Layout Considerations and Thermal Analysis of a 1.8 MHz Resonant VRM

Practical realization of modern high current and high switching frequency converters (with strong skin and proximity effects) requires a good control on layout-dependent parasitic components and on the power losses (thermal management), in order to meet the goal of high efficiency and reliability. In this paper, the physical realization of a VRM rated at 1.3 V - 50 A and switching at 1.8 MHz is analyzed in detail and discussed. Three prototypes, with same layout but different PCB structures and SR MOSFETs, have been tested. Moreover, an accurate thermal model was developed and experimentally validated in order to predict the maximum temperature of critical components.