Active clamp flyback converter and control ic

A control IC comprising an active clamp flyback converter comprising:

• a main switch;
• a primary winding that is electrically connected in series with the main switch;
• a clamp switch that is electrically connected to a connection point between the main switch and the primary winding;
• a clamp capacitor that is connected in series with the clamp switch;
• and
• a controller that is electrically connected to the main switch and the clamp switch and outputs a first ON signal to control the main switch and a second ON signal to control the clamp switch during a period when the main switch is off, wherein
• the controller outputs the second ON signal during a half cycle or more of a resonance period, in which a resonance current flowing in a resonance circuit comprising the clamp capacitor and a leakage inductance generated when the clam switch is turned on is limited by an excitation current of an excitation inductance of the primary winding.