CN112965566A - Temperature coefficient reduction circuit for zero-pressure differential output offset of high-precision pressure sensor - Google Patents
Temperature coefficient reduction circuit for zero-pressure differential output offset of high-precision pressure sensor Download PDFInfo
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- CN112965566A CN112965566A CN202110197452.3A CN202110197452A CN112965566A CN 112965566 A CN112965566 A CN 112965566A CN 202110197452 A CN202110197452 A CN 202110197452A CN 112965566 A CN112965566 A CN 112965566A
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- pressure sensor
- resistance value
- temperature coefficient
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
- G05F1/567—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for temperature compensation
Abstract
The invention discloses a temperature coefficient reduction circuit for zero-pressure differential output offset of a high-precision pressure sensor. The invention comprises the following steps: the temperature compensation circuit comprises a power supply VDD and a ground terminal GND, wherein a pull-up resistor R1 is connected to one end of the power supply VDD, a pull-down resistor R2 is connected to one end of the ground terminal GND, two resistors R3 and R4 which are connected in parallel and have the same resistance value are connected to the pull-down resistor R2, a differential output resistor Ra and a differential output resistor Rb which are connected in parallel are connected to the pull-up resistor R1, and a temperature compensation resistor is additionally arranged on a pressure sensor sheet, so that the temperature coefficient of the differential output imbalance of the circuit can be effectively adjusted, the influence of the temperature on the pressure sensor can be effectively reduced, the influence of the temperature on the differential output imbalance under the zero pressure condition of the sensor can be ignored, and the problems that the temperature coefficient of the differential output imbalance of the existing pressure sensor circuit cannot be adjusted and the influence.
Description
Technical Field
The invention relates to the technical field of analog chip design, in particular to a temperature coefficient reduction circuit for zero-pressure differential output maladjustment of a high-precision pressure sensor.
Background
With the rapid development of economy, the development of China in the aspects of new manufacturing technology is also rapidly promoted, and pressure sensors are indispensable in the fields of metering, automobiles, aerospace, household appliances and the like. The Pressure Sensor is manufactured by perfectly combining piezoresistive effect of monocrystalline silicon and micromachining technology, mainly adopts MEMS (Micro-Electro-Mechanical System) technology, common Pressure sensors comprise a Thick Film Resistance Pressure Sensor (Thick Film Resistance Pressure Sensor) and a Thin Film Resistance Pressure Sensor (Thin Film Resistance Pressure Sensor), and High Precision Pressure sensors (High Precision Pressure Sensor, HPPS) to be improved, the traditional Pressure Sensor is the combination of piezoresistive effect and Thin plate bending theory, the measuring method mainly uses the Wheatstone bridge principle, as shown in figure 1, the structure of the Pressure Sensor mainly comprises four piezoresistors R with the same Resistance value, the symmetrical two ends of the Pressure Sensor are respectively connected with a power supply and VDD, and the symmetrical two ends of the Pressure Sensor are connected with an output Vo + and Vo-. Under the condition of equilibrium, Vo + and Vo-are equal, when the two resistance values are increased under the action of stress, the voltage difference value between the two detection output ends can detect the pressure value through calculation, but the resistance value change is not only caused by pressure, but also caused by temperature, therefore, the influence of cross sensitivity on precision is not negligible, normally, the pressure sensor inputs a constant voltage source, the output signals are differential signals, the resistances of loads under the condition of zero pressure are equal, the output differential signals are also equal, only four resistors Ra, Rb, Rc and Rd diffused on a silicon chip are used for forming a Wheatstone bridge, under the condition of 40KPa pressure and 5V power voltage VDD, the temperature coefficient of differential output offset V _ offset under the condition of zero pressure is +/-1 mm Hg/DEG C, and a normalized temperature-offset diagram T-V _ offset diagram is shown in figure 2, it can be seen that the differential output offset of the pressure sensor manufactured by the scheme of fig. 1 is greatly influenced by the temperature under the condition of zero pressure.
