Pressure sensor temperature drift compensation circuit and compensation method

Abstract

The invention discloses a pressure sensor temperature drift compensation circuit, which comprises a subtracter, wherein the subtracter comprises an operational amplifier, a diode, a first resistor, asecond resistor and a third resistor, an output end of the operational amplifier is connected with an input end of a voltage-sensitive Wheatstone bridge, an inverted input end of the operational amplifier is connected with an input power supply of the subtracter through the first resistor, the inverted input end and the output end of the operational amplifier are connected through the second resistor, an in-phase input end of the operational amplifier is connected with the ground through the third resistor and is connected with the input power supply through the diode, a positive electrode ofthe diode is connected with the input power supply, and a negative electrode of the diode is connected with the in-phase input end of the operational amplifier. The invention further discloses a compensation method correspondingly. The compensation method is that the ratio of the second resistor and the first resistor is adjusted so as to enable zero point temperature drift [beta] of a pressure sensor to be equal to abs([alpha]), wherein the [alpha] is a temperature coefficient of output voltage VO of the subtracter. The circuit and method disclosed by the invention has the advantages of improving the compensation accuracy and the like.

Description

technical field [0001] The invention mainly relates to the technical field of pressure measurement, in particular to a pressure sensor temperature drift compensation circuit and compensation method. Background technique [0002] At present, pressure sensors are widely used in aerospace, industry, automotive electronics, artificial intelligence, medicine, meteorology and other fields, and various application fields also put forward higher and higher requirements for their performance indicators. [0003] The most widely used pressure sensors now mainly include diffused silicon piezoresistive pressure sensors and sputtered thin film pressure sensors. The pressure sensors of both principles contain a Wheatstone pressure-sensitive bridge inside, whether it is a diffused silicon resistor or a metal film resistor. All have positive temperature coefficient characteristics. As the temperature rises, its resistance will increase. In the case of constant voltage power supply, as the t...

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Problems solved by technology

However, due to the difference in process methods, the temperature characteristics of each pressure-sensitive Wheatstone bridge will be different, and the patent CN105784215A mainly realizes the temperature compensation of different types of sensors by changing the number of series diodes, and the voltage drop of the diode 2CK4148 used in it varies with temperature Change rate ΔV t ≈-2.5mV / ℃, and approximately linear, in the case of 10V constant voltage power supply, the temperature coefficient of the pressure sensor that can be compensated is T C ≈n*0.025%FS / ℃ (n is the number of diodes), there are two main disadvantages in this method, the first disadvantage is that the calculation method of the number of diodes is relatively complicated, and the calculation results are not necessarily accurate; the second disadvantage is that it cannot Accurately compensate the temperature coefficient of sensor sensitivity, because the number of diodes can only be an integer, so it is either under-compensated or over-compensated. The product can theoretically achieve the sensitivity temperature drift after compensation β=±0.0125% FS / ℃, which obviously cannot meet the current requirements. Wide temperature range and high precision requirements in many applications

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