CN2476012Y - Silicon pressure sensor - Google Patents

Abstract

A silicon pressure sensor comprises a silicon pressure sensitive element and a differential amplifier, the output end of the differential amplifier is provided with an output coupling resistance. A thermal resistance whose temperature coefficient is just opposite to that of the silicon pressure sensitive element is arranged on the outer surface of the silicon pressure sensitive element, the thermal resistance and the output coupling resistance are connected in parallel. The utility model can counteract the influence of temperature of the silicon pressure element to achieve the purpose of temperature compensation, thus to improve the measuring accuracy of the sensor. The utility model can meet the requirement of high accuracy, low cost and single use of the atmospheric pressure, and can make the silicon pressure sensor be applied in atmospheric sounding.

Description

Silicon pressure sensor

The utility model is a kind of silicon pressure sensor, especially for the silicon pressure sensor on the aerological comprehensive survey instrument.

Silicon pressure sensor has its very big advantage compared with traditional aneroid capsule baroceptor: good stability, highly sensitive, lag behind little, but its shortcoming also is fatal: silicon is very big as its temperature coefficient of semiconductor material, will almost can not use because of precision is too low so that do not do temperature compensation.General temperature compensation is that the pressure that the change in resistance compensation temperature that its temperature causes causes changes at the inner thermistor that adds of silicon pressure-active element, and the electric weight that makes output is simple pressure variety.This method is because complex process and cost is very high, and aerological comprehensive survey instrument is again unrenewable after the disposable use, and therefore, existing silicon pressure sensor is not suitable on the aerological comprehensive survey instrument.

The purpose of this utility model is exactly for a kind of silicon pressure sensor of high-precision low cost being provided, can reaching tonometric accuracy requirement in the fields such as aerological sounding, can make its cost lower and be suitable on the aerological comprehensive survey instrument again.

The technical solution of the utility model is: a kind of silicon pressure sensor, comprise silicon pressure-active element and differential amplifier, and it is characterized in that: amplifier out is set up an output repeating resistance; On the outside surface of silicon pressure-active element or near a thermistor is set, the temperature coefficient of thermistor is just in time positive and negative opposite with the temperature coefficient of silicon pressure-active element, thermistor with output repeating resistance in parallel.

Be further described below in conjunction with embodiment of the present utility model and accompanying drawing thereof.

Fig. 1 is the electrical schematic diagram of the utility model embodiment.

Referring to silicon pressure sensor shown in Figure 1, include silicon pressure-active element P, thermistor Rt, amplifier U1, U2, resistance R 1, R2, R3, R4, R5, R6, R7.Silicon pressure-active element P has four ends, and end 1 connects power supply, holds 3 ground connection, and end 2 and end 4 respectively insert the positive input terminal of amplifier U1, U2 by R5 and R6; The output terminal connecting resistance R3 of amplifier U1, the negative input end of resistance R 3 another termination amplifier U2, the end of the output termination repeating resistance R7 of amplifier U2; Between the negative input end and output terminal of resistance R 2 and resistance R 4 difference bridging amplifier U1, U2; The one termination amplifier U1 negative input end of resistance R 1 and the contact of resistance R 2, other end ground connection; Thermistor Rt is placed on silicon pressure-active element P surface, also can be placed near it, and its two ends are in parallel with repeating resistance R7, and by resistance R 7 outputs.Amplifier U1, U2 and on every side resistance R 1, R2, R3, R4, R5, R6 form differential amplifier, wherein set R1=R4, R2=R3, the gain $A=\frac{R4}{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="Y0123929000051.png"\; state="\{\{state\}\}">R</figure-callout>}3}+1.$ Silicon pressure-active element P has negative temperature coefficient, and thermistor Rt then adopts positive temperature coefficient (PTC), for the absolute value that makes two temperatures coefficient equates, at thermistor Rt two ends and meet repeating resistance R7, to change the variable quantity of thermistor Rt.The pressure variety of silicon pressure-active element P is exported by the R7 coupling after amplifying circuit amplifies; Simultaneously, the change in resistance of thermistor Rt changes the resistance at R7 two ends, when the pressure variety temperature influence of silicon pressure-active element P becomes big, because thermistor Rt is opposite with the temperature coefficient of silicon pressure-active element P, thermistor Rt resistance reduces, the resistance at R7 two ends reduces thereupon, and the pressure variety of output also will reduce, and vice versa.When calibration, regulate the R7 resistance, the variable quantity that makes thermistor Rt is identical with the variable quantity of silicon pressure-active element P temperature influence and direction is opposite, like this, the temperature variation of thermistor Rt output is with the variable quantity of offset silicon pressure-active element P temperature influence, and the electric weight of exporting through R7 is temperature compensated pressure variety.

Good effect of the present utility model is and can be subjected to the temperature shadow in the pressure-sensitive element of the offset silicon institute measured value The value of ringing reaches the purpose of temperature-compensating, greatly improves the certainty of measurement of sensor; Especially, In the pressure-sensitive element of silicon outside compensating element, being set---thermistor, technology is simple, has high-precision Degree, cheaply characteristics; The measurement that can satisfy atmospheric gas pressure is high accuracy, low cost, once The requirement of property use is applied silicon pressure sensor in Atmospheric Survey; If needed also Can be used for the measurement of liquid pressure.

Claims (1)

1. A kind of silicon pressure sensor comprises silicon pressure-active element and differential amplifier, it is characterized in that: amplifier out is set up an output repeating resistance; On the outside surface of silicon pressure-active element or near a thermistor is set, the temperature coefficient of thermistor is just in time positive and negative opposite with the temperature coefficient of silicon pressure-active element, thermistor with output repeating resistance in parallel.

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