Abstract:
There is provided an apparatus for accommodating at least two different sized cards, the apparatus comprising a card housing comprising one or more card slots, each card slot being adaptable for inserting the at least two different sized cards; and a card guide system for adapting said one or more card slots for insertion of at least one of the at least two different sized cards. There is also provided a modified mezzanine card having at least one increased non-standard physical dimension relative to a standard mezzanine card suitable for insertion in the apparatus using the card guide system.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. provisional patent application having the Ser. No. 61/007,312 filed Dec. 11, 2007, incorporated herein in its entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to an apparatus for adapting mezzanine cards and more particularly to a chassis or ATCA card design configured for use with both standard (AMC) and non-standard (AMC+) circuit cards. 
     DESCRIPTION OF THE RELATED ART 
     Modular systems are typically used in communication networks and avionic platforms where reliability and cost effectiveness are important factors. The modularity of the components in a modular system helps to reduce costs and improve reliability. A key component of a modular system is the modular platform. A modular platform includes, but is not limited to, backplanes that receive various types of circuit cards. These circuit cards may further include smaller circuit cards as front insertion Advanced Mezzanine Card (AMC) that provide additional functionality to the modular platform. 
     Typically, backplanes in modular platforms are designed to receive circuit cards that have a common design. This creates modularity by allowing circuit cards to be interchangeable in a modular platform. For example, circuit cards may be designed in compliance with the PCI Industrial Computer Manufacturers Group (PICMG), Advanced Telecommunications Computing Architecture (ATCA) Base Specification, PICMG 3.0 (hereinafter referred to as “the ATCA specification”). If circuit cards are designed to be compliant with the ATCA specification, the circuit cards will be interchangeable with other ATCA compliant circuit cards. 
     A, type of circuit card, commonly referred to as a “mezzanine carrier board,” includes interfaces for additional Input/Output capability. One type of module to be attached to a mezzanine carrier board is a front accessible module. Similar to ATCA compliant circuit cards, a front accessible module&#39;s compliance with a specification may also result in interchangeability. One example specification is the AMC Specification, PIGMG AMC.0, (hereinafter referred to as “the AMC.0 specification”). PICMG specifications are available at (www.picmg.org). 
     The AMC relates to a wide-range of high-speed mezzanine cards. AMC can be plugged into an ATCA module or standalone module within a chassis. When plugged into an ATCA module the AMC is referred to as a mezzanine card. However when the AMC is used as a standalone module in a chassis it is no longer a mezzanine card, but instead it is the primary card that is in direct communication with the backplane. 
     AMC is designed to take advantage of the strengths of the PICMG 3.0 AdvancedTCA specification and the carrier grade needs of reliability, availability, and serviceability (RAS). The AMC module is designed to be hot swappable into an ATCA card or chassis. 
     The AMC faceplate are modular and will change depending upon the Input/Output (IO) required for the particular function. Module card guides support the insertion of the modules into the AMC connectors while the AMC bay provides mechanical support as well as Electromagnetic Interference (EMI) shielding. Connectivity between the AMC module and the carrier/chassis can be provided via an AMC connector that is attached to the carrier board or backplane. The AMC utilizes an edge finger connector whose mating connector is either on a carrier board or backplane. 
     One draw back with existing AMC is that it does not physically support the capability to host a PCI Mezzanine Card (PMC) or Switched Mezzanine Card (XMC) as a sub-assembly within a Single Module size form factor. The current solutions for this situation are to use an AMC Double Module size form factor which has enough room to accommodate one or more add on cards, (e.g., PMC. XMC). However, using a Double Module AMC imposes a number of drawbacks including non-optimal chassis design which include additional cooling requirements, reduced capability to meet harsh environments, decreased reliability, increased size and increased weight. Accordingly for these reasons as well as others this solution is expensive and not favored in the industry. 
     Therefore what is needed in the industry is a capability to host a PMC or XMC on an AMC that is much smaller than the Double Module AMC. This would be highly desirable to overcome the aforementioned drawbacks which collectively contribute to an optimized design of a chassis or blade configuration. Further, having such a capability would allow a designer to be able to take advantage of the large number of PMC and/or XMC modules that are presently available in the Commercial off the shelf (COTS) market in a minimum footprint. It is always preferred to maximize the use of common or COTS components whenever possible. Additionally, there exist a class of PMCs and XMCs, such as video capture and processors that are only suitable to a niche market and as a result are also not likely to be redesigned as AMC. 
