TEMPERATURE CONTROL OF DENSIVELY PACKED ELECTRONIC ASSEMBLIES

Abstract

A thin, single-layer, thermally conductive jacket surrounds a PCA. One or more springs integrated into the jacket apply a compressive force to the PCA components when cooling is desired. This compressive force establishes and maintains thermal contact, conducting heat from the PCA components into the jacket. The jacket conducts heat (either directly or indirectly) to a liquid-cooled cold plate configured as a cold frame that surrounds one or more of the jacketed PCAs. The jacket transfers heat from the PCA components to the cold frame, possibly via intervening heat transfer devices such as heat spreaders or heat pipes. The fluid flowing through the cold frame's internal channels convects heat out of the electronic device.Turbulence, promoted by turbulence-enhancing artifacts such as curvatures and shape changes along the internal channels, increases the efficiency of convection.

Description

BACKGROUND

[0001] Many electronic components are designed to operate within a temperature range defined by a temperature specification. In particular, the operating temperature affects the functionality and efficiency of computers. Excessive heat often degrades the real-time performance of electronic components. Furthermore, component materials can fatigue over time, which in turn can shorten the lifespan of the hardware. For large or powerful computing devices, which may contain a high density of heat-generating electronic components, heat dissipation and cooling of these electronic components are therefore a key focus. As technology advances, more and more electronic devices are being deployed in ever greater numbers and at ever greater densities.This type of implementation can generally exacerbate concerns (and difficulties) regarding maintaining operating temperatures within the specified range.

[0002] US 2013 / 0 194 745 A1 describes that each pair of memory modules in a storage system is cooled using a common cooling conduit, for example, a heat conduit or a liquid conduit. An exemplary embodiment of US 2013 / 0 194 745 A1 includes a pair of memory module sockets on opposite sides of the respective cooling tube. An inner heat spreader plate is thermally coupled to the cooling tube and in thermal contact with a first surface of the memory module adjacent to the contained cooling tube. Heat is conducted from the second surface of the memory module to the cooling tube, for example, from an outer plate in thermal contact with an opposite second surface of the memory modules and with the inner plate.

[0003] DE 11 2009 004 714 T5 describes a cooling device comprising: a main printed circuit board having a top surface; a plurality of connectors mounted on the top surface of the main printed circuit board in parallel rows; a first liquid cooling manifold positioned along a first end of the parallel rows of connectors; a second liquid cooling manifold positioned along a second end of the parallel rows of connectors;a plurality of heat sinks, each having an elongated shape, the heat sinks extending parallel to the connectors such that a connector is disposed between two heat sinks, the plurality of heat sinks each having a first end and a second end, the first end coupled to the first liquid cooling manifold and the second end coupled to the second liquid cooling manifold; a component assembly inserted into a first of the plurality of connectors, the component assembly comprising: a printed circuit board, at least one component mounted on a front side of the printed circuit board;a first heat spreader comprising a plate with a bottom surface and a front surface, the front surface being held against a top surface of the at least one component mounted on the front surface of the printed component circuit board; a plurality of protrusions spaced along the bottom surface of the first heat spreader such that the protrusions contact a top surface of one of the plurality of heat dissipation devices when the printed component circuit board is inserted into one of the plurality of connectors; a second heat spreader mounted against the printed component circuit board on the opposite side of the first heat spreader, the second heat spreader comprising a plate with a bottom surface and a front surface;a plurality of protrusions formed along the bottom surface of the second heat spreader, the protrusions being spaced apart by gaps having a gap length slightly greater than a length of the protrusions, and the protrusions on the second heat spreader being offset from the protrusions on the first heat spreader such that the protrusions on the second heat spreader fit between protrusions on a first heat spreader of a second component assembly when the second component assembly is inserted into a second one of the plurality of connectors adjacent to the first one of the plurality of connectors, such that both the first heat spreader of the second component assembly and the second heat spreader contact a top surface of one of the plurality of heat dissipators;

[0004] US 7,675,748 B2 describes a disk array system comprising a plurality of disk drives and at least one housing unit with the plurality of disk drives aligned in the thickness direction of the disk drive. Each disk drive comprises a thin housing in which a recording disk, a read / write head, and a drive mechanism for driving the recording disk and the read / write head are located, as well as a control board for controlling the drive mechanism, the control board being mounted on the thin housing. In the disk array system, the thin housing and the unit box are made of a heat-conducting material, the unit box has surfaces that run parallel to the thickness direction of the plurality of disk drives, and at least one of the surfaces has a cooling plate filled with a coolant. The heat generated by the hard disks is transferred to the cooling plate, thereby improving cooling performance.

[0005] US 10 602 640 B1 describes a memory cooler comprising a housing. The housing consists of two parts that are movable relative to each other. Each part of the housing includes an inlet manifold, an outlet manifold, and a plurality of cooling plates extending between the inlet manifold and the outlet manifold. The inlet manifold serves to receive liquid coolant from a coolant supply line. The outlet manifold serves to return the liquid coolant to the coolant supply line. The liquid coolant flows through the internal channels of the cooling plates from the inlet manifold to the outlet manifold. The plurality of cooling plates of a first part of the housing are nested with the plurality of cooling plates of a second part of the housing such that slots for receiving memory modules are defined between adjacent pairs of cooling plates.

[0006] US 2010 / 0 091 447 A1 describes a device comprising a first thermal interface material and a first microchannel cooling plate. The first thermal interface material is in physical communication with a first plurality of memory modules of a computer system. The first microchannel cooling plate is in physical communication with the first thermal interface material. The first microchannel cooling plate is adapted to enable fluid flow through a first plurality of microchannels and is configured to dissipate a first amount of heat generated by the first memory modules of the computer system through the first thermal interface material. SHORT DESCRIPTION

[0007] A heat transfer assembly according to claims 1 to 8, a computer subassembly according to claims 9 to 17 and a computer system according to claims 18 to 20 are disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present technique will be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals designate like elements and in which: Fig. is an exploded perspective view of a liquid cooling system for a printed circuit assembly. Fig. is a schematic representation of the system of Fig. used heat dissipation mechanisms in a partial cross-section along the line 2-2 in Fig. . Fig. is a sectional end view of a printed circuit assembly and a first circuit board taken along line 3-3 in Fig. and shows the mechanical clearances for components that determine the thickness constraints for the PCA jacket. Fig. is a perspective assembly view of a jacketed PCA with a single-layer heat transfer jacket that Fig. specified thickness restrictions are met. Fig. is an end view of a pair of PCAs in heat transfer jackets as in Fig. that are installed in adjacent electronic sockets of a host board. Fig. is an end view of a possible implementation of thermal devices, shown as an example with respect to a cross section such as line AA in Fig. from several very closely spaced jacketed PCAs that dissipate heat through the heat transfer jackets of adjacent jacketed PCAs. Fig. is an end view of a second possible implementation of thermal devices, shown as an example with respect to a cross section such as line AA in Fig. a higher performance jacketed PCA to transfer heat to external heat transfer devices. Fig. is an end view of a third possible implementation of thermal devices, shown as an example with respect to a cross section such as line AA in Fig. a high-performance PCA with high components to transfer heat to a heat spreader with uneven thickness. Fig. is a side view of the areas of thermal contact between the heat transfer jacket of Fig. and the underlying PCA components. Fig. is a side view of the areas of thermal contact between the heat transfer jacket of Fig. and the external heat spreader or the adjacent jacket. Fig. is a perspective, enlarged view of a portion of the lower edge of a cover portion of a heat transfer sleeve as shown in Fig. depicted with live feathers that are shown as captive at both ends. Fig. is a perspective, enlarged view of a portion of a lower edge of a cover portion of a heat transfer sleeve as shown in Fig. which is formed with live feathers, which are initially free at the lower end and then secured by tucking into a hem fold. Fig. is a perspective, enlarged view of a Fig. cooling frame shown with details of the modified channel shape and bends that improve turbulence and increase cooling efficiency. Fig. illustrate selected features of bends and cross-sections of the coolant channel. Fig. is a perspective sectional view of an example of a turbulence enhancing end block channel in the cooling frame of Fig. . Fig. is a perspective sectional view of another example of a turbulence enhancing end block channel in the cooling frame of Fig. . Fig. is a side view of a contact area between a shroud or heat spreader and a cooling frame slot when the channel has an L-bend but no U-bend or shape change. Fig. is a sectional side view of a contact surface between a shell or heat spreader and a cooling frame slot when the channel undergoes an L-bend, a U-bend, and a shape change. Fig. is a perspective view (with an overlaid flow diagram) of a duplicate version of the cooling frame of Fig. capable of cooling two banks of closely spaced PCAs. Fig. is a top view of a host board for a computer system with PCA socket banks equipped with the dual cooling frame of Fig. are compatible. Fig. is a top view of a cooling frame and jacket for a single high-performance PCA. Fig. is a top view of the assembly of a cooling frame for a bank of moderately powerful, closely spaced, shrouded PCAs without heat transfer devices. Fig. is a top view of the assembly of a cooling frame and shrouds for a row of lower power PCAs placed very close together. Fig. is a side view of the heat transfer device of Fig. . Fig. is a sectional view (through section DD of Fig. an example of a heat transfer device that is a solid heat spreader. Fig. is a sectional view (through section DD of Fig. an example of a heat transfer device that is a hollow heat spreader. Fig. is a sectional view (through section DD of Fig. an example of a heat transfer device that is a vapor chamber heat spreader. Fig. are data diagrams of thermal model results for the cooling system of Fig. with the three alternative heat transfer devices of the Fig. in a specific example.

