A Tire Pressure Monitoring System Based on MEMS Sensor

TPMS (Tire Pressure Monitoring System) has played a more and more significant role in safely driving nowadays. Low power consumption and excellent accuracy are two of the most important parameters. In this paper, a TPMS with driving status judgment and low-power measurement is designed and realized. A vibration switch is applied to judge the different status of running and stopping. Based on the judgment of driving status, pressure and temperature, different operations will be carried out in order to achieve lower power consumption. The whole system is working intermittently. It has a good performance with a theoretical lifespan of 2 years. The tested communication distance is more than 30m and the resolution is better than 4KPa. A MEMS pressure sensor using SOI wafer with high consistency and accuracy for this TPMS is designed and fabricated. Deep trench etching is adopted to make pressure reference cavity. The ratio of sensitivity variance to its average is 3.5%, which illustrates a good consistency. The total accuracy of the sensor is better than 0.3% and the nonlinearity is less than 0.2%.