A controller for, related method of controlling a switch of, a power converter, and a power converter employing same. The controller is employable with a power train of a power converter including a switch configured to conduct for a duty cycle and provide a regulated output characteristic at an output thereof. In one embodiment, the controller includes an oscillator configured to provide a clock signal having multiple phases. The controller also includes a modulator configured to select a phase of the clock signal as a function of a portion of a digital duty cycle signal to refine a resolution of the duty cycle and provide a signal to control the duty cycle of the switch as a function of the digital duty cycle signal.