Integrated heat sink and air plenum for an integrated circuit for heat generation

Abstract

The electronic device includes an integrated circuit and a heat exchanger. The heat exchanger includes a heat pipe and a first plurality of cooling fins and a second plurality of cooling fins. The heat pipe is thermally coupled to the integrated circuit and has an evaporator section and a condenser section, wherein the condenser section extends away from the evaporator section. The first plurality of cooling fins are attached to the condenser section and are close to the evaporation section, and when the cooling fluid flows through the first plurality of cooling fins at a first velocity, a static pressure chamber with a first associated pressure drop is formed. The second plurality of cooling fins are attached to the condenser section and are away from the evaporation section, and when the cooling fluid flows through the second plurality of cooling fins at a first velocity, a flow path with a second associated pressure drop is formed.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of priority of U.S. Provisional Patent Application No. 62 / 788,659, filed on Jan. 4, 2019, with the title "Integrated Heat Sink and Air Plenum for a Heat-Generating Integrated Circuit", and claims the benefit of priority of U.S. Patent Application No. 16 / 555,711, filed on Aug. 29, 2019, with the title "Integrated Heat Sink and Air Plenum for a Heat-Generating Integrated Circuit". The subject matter of these related applications is hereby incorporated herein by reference.

[0003] Background of the Invention Technical Field

[0004] Embodiments of the present invention generally relate to computer systems, and more particularly, to an integrated heat sink and an air plenum for a heat-generating integrated circuit. Background Art

[0005] In modern computing devices, central processing units (CPUs), graphics processing units (GPUs), and other integrated circuits (ICs) generate a large amount of heat during use. To ensure the normal operation of the integrated circuits and the computing devices, this heat needs to be removed. For example, a single high-power chip, such as a CPU or a GPU, can generate hundreds of watts of heat during operation. If this heat is not effectively removed, the temperature of the chip will rise to a point where the chip is at risk of being damaged. To prevent thermal damage during operation, many systems implement clock speed throttling when the operating temperature of the processor exceeds a certain threshold. Therefore, in these systems, the processing speed of high-power chips is limited by the chip design and how effectively heat is removed from the chips.

[0006] To reduce the impact of thermal constraints on the performance of high-power chips, heat exchangers can be employed, which allow high-power chips to operate at higher processing speeds and generate larger amounts of heat. As is well known, a heat exchanger transfers heat from the chip to the ambient air, and then the air carries the heat away from the chip. The heat exchanger can include passive devices such as a heatsink, or more complex heat transfer devices such as heat pipes. A heatsink typically includes an array of fins that increases the effective surface area of the chip exposed to the ambient air, while a heat pipe relies on a phase change (such as the evaporation of a liquid) to effectively transfer heat between two solid interfaces. In some cases, heat pipes are used in combination with heatsinks to increase the amount of heat that can be removed from a high-power chip.

[0007] Despite the use of heat exchangers and other thermal solutions, as the processing capabilities of CPUs, GPUs, and other integrated circuits continue to increase, the processing speed of such high-power chips remains limited by the rate at which heat can be removed from these chips. Additionally, many modern chip packaging architectures add thermal resistance between the high-power chip and the associated heat exchanger. For example, some chip packaging architectures now include structures between the high-power chip and the heat exchanger, such as a protective cover or additional heat-generating chips stacked on top of the heat-generating chip. These intervening thermal resistances reduce the efficiency of the heat exchanger.

[0008] As previously mentioned, there is a need in the art for more effective techniques to remove heat from integrated circuits during operation. Summary of the Invention

[0009] One embodiment of the present invention describes an electronic device that includes an integrated circuit (IC) and a heat exchanger. The heat exchanger includes at least one heat pipe, as well as a first plurality of cooling fins and a second plurality of cooling fins. The at least one heat pipe is thermally coupled to the integrated circuit and has an evaporator section and a condenser section, where the condenser section extends away from the evaporator section. The first plurality of cooling fins is attached to the condenser section and is close to the evaporation section, and forms a plenum with a first associated pressure drop when a cooling fluid flows through the first plurality of cooling fins at a first velocity. The second plurality of cooling fins is attached to the condenser section and is away from the evaporation section, and forms a flow path with a second associated pressure drop when the cooling fluid flows through the second plurality of cooling fins at the first velocity.

[0010] Relative to the prior art, at least one technical advantage of the disclosed heat exchanger design is that heat generated by the IC can be removed from the IC more effectively, enabling the IC to operate at a higher processing speed without overheating. Another advantage is that the pressure drop across the disclosed heat exchanger is typically less than the pressure drop across a conventional heat exchanger, which reduces fan power consumption and fan noise relative to conventional heat exchanger designs. These technical advantages provide one or more more advanced technologies compared to prior art methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] To understand the above features of each embodiment in detail, the inventive concept briefly summarized above can be described more specifically by referring to each embodiment, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only show typical embodiments of the inventive concept and should not be regarded as limiting the scope in any way, and there are other equally effective embodiments.

[0012] Figure 1A is a perspective view of a heat exchanger according to various embodiments of the present invention;

[0013] Figure 1B is according to various embodiments of the present invention Figure 1A side view of the heat exchanger;

[0014] Figure 2 is according to various embodiments of the present invention Figure 1A and Figure 1B perspective view of the heat pipe array;

[0015] Figure 3 is according to various embodiments of the present invention Figure 1A and Figure 1B end view of the heat sink;

[0016] Figure 4 is an end view of a heat sink, an integrated circuit (IC), and a heat sink fin with a heat pipe installed according to various embodiments of the present invention;

[0017] Figure 5 is a perspective view of a heat sink according to various embodiments of the present invention, the heat sink including a heat pipe, a heat sink fin with a plate installed, and a heat sink fin with a heat pipe installed;

[0018] Figure 6A is a schematic end view of heat according to various embodiments of the present invention;

[0019] Figure 6B is according to various embodiments of the present invention Figure 6A schematic side view of the heat sink;

[0020] Figure 7 is a perspective view of a first heat pipe array coupled to a substrate surface and a second heat pipe array coupled to the heat pipes of the first array according to various embodiments of the present invention;

[0021] Figure 8 is according to various embodiments of the present invention Figure 7 perspective view of the first heat pipe array coupled to the substrate in;

[0022] Figure 9in accordance with various embodiments of the present invention Figure 7 Bottom perspective view of the first heat pipe array in

[0023] Figure 10 Perspective view of a substrate configured to mate with a smaller substrate coupled to a heat pipe, in accordance with various embodiments of the present invention;

[0024] Figure 11 Perspective view of a heat exchanger in accordance with other various embodiments of the present invention;

[0025] Figure 12 Schematic side view of an electronic device including a plurality of heat exchangers and integrated circuits mounted on a single printed circuit board, in accordance with various embodiments of the present invention; and

[0026] Figure 13 in accordance with various embodiments of the present invention including Figure 12 Schematic diagram of a computing device including one or more electronic devices of

[0027] Figure 14 Perspective view of a heat exchanger in accordance with various embodiments of the present invention.

[0028] Figure 15 in accordance with various embodiments of the present invention Figure 14 Side view of the heat exchanger of

[0029] Figure 16 Side view of a heat exchanger in accordance with various embodiments of the present invention.

[0030] Figure 17 Side view of a heat exchanger in accordance with various embodiments of the present invention.

[0031] Figure 18A Schematically shows a side view of a heat exchanger in accordance with various embodiments of the present invention.

[0032] Figure 18B Schematically shows a side view of a heat exchanger in accordance with various embodiments of the present invention.

[0033] Figure 18C Schematically shows a side view of a heat exchanger in accordance with various embodiments of the present invention.

[0034] Figure 19A Schematically shows a perspective view of a heat exchanger omitting cooling fins and auxiliary metal plates in accordance with various embodiments of the present invention.

[0035] Figure 19B Schematically shows a perspective view of a heat exchanger omitting cooling fins but including an auxiliary metal plate in accordance with various embodiments of the present invention.

[0036] Figure 19C A perspective view of a heat exchanger according to various embodiments of the present invention is schematically shown, in which cooling fins are omitted, but an auxiliary metal plate, the cooling fins to which the plates are attached, and a substrate are shown.

[0037] Figure 19D A perspective view of a heat exchanger according to various embodiments of the present invention is schematically shown, in which cooling fins are omitted, but an IC contact surface of a metal plate in contact with an IC is shown.

[0038] Figure 20 A cross-sectional view of an evaporator portion and a metal plate in contact with an IC according to an embodiment of the present invention is schematically shown.

[0039] For clarity, where applicable, the same reference numerals are used to refer to the same elements common between the figures. The features of one embodiment may be incorporated into other embodiments without further recitation. Detailed Description

[0040] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the various embodiments. However, it will be apparent to one of ordinary skill in the art that the concepts of the present invention may be practiced without one or more of these specific details.

