Abstract: An A/D conversion apparatus according to the present invention for comparing a reference signal with an analog signal, and when the reference signal matches with the analog signal, outputting a corresponding digital value, is provided, and the A/D conversion apparatus includes a gray code counter for generating the digital value from a reference clock or a reverse clock of the reference clock, and uses a gray code, in which a most significant bit to a second least significant bit of the digital value is a count value of the gray code counter and a least significant bit of the digital value is generated from the reference clock or the reverse clock thereof and defined as a least significant bit of the gray code counter.

Abstract: An A/D conversion apparatus according to the present invention for comparing a reference signal with an analog signal, and when the reference signal matches with the analog signal, outputting a corresponding digital value, is provided, and the A/D conversion apparatus includes a gray code counter for generating the digital value from a reference clock or a reverse clock of the reference clock, and uses a gray code, in which a most significant bit to a second least significant bit of the digital value is a count value of the gray code counter and a least significant bit of the digital value is generated from the reference clock or the reverse clock thereof and defined as a least significant bit of the gray code counter.