闭环电容式微加速度计全差分CMOS接口电路  

Full differential CMOS interface circuit for closed-loop capacitive micro-accelerometers

作　　者：刘晓为[1] 尹亮[1] 李海涛[1] 周治平[1] 

机构地区：[1]哈尔滨工业大学微电子技术与科学系,黑龙江哈尔滨150001

出　　处：《光学精密工程》2011年第3期580-586,共7页Optics and Precision Engineering

基　　金：国家863高技术研究发展计划资助项目(No.2008AA04220)

摘　　要：提出了一种用于电容式微加速度计的低噪声、高线性度全差分接口电路。基于开关电容检测技术,该电路采用一种新的双路反馈结构来提高系统线性度,并采用2μmn阱CMOS工艺完成芯片设计。仿真结果证明,电路中采用的双路反馈和全差分检测结构使系统的线性度达到0.01%。加入经过优化设计的比例-微分-积分控制器后,有效减小了系统稳态误差,系统响应速度提高了31%,系统线性度提高了66.7%。在±5 V工作电压下,选取64 kHz作为电路采样频率时,其电路等效输入噪声为8μg·Hz-1/2,系统灵敏度为1.22 V/g,线性度为0.03%,测量范围为±2g。测试结果显示,提出的电路达到高精度微加速度计系统设计要求,可以应用到地震监测、石油勘探等领域中。A CMOS full differential interface circuit with low noise and high linearity was presented for closed-loop capacitive micro-accelerometers. Based on switched-capacitor detection, the circuit was designed to improve its linearity by a 0.5 um n-well CMOS process technology. The simulation result shows that the proposed two-path feedback structure provides a good system linearity of 0.01%. The optimized designed PID controller was added into the system, which decreases the stabilization error effectively, increases the system responding speed by31%, and the linearity by 66. 7%. Witha -4-5 V supply and a sampling frequency of 64 kHz, the circuit can offer the equivalent input noise in 8 ug · Hz-1/2, system sensitivity in 1. 22 V/g, system linearity in 0. 03%, and the work range in ± 2 g. These results prove that this circuit is suitable for applications of high performance micro-accelerometers to seism detection, oil exploration,etc..

关 键 词：闭环电容式微加速度计 全差分接口电路 比例-微分-积分控制器 低噪声 高线性度 

分 类 号：TH824.4[机械工程—仪器科学与技术] TN432[机械工程—精密仪器及机械]