Patent ID: 8587970

Claim:
An isolated switching power supply apparatus comprising: a power factor correction converter including: a voltage input unit arranged to receive a voltage of a commercial power supply; a rectifier circuit arranged to rectify the commercial power supply voltage received by the voltage input unit; at least one boost converter circuit that is connected to a latter stage of the rectifier circuit and includes an inductor, a switching element, and a rectifying element; a smoothing circuit connected to a latter stage of the boost converter circuit; and a switching controller arranged to on/off control the switching element so that input current received from the commercial power supply has a shape similar to a shape of the commercial power supply voltage; a transformer including at least isolated primary and secondary windings; a switching circuit arranged to switch a voltage to be applied to the primary winding by the smoothing circuit; a secondary-side rectifying smoothing circuit arranged to rectify and smooth an alternating-current voltage generated in the secondary winding; a voltage output unit arranged to output a voltage obtained by the secondary-side rectifying smoothing circuit; a secondary-side output voltage detector arranged to detect a voltage obtained by the secondary-side rectifying smoothing circuit; a primary-side digital control circuit that is disposed on the primary side of the transformer and includes a switching controller arranged to control on/off operation of at least one of the boost converter circuit and the switching circuit; a secondary-side digital control circuit that is disposed on the secondary side of the transformer, is arranged to receive the voltage detected by the secondary-side output voltage detector, and includes a feedback controller arranged to generate a feedback signal to control the switching circuit; and an isolated signal transmitter arranged to perform serial communications between the primary-side and secondary-side digital control circuits while maintaining isolation therebetween.