Root Cause Analysis and Defect Ground Effect of EMI Problem for Power Electronics

The DC-DC converter is a crucial component of electronic modules or systems, and thus making electromagnetic interference issue essential. Even though power IC manufacturer often provides useful PCB design guidelines, but power electronic engineer sometimes ignores the design rules because of his own application concerned or cost issue. This usually leads the converter to a poor EMI performance in the first time, thus requiring additional engineering resources, greater time to market, as well as higher EMI filter costs to comply with related EMI regulations. In this paper, we'll analyze the root cause of EMI problem on a DC-DC converter module built with single layer-double side PCB, and point out some factors of PCB ground design that will affect the EMI performance. Since there is no complete pair for power-ground plane, the plane resonance issue will not be discussed in this paper.