Disclosure of Invention
The invention aims to provide a temperature coefficient reduction circuit for zero-pressure differential output offset of a high-precision pressure sensor, so as to solve the problems in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme: a temperature coefficient reduction circuit for zero pressure differential output offset of a high-precision pressure sensor comprises: the power supply comprises a power supply VDD and a ground terminal GND, wherein a pull-up resistor R1 is connected to one end of the power supply VDD, a pull-down resistor R2 is connected to one end of the ground terminal GND, two resistors R3 and R4 which are connected in parallel and have the same resistance value are connected to the pull-down resistor R2, two resistors Ra and Rb which are connected in parallel and output in a differential mode are connected to the pull-up resistor R1, a resistor Rc and a resistor Rd are connected to one ends of the resistors Ra and Rb respectively, one ends of the resistors Rc and Rd are connected to the resistor R3 and the resistor R4 respectively, the resistors Ra, the resistor Rb, the resistor Rc and the resistor Rd form a Wheatstone bridge, a voltage input end is connected to one ends of the resistors Ra and Rc, and one end.
Furthermore, the resistance value of the resistor R3 is 30-100 omega, and the resistance value of the resistor R4 is 30-100 omega.
Furthermore, the resistance value of the pull-up resistor R1 is 400-1400 omega, and the resistance value of the pull-down resistor R2 is 400-1400 omega.
Further, the resistance value of the resistor Ra is 240-320 omega, and the resistance value of the resistor Rb is 240-320 omega.
Further, the resistance value of the resistor Rc is 240 Ω -320 Ω, and the resistance value of the resistor Rd is 240 Ω -320 Ω.
Further, the temperature coefficient of the differential output offset is + -0.28 mm Hg/deg.C.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the temperature coefficient of differential output offset of the circuit can be effectively adjusted by adding the temperature compensation resistor outside the pressure sensor sheet, so that the influence of the temperature on the pressure sensor can be effectively reduced, the influence of the temperature on the differential output offset under the condition of zero pressure of the sensor can be ignored when the high-precision pressure sensor HPPS is used, and the problems that the temperature coefficient of the differential output offset of the existing pressure sensor circuit can not be adjusted, and the influence of the temperature on the pressure sensor is large are solved.
Drawings
FIG. 1 is a schematic diagram of a conventional uncompensated pressure sensor circuit;
FIG. 2 is a schematic diagram of the normalization of the temperature coefficient of the differential output offset for zero pressure with an uncompensated pressure sensor;
FIG. 3 is a schematic diagram of a temperature coefficient reduction circuit for zero pressure differential output offset of the high precision pressure sensor of the present invention;
FIG. 4 is a schematic diagram of the temperature coefficient normalization of the differential output offset under the zero pressure condition of the compensated high-precision pressure sensor according to the present invention;
fig. 5 is a schematic diagram of normalization of temperature coefficient of differential output maladjustment under the condition of zero pressure of an ideal state pressure sensor.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Referring to fig. 3-5, fig. 3 is a schematic diagram of a temperature coefficient reduction circuit for zero-pressure differential output offset of a high-precision pressure sensor according to the present invention; FIG. 4 is a schematic diagram of the temperature coefficient normalization of the differential output offset under the zero pressure condition of the compensated high-precision pressure sensor according to the present invention; fig. 5 is a schematic diagram of normalization of temperature coefficient of differential output offset under the condition of zero pressure of a pressure sensor in an ideal state, and a temperature coefficient reduction circuit of zero pressure differential output offset of a high-precision pressure sensor comprises: the power supply comprises a power supply VDD and a ground terminal GND, wherein a pull-up resistor R1 is connected to one end of the power supply VDD, a pull-down resistor R2 is connected to one end of the ground terminal GND, two resistors R3 and R4 which are connected in parallel and have the same resistance value are connected to the pull-down resistor R2, two resistors Ra and Rb which are connected in parallel and output in a differential mode are connected to the pull-up resistor R1, a resistor Rc and a resistor Rd are connected to one ends of the resistors Ra and Rb respectively, one ends of the resistors Rc and Rd are connected to the resistor R3 and the resistor R4 respectively, the resistors Ra, the resistor Rb, the resistor Rc and the resistor Rd form a Wheatstone bridge, a voltage input end is connected to one ends of the resistors Ra and Rc, and one end.
The resistance value of the resistor R3 is 30-100 omega, and the resistance value of the resistor R4 is 30-100 omega.
The resistance value of the pull-up resistor R1 is 400-1400 omega, and the resistance value of the pull-down resistor R2 is 400-1400 omega.
The resistance value of the resistor Ra is 240-320 omega, and the resistance value of the resistor Rb is 240-320 omega.
The resistance value of the resistor Rc is 240-320 omega, and the resistance value of the resistor Rd is 240-320 omega.
The temperature coefficient of the differential output offset is 0.28mm Hg/DEG C.
