Core Materials for High Frequency VRM Inductors

The application of PCB integrated electroplated cores for VRM inductors is proposed, where the motivation is to increase frequencies beyond 1 MHz so that VRM transient response can be improved. It is shown that electroplated alloys have loss properties that are at least competitive with those of the highest frequency ferrite material available. Various PCB integrated inductor designs are presented, with toroidal cores providing the smallest solution. Measured losses under non-sinusoidal operating conditions are provided and work is ongoing to characterise the materials further.