Sigma-Delta微加速度计非理想因素建模与系统级设计  

Model Building of Nonideal Factors in Sigma-Delta Accelerometer and System Level Design

作　　者：刘云涛[1,2] 王颖[1] 

机构地区：[1]哈尔滨工程大学信息与通信工程学院,哈尔滨150001 [2]中国科学院微电子研究所,北京100029

出　　处：《传感技术学报》2011年第11期1532-1537,共6页Chinese Journal of Sensors and Actuators

基　　金：中央高校基本科研业务费专项资金项目(HEUCF110801)

摘　　要：为了简化Sigma-Delta(ΣΔ)微加速度计接口电路晶体管级的仿真和优化,建立了系统中的非理想因素模型,并在此基础上完成了一种单环结构的ΣΔ微加速度计的系统级设计。分析了敏感结构中固定极板运动、时钟抖动、开关热噪声、运算放大器噪声等非理想因素对系统的影响,并分别建立了Simulink模型。基于所建模型,设计了一种ΣΔ微加速度计的精确的Simulink模型。系统级仿真结果表明:二阶系统的信号-噪声-谐波失真比(SNDR)为70.1dB,有效位(ENOB)为11.36位,四阶系统的SNDR为92.7dB,ENOB为15.7位。对比于晶体管级仿真结果,基于本文所建立的非理想因素模型的系统仿真可以准确地表述出系统性能,同时大大缩短了仿真时间,简化了传感器设计中的参数优化过程。Precise models of nonideal factors in capacitive Sigma-Delta（ΣΔ）micromachined accelerometer and a Simulink model of single-loop Sigma-delta accelerometer are presented to facilitate the transistor-level simulations and optimization.The influences of main nonideal factors including the motion of fixed electrode,clock jitter,thermal noise of switches and noise of operational amplifier to the system are analyzed.For each nonideal factor,a description of the considered effect as well as the implementation details with Simulink is provided.Based on these models,a precise Simulink model of ΣΔ accelerometer is proposed.The system level simulation results indicate that signal-to-noise-and-distortion ratio（SNDR）of second-order system is 70.1dB,effective number of bits（ENOB）is 11.36bits,and SNDR of fourth-order system is 92.7dB,ENOB is 15.7bits.Compared with transistor-level simulations,the system model could describe the performance of system accurately,meanwhile saving the simulation time and simplifying the process of optimization greatly.

关 键 词：微加速度计 SIGMA-DELTA 系统级建模 非理想因素 

分 类 号：TP824[自动化与计算机技术—检测技术与自动化装置]