Method and apparatus distributing power to a load in a powered device

• US 7,471,014 B2
• Filed: 09/01/2006
• Issued: 12/30/2008
• Est. Priority Date: 09/01/2006
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Karam, Roger, Seto, Kan-Chiu, Lum, Meilissa R.
• Primary Examiner(s): Jackson; Stephen W
• Assistant Examiner(s): KAPLAN, HAL IRA
• Application Number:
  US11/514,606
• Publication Number:
  US 20080054720A1
• Time in Patent Office: 851 Days
• Field of Search: 307/82, 307/83
• US Class Current: 307/83
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources

Abstract

A powered device, such as an IP telephone, includes power converter electronics that allows the powered device to couple to multiple power sources and receive a relatively large amount of power (e.g., 15 W or greater) from any single power source or from any combination of the power sources. For example, the powered device can connect to a first power source and a second power source by a cable having four twisted pairs of conductors where a first two-pair set of conductors couples the powered device to the first power source and a second two-pair set of conductors couples the powered device to the second powered device. In use, the converter circuitry can provide power to the load from either the first power source via the first two-pair set of conductors, the second power source via the second two-pair set of conductors, or from both power sources via both the first and second two-pair sets of conductors.

Claims

1. A powered device operable to receive power via a communication medium, the powered device comprising:

first interface electronics operable to receive power from a first power source by a first two sets of twisted pair conductors and second interface electronics operable to receive power from a second power source by a second two sets of twisted pair conductors;

power converter electronics having;

first primary windings electrically coupled to the first interface electronics,

second primary windings electrically coupled to the second interface electronics, and

secondary windings electrically coupled to the first primary windings and to the second primary windings; and

a load electrically coupled to the secondary windings, the power converter electronics being operable to provide power to the load from one of (i) the first interface electronics and the first two sets of twisted pair conductors, (ii) the second interface electronics and the second two sets of twisted pair conductors, and (iii) both the first interface electronics and the first two sets of twisted pair conductors and the second interface electronics and the second two sets of twisted pair conductors;

the power converter electronics further comprises;

a first controller electrically coupled to the first primary windings, the first controller configured to control power delivery to the secondary windings via the first primary windings; and

a second controller electrically coupled to the second primary windings, the second controller configured to control power delivery to the secondary windings via the second primary windings; and

further comprising a communications circuit electrically coupled to the first controller and the second controller, the communications circuit configured to;

detect a first amount of current drawn by the first primary windings;

detect a second amount of current drawn by the second primary windings;

compare the first amount of current to the second amount of current; and

based upon the comparison, when the first amount of current drawn is not substantially equal to the second amount of current drawn, transmit a signal to at least one of the first controller and the second controller to adjust an amount of current drawn such that the first amount of current drawn by the first primary windings and the second amount of current drawn by the second primary windings are substantially equal;

a power detector operable to detect whether power is provided by a first of two sets of twisted pair conductors, by a second of two sets of twisted pair conductors, or from both the first of two sets of twisted pair conductors and the second of two sets of twisted pair conductors;

wherein the power detector comprises;

first primary detector windings electrically coupled to the first primary windings and operable to detect a transfer of power between the first primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the first primary windings and the secondary windings;

second primary detector windings electrically coupled to the second primary windings and operable to detect a transfer of power between the second primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the second primary windings and the secondary windings; and

secondary detector windings electrically coupled to the first primary detector windings and to the second primary detector windings and electrically coupled to a signal output, the secondary detector windings configured to receive the reporting signal from at least one of the first primary set of detector windings and the second primary set of detector windings and transmit the reporting signal to the signal output.

2. In a powered device, a method for providing power to a powered device load, comprising:

electrically coupling first interface electronics to a first power source by a first two sets of twisted pair conductors, the first interface electronics electrically coupled to first primary windings and secondary windings;

electrically coupling second interface electronics to a second power source by a second two sets of twisted pair conductors, the second interface electronics electrically coupled to second primary windings and the secondary windings;

providing power to the powered device load electrically coupled to the secondary windings from one of (i) the first interface electronics and the first two sets of twisted pair conductors, (ii) the second interface electronics and the second two sets of twisted pair conductors, and (iii) both the first interface electronics and the first two sets of twisted pair conductors and the second interface electronics and the second two sets of twisted pair conductors;

controlling power delivery to the secondary windings via the first primary windings by a first controller electrically coupled to the first primary windings;

controlling power delivery to the secondary windings via the second primary windings by a second controller electrically coupled to the second primary windings;

detecting, by a communications circuit electrically coupled to the first controller a first amount of current drawn by the first primary windings to the secondary windings;

detecting, by the communications circuit electrically coupled to the second controller, a second amount of current drawn by the second primary windings to the secondary windings;

