Patent ID: 8472832

Claim:
A multiple-output power supply unit comprising: a transformer that includes: a primary winding; and a secondary winding which has a first node and a second node and which generates a secondary-side voltage at the secondary winding; a first output terminal that is connected to the first node so as to output a first voltage corresponding to the secondary-side voltage; a first constant voltage element that is connected to the first output terminal; a current limiting resistor that is provided between the first constant voltage element and the second node; a second constant voltage element that is provided between the second node and a ground; a second output terminal that is connected between the first constant voltage element and the current limiting resistor so as to output a second voltage different from the first voltage; a current generation circuit that is provided between the first node and the ground so as to cause a predetermined current to flow between the first node and the ground by the secondary-side voltage; a transformer driver circuit that is connected to the primary winding so as to drive the transformer; and a secondary-side voltage control circuit configured to control the transformer driver circuit so as to generate the secondary-side voltage having a predetermined value at the first node.