Anti-interference circuit, control method and pressure sensor based on pressure sensor

Abstract

The present invention discloses an anti-interference circuit based on a pressure sensor, a control method and a pressure sensor, and relates to the technical field of sensors. The anti-interference circuit based on the pressure sensor includes a voltage stabilizing circuit, a varistor bridge, a conditioning circuit and an isolation buffer circuit, wherein the voltage stabilizing circuit generates a stable output working voltage according to a power supply voltage, the conditioning circuit zeroes the varistor bridge according to the working voltage, the varistor bridge performs pressure detection according to the working voltage and generates a voltage to be processed, the conditioning circuit generates a conditioning voltage according to the voltage to be processed, the isolation buffer circuit generates a stable output detection voltage according to the working voltage and the conditioning voltage, so that a display module displays a pressure value, the voltage stabilizing circuit provides a stable working voltage, the conditioning circuit zeroes before pressure measurement, and then generates a conditioning voltage according to the voltage to be processed, the isolation buffer circuit generates a stable output detection voltage according to the working voltage and the conditioning voltage, avoids signal interference of unstable input and output voltages, and improves pressure measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to an anti-interference circuit, a control method and a pressure sensor based on a pressure sensor. Background Art

[0002] With the vigorous development of measurement technology, pressure sensors are widely used in various fields. It is particularly important for pressure sensors to achieve accurate measurement in industrial control or detection. However, there is inevitably a certain amount of signal interference when the pressure sensor is measuring. Pressure sensors generally have a specific working voltage. When the input voltage provided by the power supply is different from the working voltage, the output of the pressure sensor will be unstable. After the pressure sensor outputs the measurement voltage, if it does not meet the input voltage of the subsequent equipment, it will also cause a large output signal error.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The main purpose of the present invention is to provide an anti-interference circuit, a control method and a pressure sensor based on a pressure sensor, aiming to solve the technical problem of signal interference in the input and output voltages of the pressure sensor in the prior art.

[0005] To achieve the above object, the present invention provides an anti-interference circuit based on a pressure sensor, the anti-interference circuit based on the pressure sensor comprising: a voltage stabilizing circuit, a varistor bridge, a conditioning circuit and an isolation buffer circuit connected in sequence, wherein the working voltage output end of the voltage stabilizing circuit is also connected to the working voltage input end of the conditioning circuit and the working voltage input end of the isolation buffer circuit respectively;

[0006] The voltage stabilizing circuit is used to receive a power supply voltage, generate a stable output working voltage according to the power supply voltage, and output the working voltage to the conditioning circuit, the varistor bridge and the isolation buffer circuit respectively;

[0007] The conditioning circuit is used to receive the working voltage and perform zero adjustment on the varistor bridge according to the working voltage;

[0008] The varistor bridge is used to receive the working voltage, perform pressure detection according to the working voltage, generate a voltage to be processed, and output the voltage to be processed to the conditioning circuit;

[0009] The conditioning circuit is further used to receive the voltage to be processed, generate a conditioned voltage according to the voltage to be processed, and output the conditioned voltage to the isolation buffer circuit;

[0010] The isolation buffer circuit is used to receive the working voltage and the conditioning voltage, generate a stable output detection voltage according to the working voltage and the conditioning voltage, and output the detection voltage to the display module so that the display module displays the pressure value according to the detection voltage.

[0011] Optionally, a reference voltage source chip, a first resistor and a first capacitor;

[0012] The first end of the first resistor is connected to the voltage output end of the power supply, the second end of the first resistor is respectively connected to the first end of the first capacitor and the reference electrode of the reference voltage source chip, the anode of the reference voltage source chip is grounded, and the second end of the first capacitor is grounded.

[0013] Optionally, the voltage stabilizing circuit further includes a first amplifier, a second resistor and a third resistor;

[0014] The cathode of the reference voltage source chip is connected to the non-inverting input terminal of the first amplifier, the inverting input terminal of the first amplifier is respectively connected to the first end of the second resistor and the first end of the third resistor, the output terminal of the first amplifier is respectively connected to the second end of the second resistor and the first end of the varistor bridge, and the second end of the third resistor is grounded.

[0015] Optionally, the conditioning circuit includes a signal conditioning chip, a fourth resistor and a second capacitor;

[0016] The first end of the signal conditioning chip is connected to the second end of the varistor bridge, the second end and the seventh end of the signal conditioning chip are connected to the analog ground respectively, the third end of the signal conditioning chip is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the analog ground, the fourth end of the signal conditioning chip is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the analog ground, the fifth end of the signal conditioning chip is connected to the conditioning voltage input end of the isolation buffer circuit, the sixth end of the signal conditioning chip is connected to the working voltage output end of the voltage stabilizing circuit, and the eighth end of the signal conditioning chip is connected to the third end of the varistor bridge.

[0017] Optionally, the conditioning circuit further includes a zero adjustment resistor;

[0018] The first end of the zero adjustment resistor is connected to the working voltage output end of the voltage stabilizing circuit, and the second end of the zero adjustment resistor is connected to the eighth end of the signal conditioning chip.

[0019] Optionally, the isolation buffer circuit includes a photocoupler and a first diode;

[0020] The anode of the photocoupler is connected to the conditioned voltage output terminal of the conditioning circuit, the cathode of the photocoupler is grounded, the anode of the first diode is connected to the working voltage output terminal of the voltage stabilizing circuit, and the cathode of the first diode is connected to the collector of the photocoupler.

