高转换速率恒定跨导轨对轨运算放大器的设计

A high slew rate operational amplifier with constant transconductance rail-to-rail

基于台积电(TSMC)0.6μmCMOS(互补金属氧化物半导体)工艺设计了一款恒定跨导轨对轨输入/输出运算放大器.不同于传统的实现恒定跨导的技术,在电路设计实现上通过一个简单的检测电路,使互补差分对在整个共模输入电压变化范围内交替工作,实现了跨导恒定.同时为了得到较高的转换速率,加入了转换速率增强结构,使转换速率高达116V/μs.在Hspice仿真平台下,对运算放大器进行了模拟仿真,同时经投片验证,结果表明该轨对轨运算放大器具有良好的性能,静态功耗小于1.5mW.

A constant transconductance rail-to-rail operational amplifier is presented based on TSMC 0.6 μm CMOS （complementary metal oxide semiconductor）process.Being different from traditional constant transconductance methods,a novel circuit developed can make differential input pairs work alternately through a simple detecting circuit,and the transconductance of input stages can keeps constant over the whole common-mode voltage input range.A class AB control circuit is used in the output stage to eliminate crossover distortion and reduce quiescent current.The high slew rate,up to 116 V/μs,in the operational amplifier could be accomplisehed by slew rate enhancement structure.This circuit is simulated by Hspice and fabricated simultaneously.The results indicates the operational amplifier works well and effectively with a consumed less than 1.5 mW.