Abstract:
A power-coupling pad (FIG.  1, 160  or  170 ) is located on a lateral edge portion of an electronics module ( 100 ). Each power-coupling pad ( 160, 170 ) is mated with a power supply clip (FIG.  2, 240, 250 ) which is included within a side of a card guide that supports and retains the electronics module ( 100 ). The power supply clip ( 240, 250 ) can incorporate a spring which provides constant and affirmative contact with the power-coupling pad ( 160, 170 ) through a low resistance path. The power-coupling pad ( 160, 170 ) and power supply clip ( 240, 250 ) can be constructed using any suitable conductive material such as gold, nickel, lead, chromium and palladium.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to the field of electronics and, more particularly, to supplying power to electronics equipment. 
     BACKGROUND OF THE INVENTION 
     In a computerized electronic system, which includes multiple electronics modules, a backplane is used in order to provide primary power to the modules, as well as to enable each of the modules to communicate with each other and with the external environment. As backplane communications technology progresses, fewer physical connections to the backplane are required since multiconductor parallel interfaces can be replaced by high-speed interfaces. Additionally, the use of high-speed fiber interconnections further reduces the required complexity of the backplane since each of the electronics modules can communicate with each other and with the external environment using only a single fiber-optic interface. 
     However, although electronics modules need only communicate using a single fiber optic connection, thus virtually eliminating the need for a conventional backplane, a need still exists to provide primary power to the electronics module. Hence, an apparatus for coupling power to an electronics module, which does not require a conventional backplane, would be highly desirable. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is pointed out with particularity in the appended claims. However, a more complete understanding of the present invention may be derived by referring to the detailed description and claims when considered in connection with the figures, wherein like reference numbers refer to similar items throughout the figures, and: 
     FIG. 1 is a block diagram of an electronics module, which includes provisions for receiving primary power in accordance with a preferred embodiment of the invention; 
     FIG. 2 is a top view of a card guide for coupling power to the electronics module of FIG. 1 in accordance with a preferred embodiment of the invention; 
     FIG. 3 is an isometric view of a portion of the card guide of FIG. 2 which includes provisions for coupling power to an electronics module in accordance with a preferred embodiment of the invention; 
     FIG. 4 is an isometric view of an apparatus for coupling power to multiple electronics modules in accordance with a preferred embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An apparatus for coupling power to an electronics module eliminates the need to use the backplane to bring primary power to the electronics module. According to one aspect of the invention, power is instead coupled through the lateral edge portion of the electronics module through the use of power-coupling pads located on the electronics module and power supply clips located within the channel of the card guide. By using the lateral edge portion of the electronics module, the length of any board traces on the electronics module can be reduced, thus reducing the level of electromagnetic interference caused by long lead lengths of current-carrying conductors. Additionally, through the use of substantially planar coupling pads located on the module and the power supply clip located in the card guide, a less resistive primary power-coupling path can be achieved. 
     FIG. 1 is a block diagram of an electronics module which includes provisions for receiving primary power in accordance with a preferred embodiment of the invention. In FIG. 1, electronics module  100  includes electronic components  110 ,  120 ,  130 ,  140 , and  150 . These electronic components can be and type of computer electronics components such as central processing units, memory elements, bus interfaces, and related equipment. Each of these electronic components receives primary power from at least one of power-coupling pads  160  and  170  using board traces  165 ,  175 , and  185 . Electronic components  110 ,  120 ,  130 ,  140 , and  150  may communicate with each other using board traces other than those shown. This additional coupling paths can include address lines, control lines, data buses and hardware interrupts. Data connectors, such as those used for fiber optic interfaces, have not been shown for simplicity. 
     As an example, which is not intended to limit the scope of the invention, power-coupling pad  160  can be intended to convey a primary power voltage of 5 Volts to each of electronic components  110 ,  120 , and  130 . Continuing with this example, power-coupling pad  170  may be intended to convey a voltage of 12 Volts to electronic components  140 ,  150 , and  110 , where electronic component  110  requires dual voltage inputs of 5 and 12 Volts. 
     Power-coupling pads  160  and  170  are preferably located at lateral edge portion  105  of electronics module  100  within an area, which contacts a card guide when the module is inserted. In the example of FIG. 1, power-coupling pad  160  is located a distance L 1  from the lateral edge portion of electronics module  100  and a distance of L 4  from front edge  107  of the electronics module. Further in accordance with the example of FIG. 1, power-coupling pad  170  is located a distance L 2  from the lateral edge portion of electronics module  100 , and a distance L 5  from front edge  107  of the electronics module. Additionally, power-coupling pads  160  and  170  are separated by a lateral distance of L 3 . 
     It should be noted that the use of power-coupling pads  160  and  170  has on a lateral edge portion of electronics module  100  allows a greater degree of freedom in the placement of electronic components  110 ,  120 ,  130 ,  140 , and  150 . In the event that one or more of these electronics components requires a large current to operate the component, the particular component need not be placed near front edge  107  in order to reduce resistive losses. Rather, the high current component can be placed along the length of lateral edge portion  105 , thereby allowing a reduction in the associated board trace, which conveys the power to the device, such as board traces  165 ,  175 , and  185 . This can be useful in reducing the amount of radiated electromagnetic interference caused by high current signals conveyed through long board traces. 
