Increased power for power over ethernet applications

• US 20060112288A1
• Filed: 11/24/2004
• Published: 05/25/2006
• Est. Priority Date: 11/24/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Schindler, Frederick R.
• Granted Patent: US 7,373,528 B2
• Time in Patent Office: Days
• 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

Abstract

According to one embodiment of the invention, a method for supplying power over Ethernet includes determining whether a first port of power sourcing equipment is supply current to a power over Ethernet device in a predetermined current range. The method also includes logically connecting a second port of the power sourcing equipment to the power over Ethernet device in response to determining that a first port of the power sourcing equipment is supplying current to the power over Ethernet device. The method also includes supplying power from the second port to the power over Ethernet device.

Claims

1. A method for supplying power over Ethernet comprising:

determining that a first port of power sourcing equipment is supplying current to a power over Ethernet device in a predetermined current range;

in response to determining that a first port of the power sourcing equipment is supplying current to the power over Ethernet device in a predetermined current range, electrically connecting a second port of the power sourcing equipment to the power over Ethernet powered device; and

supplying power from the second port to the power over Ethernet device.

2. The method of claim 1, and further comprising detecting the power over Ethernet device in response to determining that the first port of the power sourcing equipment is supplying current to the power over Ethernet device in a predetermined range.

3. The method of claim 2, and further comprising detecting the power over Ethernet device by determining whether a resistance level seen by the second port is within a predetermined resistance range.

4. The method of claim 3, and further comprising classifying the power over Ethernet device in response to determining whether a resistance level seen by the second port is within a predetermined range.

5. The method of claim 1, wherein determining that a first port of a power supply is supplying current to a power over Ethernet powered device comprises measuring a voltage drop through a resistor disposed between the first port and the power over Ethernet powered device.

6. The method of claim 1, wherein electrically connecting a second port of the power device to the power over Ethernet powered device comprises switching a switch disposed between the second port and the power over Ethernet device.

7. The method of claim 6, wherein the switch is a MOSFET.

8. The method of claim 3, wherein determining that a resistance level seen by the second port is within a predetermined resistance range comprises reverse biasing at least one diode disposed between the second port and the power over Ethernet powered device, thereby isolating the power over Ethernet device from the second port, and exposing the second port to a resistance level within the predetermined resistance range.

9. The method of claim 8, wherein exposing the second port to a resistance level comprises exposing the second port to a resistor having a value approximately equal to a resistance of the power over Ethernet powered device.

10. The method of claim 1, wherein the power over Ethernet device is selected from the group consisting of an IP phone, a computer, a wireless network access point, and a docking station.

11. The method of claim 1, wherein the power over Ethernet powered device requires more than 12.95 watts.

12. An apparatus comprising:

a current detection circuit operable to determine whether a first port of power sourcing equipment is supplying current to a power over Ethernet powered device;

a switching circuit operable to receive an indication from the current detection circuit that the first port of the power sourcing equipment is supplying current to a power over Ethernet powered device, and, in response, electrically connect a second port of the power sourcing equipment to the power over Ethernet powered device; and

a detection circuit operable to mimic a valid power over Ethernet device.

13. The apparatus of claim 12, wherein the detection circuit comprises a resistance element operable to mimic a resistance of the power over Ethernet device that is seen by the second port.

14. The apparatus of claim 12, wherein the current detection system comprises a resistor and an amplifier operable to measure a voltage drop across the resistor.

15. The apparatus of claim 12, wherein the switching circuit comprises a MOSFET.

16. The apparatus of claim 12, wherein the resistance element comprises a resistor.

17. The apparatus of claim 16, wherein the detection circuit comprises at least one reverse-biased diode connected to the resistor such that current is prevented from flowing to the power over Ethernet powered device from the second port but allowed to flow through the resistor from the second port, thereby allowing detection of a valid power over Ethernet powered device by mimicking the resistance of the power over Ethernet powered device.

18. The apparatus of claim 12, wherein the power over Ethernet powered device is selected from the group consisting of an IP phone, a computer, a wireless network access point, and a docking system.

19. The apparatus of claim 12, and further comprising the power over Ethernet powered device and wherein the power over Ethernet powered device is operable to receive power from the first and second ports of the power sourcing equipment.

20. The apparatus of claim 12, wherein the current detection circuit and switching circuit are disposed within a housing having two ports mechanically configured to couple to two adjacent ports of the power sourcing equipment, thereby hindering the provision of power from two independent power supplies.

21. The apparatus of claim 20, wherein the detection circuit is disposed within the housing.

22. An apparatus comprising:

a current detection means for determining whether a first portion of power sourcing equipment is supplying current to a power over Ethernet powered device;

a switching means for receiving an indication from the current detection means that the first port of the power sourcing equipment is supplying current to the power over Ethernet powered device and, in response, electrically connect a second port of the power sourcing equipment to the power over Ethernet powered device; and

a detection means for mimicking a valid power over Ethernet device.

23. The apparatus of claim 22, and further comprising the power over Ethernet powered device, and wherein the power over Ethernet powered device is operable to receive power from the first and second ports of the power sourcing equipment.

24. The apparatus of claim 22, and further comprising a housing means for housing the current detection means and the switching means and for hindering the provision of power from two independent power supplies.

25. The apparatus of claim 24, when the detection means is disposed within the housing means.

26. A power over Ethernet system comprising:

power sourcing equipment having first and second ports operable to provide power;

an adapter for facilitating the delivery of power from the power sourcing equipment comprising;

a current detection circuit operable to determine whether a first port of the power sourcing equipment is supplying current to a power over Ethernet powered device;

a switching circuit operable to receive an indication from the current detection circuit that the first port of the power sourcing equipment is supplying current to a power over Ethernet powered device and, in response, electrically connect the second port of the power sourcing equipment to the power over Ethernet device; and

a detection circuit operable to mimic a valid power over Ethernet powered device; and

the power over Ethernet powered device coupled to the adapter.

27. The power over Ethernet system of claim 26, wherein the power sourcing equipment is operable to classify the power over Ethernet device and selectively supply power over one or both of the first and second ports based on the classification.

28. The power over Ethernet system of claim 26, wherein the power over Ethernet powered device includes at least one diode operable to isolate the second port from the power over Ethernet powered device when the at least one diode is reversed-biased.

29. The power over Ethernet system of claim 28, wherein the power over Ethernet powered device includes at least one input resistor in series with the at least one diode for regulating the amount of current flowing through the diode.

30. The power over Ethernet system of claim 26, wherein the first and second ports each include a diode for providing an AC disconnect.

31. A power over Ethernet system comprising:

a power sourcing equipment means for supplying power;

adapter means for facilitating the delivery of power from the power sourcing equipment means, the adapter means including;

a current detection means for determining that a first part of the power sourcing equipment is supplying current to a power over Ethernet powered device;

a circuit switching means for receiving an indication from the current detection means that the first port of the power sourcing equipment is supplying current to a power over Ethernet powered device and, in response, electrically connect a second port of the power sourcing equipment to the power over Ethernet device; and

a detection means for mimicking a valid power over Ethernet device; and

the power over Ethernet powered device for receiving power from the adapter means.