[0041] Heat Exchanger Description

[0042] Figure 1A is a perspective view of a heat exchanger 100 according to various embodiments of the present invention. Figure 1B is a side view of a heat exchanger 100 according to various embodiments of the present invention. The heat exchanger 100 is a heat exchanger for an integrated circuit (IC) 101 and includes an integrated heat sink 120 and a low-pressure-drop air plenum 130. The heat exchanger 100 and the IC 101 together form an electronic device that can be mounted on a printed circuit board (PCB) 104. In an embodiment, the heat sink 120 includes one or more heat pipes 140 thermally coupled to the IC 101 and a plurality of cooling fins 121 attached to the heat pipes 140.

[0043] In some embodiments, IC 101 includes a single microchip, such as a graphics processing unit (GPU) or a central processing unit (CPU). Alternatively, in some embodiments, IC 101 includes multiple microchips, such as processor die 101A and one or more memory die stacks 101B, all of which are mounted on a common package substrate 101C. In such an embodiment, the package substrate 101C may be configured to mount the IC 101 to the PCB 104, e.g., via solder balls (not shown). Additionally, in such an embodiment, the IC 101 may include a package lid 101D that protects the processor die 101A and one or more memory die stacks 101B from physical damage but also increases the thermal resistance associated with the packaging of the IC 101. Further, in some multi-microchip embodiments, the IC 101 may include other chip configurations, such as a system-on-chip (SoC) configuration.

[0044] The heat pipe 140 is a sealed container, such as a copper tube, that includes an evaporative working fluid (not shown), such as water or alcohol. Figure 2 An embodiment of the heat pipe 140 is shown. Figure 2 is a perspective view of an array of multiple heat pipes 140 according to various embodiments of the present invention. The heat pipes 140 effectively transfer heat from the IC 101 to the cooling fin 121 (not shown for clarity) through a combination of evaporation and condensation, and further to the cooling air passing through the cooling fin 121. More specifically, in the heat pipe 140, the evaporation of the working fluid into vapor occurs in the evaporator section 241 of each heat pipe 140, while the condensation of the working fluid occurs in one or more condenser sections 242. Each evaporator section 241 is coupled to the surface from which thermal energy is to be removed, while each condenser section 242 extends away from the surface from which thermal energy is to be removed. In Figure 2 the embodiment shown, each heat pipe 140 includes two condenser sections 242, but in other embodiments, each heat pipe 140 may include more or fewer than two condenser sections 242. The condensed working fluid from the condenser section 242 flows to the corresponding evaporator section 241, where thermal energy from the IC 101 is absorbed and the working fluid is vaporized. The vapor then moves to the condenser section 242 and condenses in the condenser section 242, releasing the latent heat. In some embodiments, each heat pipe 140 also includes a wicking structure or material (not shown) on some or all of the inner surfaces to facilitate the return of the condensed cooling liquid to the evaporator section 241 of the heat pipe 140.

[0045] Return Figure 1A and Figure 1B, in the illustrated embodiment, the heat pipe 140 is mounted on a metal plate 150 that is thermally coupled to the IC 101, such as a copper plate or an aluminum plate. In these embodiments, the metal plate 150 may be thermally coupled to the main surface 101E of the IC 101 via a thermal interface material (TIM) 151 (e.g., a high thermal conductivity paste). The metal plate 150 spreads heat over a surface area that is larger than the surface area of the IC 101. Thus, a greater number of heat pipes 140 can be thermally coupled to the IC 101 on the metal plate 150 as compared to when directly attached to the IC 101. In some embodiments, high-density heat pipes 140 are mounted on the metal plate 150 in a high-density heat pipe region 152, and low-density heat pipes 140 are mounted on the metal plate 150 in a low-density heat pipe region 153. Thus, in such embodiments, a portion of the metal plate 150 that is closest to the IC 101 (and thus at the highest temperature during operation of the IC 101) has a higher density of heat pipes 140 coupled thereto. In contrast, a lower temperature portion of the metal plate 150, such as the low-density heat pipe region 153, has a lower density of heat pipes 140 coupled thereto.

[0046] The heat sink 121 can be any material that is effectively thermally conductive, such as copper or aluminum. The heat sink 121 is attached along the condenser portion 242 of the heat pipe 140 and is oriented to allow cooling air to flow in the air flow direction 103 between the heat sink 121 and the past condenser portion 242. As shown, the heat sink 121 forms one or more low-pressure-drop static pressure chambers 130 and high-pressure-drop paths 102. The one or more low-pressure-drop static pressure chambers 130 form a path for cooling the air flowing near the evaporator portion 241, and the high-pressure-drop path 102 is for cooling the air flowing away from the evaporator portion 241 of the heat pipe 140. The low-pressure-drop static pressure chambers 130 cause the relatively high-speed, lower-temperature cooling air to flow through a portion of the condenser portion 242 that is near the IC 101, while the high-pressure-drop path 102 causes the relatively low-speed, higher-temperature cooling air to flow through a portion of the condenser portion 242 that is away from the IC 101. Thus, the portion of the heat pipe 140 that is closest to the IC 101 (which most affects the temperature of the IC 101) is exposed to the higher-speed, lower-temperature cooling air. For example, the lower portion 143 of the heat pipe 140 disposed in the high-density heat pipe region 152 is exposed to such higher-speed, lower-temperature cooling air, as Figure 1A shown by the velocity profile 190 included therein.

[0047] The velocity curve 190 graphically illustrates that the velocity of the cooling air (or other cooling fluid) passing through the cooling fins 121 is a function of the height h above the metal plate 150. The higher pressure drop generated by the cooling air flowing through the cooling fins 121 via the high-pressure drop path 102 causes the cooling air to flow through the cooling fins 121 at a lower velocity than via the low-pressure drop air plenum 130. That is, when the cooling air flows through the cooling fins 121, in the low-pressure drop region 125 corresponding to the low-pressure drop air plenum 130, the length of the cooling fins 121 is reduced, resulting in a smaller pressure drop generated at a specific velocity than the pressure drop generated in the adjacent high-pressure drop region 126 (corresponding to the high-pressure drop path 102) at the same specific velocity. Therefore, the velocity of the cooling air flowing in the low-pressure drop region 125 is significantly higher than that in the high-pressure drop region 126. Since the higher-velocity cooling air flows through the lower portion of the heat pipe 140 within the low-pressure drop region 125, the highest temperature portion of the heat pipe 140 can transfer more heat to the cooling air, and the heat sink 120 can transfer heat from the IC 101 more effectively than a conventional heat sink.

[0048] In addition, the cooling air flowing through the low-pressure drop air plenum 130 and passing through the lower portion of the heat pipe 140 (within the low-pressure drop region 125) is not pre-heated by passing along the cooling fins 121 in the low-density heat pipe region 153. Instead, there are few or no cooling fins 121 in the low-density heat pipe region 153 near the lower portion 143 of the heat pipe 140 in the high-density heat pipe region 152. Therefore, little or no heat is transferred to the cooling air before it flows through the lower portion 143. Since the cooling air flowing through the lower portion 143 is not pre-heated by passing along the cooling fins 121, more heat can be transferred from the highest temperature portion (i.e., the lower portion 143) of the heat pipe 140 to the cooling air, and the heat sink 120 can transfer heat from the IC 101 more effectively than a conventional heat sink.

[0049] According to various embodiments, the low-pressure drop air plenum 130 is formed by terminating a portion of the cooling fins 121 before the edge region 123 and / or the edge region 124 of the heat sink 120. Therefore, the length of the portion of the cooling fins 121 terminated before the edge regions 123 and 124 is shorter in the air flow direction 103 than the cooling fins forming the high-pressure drop path 102 and extending from the edge region 123 to the edge region 124. For example, in some embodiments, some or all of the cooling fins 121 forming the low-pressure drop air plenum 130 in this portion of the cooling fins 121 terminate at the interface region between the high-density heat pipe region 152 and the low-density heat pipe region 153. In some embodiments, each of the cooling fins 121 forming the low-pressure drop air plenum 130 terminates at a different length corresponding to the termination profile 155. In Figure 1A and Figure 1BIn the illustrated embodiment, the termination profile 155 is depicted as a parabolic function of the length of certain of the cooling fins 121. In other embodiments, the termination profile 155 can be a linear function of the length of certain of the cooling fins 121, which length is equal to or near the minimum length of the cooling fins 121 closest to the IC chip 101. In other embodiments, the termination profile 155 can be a step function; that is, in these embodiments, the cooling fins 121 forming the low pressure drop air plenum 130 have the same (shorter) length, while the cooling fins 121 forming the high pressure drop path 102 have the same (longer) length and terminate at the edge regions 123 and / or 124 of the heat sink 120. In other embodiments, any other suitable termination profile 155 can be used to cause the relatively faster cooling air to flow through the low pressure drop air plenum 130 and the relatively slower cooling air to flow through the high pressure drop path 102.

