Bidirectional inline power port

• US 8,447,995 B2
• Filed: 08/26/2010
• Issued: 05/21/2013
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Biederman, Daniel, Coley, Kenneth, Schindler, Frederick R.
• Primary Examiner(s): Zaman, Faisal M
• Application Number:
  US12/869,383
• Publication Number:
  US 20100325449A1
• Time in Patent Office: 999 Days
• Field of Search: 713/300, 713/310, 713/330
• 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: H04L 12/10 Current supply arrangements

Abstract

A method and apparatus for bidirectional provision of inline power over data telecommunications cabling permits power to be received at a local powered device (PD) from remote power sourcing equipment (PSE) via at least one conductor at a first time and power to be provided by the local device to a remote device or another device at a second different time.

Claims

1. An apparatus comprising:

a network port;

power supply circuitry constructed and arranged to provide power to remote devices;

power receiving circuitry constructed and arranged to receive power from a remote device;

a battery configured to provide power to the power supply circuitry and receive power from the power receiving circuitry; and

a controller configured to selectively couple the power supply circuitry and power receiving circuitry to the networking port based on a mode of operation, wherein;

in a first mode of operation, the controller is configured to simultaneously couple the power supply circuitry to the network port and decouple the power receiving circuitry from the network port, wherein;

coupling the power supply circuitry to the network port includes closing a first electrical switch from an open state between the power supply circuitry and the network port; and

decoupling the power receiving circuitry from the network port includes opening a second electrical switch from a closed state between the power receiving circuitry and the network port;

in a second mode of operation, the controller is configured to simultaneously couple the power receiving circuitry to the network port and decouple the power supply circuitry from the network port, wherein;

coupling the power receiving circuitry to the network port includes closing the second electrical switch from an open state between the power receiving circuitry and the network port; and

decoupling the power supply circuitry from the network port includes opening the first electrical switch from a closed state between the power supply circuitry and the network port; and

the controller is configured to select between the first mode of operation and the second mode of operation by;

selecting the first mode of operation when the network port is connected to a remote network device that requests remote power and the battery is in a charged state; and

selecting the second mode of operation when the network port is connected to a remote network device that provides remote power and the battery is in an uncharged state.

2. The apparatus of claim 1 wherein:

the controller is further configured to select a third mode of operation when the network port is neither connected to a remote network device that requests remote power nor a remote network device that provides remote power; and

in the third mode of operation, the controller is configured to simultaneously decouple the power receiving circuitry from the network port and decouple the power supply circuitry from the network port.

3. The apparatus of claim 1 wherein:

the controller is further configured to select a third mode of operation when the apparatus powers itself; and

in the third mode of operation, the controller is configured to simultaneously couple the power receiving circuitry to the network port and couple the power supply circuitry to the network port.

4. The apparatus of claim 1 wherein the network port is a multi-conductor network port.

5. The apparatus of claim 4 wherein the multi-conductor network port is an Ethernet port.

6. The apparatus of claim 1 wherein the network port is configured to couple to a network cable having a plurality of twisted pairs of wires, at least one twisted pair of wires of the plurality of twisted pairs of wires configured to concurrently convey both data and direct current power between the apparatus and the remote network device.

7. The apparatus of claim 1 wherein:

when the power supply circuitry is coupled to the network port in the first mode of operation, the power supply circuitry is configured to supply a particular voltage to the network port for provision of power to the remote network device that requests remote power; and

when the power receiving circuitry is coupled to the network port in the second mode of operation, the remote network device that provides remote power is configured to supply the same particular voltage for provision of power to the power receiving circuitry via the network port.

8. A method performed by a network device, the network device including a network port, power supply circuitry, power receiving circuitry, a battery configured to provide power to the power supply circuitry and receive power from the power receiving circuitry, and a controller, the method comprising:

choosing, at the controller, which of a plurality of modes of operation the network device should operate in, wherein choosing includes;

selecting a first mode of operation when the network port of the network device is connected to a remote network device that requests remote power and the battery is in a charged state; and

selecting a second mode of operation when the network port is connected to a remote network device that provides remote power and the battery is in an uncharged state; and

selectively coupling the power supply circuitry of the network device and the power receiving circuitry of the network device to the network port of the network device based on the chosen mode of operation, wherein selectively coupling includes;

in the first mode of operation, simultaneously coupling the power supply circuitry to the network port and decoupling the power receiving circuitry from the network port, wherein;

coupling the power supply circuitry to the network port includes closing a first electrical switch from an open state between the power supply circuitry and the network port; and

decoupling the power receiving circuitry from the network port includes opening a second electrical switch from a closed state between the power receiving circuitry and the network port; and

in the second mode of operation simultaneously coupling the power receiving circuitry to the network port and decoupling the power supply circuitry from the network port, wherein;

coupling the power receiving circuitry to the network port includes closing the second electrical switch from an open state between the power receiving circuitry and the network port; and

decoupling the power supply circuitry from the network port includes opening the first electrical switch from a closed state between the power supply circuitry and the network port.

9. The method of claim 8 wherein:

choosing further includes selecting a third mode of operation when the network port is neither connected to a remote network device that requests remote power nor a remote network device that provides remote power; and

selectively coupling includes, in the third mode of operation, simultaneously decoupling the power receiving circuitry from the network port and decoupling the power supply circuitry from the network port.

10. The method of claim 8 wherein:

choosing further includes selecting a third mode of operation when the apparatus powers itself; and

selectively coupling includes, in the third mode of operation, simultaneously coupling the power receiving circuitry to the network port and coupling the power supply circuitry to the network port.

11. The method of claim 8 wherein the network port is a multi-conductor network port.

12. The method of claim 11 wherein the multi-conductor network port is an Ethernet port.

13. The method of claim 8 wherein the network port is configured to couple to a network cable having a plurality of twisted pairs of wires, at least one twisted pair of wires of the plurality of twisted pairs of wires configured to concurrently convey both data and direct current power between the network device and the remote network device.

14. The method of claim 8 wherein:

coupling the power supply circuitry to the network port in the first mode of operation further includes supplying a particular voltage from the power supply circuitry to the network port for provision of power to the remote network device that requests remote power; and

coupling the power receiving circuitry to the network port in the second mode of operation further includes receiving the same particular voltage at the power receiving circuitry via the network port from the remote network device that provides remote power.