System and method for controlling power delivered to a powered device based on channel impediments

• US 20080129118A1
• Filed: 11/30/2006
• Published: 06/05/2008
• Est. Priority Date: 11/30/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Diab, Wael William
• Granted Patent: US 8,576,873 B2
• Time in Patent Office: Days
• US Class Current: 307/35
• CPC Class Codes: H04L 12/10 Current supply arrangements

Abstract

A system and method for discovering channel impediments for Power over Ethernet (PoE) applications. Cabling power loss in PoE applications 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, discontinuities, etc.) of the Ethernet cable to enable determination of the cable resistance. The determined resistance can be used in powering decisions and in adjusting power budgets allocated to power source equipment ports.

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 an existence of connectors in the middle of said Ethernet cable, said existence being indicated by said measured electrical characteristics.

2. The power over Ethernet system of claim 1, wherein said cable detection component measures discontinuities in said Ethernet cable.

3. The power over Ethernet system of claim 1, wherein said power controller controls said power allocation based on a cable type, cable length, and said existence of connectors.

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

5. The power over Ethernet system of claim 1, wherein said power controller controls an allocation of power based on a validation of said Ethernet cable.

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

7. A power over Ethernet method, comprising:

upon connection of a powered device to a power source equipment port via an Ethernet cable, determining whether connectors exist in a middle of said Ethernet cable based on measured electrical characteristics; and

allocating a power budget to said power source equipment port, said allocated power budget being based on said determination.

8. The method of claim 7, wherein said determining comprises measuring discontinuities in said Ethernet cable.

9. The method of claim 7, wherein said allocated power budget is based on a cable type, cable length, and an existence of connectors in the middle of said Ethernet cable.

10. A power over Ethernet method, comprising:

determining whether connectors exist in a middle of an Ethernet cable that connects a powered device to power source equipment based on measured electrical characteristics of said Ethernet cable; and

determining whether to power said powered device based on said determination.

11. The method of claim 10, wherein said powering determination is for Ethernet cabling greater than 100 meters.

12. The method of claim 10, wherein said powering determination is for use of Category 3 cabling in a power over Ethernet plus application.

13. The method of claim 10, wherein said powering determination is also based on a type and length of said Ethernet cable.

14. The method of claim 10, wherein said determining is based on an identification of discontinuities in said Ethernet cable.