Abstract:
A disclosed apparatus for use with a conduction-cooled card assembly may include a frame comprising first and second thermally conductive portions adapted to engage respective thermal management interfaces on opposite sides of a conduction cooling frame for at least one circuit card. The apparatus may also include a passageway extending between first and second openings in the frame so as to allow cooling fluid to flow into the first opening, through the passageway, and out of the second opening. According to a disclosed method, an insert may be installed between components of a mezzanine connector so as to increase a height of the connector. In some implementations, the installing of the insert may be performed while the first and second components of the mezzanine connector are mounted on a host card and a mezzanine card, respectively, so that installation of the insert between the first and second components increases a spacing between the host card and the mezzanine card.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a Divisional of U.S. application Ser. No. 14/175,377, filed Feb. 7, 2014, which is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    This disclosure relates generally to cooling of circuit boards, and more particularly, to novel apparatuses and techniques that allow circuit boards designed for conduction cooling to be used in a fluid-flow-through cooling environment. 
       BACKGROUND 
       [0003]    Proper thermal management is critical to the successful operation of many types of devices. Standard industry practice for cooling ruggedized avionics modules, for example, is using a conduction cooling frame that is bonded to a printed circuit board to conduct heat out to an external chassis via a standard interface. An example of such a conventional conduction-cooled card assembly  100  is shown in  FIG. 1 . As shown, the assembly  100  includes a primary, or host, card  102  having a multi-electrode electrical connector  104  for establishing a Peripheral Component Interconnect (PCI) bus connection with a motherboard of a chassis (not shown). A secondary, or mezzanine, card  106 , is electrically connected with the primary card  102  via PCI Mezzanine Card (PMC) or switched mezzanine card (XMC) connectors (not shown in  FIG. 1 ) disposed between the cards  102 ,  106 . The primary card  102  and secondary card  106  are both mounted to a conduction cooling frame  108  using screws  110 . Typically, electrical components are mounted on the opposing faces of the cards  102 ,  106 , within the cavity formed between them. As shown, the conduction cooling frame  108  includes thermal management interfaces  112  each having a wedgelock fastener  114  secured to it via screws (not shown). The wedgelock fasteners  114  are used to press the thermal management interfaces  112  against the rails of the chassis so as to allow heat to flow to the chassis through the thermal management interfaces  112 . 
         [0004]    U.S. Pat. No. 7,324,336 (“the &#39;336 patent”) proposed an adaptor frame that can be used to allow a conduction-cooled card assembly to be installed in a certain type of air-flow cooled chassis. With reference to its  FIG. 1 , the &#39;336 patent explains that wedgelock fasteners  42 ,  44  attached to extensions  24   a ,  24   b  of thermally conductive plate  24  can be used to secure an adaptor housing  60  between the extensions  24   a ,  24   b  and rails  34 , thus allowing heat from components on circuit cards  20 ,  22  to be conducted from the plate  24  to the housing  60  and extracted via air flowing through the housing  60 . 
         [0005]    Another known approach for allowing cards of conduction-cooled card assemblies, such as cards  102 ,  106  of assembly  100  shown in  FIG. 1 , to be employed within an air-cooled chassis is to replace the mezzanine connectors on one or both of the cards with taller connectors so as to create a gap that allows air to flow between the cards, and to mount the cards on a different frame that is designed to allow air to flow between the cards from one side of the chassis to the other. 
       SUMMARY 
       [0006]    In some embodiments, an apparatus for use with a conduction-cooled card assembly may include a frame comprising first and second thermally conductive portions adapted to engage respective thermal management interfaces on opposite sides of a conduction cooling frame for at least one circuit card. The apparatus may also include a passageway extending between first and second openings in the frame so as to allow cooling fluid to flow into the first opening, through the passageway, and out of the second opening. The frame may be configured and arranged to be removably installable between opposing interior walls of a chassis and may be further configured and arranged so that the first and second openings can mate with corresponding openings on the opposing interior walls of the chassis when the frame is installed in the chassis. 
         [0007]    In some embodiments, a method may involve acts of: (a) removing a wedgelock fastener from a thermal management interface of a conduction-cooled card assembly; and (b) attaching a frame having a passageway extending therethrough to the thermal management interface so as to allow heat from thermal management interface to be dissipated via fluid flowing through the passageway. 
