LLC (Logical Link Control) series resonance converter and drive method thereof

Abstract

The invention discloses an LLC (Logical Link Control) series resonance converter and a drive method thereof. The LLC series resonance converter comprises a bridge circuit, a resonance circuit, a transformer and a rectifying circuit, wherein the bridge circuit is coupled to input voltage and comprises at least two first switches; the resonance circuit is coupled to the bridge circuit and driven by the first switches; the transformer is coupled to the resonance circuit; the rectifying circuit comprises two sub drive circuits which respectively comprise a second switch, a shut-off circuit and a pulse width processor; the second switches are coupled to two ends of a secondary side of the transformer and used for providing voltage output of the LLC series resonance converter; the shut-off circuits are used for providing shut-off signals for the second switches, and each shut-off circuit comprises a current transformer which is connected between the secondary side of the transformer and the two second switches in series and used for measuring the current of a source-drain electrode circuit branch, which flows through the second switches, to generate shut-off signals; and the pulse width processors are used for reducing the duty cycle of power switch drive signals of the primary side of the transformer at control ends of the first switches to obtain switch-on signals and provide the signals for the second switches.

Description

technical field [0001] The present invention relates to the communication field, in particular to an LLC series resonant converter and a driving method thereof. Background technique [0002] figure 1 It is a circuit diagram of an LLC series resonant converter composed of synchronous rectification transistors in the prior art, wherein the LLC series resonant converter 100 is mainly composed of a bridge circuit 110 , a resonant circuit 120 and a rectifying circuit 130 . The bridge circuit 110 adopts the control method of the symmetrical half bridge, the upper and lower tubes are complementary conduction, and the duty ratio is 50%; the resonant circuit 120 is composed of a resonant capacitor Cr, a resonant inductance Lr, and an excitation inductance Lm to form a resonant body, and Lr can be used as the leakage inductance of the transformer To make up; rectification circuit 130 is composed of a pair of synchronous rectification transistors Q1 and Q2 connected to the output capa...

AI Technical Summary

Problems solved by technology

[0017] The main purpose of the present invention is to provide an LLC series resonant converter and its driving method, to at least solve the above-mentioned problem of low reliability

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