Conditioning circuit for precise SiC capacitive pressure sensors

Abstract

Capacitive pressure sensor has many advantages, such as high sensitivity, low temperature drifting and low power consumption. In this paper, capacitive pressure sensor is used as pressure sensor. This paper analyzes SiC MEMS capacitive sensor's features and introduces its conditioning circuit. This sensor has widely commercial exploitation because of its small size and outstanding chemical stability as well as its mechanical character for harsh industrial environment application. Capacitance of this sensor varies at fF or pF degree. As a result, exploitation of such high sensitive capacitive pressure sensor is inhibited by parasitic capacitance in conditioning circuit. Integrated conditioning circuit is introduced for those high-sensitivity capacitive pressure sensors. Measures taken to reduce parasitic capacitance are described in the paper. Experience results give the range and linear area of this sensor.