Start-up control circuit and resonant converter

Abstract

The application is suitable for the technical field of resonant converter, and provides a start-up control circuit and a resonant converter. The start-up control circuit comprises a feedback module, a comparison and selection module and a logic operation module. The comparison and selection module is electrically connected with the feedback module and the logic operation module. The feedback module is used for being electrically connected with an output end of a resonant conversion circuit in the resonant converter. The logic operation module is used for being electrically connected with a driving circuit in the resonant converter. The start-up control circuit provided by the application can build a gradually expanded resonant capacitor voltage constraint threshold along the start-up process, realizes the smooth establishment of the resonant capacitor DC bias, limits the fluctuation amplitude of the resonant capacitor voltage, avoids the problem that the bus voltage full voltage is applied to the resonant inductor in the traditional scheme, and finally effectively suppresses the resonant current peak value in the start-up stage, reduces the impact of the current stress on the core devices such as the switch tube and the resonant inductor.

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