| 摘要 |
PURPOSE:To obtain the stable and highly accurate output voltage by keeping the base voltage of a transistor at a level higher than the base-emitter voltage in case the output potential of on operational amplifier is lowered less than said base-emitter voltage. CONSTITUTION:A voltage holding circuit 100 consists of a level discriminating circuit 1 for gate voltage of an N channel MOSFETM1 constituting an output stage, a resistance R which sets the holding voltage and a switch 2 which turns on and off the holding voltage. This circuit 100 is added to a band gap voltage generating circuit. Then said holding voltage is impressed when the gate voltage of the FETM1 is kept at a low level and while the transistor of the band gap voltage generating circuit is inactive. Thus the transistor works assuredly with impression of the power supply voltage, and the output voltage VREF of the voltage generating circuit is not stabilized in a zero state. Thus a desired output voltage level can be obtained. |
