Abstract: A power supply apparatus is described that includes a first switch, a second switch, a first comparator, a signal generator and a controller. The first switch is provided between an inductor and a terminal having a reference voltage. The second switch is provided between the inductor and an output terminal. The first comparator compares an input voltage and a first comparison voltage. The signal generator outputs a frequency signal based on an output of the first comparator. The first controller controls current flowing into the inductor by controlling the first switch and the second switch based on the output of the signal generator.