Patent ID: 7030791

Claim:
An A/D conversion device comprising: an input line for receiving a conversion object voltage; a first level shift circuit that shifts the conversion object voltage applied to the input line to a first object voltage, which is on a low potential side by a first offset voltage; a second level shift circuit that shifts the conversion object voltage applied to the input line to a second object voltage, which is on a high potential side by a second offset voltage; a selection circuit that selects the first object voltage outputted from the first level shift circuit when the conversion object voltage is equal to or more than a predetermined threshold, and selects the second object voltage outputted from the second level shift circuit when the conversion object voltage is less than the predetermined threshold; an A/D converter that takes in the voltage selected by the selection circuit and A/D converts it in a predetermined voltage range; and correcting means for correcting an A/D converted value outputted from the A/D converter according to a selection state of the selection circuit.