| 摘要 |
PROBLEM TO BE SOLVED: To improve output voltage accuracy, in a constant-voltage circuit outputting a constant voltage from an output terminal. SOLUTION: A voltage detection circuit 8 detects a base-emitter voltage VBE (Q1) of a transistor Q1, and a current output circuit 9 outputs a bias current I1, according to the detected voltage. When the voltage VBE (Q1) is increased, the output current I1 of the current output circuit 9 is increased, and a base/emitter voltage VBE (Q2) of a transistor Q2 is also increased. Contrarily, when the voltage VBE (Q1) is reduced, the output current I1 of the current output circuit 9 is reduced, and the base/emitter voltage VBE (Q2) of the transistor Q2 is also reduced. As a result, the base/emitter voltages VBE of the transistor Q1 and the transistor Q2 are equalized, regardless of a load change to bring an output voltage VOUT into line with a Zener voltage Vz with high accuracy. COPYRIGHT: (C)2005,JPO&NCIPI
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