Patent ID: 8125291
Filing Date: 2012-02-28
Classification: H03H

Abstract:
1. A circuit for separating common mode (CM) and differential mode (DM) components of conducted electromagnetic interference (EMI) noise, said circuit comprising a pair of input ports, a pair of coupled inductors forming a transformer each coupled inductor of said pair of coupled inductors having one terminal connected to a respective one of said input ports, said coupled inductors being coupled to subtractively superimpose currents therein whereby a second terminal of one of said pair of coupled inductors outputs a fraction of said differential mode noise, a pair of series-connected coupled inductors forming a transformer each inductor of said pair of series connected coupled inductors having one terminal connected to a respective one of said input ports, said series connected coupled inductors being coupled to additively superimpose currents therein whereby a fraction of common mode noise is output from a node serially connecting said pair of series connected coupled inductors, and impedance matching resistors connected such that said circuit for separating common mode and differential mode components of conducted EMI noise is symmetrical with respect to respective input ports of said pair of input ports.