IEEE 802.3at Voltage Limits · IEEE 802.3at Voltage Limits Keith Hopwood Phoenix Jan 2006
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Transcript of IEEE 802.3at Voltage Limits · IEEE 802.3at Voltage Limits Keith Hopwood Phoenix Jan 2006
![Page 1: IEEE 802.3at Voltage Limits · IEEE 802.3at Voltage Limits Keith Hopwood Phoenix Jan 2006](https://reader033.fdocuments.in/reader033/viewer/2022052420/5aeebe887f8b9a572b8d223f/html5/thumbnails/1.jpg)
IEEE 802.3atVoltage Limits
Keith HopwoodPhoenixJan 2006
![Page 2: IEEE 802.3at Voltage Limits · IEEE 802.3at Voltage Limits Keith Hopwood Phoenix Jan 2006](https://reader033.fdocuments.in/reader033/viewer/2022052420/5aeebe887f8b9a572b8d223f/html5/thumbnails/2.jpg)
IEEE802.3at Phoenix January 2006
Whats theoretical PD Power vsPSE Voltage due to drops in the cable?
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IEEE802.3at Phoenix January 2006
2 Pair Current vs Voltage
24.171.1423.470.9120.700.6815.870.4512.950.3544
25.311.1124.200.8921.110.6716.050.4413.060.3445
26.371.0924.880.8721.490.6516.220.4313.160.3346
27.371.0625.510.8521.850.6416.380.4313.250.3347
28.301.0426.110.8322.190.6316.530.4213.340.3248
30.001.0027.200.8022.800.6016.800.4013.500.3150
30.780.9827.700.7823.080.5916.920.3913.580.3051
31.510.9628.170.7723.340.5817.040.3813.650.3052
32.200.9428.610.7523.590.5717.150.3813.710.2953
32.850.9329.030.7423.830.5617.260.3713.770.2954
33.470.9129.420.7324.050.5517.360.3613.830.2855
34.060.8929.800.7124.260.5417.450.3613.890.2856
34.610.8830.150.7024.460.5317.540.3513.940.2757
PD Pwr50WPD Pwr40WPD Pwr30WPD Pwr20WPD Pwr15.4WOutput(V)
Current @
Current @
Current @
Current @
Current @PSE
![Page 4: IEEE 802.3at Voltage Limits · IEEE 802.3at Voltage Limits Keith Hopwood Phoenix Jan 2006](https://reader033.fdocuments.in/reader033/viewer/2022052420/5aeebe887f8b9a572b8d223f/html5/thumbnails/4.jpg)
IEEE802.3at Phoenix January 2006
PD Power Limit vs PSE Voltage 2pair @30W
20.00
21.00
22.00
23.00
24.00
25.00
44 45 46 47 48 49 50 51 52 53 54 55 56 57
PSE Voltage
PD P
ower
(W)
0.50
0.55
0.60
0.65
0.70
30W30W Current
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IEEE802.3at Phoenix January 2006
PD Power Limit vs PSE Voltage 2pair @50W
20.0022.0024.0026.0028.0030.0032.0034.0036.00
44 45 46 47 48 49 50 51 52 53 54 55 56 57
PSE Voltage
PD
Pow
er(W
)
0.800.850.900.951.001.051.101.151.20
50W50W Current
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IEEE802.3at Phoenix January 2006
4Pair Current vs Voltage
57.350.8050.700.6843.540.5735.870.4527.680.3444
57.900.7851.110.6743.830.5636.050.4427.780.3345
58.420.7651.490.6544.090.5436.220.4327.870.3346
58.910.7451.850.6444.340.5336.380.4327.960.3247
59.370.7352.190.6344.570.5236.530.4228.050.3148
60.200.7052.800.6045.000.5036.800.4028.200.3050
60.580.6953.080.5945.190.4936.920.3928.270.2951
60.940.6753.340.5845.380.4837.040.3828.340.2952
61.280.6653.590.5745.550.4737.150.3828.400.2853
61.600.6553.830.5645.710.4637.260.3728.460.2854
61.900.6454.050.5545.870.4537.360.3628.510.2755
62.190.6354.260.5446.010.4537.450.3628.570.2756
62.460.6154.460.5346.150.4437.540.3528.610.2657
