Printed circuit board assemblies

Abstract

A printed circuit board assembly (100) comprising an electronic component (104) that generates heat and a thermal management system (200) comprising the electronic component (104), one or more phase-change modules (108) for distributing and storing heat; a metal frame (110) in thermal contact with the electronic component (104) and having an opening to receive a phase-change module (108); and a heat transfer device (106) in thermal contact with the electronic component (104) and the metal frame (110). The heat transfer device (106) includes a heat diffuser (142) and provides a first heat transfer path during a period of reduced heat dissipation or reduced cooling during which the phase-change module (108) distributes and stores heat. Fig. 2

Description

Title of the invention: Printed circuit board assemblies technical field

[0001] The present invention relates generally to printed circuit board assemblies, and more particularly to printed circuit board assemblies comprising systems and methods for thermal management and management of transient thermal performance problems via the use of integrated phase change modules. Background

[0002] The operation of electronic devices or assemblies requires thermal management and maintenance of electronic components (e.g., integrated circuits, bare printed circuit boards, circuit modules, processors, memory, disk drives, etc.). Electronic components generally generate heat during their operation, or are composed of electronic components that generate heat. As heat accumulates in the electronic device(s), the device or electronic assembly may suffer from overheating, functional failure, degradation, other forms of thermal or mechanical stress, or combinations thereof.

[0003] These thermal constraints can be particularly problematic or impossible to manage for systems requiring (i) multiple electronic components, (ii) maximum processing or computing power, and / or (iii) specialized or harsh operating environments (e.g., aerospace, defense, extreme temperatures, high vibrations, high altitudes, sudden accelerations in high gravity, hypersonic speed, etc.). These systems may suffer from transient thermal performance problems related to temperature fluctuations, intermittent power peaks, and temporary loss of cooling.Examples include (1) exceeding junction temperature limits resulting in significant computational performance degradation (clock signal degradation or derating), (2) matrix temperature spikes / fluctuations, (3) a malfunctioning heat pipe / coolant (e.g., drying out), or a combination thereof. Failure to mitigate or resolve these transient thermal performance issues may make it impossible to maintain electronic components in safe and reliable operating conditions, which can cause or contribute to failures or performance degradation during steady-state or normal system operation.

[0004] It therefore remains necessary to provide alternative or improved printed circuit board assemblies equipped with thermal management systems and processes that can ensure more efficient cooling and / or heat dissipation, while minimizing temperature fluctuations during phase transition and / or mitigating or preventing a decline in thermal performance under normal steady-state operating conditions. Summary

[0005] Certain aspects of the present invention relate to printed circuit board assemblies comprising thermal management systems and methods.

[0006] An aspect given by way of example provides for a thermal management system for a heat source comprising at least one electronic component. The thermal management system comprises one or more phase-change modules comprising a phase-change material for distributing and storing heat; a metal frame in thermal contact with the at least one electronic component and having at least one opening for receiving the one or more phase-change modules; and a heat transfer device in thermal contact with one or more of the electronic component(s) and the metal frame, the heat transfer device providing a first heat transfer path.

[0007] In some embodiments, one or more phase-change modules are configured to distribute and store heat during a period of reduced heat dissipation or reduced cooling.

[0008] In some embodiments, the first heat transfer path is provided during the reduced heat dissipation or reduced cooling period and the first heat transfer path is different from a second heat transfer path during a standard steady-state heat dissipation or cooling period.

[0009] In some embodiments, the heat transfer apparatus includes at least one heat pipe arranged adjacent to the metal frame, such that the one or more phase-change modules incorporated in the metal frame are arranged above, below, on one or more sides of at least one heat pipe, or a combination thereof.

[0010] In some embodiments, the heat transfer device includes at least one heat diffuser which is arranged adjacent to at least one electronic component.

[0011] In some embodiments, the heat transfer apparatus includes an oscillating heat pipe having a first plurality of channels incorporated in at least one heat diffuser and forming a first channel pattern.

[0012] In some embodiments, the oscillating heat pipe further comprises a second plurality of channels forming a second channel pattern, so that the second channel pattern is formed in spaces that are unoccupied by the first channel pattern.

[0013] In some embodiments, the second plurality of channels are configured to receive one or more phase-change modules.

[0014] In some embodiments, the system further includes a metallic layer to contain the one or more phase-change modules in at least one opening of the metallic frame.

[0015] In some embodiments, the metallic layer comprises copper and is disposed on at least one opening of the metallic frame by welding, brazing, soldering or thermal epoxy.

[0016] In some embodiments, at least one opening in the metal frame includes a pocket.

[0017] In some embodiments, at least one opening in the metal frame includes a T-shaped pocket, the T-shaped pocket having a pair of rims for receiving the metal layer.

[0018] In some embodiments, the metal frame comprises aluminum, copper, or alloys thereof.

[0019] In some embodiments, the reduced heat dissipation period or reduced cooling is due to operating conditions including high altitude, high acceleration, hypersonic speed, intermittent peaks in computing power usage, or a combination thereof.

[0020] Another aspect given by way of example provides for a printed circuit board assembly. The printed circuit board assembly comprises a bare printed circuit board having at least one electronic component that generates heat; one or more phase-change modules comprising phase-change materials for distributing and storing heat; a metal frame coupled to the bare printed circuit board and in thermal contact with the at least one electronic component, the metal frame further having at least one opening for receiving the one or more phase-change modules; and a heat transfer device in thermal contact with one or more of the electronic component(s) and the metal frame, the heat transfer device providing a first heat transfer path.