[0009] While the technology disclosed herein is susceptible to various modifications and alternative forms, the drawings illustrate specific examples, which are described in detail herein. It should be understood, however, that the description of specific examples is not intended to limit the disclosed technology to the particular forms, but rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims. DETAILED DESCRIPTION

[0010] Examples of the claimed subject matter are disclosed below. In the interest of clarity, this specification does not describe all features of an actual implementation. In developing such a concrete implementation, numerous implementation-specific decisions may be made to achieve the developers' specific goals, such as adhering to system-related and business-related constraints that will vary from one implementation to another. Furthermore, it is recognized that such a development effort, while complex and time-consuming, is a routine undertaking for those skilled in the art having the benefit of this disclosure.

[0011] As used herein, the article "a" is intended to have its ordinary meaning in patent law, namely "one or more." When the term "about" is applied to a value, it generally means within the tolerance range of the equipment used to produce the value, or in some examples, it means plus or minus 10%, or plus or minus 5%, or plus or minus 1%, unless expressly stated otherwise. Further, the term "substantially," as used herein, means the majority or almost all or all of it, or an amount having a range of, for example, about 51% to about 100%. Furthermore, the examples herein are intended to be illustrative only and are presented for discussion purposes and not by way of limitation.

[0012] Market demand is driving the development of electronic devices with ever more features and smaller sizes. The increased capabilities can be achieved by integrated circuits ("ICs") that consume more power than previous ICs, allowing them to perform more high-speed functions simultaneously. The smaller size can be achieved by packing multiple ICs more closely together on printed circuit assemblies ("PCAs") and by placing adjacent PCAs closer together in device packages or enclosures. This reduction in size and closer alignment are both examples of increased component density. As a result of the higher power consumption and tighter spacing, more heat is likely to be generated during operation.

[0013] Heat can be removed from an undesired location by conduction through a solid or fluid, by convection through a fluid (i.e., a liquid or gas), or by thermal radiation. Alternatively, heat can be absorbed through endothermic chemical reactions such as certain phase changes. Many approaches to cooling and heat dissipation for computer systems have been and are being developed using these principles (either individually or in concert with each other).

[0014] Generally, dissipation devices for problematic heat concentrations require at least some space. Space is becoming increasingly scarce in today's computer systems (e.g., due to the general increase in component density mentioned above). In addition to the total amount of available space around the PCAs, the location and shape of that space can also be challenging. A large portion of the PCA area not occupied by ICs or other electrical components can be reserved as one or more "blocking areas." Generally, the cutouts can accommodate fasteners, chassis stiffening features, routing card cables, movement areas for moving parts, clearance for test probes, and other design objectives that may compete for space with temperature control measures.As electronic devices change, previous approaches to temperature control may become ineffective or obsolete, requiring new advances in this area.

[0015] This disclosure describes examples of cooling systems that combine solid-state conduction with liquid convection to cool closely spaced components (ICs and other parts such as inductors) mounted on PCAs, which may themselves be arranged in high-density arrays. In some examples, a thin, single-layer, thermally conductive jacket surrounds each PCA. One or more live springs may be partially integrated into the jacket to apply a compressive force to the PCA components when cooling is desired. The compressive force can establish and maintain thermal contact, allowing heat to be conducted from the PCA components into the jacket. The jacket can then conduct the heat (either directly or indirectly) to a liquid-cooled cold plate configured as a cooling frame. In some examples, this cooling frame surrounds one or more of the jacketed PCAs.

[0016] The shroud can then transfer heat from the PCA components to the cooling frame, optionally via intermediate heat transfer devices such as heat spreaders or heat pipes. A fluid flowing through the internal channels of the cooling frame can then assist in dissipating heat from the electronic device. In some systems, the coolant can flow with minimal turbulence in the fluid. However, in disclosed implementations, turbulence can be promoted or enhanced through the use of "turbulence-enhancing artifacts." Turbulence-enhancing artifacts, referred to here, are "intentionally designed" bends and shape changes along the internal channels. This increased turbulence has been shown to improve convection efficiency.

[0017] In some examples, a heat transfer assembly includes a heat transfer jacket and a cooling frame to which the heat transfer jacket is mechanically engaged and thermally coupled. The cooling frame defines an interior framed space within which at least a portion of the heat transfer jacket is disposed. The framed interior space may also define a coolant channel containing turbulence-enhancing artifacts to intentionally introduce turbulence into a fluid flow through the coolant channel.

[0018] In other examples, a computer subassembly includes a printed circuit assembly and a heat transfer assembly. The printed circuit assembly includes a printed circuit board and a plurality of electronic components mounted on the printed circuit board. The heat transfer assembly includes a heat transfer jacket and a cooling frame. The heat transfer jacket encloses the printed circuit assembly, mechanically engages it, and is thermally connected to the printed circuit assembly. The heat transfer jacket is also mechanically connected to the cooling frame. The cooling frame is also thermally connected to the heat transfer jacket and the printed circuit assembly.The cooling frame further defines an inner framed space in which at least a portion of the heat transfer jacket is disposed, and a coolant channel having turbulence-enhancing artifacts designed to intentionally introduce turbulence into a fluid flow through the coolant channel.

[0019] In still other examples, a computer system includes a first printed circuit board and a computer subassembly. The computer subassembly includes a cooling frame attached to the first printed circuit board. The cooling frame defines an inner framed space and a coolant channel with turbulence-enhancing artifacts to intentionally introduce turbulence into a fluid flow through the coolant channel. The computer subassembly also includes a plurality of encased printed circuit boards. Each encased printed circuit board is at least partially disposed within the inner framed space; it is mechanically and electrically connected to the first printed circuit board within the inner framed space; and it is thermally coupled to the coolant channel.

[0020] Fig. is an exploded perspective view of a liquid cooling system for a printed circuit assembly ("PCA") in conjunction with a portion of a computer system 100. The computer system 100 may itself be a computer or a portion of a computer. As used herein, a "computer" is any electronic device that includes a processor and is capable of executing programs with machine-readable instructions, such as a server, a converged (or hyperconverged) appliance, a rack system, some storage arrays, etc.

[0021] The computer system 100 includes a first printed circuit board (“PCB”) 101 and at least one electronic socket 102 (preferably in Fig. shown), the function of which is explained further below. The computer system 100 also includes a computer subassembly consisting of a cooling frame 140 and one or more encapsulated printed circuit boards (PCAs) 105. In the example shown, a encapsulated PCA 105 is shown in an exploded view, itself disassembled from the rest of the computer system 100. Additional encapsulated PCAs 105 (not shown separately) are installed in the computer system 100.

[0022] Those skilled in the art familiar with this disclosure will understand that computer system 100 may include many other components and features than those shown herein. For example, computer system 100 may include a power supply subsystem for powering, a cooling subsystem that supplies and receives coolant, and processor-based controls for various purposes, and / or other components. These other components and features are omitted for clarity so as not to obscure the subject matter claimed below.

[0023] The encapsulated PCA 105 includes a PCA 110 consisting of a second circuit board 111 on which a plurality of electronic components 112, 113 are mounted. In the illustrated example, the PCA 110 is a memory board, and the electronic components 112, 113 are memory modules and capacitors, respectively. In particular, the memory modules 112 are dual in-line memory modules ("DIMMs"). In other examples, the memory modules may be a type of memory module other than a DIMM. The PCA 110 may include other types of electronic components in addition to, or in place of, the memory modules 112 and the capacitors 113.

[0024] For example, the PCA 110 may also include inductors (not shown), voltage regulators (also not shown), controllers (also not shown), and the like. In some examples, the PCA 110 may be a processor board. In these examples, the electronic components may be processors or other types of electronic components used to implement the functionality of the processor board. Some examples where a plurality of packaged PCAs 105 are used may include packaged PCAs 105 where the individual PCAs 110 perform different functions. In such an example, one or more of the packaged PCAs 105 may include a PCA 110 that is a memory board, and one or more of the packaged PCAs 105 may include a PCA 110 that is a processor board.

[0025] The jacketed PCA 105 also includes a heat transfer jacket, which in the illustrated example consists of a first cover 121 and a second cover 122. The first cover 121 and the second cover 122 each contain a plurality of live springs 123, the shape and function of which are described below with respect to the Fig. 4A-6B. In the illustrated example, the first cover 121 and the second cover 122 are each formed from a single layer of material with a thermal conductivity of at least 350 W / m / K and a thickness of at most 0.25 mm. However, in other examples, more than one layer of material may be used, provided the spacing requirements are met, as well as materials with different thermal conductivities and different thicknesses.

[0026] The first cover 121 and the second cover 122 oppose each other and mechanically interlock in a manner described in more detail below to enclose the PCA 110. The first cover 121 then covers at least a first portion of a first side of the PCA 110, and the second cover 122 covers at least a second portion of the second side of the PCA 110. When the PCA 110 is encased, the heat transfer jacket mechanically engages and thermally bonds with the PCA 110.

[0027] For the purposes of this article, "thermal coupling" of two objects means that a thermally conductive path exists between the objects, allowing heat to be transferred between them. Two objects can be considered thermally coupled if one of the following conditions is met: (1) the two objects are in contact with each other (either directly or through a thermal interface material ("TIM")), (2) the objects are both thermally coupled with a heat transfer device (or a chain of thermally coupled heat transfer devices), or (3) the heat transfer coefficient between the two objects is 10 W m-2 K-1 or greater.A TIM can be a relatively thin, thermally conductive, and compliant (easily deformable) material applied between two devices at their thermal interface to improve heat transfer rates by filling air gaps that would otherwise occur due to surface roughness and / or misalignment between the devices. Common examples of TIMs include thermal pads, thermal grease, and thermal paste.

