【摘要】 针对大功率负载的电源管理芯片容易出现过载、短路问题,提出一种利用采样电流转化为采样电压的限流模式折返保护电路。该电路限流环路利用缓冲器双支路实现实时控制,其工作状态随输入电压有所转变,hspices仿真实验验证了该电路限流值稳定,基本不随着电源电压的变化而变化,而且芯片的短路功耗降低60%。采用联华电子公司0.5μm 5 V的CMOS工艺线在低压差线性稳压器(LDO)中进行了投片验证,实测芯片常值限流200 mA、折返限流80 mA,自身静态电流极低仅2μA左右。投片测试结果表明,该电路起到保护作用的同时,符合现代电源管理芯片对高效率低功耗的要求。更多还原

【Abstract】 A new circuit that transfer sensing current into sensing voltage under a current limiting mode with fold-back protection system, is presented in this paper, implemented in 0 5μm 5V CMOS process and verified by Ca-dence and Hspice simulation. Experimental result verifies that the maximum current limit of the proposed LDO is setto be 200 mA, and the foldback current limit is 80 mA. Thus, the power consumption of the chip can be saved up to60% at the foldback circuit condition, which also decreases the risk of damaging the power transistor and makes itwidely used in all kinds of power management of microprocessors, moreover, the circuit features simple structureand low quiescent power consumption.更多还原