         [0008]    In some embodiments, a method may comprise an act of installing an insert between components of a mezzanine connector so as to increase a height of the connector. In some implementations, the installing of the insert may be performed while the first and second components of the mezzanine connector are mounted on a host card and a mezzanine card, respectively, so that installation of the insert between the first and second components increases a spacing between the host card and the mezzanine card. 
         [0009]    The foregoing is a non-limiting summary of various embodiments, some of which are defined by the attached claims 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]    The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings: 
           [0011]      FIG. 1  is a perspective view of a conventional conduction-cooled card assembly; 
           [0012]      FIG. 2  is a perspective view of an example of a novel adaptor frame disclosed herein; 
           [0013]      FIG. 3  is a perspective view of an example of a module in which the adaptor frame of  FIG. 2  is mounted on a conduction-cooled card assembly; 
           [0014]      FIG. 4A  is a bottom perspective view of the module shown in  FIG. 3 ; 
           [0015]      FIG. 4B  is a bottom view of the module shown in  FIG. 3 ; 
           [0016]      FIG. 4C  is a first side view of the module shown in  FIG. 3 ; 
           [0017]      FIG. 4D  is a first rear view of the module shown in  FIG. 3 ; 
           [0018]      FIG. 5A  is a top perspective view of the module shown in  FIG. 3 ; 
           [0019]      FIG. 5B  is a top view of the module shown in  FIG. 3 ; 
           [0020]      FIG. 5C  is a second side view of the module shown in  FIG. 3 ; 
           [0021]      FIG. 5D  is a second rear view of the module shown in  FIG. 3 ; 
           [0022]      FIG. 6  is cut-away side view illustrating how cooling fluid may flow through the frame of  FIG. 2  when it is installed within a fluid-flow-through cooled chassis; 
           [0023]      FIG. 7A  is a first perspective view of an example of a novel insert disclosed herein; 
           [0024]      FIG. 7B  is a second perspective view of the insert shown in  FIG. 7A ; 
           [0025]      FIG. 8  is a perspective view illustrating how the insert of  FIG. 8  can be installed between components of a mezzanine connector; 
           [0026]      FIG. 9  is a perspective view illustrating how the assembly of  FIG. 8  can be installed between a host card and a mezzanine card; 
           [0027]      FIG. 10  is a perspective view illustrating how the assembly of  FIG. 9  can be mounted on a frame so as to allow it to be deployed in a fluid-flow-through cooled chassis; 
           [0028]      FIG. 11A  is a first side view illustrating how cooling fluid may flow through the assembly of  FIG. 10  when it is installed within a fluid-flow-through cooled chassis; and 
           [0029]      FIG. 11B  is a second side view of the assembly of  FIG. 10  which excludes the frame of the assembly so as to reveal the internal components of the assembly for illustrative purposes. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Although suitable for some applications, the inventors have recognized certain limitations and disadvantages to the conventional approaches discussed above for allowing conduction-cooled card assemblies or circuit cards from such assemblies to be deployed within an air-cooled chassis environment, and have thus come up with alternative solutions that may provide significant benefits and advantages in at least some circumstances. 
         [0031]    In accordance with some embodiments disclosed herein, an adaptor frame is provided that can be mounted to wedgelock locations on a conduction-cooled card assembly, such as the assembly  100  shown in  FIG. 1 . In some embodiments, for example, the wedgelock fasteners  114  may be removed from the assembly  100  and replaced with an adaptor frame such as that disclosed herein. In some embodiments, the adaptor frame may be attached to the card assembly  100  via fasteners that interface with same mounting points on the thermal management interfaces  112  as did the removed wedgelock fasteners  114 . 
         [0032]    An example embodiment of such an adaptor frame  200  is shown in  FIG. 2 . Various views of a module  302  including the frame  200  mounted on a conduction-cooled card assembly  100  (with the wedgelock fasters  114  removed) are shown in  FIGS. 3-5 . Specifically,  FIG. 3  is a perspective view of an example of a module in which the adaptor frame of  FIG. 2  is mounted on a conduction-cooled card assembly;  FIGS. 4A and 5A  are bottom and top perspective views, respectively, of the module shown in  FIG. 3 ;  FIGS. 4B and 5B  are bottom and top views, respectively, of the module shown in  FIG. 3 ;  FIG. 4C and 5C  are side views of the module shown in  FIG. 3 ; and  FIGS. 4D and 5D  are rear views of the module shown in  FIG. 3 . 
