Short-circuit protection circuit with current limiting function

Abstract

The present invention discloses a short-circuit protection circuit with a current limiting function. The short-circuit protection circuit comprises an overcurrent detection circuit, an N-channel enhancement MOS tube circuit, a delay control circuit and a short-circuit protection circuit. The overcurrent detection circuit is configured to detect the size of a current when power supply is performedfrom a large current direct current bus to a small current load; the N-channel enhancement MOS tube circuit can replace a fuse to have effects on restricting a short-circuit current and cutting off the short-circuit current; the delay control circuit is configured to allow a circuit to determine whether a direct current input current exceeds a current limiting value or not after the direct currentinput current is detected by the overcurrent circuit and send turning-off signals to the short-circuit protection circuit after duration exceeds limiting time; and the short-circuit protection circuit is electrically connected with the delay control circuit to receive signals sent by the delay control circuit, and if the delay control circuit sends the turning-off signals, the short-circuit protection circuit sends the turning-off signals to the N-channel enhancement MOS tube circuit to cut off a bus current and enters a dead lock state.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a short-circuit protection circuit with a current limiting function. Background technique [0002] At present, the switching power supply is widely used in various fields, and the reliability of the switching power supply is required to be higher and higher, and the volume is getting smaller and smaller. In order to ensure the stable and reliable operation of the switching power supply in different environments, it is necessary to design various protection functions. Among them, the current limiting protection function and the short circuit protection function are the functions that are given priority in the design. The switching power supply burns or damages the load due to the large internal power consumption. At present, the current limiting protection function and short circuit protection function are generally designed as automatic recovery mode to ensure t...

AI Technical Summary

Problems solved by technology

[0003] However, in a power supply line connected from a large current DC bus to a small current load, if the self-resetting fuse repeats the process of blocking the power supply and automatically releasing the power supply blocking state when the circuit and other components have not been sufficiently cooled, then Eventually, it will cause abnormalities in the self-resetting fuse itself, making it impossible to cut off the short-circuit current

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