一种外部可调折返式LDO过流保护电路  

An Externally Adjustable Foldback Current-Limit Circuit for LDO

作　　者：刘雷 罗萍[1] 赵忠 刘俊宏 杨秉中 LIU Lei;LUO Ping;ZHAO Zhong;LIU Junhong;YANG Bingzhong(State Key Lab.of Elec.Thin Films and Integr.Dev.,Univ.of Elec.Sci.and Technol.of China,Chengdu 610054,P.R.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,成都610054

出　　处：《微电子学》2021年第5期636-640,共5页Microelectronics

基　　金：预研项目(1126190601A)。

摘　　要：基于0.18μm BCD工艺,提出了一种外部可调、带限流的折返式LDO过流保护电路。该电路同时具有限流和折返功能。限流部分通过电流镜构成的环路箝位最大输出电流,折返部分通过误差放大器构成的负反馈环路产生与输出电压成比例的电流折返输出电流。与传统过流限结构相比,新结构可降低功耗,保护功率管不被烧毁;与传统折返式结构相比,新结构可通过调节外部电阻方便地调节过流限与折返点电压,避免了稳压器的闩锁现象。在1.2V典型输出下,LDO电路的仿真验证结果表明,在调节四组不同的外部电阻值条件下,过流限范围为215~350mA,折返电压范围为450~900mV,输出短路时,功率管的功耗降至230mW。Based on a 0.18μm BCD process,an externally adjustable foldback current-limit circuit for LDO was proposed.This new circuit had both current limiting and foldback functions.The current limiting part clamped the maximum output through a loop formed by current mirrors.The foldback part used a negative feedback loop formed by an error amplifier to generate a current foldback output current proportional to the output voltage.Compared with traditional current-limit structures,this new structure saved a lot of power consumption and protected the power MOSFET from being burnt.Compared with the traditional foldback structures,this structure could easily adjust the current limit and the foldback point by adjusting two external resistors to avoid the voltage regulator from latching up.At 1.2Vtypical output,the simulation verification results of the LDO circuit showed that the current limit range was 215~350mA,and the foldback voltage range was 450~900mV while adjusting four different external resistance values.The power consumption during short-circuited region was reduced to 230mW.

关 键 词：线性稳压器 过流保护 外部可调 闩锁 

分 类 号：TN433[电子电信—微电子学与固体电子学]