采用输入信号适配技术的BiCMOS运放

为了满足高性能开关电源中集成运放的应用需要,设计了一种结构简单且具有轨对轨输出的运算放大器.该运放基于0.5μm BiCMOS 工艺,采用浮动输出的输入信号适配器(ISAFO),将输入信号放大至差分输入级的工作区域,从而实现了轨对轨的运行.对所设计的运放进行了仿真分析,结果表明在工作电源电压为±0.75 V、外接100 kΩ电阻的条件下,该运放的直流开环增益达到了102 dB,单位增益-带宽为6.35 MHz,相位裕度为62.5°,而功耗仅约为150 μW.所设计的运放具有很宽的共模输入范围及较高的增益,所以特别适用于开关电源的误差放大器、过流、过压和过热保护模块中.

BiCMOS Operational Amplifier Using Input Adapter Technology

To meet the needs of integrated operational amplifier applied to high-performance switching power supply, a simple rail to rail operational amplifier was presented. The operational amplifier based on 0.5 μm BiCMOS technology uses input signal adapters with floating output (ISAFO), translates the input signals into the operating region of the differential amplifier,and achieves rail-to-rail operation.The simulation results show that the DC open-loop gain of the operational amplifier is 102 dB, and the unity gain frequency is 6.35 MHz, and the phase margin is 62.5°with the power voltage is 0.75 V and the resistance is 100 kΩ. The power consumption is only 150 μW.Because of the wide input common-mode range, it is especially suitable for error amplifier, over-current, over-voltage and over-temperature protection module of the switch power supplies.