Patent ID: 8059433

Claim:
A power circuit comprising: a first rectifying and filtering circuit configured to receive an alternating current (AC) voltage and transform the AC voltage to a first DC voltage, the first rectifying and filtering circuit comprising a first output configured to output the first DC voltage and a first filter capacitor directly connected between the first output and ground; a power factor correction (PFC) circuit comprising a first transformer, a first diode, a second diode with a grounded positive terminal and a first storage capacitor, the first transformer comprising a primary winding and a secondary winding; an inverter circuit comprising a transistor and a second transformer, the second transformer comprising a primary winding and a secondary winding, the primary winding of the second transformer being grounded via the transistor and configured to receive the first DC voltage via the primary winding of the first transformer, the first diode, and the secondary winding of the first transformer in series when the transistor is switched on; and a second rectifying and filtering circuit connected to the secondary winding of the second transformer for providing a second DC voltage to a load circuit; wherein the first filter capacitor is charged via a current path formed by the primary winding of the first transformer, the second diode, and the first filter capacitor when the transistor is switched off.