Resonant converter and control circuit and control method thereof

Abstract

The invention discloses a resonant converter and a control circuit and a control method thereof. The resonant converter comprises a switching circuit and a resonance circuit, wherein the switching circuit has an upper switching tube coupled between an input voltage and a switching node and a lower switching tube coupled between the switching node and a reference ground. The control circuit comprises: a communication interface circuit, a storage circuit and a primary side switch control circuit, wherein the storage circuit provides a frequency setting signal according to a switching frequency set by a user; when the resonant converter is configured in an open-loop mode, and the primary side switch control circuit sets the frequencies of the first control signal and the second control signalaccording to the frequency setting signal, so that the frequencies of the first control signal and the second control signal are equal, and the conduction durations of the upper switching tube and the lower switching tube are controlled to be the same in one switch period and are both less than half of the resonance period of the resonance circuit.

Description

technical field [0001] The present invention relates to electronic circuits, and in particular, to a resonant converter and its control circuit and control method. Background technique [0002] In a resonant converter, a switching circuit converts a DC voltage into a square wave voltage and supplies it to a resonant circuit. The resonant circuit includes a resonant inductor and a resonant capacitor, and the resonant circuit has a resonant frequency determined by the inductance of the resonant inductor and the capacitance of the resonant capacitor. Usually, the switching frequency of the switching circuit is set equal to the resonant frequency to achieve zero current turn-off, thus reaching the best efficiency point. However, in practical applications, the inductance value of the resonant inductor and the capacitance value of the resonant capacitor may have a certain deviation from the theoretical value during design, so that the resonant converter cannot work at the best ef...

AI Technical Summary

Problems solved by technology

However, in practical applications, the inductance value of the resonant inductor and the capacitance value of the resonant capacitor may have a certain deviation from the theoretical value at the time of design, so that the resonant converter cannot work at the best efficiency point

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