A method for a switched mode power supply (SMPS) includes providing an error voltage signal based on a difference between a sampled output voltage of the SMPS and a target voltage, and generating a clock signal characterized by an oscillating frequency; generating a switching control signal based on the error voltage signal and the clock signal using pulse-width modulation (PWM). The method further includes varying the oscillating frequency of the clock signal according to the error voltage signal in a current generating circuit, and applying the switching control signal to control the power switches of the SMPS.