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Novel silicon-embedded magnetic devices for power electronic applications

Authors Wu, Rongxiang
Issue Date 2011
Summary Magnetic devices including inductors and transformers are key components in high performance power management systems. Current portable, high current and isolation applications require compact, high performance monolithic power electronic magnetic devices for overall system size, parasitics, and cost reductions. However, the previously available monolithic power electronic magnetic devices either consume large chip area or have poor performance. Therefore, in this thesis, novel compact, high performance silicon-embedded magnetic devices are proposed and demonstrated for various power electronic applications. First, a novel 0.8 mm2 silicon-embedded coreless power inductor (SECPI) is demonstrated for compact, high efficiency, and high current density monolithic dc-dc conversion. The fabricated SECPI shows similar or better inductor efficiency (93.4%) and much higher (2.5x~6x) current handling capability (optimal load current = 0.6A) compared to the prior arts. Second, it has also been experimentally demonstrated that by varying the number of turns, the SECPI is suitable for a wide range of load current levels with sufficiently high inductor efficiency, and when reducing the inductor size from 2 mm2 to 0.8 mm2, it has little impact on the SECPI performance. Third, magnetic coupling effect between the SECPI and other converter components has also been studied. The numerical simulation results suggest that magnetic coupling effect should be considered for designing high performance monolithic switched-mode converters. Fourth, 0.5 mm2 coupled SECPIs were designed and demonstrated for the monolithic dc-dc converter with the highest efficiency reported so far. The demonstrated coupled SECPIs allow the converter efficiency to be improved from 77.9% to 86.2%. Finally, a novel 2 mm2 silicon embedded coreless transformer (SECT) is demonstrated for compact, high performance monolithic isolated signal and power transfer. For isolated signal transfer, the demonstrated SECT shows the best voltage gain reported so far (-0.8 dB), and for isolated power transfer, the demonstrated SECT shows a potentially much better transformer efficiency (85%) and the best current and power handling capabilities (optimal load = 6 Ω) compared to the prior art.
Note Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2011
Language English
Format Thesis
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