     Accordingly the present invention described below and set forth in the claims is directed to an apparatus designed to overcome the aforementioned drawbacks of devices available on the market today. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a non-standard mechanically sized AMC module, referred to herein as an AMC+ module, and an apparatus for accommodating, both the AMC+ module as well as a standard AMC module. The apparatus of the present invention includes a modified card guide system which maybe implemented in a chassis or on an ATCA card. 
     The modified card guide system of the present invention generally comprises a lower card guide assembly and an upper card guide assembly. In one embodiment, the lower card guide assembly is fixed and the upper card assembly is adjustable. In another embodiment, the lower card guide assembly is adjustable and the upper card assembly is fixed. In yet another embodiment, both the lower card guide assembly and the upper card assembly are adjustable. 
     According to an aspect of the present invention, adjustable adaptors are provided for use within each card slot of a chassis to allow a user to readily adapt any chassis slot to be configured for use with an AMC standard card/module or an AMC+ card/module as needed. 
     An advantage of the invention includes the ability to accommodate both an AMC and AMC+ modules in a single chassis or ATCA blade using a novel card/module guide system. The novel card guide system allows users to utilize both standard AMC modules as well as a novel AMC+ module within the same chassis or ATCA card. An advantage of using the AMC+ module is that it provides a capability for hosting a large pre-existing inventory of legacy add-on cards/modules, such as, for example, pre-existing commercially available PMC and/or XMC cards/modules. The ability to allow users to incorporate a large pre-existing inventory of legacy add-on cards, such as PMC and XMC daughter cards, provides enhanced functionality at modest cost, given that such cards are readily available on the COTS market. At the same time, the novel card/module guide system of the present invention is advantageously backward compatible with the standard mechanically sized AMC modules. A further advantage provided by the present invention is that it becomes unnecessary to develop an AMC module to provide a function(s) which may already exist in a PMC or XMC form factor. 
     According to an aspect of the present invention, the novel card guide system design provides an environment suitable for a novel mezzanine card of the present invention that is non-standard only with respect to its mechanical configuration (e.g., width dimension). These cards are sometimes referred to herein as AMC+ cards. The non-standard AMC+ mezzanine card/module of the present invention may, in one embodiment, be constructed to be slightly larger in its width dimension than a standard AMC card/module. For example the width dimension may be slightly increased on the order of about 0.1 to about 0.8 inches, preferably about 0.3 to about 0.6 inches, and more preferably about 0.6 inches. Using a mezzanine card that is slightly larger than a standard single-width AMC card/module overcomes the prior art limitation of using double-width mezzanine cards as add-on card hosts. 
     The present invention is further described in the drawings and the detailed description following herewith. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects, features and advantages of the invention will be apparent from a consideration of the following Detailed Description Of The Invention considered in conjunction with the drawing Figures, in which: 
         FIG. 1  representatively illustrates a prior art MicroTCA subrack. 
         FIG. 2  is a top plan view of a MicroTCA subrack in accordance with an embodiment of the invention. 
         FIG. 3  illustrates a perspective view of one exemplary embodiment of an AMC+  310  as shown in  FIG. 2 . 
         FIG. 4  is a perspective view illustrating an AMC+ module as one example of a module that may be utilized within the chassis according to embodiments of the present invention. 
         FIG. 5  is a perspective view illustrating an AMC+ module as one example of a module that may be utilized within an ATCA blade according to embodiments of the present invention. 
         FIG. 6  illustrates a number of AMC module configurations suitable for use with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description, numerous specific details are set forth, such as implementations for Advanced Mezzanine Card (AMC) cards and chassis, to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     The present invention overcomes the limitation of not being able to utilize a large pre-existing inventory of legacy products, such as PMC and XMC cards/modules, without resorting to use a standard double width AMC card/module as a host or otherwise having to design an AMC card module, either in a single or double width AMC form factor, to accommodate the functionality that presently exists within the presently available XMC or PMC form factor. 
