System and apparatus for efficient heat removal from heat-generating electronic modules

Abstract

This document describes apparatus and methods for a self-contained assembly having an encapsulated electronic module coupled to a heat removal device by a thermally conductive substance. In an illustrative example, the module includes at least one heat dissipating device thermally coupled by internal members to selected portions of a housing. The module housing includes a flat top surface with a perimeter adjoined to side surfaces. In one example, the heat removal device includes a cavity interior surface with an upper surface to match the module top surface, and side walls that match at least 50% by area of the selected portions of the module side surfaces. The cavity interior surface may receive at least 50% of the housing surface area. The matched portion of the cavity side surfaces may be at least 33% by area of the portion of the cavity upper surface that matches the module top surface.

What is claimed is: 
     
       1. An apparatus comprising:
 (a) a first encapsulated electronic module configured as a self-contained assembly and having
 a first generally box-like exterior shape including a generally flat top surface and a perimeter surface comprising side surfaces adjoining the top surface, each side surface having a length along a perimeter of the exterior shape and a height normal (generally perpendicular) to a plane parallel to the top surface; 
 electronic circuitry within the first exterior shape, the electronic circuitry including a plurality of heat dissipating devices; 
 a heat conducting structure internal to the first module adapted to conduct heat from the heat dissipating devices to a selected area of the perimeter surface; and 
 a plurality of module terminals for making electrical connections to the electronic circuitry of the first module; 
 
 (b) a heat removal device comprising a first cavity having an interior surface, the interior surface having
 an upper surface adapted to match a portion of the top surface; 
 side walls adapted to match a portion of the perimeter surface, the matched portion of the perimeter surface comprising at least fifty percent (50%) of the selected area of the perimeter surface; and 
 wherein the interior surface is adapted to receive at least fifty percent (50%) of the first exterior shape, 
 wherein the matched portion of the perimeter surface is at least thirty three percent (33%) of the matched portion of the top surface by area; and 
 
 (c) a thermally conductive substance in the first cavity adapted to thermally couple the upper surface and side walls of the first cavity to the matched portions of the top and perimeter surfaces of the first module. 
 
     
     
       2. The apparatus of  claim 1 , wherein the heat conducting structure comprises a multilayer substrate having at least 4 metallization layers each at least 2.2 mils thick and at least 3 insulation layers. 
     
     
       3. The apparatus of  claim 2 , wherein the multilayer substrate comprises an internal printed circuit board (“PCB”) having a plurality of conductive traces adapted to connect to the heat dissipating devices and to respective ones of the plurality of module terminals, the plurality of conductive traces being formed in a plurality of the metallization layers. 
     
     
       4. The apparatus of  claim 3 , wherein the internal PCB comprises at least 6 conductive layers. 
     
     
       5. The apparatus of  claim 3 , wherein the internal PCB further comprises at least 14 conductive layers. 
     
     
       6. The apparatus of  claim 3 , wherein the plurality of module terminals are arranged along a bottom surface of the first module. 
     
     
       7. The apparatus of  claim 3 , wherein the plurality of module terminals are arranged along one or more overhang surfaces generally parallel to the top surface and adjacent to the perimeter surface of the first module. 
     
     
       8. The apparatus of  claim 3 , further comprising an external PCB external to the first module, the external PCB comprising conductive traces having a module contact region for connecting to respective ones of said module terminals and a system contact region for connecting to respective ones of a plurality of system terminals, the system terminals providing for electrical connection between the first module and circuitry external to the apparatus. 
     
     
       9. The apparatus of  claim 8 , wherein the external PCB lies adjacent to a bottom surface of the first module. 
     
     
       10. The apparatus of  claim 9 , wherein the bottom surface of the first module is generally rectangular and the external PCB lies adjacent and generally parallel to the bottom surface of the first module. 
     
     
       11. The apparatus of  claim 1 , wherein the interior surface of the first cavity is adapted to receive substantially all of the top surface. 
     
     
       12. The apparatus of  claim 1 , wherein the interior surface of the first cavity is adapted to receive substantially all of the perimeter surface. 
     