[0050] In Figure 1A and Figure 1B the illustrated embodiments, the low pressure drop air plenum 130 includes the termination profile 155 at the edge regions 123 and 124. In other embodiments, the low pressure drop air plenum 130 is formed at the edge region 123 or the edge region 124.

[0051] Substrate cooling fin

[0052] In some embodiments, the condenser portion 242 of the heat pipe 140 includes one or more straight segments extending outwardly from the IC 101 and the metal plate 150. In such embodiments, the condenser portion 242 can also include one or more curved segments that connect the straight segments of the condenser portion 242 to the corresponding evaporator portions 241. In such embodiments, it is generally impractical to attach the cooling fins 121 along such curved portions to the heat pipe 140. As a result, the heat sink 120 can include an airflow region 109 that is free of cooling fins 121 and is disposed between the metal plate 150 and the low pressure drop air plenum 130. As shown, the airflow region 109 includes the curved portion of the heat pipe 140 that connects the straight segments of the condenser portion 242 to the corresponding evaporator portions 241.

[0053] According to some embodiments, one or more sets of plate-mounted cooling fins are attached to the metal plate 150 and extend outwardly from the metal plate 150 into the airflow region 109. Such plate-mounted cooling fins effectively add more surface area to the metal plate 150, further improving the efficiency of the heat sink 120 in transferring thermal energy away from the IC 101. Figure 3 is an end view of the heat sink 120, the IC 101, and the plate-mounted cooling fin 356 in accordance with various embodiments of the present invention. Figure 3The view shown is looking along the air flow direction 103. As shown, the fin 356 with the plate mounted extends from the metal plate 150 into the air flow region 109. Thus, in such an embodiment, in addition to the low pressure drop region 125 and the high pressure drop region 126, there are also fins in the air flow region 109. Therefore, the heat removal efficiency of the heat sink 120 is improved. In some embodiments, the fin 356 with the plate mounted is attached to a mounting plate 357, which in turn is coupled, welded, or otherwise attached to the metal plate 150.

[0054] Alternatively or additionally, in some embodiments, the fins extending into the air flow region 109 are mounted on the surface of one or more heat pipes 140 or otherwise thermally coupled to the surface of one or more heat pipes 140. Figure 4 One such embodiment is shown. Figure 4 is an end view of the heat sink 120, the IC 101, and the fin 456 with the heat pipe mounted according to various embodiments of the present invention. Figure 4 The view shown is looking along the air flow direction 103. As shown, the fin 456 with the heat pipe mounted (shown in cross - hatching for clarity) extends into the air flow region 109 and transfers heat from the surface 441 (dashed line) of one or more heat pipes 140, thereby extending the heat exchange surface into the air flow region 109. In some embodiments, the fin 456 with the heat pipe mounted is attached to a mounting plate 457, which in turn is coupled, welded, or otherwise attached to the surface 441 or both the surface 441 and the metal plate 150. The fin 456 with the heat pipe mounted can be arranged in portions of the air flow region 109 where the fin 356 with the plate mounted cannot be easily positioned, as Figure 5 shown.

[0055] Figure 5 is a perspective view of a heat sink 520 according to various embodiments of the present invention, the heat sink 520 including heat pipes 140, fins 356 with plates mounted, and fins 456 with heat pipes mounted. In Figure 5 for clarity, the fin 121 is omitted. As shown, the fin 456 with the heat pipe mounted can be located between the two condenser portions 242 of each heat pipe 140, thereby improving the heat removal efficiency of the heat sink 520.

[0056] Substrate heat pipe

[0057] In some embodiments, the heat sink can include a set of one or more heat pipes configured to convey thermal energy outward along a metal plate coupled to the IC. Thus, the temperature of the portion of the metal plate away from the IC increases, further improving the heat removal efficiency of the heat sink. Figure 6A and Figure 6B shows one such embodiment.

[0058] Figure 6A is a schematic end view of a heat sink 620 in accordance with various embodiments of the present invention. Figure 6A The view of the heat sink 620 in [the figure] is obtained along the air flow direction 103, i.e., the air flow direction 103 is into the page. Figure 6B is a schematic side view of a heat sink 620 in accordance with various embodiments of the present invention. In Figure 6A and Figure 6B the illustrated embodiment, the heat sink 620 includes heat pipes 640 for transferring thermal energy away from the IC 101 and through the substrate 650 of the heat sink 620. Figure 6B Also shown are a low pressure drop air plenum 130, heat pipes 140, and finned plates 356. The heat pipes 640 are formed inside and / or on the surface of the metal plate 650 and improve the heat removal efficiency of the heat pipes 140 coupled to the metal plate 650 in the low density heat pipe region 153. Specifically, the heat pipes 640 improve the heat removal efficiency of such heat pipes 140 by raising the temperature of portions of the metal plate 650 in the low density heat pipe region 153 using the thermal energy transferred from the IC 101.

[0059] In some embodiments, heat pipes that transfer thermal energy away from an integrated circuit through the substrate of the heat sink are coupled to the surface of the substrate. Figure 7 、 Figure 8 and Figure 9 illustrate such an embodiment.

[0060] Figure 7 is a perspective view of a first array 710 of heat pipes 720 coupled to the surface of a substrate 750 and a second array 730 of heat pipes 740 coupled to the heat pipes 720 of the first array 710 in accordance with various embodiments of the present invention. For clarity, Figure 7 the finned plates 121 that are normally coupled to the heat pipes 740 are omitted. The heat pipes 720 of the first array 710 transfer thermal energy away from an integrated circuit ( Figure 7 not shown in [the figure]) and transfer it to the heat pipes 720 of the first array 710. To this end, some or all of the heat pipes 720 are thermally and mechanically coupled to the evaporator portions 741 of each of the heat pipes 740 of the second array 730. Thus, the heat transferred away from the substrate by the heat pipes 720 heats the evaporator portions 741 of the heat pipes 740.

[0061] The heat pipe 740 can be coupled to the heat pipe 720 via soldering or any other technically feasible technique. In some embodiments, in addition to the solder used between the heat pipe 740 and the heat pipe 720 to mechanically and thermally couple the heat pipe 740 to the heat pipe 720, a solder fill material (not shown) can be used to fill the air gaps between the heat pipes 720, between the heat pipes 740, and between the first array 710 and the second array 730. In these embodiments, the first array 710 and the second array 730 are more robustly coupled together and the heat transfer between them is enhanced.

[0062] Figure 8 is a perspective view of the first array 710 of heat pipes 720 coupled to a substrate 750 in accordance with various embodiments of the present invention. For clarity, Figure 8 the second array 730 is omitted. As shown, each heat pipe 720 of the first array 710 is coupled to the surface of the substrate 750. In some embodiments, the heat pipes 720 are coupled to the surface of the substrate 750 via a soldering process. In these embodiments, additional solder (not shown) can be used to fill the air gap between the heat pipes 720 and the substrate 750, thereby enhancing the heat transfer from the substrate 750 and the heat pipes 720. In other embodiments, any other technically feasible technique can be used to mechanically and thermally couple the heat pipes 720 to the substrate 750.

[0063] Figure 9 is a bottom perspective view of the first array 710 of heat pipes 720 in accordance with various embodiments of the present invention. As shown, the substrate 750 is coupled to the heat pipes 720 to form an assembly 901. When the first array 710 and the substrate 750 are included in a heat sink, such as Figure 1A and Figure 1B in the heat sink 120, the surface 902 of the substrate 750 is configured to be thermally coupled to an IC (not shown), such as Figure 1A and Figure 1B the IC 101 in. Thus, the assembly 901 is configured to transfer the heat generated by the IC to the heat pipes 720 through the substrate 750.

[0064] In Figure 7 , Figure 8 and Figure 9 the illustrated embodiments, the substrate 750 is configured to be coupled to the middle portion of each heat pipe 720, rather than along most or all of the length of each heat pipe 720. In such embodiments, the assembly 901 can be further configured to mate with a larger substrate that includes appropriately configured openings for the substrate 750. Figure 10 An embodiment of such a larger substrate is shown in.

