高性能微加速度计接口电路的研究

High Performance Interface Circuit for Micromachined Accelerometer Sensors

介绍一种可用于微机械电容式加速度计检测的接口电路,该电路利用电荷放大器把电容变化转变成电压变化,再对被加速度信号调制的载波信号进行解调,经过低通放大滤波,最后得到与加速度信号成正比的直流电压信号,具有测量差分电容变化的功能和灵敏度高、线性好的特点。整体电路通过Pspice进行了仿真,优化后制成PCB板进行实验。实验结果线性度为5%,灵敏度为19.5 V/pF,表明该电路是一种具有实用价值的电容式加速度计检测接口电路。

Introduced a interface circuit for capacitive micromachined accelerometer sensors. First it changed the variety of capacitive into the variety of voltage by charge amplifier, then demodulates the cartier wave signal modulated by the accelerometer signal and passed thought the low pass filter, at last, output a direct current signal which is directly proportional the accelerometer signal, the circuit has the function of measuring the variety of capacitive and the specialties of higher sensitive and better linearity. The whole circuit is simulated and optimized by the Pspice, then processed into PCB. The results of measurement were the linearity of 5 % and the sensitivity of 19.5 mV/tF, it＇s proved that the interface circuit has utility value for the measurement of capacitive micromachined accelerometer sensors.