Abstract: The invention provides a digital active EMI filter that removes, minimizes, or reduces unwanted interference (i.e., EMI noise) generated by a power circuit such as, for example, a power converter. Digital active filtering includes digital sampling of the incident noise signal amplitude and frequency, discrete time conversion of the EMI noise source, processing (e.g., inverting) the digital signal, and then constructing an analog output signal (i.e., an EMI compensation signal) which is injected to the input of the power circuit. A digital EMI filter as described herein may be used in both differential-mode and common-mode configurations, and overcomes limitations of passive and active analog EMI filters.

Abstract: The invention provides a digital active EMI filter that removes, minimizes, or reduces unwanted interference (i.e., EMI noise) generated by a power circuit such as, for example, a power converter. Digital active filtering includes digital sampling of the incident noise signal amplitude and frequency, discrete time conversion of the EMI noise source, processing (e.g., inverting) the digital signal, and then constructing an analog output signal (i.e., an EMI compensation signal) which is injected to the input of the power circuit. A digital EMI filter as described herein may be used in both differential-mode and common-mode configurations, and overcomes limitations of passive and active analog EMI filters.