Implementation of a monolithic TPMS using CMOS-MEMS technique

This study demonstrates a novel monolithic TPMS (tire pressure monitoring systems) using CMOS MEMS processes. This TPMS monolithic integrates the 3-axis capacitive accelerometer, capacitive pressure sensor, and platinum (Pt) thermal-resist temperature sensor on a single chip. The TPMS has been successfully implemented using TSMC 2P4M process and our in-house post-process. The footprint of TPMS chip containing sensors and sensing circuits is 2.5 mm times 2.5 mm. Measurement results show that sensitivities of tri-axis accelerometer etch direction are 0.54 mV/G (X-axis), 0.32 mV/G (Y-axis), and 0.19 mV/G (Z-axis). The sensitivities of pressure and temperature sensors are respectively 2.7 mV/ KPa and 1.74 mV/degC.