| 摘要 |
PURPOSE: A sequential comparison type A/D converter for improving conversion accuracy and a microcomputer are provided to enhance conversion accuracy by using distribution values of plural capacitive elements. CONSTITUTION: A sequential comparison type A/D converter includes serial resistors(2) for generating reference values to convert analog values to digital values of m-bits and a comparator(12) for comparing sequentially the analog value and one of the reference values and outputting a digital value. The sequential comparison type A/D converter further includes a plurality of capacitive elements(8,10) for distributing one of the reference values according to a capacitance ratio and a controller for switching a value compared to the analog value by the comparator from the reference value to a distribution value of the capacitive elements when the comparator outputs an m-bit digital value. At this time, the analog value is converted to the digital value of (m+n) bits digital.
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