LLC series resonant converter and the driving method for the synchronous rectification power switches thereof

An LLC series resonant converter, comprising:

• a bridge circuit, coupled to an input voltage, comprising at least one pair of power switches;
• a resonant network, coupled to the bridge circuit and being driven by the power switches;
• a transformer, coupled to the resonant network;
• a rectification circuit, coupled to the transformer, the transformer providing an output current of the LLC series resonant converter, wherein the rectification circuit comprises at least one pair of synchronous rectification power switches, the at least one pair of synchronous rectification power switches and the power switches of the bridge circuit have a mapping relation, corresponding one of the synchronous rectification power switches and corresponding one of the power switches are synchronously on or off;
• and
• a frequency adjustment controller, coupled between the power switches and the synchronous rectification power switches, providing driving signals to the synchronous rectification power switches in response to the operating frequency of the LLC series resonant converter and the series resonant frequency of the resonant network, to perform synchronous rectification in the LLC series resonant converter.