Fan sink heat dissipation device
A heat dissipation device, having a base plate for making contact with a heat producing integrated circuit; several fins disposed on and partially covering the base plate, the fins forming flow channels and the fins and the flow channels having proximal ends and distal ends. The device also includes a fan mounted on the base plate for delivering air flow to the fins, the fan being configured to deliver air to the proximal ends of the fins. The device also includes a shroud disposed over the fins and the fan. The shroud has an aperture that has a shape generally matching the overall shape of the fan, where the aperture acts as an air inlet for the fan. The device also includes members for fastening the heat dissipation device against the heat producing integrated circuit. The fastening members hold in alignment the shroud and the base plate against a printed circuit board having the heat producing integrated circuit.
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This application claims priority to U.S. Patent Application No. 60/506,055, filed Sep. 24, 2003, the disclosure of which is hereby incorporated by reference herein in its entirety for all purposes.
BACKGROUND OF THE INVENTIONThe present invention relates to heat sinks, and in particular, to heat sinks including fans that are coupled to graphic cards so that the heat generated by the card can be effectively managed.
Semiconductors, including microprocessors and other integrated circuits (ICs), generate heat during use. Current microprocessors, for example, can emit 50 watts of power or more. The temperature of the microprocessor or the IC has a direct impact upon its performance. Unless microprocessors and other ICs are thermally managed during use, they will not operate reliably. Failures include phenomena such as junction fatigue, electromigration diffusion, thermal runway, and electrical parameter shifts. For most uses of a semiconductor device, a proper mechanism for heat dissipation is needed.
Heat may be transferred from a device by convection, radiation, or conduction. Convection is the transfer of heat by moving air. Radiation is the transfer of heat from one surface to another via electromagnetic waves. Conduction is the transfer of heat from the more energetic particles of a substance to the less energetic particles of a substance, and it does not involve convention. Conduction is typically considered as transfer of heat within materials (e.g. solids, liquids, or gases), from a higher temperature region to a lower temperature one. Each of these principles may have a part in the operation of heat sinks.
Heat sinks are devices that attach directly or indirectly to a semiconductor or other hot surface to enhance heat dissipation from the surface. Heat flows from the hot surface to cooler air through the heat sink. A heat sink is generally designed with a first surface, for engaging with the semiconductor, and a second surface, for contact with the cooler air. The second surface, often formed of a plurality of projections or fins, is designed for maximum surface area, and thus maximum contact with the air, to allow heat to dissipate more quickly.
To further facilitate air flow from the hot surface, many heat sinks include small fans mounted thereon. Heat pipes may also form part of the heat sink, allowing heat transfer to the liquid or gas within the pipes. Heat sinks may be painted or anodized to enhance the effect of radiation heat transfer.
Recently, advances in computer graphics simulation have created thermal design challenges for graphics cards. These challenges are partly driven by the increased power dissipation of the graphic processing unit (“GPU”) and associated memory and other devices of the graphic cards. In addition to the increased heat dissipation, such graphics cards need to operate in the ever-decreasing available real estate of typical graphics workstations. For example, it is desirable to have a graphics cards not take up more space than one expansion slot (e.g., a Personal Computer Interface [PCI] slot).
Thus, there is a continuing need to support heat-producing integrated circuits, such as those of a graphics card, with an improved heat dissipating device.
BRIEF SUMMARY OF THE INVENTIONThe present invention provides a heat dissipation device, having a base plate for making contact with a heat producing integrated circuit; several fins disposed on and partially covering the base plate, the fins forming flow channels and the fins and the flow channels having proximal ends and distal ends. The device also includes a fan mounted on the base plate for delivering air flow to the fins, the fan being configured to deliver air to the proximal ends of the fins. The device also includes a shroud disposed over the fins and the fan. The shroud has an aperture that has a shape generally matching the overall shape of the fan, where the aperture acts as an air inlet for the fan. The device also includes members for fastening the heat dissipation device against the heat producing integrated circuit. The fastening members hold in alignment the shroud and the base plate against a printed circuit board having the heat producing integrated circuit.
In one aspect, the flow channels extend radially outward in a fanned-out manner from the proximal ends to the distal ends. The proximal ends are arranged along an arc which is complimentarily shaped with a portion of the aperture of the shroud.
In another aspect, a first flow channel of the fins is generally parallel with a longitudinal axis of the printed circuit board and a last flow channel of the fins is nonparallel and angled with respect to the first flow channel, and the remaining flow channels between the first and the last flow channel are incrementally angled away from the first channel and incrementally aligned with the last flow channel, so as to form a radially extending fan-shaped series of flow channels that are formed by the fins.
For a further understanding of the nature and advantages of the invention, reference should be made to the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 3A-C show exemplary views of a first embodiment of the heat dissipation device in accordance with the present invention.
