| 摘要 |
PROBLEM TO BE SOLVED: To obtain a self-excited DC-DC converter circuit in which a switching frequency is prevented from becoming too high. SOLUTION: The DC-DC converter circuit for converting a DC input voltage Vin into a DC output voltage Vout comprises a current supply transistor Q51 provided between an input terminal applied with the input voltage Vin and an output terminal generating the output voltage Vout, and a control transistor Q52 for controlling the supply of a base current to the Q51 and repeating conduction and non-conduction depending on the voltage ripple of the output voltage. Even if the output voltage drops after the transistor Q51 is rendered nonconductive and the transistor Q52 is rendered conductive, an interrupting circuit 10 short-circuits a base and an emitter of the transistor Q51 to sustain the nonconductive state thereof for a specified time. The interrupting circuit 10 prevents the conduction of the transistor Q51 from starting earlier than a specified time thus preventing the switching frequency of the converter circuit from becoming too high. COPYRIGHT: (C)2004,JPO
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