[0021] Optionally, the isolation buffer circuit further includes a first transistor, a second transistor, a fifth resistor and a sixth resistor;

[0022] The emitter of the photoelectric coupler is respectively connected to the emitter of the first transistor and the first end of the fifth resistor, the base of the first transistor is respectively connected to the second end of the fifth resistor and the emitter of the second transistor, the base of the second transistor is respectively connected to the collector of the first transistor and the first end of the sixth resistor, the collector of the second transistor is connected to the display module, and the second end of the sixth resistor is grounded.

[0023] Optionally, the anti-interference circuit based on the pressure sensor further includes a filtering circuit, and the filtering circuit includes a second amplifier, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a third capacitor and a fourth capacitor;

[0024] The detection voltage output end of the isolation buffer circuit is connected to the first end of the seventh resistor, the second end of the seventh resistor is respectively connected to the first end of the eighth resistor and the first end of the third capacitor, the second end of the seventh resistor is also connected to the first end of the fourth capacitor, the second end of the fourth capacitor is grounded, the second end of the third capacitor is respectively connected to the in-phase input end of the second amplifier and the first end of the ninth resistor, the in-phase input end of the second amplifier is respectively connected to the first end of the tenth resistor and the first end of the eleventh resistor, the second end of the ninth resistor and the second end of the tenth resistor are respectively grounded, and the output end of the second amplifier is respectively connected to the second end of the eighth resistor and the second end of the eleventh resistor.

[0025] In addition, to achieve the above-mentioned purpose, the present invention also provides an anti-interference control method based on a pressure sensor, the anti-interference control method based on a pressure sensor is applied to the anti-interference circuit based on the pressure sensor, the anti-interference circuit based on the pressure sensor includes a voltage stabilizing circuit, a varistor bridge, a conditioning circuit and an isolation buffer circuit;

[0026] The anti-interference control method based on the pressure sensor includes:

[0027] The voltage stabilizing circuit receives a power supply voltage, generates a stable output working voltage according to the power supply voltage, and outputs the working voltage to the conditioning circuit, the varistor bridge and the isolation buffer circuit respectively;

[0028] The conditioning circuit receives the working voltage and performs zero adjustment on the varistor bridge according to the working voltage;

[0029] The varistor receives the working voltage, performs pressure detection according to the working voltage, generates a voltage to be processed, and outputs the voltage to be processed to the conditioning circuit;

[0030] The conditioning circuit receives the voltage to be processed, generates a conditioned voltage according to the voltage to be processed, and outputs the conditioned voltage to the isolation buffer circuit;

[0031] The isolation buffer circuit receives the operating voltage and the conditioning voltage, generates a stable output detection voltage according to the operating voltage and the conditioning voltage, and outputs the detection voltage to a display module, so that the display module displays a pressure value according to the detection voltage.

[0032] In addition, to achieve the above-mentioned purpose, the present invention further provides a pressure sensor, which includes the anti-interference circuit based on the pressure sensor or the anti-interference control method based on the pressure sensor as described above.

[0033] The present invention proposes an anti-interference circuit based on a pressure sensor. The anti-interference circuit based on the pressure sensor includes a voltage stabilizing circuit, a varistor bridge, a conditioning circuit and an isolation buffer circuit connected in sequence, wherein the working voltage output end of the voltage stabilizing circuit is also respectively connected to the working voltage input end of the conditioning circuit and the working voltage input end of the isolation buffer circuit. The present invention receives a power supply voltage through a voltage stabilizing circuit, generates a stably output working voltage according to the power supply voltage, and outputs the working voltage to the conditioned circuit, the varistor bridge and the isolation buffer circuit respectively. The conditioning circuit receives the working voltage, zeroes the varistor bridge according to the working voltage, the varistor bridge receives the working voltage, performs pressure detection according to the working voltage, and generates a voltage to be processed, and outputs the voltage to be processed to the conditioning circuit. The conditioning circuit receives the voltage to be processed, generates a conditioning voltage according to the voltage to be processed, and outputs the conditioning voltage to the isolation buffer circuit. The isolation buffer circuit receives the working voltage and the conditioning voltage. A detection voltage with a stable output is generated according to the working voltage and the conditioning voltage, and the detection voltage is output to the display module so that the display module displays the pressure value according to the detection voltage. The voltage stabilizing circuit provides a stable working voltage to the conditioning circuit, the varistor bridge and the isolation buffer circuit. The conditioning circuit is zeroed before the varistor bridge measures the pressure. The conditioning circuit generates a conditioning voltage according to the voltage to be processed output by the varistor bridge. The isolation buffer circuit generates a detection voltage with a stable output according to the working voltage and the conditioning voltage, thereby avoiding signal interference caused by unstable input and output voltages of the pressure sensor and improving the measurement accuracy of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0035] Figure 1 It is a structural schematic diagram of a first embodiment of an anti-interference circuit based on a pressure sensor of the present invention;

[0036] Figure 2 It is a structural schematic diagram of a second embodiment of an anti-interference circuit based on a pressure sensor of the present invention;

[0037] Figure 3 A circuit diagram of an embodiment of an anti-interference circuit based on a pressure sensor of the present invention;

[0038] Figure 4 It is a flow chart of an embodiment of an anti-interference control method based on a pressure sensor of the present invention.