[0021] In some embodiments, one or more phase-change modules are configured to distribute and store heat during a period of reduced heat dissipation or reduced cooling.

[0022] In some embodiments, the first heat transfer path is provided during the reduced heat dissipation or reduced cooling period and the first heat transfer path is different from a second heat transfer path during a standard steady-state heat dissipation or cooling period.

[0023] In some embodiments, the heat transfer apparatus includes at least one heat pipe arranged adjacent to the metal frame, such that the one or more phase-change modules incorporated in the metal frame are arranged above, below, on one or more sides of at least one heat pipe, or a combination thereof.

[0024] In some embodiments, the heat transfer device includes at least one heat diffuser which is arranged adjacent to at least one electronic component.

[0025] In some embodiments, the heat transfer apparatus includes an oscillating heat pipe having a first plurality of channels incorporated in at least one heat diffuser and forming a first channel pattern.

[0026] In some embodiments, the oscillating heat pipe further comprises a second plurality of channels forming a second channel pattern, so that the second channel pattern is formed in the spaces that are unoccupied by the first channel pattern.

[0027] In some embodiments, the second plurality of channels are configured to receive one or more phase-change modules.

[0028] In some embodiments, the printed circuit board assembly further includes a metallic layer to contain one or more phase-change modules in at least one opening of the metallic frame.

[0029] In some embodiments, the metallic layer comprises copper and is disposed on one or more of the opening(s) of the metallic frame by welding, brazing, soldering or thermal epoxy.

[0030] In some embodiments, at least one opening in the metal frame includes a pocket.

[0031] In some embodiments, at least one opening in the metal frame includes a T-shaped pocket, the T-shaped pocket having a pair of rims for receiving the metal layer.

[0032] In some embodiments, the metal frame comprises aluminum, copper or alloys thereof.

[0033] In certain embodiments, the reduced heat dissipation or cooling period is due to operating conditions including a high altitude, high acceleration, hypersonic speed, intermittent computing power, or a combination thereof.

[0034] Another aspect given by way of example provides a method for manufacturing a printed circuit board assembly comprising at least one electronic component that generates heat. The method comprises the steps of (a) forming at least one opening in a metal frame to receive the at least one electronic component; (b) forming at least one opening in the metal frame to receive one or more phase-change modules, the one or more phase-change modules comprising a phase-change material for distributing and storing heat; (c) filling the at least one opening with the one or more phase-change modules; and (d) fixing a metallic layer over the at least one opening to contain the one or more phase-change modules within the at least one opening of the metal frame.

[0035] In some embodiments, the method further includes a step of forming at least one groove in the metal frame to make contact with a surface of a heat transfer device, so that the heat transfer device is in thermal contact with one or more of the electronic component(s) and the metal frame, the heat transfer device further providing a first heat transfer path.

[0036] In some embodiments, the heat transfer apparatus includes at least one heat pipe, the at least one heat pipe being disposed at least partially inside the groove, so that the one or more phase-change modules incorporated in the metal frame are disposed above, below, on one or more sides of the at least one heat pipe, or a combination thereof.

[0037] In some embodiments, at least one opening in the metal frame includes a T-shaped pocket, the T-shaped pocket having a pair of rims for receiving the metal layer.

[0038] In some embodiments, one or more phase-change modules are configured to distribute and store heat during a period of reduced heat dissipation or reduced cooling.

[0039] In some embodiments, the first heat transfer path is provided during the reduced heat dissipation or reduced cooling period and the first heat transfer path is different from a second heat transfer path during a standard steady-state heat dissipation or cooling period. Brief description of the drawings

[0040] The invention is best understood from the following detailed description when read in conjunction with the accompanying drawings, where analogous features have the same reference numbers. Where a plurality of similar features are present, a single reference number may be assigned to the plurality of similar features, with a lowercase designation referring to specific features. When referring to the features collectively or to one or more nonspecific features, the lowercase designation may be omitted. Furthermore, in accordance with common practice, the various features of the drawings are not drawn to scale unless otherwise indicated, and the dimensions of the various features may be enlarged or reduced for clarity. The drawings include the following figures:

[0041] [Fig. 1] The [Fig. 1] represents an assembly of printed circuit boards given as an example.

[0042] [Fig.2] Fig.2 is an exploded view of the printed circuit board assembly shown in Fig.1

[0043] [Fig.3] The [Fig.3] represents a part of the printed circuit board assembly shown in the [Fig.1].

[0044] [Fig.4A] Figures 4A-4B-4C-4D illustrate the stages formed from an example of a manufacturing process for the part of the printed circuit board assembly shown in [Fig.3].

[0045] [Fig.4B] Figures 4A-4B-4C-4D illustrate the stages formed from an example of a manufacturing process for the part of the printed circuit board assembly shown in [Fig.3].

[0046] [Fig.4C] Figures 4A-4B-4C-4D illustrate the stages formed from an example of a manufacturing process for the part of the printed circuit board assembly shown in [Fig.3].

[0047] [Fig.4D] Figures 4A-4B-4C-4D illustrate the stages formed from an example of a manufacturing process for the part of the printed circuit board assembly shown in [Fig.3].

