Switch power supply with fault protection function and control method thereof

Abstract

The invention discloses a switch power supply with a fail safe function and a control method thereof. The switch power supply comprises an energy storage unit, a switch, a control circuit, a fault detection circuit and a fault timing circuit, wherein, the energy storage unit can store energy; the switch is connected to the energy storage unit by electric coupling; when the switch is turned on, the energy storage unit stores energy, and when the switch is turned off, the energy stored in the energy storage unit is transmitted to load; the control circuit is connected to the switch by electric coupling so as to generate a control signal to control the turn on and the turn off of the switch; the fault detection circuit detects whether the switch power supply is in fault or not; the fault timing circuit is connected to the in fault detection circuit and the control circuit by electric coupling, times the continuous fault state, and shields the control circuit when the timing exceeds the first preset time so as to enable the control signal to turn off the switch.

Description

technical field [0001] The invention relates to a switching circuit, in particular to a switching power supply with a fault protection function. Background technique [0002] Many electronic devices today require a DC supply voltage, which usually comes from an adapter. The adapter obtains AC voltage from the wall socket (grid), converts the AC voltage into an uncontrolled DC voltage through a rectifier bridge, and converts the uncontrolled DC voltage into the required DC power supply voltage through a switching power supply. [0003] Switching power supplies usually use transformers or inductors as energy storage elements. For example, a transformer is used as an energy storage element in a flyback converter. A switch is electrically coupled to the primary side of the transformer, and the control circuit controls the switch to be turned on and off, so that energy is alternately stored or transmitted in the transformer. to the secondary side of the transformer. The second...

AI Technical Summary

Problems solved by technology

However, when the switching power supply is just started, the output voltage is less than the threshold because it has not been established, and the switching power supply will be considered overloaded and will be shut down immediately, resulting in the failure of the switching power supply to start normally.

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