CN216770867U - Precision detection circuit of air pressure sensor - Google Patents
Precision detection circuit of air pressure sensor Download PDFInfo
- Publication number
- CN216770867U CN216770867U CN202122774754.0U CN202122774754U CN216770867U CN 216770867 U CN216770867 U CN 216770867U CN 202122774754 U CN202122774754 U CN 202122774754U CN 216770867 U CN216770867 U CN 216770867U
- Authority
- CN
- China
- Prior art keywords
- operational amplifier
- resistor
- input end
- pressure sensor
- air pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Measuring Fluid Pressure (AREA)
Abstract
The utility model discloses a precision detection circuit of an air pressure sensor, which comprises a constant current source unit, an error zero-setting unit and a differential amplification unit, wherein the constant current source unit comprises an operational amplifier U1C and the error zero-setting unit, the error zero-setting unit comprises a resistor Ra, a resistor Rb, a resistor Rc, a resistor Rd and an adjustable resistor VR1, the resistor Ra, the resistor Rb, the resistor Rc, the resistor Rd and the adjustable resistor VR1 are sequentially connected in series, a power supply VSS is connected with the reverse input end of the operational amplifier U1C after passing through the resistor R1, the forward input end of the operational amplifier U1C is grounded, the output end of the operational amplifier U1C is connected with the common end of the resistor Ra and the resistor Rd, the reverse input end of the operational amplifier U1C is connected with the common end of the resistor Rb and the resistor Rd, and the common end of the resistor Rc and the adjustable resistor VR1 are respectively used as the signal input end of the differential amplification unit. The utility model solves the problem of precise conditioning and amplification of the output signal of the air pressure sensor and ensures the accuracy of the output value and the detection value of the air pressure sensor.
Description
Technical Field
The utility model belongs to the technical field of detection of an air pressure sensor in an electrical stimulation therapeutic apparatus, and particularly relates to a precision detection circuit of the air pressure sensor.
Background
In the electrical stimulation therapeutic apparatus such as medium frequency, low frequency, interference electricity, etc., the real-time detection and control of the pressure in the electrode sucker is needed to ensure that the electrode sucker can be stably adsorbed on the surface of the skin of a human body, and the problem that the electrode sucker falls off in the electrical stimulation therapeutic process is avoided. The output of the existing air pressure sensor is weak, a corresponding signal conditioning circuit is generally needed, and the reliability of the signal conditioning circuit directly determines the accuracy of air pressure detection. The existing air pressure sensor signal conditioning circuit generally has large detection error, serious zero drift and complex zero drift adjustment.
Therefore, the precision detection circuit for the air pressure sensor has wide application value.
SUMMERY OF THE UTILITY MODEL
The utility model provides a precision detection circuit of an air pressure sensor, aiming at the problems in the precision conditioning and amplifying process of the output signal of the air pressure sensor at present. The accuracy of the output value and the detection value of the air pressure sensor is ensured.
The scheme adopted by the utility model for solving the technical problem is as follows: a precision detection circuit of an air pressure sensor comprises a constant current source unit, an error zero adjustment unit and a differential amplification unit, wherein the constant current source unit comprises an operational amplifier U1C and the error zero adjustment unit, the error zero adjustment unit comprises the air pressure sensor, a power supply VSS is connected with a reverse input end of the operational amplifier U1C after passing through a resistor R1, a forward input end of the operational amplifier U1C is grounded, an output end of the operational amplifier U1C is connected with a 2 nd pin of the air pressure sensor, a reverse input end of the operational amplifier U1C is connected with a 5 th pin of the air pressure sensor, a 3 rd pin of the air pressure sensor is used as a first signal input end of the differential amplification unit, a 1 st pin and a 6 th pin of the air pressure sensor are respectively connected with two ends of an adjustable resistor VR1, and an adjusting end of an adjustable resistor VR1 is respectively used as a second signal input end of the differential amplification unit; there are two loops, the first loop from the pressure sensor pin 2 to pin 3 to pin 5 to the inverting input of the operational amplifier U1C to the power supply VSS, and the second loop from the pressure sensor pin 2 to pin 1 to VR1 to pin 6 to pin 5 to the inverting input of the operational amplifier U1C to the power supply VSS.
Wherein the differential amplifying unit comprises an operational amplifier U1A, an operational amplifier U1B and an operational amplifier U1D, the common end of a resistor Rc and a resistor Rd is connected with the positive input end of the operational amplifier U1B, an adjusting end of the adjustable resistor VR1 is connected with a forward input end of the operational amplifier U1C, an inverting input end of the operational amplifier U1B is connected with an inverting input end of the operational amplifier U1D through a resistor R2, an inverting input end of the operational amplifier U1B and an output end thereof are connected with the resistor R3, an inverting input end of the operational amplifier U1D and an output end thereof are connected with a resistor R4, an output end of the operational amplifier U1B is connected with an inverting input end of the operational amplifier U1A through a resistor R5, an output end of the operational amplifier U1D is connected with a forward input end of the operational amplifier U1A through a resistor R6, an inverting input end and an output end of the operational amplifier U1A are connected with a resistor R7, and a forward input end of the operational amplifier U1A is grounded through a resistor R8.