     
       13. The apparatus of  claim 1 , wherein the heat removal device further comprises a second cavity, and further comprising:
 a second encapsulated electronic module configured as a self-contained assembly and having
 a second generally box-like exterior shape including a generally flat top surface and a perimeter surface comprising side surfaces adjoining the top surface, each side surface having a length along a perimeter of the exterior shape and a height normal (generally perpendicular) to a plane parallel to the flat top surface; 
 electronic circuitry within the second exterior shape, the electronic circuitry including a plurality of heat dissipating devices; 
 a heat conducting structure internal to the second module adapted to conduct heat from the heat dissipating devices to a selected area of the perimeter surface of the second module; and 
 a plurality of module terminals for making electrical connections to the electronic circuitry of the second module, 
 
 wherein the second cavity comprises an interior surface adapted to receive at least fifty percent of the second exterior shape, the interior surface of the second cavity having:
 an upper surface adapted to match a portion of the top surface of the second exterior shape; and 
 side walls adapted to match a portion of the perimeter surface of the second exterior shape, the matched portion of the perimeter surface of the second module comprising at least fifty percent (50%) of the selected area of the perimeter surface of the second module, 
 wherein the matched portion of the perimeter surface of the second module is at least thirty three percent (33%) of the matched portion of the top surface of the second module by area; and 
 
 further comprising a thermally conductive substance in the second cavity adapted to thermally couple the upper surface and side walls of the second cavity to the matched portions of the top and perimeter surfaces of the second module; and 
 an external printed circuit board (“PCB”) external to the first and second modules, the external PCB comprising conductive traces having first and second module contact regions for connecting to respective ones of said plurality of module terminals of the first and second modules and a system contact region for connecting to respective ones of a plurality of system terminals, the system terminals providing for electrical connection between the first and second modules and circuitry external to the apparatus. 
 
     
     
       14. The apparatus of  claim 13 , wherein, for each of the first and second modules, the matched portion of the perimeter surface of the respective module is at least fifty percent (50%) of the matched portion of the top surface of the respective module by area. 
     
     
       15. The apparatus of  claim 13 , wherein, for each of the first and second modules, the matched portion of the perimeter surface of the respective module comprises at least fifty percent (50%) of the entire perimeter surface of the respective module by area. 
     
     
       16. The apparatus of  claim 13 , wherein the plurality of module terminals are arranged along a bottom surface of the first and second modules. 
     
     
       17. The apparatus of  claim 13 , wherein the plurality of module terminals of the first and second modules are arranged along a respective one or more overhang surfaces generally parallel to the top surface and adjacent to the perimeter surface of the respective module. 
     
     
       18. The apparatus of  claim 13 , wherein the first module comprises a first power converter and the second module comprises a second power converter and wherein the first and second modules are connected together to form a power sharing array. 
     
     
       19. The apparatus of  claim 13 , wherein the first module comprises a first power converter, the second module comprises a second power converter, and the first and second modules are connected in cascade with an output of the first power converter connected to an input of the second power converter. 
     
     
       20. The apparatus of  claim 1 , wherein the first module comprises an encapsulating material forming at least some of the top and perimeter surfaces of the exterior shape of the first module. 
     
     
       21. The apparatus of  claim 13 , wherein the first and second modules comprise an encapsulating material forming at least some of their respective top and perimeter surfaces of their respective exterior shapes. 
     
     
       22. The apparatus of  claim 1 , further comprising a bezel having an internal flange adapted to extend into and proximate the side walls of the first cavity;
 an internal shoulder adapted to rest against the heat removal device at places along a perimeter of the first cavity; 
 an outer flange adapted to surround at least a portion of a perimeter edge of an external PCB; and 
 an outer shoulder adapted to rest against a surface of the external PCB. 
 
     
     
       23. The apparatus of  claim 22 , wherein the bezel is adapted to
 provide electrical insulation between the terminals and the side walls of the first cavity; and 
 provide a controlled minimum space between the perimeter surface of the first module and the side walls of the first cavity. 
 
     
     
       24. The apparatus of  claim 22 , wherein:
 the thermally conductive substance comprises a controlled volume of encapsulating material, the controlled volume being set to ensure filling of the first cavity to a predetermined minimum level with the first module assembled in the first cavity; 
 the thermally conductive substance is cured to a solid state, and 
 the thermally conductive substance comprises a minimum level of adhesion between the interior surface of the first cavity and the exterior surface of the first module providing mechanical integrity of the apparatus. 
 
     
     
       25. The apparatus of  claim 13 , further comprising a bezel having
 a first internal flange adapted to extend into and proximate the side walls of the first cavity; 
 a first internal shoulder adapted to rest against a first portion of the heat removal device associated with the first module at places along a perimeter of the first cavity; 
 a second internal flange adapted to extend into and proximate the side walls of the second cavity; 
 a second internal shoulder adapted to rest against a second portion of the heat removal device associated with the second module at places along a perimeter of the second cavity; 
 an outer flange adapted to surround at least a portion of a perimeter edge of the external PCB; and 
 an outer shoulder adapted to rest against a surface of the external PCB. 
 