[0039] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

[0040] Description of Figure Numbers:

[0041] Label name Label name 100 Voltage stabilization circuit C1~C4 The first to fourth capacitors 200 Varistor bridge R1~R11 The first to eleventh resistors 300 Conditioning circuit A1~A2 First to second amplifier 400 Isolation buffer circuit Q1~Q2 The first and second transistors 500 Filter circuit T1 Signal conditioning chip VIn Voltage input terminal L1 Voltage reference chip VOut Voltage output E1 Optocoupler RP Zero adjustment resistor D1 The first diode DETAILED DESCRIPTION

[0042] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0045] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0046] It is worth noting that in the actual application of the present invention, software programs will inevitably be applied, but the applicant hereby declares that the software programs used in the specific implementation of the technical solution are all prior art. In this application, it does not involve the modification and protection of software programs, but only the protection of the hardware architecture designed to achieve the purpose of the invention.

[0047] The present invention proposes an anti-interference circuit based on a pressure sensor, referring to Figure 1 , Figure 1 It is a structural schematic diagram of the first embodiment of the anti-interference circuit based on the pressure sensor of the present invention.

[0048] The anti-interference circuit based on the pressure sensor includes a voltage stabilizing circuit 100, a varistor bridge 200, a conditioning circuit 300 and an isolation buffer circuit 400 which are connected in sequence, wherein the working voltage output end of the voltage stabilizing circuit 100 is also respectively connected to the working voltage input end of the conditioning circuit 300 and the working voltage input end of the isolation buffer circuit 400.

[0049] The voltage stabilizing circuit 100 is used to receive a power supply voltage, generate a stable output working voltage according to the power supply voltage, and output the working voltage to the conditioning circuit 300, the varistor bridge 200 and the isolation buffer circuit 400 respectively.

[0050] It should be noted that the working voltage of the measurement system is easily affected by factors such as the environment and power supply ripple. Especially in the process of measuring component detection, surges caused by excessive input voltage can easily cause circuit damage, while too little pressure is insufficient to provide normal working voltage. Fluctuations in input voltage can easily cause nonlinear fluctuations in the detection value, which are difficult to compensate for with subsequent adjustments.

[0051] It is easy to understand that the voltage stabilizing circuit 100 receives the power supply voltage output by the power supply, and can first stabilize and regulate the power supply voltage to generate a regulated voltage with a stable output, and then amplify the regulated voltage to obtain an operating voltage that can be safely operated by subsequent equipment. The regulated voltage can be lower than the operating voltage of the subsequent equipment and within the subsequent amplification range, so that the power supply voltage is converted into a stable output operating voltage after regulation and amplification. This embodiment is not limited to this.

[0052] It is understandable that when the input voltage of the reference voltage source is close to the output voltage, the accuracy of the output voltage will decrease. The voltage stabilizing circuit 100 first regulates the power supply voltage to avoid a small voltage difference between the power supply voltage and the output voltage. The voltage difference can be amplified by voltage stabilizing regulation and then proportionally amplified to ensure a higher-precision operating voltage. This embodiment is not limited to this.

[0053] The conditioning circuit 300 is used to receive the working voltage and perform zero adjustment on the varistor bridge 200 according to the working voltage.

[0054] It is easy to understand that the pressure sensor needs to be conditioned before pressure detection to avoid excessive error in the pressure measurement result after the initial error is amplified. The conditioning circuit 300 is zeroed by setting the zero adjustment resistor RP. By changing the resistance value of the zero adjustment resistor RP, when the pressure sensor has no detected pressure, the displayed pressure value is zero, thereby avoiding zero-position interference of the pressure sensor.

[0055] The varistor bridge 200 is used to receive the working voltage, perform pressure detection according to the working voltage, generate a voltage to be processed, and output the voltage to be processed to the conditioning circuit 300 .

[0056] It should be noted that the varistor bridge 200 can be composed of four varistors with the same resistance value. In a specific implementation, the varistor bridge 200 can be a Wheatstone bridge used in a pressure sensor. When no pressure detection is performed, the varistor bridge 200 is in a balanced state. When subjected to pressure, the resistance value of the varistor changes, thereby generating a voltage to be processed. At this time, the voltage to be processed is small, and the voltage to be processed needs to be processed by the conditioning circuit 300, so as to obtain a detection voltage that can be recognized by subsequent devices.

[0057] The conditioning circuit 300 is further configured to receive the voltage to be processed, generate a conditioned voltage according to the voltage to be processed, and output the conditioned voltage to the isolation buffer circuit 400 .

[0058] It should be understood that the conditioning circuit 300 can amplify the voltage to be processed and use the compensation resistor to compensate for the gain error and temperature drift of the pressure sensor to condition the weak voltage output by the pressure sensor, thereby avoiding signal interference of the pressure sensor output voltage and improving the detection accuracy.

[0059] The isolation buffer circuit 400 is used to receive the working voltage and the conditioning voltage, generate a stable output detection voltage according to the working voltage and the conditioning voltage, and output the detection voltage to the display module so that the display module displays the pressure value according to the detection voltage.