[0028] The example in Fig. also includes a pair of optional heat transfer devices 130. The heat transfer devices 130, when used, assist in the transfer of heat from the jacketed PCA 105 to the cooling frame 140. Further details regarding the heat transfer devices 130 are provided below with respect to the Fig. In the illustrated example, the heat transfer device 130 is a heat spreader, but other types of heat transfer devices may be used in other examples. In some examples, the heat transfer devices may be omitted entirely. Several such examples are discussed below.

[0029] As described in more detail below, the heat transfer devices 130 are thermally coupled and mechanically connected to the jacketed PCA 105 without being mechanically attached or otherwise fixed to the jacketed PCA 105. The cooling frame 140 defines corresponding mounting slots for the heat transfer devices 130 and the jacketed PCA 105 in examples where heat transfer devices 130 are used, although in Fig. is not shown. However, this will be Fig. shown and discussed in context.

[0030] A "heat transfer device" can be any device that is thermally conductive and configured to absorb heat from one solid body by conduction (contact) and transfer the heat to a second solid body by conduction (contact). Examples of heat transfer devices include heat pipes, vapor chambers, heat spreaders (such as solid rods or metal strips), cooling tubes, etc. A "heat pipe" refers to a specific type of heat transfer device that includes a housing (vessel) with walls surrounding a sealed internal channel containing a working fluid and a wick, such that the fluid transfers heat between different regions of the device through a cycle of evaporation and condensation.

[0031] Back to Fig. : The computer system 100 also includes the cooling frame 140. The cooling frame 140 is mechanically connected to the first circuit board 101. The first circuit board 101 may be referred to as a "host board" in the sense that it "houses" the encapsulated PCAs 105. The mechanical connection of the cooling frame 140 to the first circuit board 101 may be implemented using any suitable technique known in the art. In some examples, the cooling frame 140 may be attached to the first circuit board 101 using fasteners (not shown) such as screws. In other examples, the cooling frame 140 may be attached to the first circuit board 101 by gluing or adhering. Still other examples may use different techniques.

[0032] The cooling frame 140 defines at least one PCA slot 120 and an inner frame space 141. The inner frame space 141 is generally rectangular in the illustrated example, as is the cooling frame 140. In other examples not shown, different geometries may be used for the outer contour of the cooling frame 140 and the inner frame space 141. Likewise, in some examples, the geometry of the outer contours of the cooling frame 140 may differ from that of the inner frame space 141. The inner frame space 141 encloses the electronic sockets 102 on the first printed circuit board 101. The electronic sockets 102 are part of the PCA slots 120, as explained further below, and the shrouded PCAs 105 are aligned with the electronic sockets 102 in the PCA slots 120.

[0033] The cooling frame 140 also defines a coolant channel with turbulence-enhancing artifacts that intentionally introduce turbulence into a fluid flow through the coolant channel. The coolant channel is in Fig. not shown and is discussed below in relation to Fig. , Fig. and Fig. . In the example of Fig. There is a first fitting 142 and a second fitting 147 through which liquid coolant enters and exits the coolant channel, respectively. In the illustrated example, the first fitting 142 is attached to the inlet (not shown) and the second fitting 147 is attached to the outlet (also not shown). However, in other examples not shown, the functions of the inlet and outlet may be reversed. Identification as inlet and outlet may be based on implementation-specific considerations. For example, in examples not shown, the first fitting 142 may be attached to the outlet and the second fitting 147 may be attached to the inlet.

[0034] Each of the heat transfer devices 130, the first covers 121, the second covers 122, and the cooling frame 140 are made of one or more thermally conductive materials. The first cover 121 and the second cover 122 are made of a thermally conductive material.For the purposes of this disclosure, an object, device, or assembly (which may comprise a plurality of different bodies that are thermally coupled and which may contain a plurality of different materials) is “thermally conductive” between two thermal interfaces if one of the following conditions is met: (1) a heat transfer coefficient between the thermal interfaces is 10 W m-2 K-1 or more at any temperature between 0°C and 100°C, (2) the object is a continuous piece of material that has a thermal conductivity (often denoted by k, λ, or ĸ) between the two interfaces of 1 W m-1 K-1 or more at any temperature between 0°C and 100°C, (3) the object is a heat pipe, a vapor chamber, a continuous body of copper, or a continuous body of aluminum.Examples of materials whose thermal conductivity between 0°C and 100°C is greater than 1 W·m-1·K-1 are almost all metals and their alloys (e.g. copper, aluminum, gold, etc.), some plastics (e.g. TECACOMP® TC compounds, COOLPOLY® D-Series Thermally Conductive Plastics) and many other materials.

[0035] The heat transfer devices 130, the first covers 121, the second covers 122, and the cooling frame 140 can all be made of the same material or different materials. For example, the cooling frame 140 can be injection-molded from a thermally conductive plastic, while the heat transfer device 130, the first cover 121, and the second cover 122 can be stamped from a metal sheet or a metal alloy, such as copper. Factors such as cost and weight can play a role in the selection of the material.

[0036] Typically, it is desirable that at least some of these components, such as the heat transfer device 130, the first cover 121, and the second cover 122, be made of one or more materials that are not only thermally conductive, but highly thermally conductive.An object, device, or assembly (which may include multiple different bodies that are thermally coupled and which may contain multiple different materials) is “highly thermally conductive,” as that term is used herein, between two thermal interfaces if any of the following conditions are met: (1) a heat transfer coefficient between the thermal interfaces is 1000 W m-2 K-1 or more at any temperature between 0°C and 100°C, (2) the object is a continuous piece of material that has a thermal conductivity (often denoted k, λ, or κ) between the two interfaces of 100 W m-1 K-1 or more at any temperature between 0°C and 100°C, (3) the object is a heat pipe, a vapor chamber, a continuous body of copper, or a continuous body of aluminum.Examples of materials whose thermal conductivity between 0 °C and 100 °C is 100 W m-1 K-1 or more are certain types of copper, aluminum, silver and gold.

[0037] Fig. is a schematic representation 200 of the system of Fig. used heat dissipation mechanisms, with identical parts being numbered the same. Fig. is a partially sectioned top view taken along line 2-2 in Fig. . Again, some parts of the computer system 100 - including some in Fig. parts shown - not shown for reasons of clarity, so as not to obscure what is in relation to Fig. One such part is the cooling frame 140. Instead of the cooling frame 140, a schematic representation 200 of the coolant channel defined by the cooling frame 140 is shown.

[0038] The encased PCAs 105 (only one indicated) were mounted on the first printed circuit board 101 (in Fig. shown) using the electronic sockets 102 (also shown in Fig. 1). As seen here, each heat transfer jacket 235 (only one shown) mechanically engages the PCA 110 (only one shown) through direct physical contact with one or more of the electronic components 112, 113 (only one of each shown). The physical contact also establishes a direct thermal coupling between the PCA 110 and the heat transfer jacket 235.

[0039] Also note the relationship between the jacketed PCAs 105 and the heat transfer devices 130 (only one shown) mounted on the cooling frame 140 (in Fig. shown). In the example shown, the heat transfer devices 130 are located only between the jacketed PCAs 105 and not between the jacketed PCAs 105 and the cooling frame 140. The heat transfer devices 130 physically contact the heat transfer jackets 235, as shown. Again, this physical contact establishes a mechanical engagement between the heat transfer devices 130 and the heat transfer jackets 235, but also a thermal coupling. Similarly, the direct physical contact between the heat transfer devices 130 and the cooling frame 140 (in Fig. shown) also thermally couples the heat transfer devices 130 to the cooling frame 140. However, in the examples shown here, the heat transfer devices 130 are not attached or mounted in any way to the jacketed PCAs 105.

[0040] The electronic components 112, 113 of the jacketed PCAs 105 are thus thermally connected to the cooling frame 140 (in Fig. shown). The coolant flows through the cooling channel, as indicated by the wide arrows 208. Because the cooling frame 140 is made of a thermally conductive material, it transfers the heat from the electronics 112, 113 into the coolant. Due to the direct physical contact with the walls of the coolant channel, the cooling frame 140 is thermally coupled to the coolant as the coolant circulates through the coolant channel.

[0041] Specifically, when the jacketed PCA 105 mechanically engages the cooling frame 104, heat is transferred from the electronic components 112, 113 into the coolant through the thermal coupling provided by the heat transfer jackets 235 and the cooling frame 140, as indicated by arrows 210. When the jacketed PCAs 105 are physically in contact with a heat transfer device 130, heat is transferred from the electronic components 112, 113 into the heat transfer device 130, as indicated by arrows 212, through the thermal coupling provided by the heat transfer jackets 235. The transferred heat then travels through the heat transfer device 130 to the ends, where the heat transfer device mechanically engages and is thermally coupled to the cooling frame 140. The heat is then transferred through the cooling frame into the coolant, as indicated by the arrows 214.

[0042] The coolant circulates under pressure through the coolant channel of a closed cooling circuit (not shown). The coolant is heated as it circulates through the cooling channel, circulates away from the computer system 100 to be cooled, and then circulates back to the computer system 100. The heat generated by the electronic components 112, 113 is thus managed and dissipated, allowing the computer system 100 to operate within specifications to promote the operability and efficiency of the computer system 100.

