Microfabricated Magnetics on Silicon for Point of Load High Frequency Dc-Dc Converter Applications

This paper presents the design, fabrication, and characterization on silicon integrated magnetics for high-frequency power applications. The presented device achieves superior characteristics in terms of energy density, electrical resistance, current capability, and inductance versus frequency stability. In order to demonstrate the effectiveness of use of the presented device for high-frequency power applications, it is tested with two different buck point of load (PoL) dc–dc converters, one of them is off-shelf chipset and the other is designed specifically for the microdevice. Experimental measurements show that the microdevices achieve a maximum inductance of about 50 nH, electrical resistance of 300 mΩ, rated current capabilities up to 1 A, and stable L versus f characteristics up to 100 MHz. Also, the PoL buck converters with the microdevices achieve a peak efficiency of up to 82% with a flat efficiency curve at switching frequencies up to 30 MHz while providing tight output voltage regulation (<0.2%) and low temperature rise (40 °C) at the rated current.