一种适用于基于纹波的恒定导通时间架构Buck变换器片内纹波补偿方案

摘要

Subharmonic oscillation will exist when ceramic capacitors are used as the output filter capacitors of ripple-based constant on-time (RBCOT) Buck converter. A novel on-chip ripple compensation scheme is proposed in the paper to alleviate such problem. This ripple compensation scheme can enhance system stability without adding any IC peripheral components and has good transient response performance. Describing function (DF) method is used to derive the small-signal model and analyze the stability of the proposed ripple compensation scheme. Simplis simulation results verify the system model and stability criterion derived. The experimental results further validate the theoretical analysis.%提出一种新颖的可以集成在芯片内部的纹波补偿方案,解决了当陶瓷电容作为基于纹波的恒定导通时间(RBCOT)架构 Buck 变换器输出滤波电容时出现的次谐波振荡问题.此纹波补偿方案在不增加任何IC外围元件的条件下,可增强系统稳定性且具有良好的瞬态响应性能.采用描述函数(DF)方法对所提出的纹波补偿方案进行小信号建模与稳定性分析.Simplis 仿真结果证明了所推导的系统模型与稳定性判据,实验结果进一步验证了理论分析.