Analysis of coupled microinductors for power-supplyon-chip applications

Coupled microinductors fabricated on silicon offer improved voltage regulator performance and reduced power loss compared to equivalent uncoupled microinductors. An analysis of coupled microinductors variables is presented which illustrates the optimum number of phases in terms of efficiency and impact on other circuit components. Models for eddy core loss which accounts for phase angle variation are included and are used to investigate a number of coupled inductor configurations designed for operation in a 9 W multiphase DC-DC converter. Their performance is analysed and models are validated.