[0043] The mechanical engagement of the encapsulated PCAs 105 with the first circuit board 101 will now be described along with various aspects of the positioning of the PCAs 105. Fig. is a sectional end view of a printed circuit assembly and a first printed circuit board taken along line 3-3 in Fig. . Fig. also shows some of the mechanical clearances for components that, in this particular example, determine the thickness limitations for the heat transfer jacket. Again, it should be noted that some aspects of the computer system 100 in Fig. have been omitted for clarity. For example, no heat transfer devices 130 are shown.

[0044] The electronic sockets 102 are mounted on the first circuit board 101 in any suitable manner known in the art. The second circuit board 111 includes a plurality of edge connectors 300, such as gold finger connectors. In other examples not shown, other types of connectors may also be used. The edge connectors 300 are part of the electrical circuitry (not shown) including the electronic components 112, 113, as well as other components of the PCA 110, through which the PCA 110 performs its intended function. For this purpose, as previously discussed, the PCA 110 may include other electronic components in addition to the electronic components already discussed, such as the inductor 305 and the thyristor 310. The electrical circuitry may be implemented, for example, by surface traces and / or conductive layers of the first circuit board 101.Similarly, the electronic sockets 102 are part of the electrical circuitry of the first printed circuit board 101, which may be implemented using surface traces and / or conductive layers not shown.

[0045] The PCA 110 and hence also the encased PCA 105 are attached to the first circuit board 101 by inserting the edge connectors 300 into the electronic sockets 102. This insertion electrically connects the electrical circuitry (not shown) of the encased PCA 105 to the electrical circuitry of the first circuit board 101. Recall that, as disclosed above, the electronic sockets 102 are positioned within the inner framed space 141, which is first Fig. is shown. Thus, when assembled in this manner, the encapsulated PCAs 105 are at least partially disposed within the inner framed space 141. As explained further below, the process of inserting the encapsulated PCAs 105 into the electronic sockets 102 is accompanied by insertion into a cooling frame slot (not yet shown) defined by the cooling frame 140.

[0046] Additional shrouded PCAs 105 are shown in dashed lines to reflect assembly with the first printed circuit board 101 and to illustrate certain dimensional features of the assembly. Arrangements of closely spaced PCAs, such as DIMM banks, impose several constraints on thermal control design. The spacing between PCAs and between the PCA array and neighboring components on the motherboard may decrease with each technology generation (e.g., with increasing density). Not only are the spacings small, but they may also be awkwardly shaped. Either the size or the shape may preclude the adaptation of existing thermal control designs.

[0047] As in Fig. As shown, the sockets for the PCAs 110 have a center distance S cc on the motherboard. S ccmay be less than 9 mm or less than 8 mm, 7 mm or 6 mm. For example, S cc nominally 7.5 + / - 0.2 mm. The height of the components 112 on the PCAs 110 takes up part of the area defined by S cc allocated space. The first printed circuit board 111 may have a thickness of, for example, 0.78 mm, 1.57 mm, or 2.36 mm. Each side of the PCAs 110 may also have high components that H r Add >2.5 mm to the width of the PCA 110. Examples of tall components include some integrated circuits ("ICs") such as power management ICs ("PMICs"), as well as some non-chip electrical components such as capacitors and inductors. When tall components are mounted directly opposite each other on either side of a PCA 110, the minimum clearance C2 between the outer surfaces of the PCAs 110 can be less than 2 mm or even less than 1.5 mm when the PCAs 110 are installed in sockets 102.

[0048] If solid-state elements in thermal contact with components 112 are to be used for temperature control measures, not only the tall components are a limitation for the temperature control design. Solid-state temperature control elements, such as heat transfer devices, can also preferably be implemented with short components with a height H s <1.2 mm (e.g. some types of memory chips) and components with a medium height H m ~1.2-2.5 mm, such as various small-form-factor ICs, enter into and maintain thermal contact. The different heights of the components 112 result in different clearances C1 (maximum), C2 (minimum), and, depending on the design, one or more intermediate clearances C3 at various positions in the space between the outer surfaces of the PCAs 110.

[0049] The variety of clearances and their locations can preclude some temperature control approaches. For example, if the minimum clearance C2 is at the bottom of the PCA (closest to the receptacle interface) and the maximum clearance C1 is at the top, a tight-fitting conductive shroud that is separately mounted and pushed over the PCA(s) 110 may be easy to design and implement. If, instead, there are "overhangs" (taller components over shorter components), a "push-down" shroud design may be limited by the need to maintain thermal contact with the short components at the bottom of the PCA while avoiding stress on the tall components at the top of the PCA during installation.Alternatives such as clamshells and two-piece shrouds, where the heat transfer elements are inserted laterally from opposite sides of the PCA, may work more reliably for PCAs with overhangs because the tight-fitting sections for the short components are never pushed or pulled over the tall components.

[0050] Fig. show in more detail various aspects of an example of a jacketed PCA 400 and how a live spring 423 can be modified to accommodate different design constraints. When considering Fig. It should be noted that the above mentioned provisions Fig. discussed edge connectors 300, which define a circuit board interface 408, in Fig. The heat transfer jacket 420 includes a snap lock 404 that secures mechanical engagement of a first cover 421 and a second cover 422 around a PCA that is Fig. is covered by the heat transfer jacket 420. The snap closure 404 includes a pair of tabs 404a which are attached to the lip 406 (in Fig. shown) of the first cover 421 and engage a pair of slots 404b in the lip 407 of the second cover 422 when the first cover 421 and the second cover 422 are joined together. As a result, the lip 407 overlaps the lip 406, as shown in Fig. shown.

[0051] As in Fig. As shown, the encased PCA 400 also includes an optional plurality of pull tabs 424 attached to the lip 407 of the second cover 422. The pull tabs 424 can be used to separate the encased PCA 400 from the first circuit board 401 and the cooling frame once it has been inserted into the electronic sockets 402 in the Fig. The pull tabs 424 may be made of a flexible material so that they can be bent. For example, they may be bent when a computer system is placed in a tray (not shown) and inserted into a rack (also not shown) or other housing. In some examples, such as the example in Fig. , the pull tabs 424 can be omitted.

[0052] As in Fig. As best seen, the sheathed PCA 400 contains a plurality of live feathers 423. In some examples not shown, only one of the first cover 421 and the second cover 422 contains a plurality of live feathers 423. However, in the examples shown here, both the first cover 421 and the second cover 422 contain a plurality of live feathers 423. This is shown in the Fig. where each live spring 423 is connected to the first cover 421 or the second cover 422 in the sense that it is formed from a single piece. Both the first cover 421 and the second cover 422 are made from a single layer of material with a thermal conductivity of at least 350 W / m / K and a thickness of at most 0.25 mm. However, in other examples, materials with other thermal conductivities and other thicknesses may also be used.

[0053] Back to Fig. : A pair of jacketed PCAs 411 (only one shown) in heat transfer jackets 420 (only one shown) as in Fig. are shown in a first inset. Specifically, the shrouded PCAs 400 are installed in adjacent electronic sockets 402 of a first circuit board 401. The first circuit board 401 may be referred to as a "host board" in the sense that it "hosts" the shrouded PCAs 400. Note the use of the heat spreader 430 between the two shrouded PCAs 400. The shrouded PCAs 400 are oriented vertically with respect to gravity, while the first circuit board 401 is oriented horizontally. This is their nominal operating orientation, but other examples may use different orientations.

[0054] When the encased PCAs 400 are inserted into the electronic sockets 402, the springs 423 are forced inward relative to a centerline 418 of each encased PCA 400 by surrounding components. In the example of Fig. The compression of the live springs 423 is caused by the mechanical engagement of the heat transfer jackets 420 with the heat transfer device 430 and the spacing between the two jacketed PCAs 400. Note that such compression may similarly be caused by the mechanical engagement with an adjacent jacketed PCA 400, a heat transfer device, or the cooling frame and the associated spacing in examples without the heat transfer devices 430. Examples of this are shown in the Fig. shown and discussed below.

[0055] The live springs 423 are elastically displaced from their rest position upon insertion of the encased PCAs 400. As used herein, a live spring is capable of being "elastically deformed" if it deforms elastically when its contact surface is displaced (a) inwardly by up to 2 mm or (b) to the point where it is flush with a planar portion of the part from which the live spring originates. The live spring "deforms elastically" if the deformations resulting from the displacement are not permanent, and the live spring returns substantially to its original shape when the force that caused the displacement is removed.

[0056] The compression described above allows the jacketed PCA 400 to “squeeze” into the available space created by the cooling frame 140 (shown in Fig. ), the heat transfer devices 430 and the other jacketed PCAs 400 as defined above with respect to Fig. As soon as the jacketed PCA 400 is Fig. shown, the compressed springs 423 exert a compressive force Fs of at least about 45 N, as indicated by the arrows in Fig. and Fig. The term "approximately" used herein recognizes that an accurate indication of value may be difficult to achieve due to tolerances and errors in manufacturing, changes in material properties over time, and other similar considerations.

[0057] The compression of the springs 423 when inserting the jacketed PCA 400 into the electronic sockets 402 and the above with respect to Fig. The distances described contribute to establishing a large part of the thermal coupling mentioned above. Thus, the compression provides the physical engagement – ​​and thus the thermal coupling – between the electronic components 412, 413 and the heat transfer jacket 420. The distances described above ensure that the living spring 423 is compressed and that the heat transfer jacket 420 is physically connected to the adjacent cooling frame 140 (in Fig. (shown), the heat transfer device 430 and / or the shrouded PCA 400. Again, this physical engagement establishes a thermal coupling between all these parts of the heat transfer assembly and the computer system as a whole.

