A High Accuracy Signal Conditioning Method and Sensor Calibration System for Wireless Sensor in Automotive Tire Pressure Monitoring System

Tire Pressure Monitoring System (TPMS) is used to detect when one or more of the vehicle's tires is 25 percent or more below the manufacturer's recommended inflation pressure. A TPMS system consists of four wireless sensors, a high frequency (HF) antenna and a central receiver. In this paper, a high accuracy sensor incorporated with a sensor signal conditioning chip is presented. A new TPMS wireless signal conditioning method for automotive applications is developed. The signal conditioning method consists of a signal conditioning chip and a calibration algorithm. The calibration algorithm has been established by relating to measured voltage, temperature and pressure ADC reading at three different temperature ranges. Twenty-five relating coefficients are obtained from characterization test before sensor signal conditioning is applied to TPMS wireless sensor calibration. The test results show that the signal conditioning method provides higher accuracy performance for wireless sensor within a battery supply voltage range from 2.1 V to 3.6 V and a temperature range from -40degC to 125degC. The signal conditioning method also reduces the cost of wireless sensor. Moreover, a presented sensor calibration system helps to improve production efficiency and lower production costs.