     
     
       26. The apparatus of  claim 25 , wherein the bezel is adapted to
 provide electrical insulation between the terminals of the first and second modules and the side walls of the first and second cavities; 
 provide a controlled minimum space between the perimeter surfaces of the first and second modules and the side walls of the first and second cavities, respectively. 
 
     
     
       27. The apparatus of  claim 25 , wherein:
 the thermally conductive substance comprises a respective controlled volume of encapsulating material in each of the first and second cavities, the respective controlled volume being set to ensure filling of the first and second cavities to a respective predetermined minimum level with the respective modules assembled in the respective cavities; 
 the thermally conductive substance is cured to a solid state, and 
 the thermally conductive substance comprises a minimum level of adhesion between the interior surfaces of the respective cavities and the respective exterior surfaces of the respective modules providing mechanical integrity to the apparatus. 
 
     
     
       28. A method of making an electronic power component comprising:
 providing heat dissipating electronic circuitry in a first module configured as a stand alone assembly and having module terminals for making electrical connections to the electronic circuitry; 
 providing the first module with a generally box-like exterior shape including a generally flat top surface and a perimeter surface comprising side surfaces adjoining the top surface; 
 providing a heat conducting structure internal to the first module adapted to conduct heat from the heat dissipating devices to a selected area of the perimeter surface; 
 providing a heat removal device for the first module; 
 providing a first cavity in the heat removal device, the first cavity including an interior surface having an upper surface and side walls; 
 adapting the upper surface to match a portion of the top surface of the module; 
 adapting the side walls to match a portion of the perimeter surface comprising at least fifty percent (50%) of the selected area; 
 adapting the interior surface to receive at least fifty percent (50%) of the exterior shape of the first module; 
 configuring the interior surface such that the matched portion of the perimeter surface is at least thirty three percent (33%) of the matched portion of the top surface by area; and 
 providing a thermally conductive substance in the first cavity adapted to thermally couple the upper surface and side walls of the first cavity to the matched portions of the top and perimeter surfaces of the first module. 
 
     
     
       29. The method of  claim 28 , further comprising:
 providing an external printed circuit board (“PCB”) external to the first module; 
 connecting contact regions on the external PCB to respective module terminals of the first module; and 
 providing system terminals for establishing electrical connection between the first module and circuitry external to the apparatus. 
 
     
     
       30. The method of  claim 28 , further comprising:
 providing additional heat dissipating electronic circuitry in a second module configured as a stand alone assembly, the second module having a generally box-like exterior shape including a generally flat top surface and a perimeter surface comprising side surfaces adjoining the top surface; 
 providing a second cavity in the heat removal device including an interior surface adapted to receive at least a portion of the second exterior shape including at least a portion of the top surface, said portion comprising a second top surface area, and at least a portion of the perimeter surface, said portion comprising a second perimeter surface area; 
 providing a thermally conductive substance between said portions of the second top and first perimeter surface areas of the second module and the interior surface of the second cavity; and 
 configuring said second perimeter surface area to be at least 33% of the second top surface area. 
 
     
     
       31. The method of  claim 30 , further comprising providing an external printed circuit board (“PCB”) external to the first and second modules, the external PCB comprising conductive traces having first and second module contact regions for connecting to respective first and second module terminals and a system contact region for connecting to respective system terminals, the system terminals providing for electrical connection between the first and second modules and circuitry external to the apparatus. 
     
     
       32. The method of  claim 31 , further comprising forming a power converter wherein the first module comprises a first power converter and the second module comprises a second power converter and further comprising connecting the modules together to form a power sharing array. 
     
     
       33. The method of  claim 31 , further comprising forming a power converter wherein the first module comprises a first power converter, the second module comprises a second power converter, and further comprising connecting an output of the first power converter to an input of the second power converter. 
     
     
       34. The method of claim 28 in which providing the heat conducting structure internal to the first module comprises providing a multilayer substrate having two or more metallization layers. 
     
