利用伪随机斩波技术的微弱MEMS信号检测电路  

Weak MEMS Signal Detection Circuit Using Pseudo-random Chopper Technology

作　　者：何鑫[1,2] 王玮冰[1,2] 祖秋艳[1] 宋冬雪 孙业超 

机构地区：[1]中国科学院微电子研究所中国科学院微电子器件与集成技术重点实验室,北京100029 [2]江苏物联网研究发展中心,江苏无锡214135

出　　处：《仪表技术与传感器》2014年第2期87-89,共3页Instrument Technique and Sensor

基　　金：国家科技重大专项(2011ZX02507)

摘　　要：作为一种提高信号增益和降低电路噪声失调的技术手段,斩波放大技术能够比较理想地降低失调和噪声,但是在调制解调过程中,由于开关尖峰和电荷注入效应的影响,调制频率附近的纹波即残余失调和残余的波动幅度仍然造成干扰。为了进一步减小这种失调的影响,提出伪随机斩波技术,利用伪随机信号的相关性可以将周围环境噪声降低,尤其是残余失调的干扰,因此伪随机斩波技术不仅可以将1/f噪声和运放失调降低,还可以有助于减小残余失调。利用上述方法的检测方法经过设计,电路具有120 nV/Hz的输入噪声,闭环增益40 dB,残余失调和1/f噪声降低到理想效果。As a technical method to improve the gain of signal and reduce circuit noise, the chopper stabilization technique can be relatively ideal to reduce offset and noise. However, due to the modulation and demodulation process, switching spikes and charge injection effect has influence over system. As to performance, residual offset still exists and causes interference. In order to further reduce the influence of this offset, using the correlation of the pseudo random signal, the pseudo - random chopper technolo- gy may reduce ambient noise and reduce residual offset. In detecting MEMS sensor signal, these two technologies not only can lower 1/f noise and offset, also could help reduce the residual offset. Using this method, a circuit has been simulated and tested, which has 120nV/Hz input noise and a 40 dB closed loop gain. As aboved simulated,this method has a good effective on noise and off- set.

关 键 词：斩波放大 伪随机频率 残余失调 MEMS 

分 类 号：TN492[电子电信—微电子学与固体电子学]