[0048] [Fig.5] The [Fig.5] is a flowchart showing the process steps used in stages represented in [Fig.4A] to 4D.

[0049] [Fig.6A] Fig.6A represents an example of a thermal management system, showing a heat transfer device given as an example providing a heat transfer path during a period of reduced heat dissipation or reduced cooling.

[0050] [Fig.6B] The [Fig.6B] represents the thermal management system shown in the [Fig.6A], showing another heat transfer path during a period of heat dissipation or cooling in standard steady state.

[0051] [Fig.7A] Figures 7A-7B represent another embodiment of a heat transfer device given by way of example.

[0052] [Fig.7B] Figures 7A-7B represent another embodiment of a heat transfer device given by way of example.

[0053] [Fig.8] Fig.8 represents another embodiment of a heat transfer device given by way of example. Detailed description

[0054] The thermal management systems disclosed herein can be used for electronic components associated with printed circuit board assemblies (PCBs), including PCBs used in specialized or harsh operating environments (e.g., aerospace, defense, extreme temperatures, high vibrations, high altitudes, sudden acceleration in high gravity, hypersonic speed, etc.). Although the thermal management systems described herein relate to electronic components associated with PCBs, it shall be understood that the invention is not limited to this. Rather, aspects of the present invention are applicable in applications or products in which it is desirable to manage or stabilize the thermal energy (heat or temperature) of electronic components.

[0055] As used in this document, the term "printed circuit board assembly" includes electronic components or other electronic units that generate heat (to varying degrees) or require heat dissipation or cooling. In one exemplary embodiment, a printed circuit board assembly may include semiconductor products, such as field-programmable gate arrays (FPGAs), central processing units (CPUs), and graphics processing units (GPUs). In another exemplary embodiment, a printed circuit board assembly may include a bare printed circuit board having high-power semiconductor products, processors, or other electrical components, the bare printed circuit board being coupled to a thermal frame.The term "thermal frame" may include any electronic enclosure, unit, box, frame, mount, compartment adapted to house, contain or enclose (partially or totally; in a fixed or removable manner) bare printed circuit boards and / or electronic components.

[0056] With reference to the drawings, [Fig. 1] and [Fig. 2] illustrate an example printed circuit board assembly, such as a printed circuit board assembly 100. In general, the printed circuit board assembly 100 comprises at least an electronic component 104, a heat transfer device 106, and one or more phase-change modules 108. In an embodiment given by way of example, the printed circuit board assembly 100 comprises a bare printed circuit board 102 having at least one heat-generating component, such as the electronic component 104. Coupled to the bare printed circuit board 102, a metal frame 110 is positioned within the printed circuit board assembly 100, such that the metal frame 110 is in thermal contact with the electronic component 104. For this purpose, the metal frame 110 may have a size, shape, and / or surface contours configured to match one or more components of the printed circuit board assembly 100, such as the heat transfer device 106 and the electronic component 104.In addition, the metal frame 110 may include a metal having satisfactory heat or thermal conductivity, such as aluminium, copper or alloys thereof (e.g. aluminium or copper alloys).

[0057] The metal frame 110 further includes at least one opening 112 (for example, a pocket) for receiving one or more phase-change modules 108. The phase-change modules 108 comprise a phase-change material for distributing and storing heat generated by the electronic component 104. In one embodiment given by way of example, phase-change modules 108 are configured to distribute and store heat during a period of reduced heat dissipation or reduced cooling. This period of reduced heat dissipation or reduced cooling may be due to operating conditions such as high altitude, high acceleration, hypersonic speed, intermittent computing power, or a combination thereof.

[0058] To facilitate and / or manage the distribution and / or storage of heat from the electronic component 104, the printed circuit board assembly 100 includes the heat transfer device 106. In one embodiment given by way of example, the heat transfer device 106 consists of at least one heat pipe 118 ([Fig. 2]). The heat pipe 118 is positioned relative to the electronic component 104 and the metal frame 110 such that the heat pipe 118 is in thermal contact with one or more of the electronic components 104 and the metal frame 110. In this configuration, the heat pipe 118 provides a heat transfer path 114 for the heat generated by the electronic component 104. In one embodiment given by way of example, the heat transfer path 114 is provided during the period of reduced heat dissipation or reduced cooling.Furthermore, the heat transfer path 114 may be different from another. path 116 of heat transfer during a period of heat dissipation or cooling in standard / normal steady state.

[0059] In another embodiment given by way of example, the heat transfer device 106 consists of at least one heat diffuser 142, such as a metal plate (for example, made of copper or a copper alloy) ([Fig. 2]). The heat diffuser 142 is positioned relative to the electronic component 104 and the metal frame 110, such that the heat diffuser 142 is in thermal contact with one or more electronic components 104 and the metal frame 110. In this configuration, the heat diffuser 142 provides a heat transfer path 144 for the heat generated by the CCA or its components, such as the electronic component 104. In one embodiment given by way of example, the heat transfer path 144 is provided during the period of reduced heat dissipation or reduced cooling.Furthermore, heat transfer path 144 may differ from another heat transfer path during a standard / normal steady-state heat dissipation or cooling period, such as heat transfer path 116.

