| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a switching power supply device that is reduced in the number of components and suppresses a shorting loss in switching elements, and also suppresses a surge voltage onto an output rectifier device. <P>SOLUTION: Magnetic coupling between primary-side windings 31A-31D and secondary-side windings 32A, 32B and magnetic coupling between the primary-side windings 31A-31D and third windings 33A, 33B are both more loose than that between the secondary-side windings 32A, 32B and the third windings 33A, 33B. A leakage inductance component (inductor Lre) caused by each magnetic coupling and capacitors C1-C4 form an LC resonant circuit. Thereby, a ZVS operation can be achieved without providing an inductor separately from a transformer 3. A surge voltage suppression circuit 2 is provided, and thereby the surge voltage onto rectifier diodes 4A, 4B can be suppressed by the clamping operation of diodes D5-D8 with respect to the voltage across the third winding 33. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
