Patent ID: 8253809

Claim:
An analog-digital converter comprising: comparators disposed to correspond to analog signals which are converted into digital signals and configured to compare a voltage value of the analog signal, which is converted into the digital signal, with a voltage value of a predetermined reference signal; counters disposed to correspond to the comparators and configured to count a count value at the time point when the comparison process of the corresponding comparator is finished; a determiner configured to determine a time point when all the comparators finish their comparison processes; and a reference signal generator generating a down-count reference signal having as an initial voltage value a voltage value which is greater by a predetermined voltage than the voltage value of the analog signal having the maximum voltage value among the analog signals converted into the digital signals at a previous time or generating an up-count reference signal having as an initial voltage value a voltage value which is smaller by a predetermined voltage than that of the analog signal having the minimum voltage value among the analog signals converted into the digital signals at the previous time, wherein each comparator compares a voltage value of the analog signal, which is converted into the digital signal at a subsequent time, with the voltage value of the reference signal generated by the reference signal generator.