[0060] In yet another embodiment given by way of example, the heat diffuser 142 additionally or optionally comprises an oscillating heat pipe 136 ([Fig. 8]) incorporated therein. At least one oscillating heat pipe 136 is positioned relative to one or more of the electronic component 104 and the metal frame 110, such that the oscillating heat pipe 136 is in thermal contact with one or more of the electronic component 104 and the metal frame 110. In this configuration, the oscillating heat pipe 136 provides a heat transfer path, such as the heat transfer path 144, for the heat generated by the electronic component 104. In one embodiment given by way of example, the heat transfer path 144 is provided during the reduced heat dissipation or reduced cooling period.Furthermore, heat transfer path 144 may differ from another heat transfer path during a standard / normal steady-state heat dissipation or cooling period, such as heat transfer path 116.

[0061] Referring now to [Fig. 2] and [Fig. 3], an example heat pipe 118 is arranged adjacent to the metal frame 110, so that the phase-change modules 108 incorporated into the metal frame 110 can be arranged above (as shown by arrow 140a in [Fig. 3]), below (as shown by arrow 140b in [Fig. 3]), or on one or more sides (as shown by arrow 140c) of the heat pipe 118. Desirably, at least one opening or pocket 112 of the metal frame 110 can be defined within the metal frame 110. The opening or pocket 112 is configured to receive a module respective phase change 108, so that the opening or pocket 112 has a size and shape sufficient to receive a respective phase change module 108.

[0062] Furthermore, in this configuration, the phase-change modules 108 can be in thermal contact with the electronic component 104 because, as illustrated in [Fig. 3], the phase-change modules 108 incorporated in the metal frame 110 can be arranged above (as shown by arrow 140a in [Fig. 3]), below (as shown by arrow 140b in [Fig. 3]) and / or on one or more sides (as shown by arrow 140c in [Fig. 3]) of at least one pocket 124. The at least one pocket 124 of the metal frame 110 is configured to receive respectively a component of the printed circuit board assembly 100 that generates heat, such as the electronic component 104.

[0063] Desirably, incorporating the phase-change modules 108 within a portion of the metal frame 110 such that the phase-change modules 108 are in thermal contact with one or more of the metal frame 110 and the electronic component 104, as described above, allows for better management of transient thermal performance issues (as will be discussed below). Furthermore, incorporating a phase-change material such as that used in the phase-change modules 108 within a portion of the metal frame 110 does not interfere with the operation of the heat pipe 118 (which provides the heat transfer path 116) under normal steady-state conditions.

[0064] With regard to [Fig. 4A] to 4D and 5, an example of a method for manufacturing a portion of the printed circuit board assembly 100, such as method 500, is disclosed. The details of method 500 set forth below relate to the elements of the printed circuit board assembly 100 given by way of example. In particular, method 500 includes steps for incorporating the phase-change modules 108 within the metal frame 110, as described above.

[0065] More specifically, as illustrated in [Fig. 4A] to [Fig. 4D] and the flowchart in [Fig. 5], the method 500 includes a step 510 of forming at least one opening in a metal frame, such as an opening or pocket 124 in the metal frame 110, to receive the electronic component 104. In addition, in an embodiment given by way of example, the method 500 also includes a step of forming at least one groove 126 ([Fig. 4A]) in the metal frame 110 to make contact with a surface of a heat transfer device, such as the heat transfer device 106.

[0066] The groove 126 is formed so that the heat transfer device 106, including the heat pipe 118, is in thermal contact with the electronic components 104 and / or the metal frame 110. More specifically, the groove 126 is formed so that the heat pipe 118 is disposed at least partially inside the groove 126. In this configuration, the heat transfer device 106, including the heat pipe 118, provides a first heat transfer path, such as path 114. In one embodiment given by way of example, path 114 is used during a period of reduced heat dissipation or reduced cooling. In addition, or optionally, the first heat transfer path 114 is different from a second heat transfer path, such as path 116 (as shown in [Fig. 6B]), which is provided during a period of standard / normal steady-state heat dissipation or cooling.

[0067] During steady-state operation, the heat transfer path, such as path 116, provides a path with a higher overall thermal conductivity through the heat pipe 118, compared to other components of the printed circuit board assembly 100, for example. In general, heat pipes are two-phase heat transfer devices that utilize the evaporation and condensation of the working fluid to overcome any semiconductor / metal thermal conductivity. For example, heat pipes can typically achieve a higher thermal conductivity than copper. Consequently, the heat pipe 118, through which path 116 is supplied, behaves essentially as a thermal superconductor, so that negligible heat is transferred along the other thermal paths. Thus, the heat pipe 118 is the dominant / primary heat transfer path during normal steady-state operation.

[0068] However, during a period of reduced cooling or heat dissipation, the heat pipe 118 may become less efficient due to condensation loss or drying, for example. In one embodiment given by way of example, this period of reduced heat dissipation or reduced cooling may be due to operating conditions such as high altitude, high gravitational force (G-force), high acceleration, hypersonic speed, intermittent peaks in computing power utilization, or a combination thereof. During this period of reduced heat dissipation or reduced cooling, the temperature begins to rise, and the heat pipe 118, through which path 116 is supplied, becomes less efficient.Thus, in such an embodiment, the heat pipe 118 becomes a secondary heat transfer path (i.e., it is no longer the dominant or primary heat transfer path). Consequently, a heat or thermal transfer path other than path 116, such as heat transfer path 114, becomes the dominant or primary heat transfer path. It is desirable that the phase-change modules 108 be located along heat transfer path 114 in order to distribute and / or store heat. Thus, path 114 becomes the path. of dominant or primary heat transfer to predetermined melting points when the phase-change modules 108 begin to absorb heat, while maintaining their temperature constant for a certain period of time. In this way, temperature fluctuations during phase transitions are minimized and / or drops in thermal performance during steady-state conditions are mitigated or prevented, so that the printed circuit board assemblies 100 comprising the electronic component 104 can be maintained in a reliable operating state.