PD Pwr70WPD Pwr60WPD Pwr50WPD Pwr40WPD Pwr30WOutput
Current @
Current @
Current @
Current @
Current @PSE
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IEEE802.3at Phoenix January 2006
PD Power Limit vs PSE Voltage 4 Pair@50W PSE o/p
43.0043.5044.0044.5045.0045.5046.0046.50
44 45 46 47 48 49 50 51 52 53 54 55 56 57
Voltage
PD P
ower
(W)
0.35
0.40
0.45
0.50
0.55
0.60
PD Power
Current
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IEEE802.3at Phoenix January 2006
PD Power Limit vs PSE Voltage4 Pair @60W PSE o/p
50.00
51.00
52.00
53.00
54.00
55.00
44 45 46 47 48 49 50 51 52 53 54 55 56 57
PSE Voltage
PD
Pow
er(W
)
0.350.400.450.500.550.600.650.70
PD PowerCurrent
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IEEE802.3at Phoenix January 2006
Conclusion
• Not much Power Increase per Volt above 51V– @ 0.5A less than 1W gained at PD per Volt
• PD Power above 51V @ 0.5A– 45W 4 Pair– 22.5W 2 Par
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IEEE802.3at Phoenix January 2006
Practical Voltage Range in PSE
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IEEE802.3at Phoenix January 2006
PSE Model
Data fromPHY
Data fromPHY
Control
Power +
Power RTN
RJ45
RJ45
Interconnect
Interconnect
Switch
Fuse Diode
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IEEE802.3at Phoenix January 2006
Power Source Voltage Tolerance
• Initial Set-point 0.1% to 5%• Load Regulation• Line Regulation• Temperature Drift 0.03%/deg C =~1%
Total error range could +/-2% to 8%@50V 2%=+/-1V 8%=+/-4V
Typical +/-1 to 2%
![Page 13: IEEE 802.3at Voltage Limits · IEEE 802.3at Voltage Limits Keith Hopwood Phoenix Jan 2006](https://reader033.fdocuments.in/reader033/viewer/2022052420/5aeebe887f8b9a572b8d223f/html5/thumbnails/13.jpg)
IEEE802.3at Phoenix January 2006
PSE Model
Data fromPHY
Data fromPHY
Control
Power +
Power RTN
RJ45
RJ45
Interconnect
Interconnect
Switch
Fuse Diode
![Page 14: IEEE 802.3at Voltage Limits · IEEE 802.3at Voltage Limits Keith Hopwood Phoenix Jan 2006](https://reader033.fdocuments.in/reader033/viewer/2022052420/5aeebe887f8b9a572b8d223f/html5/thumbnails/14.jpg)
IEEE802.3at Phoenix January 2006
PSE Loss Simple Model
Switch
CurrentSense
AC DisconnectOr protection
Connector
Transformer
DistributionPCBConnectorsFuse
Input Source
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IEEE802.3at Phoenix January 2006
PSE Losses
0.3ohmsMeasured0.05-0.150V@350mA
<0.5V0.05 – 1 ohm
.1 to 2 ohms
0.6V
0.105V0.05V0.5V0.017 -0.35V
@350mA0.035 –0.750V
0.6V
ConnectorTransformerDistributionSwitchCurrent Sense
AC Disconnect or Redundant Diode
![Page 16: IEEE 802.3at Voltage Limits · IEEE 802.3at Voltage Limits Keith Hopwood Phoenix Jan 2006](https://reader033.fdocuments.in/reader033/viewer/2022052420/5aeebe887f8b9a572b8d223f/html5/thumbnails/16.jpg)
IEEE802.3at Phoenix January 2006
PSE Loss @ 350mA
Realistic Design after the Power Supply.All Regulation (Drops)
Good Design 1.5VPoor DC Loss Design 3.5V
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IEEE802.3at Phoenix January 2006
Pragmatic Solution
PSU+/-2%
PSE 1.5V
48495051525354555657