DC bias current enhancement of multilayer chip inductors by using a nonmagnetic air gap

Abstract

To enhance the DC characteristics of multilayer chip (MLC) inductors, we optimized the effective permeability of the magnetic core material. However, the effective permeability value is not easily tuned by optimizing the magnetic materials. The effective permeability of the core material in a MLC inductor can be controlled by inserting a nonmagnetic air gap between the coil layers without changing the magnetic core material. A typical MLC inductor with a 10-turn planar coil with dimensions of 2.0 mm × 1.2 mm × 1.0 mm (w × l × t) including an air gap layer which placed at the center of planar coil was designed and simulated for various thicknesses. The DC characteristics (IDC at ΔL 30%) were enhanced from 300 mA to 700 mA with the insertion of an air gap and with increasing air-gap thickness.