Method and system for distributing power to networked devices

• US 7,921,306 B2
• Filed: 02/16/2007
• Issued: 04/05/2011
• Est. Priority Date: 12/12/2003
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Dove, Daniel J.
• Primary Examiner(s): Lee; Thomas
• Assistant Examiner(s): Rahman; Fahmida
• Application Number:
  US11/707,682
• Publication Number:
  US 20080077811A1
• Time in Patent Office: 1,509 Days
• Field of Search: 713/300, 713/310, 713/330, 713/340, 713320-324, 700/286, 700/295, 700/297
• US Class Current: 713/300
• CPC Class Codes: G06F 1/266 Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 52/0277 according to available power supply, e.g. switching off when a low battery condition is detected
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

One embodiment disclosed relates to a system for power distribution to network devices. The system includes a plurality of network switches each having an internal power supply and a plurality of ports for connecting to the network devices and an external power supply having a plurality of output ports for connecting to the network switches. The external power supply communicates power available to the network switches. Each network switch determines amounts and priority levels of power for the network devices connected thereto, sums together the amounts at each priority level, determines additional amounts and priority levels of power required beyond the internal power supply capability, and sends a power request to the external power supply. The external power supply allocates power to the network switches depending on the power requests received.

Claims

1. A method of power distribution of direct current (DC) power over twisted pair cabling to network devices, the method comprising:

determining amounts and priority levels of power for the network devices connected via said twisted pair cabling to each ethernet switch of a plurality of ethernet switches;

summing together the amounts at each priority level at each said ethernet switch of said plurality of ethernet switches;

determining additional amounts and priority levels of power required beyond a capability of an internal power supply of each said ethernet switch of said plurality of ethernet switches; and

communicating a power request to an external power supply for the additional amounts and priority levels of power required beyond the capability of the internal power supply of each said ethernet switch of said plurality of ethernet switches.

2. The method of claim 1, further comprising allocating power by the external power supply to the ethernet switches depending on the communicated power request.

3. The method of claim 1, wherein available power and power requests are communicated using a serial data connection between the external power supply and each said ethernet switch.

4. The method of claim 1, further comprising:

arbitration between the ethernet switches to determine the power request.

5. The method of claim 4, wherein the arbitration comprises a master-slave arbitration procedure.

6. The method of claim 4, wherein the arbitration comprises a peer-to-peer arbitration procedure.

7. A method of distributing direct current (DC) power to network devices over twisted pair cabling, the method comprising:

associating an amount and priority level of power for each device of said devices connected via said twisted pair cabling to a port of a network switch;

maintaining in the switch a table of the amount and priority level for each switch port;

summing together the amounts of power for the devices connected to the network switch;

determining additional amounts and priority levels of power required beyond a capability of an internal power supply in the network switch;

communicating a power request to an external power supply for the additional amounts and priority levels of power required beyond the capability of the internal power supply in the network switch; and

using the table to allocate available power to higher priority devices when insufficient power is available to fully power all of the connected devices.

8. The method of claim 7, wherein the allocation of power is controlled using current control switches connected to the switch ports.

9. The method of claim 8, wherein the allocation of power is further controlled using a power multiplexer circuit which is configured to connect to the internal power supply within the switch and to the external power supply.

10. The method of claim 8, further comprising:

detecting actual power amounts drawn by the network devices using current sensors coupled to the switch ports.

11. The method of claim 10, wherein if an actual power drawn from a specific port exceeds authorized power to that port, then the current switch associated with the port is open to halt the power drawn therefrom.

12. The method of claim 7, wherein the priority level of power for a switch port depends on which type of network device is connected to the port.

13. The method of claim 12, wherein the higher priority devices include IP-enabled telephone devices.

14. The method of claim 12, wherein the higher priority devices include at least one wireless access point.

15. The method of claim 7, wherein the priority levels of power for switch ports are manually configurable into the table by a network administrator.