[0065] Figure 10is a perspective view of a substrate 1050 according to various embodiments of the present invention, the substrate being configured to mate with a smaller substrate to which a heat pipe is coupled. As shown, the substrate 1050 includes an opening 1051 that is configured to substantially match the shape of a smaller substrate (e.g., the substrate 750 among Figure 7 , Figure 8 , and Figure 9 ) to which the heat pipe 720 is coupled. Additionally, in some embodiments, the substrate 1050 includes a wall 1052 that extends away from a central surface 1053 and is configured to accommodate the heat pipe 720 when the assembly 901 is coupled to the substrate 1050. In some embodiments, the wall 1052 is configured to at least partially surround the heat pipe 720 when the assembly 901 is coupled to the substrate 1050. Thus, in some embodiments, the heat pipe 720 can first be coupled to the substrate 750 to form the assembly 901, and then the assembly 901 can be coupled to the substrate 1050 by inserting the substrate 750 into the opening 1051. The assembly 901 and the substrate 1050 can then be mechanically and thermally coupled to each other, e.g., via a welding process. In such embodiments, additional welding material can be employed to fill the air gaps between the heat pipe 720 and the wall 1052 and / or between the heat pipe 720 and the central surface 1053. Figure 7 and Figure 8 and Figure 9 in which the heat pipe 720 is coupled. Further, in some embodiments, the substrate 1050 includes a wall 1052 that extends away from a central surface 1053 and is configured to accommodate the heat pipe 720 when the assembly 901 is coupled to the substrate 1050. In some embodiments, the wall 1052 is configured to at least partially surround the heat pipe 720 when the assembly 901 is coupled to the substrate 1050. Thus, in some embodiments, the heat pipe 720 can first be coupled to the substrate 750 to form the assembly 901, and then the assembly 901 can be coupled to the substrate 1050 by inserting the substrate 750 into the opening 1051. The assembly 901 and the substrate 1050 can then be mechanically and thermally coupled to each other, e.g., via a welding process. In such embodiments, additional welding material can be employed to fill the air gaps between the heat pipe 720 and the wall 1052 and / or between the heat pipe 720 and the central surface 1053. Figure 9 the assembly 901, and then the assembly 901 can be coupled to the substrate 1050 by inserting the substrate 750 into the opening 1051. The assembly 901 and the substrate 1050 can then be mechanically and thermally coupled to each other, e.g., via a welding process. In such embodiments, additional welding material can be employed to fill the air gaps between the heat pipe 720 and the wall 1052 and / or between the heat pipe 720 and the central surface 1053.

[0066] In some embodiments, the wall 1052 of the substrate 1050 includes one or more notches 1054 or other mechanical features configured to accommodate a mounting plate for a finned heat sink with a mounted plate. For example, when the finned heat sink 356 with a mounted plate is attached to the mounting plate 357, the notch 1054 can be configured to accommodate a suitably configured tab or other feature of the mounting plate 357. Figure 3 the finned heat sink 356 with a mounted plate is attached to the mounting plate 357, the notch 1054 can be configured to accommodate a suitably configured tab or other feature of the mounting plate 357.

[0067] Figure 11 An embodiment of a heat sink including the features of the above embodiments is shown. Figure 11 is a perspective view of a heat exchanger 1100 according to various other embodiments of the present invention. As shown, the heat exchanger 1100 includes a substrate 1050 with notches 1054 for accommodating a finned heat sink 356 with a mounted plate. The heat exchanger 1100 also includes a finned heat sink 456 with a mounted heat pipe and heat pipes 140 mounted on and coupled to an array of heat pipes 720. The heat pipe 720 is coupled to a substrate 750 and inserted into an opening (not shown) in the substrate 1050.

[0068] Multiple IC configurations

[0069] In some embodiments, multiple ICs can be mounted on a single PCB. In such embodiments, multiple heat exchangers can also be mounted on a single PCB. One such embodiment is shown in Figure 12 below.Figure 12 FIG. 1 is a schematic side view of an electronic device 1201 in accordance with various embodiments of the present invention, the electronic device including a plurality of heat exchangers 1211 and 1212 and a plurality of ICs 101, all mounted on a single PCB 1202. In some embodiments, heat exchangers 1211 and 1212 are positioned on the PCB 1201 such that cooling air (or any other cooling fluid) can flow sequentially through a first heat exchanger of the electronic device (e.g., heat exchanger 1211) and a second heat exchanger of the electronic device (e.g., heat exchanger 1212). That is, heat exchangers 1211 and 1212 are positioned on the PCB 1201 such that cooling air can flow through the first heat exchanger and then through the second heat exchanger. For example, as Figure 12 shown, the fins of the heat pipes coupled to heat exchanger 1211 are oriented parallel to the fins of the heat pipes coupled to heat exchanger 1212. Accordingly, the flow of the cooling fluid through heat exchangers 1211 and 1212 sequentially is facilitated.

[0070] Computing device

[0071] In some embodiments, an electronic device 1201 including a plurality of ICs and heat exchangers is included in a larger computing device. One such embodiment is shown in Figure 13 FIG. 2.

[0072] Figure 13 FIG. 2 is a schematic view of a computing device 1300 in accordance with an embodiment of the present invention, the device including one or more electronic devices 1201. Computing device 1300 may be configured for use in high performance applications, such as in a data center. Accordingly, computing device 1300 includes a plurality of electronic devices 1201. In the embodiment shown in Figure 13 FIG. 2, the computing device includes a plurality of trays 1310 of electronic devices 1201. Additionally, in some embodiments, computing device 1300 includes a fan box 1301 having a plurality of fans configured to force cooling air through the heat exchangers included in the electronic devices 1201. In some embodiments, computing device 1300 further includes additional ICs, PCBs, and other electronic components 1302 that are cooled by air forced through the heat exchangers included in the electronic devices 1201. Although the heat transfer efficiency of the heat exchangers included in the electronic devices 1201 is superior to that of conventional heat exchangers, it should be noted that the low pressure drop air plenum 130 included in the heat exchangers of the electronic devices 1201 typically has a pressure drop similar to or even smaller than that of conventional heat exchangers.

[0073] Alternative plenum configurations for heat exchangers

[0074] In the above embodiments, the cooling fins of the heat exchanger are configured to form one or more low-pressure-drop air plenums that direct relatively high-speed, relatively low-temperature cooling air to flow past the heat pipe condenser portion near the IC. At the same time, the high-pressure-drop path through the cooling fins of the heat exchanger causes relatively low-speed, relatively high-temperature cooling air to flow past portions of the heat pipe condenser portion located at the distal end of the IC. In some alternative embodiments, one or more low-pressure-drop air plenums are formed by a set of cooling fins having a greater fin pitch than one or more other sets of cooling fins. One such embodiment is as Figure 14 and Figure 15 shown.

[0075] Figure 14 is a perspective view of a heat exchanger 1400 in accordance with various embodiments of the present invention. Figure 15 is a side view of a heat exchanger 1400 in accordance with various embodiments of the present invention. The heat exchanger 1400 is a heat exchanger for an IC 101 and includes an integrated heat sink 1420 with a low-pressure-drop air plenum 1430.

[0076] The heat exchanger 1400 is similar to the heat exchanger 100 in FIG. 1, except that the low-pressure-drop air plenum 1430 is formed by a first set 1525 of cooling fins 121 having a fin pitch 1501 greater than that of one or more other sets of cooling fins, such as a second set 1526 of cooling fins 121. As shown, the second set 1525 is configured with cooling fins 121 having a fin pitch 1502 significantly less than the fin pitch 1501. Thus, the pressure drop generated by the cooling air flowing through the second set 1526 at a particular speed is greater than the pressure drop generated by the cooling air flowing through the first set 1525 at the same speed. Accordingly, in operation, the speed of the cooling air flowing through the low-pressure-drop region formed by the low-pressure-drop air plenum 1430 is significantly higher than the speed of the cooling air flowing through the high-pressure-drop region formed by the second set 1526. Additionally, the first set 1525 is disposed closer to the IC 101, while the second set 1526 is disposed farther from the IC 101. Since the speed of the cooling air flowing through the lower portion of the heat pipe 140 within the low-pressure-drop air plenum 1430 is higher, the highest temperature portion of the heat pipe 140 can transfer more heat to the cooling air, and the heat sink 1420 can more effectively transfer heat away from the IC 101 compared to a conventional heat sink.

[0077] In Figure 14 and Figure 15 the illustrated embodiments, each cooling fin 121 in the first set 1525 and the second set 1526 has a fin length 1527. In other embodiments, the cooling fins 121 in the first set 1525 have a different fin length than the cooling fins 121 in the second set 1526. One such embodiment is shown in Figure 16 as

[0078] Figure 16 is a side view of a heat exchanger 1600 according to various embodiments of the present invention. The heat exchanger 1600 is a heat exchanger for an IC 101 and includes an integrated heat sink 1620 and a low-pressure-drop air plenum 1630. The heat exchanger 1600 is similar to Figure 14 and Figure 15 the heat exchanger 1400 therein, except that the low-pressure-drop air plenum 1630 is formed by a first group 1625 of cooling fins 121, and the first group 1625 of cooling fins 121 has a larger fin pitch 1601 and a shorter length 1627 than one or more other groups of cooling fins (such as the second group 1626). As shown, the second group 1625 is configured with cooling fins 121 having a fin pitch 1602 significantly smaller than the fin pitch 1601 and a fin length 1628 significantly greater than the length 1627. Thus, the pressure drop generated by the cooling air flowing through the second group 1625 at a specific speed is greater than the pressure drop generated by the cooling air flowing through the first group 1626 at the same speed.

