Patent ID: 8814327

Claim:
A apparatus comprising: a transformer having a primary winding, a first secondary winding, and a second secondary winding; a first DC voltage generation unit configured to generate a first DC voltage from a voltage generated by the first secondary winding; a second DC voltage generation unit configured to generate a second DC voltage from a voltage obtained by adding a voltage generated by the second secondary winding on the first DC voltage; a switching unit configured to energize the primary winding; a control unit, including a voltage input node, configured to control the switching unit so that a voltage input to the voltage input node becomes constant such that the first DC voltage and the second DC voltage are fed back with feedback factors corresponding to degrees of contribution of the first DC voltage and the second DC voltage to feedback control, the voltage input node being connected to an output node of the first DC voltage generation unit and an output node of the second DC voltage generation unit via resistors, respectively; and a change unit configured to receive change an input control signal and relatively change the feedback factors according to the input control signal.