Electric power source device equipped with transformer

An electric power source device comprising:

• a transformer comprising a primary coil and a secondary coil;
• primary side semiconductor components forming a primary side circuit connected to the primary coil of the transformer;
• secondary side semiconductor components forming a secondary side circuit connected to the secondary coil of the transformer;
• a choke coil forming a smoothing circuit capable of smoothing an output voltage;
• a plurality of circuit substrates on which a control circuit is formed, the control circuit controlling some components in the primary side circuit and some components in the secondary side circuit, or at least one selected from the primary side circuit and the secondary side circuit;
• and
• a base plate on which the transformer, the primary side semiconductor components, the secondary side semiconductor components and the choke coil are formed,
• wherein the plurality of the circuit substrates comprises a first circuit substrate and one or more second circuit substrates, the first circuit substrate is arranged to be parallel to the base plate, and the second circuit substrate is arranged to be parallel to a normal line of the first circuit substrate.