In one embodiment, a control circuit may be configured to form a switching signal to switch a power transistor at a frequency to regulate an output voltage of the power supply to a target value wherein the control circuit is configured to operate in a normal operating mode and a start-up mode and wherein the control circuit is configured to switch the switching signal at a target frequency in response to operating in the normal operating mode. A first circuit may be configured to control the frequency of the switching signal to increase from a first frequency to a second frequency that is less than the target frequency in response to operating in the start-up mode.