Power convertor

A power supply circuit comprising:

• a push-pull portion comprising a transformer having a primary winding and a plurality of secondary windings, wherein a first terminal of the primary winding is connected to ground via a first switch, and wherein a second terminal of the primary winding is connected to ground via a second switch;
• an inductor having a first terminal thereof connected to an input voltage via a third switch, wherein a second terminal of the inductor is connected to a centre tap on the primary winding of the transformer;
• an energy storage portion connected between the primary winding of the transformer and ground, said energy storage portion being further connected to the first terminal of the inductor via a fourth switch, wherein the first, second, third and fourth switches have respective control terminals;
• and
• a plurality of output portions, each comprising first and second output terminals and arranged to provide a respective output voltage across said first and second output terminals, wherein a first terminal of each secondary winding is connected to the first output terminal of a corresponding output portion via a respective first forward bias output diode, a respective second terminal of each secondary winding is connected to the respective first output terminal via a respective second forward bias output diode, and wherein the respective second output terminal is connected to a centre tap of the respective secondary winding.