[0069] As illustrated in [Fig. 4B] and the flowchart in [Fig. 5], the method 500 also includes a step 520 of forming at least one opening 112 in the metal frame 110 to receive the phase-change modules 108. In an exemplary embodiment of the printed circuit board assembly 100, the opening 112 in the metal frame 110 includes a T-shaped pocket. The opening 112 may include a pair of flanges 128 for receiving a portion of the metal layer 130.

[0070] As stated above, the phase change modules 108 include a phase change material for distributing and storing heat from the electronic component 104. In one embodiment given by way of example, the phase change modules 108 are configured to distribute and store heat away from at least the electronic component 104 during the period of reduced heat dissipation or reduced cooling.

[0071] As illustrated in [Fig.4C] and the flowchart in [Fig.5], the process 500 further includes a step 530 consisting of filling the opening or pocket 112 with the phase change modules 108. The pocket 112 is filled with the phase change modules 108, so that the phase change modules 108 incorporated in the metal frame 110 are arranged above (as shown by arrow 140a in [Fig.3]), below (as shown by arrow 140b in [Fig.3]) and / or on one or more sides (as shown by arrow 140c in [Fig.3]) of the heat pipe 118.

[0072] As shown in [Fig. 4D] and the flowchart in [Fig. 5], the method 500 also includes a step 540 of attaching the metal layer 130 to the pocket 112 to contain the phase-change modules 108 inside the pocket 112 of the metal frame 110. More specifically, the metal layer 130 can act as a lid or covering element configured to engage with the edges 128 of the pocket 112 ([Fig. 4B]). Furthermore, in one embodiment given by way of example, the metal layer 130 can comprise copper and can be disposed on the pocket 112 of the metal frame 110 by welding, brazing, soldering, or thermal epoxy.

[0073] Referring now to [Fig. 6A] and [6B], when the printed circuit board assembly 100 is heated or subjected to other forms of thermal stress, the printed circuit board assembly 100 may require thermal performance management to remain within operating parameters / specifications. In one exemplary embodiment, a thermal management system 200, including phase-change modules 108 integrated into the metal frame 110 and / or the heat transfer device 106, serves to perform this management function. The thermal management system 200 is discussed further with reference to the components of the printed circuit board assembly 100.

[0074] In one embodiment given by way of example, the thermal management system 200 is configured to manage a heat source comprising at least one electronic component, such as the electronic component 104. The thermal management system 200 includes phase-change modules, such as the phase-change modules 108 discussed above. The phase-change modules 108 include a phase-change material for distributing and / or storing heat from the electronic component 104. A metal frame, such as the metal frame 110, is in thermal contact with the electronic component 104. The metal frame 110 has at least one opening, such as the pocket 112, for receiving phase-change modules 108. A heat transfer device, such as the heat transfer device 106, is also in thermal contact with the electronic component 104 and / or the metal frame 110.The heat transfer unit 106 is configured to provide a first heat transfer path. Further details on the individual components of the thermal management system 200 and their operation are discussed below.

[0075] The metal frame 110 may comprise a metal having satisfactory heat or thermal conductivity, such as aluminum, copper, or alloys thereof (for example, aluminum or copper alloys). In one embodiment given by way of example, the opening 112 of the metal frame 110 may comprise a pocket, such as a T-shaped pocket having a pair of flanges 128 (as shown in [Fig. 4B]) for receiving a cover or covering element, such as a metal layer 130. The metal layer 130 may comprise a metal, such as copper, and may be disposed on at least one opening 112 by welding, brazing, soldering, or thermal epoxy.

[0076] The phase-change modules 108 are configured to distribute and / or store heat during a period of reduced heat dissipation or reduced cooling. This period of reduced heat dissipation or reduced cooling may occur due to or in connection with conditions operating conditions include high altitude, high acceleration, hypersonic speed, intermittent computing power, or a combination thereof. Such operating conditions can lead to transient thermal problems that require heat management from the electronic component 104 via the thermal management system 200.

[0077] To achieve this, the thermal management system 200 includes a heat pipe 118. The heat pipe 118 is arranged adjacent to the metal frame 110, so that the phase change modules 108 incorporated in the metal frame 110 are arranged above (as shown by arrow 140a in [Fig.3]), below (as shown by arrow 140b in [Fig.3]) and / or on one or more sides (as shown by arrow 140c in [Fig.3]) of the heat pipe 118. In one embodiment given by way of example, the heat pipe 118 is configured to provide a first heat transfer path 114 during the period of reduced heat dissipation or reduced cooling ([Fig.0A]).Furthermore, the first heat transfer path 114 may differ from a second heat transfer path 116, which is provided by the heat transfer device 106 during a standard steady-state heat dissipation or cooling period ([Fig. 6B]). The details of the first heat transfer path 114 and the second heat transfer path 116 are now discussed below.

