Circuit and method for controlling switching regulator

A switching regulator configured to generate an output voltage based on an input voltage using at least one power switch and an inductor, the switching regulator comprising:

• a first control circuit configured to generate a first control signal for turning off the power switch, in dependence of a level of the inductor current through the inductor;
• a second control circuit configured to generate, based on a reference clock signal for setting a switching frequency of the switching regulator, a second control signal for turning on the power switch, in dependence of the level of the inductor current through the inductor;
• and
• a frequency locking circuit coupled to the second control circuit and configured to generate a periodic threshold signal based on the reference clock signal to control the generation of the second control signal, wherein the periodic threshold signal is synchronized with the reference clock signal, and each period of the periodic threshold signal comprises a target waveform having at least two distinct signal portions.