A method includes generating a gain transition signal in response to any one of an average value of a feedback signal, a slope of the feedback signal, a slope of an input signal of the power converter, a maximum value of the input signal, and a minimum value of the input signal, and generating a first gain control signal and a second gain control signal in response to the gain transition signal. A gain transition controller includes a transition signal generator generating the gain transition signal and a gain control signal generator generating the first gain control signal and the second gain control signal in response to the gain transition signal.