[0058] The design of the live spring 423 can be modified to allow for different designs for the deployment and arrangement of the jacketed PCAs 400. Fig. is an end view of a possible implementation of thermal devices, shown as an example with respect to a cross section such as line AA in Fig. from several very closely spaced jacketed PCAs 400 dissipating heat through the heat transfer jackets of adjacent jacketed PCAs. Fig. is an end view of a second possible implementation of heat transfer devices, shown as an example with respect to a cross section such as line AA in Fig. a higher performance jacketed PCA 400 would be used to transfer heat to external heat transfer devices. Fig. is an end view of a third possible implementation of thermal devices, shown as an example with respect to a cross section such as line AA in Fig. a jacketed high performance PCA 400 with tall components for transferring heat to a heat spreader with uneven thickness.

[0059] Fig. is a side view of the areas of thermal contact 516 between the heat transfer jacket 420 of Fig. and the underlying electronic components 412, 413 of the PCA 410. The electronic components 412, 413 are shown as hatched lines, and the areas of thermal contact are indicated by hatching. Fig. is a side view of the thermal contact areas 535 between the heat transfer jacket of Fig. and the external heat spreader (not shown) or the adjacent heat transfer jacket (also not shown in Fig. shown). Here, too, the areas of thermal contact are marked by hatching.

[0060] Back to Fig. , the first cover 421 defines a first pair of tabs 481 and the second cover 422 defines a second pair of tabs 482 (only one shown). When the first cover 421 and the second cover 422 are closed and snapped together, the two pairs of tabs form a pair of tabs 583, one of which is in the Fig. When the shrouded PCA 400 is inserted into the electronic socket 402, the tabs 583 slide into a cooling frame slot of the cooling frame, as shown below with respect to Fig. Note that in this example, one of the tabs 482 fits over one of the tabs 481. This relationship is part of the snap fit described above, in which the first cover 421 and the second cover 422 snap together to form the heat transfer jacket 420. However, in some examples, this may be omitted.

[0061] In Fig. and Fig. Selected details of the construction of the living springs 123 are now shown, which were first described in Fig. were presented. Fig. is a perspective, enlarged view of a portion of a lower edge 600 of a first cover 121 of the heat transfer jacket 135, which is first shown in Fig. shown and having live springs 123 enclosed at both ends. The live spring 135 is created by removing material from the first cover 121 on each side of the future live spring 123. A bend 626 and an opening 627 are then created. Fig. is a perspective, enlarged view of a portion of the lower edge of a cover portion of a heat transfer sleeve as shown in Fig. shown, which is formed with the live feathers 123, which are initially free at the lower end 600 and then secured by tucking into an optional hem fold 629.

[0062] As mentioned above, the living springs 123 in the example shown exert a spring force F s of at least 45 N. Fig. show two embodiments of the Fig. first shown live feathers 123. A live feather 623a in Fig. , which is formed in a second cover 622a, has a bend 626 on its underside and defines an opening 627 therein. The second cover 622a has a thickness T j of a maximum of 0.25 mm. In Fig. a live spring 623b in a second cover 622b also includes a flexure 626. However, the live spring 623b also includes a lower tab 628 extending from the flexure 626 and tucked into a hem fold 629 during manufacture.

[0063] The amount of spring force applied can be controlled by managing the implementation-specific details of each example. For example, referring to Fig. together, details such as the material selection, the thickness T j of the material, the length of the live springs 623, the total length and width of the opening 627, the length and width of the opening 627 relative to the length and width of the live spring 623, the strength of the spring force F s In some examples, different living springs 623 can have different spring forces F s For example, different springs can be dimensioned differently or have openings with different dimensions to vary the applied spring force F s Other examples may include living springs, all of which have approximately the same spring force F s exercise.

[0064] Various examples of the claimed subject matter may therefore employ living springs 123 having different spring forces F s and are not limited to a spring force F sof at least about 45 N. Some examples may therefore use live springs 123, which have a spring force F s in the range of about 55 N to about 65 N. Still other examples may employ living springs 123 that exert a spring force F s in the wider range of about 45 N to 75 N.

[0065] Furthermore, the living springs 123 disclosed herein are merely an example and illustration of the thermal coupling of the electronic components of a PCA with an external heat transfer structure. Such external heat transfer structures may include, for example, the cooling frame 140, the heat transfer device 130, and other encased PCAs 105 as disclosed herein. In other examples not shown, structures corresponding to the living springs 123 may be used to perform the stated function.

[0066] Now to go into the details of the cooling frame 140, which is first shown in Fig. was shown, is Fig. a perspective, enlarged view of a cooling frame 140 in conjunction with a heat transfer assembly 700. Fig. illustrates details of the intentionally designed turbulence-enhancing artifacts, including shape changes and bends that enhance turbulence and increase cooling efficiency. The cooling frame 140 includes a first end block 743 and a second end block 745 connected by a first side rail 744 and a second side rail 746. As previously mentioned, the cooling frame 140 can be machined from a single piece or fabricated in sections and then assembled.

[0067] As already mentioned, the direction of coolant flow through the cooling channel is not important for the functionality of the heat transfer unit 700. For simplicity, some parts of the cooling frame 140 are referred to as "inlet" or "inlet side" or similar, and other parts as "outlet" or "outlet side" or similar. However, the illustrated example has bilateral symmetry around line 702, so this inlet / outlet functionality may also be reversed. It is therefore understood that this is only a simplification and that the labeling may be reversed in other examples—even those with the same structure. On the other hand, not all examples necessarily exhibit such bilateral symmetry as the illustrated examples.

[0068] The first end block 743, the first side rail 744, the second end block 745, and the second side rail 746 together form the coolant channel. Fig. Three parts of the coolant channel are shown. An incoming end block channel 753 defined by the first end block 743 is shown in breakout 7A, and an outgoing slide rail channel 704 is shown in breakout 7B. The first end block 743 also defines an outgoing end block channel (not shown) that has a similar shape to the incoming end block channel 753. The second side rail 746 defines a similar incoming side rail channel (not shown), and the second end block 745 may define a similar second end block channel (also not shown), although they may differ in other examples. In the example shown, the outgoing side rail channel has the same structure and characteristics as the incoming side rail channel 704. However, the second end block channel, not shown, runs straight from the incoming side rail channel to the outgoing side rail channel 704.A portion of the second end block channel 755 is shown in dashed lines.

[0069] In cold plates and similar structures, turbulence occurs in the coolant flow, and attempts are typically made to design the channels and conduits through which a coolant flows to minimize and / or mitigate turbulence. However, it has been discovered that turbulence in the coolant flow can enhance heat transfer even when it impedes flow. Accordingly, the examples of the presently claimed subject matter are turbulence-enhancing artifacts that promote or enhance turbulence in the fluid flow. The illustrated examples include two different types of turbulence-enhancing artifacts: channel shape changes and bends.

[0070] In the example shown, the inlet 705 and outlet 706, as well as the first fitting 142 and the second fitting 147, have a circular cross-section, such as cross-section 708 passing through the second fitting 147 along line AA. The second end block channel, although not shown, also has a circular cross-section, such as cross-section 708. The incoming side rail channel (not shown) and the outgoing side rail channel 704 have oval cross-sections, such as cross-section 709. Accordingly, the coolant flow transitions from the circular incoming end block channel 753 into the oval incoming side rail channel, the circular second end block channel, the oval outgoing side rail channel 704, and the circular outgoing end block channel 757. Each transition from a circular cross-section to an oval cross-section and back intentionally introduces turbulence into the coolant flow.

[0071] The examples shown also utilize a number of turbulence-enhancing artifacts, including bends in the coolant channel to enhance turbulence. This discussion of bends and the associated turbulence they enhance in the examples shown focuses on the U-bend 751 and the L-bend 752, first described in Fig. was shown and in the Fig. However, the principles can also be applied to other bends at other locations in the coolant channel. When a fluid channel is bent, the resulting introduction of turbulence depends partly on the relationship between the bend radius and the channel diameter. For the same inlet flow rate, tighter bends cause more turbulence. If the circular inlet has a diameter of D, the U-bend radius is R. u for the U-bend 751, which is in Fig. shown, is less than 1.5D and the L-bend radius R lfor the L-bend 752, which is in Fig. shown, is smaller than 1.2D. These are relatively tight bends that increase turbulence.

[0072] In the end block input channel 853, the U-bend 851 is located in a first plane and the L-bend is located in a second plane orthogonal to the first plane, as in Fig. - Fig. The turbulence resulting from the successive orthogonal bends is more evenly distributed across the channel than would be the case if the U-bend 851 and the L-bend 852 were in the same plane. The distribution of convection across the channel in two orthogonal directions may be responsible for the remarkable increase in cooling performance. However, once the coolant has passed a bend, the turbulence decreases with distance from the last bend. Therefore, if the turbulence patterns of the two bends are to interact additively, the bends must be close to each other. In a modeled example, the Fig. shown distance S Bbetween the two bends 852, 853 is approximately 2.5 times the channel diameter D. It is generally believed that it is desirable for the two bends 852, 853 to be closer together than further apart. In various embodiments, the distance S B between the two arches 852, 853 approximately two to three times the diameter D.

