A control circuit for controlling a switching transistor of a switching regulator includes a hysteresis comparator circuit comparing a feedback voltage according to an output signal of the switching regulator with a reference voltage and a threshold voltage and outputting a pulse width modulation signal as an output signal of the hysteresis comparator circuit, where the threshold voltage has a hysteresis according to the pulse width modulation signal. The control circuit further includes a driver driving the switching transistor based on the pulse width modulation signal, a phase comparator generating a phase difference signal based on a phase difference between a reference clock signal and a pulse signal corresponding to the pulse width modulation signal, and a loop filter generating a control voltage by filtering the phase difference signal. The hysteresis comparator circuit is further configured to control a response speed thereof depending on the control voltage.