关键词: 本安电源, 短路过流保护, 自恢复, 软启动

Abstract: This article proposes a new type of protection circuit for intrinsic safety power supplies in order to address the safety issues of overcurrent and short circuit. The circuit replicates the main circuit current by a certain proportion through a current mirror circuit, and samples the current signal through the secondary circuit. After amplification and offset processing, the signal is input to the negative input terminal of a comparator, while the positive input terminal is connected to the short-circuit detection signal. When the power supply load experiences overcurrent or short-circuit faults, the hysteresis comparator outputs an overcurrent or short-circuit control signal, quickly turning off the main current switch and thereby protecting the load from the main circuit. At the same time, the microcurrent switch is activated to detect whether the short-circuit fault has been eliminated, so that the main current switch circuit can automatically recover after the fault is eliminated. In addition, the soft start circuit of the power protection circuit is used to solve the problem of overcurrent protection false triggering that may be caused by surge current during the power startup process.