| 摘要 |
A band gap constant voltage circuit is provided to perform rapid starting when a source voltage is input, or to adjust the starting time by adjusting the size of a p-type transistor. A band gap constant voltage circuit includes constant voltage sources(P101~P103,ND11~ND13), first and second level shift circuits(P114,P115), differential amplifiers(P112,P113,NL11,NL12), an output voltage detecting unit, and a current source(P119). The constant voltage sources output a constant voltage to an output terminal. The first and second level shift circuits vary the voltage level of the output terminal. The differential amplifiers receive outputs of the first and second level shift circuits, and control the voltage of the output terminal. The output voltage detecting unit monitors the voltage of the output terminal. The current source controls a current based on the voltage of the output terminal. A current from the current source is supplied to a transistor included in the level shift circuits, when the voltage of the output terminal is lower than a predetermined level.
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