用于温度传感芯片的开关电容积分器的设计

Design of a Fully Differential CMOS Switched-capacitor Integrator for Temperature Sense IC

设计了一种应用于温度传感芯片的全差分开关电容积分器.在温度传感芯片中,Δ-Σ调制器接收温度传感模块输出电压信号,并将模拟的电压信号转换成对应的数字信号.全差分开关电容积分器是Δ-Σ调制器中最核心的元件,它把接收到的温度传感器模块输出的模拟信号转换为数字信号.在开关电容积分器的实际设计中,存在MOS开关的导通电阻和电荷注入、时钟溃通、采样尖峰等非理想因素.本文对这些非理想因素做了详细的分析,设计了一种全差分的开关电容积分器,可以抵消开关电容中电荷注入和时钟溃通带来的电压误差.同时,本文设计了一种全差分共源共栅放大器,可以很好的满足积分器的要求,从而提高整个系统的性能.

A fully differential CMOS switched-capacitor integrator for temperature sense IC is proposed and analyzed. In the temperature sense IC,△-∑A/D modulator receives the voltage signal from the temperature sensor, and transforms the analog signal to digital signal. Fully differential CMOS switched-capacitor integrator is the main part of the A-Y.A/D modulator. It can realize to trans- form the analog signal received from the temperature sensor to digital. In the practical design process,there are some non-ideal elements with switched-capacitor integrator,such as non-zero Ron,charge injection error, sampling spike and clock feed-through, etc. All of these non-ideal elements were analyzed in this paper and a fully differential was then presented,which can reduce the charge injection error of MOS switches,clock feed-through and non-ideal performance of operational amplifier. The realization of fully differential folded-cascode operational amplifier can improve the performance of the integrator by which the high performance of the whole system can he achieved.