基于偏流补偿的低失调运算放大器的设计  

Design of a low offset operational amplifier based on bias current compensation

作　　者：李洪品 杨发顺 马奎[1,3] LI Hongpin;YANG Fashun;MA Kui(College of Big Data and Information Engineering,Guizhou University,Guiyang 550025,China;Engineering Research Center of Semiconductor Power Device Reliability,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：《微电子学与计算机》2024年第5期140-146,共7页Microelectronics & Computer

基　　金：贵州大学引进人才项目(贵大人基合字(2019)63号);黔科合支撑[2023]一般283资助项目(202359075590422170)。

摘　　要：基于双极型工艺,设计了一种具有低输入失调电压、低输入偏置电流的运算放大器。电路结构包含偏置电路、差分输入级电路、中间级电路和输出级电路。差分输入级电路采用共射-共基耦合对,能够降低失调电压,并且采用基极电流补偿结构抵消输入偏置电流在外围电路上所产生的影响,提高电路精度。中间级为整个电路提供增益,并且将双端输入信号转换为单端输出信号。输出级电路为AB类输出级,具有低静态功耗,能够提高电路效率,增大电路带负载能力并为负载提供更多功率。电路采用齐纳修调技术,在封装后对芯片进行修调,避免封装后引入的二次失调。流片后测试结果表明:在±15 V电源电压条件下,输入失调电压≤10μV,输入偏置电流≤3 nA,输入失调电流≤1.5 nA,大信号电压增益≥110 dB。An operational amplifier is designed based on bipolar process with low input offset voltage and low input bias current,which includes bias circuit,differential input circuit,intermediate circuit and output circuit.The differential input stage adopting cascode differential pairs can decrease offset voltage.Meanwhile,the base current compensation structure included in differential input stage can neutralize the influence of input bias current on peripheral circuitry and can increase circuit's accuracy.The intermediate stage provides gain for the overall circuit and converts differential input signal to an output signal that is referenced to ground.The output stage,as Class AB structure that consumes low static power,improves circuit's efficiency,boosts loading capability and provides more power for load.The circuit adopting Zena trimming can trim the chip after packaging,which can avoid second offset introduced after packaging.After taping out,the test results show that input offset voltage of less than 10μV,input bias current of less than 3 nA,input offset current of less than 1.5 nA,large signal voltage gain of more than 110 dB at±15 V power supplies.

关 键 词：运算放大器 低输入失调电压 低输入偏置电流 基极电流补偿 齐纳修调 

分 类 号：TN722.77[电子电信—电路与系统] TN431.1