一种适用于大电流DC-DC高精度电流采样电路  

A high accuracy current sampling circuit suitable for high current DC-DC

作　　者：杨子航 徐卫林[1] 韦雪明[1] YANG Zihang;XU Weilin;WEI Xueming(Guangxi Key Laboratory of Precision Navigation Technology and Application,Guilin University of Electronic Technology,Guilin 541004,China)

机构地区：[1]桂林电子科技大学广西精密导航技术与应用重点实验室

出　　处：《桂林电子科技大学学报》2019年第1期17-21,共5页Journal of Guilin University of Electronic Technology

基　　金：广西自然科学基金(2017GXNSFAA198224)

摘　　要：为了提高电流采样精度,基于0.5μmBCD工艺,提出了一种应用于降压型DC-DC变换器的电流采样电路。通过增加补偿电流的方法,使功率管中的电流与电感中的电流相等,从而降低了采样误差。仿真结果表明:当电感电流为7A时,所提出的电路采样精度为99%,比传统结构高2.5个百分点;当电感电流IL∈(0,7A)时,采样精度始终大于99%。与传统结构相比,所提出的电路采样精度随温度和输入电压变化更小,实现了高精度稳定采样,适用于大电流的DC-DC变换器。In order to improve the current sampling accuracy,based on 0.5μm BCD process,a current sampling circuit applied to a step-down DC-DC converter was proposed.By increasing the compensation current method,the current in the power tube is equal to the current in the inductor,thereby reducing the sampling error.Simulation results show that when the inductor current is 7 A,the sampling accuracy of the proposed circuit is 99%,which is 2.5 percentage points higher than that of the conventional structure.When the inductor current is I L∈(0,7 A),the sampling accuracy is always greater than 99%.Compared with the traditional structure,the proposed circuit sampling accuracy changes with temperature and input voltage is smaller,and achieves high-precision stable sampling,suitable for large-current DC-DC converters.

关 键 词：DC/DC变换器 电流采样 高精度 电流补偿 

分 类 号：TN402[电子电信—微电子学与固体电子学]