FIGS. 4A-B show exemplary views of the backside of the heat dissipation device of
FIGS. 5A-B show exemplary views of an alternate embodiment of the backside of the heat dissipation device of
FIGS. 9A-B show exemplary views of alternate embodiments of the heat dissipation device having an intake air duct in accordance with the present invention.
FIGS. 14A-D show exemplary views of a second embodiment of the heat dissipation device in accordance with the present invention.
FIGS. 15A-H show exemplary views of a third embodiment of the heat dissipation device in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION FIGS. 3A-C show exemplary views of a first embodiment of the heat dissipation device in accordance with the present invention.
The shroud 306 covers the finned section and ensures that the air flow provided by the fan 308 does not bypass the finned section 304 thus ensuring that the airflow gets delivered to the flow channels of the finned section. The shroud surrounds the fan around the fan's perimeter and encloses the region around the finned section and the fan. The shroud has openings in the regions of the fan air inlet and the inlet to the finned section which is adjacent to the fan. In this manner, the shroud ensures that non preheated air is drawn into the fan at the fan's inlet and then delivered to the inlet of the flow channels of the finned section, which are adjacent to and aligned with the air exit of the fan. The cooling air provided by the fan is not wasted or lost to any region and is directed to the flow channels that are formed by the finned section or region. The shroud also has openings along the exits of the flow channels.
Also shown in
The shroud 306 includes members that are used to hold the larger 304 and smaller finned portions (e.g., 324, 334, shown in
FIGS. 4A-B show exemplary views of the backside of the heat dissipation device of
FIGS. 5A-B show exemplary views of an alternate embodiment of the backside of the heat dissipation device of
FIGS. 9A-B show exemplary views of alternate embodiments of the heat dissipation device having an intake air duct in accordance with the present invention.
FIGS. 14A-D show exemplary views of a second embodiment of the heat dissipation device 600 in accordance with the present invention. This second embodiment of the heat dissipation device 600 uses arrays of folded fins 602 to form the finned section that is disposed above the base plate. As shown in FIGS. 14A-B, the heat dissipation device is configured to cool a card 604 having one GPU and several (e.g., 8-16) memory or SRAM modules 606, using arrays of folded fins. The folded fin is designed to form a sufficient convective surface for the heat dissipation device. Furthermore, the embodiment shown in FIGS. 14A-B relies on an improved air delivery system supplied by a blower 608. SRAMs on the front side are cooled by the cooling air provided through the finned section. Heat from SRAMs on the back side (shown in
The folded fins that are arranged in the arrayed manner next to one another, can be arranged so that they butt up against one another in the direction of the flow or be placed as shown in
FIGS. 15A-H show exemplary views of a third embodiment of the heat dissipation device in accordance with the present invention. This third embodiment of the heat dissipation device 702 uses arrays of stacked fins 708 to form the finned section that is disposed above the base plate. Shown in
Each of the several C-shaped stacked fins is thin-walled. As used herein, thin-walled refers to a thickness on the order of 0.2-0.3 mm. The thin-walled fins ensure that an adequate flow channel is formed that does not produce a large back pressure that would impeded an adequate air flow rate. An adequate flow channel is formed in the finned section by providing a fin-to-fin spacing that is on the order of 2-3 times the fin's thickness. So, for example, with fins having a wall thickness of 0.2 mm, a 0.6 mm fin spacing is used. This combination of fin thickness and spacing is not achievable with conventional heat sinks that are manufactured using either extrusion or die cast techniques. Furthermore, the use of the stacked fin arrangement also enables the formation of fins as tall as desired (as compared to their thickness); to have aspect ratios (e.g., height to thickness ratio) much higher than those available in conventional heat sinks that are manufactured using either extrusion or die cast techniques. In addition, the use of the thin-walled stacked fin arrangement also enables the production of an effective heat dissipation device having a low weight.
Also shown in
Shroud 712 is also designed to enhance the overall performance of the heat dissipation device. As is shown in
In addition, as shown in
A comparison of
The heat dissipation device in accordance with the embodiments of the present invention in general, and the device 702 (i.e., the third embodiment) provide the following performance results. The single slot or shorter fin height device (e.g.,
As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. For example, the base plate and the finned section may be made of the same or different high conductivity materials and may be joined together using any suitable techniques, including soldering. These other embodiments are intended to be included within the scope of the present invention, which is set forth in the following claims.
