SWITCHING POWER-SUPPLY DEVICE AND POWER CONVERSION DEVICE

摘要

PROBLEM TO BE SOLVED: To improve the efficiency and characteristics of a switching power-supply device of a secondary-side phase shift system.SOLUTION: A bridge circuit converts a DC voltage into an AC voltage. A transformer includes a primary winding N1 connected to the bridge circuit and a secondary winding N2 electromagnetically coupled to the first winding N1. A rectifier circuit rectifies an AC voltage inputted from the secondary winding N2. A smoothing circuit smooths the voltage rectified by the rectifier circuit. The rectifier circuit includes a secondary-side switching element inserted into a current path. The on-period of the secondary-side switching element is set to be longer than the on-period of a primary-side switching element included in the bridge circuit.