Patent ID: 9722491
Date: 2017-08-01
CPC Classifications: H02M

Claim:
1. An apparatus comprising: a pulse width modulation controller configured to produce a first pulse width modulation signal at a first frequency; a switchmode power supply switching element including a control terminal; and a harmonic filter coupled between the pulse width modulation controller and the control terminal of the switching element, the harmonic filter configured to provide a second pulse width modulation signal at a second frequency to the control terminal of the switching element, where the second frequency is higher than the first frequency wherein the second frequency is at least one harmonic frequency of the first frequency equal to or greater than a second order harmonic of the first frequency and wherein a fundamental first-order harmonic component of the first frequency in the first pulse width modulation signal is filtered out or attenuated by the harmonic filter to provide the second pulse width modulation signal.