Design Considerations for Passive Substrate with Ferrite Materials Embedded in Printed Circuit Board (PCB)

For higher power density of power electronics converters, the integration of passive into the printed circuit board (PCB) is a low cost and integral manufacturing approach. The passive substrate concept for power electronics is proposed in this paper. Based on it, the converter level packaging can be implemented. The commercially available ferrite materials with low high frequency loss can be embedded in the PCB. The configuration and manufacturing processes of the passive substrate are described. As an example, a 3.3V/20A output non-isolated synchronous buck DC-DC converter with 500 kHz switching frequency is designed and manufactured using the passive substrate that functions as the inductor. The electrical design and power loss analysis of the passive substrate are illustrated. The thin converter, better thermal performance and high power density can be achieved.