Patent ID: 8514121

Claim:
A comparison circuit comprising: a first comparator with a first offset voltage for receiving an input signal and performing a first comparison operation to the input signal to generate a first comparison signal and a first inverse comparison signal; a second comparator with a second offset voltage for receiving the input signal and performing a second comparison operation to the input signal to generate a second comparison signal and a second inverse comparison signal, wherein the first offset voltage is larger than the second offset voltage; and a first time-to-digital comparator for receiving the first comparison signal and the second inverse comparison signal and generating a first determination signal and a second determination signal according to the first comparison signal and the second inverse comparison signal, wherein the first determination signal and the second determination signal indicate whether a voltage of the input signal is larger than a first middle voltage, and wherein the first middle voltage is equal to a half of the sum of the first offset voltage and the second offset voltage.