| 摘要 |
PURPOSE: To make it possible to cancel the offset voltage of an amplifier circuit by applying potential corresponding to a potential difference applied between plural intermediate terminals or an equal potential level applied to the intermediate terminals to an output terminal. CONSTITUTION: When a node N2 is set up to an L level in an input potential difference measuring mode, switches S1, S4 are turned off, switches S2, S3 are turned on and the fine output potential differenceΔV of a voltage sensor is inputted between nodes N1, N3. When the node N2 is turned to an H level in an offset voltage measuring mode, the switches S1, S4 are turned on, the switches S2, S3 are turned off and an equal potential level is inputted to both the nodes N1, N3. When the potential VN13 of a node N13 is adjusted by switching the potential VN13 between the input potential difference measuring mode and an offset voltage measuring mode, a potential difference applied to a node N11 can be set up to a fixed value in each of both modes.
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