| 摘要 |
PROBLEM TO BE SOLVED: To determine the level of an input voltage without being affected by an offset voltage, an offset current, a bias current and their drifts present at an input part of a voltage comparison portion even in such a case. SOLUTION: A divided input voltage (V1) generated by dividing an input voltage (Vin) and a divided reference voltage (V2) generated by dividing a reference voltage (Vs) are inputted to a multiplexer (7). An A-D converter (8) is provided on the output side of the multiplexer and its output is inputted to an arithmetic circuit (9). The arithmetic circuit (9) outputs an input select signal (SEL) to the multiplexer which is made to switch the input, thereby receiving values obtained by A-D-converting the divided input voltage and the divided reference voltage from the A-D converter. The magnitude relation between the two received voltages is decided by digital operation to outputs the magnitude relation between the input voltage and an input conversion threshold voltage. COPYRIGHT: (C)2006,JPO&NCIPI
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