I. Introduction
While DC/DC converters are well known for their significant advance in their power density per square inch, and their low thermal dissipation, the thread of generating Electromagnetic Interference (EMI) noise from the high frequencies embedded in their fast switching di/dt and dv/dt has always been a concern. As the DC/DC converters follow the new trend of power generation, their switching frequencies have increased dramatically to reduce their dimensions. Most of these DC/DC converters are PCB mount type and are installed in close proximity to microprocessors to provide DC supply to motherboards. Thus, having a DC/DC converter that can coexist with microprocessors without disturbing their operation could be a challenging design. The process of having the DC/DC converter to comply with its own environment, in terms of EMI, is referred as electromagnetic compatibility (EMC). This becomes an integrated part of the design requirements that should be addressed at the early stage of the project. Further details on EMI generation in DC switching converters can be found in [1]. EMI noise can be radiated in free space or conducted through power leads. However in this paper, only conducted noise will be discussed. There are two different modes of conducted noise, common mode (CM) and differential mode (DM) conducted EMI. It is important to discern between CM and DM noises to design a suitable passive filter. The separation of these modes is demonstrated in [2], [3]. There are some modeling techniques that have been used to predict the conducted EMI noise in switching converters [4]–[7]. These techniques can significantly contribute to the passive EMI filter design and optimization.