Resonant converter, power supply and power controlling method thereof

A resonant converter comprising:

• a square wave generator configured to alternately turn on and off first and second switches according to a frequency to generate a square wave;
• a resonant wave generator configured to generate a resonant wave corresponding to the square wave;
• a rectifier configured to output a voltage corresponding to the resonant wave;
• and
• a controller configured to control a frequency modulation of the resonant converter, wherein the controller comprises a variable switching circuit configured to increase the frequency of the resonant converter in response to the resonant converter entering a capacitive mode.

A power supply for compensating for system overload by increasing the frequency of a resonant converter, the power supply comprising:

• a resonant converter comprising:
• a controller configured to control a frequency modulation of the resonant converter, the controller being configured to increase a frequency of the resonant converter in response to the resonant converter entering a capacitive mode,
• wherein under normal operation, the power supply operates in an inductive mode under zero voltage switching, and during overload the power supply operates in the capacitive mode, and
• wherein, upon the power supply operating in a capacitive mode, the controller is configured to increase the frequency of the resonant converter in order to place the resonant converter into inductive mode.