[0060] It is easy to understand that when the varistor bridge 200 is subjected to a large pressure, a large conditioning voltage can be generated after conditioning by the conditioning circuit 300. If the conditioning voltage is directly output to the subsequent equipment, the subsequent equipment may be easily damaged by a large voltage shock. The isolation buffer circuit 400 utilizes the photoelectric effect to electrically isolate the detection part of the pressure sensor from other parts (such as a single-chip microcomputer, a display module, and an interface module, etc.), thereby reducing signal interference in the detection part and generating a safe and stable detection voltage.

[0061] In this embodiment, through the above circuit, the anti-interference circuit based on the pressure sensor includes a voltage stabilizing circuit 100, a varistor bridge 200, a conditioning circuit 300 and an isolation buffer circuit 400 connected in sequence, wherein the working voltage output end of the voltage stabilizing circuit 100 is also respectively connected to the working voltage input end of the conditioning circuit 300 and the working voltage input end of the isolation buffer circuit 400. The present invention receives the power supply voltage through the voltage stabilizing circuit 100, generates a stable output working voltage according to the power supply voltage, and outputs the working voltage to the conditioning circuit 300, the varistor bridge 200 and the isolation buffer circuit 400 respectively. The conditioning circuit 300 receives the working voltage and zeroes the varistor bridge 200 according to the working voltage. The varistor bridge 200 receives the working voltage, performs pressure detection according to the working voltage, and generates a voltage to be processed, and outputs the voltage to be processed to the conditioning circuit 300. The conditioning circuit 300 receives the voltage to be processed, generates a conditioning voltage according to the voltage to be processed, and outputs the conditioning voltage to the isolation buffer circuit 400. The isolation buffer circuit 400 receives the working voltage and the conditioning circuit 300. Voltage, a detection voltage with a stable output is generated according to the working voltage and the conditioning voltage, and the detection voltage is output to the display module so that the display module displays the pressure value according to the detection voltage. The voltage stabilizing circuit 100 provides a stable working voltage to the conditioning circuit 300, the varistor bridge 200 and the isolation buffer circuit 400. The conditioning circuit 300 performs zero adjustment before the varistor bridge 200 measures the pressure. The conditioning circuit 300 generates a conditioning voltage according to the voltage to be processed output by the varistor bridge 200. The isolation buffer circuit 400 generates a detection voltage with a stable output according to the working voltage and the conditioning voltage, thereby avoiding signal interference caused by unstable input and output voltages of the pressure sensor and improving the measurement accuracy of the sensor.

[0062] Based on the first embodiment of the present invention, a second embodiment of the anti-interference circuit based on the pressure sensor of the present invention is proposed, referring to Figure 2 , Figure 2 FIG. 1 is a schematic diagram of the structure of the second embodiment of the anti-interference circuit based on the pressure sensor of the present invention; Figure 3 , Figure 3 FIG. 4 is a circuit diagram of a second embodiment of the present invention.

[0063] In the second embodiment, the voltage stabilizing circuit 100 includes a reference voltage source chip L1 , a first resistor R1 , and a first capacitor C1 .

[0064] The first end of the first resistor R1 is connected to the voltage output end of the power supply, the second end of the first resistor R1 is respectively connected to the first end of the first capacitor C1 and the reference electrode of the reference voltage source chip L1, the anode of the reference voltage source chip L1 is grounded, and the second end of the first capacitor C1 is grounded.

[0065] It should be understood that the reference voltage source chip L1 has the advantages of reducing noise and high stability. The reference voltage source chip L1 receives the power supply voltage output by the power supply, and can regulate the power supply voltage to generate a stable output regulated voltage. Figure 3 The first end of the first resistor R1 can be a voltage input terminal VIn of an anti-interference circuit based on a pressure sensor. The first resistor R1 can divide the power supply voltage and output the divided voltage to the reference voltage source chip L1, thereby protecting the reference voltage source chip L1 to avoid the reference voltage source chip L1 being damaged by a large voltage shock when the power supply output pressure is too large. This embodiment is not limited to this.

[0066] In this embodiment, the voltage stabilizing circuit 100 further includes a first amplifier A1, a second resistor R2 and a third resistor R3;

[0067] The cathode of the reference voltage source chip L1 is connected to the non-inverting input terminal of the first amplifier A1, the inverting input terminal of the first amplifier A1 is respectively connected to the first end of the second resistor R2 and the first end of the third resistor R3, the output terminal of the first amplifier A1 is respectively connected to the second end of the second resistor R2 and the first end of the varistor bridge 200, and the second end of the third resistor R3 is grounded.

[0068] It should be noted that the first amplifier A1, the second resistor R2 and the third resistor R3 can form an amplifier circuit, and the non-inverting input terminal of the first amplifier A1 receives the voltage stably output by the reference voltage source chip L1, and amplifies the voltage, thereby avoiding the situation where the voltage difference between the power supply voltage and the input voltage of the varistor bridge 200 is small. The voltage difference can be amplified by the reference voltage source chip L1, and then proportionally amplified by the amplifier circuit composed of the first amplifier A1, the second resistor R2 and the third resistor R3 to ensure a high-precision working voltage. This embodiment is not limited to this.

