Methods and apparatus providing advanced classification for power over ethernet

• US 8,572,413 B2
• Filed: 03/31/2011
• Issued: 10/29/2013
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Karam, Roger A., Jones, Chad M., Schindler, Frederick Roland
• Primary Examiner(s): TRAN, VINCENT HUY
• Application Number:
  US13/077,515
• Publication Number:
  US 20110179302A1
• Time in Patent Office: 943 Days
• Field of Search: 713/300, 713/340
• US Class Current: 713/300
• CPC Class Codes: G01R 21/00 Arrangements for measuring electric power or power factor G01R7/12 takes precedence

Abstract

A system conducts a plurality of cycles on the powered device. Each cycle has a detection phase and a classification phase. A classification voltage is applied to the conductors during each cycle. The system measures a current in the conductors while the classification voltage is applied. The system determines a final class responsive to a plurality of measured currents. The final class utilized to determine an amount of inline power to deliver to the powered device.

Claims

1. A method for classifying power sourcing equipment coupled to a powered device, the powered device configured to receive inline power from the power sourcing equipment in a wired network having at least two pairs of conductors coupling the powered device and the power sourcing equipment, the method comprising:

detecting a classification process on the at least two pairs of conductors of the powered device, the process comprising a detection phase, a classification phase, and a signature phase following the classification phase;

a classification phase voltage being detected on the conductors during the classification phase, and wherein a current is drawn from the conductors while the classification voltage is detected;

a signature phase voltage being detected on the conductors during the signature phase, and wherein a magnitude of the signature phase voltage has an upper bound below a lower bound of a magnitude of the classification voltage and a lower bound above a magnitude of a reset level of the powered device; and

identifying a type of the power sourcing equipment based on the signature phase voltage.

2. The method of claim 1, wherein identifying a type of the power sourcing equipment further comprises identifying the power sourcing equipment as a non-IEEE 802.3af power sourcing equipment that is compatible with the IEEE 802.3af standard.

3. The method of claim 2, wherein the non-IEEE 802.3af power sourcing equipment can provide more inline power to the powered device relative to an IEEE 802.03af power sourcing equipment.

4. The method of claim 1, wherein the signature phase voltage enables the powered device to recognize that the powered device has previously completed the classification phase.

5. The method of claim 1, wherein the signature phase has a predefined duration, the signature phase voltage being detected on the conductors during the predefined duration of the signature phase.

6. A powered device adapted to operate in conjunction with coupled power sourcing equipment so that the powered device can receive inline power from the power sourcing equipment in a wired network having at least two pairs of conductors coupling the powered device and the power sourcing equipment, the powered device comprising:

circuitry responsive to a classification process on the at least two pairs of conductors, the process having a detection phase, a classification phase, and a signature phase following the classification phase, wherein the process is generated by the power sourcing equipment, and the circuitry configured to;

present a current over the conductors to the power sourcing equipment responsive to a classification voltage applied during the classification phase of the process,

detect a signature phase voltage on the conductors during the signature phase, wherein a magnitude of the signature phase voltage has an upper bound below a lower bound of a magnitude of the classification voltage and a lower bound above a magnitude of a reset level of the powered device, and

identify a type of the power sourcing equipment based on the signature phase voltage.

7. The powered device of claim 6, wherein identifying a type of the power sourcing equipment further comprises identifying the power sourcing equipment as a non-IEEE 802.3af power sourcing equipment that is compatible with the IEEE 802.3af standard.

8. The powered device of claim 7, wherein the non-IEEE 802.3af power sourcing equipment can provide more inline power to the powered device relative to an IEEE 802.03af power sourcing equipment.

9. The method of claim 6, wherein the signature phase voltage enables the powered device to recognize that the powered device has previously completed the classification phase.

10. The powered device of claim 6, wherein the signature phase has a predefined duration, the signature phase voltage being detected on the conductors during the predefined duration of the signature phase.

11. A system comprising:

a power sourcing equipment;

a powered device;

a wired network having at least two pairs of conductors coupling the powered device and the power sourcing equipment; and

a memory on the powered device, the memory is encoded with a power source equipment classifying application that when executed on a processor configures the processor to perform an operation for classifying the power source equipment, the operation including;

detecting a classification process on the at least two pairs of conductors coupled to the powered device, the process having a detection phase, a classification phase, and a signature phase following the classification phase;

a classification voltage being detected on the conductors during the classification phase, and wherein a current is drawn from the conductors while the classification voltage is detected;

a signature phase voltage detected on the conductors during the signature phase, and wherein a magnitude of the signature phase voltage has an upper bound below a lower bound of a magnitude of the classification voltage and a lower bound above a magnitude of a reset level of the powered device; and

identifying a type of the power sourcing equipment based on the signature phase voltage.

12. The system of claim 11, wherein identifying a type of the power sourcing equipment further comprises identifying the power sourcing equipment as a non-IEEE 802.3af power sourcing equipment that is compatible with the IEEE 802.3af standard.

13. The system of claim 12, wherein the non-IEEE 802.3af power sourcing equipment can provide more inline power to the powered device relative to an IEEE 802.03af power sourcing equipment.

14. The method of claim 11, wherein the signature phase voltage enables the powered device to recognize that the powered device has previously completed the classification phase.

15. The system of claim 11, wherein the signature phase has a predefined duration, the signature phase voltage being detected on the conductors during the predefined duration of the signature phase.