Resonant converter and driving method thereof

A circuit for controlling a resonant converter, comprising:

• a first node to receive a first end voltage of a first synchronous rectification (SR) switch of the resonant converter;
• a second node to receive a second end voltage of a second SR switch of the resonant converter;
• a mode selector configured to detect at least one of the first and second end voltages, determine an operation region to be one of first and second regions in response to the detected end voltage, and generate a mode signal in response to a result of the determination;
• an SR controller configured to generate first and second SR drive control signals that adjust conduction duration of the first and second SR switches, respectively, when the result of the determination indicates that the operation region is the first region;
• and
• an SR driver configured to generate first and second gate control signals in response to the first and second SR drive control signals and output the first and second gate control signals to the first and second SR switches, respectively.

A method of controlling a resonant converter, comprising:

• detecting at least one end voltage of first and second synchronous rectification (SR) switches of the resonant converter;
• determining an operation region to be one of first and second regions in response to the detected end voltage;
• generating a mode signal in response to a result of the determination;
• and
• differently controlling conduction duration of the first and second SR rectification switches when the result of the determination indicates that the operation region is the first region.