适用于纹波控制型DC-DC变换器的比较器设计

Design of PWM Comparator for DC-DC Converter Based on Ripple Control

设计一种适用于纹波控制(Output-Ripple-Based Control)的Buck型DC-DC变换器的比较器,根据PSIM搭建的仿真模型,分析主环比较器性能对系统的影响,设计具有三级预放大的高增益,低延时,低失调电压的比较器电路,采用两种温度系数的电流补偿比较器增益,稳定增益,采用0.5μm BiCOMS工艺进行仿真验证,下降沿延时27 ns,增益123 dB,随温度最大增益变化3.2%,失调电压90μV,达到系统要求。

A kind of comparator applicable to Output-Ripple-Based Control DC-DC Converter was put forward. By using PSIM to build simulation model,and analysing the main loop comparator＆#39;s performance,the influence of the system,a comparator circuit with preamplifier of high gain,low delay,low disorder voltage were designed. The two kinds of temperature coefficient of bias current are using to compensate the comparator＆#39;s gain,By using 0. 5 μm BiCOMS process to simulation verification,the falling edge delay is 27 ns,gain is 123 dB,the biggest gain 3. 2%with temperature changes,offset voltage 90 μV and they all reach the system requirements.