基于单一PMOS差分对的轨到轨输入运算放大器设计  

Design of a rail-to-rail input operational amplifier based on a single PMOS differential pair

作　　者：杨九川 杨发顺 马奎[1,2,3] YANG Jiuchuan;YANG Fashun;MA Kui(College of Big Data and Information Engineering,Guizhou University,Guiyang 550025,China;Semiconductor Power Device Reliability Engineering Research Center of Ministry of Education,Guiyang 550025,China;Guizhou Provincial Key Laboratory of Micro-Nano Electronics and Software Technology,Guiyang 550025,China)

机构地区：[1]贵州大学大数据与信息工程学院,贵州贵阳550025 [2]半导体功率器件可靠性教育部工程研究中心,贵州贵阳550025 [3]贵州省微纳电子与软件技术重点实验室,贵州贵阳550025

出　　处：《电子元件与材料》2023年第6期743-749,共7页Electronic Components And Materials

基　　金：国家自然科学基金(61664004);贵州大学引进人才项目(贵大人基合字[2019]63号)。

摘　　要：基于国内某CMOS工艺设计了一种单一PMOS差分对的轨到轨输入、恒跨导CMOS运算放大器。输入级电路采用折叠共源共栅结构,通过体效应动态调节输入管的阈值电压扩展共模输入范围到正负电源轨,恒定共模输入范围内的跨导,自级联电流镜有源负载将差分输入转换为单端输出;输出级电路采用AB类结构实现轨到轨输出,线性跨导环确定输出管的静态偏置电流。在5 V电源电压,2.5 V共模电压,1 MΩ负载条件下,经Spectre仿真验证,该运算放大器开环增益为119 dB,相位裕度为58°,共模输入范围为0.0027~4.995 V,共模范围内跨导变化小于3%,实现了轨到轨输入共模范围内的跨导恒定。A rail-to-rail input and constant transconductance CMOS operational amplifier was designed with a single PMOS differential pair based on a domestic CMOS process.The input stage circuit adopted folded cascode structure to dynamically adjust the threshold voltage of the input transistors by body effect,which could extend the common-mode input range from positive to negative supply rails.This structure made transconductance stable within common-mode input range.The selfcascaded current mirror,as active-load of input stage,converted differential input signal to an output signal that was referenced to ground.The output stage circuit adopted class AB structure to achieve the rail-to-rail output.Meanwhile,the translinear loop in output stage determines the quiescent bias current of output transistor.The Spectre simulation results show that the open-loop gain is 119 dB,the phase margin is 58°,the common-mode input range is 0.0027-4.995 V and the transconductance variation among common-mode range is less than 3%at the control of 5 V supply voltage,2.5 V commonmode voltage and 1 MΩload.The op-amp achieves constant transconductance within rail-to-rail common-mode input range.

关 键 词：PMOS差分对 轨到轨输入 恒跨导 共源共栅 体效应 

分 类 号：TN722.7[电子电信—电路与系统]