Enclosure for outside plant equipment with interconnect for mating printed circuit boards, printed circuit board device and method of repairing outside plant equipment
An enclosure for outside plant equipment includes a base unit and first Printed Circuit Board (PCB) carried by the base unit and having a circuit side and opposing component side on which electronic components are mounted. A heat sink is connected to the first PCB at the circuit side and configured to dissipate heat from any electronic components mounted on the first PCB at the component side. A cover is attached to the base unit and has an inside surface covering the enclosure. A second PCB has a circuit side and opposing component side on which electronic components are mounted. The second PCB is supported by the inside surface of the cover. A heat sink is connected to the second circuit board at the circuit side and configured to dissipate heat from any electronic components mounted on the second PCB. A PCB finger connector interconnects the first and second PCB's at the component side.
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This invention relates to enclosures for outside plant equipment, heat sinks used with printed circuit boards for such outside plant equipment, and method of repairing same.
BACKGROUND OF THE INVENTIONElectronics are typically cooled from the top of the component with an interface, for example, a Thermal Interface Material (TIM) located between the top of the component that is secured on a Printed Circuit Board (PCB) and a heat sink, such as a conventional heat sink plate. This type of structure is used in many conventional devices, including many telecommunications Outside Plant (OSP) Equipment enclosures. This type of construction has several drawbacks, especially when used with an OSP Digital Subscriber Line Access Multiplexer (DSLAM) enclosure. If the unit requires testing or trouble-shooting, the PCB must be removed from the enclosure forming the heat sink in order to access electronic components. If the heat sink is removed from the component on the PCB for troubleshooting, there is a possibility of damage to the integrated circuit mounted to the PCB from overheating, because of lack of a heat sink. Some components have very high heat fluxes which require that they be heat sunk at all times, even at room temperature.
Also, some surface mount components do not sit flush on the PCB, due to component float during the solder reflow process. There are also thickness tolerances of each integrated circuit package. This requires the use of thick and soft thermal interface pads, especially when using a common heat sink to cool multiple integrated circuits. For example, extremely compliant and thick thermal interface pads are used between the integrated circuits and the heat sink plate to account for the large tolerance stack up that can be generated. This is accomplished to ensure that the components are always in contact with the thermal pad(s), but not overcompressed/damaged by forces imparted by the heat sink plate to the integrated circuit(s), or to other components that may be located within the thermal pad area. Also, the cost of the thermal interface material is a function of both thermal conductivity and hardness, as well as, sheer volume of the material used. The higher thermal conductivity material is typically more expensive than lower conductivity material. The softer material is typically more expensive than the harder material. Additionally, it is difficult to generate accurate thermal images of components when the heat sink is mounted to the component side of the PCB, and thus, positioned over the component.
There is also an issue with such construction because it is difficult to interconnect PCB's together. The heat sink covers the components on the component side, making interconnection difficult. Thus, an issue arises of how to connect multiple PCB's together in an outside plant equipment enclosure.
SUMMARY OF THE INVENTIONAn enclosure for outside plant equipment includes a base unit and first Printed Circuit Board (PCB) carried by the base unit and having a circuit side and opposing component side on which electronic components are mounted. A heat sink is connected to the first PCB at the circuit side and configured to dissipate heat from any electronic components mounted on the first PCB at the component side. A cover is attached to the base unit and has an inside surface covering the enclosure. A second PCB has a circuit side and opposing component side on which electronic components are mounted. The second PCB is supported by the inside surface of the cover. A heat sink is connected to the second circuit board at the circuit side and configured to dissipate heat from any electronic components mounted on the second PCB. A PCB finger connector interconnects the first and second PCB's at the component side.
In one example, the PCB finger connector is formed as a gold-finger PCB connector. A socket is formed on the component side of each of the first and second PCB's and configured to receive an edge of the PCB finger connector and make a blind-mated connection. The heat sink is connected to the first PCB and mounted within the base unit and secured thereto and the first PCB is secured at the circuit side to the heat sink. The heat sink is connected to the second PCB and mounted to the cover and the second PCB is secured at the circuit side to the heat sink.