[0069] In this embodiment, the conditioning circuit 300 includes a signal conditioning chip T1, a fourth resistor R4 and a second capacitor C2;

[0070] The first end of the signal conditioning chip T1 is connected to the second end of the varistor bridge 200, the second end and the seventh end of the signal conditioning chip T1 are respectively connected to the analog ground, the third end of the signal conditioning chip T1 is connected to the first end of the second capacitor C2, the second end of the second capacitor C2 is connected to the analog ground, the fourth end of the signal conditioning chip T1 is connected to the first end of the fourth resistor R4, the second end of the fourth resistor R4 is connected to the analog ground, the fifth end of the signal conditioning chip T1 is connected to the conditioned voltage input end of the isolation buffer circuit 400, the sixth end of the signal conditioning chip T1 is connected to the working voltage output end of the voltage stabilizing circuit 100, and the eighth end of the signal conditioning chip T1 is connected to the third end of the varistor bridge 200.

[0071] It should be noted that the signal conditioning chip T1 can amplify the voltage to be processed, the fourth resistor R4 can be the compensation resistor of the conditioning circuit 300, the signal conditioning chip T1 uses the compensation resistor to compensate for the gain error and temperature drift of the pressure sensor, the second capacitor C2 can be the filter capacitor of the conditioning circuit 300, the second capacitor C2 can minimize the influence of radio frequency interference in the voltage signal, so as to condition the weak voltage output by the pressure sensor, thereby avoiding signal interference of the output voltage of the pressure sensor and improving the detection accuracy. This embodiment is not limited to this.

[0072] In this embodiment, the conditioning circuit 300 further includes a zero adjustment resistor RP, a first end of the zero adjustment resistor RP is connected to the working voltage output end of the voltage stabilizing circuit 100, and a second end of the zero adjustment resistor RP is connected to the eighth end of the signal conditioning chip T1.

[0073] It is understandable that the pressure sensor needs to be conditioned before pressure detection to avoid excessive error in the pressure measurement result after the initial error is amplified. The zero-adjustment resistor RP can change its own resistance value so that when the pressure sensor has no detected pressure, the displayed pressure value is zero. Subsequent measurements can be performed only after the resistance value of the zero-adjustment resistor RP is determined, thereby avoiding zero-position interference of the pressure sensor. This embodiment is not limited to this.

[0074] In this embodiment, the isolation buffer circuit 400 includes a photocoupler E1 and a first diode D1;

[0075] The anode of the photocoupler E1 is connected to the conditioned voltage output terminal of the conditioning circuit 300, the cathode of the photocoupler E1 is grounded, the anode of the first diode D1 is connected to the working voltage output terminal of the voltage stabilizing circuit 100, and the cathode of the first diode D1 is connected to the collector of the photocoupler E1.

[0076] It should be understood that when the varistor bridge 200 is subjected to a large pressure, a large conditioning voltage can be generated after conditioning by the conditioning circuit 300. If the conditioning voltage is directly output to the subsequent equipment, the subsequent equipment may be easily damaged by a large voltage shock. The photoelectric coupler E1 utilizes the photoelectric effect to electrically isolate the detection part of the pressure sensor from other parts (such as a single-chip microcomputer, a display module, and an interface module, etc.), thereby reducing signal interference in the detection part and generating a safe and stable detection voltage. This embodiment does not impose any restrictions on this.

[0077] It is easy to understand that the cathode of the first diode D1 is connected to the collector of the transistor in the photocoupler E1, and the first diode D1 has unidirectional conductivity and voltage stabilizing rectification, which can stably output the working voltage of the voltage stabilizing circuit 100 to the photocoupler E1, and prevent the voltage interference signal generated by the photocoupler E1 from being fed back to the varistor bridge 200 and the conditioning circuit 300. This embodiment is not limited to this.

[0078] In this embodiment, the isolation buffer circuit 400 further includes a first transistor Q1, a second transistor Q2, a fifth resistor R5 and a sixth resistor R6;

[0079] The emitter of the photoelectric coupler E1 is respectively connected to the emitter of the first transistor Q1 and the first end of the fifth resistor R5, the base of the first transistor Q1 is respectively connected to the second end of the fifth resistor R5 and the emitter of the second transistor Q2, the base of the second transistor Q2 is respectively connected to the collector of the first transistor Q1 and the first end of the sixth resistor R6, the collector of the second transistor Q2 is connected to the display module, and the second end of the sixth resistor R6 is grounded.

[0080] It should be noted that the circuit composed of the first transistor Q1 and the second transistor Q2 can have a buffering effect. When the photocoupler E1 outputs a voltage to the emitter of the first transistor Q1, the base voltage of the first transistor Q1 is less than the emitter voltage of the first transistor Q1, the first transistor Q1 is turned on, and the emitter voltage of the second transistor Q2 is greater than the base voltage of the second transistor Q2, the second transistor Q2 is turned on, thereby stabilizing the output detection voltage. This embodiment is not limited to this.

[0081] It can be understood that the fifth resistor R5 can be a bias resistor of the first transistor Q1, which can provide a bias voltage for the emitter of the first transistor Q1, and the sixth resistor R6 can be a bias resistor of the second transistor Q2, which can provide a bias voltage for the emitter of the second transistor Q2. This embodiment is not limited to this.

