Suggested Remedy for comment #183, 184

IEEE802.3at Task ForceVport ad hocSuggested Remedy for comment #183, 184October 2007Yair DarshanMicrosemi CorporationSuggested Remedy for comment #183, 184, Yair Darshan, October 2007 Page 1www.microsemi.comBackground for comments 183 and 184 Based on Vport ad-hoc meeting on October 11,2007 the group agree on the following baseline concept to address those comments:– (1) PD Model is constant power model Iport=Ppd/Vport– (2) Iport_avg and Iport_peak are function of Vport at PD input/PSE output– (3) Ipeak/Iavg = Ki_CLASS determined by the specifications (design constrains).– (4) Specification shall support legacy PD peak current numbers as presented in table 33-12 item 4. As a result of the above baseline, the following text corrections are proposed to meet (1) to (4) objectives.Suggested Remedy for comment #183, 184, Yair Darshan, October 2007 Page 2www.microsemi.comEq-2 is just IEEE802.3 Draft D0.9 StatusInformative..It is better to allow higher Idc for Ki ⋅(Vpse−Ki ⋅Iport_avg⋅Rc)class class(Eq−2) Kp =class 1,2 and to use the same class(Vpse−Iport_avg⋅Rc)0.4/0.35 ratio for all classes(Eq−3) Iport_ peak = Ki ⋅Iport_avgclass2Vpse−(Vpse −4⋅Ppd _avg⋅Rc)(Eq−1) Iport_avg =2⋅RcShown in the specification or derived directly from itCalculated values based on PD constant power equationsSuggested Remedy for comment #183, 184, Yair Darshan, October 2007 Page 3www.microsemi.comKey inputs Ki_class=Ipeak ...