Abstract: The present invention discloses a control method and apparatus of resonant converter with low power loss at light load and standby. Based on the frequency response and loading condition of the resonant tank of a resonant converter, adjusts the switching frequency and the switching duty cycle to have a stable output voltage. Perform zero voltage switching and obtain higher converting efficiency by using the energy transfer in the resonant tank of the resonant type converter. Also have higher converting efficiency by combining with synchronize-rectify. Including: a resonant type converter, a controller of resonant type converter, and a regulated voltage mode (frequency modulation hybrid pulse width modulation, FMHYPWM) controller, and if the system specification require, a power factor correction or a double voltage rectifier circuit may be used in the advanced stage of the resonant type converter. The out put rectifier of the resonant type converter may be changed to a synchronized-rectifier.