A power supply controller is provided. The power supply controller includes a switching device, an inductor, a comparator, and a sensing device. The switching device is coupled to an input power source and switches according to a comparing result. The inductor is coupled between the switching device and an output terminal, and conducts an inductor current. The comparator is coupled to the output terminal, a reference power source and a bias voltage, compares the voltage level of the output voltage and the reference voltage, and outputs the comparing result according to the bias voltage. The sensing device is coupled to the inductor and the comparator, senses the inductor current, generates a sensed voltage according to the inductor current, and adjusts the bias voltage according to the sensed voltage.