ANALOG AND DIGITAL CONVERTING DEVICE

摘要

PURPOSE:To shorten an A/D conversion time when a sensor output varies slowly by comparing an A/D-converted value with the last digital data stored value and varying the data toward the value of the sensor output. CONSTITUTION:A sensor signal voltage 10 detected by a thermistor sensor 2 is compared by a comparator 5 with the value 11 obtained by D/A-converting the last digital data stored value by a D/A-converter 4 and the comparison result is inputted to a microcomputer 1. The microcomputer 1 increases or decreases the D/A-converted reference signal voltage 11 stepwise according to the comparison result, and the increase or decrease and comparison are repeated until the comparison value is inverted. Then, digital data corresponding to the final output reference voltage 11 is regarded as input data.