一种宽负载高效率Buck转换器设计  

A Wide Load High Efficiency Buck Converter Design

作　　者：何泽楚 曹先国 姚佳 李涛 李青鸿 王良彬 HE Ze-chu;CAO Xian-guo;YAO Jia;LI Tao;LI Qing-hong;WANG Liang-bin(College of Automation and Information Engineering,Sichuan University of Science and Engineering;Sichuan Xinsheng Xinguo Technology Co.,Ltd.)

机构地区：[1]四川轻化工大学自动化与信息工程学院 [2]四川芯盛芯国科技有限公司

出　　处：《中国集成电路》2023年第12期45-50,共6页China lntegrated Circuit

摘　　要：本文提出了一种双模式调制技术,以提高宽负载范围内降压型DC-DC转换器的转换效率。采用自适应导通时间电路(AOT)和斜坡信号VRAMP产生电路来维持转换器连续导通时间(CCM)工作模式下开关频率基本稳定;利用过零检测电路来检测电感电流,当电感电流过零时,能及时关断续流管,降低开关损耗,进一步提升轻载转换效率。该DC-DC基于SMIC 0.18 um BCD工艺进行电路仿真验证,该电路可在0~3A宽负载范围内正常工作,在输入电压3~5V范围内,PFM模式下输出电压纹波小于5.2mV,1m A负载下转换效率为87.37%。在PWM模式下输出电压纹波小于2.8mV,3A负载下最低转换效率为84.24%。峰值效率可达94.91%,全负载范围内转换效率大于84%。In this paper,a dual-mode modulation technique is proposed to improve the conversion efficiency of a step-down DC-DC converter over a wide load range.An adaptive on-time circuit(AOT)and a ramp signal VRAMP generation circuit are used to maintain the switching frequency basically stable in the continuous conduction time(CCM)operating mode of the converter;an over-zero detection circuit is utilized to detect the inductor current,so that the continuity tube can be turned off in time to reduce the switching loss when the inductor current is over zero,which further improves the conversion efficiency in light loads.The DC-DC is based on SMIC 0.18 um BCD process for circuit simulation verification,the circuit can work normally in a wide load range of 0~3A,in the input voltage range of 3~5V,the output voltage ripple is less than 5.2mV in PFM mode,and the conversion efficiency is 87.37%under 1mA load.In PWM mode,the output voltage ripple is less than 2.8mV,and the minimum conversion efficiency is 84.24%under 3A load.Peak efficiency is up to 94.91%,and conversion efficiency is greater than 84%over the full load range.

关 键 词：PWM/PFM调制 开关频率 过零检测 转换效率 

分 类 号：TM46[电气工程—电器]