Adjustable High Current Low Profile Sandwich Inductor Using Nanocrystalline Flake Ribbon Core

Abstract

Compact and high current inductors determine the power density and efficiency of voltage regulators (VRs) for computing ICs. Conventional moulding structures using powder cores and gapped ferrite cores are reaching the limits of size miniaturization. In this paper, a sandwich-structured inductor using 2D magnetic nanocrystalline flake ribbon (NFR) is developed to achieve high current density and low height. The analytical models of inductance and conduction losses are developed and validated by finite element methods and experiments. A 5 to 1 V, 50 A, VR is built to compare the performance of the fabricated NFR sandwich inductor to the latest commercial counterpart. Thermal performance is investigated, stability tests under solder iron heat and reflow temperature are performed. The fabricated sandwich inductor is featured as simple structure, low profile, low DC resistance (DCR), high saturation current, soldering heat stable, but in the modest compromise of the AC conduction and core losses.

Keywords

• High current
• high frequency magnetics
• nanocrystalline
• planar inductor
• voltage regulator (VR)