| 摘要 |
PURPOSE: To prevent an output voltage from being upstable by connecting the output of a differential amplifier to the input of a first follower stage by a controlled switching device, and closing the switching device when a power supply voltage reaches a certain threshold value. CONSTITUTION: The output of a differential amplifier Am is connected to the input of a first follower stage T by a controlled switching device 1, the input of the first follower stage T is connected to a first power supply terminal Vcc by a resistor R2 , and the output of the first follower stage T is connected with a power supply terminal B of a voltage generator REF. Then, this circuit is provided with a control circuit Co which controls the switching device 1 operated in order to receive at least the voltage supply voltage Vcc in a configuration that the switching device 1 is closed when the power supply voltage Vcc reaches a threshold value enabling the existence of the voltage generator REF and the differential amplifier Am in a so called operating zone. Thus, only when the power supply voltage Vcc is enough, the voltage of the voltage generator REF is transmitted to the input of the first follower stage T.
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