[0082] In this embodiment, the anti-interference circuit based on the pressure sensor further includes a filter circuit 500, and the filter circuit 500 includes a second amplifier A2, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a third capacitor C3 and a fourth capacitor C4;

[0083] The detection voltage output end of the isolation buffer circuit 400 is connected to the first end of the seventh resistor R7, the second end of the seventh resistor R7 is respectively connected to the first end of the eighth resistor R8 and the first end of the third capacitor C3, the second end of the seventh resistor R7 is also connected to the first end of the fourth capacitor C4, the second end of the fourth capacitor C4 is grounded, the second end of the third capacitor C3 is respectively connected to the in-phase input end of the second amplifier A2 and the first end of the ninth resistor R9, the in-phase input end of the second amplifier A2 is respectively connected to the first end of the tenth resistor R10 and the first end of the eleventh resistor R11, the second end of the ninth resistor R9 and the second end of the tenth resistor R10 are respectively grounded, and the output end of the second amplifier A2 is respectively connected to the second end of the eighth resistor R8 and the second end of the eleventh resistor R11.

[0084] It is easy to understand that the second amplifier A2, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, the third capacitor C3 and the fourth capacitor C4 can form a second-order bandpass filter, which can further filter and amplify the detection voltage output by the isolation buffer circuit 400, thereby obtaining a detection voltage with higher measurement accuracy, such as Figure 3 The output end of the second amplifier A2 may also be a voltage output end VOut of an anti-interference circuit based on a pressure sensor, which is not limited in this embodiment.

[0085] The present invention adopts the above circuit, the voltage stabilizing circuit 100 includes a reference voltage source chip L1, a first resistor R1, a first capacitor C1, a first amplifier A1, a second resistor R2 and a third resistor R3, the conditioning circuit 300 includes a signal conditioning chip T1, a fourth resistor R4, a second capacitor C2 and a zero adjustment resistor RP, the isolation buffer circuit 400 includes a photocoupler E1, a first diode D1, a first transistor Q1, a second transistor Q2, a fifth resistor R5 and a sixth resistor R6, and the anti-interference circuit based on the pressure sensor also includes a filter circuit 500, and the filter circuit 500 includes a second amplifier A2, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, the third capacitor C3 and the fourth capacitor C4 generate a stable operating voltage through the reference voltage source chip L1 and the first amplifier A1, the zero adjustment resistor RP is zeroed before measurement, the signal conditioning chip T1 conditions and amplifies the voltage to be processed, the photoelectric coupler E1 isolates signal interference, the first transistor Q1 and the second transistor Q2 make the voltage output stable, thereby avoiding signal interference caused by unstable input and output voltages of the pressure sensor, and improving the measurement accuracy and detection accuracy of the sensor.

[0086] Further, refer to Figure 4 , Figure 4 The present invention is a flowchart of an embodiment of an anti-interference control method based on a pressure sensor, wherein the anti-interference control method based on a pressure sensor is applied to an anti-interference circuit based on a pressure sensor, wherein the anti-interference circuit based on the pressure sensor includes a voltage stabilizing circuit, a varistor bridge, a conditioning circuit and an isolation buffer circuit;

[0087] The anti-interference control method based on the pressure sensor includes:

[0088] Step S10: the voltage stabilizing circuit receives a power supply voltage, generates a stable output working voltage according to the power supply voltage, and outputs the working voltage to the conditioning circuit, the varistor bridge and the isolation buffer circuit respectively.

[0089] It should be noted that the working voltage of the measurement system is easily affected by factors such as the environment and power supply ripple. Especially in the process of measuring component detection, surges caused by excessive input voltage can easily cause circuit damage, while too little pressure is insufficient to provide normal working voltage. Fluctuations in input voltage can easily cause nonlinear fluctuations in the detection value, which are difficult to compensate for with subsequent adjustments.

[0090] It is easy to understand that the voltage stabilizing circuit receives the power supply voltage output by the power supply, and can first stabilize and regulate the power supply voltage to generate a regulated voltage with a stable output, and then amplify the regulated voltage to obtain a working voltage that can be used for safe operation of subsequent equipment. The regulated voltage can be lower than the working voltage of the subsequent equipment and within the subsequent amplification range, so that the power supply voltage is converted into a stable output working voltage after regulation and amplification. This embodiment is not limited to this.

[0091] It is understandable that when the input voltage of the reference voltage source is close to the output voltage, the accuracy of the output voltage will decrease. The voltage stabilization circuit first regulates the power supply voltage to avoid a small voltage difference between the power supply voltage and the output voltage. The voltage difference can be amplified by voltage stabilization and then proportionally amplified to ensure a higher-precision operating voltage. This embodiment is not limited to this.

[0092] Step S20: the conditioning circuit receives the operating voltage and performs zero adjustment on the varistor bridge according to the operating voltage.

[0093] It is easy to understand that the pressure sensor needs to be conditioned before pressure detection to avoid excessive error in the pressure measurement result after the initial error is amplified. The conditioning circuit is zeroed by setting a zero adjustment resistor. By changing the resistance of the zero adjustment resistor, the pressure sensor displays a pressure value of zero when there is no pressure detection, thereby avoiding zero-position interference of the pressure sensor.

[0094] Step S30: the varistor receives the working voltage, performs pressure detection according to the working voltage, generates a voltage to be processed, and outputs the voltage to be processed to the conditioning circuit.