         [0033]      FIG. 6  illustrates how air may flow through the adaptor frame  200  from one side  602  of a chassis  600  to the other side  604  of the chassis  600  in the illustrative embodiment shown. 
         [0034]    As shown in  FIGS. 2, 3, 4A, 4C, 5A, and 5C , the frame  200  may include openings  202  on either side and form a passageway  602  (see  FIG. 6 ) that allows air (e.g., supplied by a blower  614 ) or another suitable cooling fluid to flow from one side to the other through the passageway, as illustrated by the arrows in  FIG. 6 . In some embodiments, the planes occupied by the openings  202  may be oriented substantially orthogonal to the planes in which the cards  102 ,  106  are disposed. Such a configuration may, for example, allow air to flow into the passageway  602  without first having to flow into one of the struts  606 , thus increasing the linearity and efficiency of the air flow. When the frame  200  is installed on a conduction-cooled card assembly  100 , heat from components on the cards  102 ,  106  may flow to the conduction cooling frame  108 , to the thermal management interfaces  112 , and then to the frame  200  where it is dissipated into the air or other fluid flowing through the passageway  602  of the frame  200 . 
         [0035]    Although not illustrated, the frame  200  may include fins or other protrusions within the interior of the passageway  602  so as to increase the surface area of the interior portion of the frame  200  exposed to the fluid flowing through it and thereby increase the amount of heat that may be dissipated via the moving fluid. The frame  200  may be made of any suitable material capable of adequately conducting heat from the thermal management interfaces  112  and allowing the heat so conducted to be dissipated via fluid flowing through the passageway  602 . In some embodiments, for example, the frame  200  may be made of aluminum. The interface between the frame  200  and the thermal management interfaces  112  may be dry, or may alternatively be treated in some way so as to improve the thermal conductivity between the interfacing materials. 
         [0036]    As illustrated best in  FIGS. 4B and 5B , the portions of the frame  200  including the openings  202  may be tapered between a point  204  and a point  206 , with the section at the point  204  being thicker than the section at the point  206 . Because of these tapered portions, the end  212  of the frame  200  that is further away from the motherboard connector  104  is wider than the end  214  of the frame  200  that is closer to a motherboard connector  104  (compare measurements“W 1 ” and “W 2 ” in  FIGS. 4B and 5B , where “W 1 ”&gt;“W 2 ”). 
         [0037]    In some embodiments, these tapered portions of the frame  200  may be formed of an elastomeric material and the openings  202  may include gaskets that create seals with corresponding openings in interior opposing walls  612  of the chassis  600  in which the module  302  is installed. Insertion of a module  302  in a slot between struts  606  of a chassis  600  (as shown in  FIG. 6 ) may, for example, result in the deformation of the elastomeric material and thereby create a force that holds the module  302  in place within the chassis  600 . In some embodiments, the portions of the chassis  600  containing corresponding openings may be additionally or alternatively formed of a suitable elastomeric material and the tapered portions of the frame need not, but may also be, elastomeric. In any event, in some embodiments, once a module  302  is fully inserted in a slot of a chassis  600 , captivated screws  608  (shown in  FIG. 6 ) may be inserted through holes  208  in ear portions  210  of the frame  200  and corresponding holes  610  in a strut  606  of the chassis  600  (the holes  610  for an adjacent slot of the chassis  600  are identified in  FIG. 6 ) to thereby secure the module  302  within the slot. 
         [0038]    In the embodiment shown in  FIGS. 2-6 , the module  302  may be held in place within the chassis, and the gasket seals between the openings  202  and the corresponding openings in the interior walls  612  of the chassis may be maintained, by a vertical force applied against the interior walls  612  of the chassis, e.g., via the elastomeric material on the edge of the frame  200  and/or the chassis interior walls  612 . The use of such a vertical force for such purposes may be contrasted with the technique employed in the embodiment shown in  FIG. 1  of the &#39;336 patent, in which wedgelock fasteners  34  are used to apply horizontal forces between rails  34  so as to hold a plate  24  and cooling adaptor  40  in place within the chassis as well as to maintain seals between each of an inlet  84  and an outlet  86  of the cooling adaptor  40  and a corresponding opening in the side of a rails  34 . Accordingly, in some embodiments, a wedgelock faster  114  need not be employed to secure the module  302  within the chassis and/or to form a suitable gasket seal to allow air flow through the passageway  602 . In alternative embodiments, however, one or more wedgelock fasteners  114  could be additionally or alternatively be employed so as to provide additional or different benefits. 
