| 摘要 |
PURPOSE:To reduce an occupied area of a constant-voltage circuit and to raise yield, by connecting a resistance and a diode in order to compensate a variation for output voltage due to a variation of power supply voltage, in a constant- voltage circuit which utilizes a semiconductor element. CONSTITUTION:In case when the emitter of a transistor (TR) Q2 is an output VOUT and impedance of a load L is changed, and the output is varied, its variation is split by a resistance R1 and R2, is transmitted to the base of a TRQ1, the base current is varied, and the collector current is varied by hFE times of a varied portion of the base current. Subsequently, this collector potential is varied in the opposite direction to a variation of the base potential, it is applied to the TRQ2, and the potential difference of the output is kept constant. When the power supply voltage is large and is varied, the current of the TRQ1 becomes large, and when VBE becomes large, a current of a resistance R4 and a diode D1 increases, a current flowing to the resistance R2 decreases, and the power supply voltage of the output is compensated. A resistance value of the resistance R4 can be reduced by a forward direction voltage portion of the diode D1, and the chip size of an integrated circuit can be made small. |
