| 摘要 |
PURPOSE: To provide the feeding system for operational amplifier circuit with which an operational amplifier circuit can be normally operated within a possible range even when there is any abnormality in a power supply voltage or a GND level. CONSTITUTION: This system is provided with an operational amplifier circuit 1 to which a positive/negative power source±Vcc is supplied from a power source part, and a reference potential generating part 2 for generating a reference potential VR from the positive/negative power supply voltage±Vcc supplied to the operational amplifier circuit 2 and the reference potential VR of the reference potential generating part 2 is supplied to the input of the operational amplifier circuit 1. Besides, power is fed to the operational amplifier circuit 1 by the output of a power source switching part 3 for respectively outputting any power supply voltage at the maximum level between plural kinds of positive/negative power supply voltages±A and±B of the power source part 6. Further, the positive/negative power source±Vcc is supplied to the reference potential generating part 2 corresponding to the detection of abnormality due to a power source monitor part 4 for monitoring the positive/negative power supply voltage±Vcc to be supplied to the operational amplifier circuit 1 or the reference potential GND, and the input of the operational amplifier circuit 1 is switched to the reference potential VR outputted from the reference potential generating part 2 by switch circuit parts 51 and 52 .
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