Compensation for high powered midspan power sourcing equipment

• US 8,195,965 B2
• Filed: 11/03/2009
• Issued: 06/05/2012
• Est. Priority Date: 11/04/2008
• Status: Active Grant

• Current Assignee: Microsemi Corp. - Analog Mixed Signal Group, Ltd. (Microchip Technology Incorporated)
• Original Assignee: Microsemi Corp. - Analog Mixed Signal Group, Ltd. (Microchip Technology Incorporated)
• Inventors: Darshan, Yair
• Primary Examiner(s): Rahman, Fahmida
• Application Number:
  US12/611,141
• Publication Number:
  US 20100115299A1
• Time in Patent Office: 945 Days
• Field of Search: 713/1, 713/300, 713/310, 713320-324, 713/330, 713/340, 361/42
• 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

A midspan unit arranged to supply power to a powered device over data communication cabling constituted of a signal conditioner exhibiting a transfer function with a gain of not less than −0.4 dB as compared with: (K1*(s+R/L1+a)^m)/((s+R/L2+b)^n) over a predetermined frequency range associated with the data transmitted from the powered device. s represents 2*π*(√−1)*f, wherein f represents the predetermined frequency range associated with the data terminal equipment to be powered. R represents the signal source impedance in parallel with the load termination impedance. L1 represents the effective inductance of a data transformer winding of the data transmitter of the powered device, the effective inductance determined responsive to power received by the powered device from the power sourcing equipment; and L2 represents the effective inductance of the data transformer winding of the data transmitter of the powered device expected by a receiver of the switch or hub equipment.

Claims

1. A midspan unit arranged to supply power for a powered device over data communication cabling, the midspan unit comprising:

a power sourcing equipment;

a signal conditioner;

a data terminal connection arranged for connection towards a powered device, the powered device arranged to receive power over data communication cabling from said power sourcing equipment, a pair of leads of said data terminal connection representing data transmitted from the powered device by a data transmitter of the powered device and further carrying at least a portion of said power, said data transmitter of the powered device having a data transformer exhibiting an effective inductance; and

a network connection arranged for connection towards a switch or hub equipment, a pair of leads of said network connection representing conditioned data transmitted to the switch or hub equipment, said switch or hub equipment exhibiting a data receiver having a load termination impedance,

said signal conditioner coupled to said pair of leads of said data terminal connection and to said pair of leads of said network connection, said signal conditioner arranged to receive said data transmitted from the powered device and output said conditioned data, said signal conditioner exhibiting a transfer function with a gain of not less than −

0.4 dB as compared with;

(K1*(s+R/L1+a)^m)/((s+R/L2+b)^n)

over a predetermined frequency range associated with the data transmitted from the powered device, wherein;

K1, m and n are factors that compensate for component accuracy and for adjusting the approximation to desired curve, and a and b are variables;

s represents 2*π

*(√

−

1)*f, wherein f represents the predetermined frequency range associated with the data transmitted from the powered device;

R represents a signal source impedance of the data transformer of the data transmitter of the powered device in parallel with the load termination impedance of the data receiver of the switch or hub equipment;

L1 represents the effective inductance of the data transformer winding of the data transmitter of the powered device, said effective inductance determined responsive to power received by the powered device over the data communication cabling; and

L2 represents the effective inductance of the data transformer winding of the data transmitter of the powered device expected by the data receiver of the switch or hub equipment.

2. The midspan unit of claim 1, wherein said signal conditioner comprises a first capacitor, a second capacitor and an inductor, said first capacitor coupled between a first lead of said pair of leads of said network connection and a first lead of said inductor, said second capacitor coupled between a second lead of said pair of leads of said network connection and a second lead of said inductor, said power sourcing equipment connected to a center tap of said inductor.

3. The midspan unit of claim 2, wherein each of said first capacitor and said second capacitor exhibit a value of about 0.1 and said inductor exhibits an effective inductance of the range of current supplied by said power sourcing equipment of 350 μ

H to 900 μ

H.

