IEEE 802.3bt Update

The IEEE 802.3bt standard defining power levels of up to 90 W has proven to be significantly advantageousto key digital ceiling applications. The new standard increases the maximum PoE power available, primarily by utilizing all four pairs of the structured wiring, thus solving the challenge of higher power and more efficient PoE delivery systems. In particular, the ‘automatic class’ functionality of the standard allows the power sourcing equipment (PSE) to determine the actual maximum power drawn by the connected powered device (PD). This unique power management feature of the IEEE 802.3bt standard turns out to be extremely beneficial to digital ceiling applications, as it enables a PSE to allocate leftover power to additional light bulbs if it knows that a specific LED luminaire will draw less than its class power; this optimizes power consumption, translating into significant cost benefits. The IEEE 802.3bt whitepaper provides more insights into the next-gen PoE standard.

The IEEE 802.3bt team is in the sponsor ballot phase. In the update done for D3.3 in comparison with D3.2, we added a clear requirement at the PSE that all the current measurement should be done on the negative pairs, where the PSE control circuitry is located, to ensure interoperability. In addition, in the dual-signature PD specification, we added a requirement that the current generated by the detection, connection check, and classification for each pair set will be independent from the other pair set on the negative pairs to ensure correct current measurement at the PD negative pairs when connected to the PSE.

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