         [0039]    As noted above, another known approach for allowing cards of conduction-cooled card assemblies, such as cards  102 ,  106  of assembly  100  shown in  FIG. 1 , to be employed within an fluid-flow-through cooled chassis is to replace the mezzanine connectors (e.g., PMC or XMC connectors) on one or both of the cards with taller connectors so as to create a gap that allows air to flow between the cards, and to mount the cards on a different frame that is designed to allow air to flow between the cards from one side of the chassis to the other. Without such a modification, the existing mezzanine connectors, which typically provide only a 10 mm space between the cards, do not provide sufficient room for airflow between the cards for certain applications. 
         [0040]    The inventors have recognized, however, that replacing the mezzanine connectors in such a manner (e.g., by unsoldering the Ball Grid Array (BGA) connections of the mezzanine connectors and soldering new BGA connections for replacement mezzanine connectors in place) can be undesirable, as such a procedure can be expensive, could potentially damage the board, and may lead to the board supplier voiding its manufacturing warranty. 
         [0041]    To overcome such drawbacks, an insert is proposed that may be plugged into an existing mezzanine connector so as to extend the height of the connector to an optimal position to allow flow of air or another suitable fluid between a primary, or host, card  102 , and a secondary, or mezzanine, card  106 , when those cards are mounted on a frame that allows for such fluid flow. In some embodiments, for example, one or more inserts that are approximately 8 mm in length may be employed so as to create a gap of approximately 18 mm between the two cards. Different length inserts can, of course, be used for other applications where more or less fluid flow is desired. In some embodiments, for instance, the insert(s) may alternatively be sized such that the resulting spacing between the cards is 11 mm, 12 mm, 13, mm, 14 mm, 15 mm, 16 mm, 17 mm, 19 mm, 20 mm, or any other suitable distance. 
         [0042]    Two views of an example embodiment of insert  702  are shown in  FIGS. 7A and 7B . As shown, the insert  702  includes pins  704  and holes  706  that may mate with corresponding holes and pins in the mezzanine connector into which it is to be plugged. 
         [0043]      FIG. 8  illustrates how an insert  702  such as that shown in  FIG. 7  may be disposed between respective mating portions  802   a ,  802   b  of a mezzanine connector  802 .  FIG. 9  illustrates how the use of inserts  702  can increase the spacing between a primary card  102  and a secondary card  106 .  FIG. 10  shows an example of how two cards  102 ,  106  having an additional spacing provided by inserts  702  can be mounted on a frame  1002  so as to form a card assembly  1004  that allows fluid to flow from one side of a chassis to another when inserted into an fluid-flow-through cooled chassis.  FIGS. 11A-B  are side views illustrating how cooling fluid (e.g., air supplied by the blower  614 ) may flow through the assembly of  FIG. 10  (in the direction indicated by the arrows) when it is installed within a fluid-flow-through cooled chassis  600 .  FIG. 11A  illustrates the assembly  1004  including the frame  1002 .  FIG. 11B  excludes the frame  1002  so as to reveal the internal components of the assembly  1004  for illustrative purposes. 
         [0044]    As shown if  FIGS. 10 and 11 , the assembly  1004  may have openings  1006  on either side that may mate with corresponding openings in a chassis  600 . As also shown in  FIG. 10 , the frame  1002  may additionally comprise fins  1008  or other protrusions to increase the surface area of the inner part of the frame  1002  that is exposed to the air or other cooling fluid flowing between the cards  102 ,  106 . In some embodiments, the frame  1002  can further be provided with elastomeric, tapered edges and holes to receive captivated screws  608 , generally configured like the corresponding components of the module  302  discussed above in connection with  FIGS. 2-6 , so as to allow the assembly  1004  to be releasably inserted into and maintained in place within the same type of chassis  600  as the module  302  discussed above. In the embodiments shown, heat from components on the circuit cards  102 ,  106  may be dissipated via the fluid flowing through the frame  1002  between the cards  102 ,  106 . 
         [0045]    Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only. 
         [0046]    Various aspects of the present invention may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and is therefore not limited in this application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. 
         [0047]    Also, the invention may be embodied as a method, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments. 
         [0048]    Use of ordinal terms such as “first,” “second,” “third,” etc. in the claims to modify a claim element does not by itself connote any priority, precedence or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claimed element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. 
         [0049]    Also, the phraseology and terminology used herein is used for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.