An integrated circuit according to the present invention comprises a ring oscillator, a first phase control unit, and a second phase control unit. The ring oscillator comprises one or more delay cells having delay values and generates two or more periodic waves. The first phase control unit changes the delay values of one or more delay cells from a first delay value to a second delay value according to a first comparison signal which corresponds to a phase difference by comparing the phase of a first selection periodic wave with the phase of a reference wave. The second phase control unit returns the delay values of one or more delay cells from the second delay value to the first delay value according to a second comparison signal which corresponds to the phase difference by comparing the phase of a second selection periodic wave with the phase of the reference wave. The time of returning the delay values of one or more delay cells to the first delay value corresponds to an interval from the time of starting the activation section of the first comparison signal to the time of ending the activation section of the second comparison signal.
