Switched Capacitor Signal Conditioning for Push-Pull Type Capacitive Sensors

Abstract

A novel switched capacitor signal conditioning circuit is developed for differential capacitive sensors. The main advantage of the preferred method lies in the fact that it accepts sensors possessing either linear or inverse characteristics and provides a linear output. Moreover, the output is dependent only on a pair of DC reference voltages and the transformation constant of the sensor. Hence increased linearity and accuracy is easily achieved by employing precision DC reference voltages. Results from the tests on a prototype elucidate the practicality of the proposed method