Example two
A temperature coefficient reduction circuit for zero pressure differential output offset of a high-precision pressure sensor comprises: the power supply comprises a power supply VDD and a ground terminal GND, wherein a pull-up resistor R1 is connected to one end of the power supply VDD, a pull-down resistor R2 is connected to one end of the ground terminal GND, two resistors R3 and R4 which are connected in parallel and have the same resistance value are connected to the pull-down resistor R2, two resistors Ra and Rb which are connected in parallel and output in a differential mode are connected to the pull-up resistor R1, a resistor Rc and a resistor Rd are connected to one ends of the resistors Ra and Rb respectively, one ends of the resistors Rc and Rd are connected to the resistor R3 and the resistor R4 respectively, the resistors Ra, the resistor Rb, the resistor Rc and the resistor Rd form a Wheatstone bridge, a voltage input end is connected to one ends of the resistors Ra and Rc, and one end.
The resistance value of the resistor R3 is 30 omega, and the resistance value of the resistor R4 is 30 omega.
The resistance value of the pull-up resistor R1 is 400 omega, and the resistance value of the pull-down resistor R2 is 400 omega.
The resistance value of the resistor Ra is 240 omega, and the resistance value of the resistor Rb is 240 omega.
The resistance value of the resistor Rc is 320 Ω, and the resistance value of the resistor Rd is 240 Ω.
EXAMPLE III
A temperature coefficient reduction circuit for zero pressure differential output offset of a high-precision pressure sensor comprises: the power supply comprises a power supply VDD and a ground terminal GND, wherein a pull-up resistor R1 is connected to one end of the power supply VDD, a pull-down resistor R2 is connected to one end of the ground terminal GND, two resistors R3 and R4 which are connected in parallel and have the same resistance value are connected to the pull-down resistor R2, two resistors Ra and Rb which are connected in parallel and output in a differential mode are connected to the pull-up resistor R1, a resistor Rc and a resistor Rd are connected to one ends of the resistors Ra and Rb respectively, one ends of the resistors Rc and Rd are connected to the resistor R3 and the resistor R4 respectively, the resistors Ra, the resistor Rb, the resistor Rc and the resistor Rd form a Wheatstone bridge, a voltage input end is connected to one ends of the resistors Ra and Rc, and one end.
The resistance value of the resistor R3 is 100 omega, and the resistance value of the resistor R4 is 100 omega.
The resistance value of the pull-up resistor R1 is 1400 omega, and the resistance value of the pull-down resistor R2 is 1400 omega.
The resistance value of the resistor Ra is 240 Ω, and the resistance value of the resistor Rb is 320 Ω.
The resistance value of the resistor Rc is 240 Ω, and the resistance value of the resistor Rd is 320 Ω.
The study of the temperature coefficient reduction circuit of the zero-pressure differential output offset of the high-precision pressure sensor:
in the pressure sensor circuit according to the first to third embodiments,
| examples | Differential output offset | Influence of temperature | Temperature coefficient of |
| Example one | Has low influence | Is low in | 0.28mm Hg/℃ |
| Example two | Has low influence | Is low in | 0.27mm Hg/℃ |
| EXAMPLE III | Has low influence | Is low in | 0.28mm Hg/℃ |
The result shows that the temperature coefficient reduction circuit for the zero-pressure differential output offset of the high-precision pressure sensor has low differential output offset influence and low temperature influence, and the temperature coefficient can reach less than or equal to 0.28mm Hg/DEG C.
