Patent Publication Number: US-7594820-B2

Title: Method and apparatus for electrostatic discharge of connectors

Description:
RELATED APPLICATION 
   This application is a Divisional of U.S. patent application Ser. No. 11/553,225 filed Oct. 26, 2006, now U.S. Pat. No. 7,422,455, the teachings of which are incorporated herein by reference. 

   FIELD 
   The present disclosure relates generally to systems and methods for discharging electrostatic charges, and more particularly systems and methods for discharging electrostatic charges in Ethernet connectors. 
   BACKGROUND INFORMATION 
   Many computer and electronics systems include removable and/or replaceable circuit boards. Such removable circuit boards may, for example, be in the form of computer blades, cards, etc. A typical removable circuit board or add-in card may include an Ethernet card having one or more connectors, ports or jacks (such as an RJ45 connector) that act as a physical interface between the card and another device (typically a cable such as, but not limited to, twisted pair type cables). Connectors/jacks may also be found as an integral part of a motherboard (such as, but not limited to, a laptop computer motherboard or the like) as well as other boards (such as, but not limited to, fax machines and the like. 
   Unfortunately, electrostatic charges can build up on the cable. If this electrostatic build-up is not discharged prior to making the electrical connection with the connector on the card, the electrostatic charge can be transferred from the cable to the card possibly resulting in damage to the card or other components of the electronic system. 
   Accordingly, there exists a need for an improved connector that obviates or reduces the risk of electrostatic discharge. It is important to note that the present disclosure is not intended to be limited to a system or method which must satisfy one or more of any stated objects or features of the invention. It is also important to note that the present disclosure is not limited to the preferred, exemplary, or primary embodiment(s) described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present disclosure, which is not to be limited except by the following claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Features and advantages of the claimed subject matter will be apparent from the following detailed description of embodiments consistent therewith, which description should be considered with reference to the accompanying drawings, in which: 
       FIG. 1  is a front perspective view of an I/O interface and a plug wherein the I/O interface includes one embodiment of an electrostatic discharge element according to the present disclosure; 
       FIG. 2  is a front perspective view of an I/O interface having another embodiment of an electrostatic discharge element according to the present disclosure; 
       FIG. 3  is a front perspective view of an I/O interface and a plug wherein the I/O interface includes a further embodiment of an electrostatic discharge element according to the present disclosure; 
       FIG. 4  is a front perspective view of an I/O interface having yet another embodiment of an electrostatic discharge element according to the present disclosure; 
       FIG. 5  is a front view of a computer system chassis including circuit boards with input/output (I/O) interfaces, consistent with one embodiment of the present disclosure; and 
       FIG. 6  is a side view of the computer system chassis shown in  FIG. 5 . 
   

   DETAILED DESCRIPTION 
   Consistent with the present disclosure, various embodiments of input/output (I/O) interfaces  110  which may be configured to provide a cable discharge event (CDE) and substantially discharge an electrostatic charge built-up on a cable plug  12  or the like are shown in  FIGS. 1-4 . The input/output (I/O) interfaces  110  according to the present disclosure may therefore reduce the possibility of the electrostatic charge on the plug  12  damaging either the circuit board assemblies  120  and/or another component connected to the circuit board assemblies  120 . 
   The I/O interfaces  110  may comprise a body or housing  14  of a dielectric material (such as, but not limited to, various plastics or the like) that defines a cavity  16  which may be mechanically and/or electrically connected to a circuit board  121  using any device known to those skilled in the art. The cavity  16  may be sized and shaped to accept the cable plug  12  and form an electrical connection between one or more pins  18  of the I/O interfaces  110  (which are configured to be electrically coupled to the circuit board  121 ) and the pins  20  of the plug  12 . The pins  18  may be disposed proximate a rear portion of the cavity  16  generally opposite from a notched region  35  and may be biased towards a base or center of the cavity  16 . The notched region  35  ensures that the plug  12  can only be inserted in a specific orientation with respect to the I/O interfaces  110 . 
   For sake of clarity, the present disclosure will be described wherein the I/O interface  110  comprises an RJ45 jack or port  10  configured to connect with a corresponding RJ45 plug  12 . For example, the RJ45 cable connection  110  may be defined by IEEE 802.3 (Ethernet). However, this is not a limitation of the present disclosure and the I/O interface  110  may also comprise other connections such as, but not limited to, RJ11 connections. 
