| 摘要 |
PURPOSE:To obtain bias voltage having no dependence on the power supply voltage by selecting and switching plural circuits which produce the same bias voltage in response to the level of the power supply voltage. CONSTITUTION:The bias voltages of the same level are delivered from the 1st and 2nd bias circuits 50 and 60. A switching circuit 80 is driven in response to the detection output of a power supply voltage detecting circuit 70. Then the output voltage of the circuit 50 or 60 is supplied to a bias output terminal 90. Then both circuits 50 and 60 are combined to obtain the bias voltage which has no dependence on the power supply voltage and has a small range of limitation of the power supply voltage and the temperature change. |
