Switching power supply capable of resisting 20 KV lightning strokes

Abstract

The invention relates to a switching power supply capable of resisting 20 KV lightning strokes. The switching power supply mainly comprises a lightning resistant surge circuit and a main circuit of the switching power supply, wherein the lightning resistant surge circuit comprises a voltage dependent resistor VR1, a thermistor NTC, a fuse F1, a common mode filtering noise inductor L1 which are connected in series sequentially to form a loop; the front end of the inductor L1 is connected in parallel with the series circuit of resistors (R23 and R24), and is connected in parallel with the a capacitor CX; the rear end of the inductor L1 is connected in parallel with small-dimension voltage dependent resistor VR2; resistors (R26 and R27) are connected in parallel with two ends of the inductor L1; the rear end of the lightning resistant surge circuit is connected with a rectifying module of the main circuit; the transformer unit of the main circuit is used for reducing leakage current on between the primary side and the secondary side of the power supply according to an internal shielding method and an external shield method. The switching power supply can resist the 20 KV lightning strokes, and the lightning resistant surge circuit can effectively protect the power supply without impacting stable output of the power supply.

Description

technical field [0001] The invention relates to the field of switching power supplies, in particular to a switching power supply capable of resisting 20KV lightning strikes. Background technique [0002] With the popularity of various household electronic products, the application of switching power supply is becoming more and more extensive, and the market has higher and higher requirements for switching power supply. The design of ordinary switching power supply cannot meet the market requirements in terms of lightning protection, and most of them can only meet the requirements of the market. 6KV lightning strike flow test, some products do not even meet the minimum 1KV requirement, most of the switching power supplies sold on the market entered the market without passing the surge test, and did not take effective protection measures against lightning strike surge, through the research of market users Facts have proved that, such as TV set-top box power supply, TV, DVD and...

AI Technical Summary

Problems solved by technology

[0002] With the popularization of various household electronic products, the application of switching power supply is more and more extensive, and the market requirements for switching power supply are also getting higher and higher. The design of ordinary switching power supply can not meet the market requirements in terms of lightning protection, and most of them can only meet the requirements of the market. 6KV lightning strike flow test, some products do not even meet the minimum 1KV requirement, most of the switching power supplies sold in the market entered the market without passing the surge test, and did not take effective protection measures against lightning strike surge, through the research of market users Facts have proved that, such as TV set-top box power supply, TV, DVD and other equipment, in harsh areas where lightning is frequent, such as summer lightning season, high-voltage surges enter the grid and enter the L and N terminals of the switching power supply, causing some switching power supply failures. If it is damaged, it will not work, which will affect the use of household and industrial equipment, and also cause certain hidden dangers. It will often cause damage to the power supply first, causing the equipment to fail to work, and the life is short, which cannot meet the needs of various industries and people's living equipment.

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