Background of the Invention
The invention relates to the transitional termination of a plurality of multiconductor cables in a single terminal connector. More particularly, the invention relates to the transition and termination of four individual electrical transmission cables into a single pin-socket connector by utilizing a bus bridge on a single substrate bar printed circuit board which eliminates the need for a multilayered printed circuit board.
Heretofore, in order to terminate four multiconductor cables into a single terminal connector, it has been necessary to utilize a printed circuit board constructed in at least three layers. Multiple levels of interconnect must be made through the layers in order to terminate and route the various signal and ground conductors from the four cables without shorting and signal interference. This process and construction is both expensive and time consuming in manufacturing and assembly.
Circuit boards have been generally known which employ conductive strips which straddle the circuit board for special purposes such as shown in U.S. Pat. No. 4,314,312 wherein a programmed insulator is placed between the contacts of the conductive strip and the circuit board to provide a selected circuit pattern.
Summary of the Invention
The above objectives are accomplished according to the present invention by providing a transitional printed circuit board which includes first and second electrical planes on opposing sides of an insulating substrate. Each electrical plane includes a first ground plane adjacent a rear edge of the circuit board, and first electrical lands spaced from the first ground plane. Second electrical lands are spaced from the first electrical lands. Electrical traces interconnect the first and second lands. A ground bus bar bridge spans the electrical traces in a nonconductive manner. A series of electrical termination pads interconnect with the first and second electrical lands with a terminal connector. A first cable is terminated on the first electrical plane by connecting signal wires from the first cable to the first electrical lands, and connecting ground wires of the first cable at the first ground plane. A second cable is terminated on the first electrical plane by connecting signal wires from the second cable to the second lands, and connecting ground wires of the second cable to the second ground plane. A third cable is terminated on the second electrical plane by terminating signal wires of the third cable at the first electrical lands on the second electrical plane of the transitional circuit board. The ground wires of the third cable are terminated at the first ground plane on the second plane. A fourth cable is terminated by connecting signal wires of the fourth cable at the second electrical lands on the second electrical plane of the transitional printed circuit board, and terminating ground wires of the fourth cable at ground bus bar bridges .
Description of the Drawings
The construction designed to carry out the invention will hereinafter be described, together with other features thereof.
The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and wherein:
FIG. 1 is a perspective view illustrating a transitional terminal printed circuit board for transitioning and terminating four multiconductor flat electrical transmission cables in accordance with the present invention;
FIG. 2 is a section view taken along line 2--2 of FIG. 1;
FIG. 3 is a top plan view illustrating a first electrical plane of a transitional printed circuit board for terminating a plurality of multiconductor transmission cables in accordance with the present invention; and
FIG. 4 is a plan view of an opposite side of the printed circuit board of FIG. 3 illustrating a second electrical plane for terminating a plurality of multiconductor transmission cables.
Description of a Preferred Embodiment
Referring now to the drawings, the invention is illustrated wherein a printed circuit (PC) board is illustrated generally at 10 which includes a substrate 12. The substrate of the PC board includes two sides 12a and 12b. Side 12a includes a first electrical plane or layer A for transitionally terminating two flat woven electrical transmission cables into a pin-socket terminal connector. Side 12b includes a second electrical plane or layer B for transitionally terminating two additional flat woven electrical transmission cables into a pin-socket terminal connector in a manner to be explained more fully in detail hereinafter. While the PC board may be utilized with only two cables terminating on only one side of the PC board, it is in making transition of four cables into a terminal connector that the invention is most particularly advantageous.
As can best be seen in FIG. 3, the first side 12a of substrate 12 includes a first electrical plane A which includes first and second electrical contact means in the form of a plurality of electrically conductive lands 14, and a second plurality of electrically conductive lands 16 which are spaced form lands 14 and interconnected by a plurality of electrical traces 18. Lands 14 and 16 are arranged in spaced rows 14a, 16a. Electrical termination means includes a series of termination pads 22 which are connected to lands 16 by electrical traces 20. A series of plated-through holes 24 are formed through the substrate 12 in a manner that some of traces 20 may be programmed to terminate at opposite side 12b of PC board 10.
First electrical plane A on side 12a of substrate 12 includes a generally U-shaped ground plane 26 having a first ground plane section 26a formed as a leg along peripheral edge 10d of PC board 10, and a second ground plane section 26b formed as a leg along peripheral edge 10b. An interconnecting ground plane section 26d extends along peripheral edge 10a of PC board 10 and interconnects the ground sections 26a and 26b.
