A Wafer-level pressure calibration method for integrated accelerometer and pressure sensor in TPMS application

Abstract

The tire pressure monitoring system (TPMS) normally contains an accelerometer. For piezoresistive accelerometers, low cost wafer-level full-range calibration is still a challenge. A novel wafer-lever pressure calibration method for accelerometer is reported in this paper. This method can be applied on a beam-block-membrane structure accelerometer which is sensitive to both acceleration and pressure. By measuring accelerometer's full-range response in a static pressure test step, the method can significantly reduce testing cost and workload in TPMS sensor production. Integrated pressure sensor can also be tested in this pressure test step. Simulation results show the feasibility to calculate the accelerometer's response from pressure test results. An integrated sensor (100g+500kPa measure range) for TPMS application was fabricated and measured through pressure test.