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| Improving Light Load Efficiency of High Frequency DC-DC Converters With Planar Nonlinear Inductors |
| Wang Laili, Pei Yunqing, Qin Yang, Yang Xu, Wang Zhaoan |
| Xi’an Jiaotong University Xi’an 710049 China |
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Abstract Light load efficiency of high frequency DC-DC converters used in portable electronic devices is very important for extending lifetime of batteries. This paper proposes to use large-range gradually changed nonlinear inductors with adaptive on time control to improve the light load efficiency not only in disconfinuous conduction mode(DCM), but also in continuous conduction mode(CCM). Loss reduction is demonstrated by calculating loss of a conventional converter and a converter implemented with the proposed method. Multi-permeability magnetic cores based on LTCC technology are advanced to realize the nonlinear inductors. An analytic model is set up to show the design of inductor. A two permeability inductor prototype is fabricated and evaluated. Its inductance is 180nH at full load, 1.02µH at no load.
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Received: 03 November 2010
Published: 19 March 2014
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2012, Vol. 27 
