Resonance converter and synchronous rectification driving method thereof

A resonance converter, comprising:

• a switch circuit having at least one bridge circuit comprising two first switches;
• a resonance circuit coupled to the switch circuit and having a resonance frequency;
• a transformer having a primary side coupled to the resonance circuit and a secondary side;
• a full-wave rectification circuit coupled to the secondary side of the transformer and having two second switches wherein each of the second switches has a drain and a source and a channel resistance voltage is generated when a current flows through the drain and the source;
• and
• a synchronous rectification driving circuit coupled to the switch circuit and the full-wave rectification circuit, wherein:
• when an operating frequency of the resonance converter is less than the resonance frequency and the resonance converter is coupled to a heavy load, the channel resistance voltage is compared with a reference voltage by the synchronous rectification driving circuit for driving the second switches of the full-wave rectification circuit;
• and
• when the operating frequency of the resonance converter is not smaller than the resonance frequency, duplicated signals of signals used to drive the first switches are respectively used by the synchronous rectification driving circuit to drive the corresponding second switches of the full-wave rectification circuit.