System and method for policing bad powered devices in power over ethernet
A system and method for policing bad powered devices in power over Ethernet. Degradation of components within powered devices can lead to noise and ripple that exceed specified thresholds. This noise and ripple can adversely impact the operation of the power sourcing equipment. A noise detector implemented in the power sourcing equipment can detect the presence of such noise and ripple and modify the application of power to the particular port.
1. A remote powering method in a power sourcing equipment, comprising:
detecting a presence of a valid powered device that is capable of receiving power via a port, said powered device being coupled to said port via a cable;
after completion of said detection of said power device applying power to said port at a first power level for powered operation of said powered device;
determining, during said application of said power at said first power level whether a noise ripple level represented by a periodic variation of a voltage level on said cable exceeds a threshold level; and
modifying an application of power to said port to a second power level if said determination indicates that said noise ripple level on said cable exceeds said threshold level.
2. The method of claim 1 , wherein said determining comprises determining a noise ripple level in a frequency range.
3. The method of claim 2 , wherein said determining comprises determining with a band-pass filter.
4. The method of claim 2 , wherein said determining comprises determining a noise ripple level in a frequency range based on harmonics and/or sub-harmonics of a frequency of operation of a power converter in said powered device.
5. The method of claim 2 , wherein said determining comprises determining whether a current ripple level exceeds said threshold level.
6. The method of claim 2 , wherein said determining comprises determining whether a voltage ripple level exceeds said threshold level.
7. The method of claim 6 , wherein said determining comprises determining whether a voltage ripple level exceeds a threshold level defined by IEEE 802.3af.
8. The method of claim 1 , wherein said modifying comprises modifying an application of power to said port to a zero power level.
9. The method of claim 1 , wherein said determining comprises determining whether a noise ripple level on said cable exceeds a threshold level defined by a profile.
10. A power sourcing equipment system, comprising:
a power supply for delivering power to a port coupled to a valid powered device via a cable, wherein a validity of said powered device is determined using a detection process;
a detector that determines, during a delivery of power by said power supply to said port, whether a noise ripple level represented by a periodic variation of a voltage level on said cable exceeds a threshold level; and
a controller that modifies said delivery of power to said port based on said determination.
11. The system of claim 10 , wherein said detector identifies a noise ripple level in a frequency range.
12. The system of claim 11 , wherein said detector includes a band-pass filter.
13. The system of claim 11 , wherein said detector identifies a noise ripple level in a frequency range based on harmonics and/or sub-harmonics of a frequency of operation of a power converter in said powered device.
14. The system of claim 11 , wherein said detector determines whether a current ripple level exceeds said threshold level.
15. The system of claim 11 , wherein said detector determines whether a voltage ripple level exceeds said threshold level.
16. The system of claim 15 , wherein said threshold level is defined by IEEE 802.3af.
17. The system of claim 10 , wherein said controller shuts down said delivery of power to said port.
18. The system of claim 10 , wherein said cable is an Ethernet cable.
19. The system of claim 10 , wherein said threshold level is defined in a profile.
20. A power sourcing equipment system that is configured to deliver power to a valid powered device via a cable, wherein a validity of said powered device is determined using a detection process by said power sourcing equipment system, comprising:
a detector that determines, while said power sourcing equipment system delivers power to said valid powered device via said cable, whether a noise ripple level represented by a periodic variation of a voltage level on said cable exceeds a threshold level; and
a controller that modifies a delivery of power to said valid powered device based on said determination.