| 摘要 |
In an isolation type DC-DC converter for performing full-wave rectification in the secondary of a transformer, two switching sections 11 and 13 alternately switch ON and OFF, thereby reversing the current I3 flowing through a primary winding 3a of the transformer 3. A switching control circuit 7 outputs switching signals G1 and G3 to the switching sections 11 and 13, respectively, thereby controlling the switching of the switching sections. A load current sensing section 9 senses the amount of load current, then compares it with a predetermined threshold value. When the amount of load current sensed is smaller than the threshold value, a delay circuit 8 delays the switching signals G1 and G3 to the switching sections 11 and 13 for a predetermined delay time. The delay time is set to be substantially equal to ¼ of the resonance period determined by the self-inductance of the primary winding 3a of the transformer 3.
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