Conducted emission analysis and suppression of an immediate bus converter including load's RF impedance effect

A CE test layout with LISN at output side is proposed for a telecommunication immediate bus converter, which includes load's RF input impedance influences. Both the CM and DM paths of the interleaved Boost converter are analyzed in detail. The CM role of the output voltage ripple noise of the converter is explained and a non-intrinsic CM phenomenon caused by original DM sources is discovered too. Circuit simulation and experiment results verified the above analysis. In the end, some EMI filter design processes are proposed and tested to suppress the conducted EMI.