The utility model has the beneficial effects that: the utility model solves the problem of precise conditioning and amplification of the output signal of the air pressure sensor and ensures the accuracy of the output value and the detection value of the air pressure sensor.
The special wiring mode of the operational amplifier U1C provides stable constant current for the sensor; the error zero setting unit can zero or appoint the voltage to the signal, can adjust the size of acquiescence output voltage, promotes the flexibility of circuit, can accurate calibration. The circuit formed by the four voltage stabilizing diodes can control the signal output to be 0-3.3V or a specified voltage range, and realize the voltage protection of the I/O port of the rear-end controller; the differential amplifying circuit composed of U1B, U1D and U1C can eliminate common-mode interference signals and effectively extract sensor information.
In the air pressure sensor precision detection circuit, in the constant current source unit, the operational amplifier provides stable constant current for the sensor, although the system comprises a variable resistor, VR1 is connected into the constant current part and is not changed, Rd is complementary with Rc, Ra is complementary with Rb, and the whole system is most stable. In the error zero setting unit of the constant current source unit, a novel sensor using method is adopted, VR1 is added to adjust the size of default output voltage, the flexibility of the circuit is improved, and accurate calibration can be realized. In the differential amplification unit, the sensor signal is effectively extracted by eliminating the common mode interference signal and is output from the PA 0.
Drawings
Fig. 1 is a circuit diagram of a precision detection circuit of an air pressure sensor.
Detailed Description
The utility model is further illustrated with reference to the following figures and examples.
A precision detection circuit of an air pressure sensor shown in figure 1 is used for solving the problem of precision conditioning and amplification of an output signal of the air pressure sensor and ensuring the accuracy of an output value and a detection value of the air pressure sensor. The circuit mainly comprises a constant current source unit 1, an error zero setting unit 2 and a differential amplification unit 3.
As can be seen in the figure, the constant current source unit 1 includes an operational amplifier U1C and an error zeroing unit 2,
the error zero setting unit comprises an air pressure sensor, a power supply VSS is connected with a reverse input end of an operational amplifier U1C after passing through a resistor R1, a forward input end of the operational amplifier U1C is grounded, an output end of the operational amplifier U1C is connected with a 2 nd pin of the air pressure sensor, a reverse input end of the operational amplifier U1C is connected with a 5 th pin of the air pressure sensor, a 3 rd pin of the air pressure sensor is used as a first signal input end of the differential amplification unit, a 1 st pin and a 6 th pin of the air pressure sensor are respectively connected with two ends of an adjustable resistor VR1, and an adjusting end of the adjustable resistor VR1 is respectively used as a second signal input end of the differential amplification unit. Specifically, the air pressure sensor comprises four piezoresistors Ra, Rb, Rc and Rd, wherein the resistance values of Ra and Rc are reduced along with the increase of pressure, and the resistance values of Rb and Rd are increased along with the increase of pressure. As can be seen, the piezoresistor Ra, the piezoresistor Rb, the piezoresistor Rc, the piezoresistor Rd and the adjustable resistor VR1 are connected in series in sequence. The power supply VSS is connected with the reverse input end of the operational amplifier U1C after passing through the voltage dependent resistor R1, the forward input end of the operational amplifier U1C is grounded, the output end of the operational amplifier U1C is connected with the common end of the voltage dependent resistor Ra and the voltage dependent resistor Rd, and the reverse input end of the operational amplifier U1C is connected with the common end of the voltage dependent resistor Rb and the voltage dependent resistor Rd. In the constant current source unit 1, the operational amplifier U1C supplies a stable constant current (I = VSS/R1) to the sensor, and although the system includes a variable resistor, the VR1 is connected to the constant current portion and is not changed, Rd is complementary to Rc, and Ra is complementary to Rb, so that the system is most stable as a whole.
In the error zero setting unit 2, a novel sensor using method is adopted, VR1 is added to adjust the size of default output voltage, the flexibility of the circuit is improved, and accurate calibration can be achieved.
Assuming that the air pressure is 10KPa, Ra = Rb = Rc = Rd.
