A study of the current and charge sensing circuits for micropositioners

• Main Author: 黃少侃
• Other Authors: Tsunglin Chen
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/41402842939586243550

碩士 === 國立交通大學 === 機械工程系所 === 96 === Micropositioner, which provides the advantages such as high precision, the driving capability on wide-frequency bandwidth and the lower costs, belongs to Micro-electromechanical Systems (MEMS). Therefore it is widely used in the magnetic or optical storage device. The values of the two capacitors change because the distance between the moving element from upper and lower electrodes are changing respectively while the moving element is vibrating in a fixed frequency. There is a net charge proportional to the mismatch between the two sensing capacitor. Differentiating the charge yields current. Input charge and current into the corresponding op-amp respectively, and by the processing of op-amp, there is an output signal which is function of velocity or displacement of the micropositioner. Measuring the output signal then we can get the velocity or displacement of the micropositioner. Furthermore by the signal to noise ratio, we can get the magnitude of minimum detecting displacement, or call it resolution.