Single mosfet flyback supply help

Thread Starter


Joined Apr 16, 2012
I am looking for some information on flyback converters that use only a single Mosfet as self oscillator and output.
I am trying to understand better this type of circuit as I have a faulty computer power supply as a test subject, this seems to be a single Mosfet linked to a transformer with two output windings of say 7.5v (for 5v stby) and 15v (for the KA3511) (guesswork on actual voltages) and an aux winding for regulation purposes.
It is under control by this aux winding producing a negative voltage for gate control after being kick started by a high value resistor from a mains created DC voltage (240v rms).
There is No infra red feedbacksystem in this design just what seems to be a self oscillator design, although there may be some frequency sync with a KA3511 ic when its powered up to drive the main power section switch devices.
Can anyone point me to some circuits and explanation please.
Many Thanks from David