Signal conditioner for MEMS based piezoresistive sensor

Silicon piezoresistors are widely used for making microsensors like pressure sensors, accelerometers etc. A major problem associated with piezoresistive sensors is their dependence of resistance with respect to temperature. This paper proposes a novel low-cost technique to compensate for the temperature dependence of piezoresistive sensor configured in a Wheatstone bridge. A calibration algorithm is established by relating temperature and pressure sensor readings at three different temperature ranges. The test result shows that the signal conditioning method provides thermal error less than 0.25% in the compensated temperature ranges -10 °C to +70°C. The obtained results show the offset compensation is up to 50 mV and sensitivity is of 250 mV/bar. These results are discussed and found comparable with reported data. Sensor repeatability and process repeatability were tested. The digital process of temperature compensation using software and hardware is discussed.