Improved performance of flyback and ac/dc power converter system

A flyback converter comprising:

• i) a transformer including a primary side winding and a secondary side winding;
• ii) an input port coupled to a voltage source and connected to the primary side winding of the transformer;
• iii) a primary side switch arranged between the primary side winding of the transformer and the ground;
• iv) a secondary side switch arranged in series between the secondary side winding of the transformer and an output port;
• and
• v) a control unit;
• and in which the flyback converter is configured to implement;
• the method comprising the steps of:
• at the end of a switching cycle, before turning on the primary side switch:
• the control unit generating a Zero Voltage Switching (ZVS) pulse in the secondary side winding, such that the parasitic capacitor of the primary side switch is discharged;
• and
• consequently, turning on the primary side switch in ZVS or near ZVS conditions;
• in which the method includes the step of driving the secondary side switch combining a synchronous rectification signal, the ZVS pulse signal and a control pulse signal;
• in which, when the synchronous rectification signal is high, the secondary switch conducts current from its source terminal to its drain terminal, transferring power from the transformer to an output capacitor, and when the control pulse signal is high, the switch conducts current from its drain terminal to its source terminal, reflecting power from the output capacitor to the transformer;
• and in which the method includes the step of adjusting a power delivered to the output of the flyback converter by adjusting the duration of the control pulse signal.