一种双极型轨到轨功率运算放大器  

A Bipolar Rail-to-Rail Power Operational Amplifier

作　　者：韩前磊 臧凯旋 孔祥艺 李珂[1] Han Qianlei;Zang Kaixuan;Kong Xiangyi;Li Ke(The 58th Research Institute,CETC,Wuxi 214000,China)

机构地区：[1]中国电子科技集团公司第五十八研究所,江苏无锡214000

出　　处：《半导体技术》2020年第12期924-930,共7页Semiconductor Technology

摘　　要：基于双极型工艺设计了一种双通道轨到轨功率运算放大器,其功能模块包括:基准偏置、输入级、中间级和输出级电路。输入级电路采用两组npn、pnp型差分输入对管组成的轨到轨输入结构,配合电流开关电路实现输入级的跨导恒定;中间级电路选择电压跟随器结合电流跟随结构,实现将双端输入转为单端输出;输出级电路为具有3阶放大能力的AB类结构,实现轨到轨输出的同时提高电流放大能力;芯片内还集成了电流检测、反向电流保护、静电放电(ESD)保护等相关电路。该运算放大器采用双极型工艺流片。实测结果表明:该功率运算放大器的输入失调电压小于1 mV,输入失调电流小于2 nA,开环电压增益大于120 dB,增益带宽积大于4.5 MHz,短路电流大于100 mA,压摆率大于1.5 V/μs。A dual-channel rail-to-rail power operational amplifier was designed based on bipolar process.Its functional modules included the reference bias circuit,input stage,intermediate stage and output stage circuit.The input stage circuit adopted a rail-to-rail input structure composed of two sets of npn-and pnp-type differential transistor pairs,and cooperated with the current switching circuit to realize the constant transconductance of the input stage.The intermediate stage circuit choiced the voltage follower combined with the current following structure to realize the conversion from double-end input to single-ended output.The output stage circuit was a class AB structure with third-order amplification capability,which achieved rail-to-rail output while improving the current amplification capability.And the current detection,reverse current protection,electrostatic discharge(ESD)protection and other related circuits were integrated in the chip.The power operational amplifier was fabricated in a bipolar process.The test results show that the input offset voltage is lower than 2 nA,the input offset current is smaller than 1 mA,the open loop voltage gain is greater than 120 dB,gain bandwidth product is higher than 4.5 MHz,the short circuit current is larger than 100 mA,and the slew rate is greater than 1.5 V/μs.

关 键 词：运算放大器 双通道 轨到轨 跨导恒定 双极型 

分 类 号：TN431[电子电信—微电子学与固体电子学]