| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC-DC converter which can be adapted to even a resonance-type DC-DC converter while preventing an erroneous operation at the secondary side of a transformer. SOLUTION: The DC-DC converter is constituted in such a manner that an input voltage V<SB>IN</SB>is periodically chopper-controlled by a main switch 15, a secondary current I<SB>2a</SB>which accordingly flows to the secondary winding 14B side of the transformer 14 is rectified by FETs 1B, 1C, a rectified secondary current I<SB>2b</SB>is smoothed by a smoothing circuit 18, and an output DC voltage Vo is outputted. The DC-DC converter also comprises: logic elements 10a, 10b into which AC components V<SB>1i</SB>, V<SB>2i</SB>of divided voltages obtained by dividing secondary voltages outputted to the secondary winding are inputted, and which operate thresholds with respect to the AC components V<SB>1i</SB>, V<SB>2i</SB>, and output pulse rows V<SB>1o</SB>, V<SB>2o</SB>according to the operation results to gates of the FETs 1B, 1C; and a logic element control means 20 which stops outputs of the logic elements 10a, 10b when the output DC voltage V<SB>O</SB>is not higher than a prescribed value. COPYRIGHT: (C)2008,JPO&INPIT
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