[0078] As shown in [Fig. 0A], the printed circuit board assembly 100 includes an electronic component 104. The electronic component 104 generates heat, thus requiring thermal management to reduce or eliminate the risk of functional failure and / or other undesirable effects of thermal stress. The cooling or dissipation of this heat from the electronic component 104 during the reduced heat dissipation or reduced cooling period is indicated by the first heat transfer path 114. As explained above, the cooling or heat dissipation of the electronic component 104 is provided by the path 114 because the heat pipe 118 offers a higher overall thermal conductivity compared to the other components of the printed circuit board assembly 100.This path 114 is indirectly or directly determined by at least the position and configuration of the phase change modules 108 relative to one or more of the metal frame 110, the electronic component 104 and the heat transfer device 106. In the embodiment given by way of example shown in [Fig. A], the heat from the electronic component 104 is distributed and / or stored (via the path 114) through the heat pipe 118 and through the metal frame 110 in which phase change modules 108 are incorporated.

[0079] In contrast, as illustrated in [Fig. 6B], the cooling or heat dissipation of the electronic component 104 during the standard / normal steady-state heat dissipation or cooling period is indicated by the second heat transfer path 116. The second heat transfer path 116 differs from the first heat transfer path 114, at least in that the heat transfer path 116 indicates that heat from the electronic component 104 is distributed / dissipated or stored through the heat pipe 118 under standard / normal steady-state conditions. Thus, the heat transfer path 114 involving the use of the phase-change modules 108 replaces the heat transfer path 116 along the heat pipe 118 as the primary or dominant heat transfer path during the reduced heat dissipation or reduced cooling period.In this way, the inclusion of the phase-change modules 108 in the thermal management system 200 of the printed circuit board assembly 100 has a neutral effect on heat dissipation or cooling under normal / standard steady-state conditions, or at least does not negatively affect it. Thus, the first heat transfer path 114 provides an additional benefit to the thermal management of the printed circuit board assembly 100. Furthermore, the thermal management system 200, comprising the first heat transfer path 114 and the second heat transfer path 116, ensures more efficient cooling and / or heat dissipation because path 114 is configured to minimize temperature fluctuations during the phase transition, and path 116 is configured to mitigate or prevent the drop in thermal performance under normal steady-state operating conditions.

[0080] Referring now to [Fig. 7A] and [Fig. 7B], another embodiment given by way of example of a thermal management system 200 further or optionally includes a heat diffuser 142 and phase-change modules 108 incorporated therein. The heat diffuser 142 is positioned relative to the electronic component 104 (as shown in [Fig. 6A] and [Fig. 6B]) and the metal frame 110, such that the heat diffuser 142 is in thermal contact with the electronic component 104 and / or the metal frame 110. In this configuration, the heat diffuser 142 provides a heat transfer path 144 for the heat generated by the electronic component 104. In one embodiment given by way of example, the heat transfer path 144 is provided during the period of reduced heat dissipation or reduced cooling ([Fig. 6A]).Furthermore, the heat transfer path 144 may be different from another heat transfer path during a standard / normal steady-state heat dissipation or cooling period, such as the heat transfer path 116 ([Fig.6B]).

[0081] In an embodiment given by way of example, as illustrated in [Fig. 7B], the heat diffuser 142 is configured to distribute heat from a local heat source. The local heat source may include the electronic component 104. The electronic component 104 may be arranged adjacent to the heat diffuser 142, such that the heat from the electronic component 104 is supplied to a region 152 located in the center of the heat diffuser 142. In this way, the heat diffuser 142 distributes the heat from the central region 152 and throughout an area defined by the heat diffuser 142. The heat distribution rate may be affected by a heat sink surface (having a predetermined heat transfer coefficient) arranged on the opposite side of the heat diffuser 142.

[0082] The heat distribution rate decreases as the distance from the local heat source increases, due to the increase in thermal resistance. In one exemplary embodiment, the heat diffuser 142 has a square geometry (as shown in [Fig. 7B]), such that the four corners 150 are located at the furthest distance from the central region 152. Thus, the heat distribution rate is lowest at the four corners 150, meaning that a heat transfer path through one or more of the four corners 150 is overall a less efficient region / heat transfer path (and therefore has a lower temperature) of the heat diffuser 142. It should be understood, however, that the heat diffuser 142 is not limited to a square geometry.The heat diffuser 142 may have at least one location along an outer periphery that represents the distance(s) farthest from the region 152 located at the center of the heat diffuser 142. In another embodiment given by way of example, the heat diffuser 142 may have a rectangular or circular geometry, and the phase-change modules 108 may be encapsulated (as shown in [Fig. 7A]) along an outer periphery of the heat diffuser 142 (for example, along a peripheral edge of a circular heat diffuser 142). Those skilled in the art will understand from the description in this document that other geometries (regular or irregular) of the heat diffuser 142 may depend on the design of the printed circuit board assembly 100 or its components (for example, the electronic component 104).

