静电悬浮微加速度计高灵敏度电容检测通道设计

高灵敏度电容式位移检测是实现静电悬浮微加速度计闭环测控的关键技术之一.针对微加速度计径向悬浮检测的特点及指标要求,设计了高灵敏度、高精度电容式微位移检测通道.该通道主要由前置RC隔离网络与C/V转换、高共模抑制比差动放大器、二级运放、二阶压控电压源有源带通滤波、相敏解调(含模拟乘法器与四阶Butterworth低通滤波...

Design of High-sensitivity Capacitive Displacement Sensing Channel for Micromachined Electrostatically Suspended Accelerometer

The capacitive displacement sensing of high-sensitivity is a crucial technique for the closed-loop sensing and control system of micromachined electrostatically suspended accelerometer (MESA). According to the system requirements, characteristics and main specifications of the steady suspension of the MESA, a complete capacitive displacement sensing channel is designed and implemented. This channel, characterized by high sensitivity, high precision and wide stimulation band, is primarily composed of prepositive C/V converter, high-CMRR differential amplifier, Second-order Voltage Controlled Voltage Source (VCVS) active Band Pass Filter (BPF), phase sensitive demodulator(which includes analog Multiplier and fourth-order Butterworth Low Pass Filter), phase shifter for reference carrier output and so on. The static calibration experimental results show that the sensitivity and nonlinearity of the sensing channel are 5.87V/pF and 1.33% respectively, and the displacement resolution is about 7.4nm, and can meet the sensing requirements of the micromachined accelerometer closed-loop suspension control.