微小电容式传感器测量系统设计  

Design of Measurement Circuit System for Micro-capacitance Sensor

作　　者：曹志广 李冬梅[1] 代雁冰 李铁[2] 孙富钦 张珽[2] CAO Zhiguang;LI Dongmei;DAI Yanbing;LI Tie;SUN Fuqin;ZHANG Ting

机构地区：[1]上海大学材料科学与工程学院,上海200436 [2]中国科学院苏州纳米技术与纳米仿生研究所国际实验室,江苏苏州215123

出　　处：《计量与测试技术》2020年第6期1-4,8,共5页Metrology & Measurement Technique

基　　金：国家重点研发计划变革性技术课题(2017YFA0701101);国家自然科学基金(51702354、61574163);江苏省杰出青年科学基金(BK20170008)资助。

摘　　要：本文研究了一种基于微分运算原理测量微小电容式传感器的电路系统,通过理论分析和实验验证了微小电容式传感器容值与系统测量所得电压有效值间的关系。系统采用文氏电桥电路作为稳定信号源,并在微分运算电路中接入待测传感器,输出信号随待测传感器应变。微分电路的输出经信号由主控芯片对其进行模数转换和运算处理,传感器测量结果可在串口打印显示,也可无线发送给外部设备,使小电容测量智能化。系统的传感器容值与输出电压有效值间转换为完全线性相关,结果易于处理,且不易受分布电容影响。此外,系统无需外接信号源,且可通过调节微分电路电阻值实现多容值范围的传感器测量。电路结构简单,易于实现,系统稳定,抗干扰性强。The present study investigates a circuit system for measuring micro-capacitive sensors based on the principle of differential operation,by which the correlation between the effective value of the output voltage and the capacitive sensor to be measured is theoretically explored,and the relationship between the sensor’s capacitance and the output voltage is verified.The wien bridge oscillator circuit acts as a stable signal source,and the capacitive sensor to be measured is connected to the differential operation circuit,thus the output signal is strained by the capacitive sensor to be measured.The output signal of the differential circuit is converted by the main control chip from analog signal to digital signal,and the sensor measurement result can be printed on the serial port or sent to the external receiving device via wireless module,making the measurement of small capacitive sensor smarter.The present system demonstrates that it is a complete linear correlation between the sensor capacitance and output voltage,and the result is easy to process and not susceptible to distributed capacitance.In addition,this system can realize multi-range sensors’measurement by adjusting the resistance value of the differential circuit,whose structure is concise and has good anti-interference performance.

关 键 词：微分运算 微电容传感器 智能测量 无线传输 电路 

分 类 号：TN911[电子电信—通信与信息系统]