System and method for controlling a power budget at a power source equipment using a PHY

• US 20080172564A1
• Filed: 01/16/2007
• Published: 07/17/2008
• Est. Priority Date: 01/16/2007
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Diab, Wael William, Brown, Kevin Clyde, Yousefi, Nariman
• Granted Patent: US 7,989,976 B2
• Time in Patent Office: Days
• US Class Current: 713/300
• CPC Class Codes: H04L 12/10 Current supply arrangements

Abstract

A system and method for controlling the delivery of power to a powered device in a Power over Ethernet Broad Reach (PoE-BR) application. Cabling power loss in a PoE-BR application is related to the resistance of the cable itself. A PHY can be designed to measure electrical characteristics (e.g., insertion loss, cross talk, length, etc.) of the Ethernet cable to enable determination of the cable resistance. The determined resistance in a broad reach cable can be used in increasing a power budget allocated to a power source equipment port.

Claims

1. A power over Ethernet system, comprising:

a powered device detection component that detects a presence of a powered device, said powered device coupled to a power source equipment port via an Ethernet cable;

a cable detection component that measures an electrical characteristic of said Ethernet cable; and

a power controller that controls power allocation to said power source equipment port based on a power loss determined using said measured electrical characteristics of said Ethernet cable, wherein said power allocation is increased if said power loss indicates that an existing power allocation is insufficient.

2. The power over Ethernet system of claim 1, wherein said power loss is determined using a cable type.

3. The power over Ethernet system of claim 2, wherein said power loss is determined using a cable length.

4. The power over Ethernet system of claim 1, wherein said power controller controls said power allocation based on a calculated resistance of said Ethernet cable.

5. The power source equipment of claim 1, wherein said power controller identifies a power budget allocated to said port.

6. The power source equipment of claim 1, wherein said Ethernet cable is greater than 100 meters.

7. The power source equipment of claim 1, wherein a power allocation is changed through an adjustment to a current limit.

8. A power over Ethernet method, comprising:

upon connection of a powered device to a power source equipment port via an Ethernet cable, measuring one or more electrical characteristics of said Ethernet cable; and

adjusting an allocated power budget to said power source equipment port, said adjustment being based on an estimate of a resistance of said Ethernet cable using said measurements, wherein said power budget allocation is increased if a power loss calculated using said estimated resistance indicates that an existing power allocation for said power source equipment port is insufficient.

9. The method of claim 8, wherein said resistance is based on a type of said Ethernet cable.

10. The method of claim 9, wherein said resistance is based on a length of said Ethernet cable.

11. The method of claim 8, wherein said Ethernet cable is greater than 100 meters.

12. The method of claim 8, wherein said adjusting comprises changing a current limit.

13. A power over Ethernet method, comprising:

upon connection of a powered device to a power source equipment port via an Ethernet cable, measuring one or more electrical characteristics of said Ethernet cable;

determining whether an initial power budget allocated to said power source equipment port is lower than a determined output power calculated using said measurements; and

raising said initial power budget allocated to said power source equipment port if said determined output power is greater than said initial power budget.

14. The method of claim 13, wherein said determined output power is based on a type of said Ethernet cable.

15. The method of claim 14, wherein said determined output power is based on a length of said Ethernet cable.

16. The method of claim 13, wherein said Ethernet cable is greater than 100 meters.

17. The method of claim 13, wherein said raising comprises increasing a current limit.