Switching power supply including a rectifier circuit having switching elements, and electric power converter

A switching power supply comprising:

• a bridge circuit that converts a DC voltage to a first AC voltage;
• a transformer that converts the first AC voltage to a second AC voltage, the transformer including a primary winding connected to the bridge circuit and a secondary winding electromagnetically coupled with the primary winding;
• a rectifier circuit that rectifies the second AC voltage to generate a rectified voltage, the rectifier circuit connected to the secondary winding;
• and
• a smoothing circuit that smoothes the rectified voltage, the smoothing circuit connected to the rectifier circuit, wherein:
• the rectifier circuit includes:
• a first secondary-side diode that is disposed in a first current path extending between one end of the secondary winding and a first terminal of the smoothing circuit, the first secondary-side diode allowing a first current to pass through the first secondary-side diode in a direction from the one end of the secondary winding to the first terminal of the smoothing circuit,
• a second secondary-side diode that is disposed in a second current path extending between the other end of the secondary winding and the first terminal of the smoothing circuit, the second secondary-side diode allowing a second current to pass through the second secondary-side diode in a direction from the other end of the secondary winding to the first terminal of the smoothing circuit,
• a third secondary-side diode that is disposed in a third current path extending between the one end of the secondary winding and the a second terminal of the smoothing circuit, third secondary-side diode allowing a third current to pass through the third secondary-side diode in a direction from the second terminal of the smoothing circuit to the one end of the secondary winding,
• a fourth secondary-side diode that is disposed in a fourth current path extending between the other end of the secondary winding and the second terminal of the smoothing circuit, the fourth secondary-side diode allowing a fourth current to pass through the fourth secondary-side diode in a direction from the second end of the smoothing circuit to the other end of the secondary winding,
• a first secondary-side switching element that switches a conduction of the first current flowing from the one end of the secondary winding to the first terminal of the smoothing circuit, the first secondary-side switching element disposed in the first current path in series with the first secondary-side diode,
• a second secondary-side switching element that switches a conduction of the second current flowing from the other end of the secondary winding to the first terminal of the smoothing circuit, the second secondary-side switching element disposed in the second current path in series with the second secondary-side diode, and
• a first node at which the first current path and the second current path are connected to each other, the first node being electrically coupled to the first terminal, and
• the first secondary-side switching element and the second secondary-side switching element are connected in common to the first node.