In another example, the PCB comprises vias and thick plane sections to transfer heat from electronic components mounted on the component side to the circuit side into the heat sink. The PCB is formed as a plurality of planar configured metallic layers in another example and configured to spread and transfer heat from any electronic components mounted on the component side through the PCB into the heat sink. A Thermal Interface Material (TIM) is applied to the circuit side of each PCB and secured to respective heat sinks. A plurality of TIM strips are connected to each heat sink and respective PCB. Each heat sink comprises riser sections to which the plurality of TIM strips are connected. The TIM strips can be arranged in substantially parallel rows and formed as an adhesive material in an example.
A printed circuit board device is also enclosed in which a first PCB has a circuit side and opposing component side on which electronic components are mounted. A heat sink is connected to the first PCB at the circuit side and configured to dissipate heat from any electronic components mounted on the first PCB at the component side. A second PCB has a circuit side and opposing component side on which electronic components are mounted. A heat sink is connected to the second circuit board and configured to dissipate heat from any electronic components mounted on the second PCB at the component side. A PCB finger connector interconnects the first and second PCB's at the component side.
A method of repairing outside plant equipment is also disclosed.
Other objects, features and advantages of the present invention will become apparent from the detailed description of the invention which follows, when considered in light of the accompanying drawings in which:
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
This type of heat sink device construction shown in
Also, some surface mount components have component float because of the manufacturing tolerances associated with the thickness of the electronic component or other integrated circuit. In the type of arrangement such as shown in
Typically, the electronic components are chosen with a low internal thermal resistance to the PCB for integrated circuit packaging and use large copper areas on the thick planes with the conductive vias 40 to transfer heat from the bottom of the electronic component to the circuit side of the PCB. Because the thermal interface material 36 and heat sink 39 no longer have to be configured to deal with tolerance stack up of the component and the manufacturing processes, the thermal interface material can be thinner than would be necessary otherwise. Additionally, the thinner thermal interface material can be made to have a harder and/or less compliant formulation because the mounting interface tolerance stack up is removed. This also allows direct access to the components for troubleshooting without having to remove the PCB from its heat sink. This also reduces the possibility of damage to an electronic component that might require a heat sink 34. This type of heat sink device 30 as illustrated also allows for thermal imaging of the component side of the PCB since the heat sink no longer blocks the view.
In this particular example, the enclosure 50 could be for an OSP DSLAM such as an OSP LPU or TA1124 or TA1148 as non-limiting examples. These listed enclosures are manufactured by ADTRAN, INC. of Huntsville, Ala.
As noted before, the PCB 32, 58, 80 in each example illustrated in
With this type of construction as described, the TIM can be applied to the circuit side of the PCB and attached to the heat sink located on the circuit side of the PCB. Because the TIM and heat sink no longer have to be configured to deal with tolerance stack up of the component and the manufacturing process, the TIM can be thinner than they would otherwise be, and thus, the TIM as an adhesive or prefabricated TIM strips can be used as illustrated. Additionally, the thinner TIM can be made to have a harder/less compliant formulation because the mounting interface tolerance stack up is removed. This also allows direct access to the components for troubleshooting, without having to remove the PCB from the heat sink. This also reduces the possibility of damage to a component that might require the heat sink. This also permits the thermal imaging of the component side of the PCB since the heat sink no longer blocks the view as illustrated in the various drawings of
The enclosure 50 shown in
When there is a PCB 58 attached to a heat sink 54 in the base unit 52 as illustrated and another PCB 80 attached to the heat sink 78 in the cover 74, a technical problem is how to connect those two boards together in a blind, reliable and inexpensive manner. Typically, simple header and socket combinations have been used in the past, but these are inadequate and not robust enough to work for blind-mate applications. Some connectors had required a large footprint in a “fixed height” connector and are expensive. Other techniques have used cable assembles to connect both halves of a unit together. Cable assemblies are expensive and there is a risk of pinching wires if the cable assembly is not routed correctly when the unit is assembled.
