Toward the Next Level of PCB Usage in Power Electronic Converters

A means for power electronics to exploit the level of 3-D packaging already being implemented in compact consumer products, such as digital cameras, is investigated in order to increase its power density. The increase in functionality and usage of printed circuit board (PCB) in power electronic converters is highlighted and improvements proposed to boost PCB usage to the next level. The material and manufacturing cost of an embedded planar transformer in a PCB-assembled power converter has been substantially reduced by introducing flexible-foil PCB to create the many windings without increasing the remaining number of (expensive) rigid PCB layers. Aspects such as the required folding pattern and its PCB material usage receive qualitative and quantitative attention. Furthermore, increasing of PCB functionality as regards integration of passives, geometrical packaging, and 3-D thermal management enhancement has been addressed. Not only is it shown that the integration of passives into a single, multifunctional PCB transformer structure is feasible but also that the same integral PCB can be used to geometrically package the remaining bulky, low-frequency, discrete components to create a power-dense converter and enhance the 3-D thermal management. A power density improvement of 66% (from 150 to 250 W/L) is achieved by the technology demonstrator.