Summary of Contents for PowerDsine IEEE802.3
- Page 1 IEEE802.3at Task Force Technical and market considerations regarding PoEp output voltage range Vancouver BC, November 2005 Arkadiy Peker Daniel Feldman Yair Darshan www.powerdsine.com...
- Page 2 Part A Technical Considerations regarding PoEp output voltage range www.powerdsine.com...
- Page 3 Objectives To discuss optimum voltage range for PoEp To show advantages of having PoEp minimum voltage of 51V www.PowerDsine.com PowerDsine Presentation October 2005 Page 3...
- Page 4 Increasing Power delivery to the load for a given current value. Hence same infrastructure delivers more power to PDs for given PSE PS size and cost Bottom line: more applications may supported – Larger POEp market www.PowerDsine.com PowerDsine Presentation October 2005 Page 4...
- Page 5 It means, that at 51V, for the same power dissipation on the cable, power delivered to the load will be 4.9W more then at 44V. The advantage of higher voltage is further increased for higher currents than 0.35A www.PowerDsine.com 3.06W 3.06W 27.74W 32.64W PowerDsine Presentation October 2005 Page 5...
- Page 6 Advantages of higher voltage is increase with increasing power level Pd power Current per pair Power dissipation on a cables (4P) PSE power System efficiency for ~500W PSE PS www.PowerDsine.com 0.54A 7.3W 47.52W 0.84 PowerDsine Presentation 0.44A 4.85W 44.88W 0.89 October 2005 Page 6...
- Page 7 PoEp minimum voltage 51V required smaller PSE power supply then at 44V, for the same load. The technical advantage is clear for using higher voltage minimum voltage level for POEp PSE. Let consider different options in PoEp Power architectures :...
- Page 8 PoEp Power Architecture-AC Input www.PowerDsine.com PowerDsine Presentation October 2005 Page 8...
- Page 9 PoEp Power Architecture-AC Input One of the arguments for not using 51V power supply is that back up battery operates up to ~ 43 - 44V. However most batteries used in telecommunication have one of the terminal grounded (mostly positive)
- Page 10 It means battery life would not be fully utilize Adding boost converter, which would keep output voltage of the system constant, in our case 51V,would extend batteries capabilities on ~15% in POE systems www.PowerDsine.com PowerDsine Presentation October 2005 Page 10...
- Page 11 PoEp Power Architecture-AC UPS www.PowerDsine.com PowerDsine Presentation October 2005 Page 11...
- Page 12 But under the same conditions, 51V output power supply will have higher efficiency then 44V PS Estimated cost of additional boost circuitry for supporting the change from 45V to 52V for 500W power supply is about 10% cost of power supply. www.PowerDsine.com...
- Page 13 PoEp with Boost circuit POE PS Battery www.PowerDsine.com PowerDsine Presentation October 2005 Page 13...
- Page 14 AC or Battery Circuit POE PS •For 48V 250W power supply, maximum power for add power converter would be (52V-48V)*(500/48)=42W or about 9% of 500W PS cost •However taken in account improved system efficiency, total cost of ownership would remain about the same www.PowerDsine.com...
- Page 15 51V in PoEp PSE Regardless of output voltage consideration, adding boost circuit for system with batteries back up, would increase battery useful life in POE systems www.PowerDsine.com PowerDsine Presentation October 2005 Page 15...
- Page 16 Part B Market considerations regarding 802.3at output voltage range www.powerdsine.com...
- Page 17 802.3af modular installed base considerations 802.3af minimum PSE voltage: 44V Modular switches – 44V power supply is deployed with chassis – Customer expectation: 802.3at-blades added to 802.3af-chassis – 51V minimum at PSE More power dissipation at blade More components added to crowded blade www.PowerDsine.com...
- Page 18 The Conflict is: – 51V is the Technically preferred solution More power at low cost Bigger addressable market – 44V addresses the existing modular installed base Impossible to replaced 44V power supplies on the field www.PowerDsine.com PowerDsine Presentation October 2005 Page 18...
- Page 19 Part a: power classes that can work with either 44V or 51V. Part b: power classes that can work only with 51V minimum at the PSE. – This may be documented in the Informative section of the standard. www.PowerDsine.com PowerDsine Presentation October 2005 Page 19...
- Page 20 (In order to PSE to know if to power or not) To differentiate between 802.3af PD and PoEp PD. – 802.3at PSE extended classification is optional. Like classification is currently optional in 802.3af www.PowerDsine.com PowerDsine Presentation October 2005 Page 20...
- Page 21 It is perfectly OK that Switch/PSE is 802.3at compliant as long as its Power Supply supports 51V. If PSE PS Power Supply is 44V, then 802.3at PSE is not compliant but working and covered most of high power classes www.PowerDsine.com...
- Page 22 Discussion www.PowerDsine.com PowerDsine Presentation October 2005 Page 22...
- Page 23 References An Extended Classification Proposal-Proposal #1. Yair Darshan, Vancouver BC, November 2005 www.PowerDsine.com PowerDsine Presentation October 2005 Page 23...
- Page 24 Annex A: Enhanced Classification table Example for group A and group B With Pmax=40W Group B www.PowerDsine.com PowerDsine Presentation October 2005 Page 24...
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