Surge suppression circuit

Abstract

The invention provides a surge suppression circuit which comprises a first resistor, a first switching tube and a second switching tube, wherein the first end of the first resistor is connected with the negative output end of a rectifier in a power factor correction circuit, and the second end of the first resistor is grounded; the first end and the second end of the first switching tube are respectively connected with the first end and the second end of the first resistor, the control end of the first switching tube is connected with the first end of the first switching tube through a secondresistor and is connected with the first end of the second switching tube through a third resistor; and the second end of the second switching tube is connected with a controller through a fifth resistor, the control end of the second switching tube is grounded, the second end of the second switching tube is connected with the control end of the second switching tube through a fourth resistor, and the second end of the second switching tube is also connected with the control end of the second switching tube through a first capacitor.

Description

technical field [0001] The invention belongs to the field of switching power supplies, in particular to a surge suppression circuit applied to a power factor correction circuit. Background technique [0002] Switching power supply is more and more widely used in the power supply field because of its high efficiency and high power density. In order to meet the requirements of power factor and harmonic content, the current switching power supply needs to be equipped with a PFC (Power Factor Correction, power factor correction) circuit. After being installed in the switching power supply, the AC-DC converter in the PFC circuit will generate an excessive surge current when it is started, and it is necessary to take appropriate measures to suppress the surge current. [0003] The current method of suppressing the surge current is to serially insert a suitable surge suppression resistor in the loop of the PFC circuit to reduce the size of the surge current, and then the surge sup...

AI Technical Summary

Problems solved by technology

[0003] The current method of suppressing the surge current is to serially insert a suitable surge suppression resistor in the loop of the PFC circuit to reduce the size of the surge current, and then the surge suppression resistor connected in series in the loop will consume power. After the PFC works normally It will reduce the conversion efficiency of the PFC circuit. In order to prevent this phenomenon, the surge suppression resistor is short-circuited when the PFC circuit is working normally to improve the conversion efficiency of the PFC circuit.

In order to short-circuit the surge suppression circuit, an easier solution is to connect an electronic switch in parallel at both ends of the surge suppression resistor, and connect the surge suppression resistor to the negative output terminal of the PFC circuit, but when a surge current is generated , the two ends of the electronic switch are subject to a very high peak voltage, resulting in a high voltage difference between the reference ground terminal of the control circuit and the electronic switch control stage, resulting in breakdown of the electronic switch and damage to the electronic switch

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