[0073] In one example, the first side rail 744 and the second side rail 746 were made by flattening 8 mm copper tubes until the Fig. The aspect ratio h / w shown was approximately three. The circular inlet 705, the circular outlet 706, the incoming channel 753, and the outgoing channel 757 each have a diameter of D=8 mm. Thus, although the shape of the channel changes from circular to oblong, their cross-sectional area remains approximately the same: π(D2)2=Lw+π(w2)2 with L=hw, as in Fig. Maintaining the cross-sectional area throughout the shape change can prevent unwanted pressure and velocity drops in the fluid that can result from turbulence increased by bending.

[0074] Fig. - Fig. show in detail two different designs of the first end block 743, the incoming end block channel 753 and the outgoing end block channel 757 of Fig. . In Fig. and Fig. the coolant 920 enters several bends in the chamber 900 that are not strictly defined by the walls of the channel, as described above with respect to Fig. - Fig. These bends also increase the turbulence in the coolant flow, just like the turbulence in Fig. - Fig. shown design of the coolant channel.

[0075] Fig. is a perspective sectional view of an example of turbulence enhancing end block channels in the cooling frame of Fig. The first end block 743a defines a chamber 900 on both the inlet and outlet sides, in which a pair of guides 905 are arranged, which clamp the inlet 705a and in turn define an upper channel 910 and a lower channel 915. The terms "upper" and "lower" are defined relative to the gravitational field when the cooling frame 140a is in its nominal use orientation, which is Fig. - Fig. is shown.

[0076] The coolant, represented by arrows 920 (only two shown), enters the chamber 900 under pressure through the inlet 705a and flows as indicated by the arrows 920. In particular, the flow of coolant 920 is redirected through the rear of the chamber 900 into the upper channel 910 and the lower channel 915, whereupon it flows into the incoming side rail channel 925. After circulating through the first side rail 744, the second end block 745, and the second side rail 746, all in Fig. As shown, the coolant 920 returns to the first end block 743a. The coolant 920 then enters the exit chamber 900 through the upper channel 910 and the lower channel 915, from where it is directed to the outlet 706a.

[0077] Fig. is a perspective sectional view of another example of a turbulence enhancing end block channel in the cooling frame of Fig. . In this example, the inlet 705b is located relatively far down on the first end block 743b compared to the inlet 705a in Fig. . Here, too, the first end block 743b defines a chamber 900 on both the inlet and outlet sides of the end block 743b. A plurality of guides 905 are arranged in the chamber 900, forming a plurality of channels 925. The guides 905, which are larger in number than in Fig. , in this example do not enclose the inlet 705b.

[0078] The coolant 920 enters the inlet chamber 900 under pressure through the inlet 705b, is redirected, and flows as indicated by the arrows 920. The coolant 920 is redirected from the rear of the chamber 900 into the channels 915 defined by the guides 905, whereupon it flows into the incoming side rail channel 925. After circulating through the first side rail 744, the second end block 745, and the second side rail 746, all in Fig. As shown, the coolant 920 returns to the first end block 743b. The coolant 920 then enters the exit chamber 900 through the channels 930 (only one shown), whereupon it is redirected to the outlet 706b.

[0079] Back to Fig. : Both the first end block 743 and the second end block 745 each define a plurality of cooling frame slots 748, 749. The cooling frame slots 748, 749 and the electronic sockets 402 (shown in Fig. define the PCA slots like the PCA slots 120 in Fig. The sheathed PCA 400 is / are inserted into the Fig. shown electronic socket 402, which are arranged in the framed interior 741, as described above, but not in Fig. This insertion includes the insertion of the Fig. - Fig. shown tabs 583 into the cooling frame slots 748, 749 of the cooling frame 740. This establishes a mechanical engagement and thermal coupling between the jacketed PCA 400 and the cooling frame 740 at this point of insertion into the cooling frame slots 748, 749. When heat transfer devices, such as the heat transfer devices 430 in Fig. - Fig. , inserted into separate cooling frame slots between the shrouded PCAs 400 and the structure of the respective end blocks 743, 745, as described with respect to Fig. is discussed.

[0080] The turbulence-enhancing artifacts cause increased turbulence, which in turn increases the efficiency of heat transfer into the coolant, thereby reducing the area of ​​thermal contact compared to laminar flow to achieve the same heat transfer. Fig. and Fig. respectively show a packaged PCA 1005 and a heat transfer device 1030 inserted into an electronic socket 1002 attached to a first circuit board 1001 and a cooling frame base 1048. Fig. is a sectional side view of a thermal contact area A L between a shroud or heat transfer device 1030 and a cooling frame slot 1048 when the channel has an L-bend but no U-bend or shape change. Fig. is a sectional side view of a thermal contact surface A Tbetween a shell or heat transfer device 1030 and a cooling frame slot 1048 when the channel has an L-bend, a U-bend, and a shape change. Note the difference in thermal contact area between the two.

[0081] Fig. shows another example where two cooling frames and heat transfer assemblies are arranged back to back. Fig. is in particular a perspective view (with a flow diagram superimposed) of a double version of the cooling frame 740 of Fig. , capable of cooling two banks of closely spaced PCAs. The cooling frame 1140 includes two first end blocks 1143a, 1143b and a center block 1145. The center block 1145 can generally be thought of as two interconnected second end blocks 1145a, 1145b. Note the single center block channel 1107 of the coolant flow path 1150, in which the coolant, the flow of which is represented by the arrows 1107, flows from both sides 1140a, 1140b. Each of the first end blocks 1143a, 1143b receives coolant through the respective first ports 1142a, 1142b and discharges coolant through the respective second ports 1147a, 1147b.

[0082] The cooling frame 1140 is attached to a first circuit board 1101. Each cooling frame side 1140a, 1140b defines a corresponding framed interior 1141a, 1141b, as described above with respect to the cooling frame 140 of Fig. Although not shown for reasons of clarity, a variety of electronic sockets, such as those in Fig. shown electronic socket 402, attached to the first circuit board 1101 within the framed interior spaces 1141a, 1141b.

[0083] Each of the end blocks 1143a, 1143b also defines a corresponding plurality of cooling frame slots 1149a, 1149b, as does the center block 1145, as described above with respect to the cooling frame 740 in Fig. Coated PCAs such as those described in Fig. The jacketed PCA 400 shown can then be inserted into the cooling frame sockets 1149a, 1149b and electronic sockets (not shown), where they are cooled during operation as described above. Note that neither the end blocks 1143a, 1143b nor the center block 1145 have slots for inserting heat transfer devices. In the example of Fig. No heat transfer devices are used.

[0084] Fig. is a top view of a host board 1200 for a computer system with PCA socket banks equipped with the dual cooling frame of Fig. are compatible. In particular, the first printed circuit board 1201, which serves as the host board, includes, in addition to the cooling frame 1140, multiple rows of PCA socket arrays 1271 (only one shown). Note the socket assemblies 1271 disposed within the framed interiors of the cooling frame 1100. The first printed circuit board also includes a processor socket 1272, a voltage regulator socket 1273, a memory socket 1274, and an expansion socket 1275. Note that many of these features are implementation-specific, and that other examples may include other structures in addition to, or instead of, those shown.

[0085] Fig. - Fig. show various examples for a different number of jacketed PCAs and heat transfer devices. Each of the cooling frames 1340a, 1340b, 1340c defines a corresponding coolant channel 1350a, 1350b, 1350c, shown in dashed lines. The second end block channels 1370a, 1370b, 1370c are also shown. The portions of the coolant channels 1350a, 1350b, 1350c defined by the respective first end blocks 1343a, 1343b, 1343c may include chambers, guides, and channels as described with respect to Fig. discussed, although these are not shown. Note also the protrusions 1355 in the side rails of the cooling frames 1340a, 1340b, 1340c, which also increase the turbulence in the coolant flow.

[0086] Fig. is a top view of a cooling frame 1340a and a heat transfer jacket 1320 for a single high-performance PCA 1310a. The first end block 1343a defines a first cooling frame slot 1348a, and the second end block 1345a defines a second cooling frame slot 1349a into which the PCA 1310a and heat transfer jacket 1320 are inserted. This example is particularly useful when a PCA 1310a consumes a lot of power and therefore generates a relatively large amount of power, justifying a dedicated heat transfer unit. Note the absence of a heat transfer device given the direct thermal coupling of the jacketed PCA 1310a.

[0087] Fig. is a top assembly view of a cooling frame 1340b for an array of moderately powerful, closely spaced, jacketed PCAs 1305b without heat transfer devices. The first end block 1343b defines a plurality of first cooling frame slots 1348b (only one shown), and the second end block 1345b defines a plurality of second cooling frame slots 1349b (only one shown) into which the PCAs 1310b and heat transfer jackets 1320 are inserted. Again, note that no heat transfer devices are present.

[0088] Fig. is a top view of a cooling frame 1340c and shrouded PCAs 1305c for a series of lower-power, but very closely spaced, PCAs 1310c. The first end block 1343c defines a plurality of first cooling frame slots 1348c (only one shown), and the second end block 1345c defines a plurality of second cooling frame slots 1349c (only one shown). In this example, the PCAs 1310c and heat transfer jackets 1320 are not inserted into the cooling frame slots 1348c, 1349c. The PCAs 1310c are only inserted into the sockets (not shown). Instead, the heat transfer devices 1330 are inserted into the cooling frame slots 1348c, 1349c, as shown.