A second ground plane in the form of a bus bar bridge 28 spans electrical traces 18 in a superposed position in a manner that electrical signals transmitted along traces 18 are not shorted by a grounded bus bar 29 forming part of the bridge. Bus bar bridge 28 is connected at end 28a to ground section 26a and at end 28b to ground plane section 26b. A layer of insulation 30, preferably in the form of a tape, surrounds the conductive bus bar 29 of the bus bar bridge 28. The insulation insulates traces 18 of the PC board below and the signal wires which may pass over the bus bar 29 (FIGS. 1 and 2).
As can best be seen in FIG. 4, second electrical plane B is defined on side 12b of the PC board 10 which includes first and second electrical contact means in the form of a first plurality of electrically conductive lands 32, and a second plurality of electrically conductive lands 34. Lands 32 are spaced from lands 34 and are interconnected by electrical traces 36. Lands 32 and 34 are arranged in respective spaced rows 32a and 34a. There exists plated through holes 24 in the second electrical plane B to which the desired ones of traces 40 may be connected.
Electrical termination means for connecting lands 32 and 34 to the terminal connector includes a series of termination pads 42 which connect directly to the prongs of the pin sockets of the terminal connector 52. Plated through holes 24 may be programmed to connect traces 20 or 40 to opposing sides.
There is a ground plane 41 formed on side 12b of substrate 12 in the form of a generally U-shaped ground plane around the peripheral edges of PC board 10 coextending with ground plane 26. Ground plane 41 includes a first ground plane section 41a extending along peripheral edge 10b, and a second ground plane section 41b extending as a leg along peripheral edge 10d. There is a third ground plane section 41d interconnecting legs 41a and 41b extending along rearward edge 10a of PC board 10 (FIG. 4).
Referring to FIGS. 2 and 4, there is a second ground plane provided in the second electrical plane B by a bus bar bridge 43 which spans electrical traces 36 to prevent shorting of signals transmitted to traces 36. Bus bar bridge 43 is terminated at ends 43a and 43b to ground plane sections 41a and 41b, respectively. A layer of insulation 45 surrounds bus bar 47 of bus bar bridge 43.
The electrically conductive lands and traces and terminating pads may be formed on opposing sides of the substrate in any conventional manner. For example, a laminated layer of copper may be etched and removed to create the small electrical areas of lands, traces, pads and ground planes forming electrical planes A and B on opposing sides of substrate 12 (FIGS. 3 and 4).
In accordance with transitional terminal PC board 10 of the present invention, as can best be seen in FIG. 1, there is a first cable 44, a second cable 46, a third cable 48, and a fourth cable 50 which are all transitionally terminated and connected to a single terminal connector 52. The transition of the cables to the connector is made by means of the aforedescribed electrical planes. Each of the cables is illustrated in the form of a woven electrical transmission cable having a plurality of signal conductors and ground conductors arranged juxtaposed and bound in a weave pattern in a conventional manner.
The ground wires 44a from first cable 44 are terminated at a bus bar bridge 28, and signals 44b from cable 44 are terminated at the lands 16. Ground wires 46a from second cable 46 are terminated at ground plane section 26d, and signal wires 46b are terminated at lands 14. Bus bar bridge 28 spans above traces 18 in a manner not to short out signals from cable 46.
In accordance with the invention, the bus bar bridges 28 and 43 are connected to a common ground with ground planes 26 and 41 via wrap-around pigtail connectors 54.
Ground signals 50a of cable 50 are terminated at bus bar bridge 43, and signal wires 50b of cable 10 are terminated at lands 34. Ground wires 48a of cable 48 are terminated at ground plane section 41d, and signal wires 48b at lands 32. Bus bar bridge 43 spans above traces 36 in a manner that signals 50b are not shorted.
Electrical traces 20 connected to lands 16 in the first electrical plane may be connected to desired ones of the pads 22 or plated holes 24 in accordance with a prescribed program for termination to electrical connector 52. Likewise, traces 40 connected to lands 34 in the second electrical plane are routed either to a pad 42 or plated-through holes 24 in accordance with the prescribed termination program. Plated through holes 24 may be utilized to terminate conductors in one electrical plane to the pads in the opposite electrical plane. Connector 52 includes prongs 52a and 52b electrically connected to pads 22 and 42, respectively, such as by soldering. Prongs 52a and 52b are connected to pin sockets 54a and 54b of terminal connector 52. A cover 56 may be fastened about the transitionally terminated cables and PC board as shown in dotted lines.
There is electrical insulation 60 arranged between signal wires 46b of cables 46 and ground plane 26. Insulation 60 also insulates signal wires 48b and ground plane 41, and may be any suitable electrical insulation tape. Thus, it can be seen that an advantageous simplistic construction can be had for a transitional PC board for terminating four individual woven flat electrical transmission cables in accordance with the invention. The need for a multilayered circuit board with various levels of interconnect requiring complexity in construction and in connecting the four cables is eliminated.
While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.