Switching power supply unit

Abstract

A switching power supply unit capable of simplifying its structure by reducing the number of parts for wiring is provided. A rectifier circuit has a diode inserted between a first secondary winding and a second secondary winding to form a series circuit therewith, and a diode inserted between a third secondary winding and a fourth secondary winding to form a series circuit therewith. A smoothing circuit has a first choke coil inserted between an input section connected to a center tap and an output terminal, and a second choke coil inserted between an input part connected to a junction point and an output terminal. A first path and a second path are formed of a wiring member made of a single sheet metal, and a third path and a fourth path are formed of a wiring member made of another sheet metal.

1 . A switching power supply unit comprising, on a substrate:
 a transformer transforming and outputting an AC voltage;   a rectifier circuit rectifying the AC voltage supplied from the transformer; and   a smoothing circuit smoothing and outputting the voltage rectified by the rectifier circuit,   wherein the transformer is disposed adjacent to both of the rectifier circuit and the smoothing circuit, and   the rectifier circuit is mounted on the substrate with an intermediate base in between.   
   
   
       2 . A switching power supply unit according to  claim 1  comprising a switching circuit converting a DC input voltage into an AC voltage and outputting the converted AC voltage to the transformer,
 wherein the switching circuit is mounted on the substrate with the intermediate base in between.   
   
   
       3 . A switching power supply unit according to  claim 2 ,
 wherein the switching circuit and the rectifier circuit are integrally mounted on the substrate with the intermediate base in between.   
   
   
       4 . A switching power supply unit comprising, on a substrate:
 a transformer transforming and outputting an AC voltage;   a rectifier circuit rectifying the AC voltage supplied from the transformer; and   a smoothing circuit smoothing and outputting the voltage rectified by the rectifier circuit,   wherein the rectifier circuit, the transformer, and the smoothing circuit are arranged in a line in this order.