Power converting device

A power converting device comprising:

• a transformer including a primary winding for receiving an input voltage, and a secondary winding which generates an induced voltage in response to induction associated with receipt of the input voltage by said primary winding;
• a first switch which has a first end coupled electrically to one end of said primary winding, a grounded second end, and a control end;
• a pulse-width modulation (PWM) controller which is coupled electrically to said control end of said first switch, which generates a first PWM signal for controlling conduction and non-conduction of said first switch, and which generates a control signal that leads the first PWM signal;
• a rectifier-filter circuit which is coupled electrically to a first end of said secondary winding and which rectifies the induced voltage so as to generate a direct-current (DC) output voltage;
• a second switch which has a control end, a first end coupled electrically to said rectifier-filter circuit, and a second end that is coupled electrically to a second end of said secondary winding;
• and
• asynchronous rectifier controller which is coupled electrically to said second switch for controlling conduction and non-conduction of said second switch, and which receives the control signal generated by said PWM controller, so as to control, according to the control signal, said second switch to become non-conductive prior to conduction of said first switch.