An Integrated EMI Choke for Differential-Mode and Common-Mode Noise Suppression

TLDR

The paper introduces a novel integrated EMI choke that combines differential‑mode and common‑mode suppression. The design integrates a low‑permeability DM choke inside the CM choke’s open window, shares a single winding, and is validated by small‑signal measurements of symmetry. The integrated choke reduces inductor footprint while delivering high DM inductance, and large‑signal tests confirm strong attenuation and acceptable thermal behavior.

Abstract

This letter presents a novel integration approach for the electromagnetic interference choke. A low-permeability differential-mode (DM) choke is placed within the open window of the common-mode (CM) choke. Both chokes share the same winding structure. With the proposed approach, the footprint of inductors is greatly reduced, and high-DM inductance can be achieved. First, small-signal measurement is carried out to demonstrate the design concept and the symmetry of the proposed structure. Then large-signal experimental results verify the attenuation characteristics, as well as the thermal performance.