Flyback switching power supply with output short circuit protection function

Abstract

The invention discloses a flyback switching power supply with the output short circuit protection function. The flyback switching power supply with the output short circuit protection function comprises a control chip and a switching circuit, wherein the switching circuit comprises a transformer and a switching unit, the control chip is used for controlling the switching unit so that energy storage and transmission can be achieved. The flyback switching power supply with the output short circuit protection function further comprises a starting current-limiting circuit and a leading edge blanking circuit, wherein the starting current-limiting circuit is connected between a direct-current input power supply and the control chip, the leading edge blanking circuit is connected with the control chip and the switching unit, the starting current-limiting circuit is used for controlling the voltage provided for the power supply end of the control chip to be within a preset voltage range so as to reduce the starting current existing when the control chip starts to work, and the leading edge blanking circuit is used for eliminating the first peak sent to the current sampling end of the control chip by primary side current of the transformer at the moment the switching unit is turned on. The flyback switching power supply with the output short circuit protection function has the advantage that short circuit protection of any output voltage can be achieved under the condition of high voltage, wide-range input and multi-path output voltage of the flyback switching power supply through the combination of the leading edge blanking circuit and the starting current-limiting circuit.

Description

technical field [0001] The invention relates to the field of power electronics, more specifically, to a flyback switching power supply with an output short-circuit protection function. 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. The flyback switching power supply is used as an auxiliary power supply to supply power to electronic products, and its output short-circuit protection performance has become particularly important. like figure 1 As shown, it is a schematic diagram of an existing flyback switching power supply. When the output voltage is short-circuited, the common practice is to reduce the duty cycle of the output of the control chip, and then cut off the power supply of the control chip U1 to realize hiccup protection. Since the voltage of the primary current of the transformer T1 on the sampling resistor Rs is filtered...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is that in the above-mentioned high-voltage, wide-range input and multi-channel output flyback switching power supply system of the prior art, when the output voltage is short-circuited, it is difficult to protect the switching power supply, and it is easy to cause the output device to be damaged. To overcome the defects of overheating failure, provide a flyback switching power supply with output short circuit protection function

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