[0089] Note also the presence of the heat transfer devices 1330 in the example of Fig. Inserting the heat transfer devices 1330 into the slots of the cooling frame 1353, 1354 (only one at a time) establishes physical engagement and thermal coupling with the shrouded PCAs 1305c. The insertion also establishes physical engagement and thermal coupling between the heat transfer devices 1330 and the cooling frame 1340c. Consequently, the insertion thermally couples the PCAs 1305c to the first end block 1343c and the second end block 1345c.

[0090] Those skilled in the art familiar with this disclosure will recognize yet further variations in the number of shrouded PCAs, the number of heat transfer devices, and combinations thereof with which the cooling frames described herein may be employed. These numbers and configurations are implementation-specific and depend on the amount of heat generated by the shrouded PCAs and the design constraints for mitigating or dissipating that heat. Accordingly, various examples of the subject matter claimed below are not limited to the number of shrouded PCAs and heat transfer devices shown in the illustrated examples, nor to the configurations shown.

[0091] In various examples, the design of the heat transfer device can be varied when heat transfer devices are used. Heat spreaders arranged between jacketed PCAs can serve both thermal and mechanical functions. Thermally, they spread the heat dissipated by adjacent PCA components through the heat transfer jackets. Mechanically, they compress the heat transfer jacket springs against the PCA components.

[0092] The socket pitch on the motherboard in conjunction with the PCA substrate thickness and the positions and heights of the PCA components sets an upper limit for the thickness of the heat spreader (see, for example, the discussion of Fig. This upper limit can vary depending on the position across the length and width of the heat spreader. At the same time, the range of usable heat spreader materials is limited by the amount of heat that must be dissipated within the limited thickness. Finally, the heat spreader must be sufficiently rigid to maintain the compression of the living feathers over a service life of years without deforming; this may imply a lower limit for the thickness.

[0093] Fig. is a side view of the heat transfer device 1430 of Fig. The heat transfer device 1430, in this example, is a heat spreader. The heat transfer device 1430 includes a cutout or recess 1431 for conforming to the contours of certain electronic components (not shown) of the encapsulated PCA (also not shown) with which the heat transfer device 1430 is to be physically engaged and thermally coupled. The heat transfer device 1430 also includes an end taper 1432 and an end tab 1433 with which the heat transfer device 1430 engages the cooling frame slots (not shown) of the cooling frame (also not shown).

[0094] Fig. is a sectional view through section DD of Fig. for an example of a heat transfer device 1430b that is a solid heat spreader. In particular, the heat transfer device 1430 is a solid heat spreader, and more specifically, a solid copper example of the heat spreader made of Fig. . It should be noted that only a portion of the heat transfer device 1430b is shown. The heat transfer device 1430b has a solid body with a thickness of T T in the end tab 1433 and the end taper 1432 (not shown) and a thickness of T B in between.

[0095] The case thickness T Bthat dissipates sufficient heat and provides sufficient stiffness for reliable uniform spring loading can be 2-5 mm, e.g., 3.5 mm. In some examples, this may be too wide to fit between tall components on adjacent shrouded PCAs. If only a limited area on the PCA (e.g., less than 50% or less than 25%) is occupied by tall components, the tightest spaces can be filled by recesses (such as a cutout or recess 1431 in Fig. or increments (such as end plate 1433) so that overall heat dissipation and stiffness are minimally affected.

[0096] The thickness of the tab T TFor example, it may be as small as 0.1-0.2 mm, but it may only represent a small part of the total surface area of ​​the heat spreader. Additionally or alternatively, the cutout or tab may be located near the cooling frame slot, where its rigidity is enhanced by the slot walls and any heat buildup is dissipated by the fluid flowing through the cooling block. However, if the desired cutouts or tabs represent too large a portion of the heat spreader surface area or are located in a location unfavorable for heat buildup, a material with higher conductivity (or a more complex structure such as a vapor chamber) may achieve the desired heat dissipation and rigidity with a smaller body thickness T B offer.

[0097] Fig. is a sectional view through section DD of a hollow example of the heat spreader of Fig. In this example, the body of the heat transfer device 1430c defines an air pocket or space 1436 between the end tab 1433 and the end cone (not shown). The air pocket 1435 is open to the ambient atmosphere through the bottom of the heat transfer device 1430c.

[0098] Because the hollow interior 1436 is made of air, gas or a vacuum and not of a highly heat-conducting material, it weighs less than the solid heat spreader of Fig. The hollow heat spreader can also cost less than its solid counterpart if the manufacturing costs of the hollow example do not fully offset the material savings. The thickness T W,H of the walls surrounding the hollow interior 1436 is preferably sufficient to ensure the required rigidity and heat dissipation.

[0099] Fig. is a sectional view (through section DD of Fig. An example of a heat transfer device 1430d that is a heat spreader for the evaporator chamber. In this example, the evaporator chamber functions as a flattened heat pipe. Specifically, between the end taper (not shown) and the end tab 1433, the body of the heat transfer device 1430d defines a vapor chamber with a vapor core 1437 and a wick layer 1438. The vapor chamber is enclosed and insulated from the ambient atmosphere.

[0100] The vapor core 1437, which can optionally extend into thinner areas such as the flap, is filled with a thermal phase change material and lined with a very thin (<0.2 mm) wicking layer 1438. The phase change material is applied to the “hot interface” (thermal contact area between the jacket and the heat spreader, area 535 in Fig. to a gas. The gas expands and flows through the core 1437 to the “cold interface” (thermal contact area between the cooling frame and the heat spreader, area A L in Fig. or area A T in Fig. There it condenses again into a liquid and flows along the wick layer 1438 back to the hot interface.

[0101] The effective thermal conductivity of a vapor chamber depends partly on its dimensions, but for sizes similar to the heat spreaders described here, it can reach or exceed 10 kW / m / K. In contrast, the thermal conductivity of the copper walls is 0.3–0.4 kW / m / K; therefore, the phase-change material in the 1437 core performs most of the heat dissipation. The copper walls only need to provide sufficient stiffness to support the loads of the live springs in the adjacent heat transfer jackets. The thickness T W,Vof the copper walls surrounding the vapor chamber core 1437 can be 0.4-0.6 mm, e.g. 0.5 mm.

[0102] The three in Fig. The heat spreaders shown were compared in a thermal model for a temperature control system for densely packed PCAs. 14B-14D were compared in a thermal model of a temperature control system for an array of densely packed PCAs. The system included a cooling frame and jacketed PCAs, as well as the heat spreaders. The wall material of the modeled heat spreaders was copper, and the body thickness was T B was 3.5 mm and the thickness of the tabs T T 0.15 mm.

[0103] Those skilled in the art familiar with this disclosure will understand that other variations of the heat transfer device of the claimed subject matter may be implemented in addition to those presented herein. Furthermore, the choice between variations is implementation-specific and depends on the amount of heat generated by the jacketed PCAs and the design constraints for mitigating or dissipating that heat. Other constraints such as performance, cost, manufacturability, etc., may also influence the choice.

[0104] Fig. are data diagrams of thermal model results for the cooling system of Fig. with the three alternative heat transfer devices of the Fig.in a specific example. As mentioned previously, the examples shown are memory cards populated with DIMMs. Each of the data graphs shows DIMM power consumption compared to the DIMM operating thermal limit. Points 1563A, 1563B, and 1563C represent design operating points. Regions 1561A, 1561B, and 1561C are the operating regions where operation approaches the limit to remain within the specification. Regions 1562A, 1562B, and 1562C are the regions where operation exceeds the limit to remain within the specification.

[0105] This concludes the detailed description. The above examples are for illustrative purposes only, as the technique disclosed herein may be modified and practiced in different but equivalent ways, as will be apparent to one skilled in the art having the benefit of the teachings contained herein. Furthermore, no limitations are intended on the details of construction or embodiment shown herein that are not described in the following claims. It is therefore obvious that the above-disclosed examples may be altered or modified, and all such variations are contemplated within the scope and spirit of the appended claims. Accordingly, the protection sought herein is as set forth in the following claims.