   The port  10  may also comprise one or more electrostatic discharge (ESD) elements  22  which are coupled to a ground  24  and may be configured to prevent or reduce the possibility of electrostatic charge on the plug  12  from damaging the circuit board  120 . As the plug  12  is inserted into the cavity  16 , the ESD elements  22  may contact the pins  20  of the plug  12  to provide a discharge path to a ground  24 , thereby discharging any electrostatic charge that has built-up on the plug  12 . The term “ground” as used herein refers to any potential (including a zero potential or true ground) that may be used as a reference potential in a given system. According to one embodiment, the ESD elements  22  may be positioned within the cavity  16  (for example, proximate the opening of the cavity  16 ) to allow the ESD elements  22  to contact the pins  20  of the plug  12  (and therefore discharges any electrostatic charge on the plug  12 ) prior to the pins  20  of the plug  12  coming into electrical contact with the pins  18  of the port  10 . 
   The ESD elements  22  may be flexible such that the ESD elements  22  may bend or otherwise move out of the way as the plug  12  is inserted into the cavity  16  and may be biased towards the center of the cavity  16 . According to one embodiment, the ESD elements  22  may be positioned on substantially the same face of the cavity  16  as the pins  18 . Alternatively, the ESD elements  22  may be positioned on the opposite face of the cavity  16 . In either case, the ESD elements  22  may be positioned with respect to the cavity  16  such that the ESD elements  22  contact the pins  20  of the plug  12  sufficiently far enough away from the pins  18  of the port  10  to substantially eliminate the possibility of the electrostatic charge on the plug  12  arcing to the pins  18  of the port  10 . The size and position of the ESD elements  22  may be selected such the ESD elements  22  may easily contact the pins  20  of the plug  12  as the plug  12  is initially inserted into the cavity  16 , yet when the plug  12  is fully inserted into the cavity  16 , the ESD elements  22  bend or otherwise move out of the way and substantially do not contact either the pins  18 ,  20  of the port  10  or the plug  12  and therefore do not have any affect on the normal connection between the port  10  and the plug  12 . 
   According to one embodiment, the ESD elements  22 ,  FIGS. 1 and 2 , may include a single ESD element  22  made from a conductive material (such as, but not limited to, conductive metals, alloys, composites, or any material that has been doped to be conductive) disposed proximate the opening of the cavity  16  which is electrically coupled to the ground  24 , for example, by way of a conductive path  26 . The ESD element  22  may include a flexible plate or the like which is sized to electrically contact all of the pins  20  of the plug  12  as the plug  12  is inserted into the cavity  16 . According to one embodiment, the flexible plate  22   a ,  FIG. 1 , may extend substantially downwards from a first surface  23  of the cavity  16  towards the center. For example, the flexible plate  22   a  may include a first position in which the flexible plate  2   a   2  is disposed at an angle of approximately 90 degrees from the first surface  23  prior to the plug  12  being inserted into the cavity  16  and may bend or otherwise move towards a second position in which the flexible plate  22   a  is substantially parallel with the first surface  23  once the plug  12  is fully inserted into the cavity  16 . 
   Of course, the flexible plate  22  may also be disposed at other angles greater or less than 90 degrees from the first surface  23 . For example, the single ESD element  22   b ,  FIG. 2 , may be disposed substantially parallel with the first surface  23  of the cavity  16  and biased towards the center (for example by one or more springs or the like, not shown) while in the first position. As the plug  12  is inserted into the cavity  16 , the flexible plate  22   b  electrically contacts the pins  20  of the plug  12 . Once the plug  12  is fully inserted in the cavity  16 , the flexible plate  22   b  may be disposed in the second position and may pushed generally in the direction of arrow A into the housing  14  of the port  10 . 
   Consistent with other embodiments of the present disclosure, the ESD elements  22 ,  FIGS. 3 and 4 , may comprise a plurality of conductive pins, wires, or brushes  25  (hereinafter collectively referred to as “conductive brushes”). The number of the conductive brushes  25  may correspond to the number of pins  20  on the plug  12  and may be positioned/spaced such that each conductive brush  25  contacts a single pin  20 . Alternatively, the plurality of conductive brushes  25  may be more numerous than the number of pins  20  and may be formed in groups or spread substantially evenly across a surface of the cavity  16 . 
   The conductive brushes  25   a ,  FIG. 3 , may extend substantially downwards from a first surface  23  of the cavity  16  towards the center. For example, the conductive brushes  25   a  may include a first position in which the conductive brushes  25   a  may be originally disposed at an angle of approximately 90 degrees from the first surface  23  prior to the plug  12  being inserted into the cavity  16  and may bend or otherwise move towards a second position in which conductive brushes  25   a  are substantially parallel with the first surface  23  once the plug  12  is fully inserted into the cavity  16 . 