In summary, the temperature coefficient reduction circuit for zero-pressure differential output offset of a high-precision pressure sensor according to the present invention is provided with a pull-up resistor R1 and a pull-down resistor R2 respectively connected to the power supply VDD and the ground GND, meanwhile, two resistors R3 and R4 which are connected in parallel and have the same resistance value are connected to the pull-down resistor and are finally respectively connected with two on-chip resistors at the lower end of the differential output, on the basis of the original Wheatstone bridge structure formed by on-chip resistors, under the condition that the resistance values of the resistors R3 and R4 are both 30-100 omega, and the resistance values of the resistor R1 and the resistor R2 are both 400-1400 omega, the differential output offset can be minimized by temperature under zero pressure condition of the pressure sensor, and the high-precision pressure sensor can be used for detecting the differential output offset under zero pressure condition, the temperature coefficient of the difference output offset can reach less than or equal to 0.28mm Hg/DEG C. In addition, the resistance value of the newly introduced four resistors R1-R4 outside the chip can be finely adjusted by using the laser resistance trimming machine, the accuracy of the sensor can be further calibrated, and the normalized T-V _ offset diagram is shown in fig. 4 after modification, and the sensor should be ideally not affected by temperature, the idealized normalized schematic diagram would be a straight line, as shown in fig. 5, so the zero-pressure differential output offset temperature coefficient reduction circuit of the present invention can optimize the normalized T-V _ offset correlation to be closer to the ideal result, by adding a temperature compensated resistor to the pressure sensor chip, can effectively adjust the temperature coefficient of the difference output offset of the circuit, so that the influence of the temperature on the pressure sensor can be effectively reduced, thus, when using a high accuracy pressure sensor HPPS, the effect of temperature on differential output offset at zero sensor pressure can be neglected.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. A temperature coefficient reduction circuit for zero pressure differential output offset of a high-precision pressure sensor is characterized by comprising: the power supply comprises a power supply VDD and a ground terminal GND, wherein a pull-up resistor R1 is connected to one end of the power supply VDD, a pull-down resistor R2 is connected to one end of the ground terminal GND, two resistors R3 and R4 which are connected in parallel and have the same resistance value are connected to the pull-down resistor R2, two resistors Ra and Rb which are connected in parallel and output in a differential mode are connected to the pull-up resistor R1, a resistor Rc and a resistor Rd are connected to one ends of the resistors Ra and Rb respectively, one ends of the resistors Rc and Rd are connected to the resistor R3 and the resistor R4 respectively, the resistors Ra, the resistor Rb, the resistor Rc and the resistor Rd form a Wheatstone bridge, a voltage input end is connected to one ends of the resistors Ra and Rc, and one end.
2. The zero-pressure differential output offset temperature coefficient reduction circuit of a high-precision pressure sensor as claimed in claim 1, wherein the resistance value of the resistor R3 is 30 Ω -100 Ω, and the resistance value of the resistor R4 is 30 Ω -100 Ω.
3. The zero-pressure differential output offset temperature coefficient reduction circuit of a high-precision pressure sensor as claimed in claim 1, wherein the resistance value of the pull-up resistor R1 is 400 Ω -1400 Ω, and the resistance value of the pull-down resistor R2 is 400 Ω -1400 Ω.
4. The zero-pressure differential output offset temperature coefficient reduction circuit for a high precision pressure sensor according to claim 1, wherein the resistance value of the resistor Ra is 240 Ω -320 Ω, and the resistance value of the resistor Rb is 240 Ω -320 Ω.
5. The zero-pressure differential output offset temperature coefficient reduction circuit of a high precision pressure sensor according to claim 1, wherein the resistance value of the resistor Rc is 240 Ω -320 Ω, and the resistance value of the resistor Rd is 240 Ω -320 Ω.
6. The zero-pressure differential output offset temperature coefficient reduction circuit for a high accuracy pressure sensor of claim 1, wherein the temperature coefficient of the differential output offset is ± 0.28mm Hg/° c.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110197452.3A CN112965566A (en) | 2021-02-22 | 2021-02-22 | Temperature coefficient reduction circuit for zero-pressure differential output offset of high-precision pressure sensor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110197452.3A CN112965566A (en) | 2021-02-22 | 2021-02-22 | Temperature coefficient reduction circuit for zero-pressure differential output offset of high-precision pressure sensor |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101275876A (en) * | 2007-03-27 | 2008-10-01 | 捷顶微电子（上海）有限公司 | Design method of bridge arm balance compensating resistance of pressure sensor signal conditioning integrate circuit |
| CN201434687Y (en) * | 2009-06-28 | 2010-03-31 | 海芯科技(厦门)有限公司 | Circuit optimizing common mode electrical level and reducing power consumption of transducers |
| CN104458121A (en) * | 2014-12-15 | 2015-03-25 | 中国燃气涡轮研究院 | Silicon pressure sensor temperature excursion compensating circuit and circuit establishing method |
-
2021
- 2021-02-22 CN CN202110197452.3A patent/CN112965566A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101275876A (en) * | 2007-03-27 | 2008-10-01 | 捷顶微电子（上海）有限公司 | Design method of bridge arm balance compensating resistance of pressure sensor signal conditioning integrate circuit |
| CN201434687Y (en) * | 2009-06-28 | 2010-03-31 | 海芯科技(厦门)有限公司 | Circuit optimizing common mode electrical level and reducing power consumption of transducers |
| CN104458121A (en) * | 2014-12-15 | 2015-03-25 | 中国燃气涡轮研究院 | Silicon pressure sensor temperature excursion compensating circuit and circuit establishing method |
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