[0079] In some embodiments, the multiple groups of cooling fins 121 in the heat exchanger have fin lengths corresponding to termination profiles. That is, the first group of cooling fins 121 in the heat exchanger has a fin length corresponding to a first termination profile, and the second group of cooling fins 121 in the heat exchanger has a fin length corresponding to a second termination profile. One such embodiment is shown in Figure 17 therein.

[0080] Figure 17 is a side view of a heat exchanger 1700 according to various embodiments of the present invention. The heat exchanger 1700 is a heat exchanger for an IC 101 and includes an integrated heat sink 1720 and a low-pressure-drop air plenum 1730. The heat exchanger 1700 is similar to Figure 14 and Figure 15 the heat exchanger 1400 therein, except that the heat exchanger 1700 includes two or more groups of cooling fins 121, where each group of cooling fins 121 has a respective length corresponding to a specific termination profile. Thus, in the embodiment shown in Figure 17 the heat exchanger 1700 includes a first group 1725 of cooling fins 121 having respective lengths corresponding to a first termination profile 1701 and a second group 1726 of cooling fins 121 having respective lengths corresponding to a second termination profile 1702. In such an embodiment, the configuration of the multiple groups of cooling fins 121 (each forming a termination profile) enables further adjustment of the pressure drop and / or the cooling fluid velocity associated with each group of cooling fins. That is, the flow rate of the cooling fluid through the first group 1725 can be selected relative to the flow rate of the cooling fluid through the second group 1726, for example, by modifying the morphology of the first termination profile 1701 and / or the second termination profile 1702.

[0081] In Figure 17 In the illustrated embodiment, the cooling fins 121 of the first group 1725 are formed in the first termination profile 1701 on the leading edge region 1723 and the trailing edge region 1724 of the heat exchanger 1700. In another embodiment, the cooling fins 121 of the first group 1725 are formed in the first termination profile 1701 on either the leading edge region 1723 or the trailing edge region 1724 of the heat exchanger 1700, but not on both. Alternatively or additionally, the cooling fins 121 of the second group 1726 are formed in the second termination profile 1702 on either the leading edge region 1723 or the trailing edge region 1724 of the heat exchanger 1700, but not on both.

[0082] In Figure 17 the illustrated embodiment, the first termination profile 1701 of the first group 1725 is substantially similar to the second termination profile 1702 of the second group 1726. Alternatively or additionally, in some embodiments, the first termination profile 1701 is significantly different from the second termination profile 1702 of the second group 1726. Figures 18A - 18C Examples of such embodiments are shown.

[0083] Figure 18A A side view of a heat exchanger 1810 according to various embodiments of the present invention is schematically shown. In Figure 18A it, the heat exchanger 1810 includes a first portion 1811 of cooling fins (not shown separately for clarity), which are collectively configured to form a first termination profile 1813. In addition, the heat exchanger 1810 includes a second portion 1812 of cooling fins (not shown separately for clarity), which are collectively configured to form a second termination profile 1814. As shown, the first termination profile 1813 is different from the second termination profile 1814.

[0084] Figure 18B A side view of a heat exchanger 1820 according to various embodiments of the present invention is schematically shown. In Figure 18BIn [the figure], the heat exchanger 1820 includes a first portion 1821 of cooling fins (not shown separately for clarity), which are collectively configured to form a first termination profile 1823, and a second portion 1822 of cooling fins (not shown separately for clarity), which are collectively configured to form a second termination profile 1824. Due to the relative shapes of the first termination profile 1823 and the second termination profile 1824, the cooling air flowing through the second portion 1822 at a specific speed generates a higher pressure drop across the heat exchanger 1820 than the cooling air flowing through the first portion 1821 at the same speed. Thus, during operation, more cooling air tends to flow through the first portion 1821 and at a higher speed than through the second portion 1822.

[0085] Figure 18C A side view of a heat exchanger 1830 according to various embodiments of the present invention is schematically shown. In Figure 18C [the figure], the heat exchanger 1830 includes a first portion 1831 of cooling fins (not shown separately for clarity), which are collectively configured to form a first termination profile 1833. Additionally, the heat exchanger 1830 includes a second portion 1832 of cooling fins (not shown separately for clarity), which are collectively configured to form a second termination profile 1834. As shown, the first termination profile 1833 is different from the second termination profile 1834, which significantly affects the flow rate of the cooling air through the first portion 1831 relative to the second portion 1832.

[0086] Alternative heat pipe configurations in a heat exchanger

[0087] In the above embodiment, a first set of heat pipes is thermally coupled to the IC to distribute heat away from the IC, while a second set of heat pipes is thermally coupled to the first set of heat pipes and a plurality of cooling fins. In such an embodiment, each heat pipe in the second set of heat pipes includes an evaporator portion and at least one condenser portion that is perpendicular to the evaporator portion and directly coupled to the plurality of cooling fins. Additionally, each heat pipe in the first set of heat pipes includes an evaporator portion that is thermally coupled to the IC and perpendicular to the evaporator portion of the second set of heat pipes. In other embodiments, each heat pipe in the first set of heat pipes further includes at least one condenser portion that extends outward from the evaporator portion of the heat pipe and is perpendicular to the evaporator portion. In such an embodiment, the condenser portion can also be directly coupled to the plurality of cooling fins. Figures 19A - 19D One such embodiment is shown in

[0088] Figure 19AA perspective view of a heat exchanger 1900 according to various embodiments of the present invention is schematically shown, with the cooling fins and the auxiliary metal plates omitted. The heat exchanger 1900 includes a first group of heat pipes 1950 and a second group of heat pipes 1940. Each heat pipe 1950 in the first group includes an evaporator section 1951 and at least one condenser section 1952, and each heat pipe 1940 in the second group includes an evaporator section 1941 and at least one condenser section 1942.

[0089] In some embodiments, in the first group of heat pipes 1950, the evaporator section 1951 of each heat pipe 1950 is thermally coupled to a metal plate 1970 that contacts the IC, and the metal plate 1970 is in turn coupled to the IC (not shown). For example, in some embodiments, the metal plate 1970 that contacts the IC is coupled to the IC in the same manner as the metal plate 150 in FIG. 1 is coupled to the IC 101. In such embodiments, the evaporator section 1951 may be at least partially embedded within the metal plate 1970 that contacts the IC. Figure 20 One such embodiment is shown in.

[0090] Figure 20 A cross-sectional view of the evaporator section 1951 and the metal plate 1970 that contacts the IC according to an embodiment of the present invention is schematically shown. Also shown are the IC 2002 coupled to the first surface 1973 of the metal plate 1970 that contacts the IC, the evaporator section 1941 of the heat pipe 1940 coupled to the second surface opposite the first surface, portions of the condenser section 1942 of one heat pipe 1940, and an array of finned plates 2056. In Figure 20 the embodiment shown, the array of finned plates 2056 is coupled to one or more evaporator sections 1941 via an auxiliary metal plate 2057.

[0091] In this embodiment, a plurality of cavities 2001 are formed in the metal plate 1970 that contacts the IC, and each cavity is configured to receive at least a portion of an evaporator section 1951, as shown. In some embodiments, the space or air gap between the corresponding surfaces of the evaporator section 1951 and the cavity 2001 is filled with a material that facilitates heat transfer from the metal plate 1970 in contact with the IC and the evaporator section 1051, such as solder, thermal paste, etc. Additionally, in some embodiments, the metal plate 1070 further includes a cover plate 2070 that helps couple the evaporator section 1941 of the heat pipe 1940 to the metal plate 1970 in contact with the IC. In such an embodiment, the cover plate 2070 can be welded in place on the cavity 2001 and the evaporator section 1951. Additionally or alternatively, in some embodiments, the evaporator section 1941 can be welded in place on the cover plate 2070 to enhance heat transfer from the metal plate 1970 in contact with the IC to the evaporator section 1941.

[0092] Return to Figure 19A , at least one condenser section 1952 of a particular heat pipe 1950 is perpendicular to the evaporator section 1951 of that particular heat pipe 1950. That is, the condenser section 1952 of each heat pipe 1950 extends away from the metal plate 1970 (and the IC 2002, as Figure 20 shown). Additionally, at least one condenser section 1952 of each heat pipe 1950 is directly coupled to a cooling fin (not shown) of the heat exchanger 1900. For example, in some embodiments, at least one condenser section 1952 of each heat pipe 1950 is coupled to the cooling fin in the same manner as the heat pipe 140 is coupled to the cooling fin 121 in Figure 1A and Figure 1B .