[0095] It should be noted that the varistor bridge can be composed of four varistors with the same resistance value. In a specific implementation, the varistor bridge can be a Wheatstone bridge used in a pressure sensor. When no pressure detection is performed, the varistor bridge is in a balanced state. When pressure is applied, the resistance of the varistor changes, thereby generating a voltage to be processed. At this time, the voltage to be processed is small and needs to be processed by a conditioning circuit to obtain a detection voltage that can be recognized by subsequent devices.

[0096] Step S40: the conditioning circuit receives the voltage to be processed, generates a conditioned voltage according to the voltage to be processed, and outputs the conditioned voltage to the isolation buffer circuit.

[0097] It should be understood that the conditioning circuit can amplify the voltage to be processed and use the compensation resistor to compensate for the gain error and temperature drift of the pressure sensor to condition the weak voltage output by the pressure sensor, thereby avoiding signal interference of the pressure sensor output voltage and improving the detection accuracy.

[0098] Step S50: the isolation buffer circuit receives the operating voltage and the conditioning voltage, generates a stable output detection voltage according to the operating voltage and the conditioning voltage, and outputs the detection voltage to the display module, so that the display module displays the pressure value according to the detection voltage.

[0099] It is easy to understand that when the varistor bridge is subjected to greater pressure, a greater conditioning voltage can be generated after conditioning by the conditioning circuit. If the conditioning voltage is directly output to subsequent equipment, the subsequent equipment may be easily damaged by a large voltage shock. The isolation buffer circuit uses the photoelectric effect to electrically isolate the detection part of the pressure sensor from other parts (such as the microcontroller, display module, and interface module, etc.), thereby reducing signal interference in the detection part and generating a safe and stable detection voltage.

[0100] In this embodiment, through the above control method, the voltage stabilizing circuit receives the power supply voltage, generates a stable output working voltage according to the power supply voltage, and outputs the working voltage to the conditioning circuit, the varistor bridge and the isolation buffer circuit respectively; the conditioning circuit receives the working voltage, adjusts the varistor bridge to zero according to the working voltage, the varistor bridge receives the working voltage, performs pressure detection according to the working voltage, and generates a voltage to be processed, and outputs the voltage to be processed to the conditioning circuit; the conditioning circuit receives the voltage to be processed, generates a conditioned voltage according to the voltage to be processed, and outputs the conditioned voltage to the isolation buffer circuit; the isolation buffer circuit receives the working voltage and the conditioning circuit The processing voltage is processed, and a detection voltage with a stable output is generated according to the working voltage and the conditioning voltage. The detection voltage is output to the display module, so that the display module displays the pressure value according to the detection voltage. The voltage stabilizing circuit provides a stable working voltage to the conditioning circuit, the varistor bridge and the isolation buffer circuit. The conditioning circuit is zeroed before the varistor bridge measures the pressure. The conditioning circuit generates a conditioning voltage according to the voltage to be processed output by the varistor bridge. The isolation buffer circuit generates a detection voltage with a stable output according to the working voltage and the conditioning voltage, thereby avoiding signal interference caused by unstable input and output voltages of the pressure sensor and improving the measurement accuracy of the sensor.

[0101] In addition, to achieve the above-mentioned purpose, the present invention further proposes a pressure sensor, which includes the anti-interference circuit based on the pressure sensor or the anti-interference control method based on the pressure sensor as described above.

[0102] Since the pressure sensor adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0103] It should be understood that the above is only an example and does not constitute any limitation on the technical solution of the present invention. In specific applications, technicians in this field can make settings as needed, and the present invention does not limit this.

[0104] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of the present invention. In practical applications, technicians in this field can select part or all of them according to actual needs to achieve the purpose of the present embodiment, and no limitation is made here.

[0105] In addition, for technical details that are not described in detail in this embodiment, reference can be made to the anti-interference circuit based on the pressure sensor provided in any embodiment of the present invention, and will not be repeated here.

