| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage conversion circuit in which both response and low loss are satisfied, and to provide a switching power supply. SOLUTION: The voltage conversion circuit comprises a main voltage conversion circuit (circuit block 12) for converting an AC voltage into a DC voltage, an auxiliary voltage converting section (D1 and C1) for converting the AC voltage during transient period into a DC voltage to be output, a voltage limit section (constant voltage diode D2) for limiting the DC voltage output from the auxiliary voltage converting section, and an output control switch (transistor Q1) connected with the passage between the auxiliary voltage converting section and an output node 108 and conducting or nonconducting the passage so that a higher voltage can be outputted based on the relation of magnitude between the voltage at the output node 108 and a limit voltage. COPYRIGHT: (C)2007,JPO&INPIT
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