Snubber circuit and buffering method for snubber circuit

Abstract

A snubber circuit includes a capacitor and a buffer device. The buffer device has a first terminal and a second terminal. The first terminal is electrically connected to the capacitor. When the buffer device operates in a first conduction mode, a charge current flows from the second terminal to the first terminal through the buffer device. When the buffer device switches from the first conduction mode to a second conduction mode, the buffer device generates a discharge current which flows from the first terminal to the second terminal through the buffer device over a specific period of time, such that after the buffer device enters the second conduction mode, a relative maximum voltage level appearing first at the second terminal is lower than a voltage level at the first terminal.

Description

technical field

[0001] The invention relates to a snubber circuit, in particular to a snubber circuit with long recovery time under high-speed switching and a related snubber method for the snubber circuit. Background technique

[0002] figure 1 A conventional DC-to-DC converter (flyback converter) 100 for a switching power supply is shown, wherein the leakage inductance of the transformer TX1 will cause Voltage spike across switch Q1. The DC-DC converter 100 utilizes an RCD snubber circuit (RCD sunbber) 102 composed of a plurality of resistors RX and R1, a capacitor C1, and a diode D1 to reduce the instantaneous switching primary side circulating current Id, wherein the resistor R1 is an optional component. The RCD snubber circuit 102 charges the primary circulating current Id into the capacitor C1 through the diode D1. Since the recovery time / reverse current time (recovery time) of the diode D1 is too short, the capacitor C1 cannot be completely discharged through the d...

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