Reduced Guard Band for Power Over Ethernet

• US 20080114998A1
• Filed: 11/05/2007
• Published: 05/15/2008
• Est. Priority Date: 11/12/2006
• Status: Active Grant

• Current Assignee: Microsemi Corp. - Analog Mixed Signal Group, Ltd. (Microchip Technology Incorporated)
• Original Assignee: Microsemi Corp. - Analog Mixed Signal Group, Ltd. (Microchip Technology Incorporated)
• Inventors: FERENTZ, Alon, BLAUT, Roni, KAHN, Simon, PINCU, David
• Granted Patent: US 7,895,456 B2
• Time in Patent Office: Days
• US Class Current: 713/324
• CPC Class Codes: H04L 12/10 Current supply arrangements
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof

Abstract

A method of controlling a power over Ethernet system, the method comprising: sequentially powering a plurality of powered devices over communication cabling; determining a first total power consumption responsive to the powering of the plurality of powered devices; in the event that the determined first total power consumption exceeds a predetermined maximum power level, disabling power from at least one of the powered plurality of powered devices thereby reducing power consumption to less than the predetermined maximum power level; responsive to the disabling power, defining a connection power limit lower than the maximum power level by a guard band; monitoring a second total power consumption subsequent to the disabling power; and enabling power to a powered device only in the event the monitored second total power consumption is less than the connection power limit.

Claims

1. A method of controlling a power over Ethernet system, the method comprising:

sequentially powering a plurality of powered devices over communication cabling;

determining a first total power consumption responsive to said powering of said plurality of powered devices;

disabling, in the event that said determined first total power consumption exceeds a predetermined maximum power level, power from at least one of said powered plurality of powered devices thereby reducing power consumption to less than said predetermined maximum power level;

defining, responsive to said disabling power, a connection power limit lower than said maximum power level by a guard band;

monitoring a second total power consumption subsequent to said disabling power; and

enabling power to a powered device only in the event said monitored second total power consumption is less than said connection power limit.

2. A method according to claim 1, further comprising:

determining the power consumption of said at least one powered device being disabled.

3. A method according to claim 2, wherein said guard band is a function of said determined power consumption of said at least one powered device having said power disabled.

4. A method according to claim 1, further comprising:

setting said guard band to zero after a predetermined period from said disabling power.

5. A method according to claims 1, further comprising:

detecting an unpowered powered device associated with a higher priority than the priority associated with said at least one powered device having said power disabled; and

setting, responsive to said detected powered device, said guard band to zero.

6. A method according to claim 1, further comprising:

detecting a request to increase allocated power to a powered device associated with a higher priority than the priority associated with said at least one powered device having said power disabled; and

setting, responsive to said detected request, said guard band to zero.

7. A method according to claim 1, further comprising in the event said monitored second total power consumption is less than said connection power limit, setting said guard band to zero.

8. A method according to claim 1, wherein said at least one powered device having said power disabled comprises one of:

a last powered device of said sequentially powered plurality of powered devices; and

a lowest priority powered device of said sequentially powered plurality of powered devices.

9. A method according to claim 1, wherein said enabling power comprising increasing an allocated power to said powered device.

10. A method according to claim 1, further comprising determining the power consumption when powered of each of said disabled at least one powered device, and wherein said defined connection power limit is associated with each powered device having said power disabled, said defined connection power limit being defined individually for each disabled at least one powered device as a function of said determined power consumption.

11. A method of controlling a power over Ethernet system, the method comprising:

sequentially powering a plurality of powered devices over communication cabling, each of said powered plurality of powered devices being associated with a unique port;

determining a total power consumption responsive to said powering of said plurality of powered devices;

disabling power, in the event that said determined total power consumption exceeds a predetermined maximum power level, from one of said plurality of powered devices;

defining, responsive to said disabling power, a connection power limit lower than said maximum power level by a guard band, said guard band being associated with the unique port associated with said powered device having said power disabled;

monitoring total power consumption subsequent to said disabling power; and

powering, in the event said monitored total power consumption subsequent to said disabling power is less than said connection power limit, said powered device having said power disabled.

12. A method according to claim 11, further comprising:

detecting that no powered device is connected to the unique port associated with said powered device having said power disabled; and

setting, responsive to said detecting that no powered device is connected, said guard band to zero.

13. A method according to claims 11, further comprising:

setting said guard band to zero responsive to one of;

said monitored total power consumption being less than said connection power limit; and

a predetermined period elapsing from said disabling power.

