A Highly Linear, Small-Area Analog Front End With Gain and Offset Compensation for Automotive Capacitive Pressure Sensors in 0.35-<inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m CMOS

Abstract

This paper presents a highly linear, small-area analog front end with gain and offset compensation for automotive capacitive pressure sensor. We propose a capacitance-tovoltage converter circuit that measures the capacitance value of the capacitive sensor with the high accuracy and linearity. In this paper, the linearity of the analog front end is guaranteed using full-analog gain and an offset calibration circuit. The proposed design is implemented using CMOS 0.35 μm technology with an active area of 1.94 mm x 1.94 mm. The full output range is from 0.5 to 4.5 V. The ratiometricity is within ±0.7% when the supply voltage is changed by ±10%. The power consumption is 25 mW from a 5 V supply. The output accuracy is within ±1% with respect to Process, Voltage, Temperature variations.