comparing, by the communications circuit, the first amount of current drawn to the second amount of current drawn; and

based upon the comparison, when the first amount of power is not substantially equal to the second amount of power, transmitting a signal to at least one of the first controller and the second controller to adjust the amount of current drawn such that the first amount of current drawn by the first primary windings to the secondary windings and the second amount of current drawn by the second primary windings are substantially equal;

comprising detecting, by a power detector, a connection condition associated with the powered device, the connection condition indicating one of the power being provided by a first two sets of twisted pair conductors, the power being provided by a second two sets of twisted pair conductors, or the power being provided from both the first two sets of twisted pair conductors and the second two sets of twisted pair conductors;

detecting, by first primary detector windings electrically coupled to the first primary windings, a transfer of power between the first primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the first primary windings and the secondary windings;

detecting, by second primary detector windings electrically coupled to the second primary windings, a transfer of power between the second primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the second primary windings and the secondary windings; and

receiving, by secondary detector windings electrically coupled to the first primary set of detector windings and to the second primary set of detector windings and electrically coupled to a signal output, the reporting signal from at least one of the first primary set of detector windings and the second primary set of detector windings and transmitting the reporting signal to the signal output.

3. A powered device operable to receive power via a communication medium, the powered device comprising:

first interface electronics operable to receive power from a first power source by a first two sets of twisted pair conductors and second interface electronics operable to receive power from a second power source by a second two sets of twisted pair conductors;

power converter electronics having;

first primary windings electrically coupled to the first interface electronics,

second primary windings electrically coupled to the second interface electronics, and

secondary windings electrically coupled to the first primary windings and to the second primary windings;

a load electrically coupled to the secondary windings, the power converter electronics being operable to provide power to the load from both the first interface electronics and the first two sets of twisted pair conductors and the second interface electronics and the second two sets of twisted pair conductors; and

a logic circuit configured to;

detect a first amount of current drawn by the first primary windings;

detect a second amount of current drawn by the second primary windings;

compare the first amount of current to the second amount of current; and

based upon the comparison, when the first amount of current drawn is not substantially equal to the second amount of current drawn, adjust the amount of current drawn such that the first amount of current drawn by the first primary windings and the second amount of current drawn by the second primary windings are substantially equal;

a power detector operable to detect whether power is provided by a first of two sets of twisted pair conductors, by a second of two sets of twisted pair conductors, or from both the first of two sets of twisted pair conductors and the second of two sets of twisted pair conductors;

wherein the power detector comprises;

first primary detector windings electrically coupled to the first primary windings and operable to detect a transfer of power between the first primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the first primary windings and the secondary windings;

second primary detector windings electrically coupled to the second primary windings and operable to detect a transfer of power between the second primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the second primary windings and the secondary windings; and

secondary detector windings electrically coupled to the first primary detector windings and to the second primary detector windings and electrically coupled to a signal output, the secondary detector windings configured to receive the reporting signal from at least one of the first primary set of detector windings and the second primary set of detector windings and transmit the reporting signal to the signal output.

4. A powered device operable to receive power via a communication medium, the powered device comprising:

first interface electronics operable to receive power from a first power source by a first two sets of twisted pair conductors and second interface electronics operable to receive power from a second power source by a second two sets of twisted pair conductors;

power converter electronics having;

first primary windings electrically coupled to the first interface electronics,

second primary windings electrically coupled to the second interface electronics, and

secondary windings electrically coupled to the first primary windings and to the second primary windings;

a load electrically coupled to the secondary windings, the power converter electronics being operable to provide power to the load from one of (i) the first interface electronics and the first two sets of twisted pair conductors, (ii) the second interface electronics and the second two sets of twisted pair conductors, and (iii) both the first interface electronics and the first two sets of twisted pair conductors and the second interface electronics and the second two sets of twisted pair conductors;

a power detector operable to detect whether power is provided by a first of two sets of twisted pair conductors, by a second of two sets of twisted pair conductors, or from both the first of two sets of twisted pair conductors and the second of two sets of twisted pair conductors; and

the power detector comprising;

first primary detector windings electrically coupled to the first primary windings and operable to detect a transfer of power between the first primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the first primary windings and the secondary windings;

second primary detector windings electrically coupled to the second primary windings and operable to detect a transfer of power between the second primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the second primary windings and the secondary windings; and

secondary detector windings electrically coupled to the first primary detector windings and to the second primary detector windings and electrically coupled to a signal output, the secondary detector windings configured to receive the reporting signal from at least one of the first primary set of detector windings and the second primary set of detector windings and transmit the reporting signal to the signal output.