     
       35. An apparatus comprising:
 (a) a first electronic module having
 a first exterior shape including a generally flat top surface and a perimeter surface comprising side surfaces adjoining the top surface, each side surface having a length along a perimeter of the first electronic module and a height generally perpendicular to a plane parallel to the top surface; 
 electronic circuitry within the first electronic module, the electronic circuitry including at least one heat dissipating device; 
 a heat conducting structure internal to the first electronic module adapted to conduct heat from the heat dissipating device to a selected area of the perimeter surface; and 
 a plurality of module terminals for making electrical connections to the electronic circuitry; 
   (b) a heat removal device comprising a first cavity having an interior surface, the interior surface having
 an upper surface adapted to match a portion of the top surface; and 
 side walls adapted to match a portion of the perimeter surface, the matched portion of the perimeter surface comprising at least fifty percent (50%) of the selected area of the perimeter surface; and 
 wherein the interior surface is adapted to receive at least fifty percent (50%) of the first exterior shape, 
 wherein the matched portion of the perimeter surface is at least thirty three percent (33%) of the matched portion of the top surface by area; and 
   (c) a thermally conductive substance in the first cavity adapted to thermally couple the upper surface and side walls of the first cavity to the matched portions of the top and perimeter surfaces of the first module.   
     
     
       36. The apparatus of claim 35, wherein the heat conducting structure comprises a multilayer substrate having at least 4 metallization layers each at least 2.2 mils thick and at least 3 insulation layers. 
     
     
       37. The apparatus of claim 36, wherein the multilayer substrate comprises an internal printed circuit board (“PCB”) having a plurality of conductive traces adapted to connect to the heat dissipating devices and to respective ones of the plurality of module terminals, the plurality of conductive traces being formed in a plurality of the metallization layers. 
     
     
       38. The apparatus of claim 37, wherein the plurality of module terminals are arranged along one or more overhang surfaces generally parallel to the top surface and adjacent to the perimeter surface of the first electronic module. 
     
     
       39. The apparatus of claim 37, further comprising an external PCB external to the first electronic module, the external PCB comprising conductive traces having a module contact region for connecting to respective ones of said module terminals and a system contact region for connecting to respective ones of a plurality of system terminals, the system terminals providing for electrical connection between the first electronic module and circuitry external to the apparatus. 
     
     
       40. The apparatus of claim 35, wherein the interior surface of the first cavity is adapted to receive substantially all of the top surface. 
     
     
       41. The apparatus of claim 35, wherein the interior surface of the first cavity is adapted to receive substantially all of the perimeter surface. 
     
     
       42. The apparatus of claim 35, wherein the heat removal device further comprises a second cavity, and further comprising:
 a second electronic module having
 a second exterior shape including a generally flat top surface and a perimeter surface comprising side surfaces adjoining the top surface, each side surface having a length along a perimeter of the second electronic module and a height generally perpendicular to a plane parallel to the flat top surface; 
 electronic circuitry within the second electronic module, the electronic circuitry including at least one heat dissipating device; 
 a heat conducting structure internal to the second electronic module adapted to conduct heat from the heat dissipating device to a selected area of the perimeter surface of the second electronic module; and 
 a plurality of module terminals for making electrical connections to the electronic circuitry of the second electronic module, 
   wherein the second cavity comprises an interior surface adapted to receive at least a portion of an exterior shape of the second electronic module, the interior surface of the second cavity having:
 an upper surface adapted to match a portion of the top surface of the second exterior shape; and 
 side walls adapted to match a portion of the perimeter surface of the second exterior shape, the matched portion of the perimeter surface of the second module comprising at least fifty percent (50%) of the selected area of the perimeter surface of the second module, 
 wherein the matched portion of the perimeter surface of the second module is at least thirty three percent (33%) of the matched portion of the top surface of the second module by area; and 
   further comprising a thermally conductive substance in the second cavity adapted to thermally couple the upper surface and side walls of the second cavity to the matched portions of the top and perimeter surfaces of the second module; and   an external printed circuit board (“PCB”) external to the first and second modules, the external PCB comprising conductive traces having first and second module contact regions for connecting to respective ones of said plurality of module terminals of the first and second modules and a system contact region for connecting to respective ones of a plurality of system terminals, the system terminals providing for electrical connection between the first and second modules and circuitry external to the apparatus.   
     
     
       43. The apparatus of claim 42, wherein, for each of the first and second electronic modules, the matched portion of the perimeter surface of the respective module is at least fifty percent (50%) of the matched portion of the top surface of the respective module by area. 
     
     
       44. The apparatus of claim 42, wherein, for each of the first and second electronic modules, the matched portion of the perimeter surface of the respective module comprises at least fifty percent (50%) of the entire perimeter surface of the respective module by area. 
     
     
       45. The apparatus of claim 42, wherein the first electronic module comprises a first power converter and the second electronic module comprises a second power converter and wherein the first and second electronic modules are connected together to form a power sharing array.