As shown in
A technical solution in accordance with a non-limiting example uses a gold-finger PCB connector 100 to interconnect the first and second PCB's at the component side. These PCB connectors 100 are designed as smaller PCB's with various components 101 to aid in making proper electrical connection with impedances between the PCB's. This PCB finger connector 100 interoperates with scoop type connectors 102 on mating PCB's to allow interconnection between the PCB's as illustrated. This scoop type connector 102 forms a socket on the component side of each of the first and second PCB's as illustrated and is configured to receive an edge of the PCB finger connector and to make a blind-mated connection. The use of the PCB connector 100 and in this example as a gold-finger PCB connector allows for infinite different height combinations between mated boards by changing the length of the PCB connector. This PCB connector 100 has in this example fingertop contacts that are typically gold plated, but other metallic platings could be used. By using the scoop-type connectors 102 as a socket on the PCB, this allows for a large range of misalignment between the boards, but still allows a reliable blind-mated connection. The use of the PCB finger connector also allows for a much broader range of height tolerance between mated PCB halves and the base unit and cover due to the construction with the contact between the connector as a socket and the PCB finger connector. The cost of the combination of the PCB finger connector 100 and socket as a scoop-end connector 102 is typically less than a comparable cable assembly with mating connectors. Additionally, there is no concern about the possibility of pinching a wire or degrading a cable assembly because of temperature considerations.
Also, as illustrated in the example of
This application is related to copending patent application entitled, “OUTSIDE PLANT (OSP) EQUIPMENT, HEAT SINK DEVICE AND METHOD OF REPAIRING OSP EQUIPMENT,” which is filed on the same date and by the same assignee, the disclosure which is hereby incorporated by reference.
Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.
Claims
1. An enclosure for outside plant equipment, comprising:
- a base unit;
- a first printed circuit board (PCB) carried by the base unit and having a circuit side and opposing component side on which electronic components are mounted, and a heat sink connected to the first PCB at the circuit side and configured to dissipate heat from any electronic components mounted on the first PCB at the component side;
- a cover attached to the base unit and having an inside surface covering the enclosure;
- a second PCB having a circuit side and opposing component side on which electronic components are mounted, said second PCB being supported by the inside surface of the cover, and a heat sink connected to said second circuit board at the circuit side and configured to dissipate heat from any electronic components mounted on the second PCB; and
- a PCB finger connector interconnecting the first and second PCB's at the component side.
2. The enclosure according to claim 1, wherein said PCB finger connector comprises a gold-finger PCB connector.
3. The enclosure according to claim 1, and further comprising a socket on the component side of each of the first and second PCB's and configured to receive an edge of the PCB finger connector and to make a blind-mated connection.
4. The enclosure according to claim 1, wherein said heat sink connected to said first PCB is mounted within said base unit and secured thereto and said first PCB is secured at the circuit side to the heat sink.
5. The enclosure according to claim 1, wherein said heat sink connected to said second PCB is mounted to said cover and said second PCB is secured at the circuit side to the heat sink.
6. The enclosure according to claim 1, wherein said PCB further comprises vias and thick plane sections to transfer heat from electronic components mounted on the component side to the circuit side into the heat sink.
7. The enclosure according to claim 1, wherein said PCB comprises a plurality of planar configured metallic layers configured to spread and transfer heat from any electronic components mounted on the component side through the PCB into the heat sink.
8. The enclosure according to claim 1, and further comprising a thermal interface material (TIM) applied to the circuit side of each PCB and secured to the respective heat sink.
9. The enclosure according to claim 8, and further comprising a plurality of TIM strips connected to each heat sink and respective PCB.
10. The enclosure according to claim 9, wherein each heat sink comprises riser sections to which said plurality of TIM strips are connected.
11. The enclosure according to claim 8, wherein said plurality of TIM strips are arranged in substantially parallel rows.
12. The enclosure according to claim 8, wherein each TIM comprises an adhesive material.
13. An enclosure for outside plant equipment, comprising:
- a base unit;
- a first printed circuit board (PCB) supported by the base unit and having a circuit side and opposing component side on which electronic components are mounted;
- a cover attached to the base unit and having an inside surface;
- a second PCB having a circuit side and opposing component side on which electronic components are mounted, said second PCB being supported by the cover at the inside surface, wherein said component sides of said first and second PCB's face each other in opposing relation; and
- a PCB finger connector interconnecting the first and second PCB's at the component side.
