一种用于Buck变换器的过流保护电路  

An Over-Current Protection Circuit Applied in Buck Converter

作　　者：高峡[1] 冯全源[1] 

机构地区：[1]西南交通大学微电子研究所,成都611756

出　　处：《微电子学》2017年第3期359-362,共4页Microelectronics

基　　金：国家自然科学基金资助项目(61531016;61271090);四川省科技支撑计划资助项目(2015GZ0103)

摘　　要：基于功率MOS管导通电阻对电流采样的方法,设计了一种用于带集成功率MOS管的Buck变换器的过流保护电路,改善了传统过流保护电路的限流阈值随电源电压和温度变化较大的问题。对该电路的结构和原理进行了阐述与理论推导,采用Hspice软件对理论分析进行了仿真验证。仿真结果表明:当电源电压在2.5~6V、温度在-55℃~125℃的范围内变化时,电路的限流阈值保持在3.2A,限流阈值的最大误差值不超过±9.4%。该电路具有极快的响应速度,最大延时仅为33ns。Based on the method of current-sensing via the on resistance of power MOSFET, an over-current protection circuit was proposed for the buck converters that integrated the power MOSFETs. The problem of the current limit threshold changing with the supply voltage and the temperature in traditional over-current protection circuits was alleviated. The proposed circuit structure was explained and derived in theory. The Hspice simulation tool was used to verify the theoretical analysis. The simulation results showed that the current limit threshold maintained at 3.2 A and its maximum error was less than ±9.4% when the supply voltage range was 2.5-6 V and the temperature range was -55 ℃ -125 ℃. The proposed circuit had a very rapid response rate, and the maximum delay time was only 33 ns.

关 键 词：过流保护 BUCK变换器 功率MOS管 导通电阻 

分 类 号：TN433[电子电信—微电子学与固体电子学]