峰值电流模DC-DC转换器中多功能误差放大器电路设计

摘要

提出了一种适合于峰值电流模DC-DC转换器的新型多功能误差放大器电路.与斜坡电压信号结合可实现软启动功能,实现了从启动阶段到稳定工作状态的平滑过渡,无扰动出现,并有效地消除了启动阶段的浪涌电流和电压过冲;同时还具有最大电流限制和模式切换功能.该误差放大器集成到一款峰值电流模升压型DC-DC转换器中,电路采用CSMC 0.5μm BCD工艺实现.仿真结果表明:3.5V的输入电压下,误差放大器消耗的静态电流为4.48 μA,并且能够实现软启动、最大电流限制、模式切换功能.电路具有简单易实现,功耗低的特点.%A novel error amplifier with integration of multi-functions for peak-current mode DC-DC converters is presented.Soft-start is achieved by the error amplifier combined with a ramp voltage signal.A smooth transition from startmode to the steady state is achieved without disturbance,and the inrush current and the overshoot of the output voltage during start-up are eliminated effectively.Moreover,this novel error amplifier has other two functions,which are the maximum current limit and working mode switching.The error amplifier is applied to a peak-current mode BOOST DC-DC converter that is implemented with CSMC 0.5 μm BCD process.Simulation results show that the static current consumption of the error amplifier is 4.48μA with 3.5V supply voltage,and the soft-start,maximum current limit and working mode switching functions are achieved by the multi-functions error amplifier.The presented circuit is concise and simple to implement,and has features of low power.