I. Introduction
IT IS WIDELY accepted that future voltage regulator modules (VRMs) must be located closer to the load so that voltage deviations due to interconnect impedance can be reduced. However, a major limit is the size of magnetic components required; increasing current levels and tighter regulation windows translate to inductor requirements of higher inductance and current, which make miniaturization more difficult. In an effort to reduce output capacitor size, interleaved phases result in a partly distributed magnetic solution, in which total output current is divided between a number of phases. However, it has been found that the overall size of magnetic components can be larger than that of a single buck inductor [1]. Coupled inductors provide smaller solutions [2], [3], but interconnection with the load is not so flexible, as high current interconnects are coupled together. The possibility of replacing a single lumped inductor with equivalent parallel (i.e., distributed) components was investigated in this work, for each inductor in a four-phase interleaved buck circuit. Both cases of noncoupled and coupled inductors are investigated. Results illustrate how, in addition to being more compatible with load interconnects in this application, distributed components offer improved power density by improving the utilization of winding and core regions. Methods for determining optimum levels of distribution are proposed. Comparison of Inductor Component Specifications
Single | Parallel | Coupled | Parallel-coupled coupled | |
---|---|---|---|---|
105 | 105× n | 98 | 98× n | |
30 | 30÷n | 30 | 30÷n | |
27 | 27÷n | 27 | 27÷n |