This reference design integrates a high power standard PoE-PD interface, able to support applications up to 100 W. The PoE-PD interface is based on the PM8805 system in package featuring two embedded active bridges with driving circuitry, a charge pump to drive the high side MOSFETs, a hot swap MOSFET and a standard single-signature interface, including detection, classification, UVLO and inrush current limitation.
The device signals successful PSE type identification to the system: it identifies a 4-pair PSE by monitoring the Ethernet cable pairs and providing the system with a dedicated matrix of Tx signals.
The PM8805 is suitable for building the interface for PoE switch mode power supplies for maximum conversion efficiency, with a PGD signal that can be used to enable downstream DC-DC converters or LED drivers with suitable electrical parameters.