[0093] Figure 19B A perspective view of a heat exchanger 1900 according to an embodiment of the present invention is schematically shown, where the cooling fins are omitted but an auxiliary metal plate 2057 is included. As shown, the auxiliary metal plate 2057 is coupled to the metal plate 1970 in contact with the IC and / or the evaporator section 1941 of the heat pipe 1940. In some embodiments, the auxiliary metal plate 2057 helps couple the cooled fin 2056 with the plate mounted to the metal plate 1970 in contact with the IC and / or the evaporator section 1941 of the heat pipe 1940. Figure 19C One such embodiment is shown in

[0094] Figure 19CA perspective view of a heat exchanger 1900 according to an embodiment of the present invention is schematically shown, in which the cooling fins are omitted, but the auxiliary metal plate 2057, the cooling fins 2056 with the plates mounted thereon, and the substrate 1975 are shown. The cooling fins 2056 with the plates mounted thereon are coupled to the auxiliary metal plate 2057 and are positioned close to the evaporator portion 1941 of the heat pipe 1940 and the metal plate 1970 in contact with the IC. Note that due to the bent portions of the evaporator portion 1941 and the evaporator portion 1951, it may be difficult to mount the cooling fins oriented parallel to the metal plate 1970 in contact with the IC close to the metal plate 1970 in contact with the IC. Therefore, the cooling fins 2056 with the plates mounted thereon contribute to heat transfer from the evaporator portion 1941 of the heat pipe 1940 and from the metal plate 1970 in contact with the IC to the cooling air flowing through the region excluding the cooling fins parallel to the metal plate 1970 in contact with the IC.

[0095] As previously described, Figure 19C An embodiment of the substrate 1975 according to some embodiments is also shown, which is configured to be coupled to the metal plate 1970 in contact with the IC. As shown, the substrate 1975 is substantially similar in configuration to Figure 10 the substrate 1050. Thus, in some embodiments, the substrate 1975 is configured to mate with the metal plate 1970 in contact with the IC, to which the heat pipes 1941 and 1951 are coupled. The substrate 1975 has a greater length 1976 and a greater width 1977 than the metal plate 1970 in contact with the IC, thus facilitating heat transfer conducted from the IC over a wider surface area than the metal plate 1970 in contact with the IC.

[0096] In some embodiments, the condenser portion 1952 of the heat pipe 1950 is disposed in the low-density heat pipe region 1953, and the condenser portion 1942 of the heat pipe 1940 is disposed in the high-density heat pipe region 1954. In such an embodiment, a portion of the metal plate 1970 in contact with the IC (which is closest to the IC 2002 and thus at the highest temperature during operation of the IC 2002) has a higher density of the heat pipe 1940 coupled thereto. In contrast, the lower temperature portion of the metal plate 1970 in contact with the IC (such as the low-density heat pipe region 1953) has a lower density of the heat pipe 1940 coupled thereto.

[0097] Figure 19D A perspective view of a heat exchanger 1900 according to an embodiment of the present invention is schematically shown, in which the cooling fins are omitted, and the IC contact surface 1971 of the metal plate 1970 in contact with the IC is shown. In Figure 19DIn the illustrated embodiment, the evaporator portion 1951 of the heat pipe 1950 is at least partially embedded or otherwise disposed within a metal plate 1970 that contacts the IC. Additionally, the evaporator portion 1941 of the heat pipe 1940 is coupled to the surface of the metal plate 1970 that contacts the IC and is opposite the IC contact surface 1971.

[0098] In summary, embodiments of the present invention provide a heat exchanger for an IC that includes an integrated heat sink and at least one low-pressure-drop air plenum formed by fins of the integrated heat sink. The low-pressure-drop air plenum is disposed proximate the IC and causes the cooling fluid flowing through the heat exchanger to have a higher velocity proximate the IC. As a result, the heat transfer capacity of the heat exchanger is increased. Thus, for a particular pressure drop of the cooling fluid flowing through the heat exchanger, the plenum formed by the fins enables more heat to be removed from the IC.

[0099] Relative to the prior art, at least one technical advantage of the disclosed heat exchanger design is that heat generated by the IC can be removed from the IC more effectively, enabling the IC to operate at a higher processing speed without overheating. Another advantage is that the pressure drop through the disclosed heat exchanger is generally less than the pressure drop through a conventional heat exchanger, which reduces fan power consumption and fan noise relative to conventional heat exchanger designs. These technical advantages provide one or more technological advancements compared to prior art methods.

[0100] 1. In some embodiments, an electronic device includes: an integrated circuit; and a heat exchanger including: at least one heat pipe thermally coupled to the integrated circuit and having an evaporator portion and a condenser portion, wherein the condenser portion extends outwardly from the evaporator portion; and a first plurality of fins attached to the condenser portion and proximate the evaporator portion and forming a plenum having a first associated pressure drop when a cooling fluid flows through the first plurality of fins at a first velocity; and a second plurality of fins attached to the condenser portion and remote from the evaporator portion and forming a flow path having a second associated pressure drop when the cooling fluid flows through the second plurality of fins at the first velocity.

[0101] 2. The electronic device of clause 1, wherein the heat exchanger further includes: a second heat pipe thermally coupled to the integrated circuit and having an evaporator portion and a condenser portion; and a third plurality of fins thermally coupled to the integrated circuit and disposed between the evaporator portion of the first heat pipe and the evaporator portion of the second heat pipe.

[0102] 3. The electronic device of clause 1 or 2, wherein the fins of the third plurality of fins extend outwardly from the integrated circuit into an airflow region that includes a bent portion of the first heat pipe and a bent portion of the second heat pipe.

[0103] 4. The electronic device according to any one of clauses 1-3, wherein the heat sink among the third plurality of heat sinks is mounted on the first side of the metal plate, and the integrated circuit is mounted on the second side of the metal plate opposite to the first side.

[0104] 5. The electronic device according to any one of clauses 1-4, wherein the evaporator portion is parallel to the first surface of the integrated circuit, and the condenser portion is perpendicular to the first surface of the integrated circuit.

[0105] 6. The electronic device according to any one of clauses 1-5, wherein the static pressure chamber is formed in the edge region of the heat exchanger.

[0106] 7. The electronic device according to any one of clauses 1-6, wherein each heat sink among the first plurality of heat sinks has a respective length in the cooling fluid flow direction that is less than the length of the heat sink among the second plurality of heat sinks in the direction of the cooling fluid.

[0107] 8. The electronic device according to any one of clauses 1-7, wherein the second pressure drop is greater than the first pressure drop.

[0108] 9. The electronic device according to any one of clauses 1-8, wherein the integrated circuit is coupled to the first side of the metal plate, and the evaporator portion is coupled to the second side of the metal plate opposite to the first side.

[0109] 10. The electronic device according to any one of clauses 1-9, wherein: the condenser portion includes a first straight section coupled to the evaporator portion via a first bent section and a second straight section coupled to the evaporator portion via a second bent section, and the heat exchanger further includes a third plurality of heat sinks that are thermally coupled to the metal plate and disposed between the first bent section and the second bent section.

[0110] 11. The electronic device according to any one of clauses 1-10, wherein the at least one heat pipe includes a heat pipe embedded in the metal plate.

[0111] 12. The electronic device according to any one of clauses 1-11, wherein the evaporator portion includes a straight section, and the heat pipe embedded in the metal plate is perpendicular to the straight section.

[0112] 13. The electronic device according to any one of clauses 1-12, wherein each heat sink among the first plurality of heat sinks is separated by a first fin pitch, each heat sink among the second plurality of heat sinks is separated by a second fin pitch, and wherein the first fin pitch is greater than the second fin pitch.

[0113] 14. The electronic device according to any one of clauses 1 - 13, wherein each of the first plurality of cooling fins has a first fin length, and each of the second plurality of cooling fins has a second fin length.

[0114] 15. The electronic device according to any one of clauses 1 - 14, wherein the first fin length is equal to the second fin length.

[0115] 16. The electronic device according to any one of clauses 1 - 15, wherein the respective lengths of the cooling fins in the first plurality of cooling fins correspond to a first termination profile, and the respective lengths of the cooling fins in the second plurality of cooling fins correspond to a second termination profile.

[0116] 17. An electronic device comprising an integrated circuit and a heat exchanger, the heat exchanger comprising: at least one heat pipe thermally coupled to the integrated circuit and having an evaporator portion and a condenser portion, wherein the condenser portion extends outwardly from the evaporator portion; a first plurality of cooling fins adjacent to the evaporation portion and forming a plenum chamber; and a second plurality of cooling fins remote from the evaporation portion and forming a flow path, wherein the plenum chamber is configured to cause a first portion of a cooling fluid to flow through the plenum chamber at a first velocity and through the flow path at a second velocity, wherein the first velocity is greater than the second velocity.

[0117] 18. The electronic device according to clause 17, wherein the plenum chamber is formed in an edge region of the heat exchanger.

