A spread spectrum switching regulator generally includes an reactive
circuit portion coupled to the input terminal, a switching element
coupled to the reactive circuit portion, and a control circuit portion
coupled between the switching element and the output terminal. The
switching element has a drive signal characterized by a duty cycle, and
the reactive circuitry portion is configured to produce an output voltage
at the output terminal responsive to the duty cycle of the drive signal.
The control circuit portion is configured to spread the input power
across multiple frequencies by adjusting the drive signal of the
switching element, thereby reducing input current noise through spread
spectrum techniques. The drive signal is responsive to a pseudo-randomly
generated ramp signal.