| 摘要 |
PURPOSE:To miniaturize the chip area by extracting a voltage across a unit resistor of a 1st resistor array via 1st and 2nd buffer amplifiers, and connecting a 2nd resistor array between the output terminals to constitute the 2nd resistor array independently of the 1st resistor array in configuration. CONSTITUTION:A D/A converter 18 consists of the 1st resistor array 66 comprising unit resistors R aud the 2nd resistor array 67 including buffer amplifiers 1, 2 whose gain is the unity to extract the voltage across one unit resistor and formed by connecting 2N of unit resistors between the output terminals of the amplifiers in series. The 1st output 19 is outputted at a terminal of a capacitor 14 via a switch 12, the 2nd output 20 is outputted at the 2nd terminal 22 of a differential amplifier 16 and the output of the differential amplifier 16 is inputted to a sequential comparison register 17, an analog signal Vx is fed to one terminal of the capacitor 14 via an analog input terminal 10 and a switch 11 and the other terminal of the capacitor 14 is connected to the 1st terminal 21 of the differential amplifier 16.
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