PoE Chips and Equipment Provide Latest Building Blocks for High-Power PoE

Feb 13, 2008 4:38 PM
by David Morrison, Editor-in-Chief, Power Electronics Technology

Although the high-power power-over-Ethernet (PoE) standard IEEE-802.3at may still be a year away from ratification, the development of high-power PSE controller ICs, midspans, and power supplies continues with new devices enabling delivery of 36 W or 72 W per port. Recently introduced products from Microsemi, Phihong USA, and SL Power Electronics illustrate the performance and features offered by the current PoE technology. These products include 8- and 12-port PSE power managers optimized for the IEEE-802.3at draft standard, a 36-W per port PoE midspan, and a family of single-port 32-W power injectors.

PSE Power Manager ICs
Microsemi has announced an IEEE-802.3at-ready power-over-Ethernet (PoE) integrated solution family, delivering up to 60 W power for devices ranging from video screen phones and WiMAX transmitters to pan-tilt-zoom cameras, thin-clients and laptop computers.

The product family includes the PD69012 12-port PSE high PoE manager IC and the PD69008 8-port PSE high PoE manager IC. Both feature external power FETs, enabling switch manufacturers to build switches that can drive 36 W for every two-pairs. These power managers interface to devices consuming up to 30 W, with ongoing currents of 720 mA, as required by IEEE802.3at-draft 1.0.

Applications requiring up to 60 W can use the same Microsemi integrated circuits in a 4-pair configuration. The ICs support Layer-2 Classification and 2-event classification, which reduces the software resources required to implement PoE switches and is essential for building IEEE-802.3at midspans.

“The PD69012 and PD69008 were built to support the higher currents required by PoE Plus, allowing not only peace-of-mind but full optimization for IEEE802.3at,” says Daniel Feldman, PoE product line manager at Microsemi.

Both the PD69012 and PD69008 include all of the features found in lower-power PSE power managers such as the PD64012G and PD64004A and in the pre-standard PD64012GH and PD64004AH. Such features include detection of pre-standard devices, dynamic power management and emergency power management. In addition, the new devices add support for power management based on Layer-2 classification.

With increases in the maximum theoretical power per port, advanced power management features become critical for the design of PoE switches. These features can save integrators an average of 50% of the cost of adding PoE to a switch, by allowing sharing of power supplies and the employment of smaller power supplies, according to Microsemi.

"The PD69012 allows the industry to build next generation IEEE802.3at or PoE Plus switches and midspans, enabling support for products that require more power, such as PTZ security cameras and 802.11n APs," said Val Oliva, director of product strategy at Foundry Networks.

The PD69012 and PD69008 can be configured on a port-by-port basis to work in IEEE-802.3at mode or 100% IEEE-802.3af-compliant mode. Both PoE managers can be used standalone or with the PD69000, which enhances the power management support and provides a backwards-compatible interface with the PD63000 and PDIC66000. This approach guarantees customers who have been shipping PowerDsine PoE solutions in switches since 2002 can make minimal software changes to adopt the latest PoE technology.

"The PD69012 and PD69008 are designed with the flexibility to allow for both 36-W and 72-W solutions, enabling our customers to have compliant and efficient products ready when the IEEE-802.3at standard is ratified in early 2009," says Steve Litchfield, executive vice president and president of Microsemi's Analog Mixed Signal Group.
The PD69012 and PD69008 are sampling now and will be in volume production in Q2 2008.

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