一种恒跨导高增益轨到轨运算放大器  

A Constant-g_m High Gain Rail-to-Rail Operational Amplifier

作　　者：唐俊龙[1] 黄思齐[1] 罗磊[1] 涂士琦 肖仕勋 龚磊[1] 刘远治 谢海情[1] TANG Junlong;HUANG Siqi;LUO Lei;TU Shiqi;XIAO Shixun;GONG Lei;LIU Yuanzhi;XIE Haiqing(School of Physics ＆ Electronic Science,Changsha University of Science ＆ Technology,Changsha 410114,P.R.China)

机构地区：[1]长沙理工大学物理与电子科学学院,长沙410114

出　　处：《微电子学》2018年第4期458-462,共5页Microelectronics

基　　金：国家科技支撑计划资助项目(2014BAH28F04);国家自然科学基金资助项目(61404011);湖南省自然科学基金资助项目(2015JJ3001);湖南省教育厅科研资助项目(17K004)

摘　　要：基于TSMC 0.18μm CMOS工艺,设计了一种新颖的恒跨导高增益轨到轨运算放大器。输入级仅由NMOS管差分对构成,采用电平移位及两路复用选择器控制技术,在轨到轨共模输入范围内实现了输入级恒跨导。中间级采用折叠式共源共栅放大器结构,运算放大器能获得高增益。输出级采用前馈型AB类推挽放大器,实现轨到轨全摆幅输出。利用密勒补偿技术进行频率补偿,运算放大器工作稳定。仿真结果表明,在1.8V电源电压下,该运算放大器的直流开环增益为129.3dB,单位增益带宽为7.22MHz,相位裕度为60.1°,整个轨到轨共模输入范围内跨导的变化率为1.44%。A novel high gain rail-to-rail operational amplifier circuit was designed in TSMC 0.18μm CMOS process.The input stage of the circuit was composed of only NMOS differential pairs.The level shift circuit and the two channel multiplexers were used to keep the input stage constant-gmin the rail-to-rail common mode range.A folded cascode amplifier architecture was used in the intermediate stage of the amplifier to ensure that the operational amplifier could achieve high gain.The rail-to-rail output was achieved by the feedforward class AB pushpull amplifier in the output stage.The Miller compensation was used to ensure that the operational amplifier could operate in a stable state.Simulation results showed that the DC open loop gain of the operational amplifier was 129.3 dB when the amplifier operated at 1.8 V power supply voltage,the unit gain bandwidth was 7.22 MHz,the phase margin was 60.1°,and the overall transconductance variation was only 1.44% over the rail-to-rail common mode input range.

关 键 词：恒跨导 高增益 轨到轨 运算放大器 

分 类 号：TN432[电子电信—微电子学与固体电子学] TN722.77