Claims

[1] A heat transfer assembly (700) comprising: a heat transfer jacket (135; 235; 420; 1320); and a cooling frame (140; 740; 1140; 1340a; 1340b; 1340c) with which the heat transfer jacket (135; 235; 420; 1320) is mechanically engaged and with which the heat transfer jacket (135; 235; 420; 1320) is thermally coupled, wherein the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c) defines: an inner framed space (141) in which at least a portion of the heat transfer jacket (135; 235; 420; 1320) is arranged; and a coolant channel (1350a; 1350b; 1350c) comprising at least one turbulence-enhancing artifact for selectively increasing turbulence in a liquid flow through the coolant channel (1350a; 1350b; 1350c), wherein the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c) comprises a first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c), a second end block (745; 1145a; 1145b; 1345a; 1345b; 1345c) opposite the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c), an incoming side rail extending between the first and second end blocks, and an outgoing side rail extending between the first and second end blocks, wherein the inner framed space (141) is defined between the first and second end blocks and between the incoming and outgoing side rails, and wherein the coolant channel (1350a; 1350b; 1350c) extends from an inlet (705; 705a; 705b) into a first portion of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c), from the first portion of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c) into the incoming side rail, from the incoming side rail into the second end block (745; 1145a; 1145b; 1345a; 1345b; 1345c) and from the second end block (745; 1145a; 1145b; 1345a; 1345b; 1345c) into the outgoing side rail, from the outgoing side rail into a second portion of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c) and from the second portion of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c) into an outlet (706; 706a; 706b). [2] The heat transfer assembly of claim 1, wherein the inlet (705; 705a; 705b) has a circular cross-section; wherein the outlet (706; 706a; 706b) has a circular cross-section; and wherein the coolant channel (1350a; 1350b; 1350c) comprises a portion between the inlet and the outlet having an oval cross-section. [3] The heat transfer assembly of claim 2, wherein: the section of the coolant channel (1350a; 1350b; 1350c) between the inlet (705; 705a; 705b) and the outlet (706; 706a; 706b) contains the at least one turbulence-enhancing artifact of the coolant channel (1350a; 1350b; 1350c); and the at least one turbulence-enhancing artifact further comprises curvatures and shape changes to further enhance the turbulence of the liquid flow through the coolant channel (1350a; 1350b; 1350c). [4] The heat transfer assembly of claim 2, wherein the portion of the coolant channel (1350a; 1350b; 1350c) between the inlet (705; 705a; 705b) and the outlet (706; 706a; 706b) comprises: a first end block channel (753) in the first portion of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c) fluidly connected to the inlet (705; 705a; 705b); a second end block channel (755; 1370a; 1370b; 1370c) in the second end block (745; 1145a; 1145b; 1345a; 1345b; 1345c); a third end block channel in the second portion of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c) fluidly connected to the outlet (706; 706a; 706b); an incoming side rail channel (925) in the incoming side rail, the incoming side rail being in fluid communication with the first end block channel (753) and the second end block channel (755; 1370a; 1370b; 1370c); and an outgoing side rail channel in the outgoing side rail in fluid communication with the second end block channel (755; 1370a; 1370b; 1370c) and the third end block channel. [5] The heat transfer assembly of claim 1, wherein the heat transfer jacket (135; 235; 420; 1320) comprises: a first cover (121; 421) defining a first pair of tabs (481) through which the heat transfer jacket (135; 235; 420; 1320) is mechanically engaged and thermally coupled to the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c); a second cover (122; 422) opposite and mechanically engaged with the first cover (121; 421) and defining a second pair of tabs (482) through which the heat transfer jacket (135; 235; 420; 1320) is mechanically engaged and thermally coupled to the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c); and a first live spring (423) integral with the first cover. [6] The heat transfer assembly of claim 5, wherein the heat transfer jacket (135; 235; 420; 1320) further comprises a second live spring (423) integral with the second cover (122; 422). [7] The heat transfer assembly of claim 1, further comprising a heat transfer device (130; 430; 1030; 1330; 1430; 1430b; 1430c; 1430d) thermally coupled to the heat transfer jacket (135; 235; 420; 1320) and the cooling frame (140; 740; 1140; 1340c). [8] The heat transfer assembly of claim 7, wherein the heat transfer device (130; 430; 1030; 1330; 1430; 1430b; 1430c; 1430d) is a heat spreader. [9] A computer subassembly comprising: a printed circuit assembly (110) comprising: a printed circuit board (111); and a plurality of electronic components (112, 113; 412; 413) mounted on the circuit board (111); a heat transfer assembly comprising: a heat transfer jacket (135; 235; 420; 1320) surrounding and mechanically engaging the printed circuit assembly and thermally coupled to the printed circuit assembly; and a cooling frame (140; 740; 1140; 1340a; 1340b; 1340c) with which the heat transfer jacket (135; 235; 420; 1320) is mechanically engaged and with which the heat transfer jacket (135; 235; 420; 1320) and the printed circuit assembly (110) are thermally coupled, the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c) defining: an inner framed space (141) in which at least a portion of the heat transfer jacket (135; 235; 420; 1320) is arranged; and a coolant channel (1350a; 1350b; 1350c) comprising at least one turbulence-enhancing artifact for selectively introducing turbulence into a liquid flow through the coolant channel (1350a; 1350b; 1350c), wherein the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c) comprises a first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c), a second end block (745; 1145a; 1145b; 1345a; 1345b; 1345c) opposite the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c), an incoming side rail extending between the first and second end blocks, and an outgoing side rail extending between the first and second end blocks, wherein the inner framed space (141) is defined between the first and second end blocks and between the incoming and outgoing side rails, and the coolant channel (1350a; 1350b; 1350c) extends from an inlet (705; 705a; 705b) into a first section of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c), from the first section of the first end block into the incoming side rail, from the incoming side rail into the second end block (745; 1145a; 1145b; 1345a; 1345b; 1345c), from the second end block (745; 1145a; 1145b; 1345a; 1345b; 1345c) into the outgoing side rail, from the outgoing side rail into a second section of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c) and from the second portion of the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c) into an outlet (706; 706a; 706b). [10] The computer subassembly of claim 9, wherein the printed circuit board (110) is a memory board. [11] The computer subassembly of claim 9, wherein the electronic components (112, 113; 412) comprise a plurality of dual in-line memory modules ("DIMMs"). [12] The computer subassembly of claim 9, wherein the coolant channel (1350a; 1350b; 1350c) comprises: an inlet (705; 705a; 705b) having a circular cross-section; an outlet (706; 706a; 706b) having a circular cross-section; and a section between the inlet (705; 705a; 705b) and the outlet (706; 706a; 706b) having an oval cross-section. [13] The computer subassembly of claim 12, wherein: the section comprises at least one turbulence-enhancing artifact of the coolant channel (1350a; 1350b; 1350c); and the at least one turbulence-enhancing artifact comprises curvatures and shape changes to enhance the turbulence of a liquid flowing through the coolant channel (1350a; 1350b; 1350c). [14] The computer subassembly of claim 9, wherein the heat transfer jacket (135; 235; 420; 1320) comprises: a first cover (121; 421), wherein the first cover (121; 421): a first pair of tabs (481) is defined by which the heat transfer jacket (135; 235; 420; 1320) is mechanically engaged and thermally coupled to the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c); the printed circuit assembly (110) is thermally coupled to the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c); and covers at least a first portion of a first side of the printed circuit assembly (110); a second cover (122; 422) opposite and mechanically engaged with the first cover (121; 421), and: defining a second pair of tabs (482) through which the heat transfer jacket (135; 235; 420; 1320) is mechanically engaged and thermally coupled to the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c); which thermally couples the printed circuit assembly (110) to the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c); and which covers at least a second part of a second side of the printed circuit assembly (110); and a first live spring (423) integral with the first cover (121; 421), the first live spring (423) being urged against a first component of the plurality of electronic components (112, 113; 412; 413) mounted on the printed circuit assembly (110) is pressed to mechanically engage the first cover (121; 421) with the printed circuit assembly (110) to: mechanically engaging the heat transfer jacket (135; 235; 420; 1320) with the printed circuit assembly (110); and to thermally couple the printed circuit assembly (110) to the heat transfer jacket (135; 235; 420; 1320) and the cooling frame (140; 740; 1140; 1340a; 1340b; 1340c). [15] The computer subassembly of claim 9, further comprising a heat transfer device (130; 430; 1030; 1330; 1430; 1430b; 1430c; 1430d) thermally coupled to the heat transfer jacket (135; 235; 420; 1320) and the cooling frame (140; 740; 1140; 1340c). [16] The computer subassembly of claim 15, wherein the heat transfer device (130; 430; 1030; 1330; 1430; 1430b; 1430c; 1430d) is thermally coupled to the heat transfer jacket (135; 235; 420; 1320) by mechanical engagement. [17] The computer subassembly of claim 15, wherein the heat transfer device (130; 430; 1030; 1330; 1430; 1430b; 1430c; 1430d) is a heat spreader. [18] A computer system (100) comprising: a first circuit board (101; 401; 1201) comprising a socket (102; 402; 1002); and The computer subassembly of any one of claims 9 to 17, wherein the cooling frame is attached to the first circuit board (101; 401; 1201) such that the inner framed space (141) encompasses the socket (102; 402; 1002), and the printed circuit assembly is mechanically and electrically engaged with the socket (102; 402; 1002) of the first circuit board (101; 401; 1201) within the inner framed space (141). [19] The computer system (100) of claim 18, wherein the first circuit board (101; 401; 1201) has length, width and thickness dimensions and comprises: a first surface parallel to the length and width dimensions, a second surface parallel to and opposite the first surface, an edge connecting the first and second faces, and an edge connector (300) on the edge configured to communicatively connect the printed circuit assembly (110) to another electronic device; wherein the heat transfer jacket (135; 235; 420; 1320) comprises a first cover (121; 421) extending along and mechanically and thermally coupled to a first side of the printed circuit assembly (110) comprising the first surface, and a second cover (122; 422) extending along and mechanically and thermally coupled to a second side of the printed circuit assembly (110) comprising the second surface; wherein the first cover (121; 421), the second cover (122; 422), or both of the first and second covers comprise live springs (423) integral with the first cover (121; 421) and / or the second cover (122; 422), each of the live springs (423) being urged by a spring force toward the printed circuit assembly (110) to contact the printed circuit assembly and thermally couple the printed circuit assembly (110) to the heat transfer jacket (135; 235; 420; 1320). [20] The computer system (100) of claim 19, wherein the first cover (121; 421) and the second cover (122; 422) define a pair of tabs positioned at opposite ends of the heat transfer jacket (135; 235; 420; 1320) relative to the length dimension of the first circuit board (101; 401; 1201), wherein one of the tabs is mechanically engaged and thermally coupled to the first end block (743; 743a; 743b; 1143a; 1143b; 1343a; 1343b; 1343c) and the other of the tabs is mechanically engaged and thermally coupled to the second end block (745; 1145a; 1145b; 1345a; 1345b; 1345c).

Images