     Power-coupling pads  160  and  170  can be comprised of a metal such as gold, palladium, nickel, chromium, lead or other suitable metal, which possesses high conductivity, as well as a degree of resistance to corrosion. Additionally, it is desirable that the metal selected for use by power-coupling pad  160  and  170  be sufficiently durable so as not to be easily abraded as a result of repeated insertion and removal of electronics module  100  into and out of the card guide of FIG.  2 . Further, power-coupling pads  160  and  170  are desirably separated by an amount equal to L 3 . This separation precludes the possibility of shorting together two power supply clips (as described in reference to FIG. 2) during insertion and removal of electronics module  100 . The possibility of shorting two power supply clips together can be further reduced by placing coupling pads  160  and  170  on both the first and second sides of electronics module  100 . 
     FIG. 2 is a top view of a card guide for coupling power to the electronics module of FIG. 1 ( 100 ) in accordance with a preferred embodiment of the invention. In FIG. 2, card entrance  220  is intended to receive a lateral edge portion of electronics module  100  as the electronics module is slid into the card guide of FIG. 2 towards front edge  207  portions. Preferably, the card guide of FIG. 2 operates mechanically in a manner similar to conventional card guides by retaining and supporting the electronics module as the module is wedged between first half  200  and second half  210 . A second card guide which incorporates the conventional electronics module support and retention features of the card guide of FIG. 2 is preferably mechanically interfaced to the opposite lateral edge portion of electronics module  100  in order to support the electronics module from both the top and bottom. 
     When electronics module  100  is inserted into the card guide of FIG. 2, power-coupling pad  170  preferably makes contact with power supply clip  240 . Similarly, power-coupling pad  160  makes contact with power supply clip  250 . Power supply clips  240  and  250  are preferably located a distance L 4  and L 5 , respectively, from front edge  207  portion of the card guide of FIG.  2 . Additionally, although not shown in the two-dimensional view of FIG. 2, power supply clip  240  is offset a distance L 2  from the deepest portion of the channel of the card guide of FIG. 2 in order to mate with power-coupling pad  170 . In a similar manner, power supply clip  250  is offset a distance L 1  from the deepest portion of the card guide in order to mate with power-coupling pad  160 . 
     FIG. 3 is an isometric view of a portion of the card guide of FIG. 2 which includes provisions for coupling power to an electronics module in accordance with a preferred embodiment of the invention. In FIG. 3, the arrangement of power supply clips  240  and  250  within the card guide of FIG. 2 can be more easily seen. As previously mentioned in reference to FIG. 2, power supply clip  240  is offset by an amount of L 2  from the deepest portion of the card guide. In a similar manner, power supply clip  250  is offset from the deepest portion of the card guide by an amount of L 1 . In order to maintain continuous and positive contact with power-coupling pads  170  and  160  of electronics module  100 , first half  200  of the card guide of FIG. 2 preferably includes a spring or other resilient element which possesses the capability recover its shape after deformation. Additionally, although shown as rectangular in nature, power supply clips  240  and  250  as well as power coupling pads  160  and  170  need not be in accordance with this shape. According to the needs of the particular application, the power supply clips and power-coupling pads may assume various other shapes such as circles, ellipses, or other suitable geometries. 
     Although FIGS. 1-3 indicate the use of power-coupling pads and power supply clips located only on a first side of an electronics module and on a corresponding first half of a card guide, nothing prevents the use of power coupling pads on the reverse side of electronics module  100 . In a similar manner, nothing precludes the use of a power supply clip located on the opposite side of the card guide of FIG.  2 . 
     FIG. 4 is an isometric view of an apparatus for coupling power to multiple electronics modules in accordance with a preferred embodiment of the invention. In FIG. 4, primary power bus  440  conveys power to electronics modules  100  and  400  by way of primary power-coupling lines  450  and  460 , respectively. In a similar manner, primary power bus  445  conveys power to electronics modules  100  by way of primary power-coupling line  470 . The use of separate primary power buses in FIG. 4 allows distinct voltages to be conveyed to each of electronics modules  100  and  400 . Thus, primary power bus  440  can convey 12 volts to electronics modules  100  and  400 , while primary power bus  445  conveys 5 V primary power to the electronics module  100 . Although the technique of power-coupling is shown as requiring wire loops, the present invention does not require this. Other conventional techniques of coupling power to the electronics modules may be used. 
     An apparatus for coupling power to an electronics module eliminates the need to use the backplane to bring primary power to the electronics module. The resulting system provides additional freedom by allowing board designers to locate high current and electromagnetic field-generating components near power-coupling pads, thus reducing resistive losses and electromagnetic fields caused by longer board traces. Additionally, through the use of substantially planar coupling pads located on the module and the power supply clip located in the card guide, a less resistive primary power coupling path can be achieved. 
     Accordingly, it is intended by the appended claims to cover all modifications of the invention that fall within the true scope and spirit of the invention.