| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of noise sound resulting from frequent variation in the switching frequency of a switching semiconductor element with a control terminal on the primary of a flyback transformer, in a power supply unit of pseudo-resonance system. SOLUTION: A skip variation suppression means 11 suppresses variations in the determination number of times of bottom skip for variations in PDP 12 as a load so that the number of times of bottom skip of voltage Vds does not change frequently, when an FET 6 on the primary of a flyback transformer 5 is inverted from off to on, even if the PDP 12 varies frequently, thus preventing variations in the switching frequency and preventing generation of noise sound resulting from frequent variations in the switching frequency. COPYRIGHT: (C)2009,JPO&INPIT
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