一种适用于电流模BUCK电路的失控辅助电路  

An auxiliary circuit to prevent current mode BUCK from out-of-control

作　　者：李响[1] 王佳文 周泽坤[1] LI Xiang;WANG Jiawen;ZHOU Zekun(State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technologyof China,Chengdu 610054,China)

机构地区：[1]电子科技大学电子薄膜与集成器件国家重点实验室

出　　处：《电子元件与材料》2019年第7期76-79,共4页Electronic Components And Materials

基　　金：国家自然科学基金(61674025;61306035);中央高校基础研究基金(ZYGX2016J056);“气象信息与信号处理”省高校重点实验室基金(QXXCSYS201504;QXXCSYS201603)

摘　　要：在某些特殊的工作条件下,峰值电流模BUCK转换器会工作在输入电压和输出电压差值较小,且开关占空比较大的情况下。此时,如果发生负载由重载跳变到极轻载的变化,可能会导致输出电压高于输入电压的不利情况发生,整个控制环路出现失控,输出电压出现振荡波形。本文提出的辅助控制电路通过对输入、输出电压的比较检测,判断BUCK环路是否处于异常状态,并在合适的时间内关断高低侧功率管,保证了输出电压的稳定性。基于0.35μm CMOS工艺的仿真结果表明,当BUCK转换器负载发生重载6 A跳变为极轻载100 mA使得输出电压VO超过输入电压VIN时,失控辅助电路开始工作并在VO掉到VIN以下时及时输出恢复信号并关闭该辅助电路,恢复时间为87μs,整个过程未出现输出电压振荡现象。Under some special operating conditions,the peak-current mode BUCK converters operate with close input(V)IN and output(V)voltage and at large duty cycle.An unfavorable situation with higher output than the input voltage can be caused as O the load changes from heavy to an ultra-light one,leading to an out-of-control and oscillating output waveform.In this work,an auxiliary control circuit was proposed to determine whether it was abnormal by comparing the input and output voltage.The high-side and low-side tubes were then turned off accordingly to ensure the stability of the output waveform.The simulation result of the 0.35μm CMOS process shows that the auxiliary circuit starts to function when the BUCK converter load is changed from 6 A to 100 mA with V<V.The high-side and low-side power MOSFETs are then turned off until V falls below V.After that,the recovery IN O O IN signal is generated immediately to turn off the auxiliary circuit.The recovery time is 87μs,and no oscillation of output voltage is observed.

关 键 词：BUCK 电流模 负载跳变 振荡问题 

分 类 号：TN432[电子电信—微电子学与固体电子学]