High Speed Digital Isolation in PoE+: Design Talk, ECN June 2009
Design Talk, ECN June 2009
The new IEEE 802.3at standard is best known for its expansion of the powered device (PD) maximum power to 25.5 W from the 13 W “.af” level. Perhaps more significant, however, is the added control functions included in the standard that allows for dynamic allocation of power from the power sourcing equipment (PSE) to the network of powered devices. Dynamic and intelligent power allocation makes it possible to manage power over the network much in the same way as bandwidth is now managed. But to take full advantage of this new standard, it is necessary to acquire realtime power usage data from the primary side of each PD and transmit this information back to the PSE over the Ethernet data-link layer packets.
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