All switched-capacitor realized piezoresistive pressure sensor interface chip for automotive TPMS

Abstract

An all switched-capacitor structure realized piezoresistive pressure sensor interface chip for automotive tire pressure monitoring system is presented. The propose integrated circuit consists of high resolution incremental ADC, low noise switched-capacitor amplifier, high accuracy bangdap reference and low-power relaxation oscillator and other related blocks. Proposed structure was implemented in standard 0.35 µm CMOS process with an area of 6.1 mm 2 . The experimental results show that the signal conditioning method provides high accuracy of 1% of the full scale output with a battery voltage from 3.6 V to 2.1 V over the full military temperature range. The charge consumption results into 25 mAh in 10 years, including sleep mode and junction leakage current.

Signal processing system-on-chip design for biomedical applications

“…All switches are controlled by digital systems. The PGA provides full calibration for the sensor's inherent temperature drift and nonlinearity, and supports multiple temperature sensing methods [9,10]. The transfer function is shown in Eq.…”

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