In the first case: VR1 is in the middle position, the pin potential from the pressure sensor 3 is equal to the VR1 measurement end potential, and the differential output is 0;
when the air pressure is increased to 20KPa, the resistance values of Ra and Rc are reduced, and the resistance values of Rb and Rd are increased; at the moment, the potential of a pin 3 of the slave pressure sensor is less than the potential of a VR1 measuring end, and the voltage is output as a positive voltage 1V which can be sampled by a singlechip through the later stage differential amplification;
when the air pressure is reduced to 0KPa, the resistance values of Ra and Rc are increased, and the resistance values of Rb and Rd are reduced; at the moment, the potential of a pin 3 of the slave pressure sensor is greater than the potential of a VR1 measuring end, the output is negative voltage-1V through the subsequent differential amplification, and at the moment, the singlechip cannot normally sample and cannot obtain an air pressure value smaller than 10 KPa.
In the second case: by adjusting VR1, the output of the sliding rheostat is close to the Ra end, so that when the air pressure is 0KPa, the pin potential of the pressure sensor 3 is equal to the end potential measured by VR1, and the differential output is 0.
When the air pressure is 10KPa, the differential output is 1V;
when the air pressure is 20KPa, the differential output is 2V.
Therefore, the circuit can obtain the air pressure value above 0KPa, and the measurement range is expanded.
The special wiring mode of the operational amplifier U1C in the embodiment provides stable constant current for the sensor; among the prior art the gas sensor of the same type of product does not have the error zero set unit, belongs to the unique design of this embodiment, can zero or the appointed voltage to the signal, can adjust the size of acquiescence output voltage, and the flexibility of promotion circuit can accurate calibration.
The differential amplifying unit 3 comprises an operational amplifier U1A, an operational amplifier U1B and an operational amplifier U1D, wherein a second signal input end (the common end 3 of the pressure sensitive resistor Rc and the pressure sensitive resistor Rd) is connected with the positive input end of the operational amplifier U1B, a second signal input end (the adjusting end of the adjustable resistor VR 1) is connected with the positive input end of the operational amplifier U1D,
the inverting input end of the operational amplifier U1B is connected with the inverting input end of the operational amplifier U1D through a resistor R2, the inverting input end and the output end of the operational amplifier U1B are connected with a resistor R3, the inverting input end and the output end of the operational amplifier U1D are connected with the resistor R4, the output end of the operational amplifier U1B is connected with the inverting input end of the operational amplifier U1A through a resistor R5, the output end of the operational amplifier U1D is connected with the forward input end of the operational amplifier U1A through a resistor R6, the inverting input end and the output end of the operational amplifier U1A are connected with a resistor R7, and the forward input end of the operational amplifier U1A is grounded through a resistor R8.
In this embodiment the power supply VSS connected to 9 is a negative voltage, now 10 is higher than 9 and 8 outputs a positive voltage. After the operational amplifier U1C, there are two loops, the first one is via the barometric pressure sensor (2-3-5-9-Vss) and the other one is the barometric pressure sensor (2-1-VR 1-6-5-9-Vss); taking differential signals (3, 5) through the two loops; the operational amplifier U1B and the operational amplifier U1D are used as differential signal input ends (impedance is large), and the operational amplifier U1A is used for measuring the voltage difference between the two ends 7 and 14; the effect of R9 is to limit current, when the output end of U1A exceeds the 3.3V limit range, it clamps 3.3V through the D2-D3 loop, when the output end of U1A is less than 0V limit range, it clamps 0V through the D4-D1 loop.
The circuit formed by four voltage stabilizing diodes in the differential amplification unit 3 in the figure can control the signal output within 0-3.3V or a specified voltage range, and realize the voltage protection of the I/O port of the rear-end controller.
The differential amplifier circuit composed of the operational amplifiers U1B, U1D, and U1C in the differential amplifier unit 3 can eliminate common mode interference signals, effectively extract sensor information, and output the sensor information from the PA 0.
Claims (3)
1. A precision detection circuit of an air pressure sensor comprises a constant current source unit, an error zero setting unit and a differential amplification unit, and is characterized in that the constant current source unit comprises an operational amplifier U1C and the error zero setting unit, the error zero setting unit comprises the air pressure sensor, a power supply VSS is connected with a reverse input end of an operational amplifier U1C after passing through a resistor R1, a forward input end of the operational amplifier U1C is grounded, an output end of the operational amplifier U1C is connected with a 2 nd pin of the air pressure sensor, a reverse input end of the operational amplifier U1C is connected with a 5 th pin of the air pressure sensor, a 3 rd pin of the air pressure sensor is used as a first signal input end of the differential amplification unit, a 1 st pin and a 6 th pin of the air pressure sensor are respectively connected with two ends of an adjustable resistor VR1, and an adjustment end of an adjustable resistor 1 is respectively used as a second signal input end of the differential amplification unit; there are two loops, the first loop is from the 2 nd pin to the 3 rd pin to the 5 th pin of the pressure sensor to the inverting input of the operational amplifier U1C to the power supply VSS, and the second loop is from the 2 nd pin to the 1 st pin to the VR1 to the 6 th pin to the 5 th pin of the pressure sensor to the inverting input of the operational amplifier U1C to the power supply VSS.