[0118] 19. The electronic device according to clause 17 or 18, wherein the respective length of each of the cooling fins in the first plurality of cooling fins in the cooling fluid flow direction is less than the length of the cooling fins in the second plurality of cooling fins in the cooling fluid direction.

[0119] 20. The electronic device according to any one of clauses 17 - 19, wherein the respective lengths of the cooling fins in the first plurality of cooling fins correspond to a termination profile.

[0120] 21. In some embodiments, a heat exchanger comprising: a first heat pipe comprising a first evaporator portion and a first condenser portion, wherein the first condenser portion extends outwardly from the first evaporator portion; a second heat pipe thermally coupled to the first heat pipe and comprising a second evaporator portion and a second condenser portion; and a plurality of cooling fins, wherein each of the plurality of cooling fins is attached to the second condenser portion.

[0121] 22. The heat exchanger according to clause 21, wherein the second evaporator portion is mechanically coupled to the first heat pipe.

[0122] 23. The heat exchanger according to clause 21 or 22 further includes a metal plate having a first surface coupled to the first heat pipe.

[0123] 24. The heat exchanger according to any one of clauses 21 - 23 further includes an integrated circuit coupled to a second surface of the metal plate, wherein the second surface of the metal plate is opposite to the first surface of the metal plate.

[0124] 25. The heat exchanger according to any one of clauses 21 - 24, wherein the first surface is directly coupled to the first evaporator portion.

[0125] 26. The heat exchanger according to any one of clauses 21 - 25, wherein the first heat pipe is included in a plurality of heat pipes directly coupled to the first surface of the metal plate.

[0126] 27. The heat exchanger according to any one of clauses 21 - 26, wherein the first heat pipe is at least partially disposed within the metal plate.

[0127] 28. The heat exchanger according to any one of clauses 21 - 27, wherein the plurality of cooling fins includes: a first group of cooling fins near the second evaporation portion and forming a static pressure chamber; and a second group of cooling fins away from the second evaporation portion and forming a flow path.

[0128] 29. The heat exchanger according to any one of clauses 21 - 28, wherein when the cooling fluid flows through the first group of cooling fins at a first velocity, the static pressure chamber has a first associated pressure drop, and when the cooling fluid flows through the second group of cooling fins at the first velocity, the flow path has a second associated pressure drop.

[0129] 30. The heat exchanger according to any one of clauses 21 - 29, wherein the second evaporator portion is perpendicular to the second condenser portion.

[0130] 31. The heat exchanger according to any one of clauses 21 - 30, wherein the second heat pipe is included in a plurality of heat pipes, and each heat pipe in the plurality of heat pipes has an evaporator portion and a condenser portion perpendicular to the evaporator portion.

[0131] 32. The heat exchanger according to any one of clauses 21 - 31, wherein the first evaporator portion is perpendicular to the first condenser portion.

[0132] 33. The heat exchanger according to any one of clauses 21 - 32, wherein the second evaporator portion is perpendicular to the second condenser portion, and the first condenser is parallel to the second condenser portion.

[0133] 34. The heat exchanger according to any one of clauses 21 - 33, wherein each of the plurality of cooling fins is attached to the first condenser portion.

[0134] 35. In some embodiments, an electronic device includes a first integrated circuit thermally coupled to a first heat exchanger, the first heat exchanger including: a first heat pipe including a first evaporator portion and a first condenser portion, wherein the first condenser portion extends outwardly from the first evaporator portion; a second heat pipe thermally coupled to the first heat pipe and including a second evaporator portion and a second condenser portion; and a plurality of cooling fins, wherein each of the plurality of cooling fins is attached to the second condenser portion.

[0135] 36. The electronic device according to clause 35, wherein the second evaporator portion is mechanically coupled to the first heat pipe.

[0136] 37. The electronic device according to clause 35 or 36, further including a metal plate having a first surface coupled to the first heat pipe.

[0137] 38. The electronic device according to any one of clauses 35 - 37, further including: a printed circuit board on which the first integrated circuit is mounted; a second integrated circuit mounted on the printed circuit board; and a second heat exchanger thermally coupled to the second integrated circuit.

[0138] 39. The electronic device according to any one of clauses 35 - 38, wherein the first heat exchanger and the second heat exchanger are positioned on the printed circuit board to allow a cooling fluid to flow through the first heat exchanger first and then through the second heat exchanger.

[0139] 40. The electronic device according to any one of clauses 35 - 39, wherein: the first heat exchanger includes a first plurality of cooling fins; and the second heat exchanger includes a second plurality of cooling fins arranged parallel to the first plurality of cooling fins.

[0140] 41. The electronic device according to any one of clauses 35 - 40, wherein: the first heat pipe is included in a first plurality of heat pipes, wherein each heat pipe included in the first plurality of heat pipes has a third condenser portion; the second heat pipe is included in a second plurality of heat pipes, wherein each heat pipe included in the second plurality of heat pipes has a fourth condenser portion; and the third condenser portions are arranged in the first heat exchanger at a first density, and the second condenser portions are arranged in the first heat exchanger at a second density less than the first density.

[0141] Any and all combinations of any claim elements recited in any claim and / or any elements described in this application, in any way, fall within the intended scope of the present invention and protection.

[0142] The description of the various embodiments is presented for illustrative purposes but is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

[0143] Although the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope of the present invention, and the scope of the present invention is determined by the appended claims.

Claims

1. An electronic device, comprising: an integrated circuit; and a heat exchanger, comprising: a plurality of heat pipes thermally coupled to the integrated circuit, wherein each heat pipe included in the plurality of heat pipes has an evaporator portion and a condenser portion, and wherein the condenser portion extends outwardly from the evaporator portion; a first plurality of cooling fins attached to a first heat pipe included in the plurality of heat pipes but not attached to a second heat pipe included in the plurality of heat pipes, wherein the first plurality of cooling fins are attached to the bottom of the condenser portion near the evaporator portion of the first heat pipe; wherein the respective lengths of the cooling fins in the first plurality of cooling fins correspond to at least one of a termination profile associated with a parabolic function or a termination profile associated with a linear function that is close to a minimum of the termination profile of the final cooling fin in the first plurality of cooling fins closest to the integrated circuit; and a second plurality of cooling fins attached to each heat pipe included in the plurality of heat pipes, wherein the second plurality of cooling fins are attached to the top of the condenser portion that is the most distal from the evaporator portion of each heat pipe included in the plurality of heat pipes, and wherein the top of the condenser portion of each heat pipe included in the plurality of heat pipes is not attached to any cooling fin that is attached to the first heat pipe but not attached to the second heat pipe.

2. The electronic device according to claim 1, wherein the heat exchanger further comprises: a third heat pipe thermally coupled to the integrated circuit and having an evaporator portion and a condenser portion; and a third plurality of cooling fins thermally coupled to the integrated circuit and disposed between the evaporator portion of a fourth heat pipe and the evaporator portion of the third heat pipe.

3. The electronic device according to claim 2, wherein the cooling fins in the third plurality of cooling fins extend outwardly from the integrated circuit into an airflow region that includes a bent portion of the fourth heat pipe and a bent portion of the third heat pipe.

4. The electronic device according to claim 2, wherein the cooling fins in the third plurality of cooling fins are mounted on a first side of a metal plate, and the integrated circuit is mounted on a second side of the metal plate opposite to the first side.

5. The electronic device according to claim 1, wherein the evaporator portion of each heat pipe included in the plurality of heat pipes is parallel to a first surface of the integrated circuit, and the condenser portion of each heat pipe included in the plurality of heat pipes is perpendicular to the first surface of the integrated circuit.

6. The electronic device according to claim 1, wherein the first plurality of cooling fins form a static pressure chamber in an edge region of the heat exchanger.

7. The electronic device according to claim 1, wherein the respective length of each cooling fin in the first plurality of cooling fins in the direction of cooling fluid flow is less than the length of the cooling fins in the second plurality of cooling fins in the direction of cooling fluid flow.

8. The electronic device according to claim 1, wherein the first plurality of cooling fins form a static pressure chamber, and the second plurality of cooling fins form a flow path, wherein when the cooling fluid flows through the first plurality of cooling fins at a first velocity, the static pressure chamber has a first associated pressure drop, and when the cooling fluid flows through the second plurality of cooling fins at a second velocity, the flow path has a second associated pressure drop, and the second associated pressure drop is greater than the first associated pressure drop.

9. The electronic device according to claim 1, wherein the integrated circuit is coupled to a first side of the metal plate, and the evaporator portion of each heat pipe included in the plurality of heat pipes is coupled to a second side of the metal plate opposite the first side.

10. The electronic device according to claim 9, wherein: for each heat pipe included in the plurality of heat pipes, the condenser portion includes a first straight section coupled to the evaporator portion via a first bending section and a second straight section coupled to the evaporator portion via a second bending section, and the heat exchanger further includes a third plurality of cooling fins thermally coupled to the metal plate and disposed between the first bending section and the second bending section.

