Patent ID: 7755914

Claim:
A power supply apparatus comprising: a converter circuit comprising a primary switching element and an auxiliary switching element, the auxiliary switching element for transferring a reflected voltage signal; a transformer comprising a primary and a secondary, the primary coupled with the converter circuit, the primary comprising a single winding and the secondary comprising a single winding; an output rectifier circuit coupled with the secondary of the transformer; and a resonant circuit included in the converter circuit, the resonant circuit being coupled with the primary, the resonant circuit comprising one or more resonance capacitors, the one or more resonance capacitors configured for providing a transformer resonance, the transformer resonance comprising the reflected voltage signal, the capacitance of the one or more resonance capacitors and a parasitic capacitance of the transformer, the reflected voltage signal received at the resonant circuit via the auxiliary switching element coupled to the primary, the reflected voltage signal being reflected from the secondary to the primary, the resonant circuit converting a pulse train to produce a voltage potential, the voltage potential varying in proportion to an output voltage, the pulse train comprising a duty cycle proportional to a load current.