[0083] In the exemplary embodiment shown in [Fig. 7A], the phase-change module 108 can be encapsulated in at least one of the four corners 150, where openings or pockets 156 are formed. In one exemplary embodiment, the metallic layer 130 can be arranged over the pockets 156 to contain the phase-change modules 108 inside the pockets. 156. More specifically, the metal layer 130 can act as a lid or covering element. Furthermore, in one embodiment given by way of example, the metal layer 130 can comprise copper and can be disposed on the pockets 156 by welding, brazing, soldering, or thermal epoxy. The integration of the phase-change modules 108 in at least one of the four corners 150 does not negatively affect the thermal performance of at least one heat diffuser 142 under steady-state operating conditions, or at least has a neutral effect on it. Indeed, as indicated above, the heat diffuser 142 is less efficient in terms of heat distribution rate at locations furthest from the local heat source (center).

[0084] During a period of reduced cooling and / or heat dissipation, the heat diffuser 142 becomes less efficient (i.e., due to operating conditions such as high altitude, high gravitational force (G-force), high acceleration, hypersonic speed, intermittent peaks in computing power usage, or a combination thereof), and the temperature begins to rise. Thus, another heat or thermal transfer path, different from the heat transfer path through the region 152 located at the center of the heat diffuser 142, becomes the primary or dominant heat transfer path, for example, the heat path 144 ([Fig. 6A]). Phase-change modules 108 are located along this path 144.The phase change modules 108 encapsulated inside the heat diffuser 142 begin to absorb heat while maintaining a constant temperature for a certain period of time. In this way, temperature fluctuations during the phase transition are minimized. In addition, or optionally, the decrease in thermal performance under steady-state conditions is mitigated or prevented because the phase change modules 108 are integrated in the location(s) furthest from the local heat source (center) and are therefore less efficient at dissipating or distributing heat under steady-state conditions.

[0085] Figure 8 shows another embodiment given by way of example of a thermal management system 200, in which an oscillating heat pipe, such as the heat pipe 136, is incorporated into the heat diffuser 142. As shown in Figure 8, the oscillating heat pipe 136 comprises a first plurality of channels 132 forming a first channel pattern, for example, a serpentine channel pattern. The oscillating heat pipe 136 further comprises a second plurality of channels 134 forming a second channel pattern, for example, a serpentine channel pattern, such that the second channel pattern is formed in the spaces of the oscillating heat pipe 136 that are unoccupied by the first channel pattern formed by the first plurality of channels 132. The material of the phase-change modules 108 is configured to be distributed via the second plurality of channels 134 of the oscillating heat pipe 136. This distribution can be activated during periods of reduced heat dissipation or reduced cooling. In this configuration, the second plurality of channels 134 containing a phase-change material such as that used in phase-change modules 108 does not interfere with the first plurality of channels 132 containing the working fluid for heat dissipation and / or cooling under normal steady-state conditions. Thus, the integration of the phase-change material into the oscillating heat pipe 136 and / or the heat diffuser 142 does not undesirably affect heat dissipation and / or cooling under normal steady-state conditions, or at least has a neutral effect on it.

[0086] Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. On the contrary, various modifications may be made to the details within the scope and range of equivalents of the claims and without departing from the invention.

Claims

Demands

1. Thermal management system (200) for a heat source comprising at least one electronic component (104), the thermal management system (200) comprising: one or more phase change modules (108) comprising a phase change material for distributing and storing heat; a metal frame (110) in thermal contact with the at least one electronic component (104) and having at least one opening for receiving the one or more phase change modules (108);and a heat transfer device (106) in thermal contact with one or more of the electronic component(s) (104) and the metal frame (110), the heat transfer device (106) providing a first heat transfer path, in which one or more phase-change modules (108) are configured to distribute and store heat during a period of reduced heat dissipation or reduced cooling, and characterized in that the first heat transfer path is provided during the period of reduced heat dissipation or reduced cooling and the first heat transfer path is different from a second heat transfer path during a period of heat dissipation or cooling in standard steady state.

2. Thermal management system (200) according to claim 1, wherein the heat transfer device (106) comprises at least one heat pipe (118) disposed adjacent to the metal frame (110), such that the one or more phase-change modules (108) incorporated in the metal frame (110) are disposed above, below, on one or more sides of the at least one heat pipe (118), or a combination thereof.

3. Thermal management system (200) according to claim 2, wherein the heat transfer device (106) comprises at least one heat diffuser (142) which is disposed adjacent to at least one electronic component (104).

4. Thermal management system (200) according to claim 3, wherein the heat transfer device (106) comprises an oscillating heat pipe (136) having a first plurality of channels incorporated in at least one heat diffuser (142) and forming a first channel pattern.

5. Thermal management system (200) according to claim 4, wherein the oscillating heat pipe (136) further comprises a second plurality of channels forming a second channel pattern, such that the second channel pattern is formed in spaces that are unoccupied by the first channel pattern.

6. Thermal management system (200) according to claim 5, wherein the second plurality of channels are configured to receive one or more phase-change modules (108).

7. Thermal management system (200) according to any one of claims 3 to 6, further comprising a metallic layer (130) for containing one or more phase-change modules (108) in at least one opening of the metallic frame (110).

8. Thermal management system (200) according to claim 7, wherein the metallic layer (130) comprises copper and is disposed on at least one opening of the metallic frame (110) by welding, brazing, soldering or thermal epoxy.

9. Thermal management system (200) according to any one of claims 7 or 8, wherein at least one opening in the metal frame (110) comprises a pocket.

