摘要
交流激励式电容测量电路具有对外界干扰敏感与测量精度稳定性差的问题,文中针对该问题开发与设计了一种基于反馈的交流激励式电容测量电路,在电容前端加一反馈,具体为输出电压的倍数加入到初始输入,接着检波采用的是模拟乘法器与低通滤波器,最后得到采集的测量值。对该电路进行实验验证,测量的误差最大为20 nm,分辨率能够在0~650μm内达到30 nm。其结果表明,该电路具有较高的精度与稳定性,满足了电容微测系统的要求。
The AC excitation capacitance measuring circuit has the sensitivity to external interference and the poor stability of measurement accuracy. In this paper, an AC excitation capacitive measurement circuit based on feedback is developed and designed to add a feedback at the front of capacitor, the specific method is to add the output voltage multiples to the initial input, then the analog multiplier and the low pass filter are used to detect the signal, finally, the measured values are obtained. In the end of this paper, the circuit is verified experimentally. The maximum error of measurement is 20nm, and the resolution can reach 30nm within 0 ~ 650 bLm. The results show that the circuit has high accuracy and stability, so as to meet the requirements of capacitive micro measurement system.
出处
《自动化与仪器仪表》
2018年第2期71-73,共3页
Automation & Instrumentation
关键词
交流激励式
电容测量电路
反馈电路
AC excitation type
capacitance measuring circuit
feedback circuit
