N. Sturcken, R. Davies, C. Cheng, W. E. Bailey and K. L. Shepard “Design of Coupled Power Inductors with Crossed Anisotropy Magnetic Core for Integrated Power Conversion” Proceedings to the Applied Power Electronics Conference (APEC), 2012.
Design and partial microfabrication of a coupled power inductor is presented for use in high power-density integrated voltage regulators (IVR). The proposed inductor uses many laminations of uniaxial, high-permeability magnetic material where the orientation of anisotropy between successive laminations is rotated to provide an effectively isotropic core. The high permeability core allows for an inductance density of 200nH/mm2, while coupling between phases prevents magnetic saturation and allows a current density as high as 11A/mm2 according to quasi-static finite-element-analysis (FEA) simulations. The coupling factor, inductance and resistance of the device are optimized for operation in a four-phase integrated buck converter switching at 100MHz.