1. Field of the Invention
The invention relates generally to cable interconnection at the backplane of computers.
2. Description of the Related Art
Modern electronic systems such as computer systems, telephonic switches and the like, often include large circuit boards called backplane boards that are rack mounted or retained in cabinets and are electrically connected to a number of smaller circuit boards called daughter cards. Various functions on the daughter cards are transferred between cards via the backplane. Examples of such configurations may be found in U.S. Pat. Nos. 6,824,391, 6,267,604, and 6,171,115.
It will be appreciated that improvements in making connections to backplanes would be desirable.
According to an aspect of the invention, a low electrical loss interconnection is provided at a backplane.
According to another aspect of the invention, an interconnection provides ability to enhance the existing backplane capability by allowing additional circuitry external of the backplane.
According to yet another aspect of the invention, custom configuration capability is added by point-to-point ordering.
According to still another aspect of the invention, an interconnection allows easy changes to the backplane circuitry in the laboratory during product development.
According to a further aspect of the invention, an interconnection provides a low profile, allowing close panel enclosure.
According to a still further aspect of the invention, an interconnection reduces the backplane complexity, allowing for lower backplane cost.
According to another aspect of the invention, an interconnection enables cabling to the front panel of the enclosure as well as the backpanel or external direct.
According to yet another aspect of the invention, an interconnection provides the ability to attach a high bandwidth probe to the backplane circuitry.
According to still another aspect of the invention, an interconnection provides point-to-point interconnect capability.
According to a further aspect of the invention, an interconnection enhances existing backplane capabilities.
According to a still further aspect of the invention, an interconnection provides low attenuation in point-to-point connection.
According to other aspects, permanent holddowns are provided for deployment in vibration environs, a low profile allows close panel enclosure, an interconnection could reduce complexity of backplane thus lowering cost, and an interconnection allows cabling to front panel as well as backpanel or I.O. direct.
According to other aspects, an interconnection includes one or more cable wafer captures (holddowns) that have one or more of a radius limit, a retention function, retention by screws, and the ability to disable a latching function.
According to yet other aspects, an interconnection includes a shroud that has one or more of polarization left and right, polarization of power, and elevation to allow circuit board use up to (adjacent to) a backplane connector.
According to still other aspects, a wafer of an interconnection includes one or more of a snap feature for coupling together multiple wafers, cable egress and strain relief, stacking of latch arms of stacked wafers, polarization features, a latch feature for engaging a shroud, such as apertures in the shroud, a stress limiter, and an alignment feature using pins or posts.
According to another aspect of the invention, a backplane cable interconnection includes: a shroud for surrounding contacts of a backplane; cable end modules installed in slots of the shroud, wherein each of the cable end modules includes: a printed circuit board having contact pads for engaging the contacts of the backplane; one or more cables having conductors that are coupled to the contact pads; and an overmold on the printed circuit board that mechanically couples the one or more cables to the printed circuit board; and holddowns that are mechanically coupled to the shroud to retain the cable end modules in the slots. The holddowns disable a release feature of the cable end modules that would allow release of the cable end modules from the slot.
According to yet another aspect of the invention, a cable end module including: a printed circuit board having contact pads; one or more cables having conductors that are coupled to the contact pads; and an overmold on the printed circuit board that mechanically couples the one or more cables to the printed circuit board. The overmold includes a protrusion and a protrusion-receiving recess on opposite sides. The protrusion snaps into the protrusion-receiving recess of an adjacent of an adjacent cable end module.
According to still another aspect of the invention, a shroud for surrounding contacts of a backplane, the shroud including: a main body having slots therein for receiving stacked cable end modules; and a pair of side brackets at opposite ends of the main body. The main bodies has pairs of latch windows corresponding to respective of the slots, for receiving protrusions of the cable end modules when the modules are inserted into the slots. The side brackets keep the main body away from the backplane when the shroud is installed on the backplane.
To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.
The annexed drawings, which are not necessarily to scale, show various aspects of the invention.
A backplane cable interconnection is used to engage a backplane connector on a backplane. The backplane cable interconnection includes a shroud that that fits around the backplane connector, and a series of cable end modules that are inserted into the shroud. The shroud and the modules are used in place of rear transition modules. Such rear transition modules are fundamentally very expensive because of size and complexity; and, therefore, are not easily replaced with new designs. Also, backplane circuitry, such as that in rear transition modules, has electrical losses that are greater than cable losses. The present interconnection satisfies a need that exists for a connection method that will allow backplane circuit rerouting with small electrical losses, while allowing the ability to be easily changed without large investment. Also, a need exists for a backplane interconnection that will allow direct cabling between the backplane and the enclosure or between the backplane and an adjacent enclosure. Additionally, a need exists for a backplane interconnection that allows discrete probing of backplane circuitry by providing access at the backplane position. All of these advantages are provided by the interconnection described below.
