| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of components in a dropper type series regulator 21 that is composed of discrete components, which stabilizes an output voltage VOUT by controlling the gate of FETQ1, in which an output controller 25 is placed in series with an output line 23, corresponding to the output voltage VOUT detected by a voltage detector 24. SOLUTION: In a usual switching power supply apparatus, a photocoupler PC1, which is used for insulation between a primary side and a secondary side, is used in the dropper type series regulator 21 without the necessity for insulation for simplifying a circuit. Thereby, only this photocoupler PC1 is used in place of discrete components, such as a plurality of transistors or resistances, so that the number of components can be reduced. COPYRIGHT: (C)2004,JPO&NCIPI
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