     Accordingly, the present invention contemplates the use of a modified AMC card/module, sometimes referred to herein as an AMC+ card/module. The AMC+ card module may be characterized in that at least one dimension is slightly increased above that of a standard single width AMC card/module, which are well known in the art. It is recognized by the present invention that this increased dimension is sufficient to accommodate the large pre-existing inventory of legacy products. 
     As will be described further below, the novel AMC+ card/modules are used together with a novel optimized card guide system of the invention. The novel card guide system is flexibly suitable for use with both standard AMC card/modules and the novel AMC+ card/modules of the invention, while maintaining compliance with the AMC.0 specification, which includes features such as hot swapping, for example. Further details of the AMC.0 specification may be readily obtained from www.PICMG.org, incorporated in its entirety herein by reference. 
     While examples of the novel non-standard AMC+ card/module of the present invention are illustrated throughout the figures, it should be understood that the AMC+ card/module is described herein for purposes of illustration and explanation only. It is understood that embodiments of the present invention are generally applicable to any insertable card/module that is non-standard in at least one dimension, such as optical card/modules, transceiver card/modules, and the like. 
     The present invention is further described in connection with  FIGS. 1 through 5  and their description set forth below. 
       FIG. 1  representatively illustrates a prior art MicroTCA subrack  201 . The MicroTCA chassis  201  is an example of a typical subrack utilized in industry to provide a reference to which the present invention is to be compared. Details on MicroTCA subrack design and configurations can be found in PICMG™ MicroTCA.0. 
     The prior art MicroTCA system is a collection of interconnected elements including at least one AMC module  204  and the interconnect, MicroTCA carrier hub, power, cooling and mechanical resources need to support them. 
     A typical prior art MicroTCA system, such as the one shown in  FIG. 1 , may consist of plurality of AMC modules  204 , 14 of which are shown by way of example, coupled to a subrack  205 , and a chassis  201 . 
     With continued reference to  FIG. 1 , the single width standard AMC modules  204  shown are suitable for use with the MicroTCA chassis  201  of  FIG. 1 . These AMC modules  204  typically have dimensions of a standard size AMC module. It is noted that a drawback of the prior art MicroTCA chassis  201  is that there are no provisions in the chassis  201  or subrack  205  for accommodating AMC modules other than those of the single width or double width standard form factor sizes. The present invention overcomes this limitation as will be described below. 
       FIG. 2  representatively illustrates a MicroTCA chassis  301  in accordance with an exemplary embodiment of the present invention. For the purpose of simplicity and clarity, other components including cooling fans and ducting are not shown in  FIG. 2 . A novel card guide system of the MicroTCA chassis  301  includes a plurality of adjustable card guides  314 , one of which is shown by way of example, to accommodate the insertion of the novel AMC+ card/modules  310  of the invention into any of the available chassis slots.  FIG. 2  illustrates a single AMC+ card  310  shown in exploded view. The AMC+ card  310  is suitable for insertion into the corresponding chassis slot by utilizing adjustable card guide  314 . 
     A key feature of the invention is that the MicroTCA chassis  301  also accommodates standard AMC cards, such as AMC card  306 , shown in exploded view in  FIG. 2 . Given that the AMC card/modules  360  are of a standard mechanical configuration, when they are inserted into the MicroTCA chassis  301  they do not require the assistance of adjustable card guide  314  to accommodate their insertion. 
     As described above, the MicroTCA chassis  301  flexibly accommodates both the standard AMC card/modules  306  and the novel AMC+ card/modules  310  of the invention. Advantages of flexibly accommodating both types of cards are described above. 
     It should be understood that the exemplary MicroTCA chassis  301 , as shown in  FIG. 2 , is not limited to being a MicroTCA chassis for hosting standard  306  and non-standard  310  mezzanine card/modules. In other embodiments, the invention contemplates the use of chassis and insertable cards/modules that comply with and/or are compatible with various technical specifications in addition to, or in the alternative to, the AMC Specification. For example the card/modules may be embodied as standard and non-standard sized PC cards, common mezzanine cards, and the like. In other words, the scope of the present disclosure should not be construed as being limited to any particular module or card form factor. 