14. The enclosure according to claim 13, wherein said PCB finger connector comprises a gold-finger PCB connector.
15. The enclosure according to claim 13, and further comprising a socket on the component side of each of the first and second PCB's and configured to receive an edge of the PCB finger connector and to make a blind-mated connection.
16. The enclosure according to claim 13, and further comprising a heat sink connected to said first PCB and mounted to said base unit and secured thereto and said first PCB is secured at the circuit side to the heat sink.
17. The enclosure according to claim 16, and further comprising a heat sink connected to said second PCB and mounted to said cover and said second PCB is secured at the circuit side to the respective heat sink.
18. The enclosure according to claim 17, and further comprising a thermal interface material (TIM) applied to the circuit side of each PCB and secured to the respective heat sink.
19. The enclosure according to claim 18, and further comprising a plurality of TIM strips connected to each heat sink and respective PCB.
20. The enclosure according to claim 19, wherein each heat sink comprises riser sections to which said plurality of TIM strips are connected.
21. The enclosure according to claim 19, wherein said plurality of TIM strips are arranged in substantially parallel rows.
22. The enclosure according to claim 18, wherein each TIM comprises an adhesive material.
23. The enclosure according to claim 13, wherein each PCB further comprises vias and thick plane sections to transfer heat from electronic components secured on the component side to the circuit side into the heat sink.
24. The enclosure according to claim 13, wherein each PCB comprises a plurality of planar configured metallic layers configured to spread and transfer heat from any electronic components secured on the component side through the PCB into the heat sink.
25. An enclosure for outside plant equipment, comprising:
- a base unit;
- a first PCB carried by the base unit and having a circuit side and opposing component side on which electronic components are mounted, and a first heat sink connected to the first PCB at the circuit side and configured to dissipate heat from any electronic components mounted on the first PCB at the component side;
- a second PCB having a circuit side and opposing component side on which electronic components are mounted, and a second heat sink connected to said second circuit board and configured to dissipate heat from any electronic components mounted on the second PCB at the component side; and
- a PCB finger connector interconnecting the first and second PCB's at the component side.
26. The enclosure according to claim 25, wherein said PCB finger connector comprises a gold-finger PCB connector.
27. The enclosure according to claim 25, and further comprising a socket on the component side of each of the first and second PCB's and configured to receive an edge of the PCB finger connector and to make a blind-mated connection.
28. The enclosure according to claim 25, and further comprising a thermal interface material (TIM) applied to the circuit side of each PCB and secured to the respective heat sink.
29. An enclosure for Outside Plant Equipment, comprising:
- a base unit of the Outside Plant Equipment;
- a cover;
- a first heat sink connected to the base unit;
- a first printed circuit board (PCB) having a circuit side and opposing component side on which components are mounted, said first PCB secured at the circuit side to the first heat sink mounted to the base unit, wherein said first PCB is configured to transfer heat from the bottom of any component on the component side to the circuit side of the first PCB; and
- said cover includes a second heat sink carried by the cover, a second PCB having a circuit side and opposing component side on which components are mounted, said second PCB secured at the circuit side to said second heat sink carried by the cover, wherein electronic components on the component side of either of the PCB's can be readily accessed; and
- a PCB finger connector that interconnects both component sides of the first and second PCB's and securing the cover back onto the base unit.
30. The enclosure according to claim 29, wherein the PCB finger connector comprises a gold-finger PCB connector.
31. The enclosure according to claim 29, wherein the PCB finger connector includes an edge and further comprising a socket on the component side of each of the first and second PCB's to receive an edge and make a blind-mated connection.
32. The enclosure according to claim 29, and further comprising a TIM (Thermal Interface Material) applied to the circuit side of a PCB.
Type: Grant
Filed: Nov 9, 2010
Date of Patent: Apr 2, 2013
Assignee: Adtran, Inc. (Huntsville, AL)
Inventor: Jacob D. McCleary (Harvest, AL)
Primary Examiner: Michail V Datskovskiy
Application Number: 12/942,048
International Classification: H05K 7/20 (20060101);