A switching power supply and its short-circuit protection method

Abstract

The invention provides a switching power source and a short-circuit protection method thereof. According to the switching power source and the short-circuit protection method thereof, a power conversion circuit carries out chopped wave conversion and power transfer on received input voltage through the switching on and switching off of a switch tube in the power conversion circuit; when an output short-circuit fault occurs on the switching power source, a short-circuit detection circuit can fast detect the output short-circuit fault and generate output short-circuit detection signals; a sampling feedback circuit generates and outputs feedback signals according to the short-circuit detection signals; a power source chip limits PWM signals outputted to the switch tube by the output end of the power source chip according to the feedback signals, so that quick execution of short circuit protection can be realized; when power source signals received by the power source end of the power source chip fall to a preset under-voltage protection point, the switching power source enters a hiccup protection mode, so that a short-circuit protection function is reliably realized; and based on the fast and reliable short-circuit protection, when an output short-circuit fault occurs on the switching power source, stress increase of the key components of the switching power source can be effectively restrained.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a switching power supply and a short-circuit protection method thereof. Background technique [0002] A switching power supply is an AC-DC or DC-DC conversion unit that is widely used in industrial fields due to its high efficiency, small size, and high reliability. The switching power supply is mostly used as the auxiliary power supply unit of the system, and its working stability and reliability are very important. [0003] In the actual working process, the output of the switching power supply will have abnormal faults such as overcurrent, short circuit, and overvoltage. The device is damaged. Especially when the output of the switching power supply has a sudden short-circuit fault, the output current of the switching power supply at the moment of the short circuit is very large, which will cause higher stress on the key components of the switching power sup...

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Problems solved by technology

[0005] In view of this, the present invention provides a switching power supply and its short-circuit protection method to solve the problem of slow response speed of short-circuit protection in the prior art

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