5. The powered device of claim 4, further comprising:

a capacitor electrically coupled to the first interface electronics and disposed between a first set of the two sets of twisted pair conductors and a second set of the two sets of twisted pair conductors; and

a capacitor electrically coupled to the second interface electronics and disposed between a first set of the two sets of twisted pair conductors and a second set of the two sets of twisted pair conductors.

6. The powered device of claim 4, wherein the communications circuit is further in electrical communication with the secondary windings, the communications circuit configured to:

detect an output voltage from the secondary windings, the output voltage corresponding to a power output of the secondary windings;

compare the output voltage with a threshold voltage to generate an indicator value; and

(i) when the indicator value has a first value, continue to detect the output voltage and compare the output voltage with the threshold voltage and (ii) when the indicator value has a second value, transmit a signal to at least one of the first controller and the second controller, the signal causing at least one of the first controller and the second controller to increase a pulse width of the power provided to the load.

7. The powered device of claim 6, comprising an opto-isolator electrically coupled to the secondary windings and disposed between the secondary windings and the communications circuit.

8. The powered device of claim 4, wherein:

the first interface electronics are operable to receive power from the first power source where the first power source is a first power source controller of a power source device and the second interface electronics are operable to receive power from the second power source where the second power source is a second power source controller of the power source device; and

the powered device is operable to receive a classification signal from the power source device, the classification signal operable to verify connection of the power source device to the powered device by the first two sets of twisted pair conductors configured to carry power between the power source device and the powered device and by the second two sets of twisted pair conductors configured to carry power between the power source device and the powered device.

9. The powered device of claim 4, wherein the power converter electronics are operable to provide power to the load from the first power source, the second power source, or both the first power source and second power source.

10. The powered device of claim 4, wherein the power converter electronics are operable to provide greater than about 12 W of power to the load.

11. The powered device of claim 4, wherein the powered device is configured as an Internet Protocol (IP) telephone.

12. In a powered device, a method for providing power to a powered device load, comprising:

electrically coupling first interface electronics to a first power source by a first two sets of twisted pair conductors, the first interface electronics electrically coupled to first primary windings and secondary windings;

electrically coupling second interface electronics to a second power source by a second two sets of twisted pair conductors, the second interface electronics electrically coupled to second primary windings and the secondary windings; and

providing power to the powered device load electrically coupled to the secondary windings from one of (i) the first interface electronics and the first two sets of twisted pair conductors, (ii) the second interface electronics and the second two sets of twisted pair conductors, and (iii) both the first interface electronics and the first two sets of twisted pair conductors and the second interface electronics and the second two sets of twisted pair conductors;

detecting, by a power detector, a connection condition associated with the powered device, the connection condition indicating one of the power being provided by a first two sets of twisted pair conductors, the power being provided by a second two sets of twisted pair conductors, or the power being provided from both the first two sets of twisted pair conductors and the second two sets of twisted pair conductors;

detecting, by first primary detector windings electrically coupled to the first primary windings, a transfer of power between the first primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the first primary windings and the secondary windings;

detecting, by second primary detector windings electrically coupled to the second primary windings, a transfer of power between the second primary windings and the secondary windings and in response to detecting a transfer of power, generate a reporting signal indicating the transfer of power between the second primary windings and the secondary windings; and

receiving, by secondary detector windings electrically coupled to the first primary set of detector windings and to the second primary set of detector windings and electrically coupled to a signal output, the reporting signal from at least one of the first primary set of detector windings and the second primary set of detector windings and transmitting the reporting signal to the signal output.

13. The method of claim 12, wherein the communications circuit is in electrical communication with the secondary windings, the method further comprising:

detecting an output voltage from the secondary windings, the output voltage corresponding to a power output of the secondary windings;

comparing the output voltage with a threshold voltage to generate an indicator value; and

(i) when the indicator value has a first value, continuing to detect the output voltage and compare the output voltage with the threshold voltage and (ii) when the indicator value has a second value, transmitting a signal to at least one of the first controller and the second controller, the signal causing at least one of the first controller and the second controller to increase a pulse width of the power provided to the load.

14. The method of claim 13, wherein, wherein detecting comprises detecting the output voltage from an opto-isolator electrically coupled to the secondary windings and disposed between the secondary windings and the communications circuit.

15. The method of claim 12, comprising:

receiving, by the first interface electronics, power from the first power source where the first power source is a first power source controller of a power source device and the second interface electronics is operable to receive power from the second power source where the second power source is a second power source controller of the power source device; and

receiving, by the powered device, a classification signal from the power source device, the classification signal operable to verify connection of the power source device to the powered device by the first cable having two sets of twisted pair conductors configured to carry power between the power source device and the powered device and by the second cable having two sets of twisted pair conductors configured to carry power between the power source device and the powered device.

16. The method of claim 12, wherein providing comprises providing, by the power converter electronics, power to the load from one of the first power source, the second power source, and both the first power source and second power source.