Controller and control method of asymmetric half-bridge power supply

The invention provides a controller and a control method of an asymmetric half-bridge power supply, and relates to the technical field of electronics, the asymmetric half-bridge power supply comprises a first arm switch and a second arm switch which form a half bridge, and the asymmetric half-bridge power supply comprises a resonant circuit connected to the half bridge, the resonant circuit comprises a transformer and an oscillation capacitor, and the method comprises the following steps: providing a length parameter which reflects second turn-on time of a second arm switch in a previous switching period; providing a control signal to turn on the first arm switch for a first turn-on time within the current switching period; detecting whether the first arm switch realizes ZVS in response to the signal edge of the control signal, and adjusting the length parameter according to the ZVS; determining second turn-on time of the second arm switch in the current switching period according to the adjusted length param