基于充放电原理的小电容测量电路

针对目前的小电容测量电路采样频率低,不能满足瞬态变化的膛压信号测量要求,提出一种基于充放电原理的小电容检测电路。该电路以基于恒流源充放电原理的信号调理电路取代了以小电容检测芯片PS021为主的信号调理电路。测试表明:该小电容检测电路的采样频率达到100kHz,优于国内外现有水平,是一种高采样频率、高精度、低功耗、传感器壳体电容接公共地的小电容测量电路。

Tiny Change Capacitance Measuring Circuit Based on the Principl of Charging and Discharging

The present little capacitance measurement circuit sampling frequency is low,which can not meet the transient changing measurement requirements of bore pressure signal.A small capacitance detection circuit based on charge and discharge principle was proposed in this paper.The signal conditioning circuit with PS021 chips for small capacitance detection was replaced by signal conditioning circuit based on the principle of constant current source charging and discharging.Testing results showed that the sampling frequency of the little capacitance measuring circuit was up to 100 KHz,which was better than the current level inside and outside countries.It was a new capacitance measurement circuit with high sampling rate,low power consumption,and public end grounding.