Multiple-Output Power Supply Unit and Image Forming Apparatus Having the Power Supply Unit

摘要

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