[0106] In addition, it should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0107] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0108] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An anti-interference circuit based on a pressure sensor, characterized in that: The anti-interference circuit based on the pressure sensor comprises a voltage stabilizing circuit, a varistor bridge, a conditioning circuit and an isolation buffer circuit connected in sequence, wherein the working voltage output end of the voltage stabilizing circuit is also connected to the working voltage input end of the conditioning circuit and the working voltage input end of the isolation buffer circuit respectively; The voltage stabilizing circuit is used to receive a power supply voltage, generate a stable output working voltage according to the power supply voltage, and output the working voltage to the conditioning circuit, the varistor bridge and the isolation buffer circuit respectively; The conditioning circuit is used to receive the working voltage and perform zero adjustment on the varistor bridge according to the working voltage; The varistor bridge is used to receive the working voltage, perform pressure detection according to the working voltage, generate a voltage to be processed, and output the voltage to be processed to the conditioning circuit; The conditioning circuit is further used to receive the voltage to be processed, generate a conditioned voltage according to the voltage to be processed, and output the conditioned voltage to the isolation buffer circuit; The isolation buffer circuit is used to receive the working voltage and the conditioning voltage, generate a stable output detection voltage according to the working voltage and the conditioning voltage, and output the detection voltage to the display module so that the display module displays the pressure value according to the detection voltage; The voltage stabilizing circuit includes a reference voltage source chip, a first resistor and a first capacitor; The first end of the first resistor is connected to the voltage output end of the power supply, the second end of the first resistor is respectively connected to the first end of the first capacitor and the reference electrode of the reference voltage source chip, the anode of the reference voltage source chip is grounded, and the second end of the first capacitor is grounded; The conditioning circuit includes a signal conditioning chip, a fourth resistor and a second capacitor; The first end of the signal conditioning chip is connected to the second end of the varistor bridge, the second end and the seventh end of the signal conditioning chip are connected to analog ground respectively, the third end of the signal conditioning chip is connected to the first end of the second capacitor, the second end of the second capacitor is connected to analog ground, the fourth end of the signal conditioning chip is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to analog ground, the fifth end of the signal conditioning chip is connected to the conditioning voltage input end of the isolation buffer circuit, the sixth end of the signal conditioning chip is connected to the working voltage output end of the voltage stabilizing circuit, and the eighth end of the signal conditioning chip is connected to the third end of the varistor bridge; The isolation buffer circuit includes a photocoupler and a first diode; The anode of the photocoupler is connected to the conditioned voltage output terminal of the conditioning circuit, the cathode of the photocoupler is grounded, the anode of the first diode is connected to the working voltage output terminal of the voltage stabilizing circuit, and the cathode of the first diode is connected to the collector of the photocoupler.

2. The anti-interference circuit based on the pressure sensor as claimed in claim 1, characterized in that: The voltage stabilizing circuit further includes a first amplifier, a second resistor and a third resistor; The cathode of the reference voltage source chip is connected to the non-inverting input terminal of the first amplifier, the inverting input terminal of the first amplifier is respectively connected to the first end of the second resistor and the first end of the third resistor, the output terminal of the first amplifier is respectively connected to the second end of the second resistor and the first end of the varistor bridge, and the second end of the third resistor is grounded.

3. The anti-interference circuit based on the pressure sensor as claimed in claim 1, characterized in that: The conditioning circuit also includes a zero adjustment resistor; The first end of the zero adjustment resistor is connected to the working voltage output end of the voltage stabilizing circuit, and the second end of the zero adjustment resistor is connected to the eighth end of the signal conditioning chip.

4. The anti-interference circuit based on the pressure sensor as claimed in claim 1, characterized in that: The isolation buffer circuit also includes a first triode, a second triode, a fifth resistor and a sixth resistor; The emitter of the photoelectric coupler is respectively connected to the emitter of the first transistor and the first end of the fifth resistor, the base of the first transistor is respectively connected to the second end of the fifth resistor and the emitter of the second transistor, the base of the second transistor is respectively connected to the collector of the first transistor and the first end of the sixth resistor, the collector of the second transistor is connected to the display module, and the second end of the sixth resistor is grounded.

5. The anti-interference circuit based on the pressure sensor according to any one of claims 1 to 4, characterized in that: The anti-interference circuit based on the pressure sensor further includes a filter circuit, and the filter circuit includes a second amplifier, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a third capacitor and a fourth capacitor; The detection voltage output end of the isolation buffer circuit is connected to the first end of the seventh resistor, the second end of the seventh resistor is respectively connected to the first end of the eighth resistor and the first end of the third capacitor, the second end of the seventh resistor is also connected to the first end of the fourth capacitor, the second end of the fourth capacitor is grounded, the second end of the third capacitor is respectively connected to the in-phase input end of the second amplifier and the first end of the ninth resistor, the in-phase input end of the second amplifier is respectively connected to the first end of the tenth resistor and the first end of the eleventh resistor, the second end of the ninth resistor and the second end of the tenth resistor are respectively grounded, and the output end of the second amplifier is respectively connected to the second end of the eighth resistor and the second end of the eleventh resistor.

6. An anti-interference control method based on a pressure sensor, characterized in that: The anti-interference control method based on the pressure sensor is applied to the anti-interference circuit based on the pressure sensor according to any one of claims 1 to 5, wherein the anti-interference circuit based on the pressure sensor comprises a voltage stabilizing circuit, a varistor bridge, a conditioning circuit and an isolation buffer circuit; The anti-interference control method based on the pressure sensor includes: The voltage stabilizing circuit receives a power supply voltage, generates a stable output working voltage according to the power supply voltage, and outputs the working voltage to the conditioning circuit, the varistor bridge and the isolation buffer circuit respectively; The conditioning circuit receives the working voltage and performs zero adjustment on the varistor bridge according to the working voltage; The varistor receives the working voltage, performs pressure detection according to the working voltage, generates a voltage to be processed, and outputs the voltage to be processed to the conditioning circuit; The conditioning circuit receives the voltage to be processed, generates a conditioned voltage according to the voltage to be processed, and outputs the conditioned voltage to the isolation buffer circuit; The isolation buffer circuit receives the operating voltage and the conditioning voltage, generates a stable output detection voltage according to the operating voltage and the conditioning voltage, and outputs the detection voltage to a display module, so that the display module displays a pressure value according to the detection voltage.

7. A pressure sensor, characterized in that: The pressure sensor comprises the anti-interference circuit based on the pressure sensor as claimed in any one of claims 1 to 5 or applies the anti-interference control method based on the pressure sensor as claimed in claim 6.

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