一种引进相位裕度的∑Δ调制器行为级模型  

Behavioral Model of Sigma Delta Modulator by Introducing Phase Margin

作　　者：刘爱荣[1] 杨斌[1] 杨华中[1] 

机构地区：[1]清华大学电子工程系清华信息国家实验室,北京100084

出　　处：《固体电子学研究与进展》2009年第1期89-92,105,共5页Research & Progress of SSE

基　　金：国家项目863(2006AA01Z224)资助

摘　　要：相位裕度是影响运算放大器建立方式和建立精度的一个重要参数,在高速度高精度应用中,获得高的单位增益带宽的同时获得大的相位裕度变得非常困难。通过引入相位裕度参数提出了一种更加完整的开关电容积分器二阶瞬态响应模型,并将此模型引入到传统的ΣΔ调制器行为级模型,通过仿真分析了相位裕度对积分器建立精度以及ΣΔ调制器信噪比的影响。仿真结果表明,在其他参数相同的情况下,当相位裕度变化10°时,ΣΔ调制器的信噪比变化近5dB。Phase margin has an important effect on the settling way and the settling accuracy of the OTA（Operationd transconductance amplifier）. In high speed high resolution applications, it is difficult to get high unity gain bandwidth and large phase margin at the same time. In this paper, by introducing phase margin a second order transient model of the switched capacitor integrator is proposed and this model is introduced to the conventional behavioral modeling of SDM （sigma delta modulator）. The effect of phase margin on the accuracy of the integrator and the performance of the modulator is analyzed by simulation. Simulation results show that in high speed high resolution applications when the phase margin of the OTA varies 10° the SNR （Signal to noise ratio） of the sigma delta modulator will vary 5 dB.

关 键 词：∑△调制器 行为级模型 相位裕度 

分 类 号：TN761[电子电信—电路与系统]