CAJ | 학술논문

针对MEMS器件研制中微弱信号的检测问题,提出了一种适用于电容式MEMS器件的微弱电容检测电路.此电路采用峰值检测技术,原理及结构简单;只检测待测电容的变化量,既可用于差分式检测,也可应用于单一待测电容的情况.首先利用正弦载波信号和微分电路对电容量进行载波调制,再通过减法电路得到幅值与电容变化量成比例的正弦信号,最后采用峰值检测方法解调信号,得到直流量输出.利用微小可调电容进行标定,结果表明检测电路的线性度良好,灵敏度约为3.631 V/pF ,精度达到0.2%.利用该检测电路检测MEMS陀螺上振动频率为2.85 kHz的梳齿驱动器的电容量变化,输出信号频率为(2.85±0.02) kHz,误差低于0.7%,说明该电路能够应用于MEMS器件的微弱电容检测.
침대MEMS기건연제중미약신호적검측문제,제출료일충괄용우전용식MEMS기건적미약전용검측전로.차전로채용봉치검측기술,원리급결구간단;지검측대측전용적변화량,기가용우차분식검측,야가응용우단일대측전용적정황.수선이용정현재파신호화미분전로대전용량진행재파조제,재통과감법전로득도폭치여전용변화량성비례적정현신호,최후채용봉치검측방법해조신호,득도직류량수출.이용미소가조전용진행표정,결과표명검측전로적선성도량호,령민도약위3.631 V/pF ,정도체도0.2%.이용해검측전로검측MEMS타라상진동빈솔위2.85 kHz적소치구동기적전용량변화,수출신호빈솔위(2.85±0.02) kHz,오차저우0.7%,설명해전로능구응용우MEMS기건적미약전용검측.
For the measurement of weak signal in MEMS device, a micro capacitance measuring circuit was proposed. The circuit has simple principle and structure, which is based on peak detection method and only measures capacitance variation. Moreover, it can be used not only for differential detection, but also when there is only one sensing capacitor. First, capacitances were modulated by sine carrier wave and differential circuits. Then, sine signal with amplitude proportional to capacitance variation was got by subtraction circuit. Last, modulated signal was demodulated to DC output with peak detection method. Calibration was done with micro adjustable capacitors and a high precision LCR tester. Results indicate that the linearity of the circuit is good, the sensitivity is 3.631 V/pF, and the accuracy reaches 0.2%. Experiment was carried out with the comb actuator with vibration frequency of 2.85 kHz on a MEMS gyroscope. The frequency of output signal is (2.85±0.02) kHZ with relative error no more than 0.7%, which indicates that the micro capacitance measuring circuit is applicable for capacitive MEMS device.