An interleaved switched mode power supply and control method therefor are disclosed. The interleaved switched mode power supply includes a first switched mode power supply; a second switched mode power supply; and a controller. The controller controls the first and second switched mode power supplies so that the controller and the first and second switched mode power supplies form an interleaved switched mode power supply with power factor correction. The controller modulates a switching frequency of each of the first and second switched mode power supplies such that the switching frequency varies based upon ripple current cancellation between the ripple current of the first switched mode power supply and the ripple current of the second switched mode power supply.