Patent ID: 6970367
Filing Date: 2005-11-29
Classification: H02M,H05K

Abstract:
1. A switching power supply device comprising: a switching circuit for interrupting direct current to generate a pulse voltage; a transformer including a primary winding, a secondary winding, and a core for magnetically coupling the primary winding and the secondary winding; a multi-layer wiring board having wiring constituting the primary winding and the secondary winding; a rectifier circuit for rectifying an alternating current; a smoothing circuit for suppressing ripple; and a control circuit for controlling an output voltage from the smoothing circuit, the switching power supply device being for outputting a direct current obtained by applying the pulse voltage to a first connecting portion of the primary winding to induce an alternating current in a second connecting portion of the secondary winding, rectifying the alternating current by the rectifier circuit, and smoothing the alternating current by the smoothing circuit, wherein the multi-layer wiring board is provided with at least the switching circuit and the rectifier circuit and is arranged on a main wiring board, and the control circuit is arranged on the main wiring board.