The present cable interconnection allows ultimate flexibility when either cabling daughter-card position to daughter-card position, point-to-point, or when incorporating cable I/O from the backplane. This utility recognized the need for laboratory development experimentation and for ultimately deployable product having certain unique functions.
For example, it has long been recognized that circuit board attenuation exceeds cable attenuation by a large margin-sometimes 10:1. Certain critical electrical paths would benefit from cable interconnection. Also, products can be easily reconfigured by cabling rather than redoing an expensive backplane circuit board. Additionally, cables can go from the backplane to the enclosure panel, either front or back, and then to the outside world. Alternatively cables can go directly from the backplane to the outside world. Obviously, these improvements are of substantial value.
Referring now to
With reference now in addition to
The shroud main body 30 has a series of vertical slots 34 separated by partitions 36 extending into the interior space of the main body 30 from side walls 38 of the main body 30. Each of the slots 34 is configured to receive one of the wafers 16, for engagement with the contacts of the connector 6 at the bottom of the slot 34. The separate slots 34 aid in keeping the wafers 16 properly spaced and positioned, even when several wafers 16 are stacked together and inserted as a unit.
The side walls 38 of the shroud body 30 have latch windows 44, a series of rectangular (square) holes in the side walls for receiving a latching mechanism of the waters 16, as described further below. Each of the slots 34 has one of the latch windows on each side, for securing the wafer 16 placed in that slot 34.
Corners of a top wall 46 of the body 30 have tapped holes 48 therein. The tapped holes 48 are for receiving screws 52 that secure the brackets 18 and 20 to the shroud 14.
Other pads 62 are coupled to a conductive shield plane or ground plane 72 that is on a back side of the circuit board 60. The ground plane 72 is a conductive material that is placed on the back side of the circuit board, in a manner similar to the placement of the contact pads 62 and conductive traces on the front side of the circuit board 60. Electrical contact between the ground plane 72 and some of the contact pads 66 is made through vias in the circuit board 60 that are filled with conductive material.
A molded plastic piece or body 76 is heat staked onto the circuit board 60. The plastic piece 76 includes a central body portion 78, and a pair of arms 82 and 84. The plastic piece or body 76 may be made of any of a variety of suitable plastics, for example suitable thermoplastics. In addition the arms 82 and 84 provide features to secure the wafer 16 to the shroud 14. Further, there are locating features on both the central body portion 78 and the arms 82 and 84 to aid in stacking multiple of the wafers 16 together, and to move the arms 82 and 84 of a stack of wafers 16 together.
The arms 82 and 84 are able to flex relative to the central body portion 78. The arms 82 and 84 have respective latch protrusions 86 and 88 for engaging the latch windows 44 of the shroud 14. The latch protrusions 86 and 88 have ramped bottom surfaces so that the arms 82 and 84 flex inward on their own as the wafer 16 is inserted into the shroud 14. The latch protrusions 86 and 88 have squared-off upper surfaces such that once the latch protrusions 86 and 88 are engaged with the latch windows 44 they remain so engaged unless the arms 82 and 84 are pressed inward to disengage. This may be done by pressing inward on upper (distal) arm portions 92 and 94. The upper arm portions 92 and 94 extend above the shroud side walls 38 when the wafer 16 is installed in the shroud 14.
The arms 82 and 84 are thinner than the central body portion 78. This is to allow for the thickness of the shroud partitions 36, which are between the arms 82 and 84 of adjacent of the wafers 16, but are not between bodies 78 of adjacent of the wafers 16. The arms 82 and 84 may have about half the thickness of the body portion 78.
A top surface 102 of the plastic piece or body 76 has a pair of body protrusions (pins) 104 that line up with and fit into corresponding body recesses 106 on a bottom surface 108 of the plastic piece or body 76. The fitting of the body pins 104 into the body recesses 106 of an adjacent wafer 16 aids in aligning the adjacent wafers 16 as the wafers 16 are stacked, as shown in
The top surface 102 also has protrusions (pins) 114 on the upper arm portions 92 and 94, with corresponding recesses 116 on the bottom surface 108, located at corresponding locations on the upper arm portions 92 and 94. With reference to
Considering now in addition
The wafers 16 can be inserted into the shroud 14 either individually or stacked in groups. Groups of the wafers 16 may be snapped together and inserted as a unit.
With the explanation of the features of the shroud 14 and the wafer 16 now complete,
Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
This application claims priority under 35 USC 119 to U.S. Provisional Application No. 61/296,635, filed Jan. 20, 2010, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61296635 | Jan 2010 | US |