4. The midspan unit of claim 1, wherein said signal conditioner comprises a first capacitor, a second capacitor and a transformer exhibiting a first winding and a second winding, said first winding magnetically coupled to said second winding, said first capacitor coupled between a first lead of said pair of leads of said network connection and a first lead of said first winding, said second capacitor coupled between a second lead of said pair of leads of said network connection and a second lead of said first winding, said power sourcing equipment connected to a center tap of said second winding.

5. The midspan unit of claim 4, wherein each of said first capacitor and said second capacitor exhibit a value of about 0.1 μ

F and said second winding exhibits an effective inductance of the range of current supplied by said power sourcing equipment of 350 μ

H to 900 μ

H.

6. The midspan unit of claim 1, wherein L1 is about 120 μ

H and L2 is about 350 μ

H.

7. The midspan unit of claim 1, wherein K1 is about 0.995.

8. The midspan unit of claim 1, wherein m is equal to 1 and n is equal to 1.

9. The midspan unit of claim 1, wherein a is equal to 0 and b is equal to 0.

10. The midspan unit of claim 1, wherein the predetermined frequency range is 100 KHz to 1 MHz.

11. A method of providing midspan power to a powered device while allowing for data communication between a data transmitter of the powered device and a data receiver of a switch or hub equipment without excessive droop, the method comprising:

receiving data transmitted from the powered device data transmitter;

providing a signal conditioner; and

conditioning said received data by said conditioner to output conditioned data towards the data receiver of the switch or hub equipment, said signal conditioner exhibiting a transfer function with a gain of not less than −

0.4 dB as compared with;

(K1*(s+R/L1+a)^m)/((s+R/L2+b)^n)

over a predetermined frequency range associated with the data transmitted from the powered device, wherein;

K1, m and n are factors that compensate for component accuracy and for adjusting the approximation to desired curve, and a and b are variables;

s represents 2*π

*(√

−

1)*f, wherein f represents the predetermined frequency range associated with the data transmitted from the powered device;

R represents a signal source impedance of the data transmitter of the powered device in parallel with a load termination impedance of the data receiver of the switch or hub equipment, the data receiver of the switch or hub equipment arranged to receive said output conditioned data;

L1 represents an effective inductance of a data transformer winding of the powered device data transmitter, said effective inductance determined responsive to midspan power provided to the powered device; and

L2 represents an effective inductance of the data transformer winding of the powered device data transmitter expected by the data receiver of the switch or hub equipment.

12. The method of claim 11, wherein said signal conditioner comprises a first capacitor, a second capacitor and an inductor, said first capacitor coupled between a first lead of a network connection and a first lead of said inductor, said second capacitor coupled between a second lead of said network connection and a second lead of said inductor, the method further comprising connecting power to a center tap of said inductor.

13. The method of claim 12, wherein each of said first capacitor and said second capacitor exhibit a value of about 0.1 μ

F and said inductor exhibits an effective inductance of the range of current supplied by said power connected to said center tap of 350 μ

H to 900 μ

H.

14. The method of claim 11, wherein said signal conditioner comprises a first capacitor, a second capacitor and a transformer exhibiting a first winding and a second winding, said first winding magnetically coupled to said second winding, said first capacitor coupled between a first lead of a network connection and a first lead of said first winding, said second capacitor coupled between a second lead of the network connection and a second lead of said first winding, the method further comprising connecting power to a center tap of said second winding.

15. The method of claim 14, wherein each of said first capacitor and said second capacitor exhibit a value of about 0.1 μ

F and said second winding exhibits an effective inductance of the range of current supplied by said power connected to said center tap of 350 μ

H to 900 μ

H.

16. The method of claim 11, wherein L1 is about 120 μ

H and L2 is about 350 μ

H.

17. The method of claim 11, wherein m is equal to 1, n is equal to 1, a is equal to 0 and b is equal to 0.

18. The method of claim 11, wherein predetermined frequency is 100 KHz to 1 MHz.