The Design And Optimization Of Testing System For A MEMS Barometric Pressure Sensor

Meteorological information detection, as an important aspect of national meteorological research, plays an important role in agriculture, industry, meteorology and our life. Meteorological elements mainly include humidity, temperature, barometric pressure and wind speed. A lot of work has been done to realize the detection of these information. With the technical support of MEMS Laboratory on sensors, a piezoresistive barometric pressure sensor has been designed for the detection of high altitude air pressure. Piezoresistive pressure sensor has been widely used in the market with advantages of good stability, simple production process, good linearity and so on.To realize the output signal detection of barometric pressure sensor, in this paper a special interface circuit is designed. The special interface circuit successfully solved the problem of detecting the small change of resistance, and can be used in the detection of pressure within a wide pressure range. Besides, regarding the phenomenon of temperature drift of pressure sensor, an in-depth study has been given and verified. I hope the theory will be helpful to the study in the future.Above all, this paper can be divided into four parts:In part 1, the hardware testing circuit is designed and introduced. The hardware includes stm32 microprocessor, A/D module, LCD module, power module and so on. The main function of the circuit is to realize the acquisition, processing, amplification, transmission and display of the signal. The standard of hardware design is to ensure the stability and integrity of the circuit.In part 2, the software design is completed. The software is mainly responsible for the drive of every module in circuit. Under the combination of hardware and software, the testing work of pressure sensor is completed. Finally, automated batch testing of sensor is realized on the platform of Lab VIEW.In part 3, the performance of the pressure sensor is calculated and analyzed. Through a lot of testing, large amounts of data are obtained. Based on these data, some important parameters of pressure sensor, such as repeatability, linearity, sensitivity are calculated and analyzed. Besides, the digital output of sensor is realized.In part 4, the temperature drift theory is introduced. Through a lot of study, the reason for temperature drift of piezoresistive pressure sensor can be divided into two parts, one is the zero voltage drift, the other one is sensitivity drift. In this paper, a model of offset voltage is given. Moreover, the model is proved to be right. Based on the theory, the temperature compensation is completed.