy.

Claims

1. A programmable digital modulation and driving circuit for a pressure sensor, characterized in that: The circuit includes a microprocessor, a digital signal modulator, a programmable drive control circuit and an analog-to-digital conversion circuit, wherein: The first output terminal of the microprocessor is connected to the input terminal of the digital signal modulator, the second output terminal of the microprocessor is connected to the first input terminal of the programmable drive control circuit, and the first input terminal of the microprocessor is connected to the output terminal of the analog-to-digital conversion circuit; The output terminal of the digital signal modulator is connected to the second input terminal of the programmable drive control circuit; The output end of the programmable drive control circuit is connected to the input end of the pressure sensor; The first input terminal of the analog-to-digital conversion circuit is connected to the output terminal of the pressure sensor; Wherein, the circuit also includes a signal matching and amplification circuit, wherein: The first input terminal of the signal matching and amplifying circuit is connected to the output terminal of the pressure sensor, and the output terminal of the signal matching and amplifying circuit is connected to the first input terminal of the analog-to-digital conversion circuit; Wherein, the circuit further comprises a first connector, wherein: The input end of the first connector is connected to a power supply, the first output end of the first connector is respectively connected to the second input end of the microprocessor, the third input end of the programmable drive control circuit, the second input end of the analog-to-digital conversion circuit, and the second input end of the signal matching and amplification circuit, and the second output end of the first connector is connected to a ground end; The output end of the digital signal modulator includes a first output end and a second output end, the input end of the pressure sensor includes a first input end and a second input end, and the programmable drive control circuit includes a programmable modulator, a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a power transformer, wherein: The first input end of the programmable modulator is connected to the first output end of the first connector, the second input end of the programmable modulator is connected to the second output end of the microprocessor, the first output end of the programmable modulator is connected to the ground end, and the second output end of the programmable modulator is respectively connected to the source of the first switch tube and the source of the second switch tube; The drain of the first switch tube is connected to the first input terminal of the power transformer, and the gate of the first switch tube is connected to the second output terminal of the digital signal modulator; The drain of the second switch tube is connected to the second input terminal of the power transformer, and the gate of the second switch tube is connected to the first output terminal of the digital signal modulator; The source of the third switch tube is connected to the ground terminal, the drain of the third switch tube is connected to the second input terminal of the power transformer, and the gate of the third switch tube is connected to the first output terminal of the digital signal modulator; The source of the fourth switch tube is connected to the ground terminal, the drain of the fourth switch tube is connected to the first input terminal of the power transformer, and the gate of the fourth switch tube is connected to the second output terminal of the digital signal modulator; The first output end of the power transformer is connected to the first input end of the pressure sensor, and the second output end of the power transformer is connected to the second input end of the pressure sensor.

2. The circuit according to claim 1, characterized in that The circuit further comprises a second connector, wherein: The first input end of the second connector is connected to the first output end of the first connector, the second input end of the second connector is connected to the third output end of the microprocessor, the first output end of the second connector is connected to the Internet of Things device, and the second output end of the second connector is connected to the ground end.

3. The circuit according to claim 1, characterized in that The programmable drive control circuit also includes a rectifier diode, wherein: The anode of the rectifier diode is connected to the first output terminal of the power transformer, and the cathode of the rectifier diode is connected to the first input terminal of the pressure sensor.

4. The circuit according to claim 3, characterized in that The programmable drive control circuit also includes a filter capacitor, wherein: The first end of the filter capacitor is connected to the cathode of the rectifier diode and the first input end of the pressure sensor respectively, and the second end of the filter capacitor is connected to the second output end of the power transformer and the second input end of the pressure sensor respectively.

5. The circuit according to claim 1, characterized in that The output end of the pressure sensor includes a first output end and a second output end, and the signal matching and amplifying circuit includes an operational amplifier, a first resistor and a second resistor, wherein: the first end of the operational amplifier is connected to the ground end, and the first resistor is connected between the first end of the operational amplifier and the ground end; The second end of the operational amplifier is connected to the first output end of the pressure sensor, and the second resistor is connected between the second end of the operational amplifier and the first output end of the pressure sensor; The third terminal of the operational amplifier is connected to the first output terminal of the first connector; The fourth terminal of the operational amplifier is connected to the ground terminal; The fifth terminal of the operational amplifier is connected to the analog-to-digital conversion circuit; The second output terminal of the pressure sensor is connected to the ground terminal.

6. The circuit according to claim 5, characterized in that The signal matching and amplifying circuit further includes a third resistor, wherein: A first end of the third resistor is connected to a first end of the operational amplifier, and another end of the third resistor is connected to a fifth end of the operational amplifier.

7. The circuit according to claim 1, characterized in that The first output end of the digital signal modulator outputs a high level signal in a preset first cycle, and outputs a low level signal in a preset second cycle; the second output end of the digital signal modulator outputs a low level signal in the preset first cycle, and the second output end of the digital signal modulator outputs a high level signal in the preset second cycle.

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