Multi-path output flyback power supply with output short-circuit protection function and protection method

Abstract

The invention discloses a multi-path output flyback power supply with an output short-circuit protection function. The power supply comprises a transformer, a main switch, a pulse width modulation (PWM) control circuit, an output rectifier filter circuit and an output short-circuit protection circuit, wherein the transformer is provided with a primary winding and a plurality of secondary windings; the main switch is connected with the primary winding of the transformer; the PWM control circuit controls the main switch; the output rectifier filter circuit is connected with the secondary windings of the transformer and a load; and the output short-circuit protection circuit is connected with the output rectifier filter circuit, and comprises an operational amplifier, a metal oxide semiconductor (MOS) tube, a first resistor, a second resistor, a third resistor, a first capacitor and a power circuit for providing working power and reference voltage for the operational amplifier. The invention also discloses a short-circuit protection method for the flyback power supply. According to the output short-circuit protection circuit and the short-circuit protection method, a short-circuit protection function for each path of output of the flyback power supply can be independently realized, namely influence on the working state of other output circuits is avoided even though the output of one path is short-circuited.

Description

technical field [0001] The invention relates to a protection circuit, in particular to a multi-channel output flyback power supply with an output short-circuit protection function and a protection method. Background technique [0002] In many fields such as industrial automation control, switching power supply is used more and more widely, and its reliability is also more and more important. In order to meet the requirements of high reliability, a variety of protection functions must be integrated in the switching power supply. Among the various protection functions of switching power supplies, short-circuit protection (or over-current protection) is an extremely important function to ensure the reliability of electronic products. When the switching power supply is short-circuited, the semiconductor power device will flow a very large current, which will cause the power device to be damaged due to the large current flow or excessive temperature rise. At the same time, when...

AI Technical Summary

Problems solved by technology

For a switching power supply with multiple output DC voltages at the same time, as long as one output is short-circuited, it will affect the normal operation of other output power supplies

For the core control part of the equipment, its power supply must be very stable, otherwise it will cause serious loss or personal injury

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