14. A power over Ethernet manager, comprising:

a power over Ethernet control circuitry;

a plurality of ports, each of said ports having associated therewith one of a switch and a variable current limiter responsive to said power over Ethernet control circuitry; and

at least one power sensor, in communication with said power over Ethernet control circuitry, and operative to sense an amount of power drawn via each of said plurality of ports,

said power over Ethernet control circuitry being operative to;

sequentially power a plurality of powered devices each connected to particular one of said plurality of ports over communication cabling;

determine, via said at least one power sensor, a first total power consumption responsive to said sequentially powered plurality of powered devices;

disable, in the event that said determined first total power consumption exceeds a predetermined maximum power level, via the operation of said associated one of a switch and a variable current limiter, power from at least one of said powered plurality of powered devices thereby reducing power consumption to less than said predetermined maximum power level;

define, responsive to said disabled power, a connection power limit lower than said maximum power level by a guard band;

monitor, via said at least one power sensor, a second total power consumption subsequent to said disabled power; and

enable, via said associated one of a switch and a variable current limiter, power to a powered device only in the event said monitored second total power consumption is less than said connection power limit.

15. A power over Ethernet manager according to claim 14, wherein said power over Ethernet control circuitry is further operative to:

determine the power consumption when operating of said at least one powered device being disabled.

16. A power over Ethernet manager according to claim 14, wherein said guard band is a function of said determined power consumption of said at least one powered device having said power disabled.

17. A power over Ethernet manager according to claim 14, wherein said power over Ethernet control circuitry is further operative to set said guard band to zero responsive to one of:

a predetermined time elapsing from said disabling of power; and

said monitored second total power consumption being less than said connection power limit.

18. A power over Ethernet manager according to claim 14, further comprising a detection functionality responsive to said power over Ethernet control circuitry, and wherein said power over Ethernet control circuitry is further operative to:

detect, via said detection functionality, an unpowered powered device associated with a higher priority than the priority associated with said disabled at least one powered device; and

set said guard band to zero, responsive to said detected powered device.

19. A power over Ethernet manager according to claim 14, wherein said power over Ethernet control circuitry is further operative to:

detect a request to increase allocated power to a powered device associated with a higher priority than the priority associated with said disabled at least one powered device; and

set said guard band to zero, responsive to said detected request.

20. A power over Ethernet manager according to claim 14, wherein said disabled at least one powered device comprises one of:

a last powered device of said sequentially powered plurality of powered devices; and

a lowest priority powered device of said sequentially powered plurality of powered devices.

21. A power over Ethernet manager according to claim 14, wherein said enabling of power comprises increasing an allocated power to said powered device by setting said variable current limiter.

22. A power over Ethernet manager according to claim 14, wherein said power over Ethernet control circuitry is further operative to determine, via said at least one power sensor, the power consumption of each of said disabled at least one powered device, and

wherein said defined connection power limit is associated with each powered device having said power disabled, said defined connection power limit being defined individually for each disabled at least one powered device as a function of said determined power consumption.

23. A power over Ethernet manager, comprising:

a power over Ethernet control circuitry;

a plurality of ports, each of said ports having associated therewith an electronically controlled switch responsive to said power over Ethernet control circuitry; and

at least one power sensor, in communication with said power over Ethernet control circuitry, and operative to sense an amount of power drawn via each of said plurality of ports,

said power over Ethernet control circuitry being operative to;

power a plurality of powered devices each connected to particular one of said plurality of ports over communication cabling;

determine, via said at least one power sensor, a first total power consumption responsive to said powered plurality of powered devices;

disable, in the event that said determined first total power consumption exceeds a predetermined maximum power level, via the operation of said associated electronically controlled switch, power from one of said powered plurality of powered devices;

define, responsive to said disabled power, a connection power limit for the port associated with said disabled one of said powered device, said connection power limit being lower than said maximum power level by a guard band;

monitor, via said at least one power sensor, a second total power consumption subsequent to said disabled power; and

enable, via said associated electronically controlled switch, power to said disabled one of said powered devices only in the event said monitored second total power consumption is less than said connection power limit.

24. A power over Ethernet manager according to claim 23, further comprising a detection functionality responsive to said power over Ethernet control circuitry, said power over Ethernet control circuitry being further operative to:

detect, via said detection functionality, that no powered device is connected to the port associated with said powered device having said power disabled; and

set said guard band to zero, responsive to said detection.

25. A power over Ethernet manager according to claim 23, wherein said power over Ethernet control circuitry is further operative to set said guard band to zero responsive to one of:

said monitored total power consumption being less than said connection power limit; and

a predetermined time elapsing from said disabling of power.