10. Thermal management system (200) according to claim 9, wherein at least one opening in the metal frame (110) comprises a T-shaped pocket, the T-shaped pocket having a pair of rims (128) for receiving the metal layer (130).

11. Thermal management system (200) according to any one of the preceding claims, wherein the metal frame (110) comprises aluminum, copper, or alloys thereof.

12. Thermal management system (200) according to any one of the preceding claims, wherein the reduced heat dissipation period or reduced cooling is due to operating conditions including high altitude, high acceleration, hypersonic speed, intermittent peaks in computing power utilization, or a combination thereof.

13. Printed circuit board assembly (100) comprising: a bare printed circuit board (102) having at least one electronic component (104) which generates heat; one or more phase-change modules (108) comprising phase-change materials for distributing and storing heat; a metal frame (110) coupled to the bare printed circuit board (102) and in thermal contact with the at least one electronic component (104), the metal frame (110) further having at least one opening for receiving the one or more phase-change modules (108);and a heat transfer device (106) in thermal contact with one or more of the electronic component(s) (104) and the metal frame (110), the heat transfer device (106) providing a first heat transfer path, in which one or more phase-change modules (108) are configured to distribute and store heat during a period of reduced heat dissipation or reduced cooling, and characterized in that the first heat transfer path is provided during the period of reduced heat dissipation or reduced cooling and the first heat transfer path is different from a second heat transfer path during a period of heat dissipation or cooling in standard steady state.

14. Printed circuit board assembly (100) according to claim 13, wherein the heat transfer device (106) comprises at least one heat pipe disposed adjacent to the metal frame (110), such that the one or more phase-change modules (108) incorporated in the metal frame (110) are disposed above, below, on one or more sides of the at least one heat pipe, or a combination thereof.

15. Printed circuit board assembly (100) according to claim 14, wherein the heat transfer device (106) comprises at least one heat diffuser (142) which is disposed adjacent to at least one electronic component (104).

16. Printed circuit board assembly (100) according to claim 15, wherein the heat transfer device (106) comprises an oscillating heat pipe (136) having a first plurality of channels incorporated into at least one heat diffuser (142) and forming a first channel pattern.

17. Printed circuit board assembly (100) according to claim 16, wherein the oscillating heat pipe (136) further comprises a second plurality of channels forming a second channel pattern, such that the second channel pattern is formed in the spaces which are unoccupied by the first channel pattern.

18. Printed circuit board assembly (100) according to claim 17, wherein the second plurality of channels are configured to receive one or more phase-change modules (108).

19. Printed circuit board assembly (100) according to any one of claims 15 to 18, further comprising a metallic layer (130) for containing one or more phase-change modules (108) in at least one opening of the metallic frame (110).

20. Printed circuit board assembly (100) according to claim 19, wherein the metal layer (130) comprises copper and is disposed on one or more of the opening(s) of the metal frame (110) by welding, brazing, soldering or thermal epoxy.

21. Printed circuit board assembly (100) according to any one of claims 19 or 20, wherein at least one opening in the metal frame (110) includes a pocket.

22. Printed circuit board assembly (100) according to claim 21, wherein at least one opening in the metal frame (110) comprises a T-shaped pocket, the T-shaped pocket having a pair of rims (128) for receiving the metal layer (130).

23. Printed circuit board assembly (100) according to any one of claims 13 to 22, wherein the metal frame (110) comprises aluminum, copper, or alloys thereof.

24. Printed circuit board assembly (100) according to any one of claims 13 to 23, wherein the reduced heat dissipation period or reduced cooling is due to operating conditions including high altitude, high acceleration, hypersonic speed, intermittent computing power, or a combination thereof.

25. A method for manufacturing a printed circuit board assembly (100) comprising at least one electronic component (104) that generates heat, the method comprising the steps of: a) form at least one opening in a metal frame (110) to receive at least one electronic component (104); b) form at least one opening in the metal frame (110) to receive one or more phase-change modules (108), the one or more phase-change modules (108) comprising a phase-change material for distributing and storing heat; c) fill at least one opening of the one or more phase-change modules (108);and d) fix a metallic layer (130) on at least one opening to contain the one or more phase-change modules (108) in at least one opening of the metal frame (110), e) form at least one groove (126) in the metal frame (110) to come into contact with a surface of a heat transfer device (106), so that the heat transfer device (106) is in thermal contact with one or more of the electronic component(s) (104) and the metal frame (110), the heat transfer device (106) further providing a first heat transfer path.;

26. A method according to claim 25, wherein the heat transfer apparatus (106) comprises at least one heat pipe, the at least one heat pipe being disposed at least partially inside the groove (126), such that the one or more phase-change modules (108) incorporated in the metal frame (110) are disposed above, below, on one or more sides of the at least one heat pipe, or a combination thereof.

27. ​​A method according to any one of claims 25 or 26, wherein at least one opening in the metal frame (110) comprises a T-shaped pocket, the T-shaped pocket having a pair of rims (128) for receiving the metal layer (130).

28. A method according to any one of claims 25 to 27, wherein one or more phase-change modules (108) are configured to distribute and store heat during a period of reduced heat dissipation or reduced cooling.

29. A method according to claim 28, wherein the first heat transfer path is provided during the period of reduced heat dissipation or reduced cooling, and the first heat transfer path is different from a second heat transfer path of heat during a period of heat dissipation or cooling under standard steady-state conditions.

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