ECE: Electrical & Computer Engineering
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Miniature dc-dc converter shrinks 51%

Qiang Li (Photograph by Dave Franusich)

Graduate student Qiang Li with a miniature dc-dc converter

Qiang Li, a CPES Ph.D. student, is working on creating miniature, higher-current dc-dc converters that are suitable for applications such as laptops. Today’s dc converters offer a choice of only one out of two options: high power density (W/in3) or high current (20A or higher).

To create a small converter able to handle high currents, Li is adapting the 3-D integration technology currently used in low power converters and the converter is integrated onto a single chip, saving space and increasing power density.

The new converter is embedded as a bare die on ceramic using a “stacked power” packaging technology that offers six-times greater thermal conductivity than a traditional printed circuit board. The improved thermal performance of the ceramic leads to an even distribution of temperature, preventing hotspots.

The converter pictured here represents a 51 percent reduction in size from the first prototype developed at CPES in 2006 and a seven-times improvement over industry state-of-the-art. The two-phase, four MOSFET converter produces converts 40A from 5V to 1.2V, coupling together the 20A capacity of each phase. Even at this higher current, the power density is about 500 W/in3.