       FIG. 3  illustrates a perspective view of one exemplary embodiment of an AMC+  310  as shown in  FIG. 2 . In the illustrated example, the AMC+ module  310  is comprised of a modified faceplate  312  coupled to a novel AMC+ printed wiring board (pwb)  330 . The printed wiring board  330  is further comprised of a first portion  332  and a second portion  334 . The first portion  332  represents a conventional single width pwb area as defined in AMC.0 having a width H 1 . The second portion  334  of pwb  330  represents an increased pwb area having a width H 2 . The width H 2  represents an increased single physical dimension which differentiates the novel AMC+ card/module  310  of the invention from the standard AMC card/modules  306  of the prior art. 
     It is noted that the increased area provided by second portion  334  maintains the module depth as specified in AMC.0 while increasing the dimension which governs the width of the AMC module as indicated by the increased width H 2 . It should be appreciated that the novel AMC+ card/module  310 , as modified in its width dimension, maintains full compliance to the AMC.0 specification. 
       FIG. 4   a  illustrates a standard single width AMC card/module  310  comprised of a module printed circuit board (PCB)  440  coupled to a module front plate  442 . The AMC card/module  310  may be inserted into a backplane connector  444  via an AMC connector  446 . Card guides  448  guide the AMC card/module  310  for insertion into the backplane connector  444 . The AMC card/module  310  PCB  440  is shown to have a width dimension, generally designated as H 1 , where H 1 =73.8 mm=2.91 inches. 
       FIG. 4   c  illustrates a conventional double width AMC card/module  312  comprised of the same components described above. However, the double width AMC card/module  312  PCB  464  has a width dimension of H 2 =148.8 mm=5.86 inches. 
       FIG. 4   b  illustrates an AMC+ card/module  306  of the present invention comprised of the same components described above, however, the AMC+ card/module  306  PCB  462  has an increased width dimension of H 2   prime , which is greater than the conventional single width AMC card module  310 , i.e., designated as H 1 , and less than the conventional double width AMC card, designated as (H 1 +H 2 ). Therefore, the width of the PCB  462  of the AMC+ card/module  306 , W AMC+ , is in the range:
 
 H 1 &gt;W   AMC+ &lt;( H 1+ H 2)
 
     Accordingly, the increased width of the AMC+ card/module  310  over a conventional single width AMC card/module  306  is less than H 2 =75 mm, where 
     
       
         
           
             
               
                 
                   
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     By way of example and not limitation, the novel AMC+ card/module  310  shown in  FIG. 4   b  has a total width dimension W AMC+ ,=(H 1 +H 2   prime ) which, in a preferred embodiment, is on the order of about 0.6 inches larger than the width H 1  of the well-known standard single length AMC card module  306 , i.e., (H 2 =0.6). In other preferred embodiments, the AMC+ module  310  is about 0.3 to about 0.6 inches larger than the well-known standard single length AMC card module  306 . It should be understood, however, that in general, the novel AMC+ card/module  310  of the present invention can have any increased width dimension that is greater than the width of a single length AMC card module  306 , i.e., 73.8 mm and less than the width of a double length AMC card module, i.e., 148.8 mm. 
       FIG. 5  representatively illustrates a ATCA card design configured for use with both standard (AMC) and non-standard (AMC+) circuit cards, in accordance with an exemplary embodiment of the present invention. For the purpose of simplicity and clarity, other components of the ATCA card design are not shown in  FIG. 5 . A novel card guide system of the ATCA card  502  includes one or more adjustable card guides  314 , one of which is shown by way of example, to accommodate the insertion of the novel AMC+ card/modules  310  of the invention into a slot of the ATCA card  502 .  FIG. 5  illustrates a single AMC+ card  310  shown in exploded view. The AMC+ card  310  is suitable for insertion into the ATCA slot by utilizing adjustable card guide  314 . 
       FIG. 6  illustrates a number of AMC module configurations suitable for use with the present invention in accordance with the previously described dimensional modifications. The exemplary module configurations suitable for modification in a single dimension include, but are not limited to, single modules of various sizes including a Mid-Size single module  602  and a Full-Size single module  604 . Each of the afore-mentioned module configurations is preferably modified in a single dimension, such as the module&#39;s width “w”. 
     The foregoing is to be construed as only being an illustrative embodiment of this invention. Persons skilled in the art can easily conceive of alternative arrangements providing a functionality similar to this embodiment without any deviation from the fundamental principles or the scope of the invention.