High-speed data cable with shield connection

• US 9,324,478 B2
• Filed: 08/29/2013
• Issued: 04/26/2016
• Est. Priority Date: 04/14/2009
• Status: Active Grant

• Current Assignee: Spectra7 Microsystems Ltd.
• Original Assignee: Spectra7 Microsystems Ltd.
• Inventors: Horan, John Martin, McGowan, David, McDaid, Padraig
• Primary Examiner(s): Mayo, III, William H
• Application Number:
  US14/014,187
• Publication Number:
  US 20140000924A1
• Time in Patent Office: 971 Days
• Field of Search: 174/36, 174/74.R, 174/74.A, 174/75.B, 174/76, 174/77, 333/90, 333/174, 333/175, 333/98
• US Class Current: 1/1
• CPC Class Codes: H01B 11/1091 with screen grounding means, e.g. drain wires
• CPC Class Codes: H01B 13/22 Sheathing; Armouring; Screening; Applying other protective layers H01B13/32 takes precedence
• CPC Class Codes: H01B 9/006 Constructional features relating to the conductors
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49169 Assembling electrical component directly to terminal or elongated conductor

Abstract

A high speed cable with terminating assemblies at the respective ends of the cable includes a ground wire, one or more signal wires, and a conductive layer enclosing the ground wire and the signal wires. The ground wire as well as the signal wires and the conductive layer extend into the terminating assemblies, in each of which corresponding inductive elements are coupled between the conductive layer and the ground wire. In each terminating assembly, the ground wire is shunted to the conductive layer by inductive elements, thus providing added low frequency connectivity in the cable, while at the same time blocking high frequency noise energy that may be present in the ground wire and preventing it from being coupled into, and transmitted through, the conductive layer.

Claims

1. A cable comprising:

a raw cable having first and second cable ends, the raw cable comprising a signal wire, a ground wire, and a conductive layer enclosing the ground wire and the signal wire;

a first inductive element coupled between the conductive layer and the ground wire at the first cable end; and

a second inductive element coupled between the conductive layer and the ground wire at the second cable end.

2. The cable of claim 1, wherein the first and second inductive elements provide conductive paths in parallel with the ground wire to shunt DC and low-frequency signals to ground at the first and second cable ends.

3. The cable of claim 1, wherein inductance values of the first and second inductive elements are substantially the same.

4. The cable of claim 1, wherein the first inductive element is selected so as to provide a first resistance that is greater than a resistance of the ground wire at an electromagnetic frequency of interest.

5. The cable of claim 1, wherein the first and second inductive elements include at least one of the following:

an inductor; and

a ferrite bead.

6. The cable of claim 1, wherein the first and second inductive elements have inductance values selected from following:

60 nH;

from about 30 nH to about 300 nH.

7. The cable of claim 1, wherein at least one of the first and second inductive elements includes an inductor formed on a printed circuit board (PCB) in one of the following ways:

mounted on the PCB;

implemented directly as tracks on the PCB.

8. The cable of claim 1, wherein the conductive layer is a shield comprising at least on one of the following:

a conductive braid; and

a conductive foil.

9. The cable of claim 1, wherein the raw cable further includes a power wire enclosed by the conductive layer.

10. The cable of claim 9, wherein:

the power wire has a diameter that is substantially the same or larger than a diameter of the ground wire.

11. The cable of claim 9, wherein:

the power wire is disposed approximately in a center of the raw cable.

12. The cable of claim 9, wherein:

the ground wire comprises two or more ground wires;

the signal wire comprises two or more signal wires; and

the signal wires are located in a space between the conductive layer and the power wire.

13. The cable of claim 12, wherein the signal wires are circumferentially arranged around the power conductor and separated by the ground wires.

14. The cable of claim 9, wherein a diameter of the signal wire is substantially the same as the diameter of the ground wire.

15. The cable of claim 1, wherein the raw cable includes at least two signal wires comprising one or more of the following:

a shielded twisted pair (STP);

an unshielded twisted pair (UTP).

16. The cable of claim 1, the cable being one of the following:

a Universal Serial Bus (USB) 3.0 cable;

a High-Definition Multimedia Interface (HDMI) cable.

17. The cable of claim 1, wherein the signal wire is shielded in a coaxial structure having a shield.

18. The cable of claim 17, further comprising an inner conductive layer enclosed by and insulated from the conductive layer, wherein the inner conductive layer includes a power wire.

19. A method for forming a cable including a raw cable having first and second cable ends, the raw cable comprising a signal wire, a ground wire, and a conductive layer enclosing the ground wire and the signal wire, the method comprising:

reducing the resistance of the ground wire in the raw cable, comprising;

electrically coupling a first inductive element with the conductive layer and the ground wire at the first cable end; and

electrically coupling a second inductive element with the conductive layer and the ground wire at the second cable end.

20. The method of claim 19, wherein the first and second inductive elements provide conductive paths in parallel with the ground wire to shunt DC and low-frequency signals to ground at the first and second cable ends;

and

wherein the first and second inductive elements provide resistances greater than a resistance of the ground wire at an electromagnetic frequency of interest.