Planar inductor for very small DC-DC convertors

The authors describe the development of a planar inductor and its application to DC-DC converters. The planar inductor fabricated had a small size (11*11*0.8 mm), 33 mu H inductance, and a maximum quality factor of 14. The very small DC-DC converter, using the planar inductor as an energy storage element. had a 250 kHz switching frequency, a 5 V 2 W typical output, and a power/volume ratio of up to 1.7 W/cm/sup 3/.<
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