   Of course, the conductive brushes  25  may also be disposed at other angles greater or less than 90 degrees from the first surface  23 . For example, the conductive brushes  25   b ,  FIG. 4 , may be disposed substantially parallel with the first surface  23  of the cavity  16  and biased towards the center (for example by one or more springs or the like, not shown) while in a first position prior to the plug  12  being inserted into the cavity  16 . As the plug  12  is inserted into the cavity  16 , the conductive brushes  25   b  electrically contact the pins  20  of the plug  12  and may pushed generally in the direction of arrow A towards a second position wherein the conductive brushes  25   b  at least partially disposed within the housing  14  of the port  10 . 
   Referring specifically to  FIGS. 5 and 6 , one or more input/output (I/O) interfaces  110 - 1  to  110 - n  may be electrically coupled to one or more blades or circuit board assemblies  120 - 1  to  120 - n  in a computer system shelf or chassis  130  for transmitting and/or receiving a signal between a circuit board assembly  120  and another device. The circuit board assemblies  120  may include a faceplate  111  extending along at least a portion of one edge of a circuit board  121  to which the I/O interfaces  110  may be secured. The faceplate  111  may include a latching system capable of releasably coupling the circuit board assembly  120  to the chassis  130  and/or to a feature of the chassis  130  and/or a component disposed at least partially within the chassis  130 . As shown in  FIG. 6 , the circuit board assemblies  120  may be coupled to a common backplane  132  within the chassis  130  (only one circuit board assembly  120  is shown in the side view of  FIG. 2 ). The chassis  130  may also include one or more rear circuit board assemblies  134  (e.g., rear transition modules) located on a second (or rear) side of the backplane  132  opposite one or more corresponding front circuit board assemblies  120 . The rear circuit board assemblies  134  may also include one or more I/O interfaces  110   a.    
   In some embodiments, the circuit board assemblies  120  may include circuit boards  121  that provide application functionality (e.g., single blade computers, storage blades, network processing (such as, but not limited to, Ethernet cards) and I/O blades) and switch boards that provide switching interconnectivity between the node boards (e.g., fabric switches). The computer system chassis  130  may be an advanced telecommunications computing architecture (Advanced TCA or ATCA) chassis complying with or compatible with, at least in part, PCI Industrial Computer Manufacturers Group (PICMG), Advanced Telecommunications Computing Architecture (ATCA) Base Specification, PICMG 3.0 Rev. 2.0, published Mar. 18, 2005, and/or later versions of the specification (“the ATCA specification”). According to such an embodiment, the circuit board assemblies  120  may be ATCA blades complying with or compatible with, at least in part, the ATCA Specification. 
   Various other embodiments consistent with the present disclosure may include a chassis  130  and/or circuit board assemblies  120  complying with and/or compatible with technical specifications other than and/or in addition to the ATCA Specification. A circuit board assembly  120  may also be used, for example, in other types of bladed architectures including, but not limited to, VME, CompactPCI (CPCI), and IBM BladeCenter®. A circuit board assembly  120  may also be used on other computer or electronic devices that use multiple types of I/O interfaces including, but not limited to, notebook computers, desktop computers, home entertainment products, mobile products (e.g., PDAs, cell phones, MP3 players, DVD/CD players, etc.) and automotive entertainment and communication products. The scope of the present disclosure should not, therefore, be construed as being limited to any particular computer system, device, or form factor. 
   Accordingly, the present disclosure provides a method and apparatus for providing a cable discharge event (CDE) prior to the cable plug coming into electrical contact with the pins of the port. The port includes one or more electrostatic discharge (ESD) elements coupled to ground. As the cable plug is inserted into the port, the ESD elements electrically contact the cable plug (specifically the plug pins) thereby providing a discharge path to the system&#39;s ground. As the plug is fully inserted into the port, the ESD elements may move out of the way such that they are not in electrical contact with either the pins of the plug or the port and therefore have substantially no affect on the normal connection/operation of the plug and port. The circuit board (and other circuits coupled thereto) may thus be protected from potentially destructive CDE. 
   As mentioned above, the present disclosure is not intended to be limited to a system or method which must satisfy one or more of any stated or implied object or feature of the invention and should not be limited to the preferred, exemplary, or primary embodiment(s) described herein. The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as is suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the claims when interpreted in accordance with breadth to which they are fairly, legally and equitably entitled.