2. The air pressure sensor precision detection circuit of claim 1, wherein the differential amplification unit comprises an operational amplifier U1A, an operational amplifier U1B and an operational amplifier U1D, the signal input end is connected with the positive input end of the operational amplifier U1B, the signal input end is connected with the positive input end of the operational amplifier U1D, the negative input end of the operational amplifier U1B is connected with the negative input end of the operational amplifier U1D through a resistor R2, the negative input end and the output end of the operational amplifier U1B are connected with a resistor R3, the negative input end and the output end of the operational amplifier U1D are connected with a resistor R4, the output end of the operational amplifier U1B is connected with the negative input end of the operational amplifier U1A through a resistor R5, the output end of the operational amplifier U1D is connected with the positive input end of the operational amplifier U1A through a resistor R6, the negative input end and the output end of the operational amplifier U1A is connected with a resistor R7, the positive input of operational amplifier U1A is connected to ground through resistor R8.
3. The air pressure sensor precision detection circuit of claim 1, wherein the air pressure sensor comprises four piezoresistors of a piezoresistor Ra, a piezoresistor Rb, a piezoresistor Rc and a piezoresistor Rd which are sequentially connected in series, wherein the resistance values of Ra and Rc decrease with the increase of pressure, and the resistance values of Rb and Rd increase with the increase of pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122774754.0U CN216770867U (en) | 2021-11-13 | 2021-11-13 | Precision detection circuit of air pressure sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122774754.0U CN216770867U (en) | 2021-11-13 | 2021-11-13 | Precision detection circuit of air pressure sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216770867U true CN216770867U (en) | 2022-06-17 |
Family
ID=81962520
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122774754.0U Active CN216770867U (en) | 2021-11-13 | 2021-11-13 | Precision detection circuit of air pressure sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216770867U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115628843A (en) * | 2022-11-10 | 2023-01-20 | 上海直川电子科技有限公司 | Pressure transmitter |
-
2021
- 2021-11-13 CN CN202122774754.0U patent/CN216770867U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115628843A (en) * | 2022-11-10 | 2023-01-20 | 上海直川电子科技有限公司 | Pressure transmitter |
| CN115628843B (en) * | 2022-11-10 | 2024-05-14 | 直川科技(上海)有限公司 | Pressure transmitter |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN204789958U (en) | Magneto resistive sensor operating circuit | |
| CN216770867U (en) | Precision detection circuit of air pressure sensor | |
| CN102539062A (en) | Sensor temperature drift compensation method and pressure sensor box | |
| CN102252700B (en) | Micro-cantilever beam piezoresistive bridge type sensor detecting instrument | |
| CN103257017A (en) | Compensation method for temperature drift of sensor | |
| CN103913610A (en) | Current sampling circuit with temperature drifting compensation function | |
| CN104165618A (en) | Apparatus for measuring height of aircraft, and method thereof | |
| CN110735699A (en) | controller for nitrogen oxide sensor | |
| CN103278290A (en) | Non-linear compensation circuit of pressure sensor | |
| CN113951859A (en) | Intracranial pressure sensor signal conditioning method | |
| CN203824695U (en) | Apparatus for inhibiting sensitivity thermal drift and noise of silicon nanowire giant piezoresistive sensor | |
| CN109520635B (en) | Platinum resistor nonlinear compensation and signal processing circuit | |
| CN205607567U (en) | Multrirange array pressure sensing chip and check out test set thereof | |
| CN203772910U (en) | Oscilloscope with constant temperature change amplitude | |
| CN101441236A (en) | Capacity sensor circuit based on Wien bridge and phase-locked loop | |
| CN203798845U (en) | Current sampling circuit with temperature drift compensation | |
| CN203241176U (en) | Non-linear compensating circuit of pressure sensor | |
| CN105043665B (en) | A kind of pressure detection system and its calibration method with automatic calibration function | |
| CN203642941U (en) | Multipath sensing single-channel constant current measuring device | |
| CN114325535A (en) | Temperature sampling method for direct current sensor | |
| CN209264037U (en) | Dual power supply digital-control amplifier circuit | |
| CN207622886U (en) | A kind of platinum resistance temperature signal conditioning circuit | |
| CN103869863A (en) | Sensor conditioning circuit | |
| CN205620054U (en) | Pressure becomes power transmission way | |
| CN219718187U (en) | Weak signal amplifier using sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |