Patent ID: 8174427
Filing Date: 2012-05-08
Classification: H03M,H04N

Abstract:
1. An analog to digital (A/D) converter comprising: a determination circuit configured to determine whether a first analog signal is greater than a second analog signal or not, the first analog signal being a present A/D conversion target, the second analog signal being an immediately preceding A/D conversion target; a calculation circuit configured to add a reference voltage to a difference obtained by subtracting the second analog signal from the first analog signal; a generation circuit configured to generate a comparison voltage rising from the reference voltage as an initial value if the first analog signal is greater than the second analog signal, and to generate a comparison voltage falling from the reference voltage as the initial value if the first analog signal is smaller than the second analog signal; a comparator configured to compare a calculated value of the calculation circuit with the comparison voltage; and a conversion circuit configured to convert a period into a digital signal, the period being required until the calculated value is identical with the comparison voltage by the comparator.