A new coupled inductors design in 2-phase interleaving VRM

In order to adapt the power delivery requirements of modern microprocessors of high current, low voltage and faster transient response, interleaving VRM with coupled inductors should be used. At first, this paper presents a numerical analysis of benefits of 2-phase coupled inductors and gives out the region of coupling coefficient in which the transient response speed increases meanwhile the steady-state ripple current decreases, coupled inductors should be designed in this region. Secondly, this paper proposes a novel magnetic coupling structure of 2-phase coupled inductors and sets up its magnetic model to simplify the coupling structure and reduce the winding length. Its validity is verified with 3D FEA simulation.