一种新的不受寄生电容影响的电容式传感器接口电路

给出了一种新的用于微小电容检测的接口电路 .在电荷传送电路的基础上,引入了一个用于参考微变电容读出的电荷传送电路部分,将检测电路与参考电路的输出进行差分放大,从而大大提高了电路的稳定性和检测灵敏度,同时此电路也保持了电荷传送电路检测微小电容变化不受寄生电容影响的特性.

A New Stray-Immune Interface Circuit for Capacitive Sensors

A novel interface circuit is presented to detect the minimal change of the differential capacitance.Based on the charge transfer circuit,the interface circuit introduces another charge transfer circuit detecting the reference differential capacitance.By differentially amplifying the output of the detecting and reference circuit,the interface circuit shows better stability and much higher sensitivity.At the same time,it keeps the characteristic of high immunity to parasitic capacitance.