11. The electronic device according to claim 9, wherein the plurality of heat pipes includes heat pipes embedded in the metal plate.

12. The electronic device according to claim 11, wherein the evaporator portion of each heat pipe included in the plurality of heat pipes includes a straight section, and the heat pipe embedded in the metal plate is perpendicular to the straight section.

13. The electronic device according to claim 1, wherein each of the first plurality of cooling fins is spaced apart by a first fin spacing, and each of the second plurality of cooling fins is spaced apart by a second fin spacing, and wherein the first fin spacing is greater than the second fin spacing.

14. The electronic device according to claim 13, wherein the length of each of the first plurality of cooling fins in the cooling fluid flow direction is less than the length of the cooling fins in the second plurality of cooling fins in the cooling fluid flow direction.

15. The electronic device according to claim 1, wherein the respective lengths of the cooling fins in the first plurality of cooling fins correspond to a first termination profile, and the respective lengths of the cooling fins in the second plurality of cooling fins correspond to a second termination profile.

16. An electronic device, comprising an integrated circuit and a heat exchanger, the heat exchanger comprising: a plurality of heat pipes thermally coupled to the integrated circuit, wherein each heat pipe included in the plurality of heat pipes has an evaporator portion and a condenser portion, and wherein the condenser portion extends outward from the evaporator portion; A first plurality of cooling fins, which are attached to a first heat pipe included in the plurality of heat pipes but not attached to a second heat pipe included in the plurality of heat pipes, wherein the first plurality of cooling fins are attached to a bottom of the evaporator portion of the condenser portion that is close to the first heat pipe; wherein respective lengths of the cooling fins in the first plurality of cooling fins correspond to at least one of termination profiles associated with a parabolic function or at least one of termination profiles associated with a linear function that is close to a minimum value of a termination profile of the final cooling fin in the first plurality of cooling fins closest to the integrated circuit; and A second plurality of cooling fins, which are attached to each heat pipe included in the plurality of heat pipes, wherein the second plurality of cooling fins are attached to a top of the condenser portion that is the most distal from the evaporator portion of each heat pipe included in the plurality of heat pipes, and wherein the top of the condenser portion of each heat pipe included in the plurality of heat pipes is not attached to any cooling fin that is attached to the first heat pipe but not attached to the second heat pipe.

17. The electronic device according to claim 16, wherein the first plurality of cooling fins form a static pressure chamber in an edge region of the heat exchanger.

18. The electronic device according to claim 16, wherein respective lengths of each of the cooling fins in the first plurality of cooling fins in a flow direction of the cooling fluid are less than lengths of the cooling fins in the second plurality of cooling fins in the flow direction of the cooling fluid.

19. The electronic device according to claim 18, wherein respective lengths of the cooling fins in the first plurality of cooling fins correspond to termination profiles.

20. A heat exchanger, comprising: A first heat pipe, which includes a first evaporator portion and a first condenser portion, wherein the first condenser portion extends outward from the first evaporator portion; A second heat pipe, which is thermally coupled to the first heat pipe and includes a second evaporator portion and a second condenser portion; A first plurality of cooling fins, which are attached to a first bottom of the first condenser portion that is close to the first evaporator portion of the first heat pipe, and wherein the first plurality of cooling fins are not attached to the second heat pipe; wherein respective lengths of the cooling fins in the first plurality of cooling fins correspond to at least one of termination profiles associated with a parabolic function or at least one of termination profiles associated with a linear function that is close to a minimum value of a termination profile of the final cooling fin in the first plurality of cooling fins closest to the integrated circuit; and A second plurality of cooling fins, which are attached to a first top of the first condenser portion that is the most distal from the first evaporator portion of the first heat pipe, and the second plurality of cooling fins are attached to a second top of the second condenser portion that is the most distal from the second evaporator portion of the second heat pipe, wherein the first top of the first condenser portion of the first heat pipe is not attached to any cooling fin that is attached to the first heat pipe but not attached to the second heat pipe, and the second top of the second condenser portion of the second heat pipe is not attached to any cooling fin that is attached to the first heat pipe but not attached to the second heat pipe.

21. The heat exchanger according to claim 20, wherein the second evaporator portion is mechanically coupled to the first heat pipe.

22. The heat exchanger according to claim 20, further comprising a metal plate having a first surface coupled to the first heat pipe.

23. The heat exchanger according to claim 22, further comprising an integrated circuit coupled to a second surface of the metal plate, wherein the second surface of the metal plate is opposite the first surface of the metal plate.

24. The heat exchanger according to claim 22, wherein the first surface is directly coupled to the first evaporator portion.

25. The heat exchanger according to claim 24, wherein the first heat pipe is included in a plurality of heat pipes directly coupled to the first surface of the metal plate.

26. The heat exchanger according to claim 22, wherein the first heat pipe is at least partially disposed within the metal plate.

27. The heat exchanger according to claim 20, wherein the first plurality of cooling fins are adjacent to the second evaporation portion, the second plurality of cooling fins are remote from the second evaporation portion.

28. The heat exchanger according to claim 20, wherein the first plurality of cooling fins form a static pressure chamber and the second plurality of cooling fins form a flow path, wherein the static pressure chamber is configured to allow a cooling fluid to flow through the static pressure chamber at a first velocity and through the flow path at a second velocity, and when the cooling fluid flows through the first plurality of cooling fins at the first velocity, the static pressure chamber has a first associated pressure drop, and when the cooling fluid flows through the second plurality of cooling fins at the second velocity, the flow path has a second associated pressure drop.

29. The heat exchanger according to claim 20, wherein the second evaporator portion is perpendicular to the second condenser portion.

30. The heat exchanger according to claim 29, wherein the second heat pipe is included in a plurality of heat pipes, and each heat pipe in the plurality of heat pipes has an evaporator portion and a condenser portion perpendicular to the evaporator portion.

31. The heat exchanger according to claim 20, wherein the first evaporator portion is perpendicular to the first condenser portion.

32. The heat exchanger according to claim 31, wherein the second evaporator portion is perpendicular to the second condenser portion, and the first condenser is parallel to the second condenser portion.

33. An electronic device comprising a first integrated circuit thermally coupled to a first heat exchanger, the first heat exchanger comprising: a first heat pipe including a first evaporator portion and a first condenser portion, wherein the first condenser portion extends outwardly from the first evaporator portion; a second heat pipe thermally coupled to the first heat pipe and including a second evaporator portion and a second condenser portion; A first plurality of cooling fins, which are attached to a first bottom of the first condenser portion near the first evaporator portion of the first heat pipe, wherein the first plurality of cooling fins are not attached to the second heat pipe; wherein respective lengths of the cooling fins in the first plurality of cooling fins correspond to at least one of termination profiles associated with a parabolic function or at least one of termination profiles associated with a linear function that is close to a minimum value of a final cooling fin in the first plurality of cooling fins closest to the integrated circuit. and A second plurality of cooling fins, which are attached to a first top of the first condenser portion at a most distal end of the first evaporator portion of the first heat pipe, the second plurality of cooling fins are attached to a second top of a second condenser portion at a most distal end of the second evaporation portion of the second heat pipe, wherein the first top of the first condenser portion of the first heat pipe is not attached to any cooling fins that are attached to the first heat pipe but not to the second heat pipe, and the second top of the second condenser portion of the second heat pipe is not attached to any cooling fins that are attached to the first heat pipe but not to the second heat pipe.

34. The electronic device according to claim 33, wherein the second evaporator portion is mechanically coupled to the first heat pipe.

35. The electronic device according to claim 33, further comprising a metal plate having a first surface coupled to the first heat pipe.

36. The electronic device according to claim 33, further comprising: a printed circuit board on which the first integrated circuit is mounted; a second integrated circuit, which is mounted on the printed circuit board; and a second heat exchanger, which is thermally coupled to the second integrated circuit.

37. The electronic device according to claim 36, wherein the first heat exchanger and the second heat exchanger are positioned on the printed circuit board to allow a cooling fluid to flow through the first heat exchanger first and then through the second heat exchanger.

38. The electronic device according to claim 37, wherein: the second heat exchanger includes a third plurality of cooling fins arranged in parallel with the first plurality of cooling fins.

39. The electronic device according to claim 33, wherein: the first heat pipe is included in a first plurality of heat pipes, wherein each heat pipe included in the first plurality of heat pipes has a third condenser portion; the second heat pipe is included in a second plurality of heat pipes, wherein each heat pipe included in the second plurality of heat pipes has a fourth condenser portion; and the third condenser portion is arranged in the first heat exchanger at a first density, and the second condenser portion is arranged in the first heat exchanger at a second density less than the first density.

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