Claims
1. A heat dissipation device, comprising:
- a base plate for making contact with a heat producing integrated circuit;
- a plurality of fins disposed on and partially covering said base plate, said fins forming flow channels and said fins and said flow channels having proximal ends and distal ends;
- a fan mounted on said base plate for delivering air flow to said plurality of fins, said fan configured to deliver air to said proximal ends of said fins;
- a shroud disposed over said fins and said fan, said shroud having an aperture having a shape generally matching the overall shape of said fan, said aperture acting as an air inlet for said fan; and
- means for fastening said heat dissipation device against the heat producing integrated circuit, wherein said means for fastening hold in alignment said shroud and said base plate against a printed circuit board having the heat producing integrated circuit.
2. The device of claim 1 wherein said flow channels extend radially outward in a fanned-out manner from said proximal ends to said distal ends, said proximal ends being arranged along an arc which is complimentarily shaped with a portion of said aperture of said shroud.
3. The device of claim 2 wherein a first flow channel of said plurality of fins is generally parallel with a longitudinal axis of said printed circuit board and a last flow channel of said plurality is nonparallel and angled with respect to said first flow channel, and the remaining flow channels between said first and said last flow channel are incrementally angled away from said first channel and incrementally aligned with said last flow channel, so to form a radially extending fan-shaped plurality of flow channels formed by said plurality of fins.
4. The device of claim 2 wherein said plurality of fins comprise a corrugated fin section having a generally corrugated shape, such that said corrugated shaped fins when disposed on said base plate form said flow channels for delivering air flow provided by the fan.
6. The device of claim 5 wherein said inverted U-shaped folded fins have an aperture formed in their top portions.
7. The device of claim 2 wherein said plurality of fins comprise a plurality of individual C-shaped fins, said plurality of C-shaped fins arranged in a stacked manner to form a stacked fin array to form said flow channels.
8. The device of claim 2 wherein said plurality of fins are arranged such that the fins are spaced at a distance of 2 to 3 times that of the fin's thickness.
9. The device of claim 1 further comprising a back plate for making contact with the back side of the printed circuit board, wherein said back plate, and said base plate are held in alignment against opposite sides of a board having a heat producing integrated circuit using said shroud.
10. The device of claim 1 wherein the top internal surface of said shroud is located a distance above the top of the fins so as to create a flow channel for directing airflow provided by said fan over said top of said fins.
11. The device of claim 1 wherein said shroud comprises openings along its periphery, wherein said openings are aligned with and project outward over the distal ends of said fins, so as to direct the air flow existing the flow channels to exit from said device along said openings.
12. The device of claim 11 further comprising a plurality of stiffeners, said stiffeners extending vertically downward from the top internal surface of said shroud and inward from and along said openings, wherein said stiffeners are aligned with the flow channels formed by said fins.
13. The device of claim 1 further comprising an intake shroud, having a proximal end and a distal end, said distal end of said intake air shroud configured to be coupled with said aperture of said shroud, said proximal end of said intake air shroud configured to receive air from the outside of a chassis of a workstation holding the printed circuit board, said intake air shroud configured to provide unheated air form the outside of a chassis of a workstation holding the board into the fins via the fan.
14. The device of claim 1 further comprising a heat pipe in thermal contact with said base plate.
15. The device of claim 1 wherein said base plate and said fins are made of the same high thermal conductivity material.
16. The device of claim 1 wherein said base plate and said fins are made of different high thermal conductivity materials.
17. The device of claim 1 having a temperature rise of no more than approximately 0.7 degrees C. per watt.
18. The device of claim 1 having a temperature rise of no more than approximately 0.6 degrees C. per watt.
19. The device of claim 1 having an overall width that is less than the width of a single personal computer interface expansion slot.
20. A heat dissipation device, comprising:
- a base plate for making contact with a heat producing integrated circuit;
- a plurality of fins disposed on and partially covering said base plate, said fins forming flow channels and said fins and said flow channels having proximal ends and distal ends, wherein said plurality of fins comprise a plurality of individual C-shaped fins, said plurality of C-shaped fins arranged in a stacked manner to form a stacked fin array to form said flow channels;
- a fan mounted on said base plate for delivering air flow to said plurality of fins, said fan configured to deliver air to said proximal ends of said fins;
- a shroud disposed over said fins and said fan, said shroud having an aperture having a shape generally matching the overall shape of said fan, said aperture acting as an air inlet for said fan; and
- means for fastening said heat dissipation device against the heat producing integrated circuit, wherein said means for fastening hold in alignment said shroud and said base plate against a printed circuit board having the heat producing integrated circuit,
- wherein said flow channels extend radially outward in a fanned-out manner from said proximal ends to said distal ends, said proximal ends being arranged along an arc which is complimentarily shaped with a portion of said aperture of said shroud, and
- wherein a first flow channel of said plurality of fins is generally parallel with a longitudinal axis of the printed circuit board and a last flow channel of said plurality is nonparallel and angled with respect to said first flow channel, and the remaining flow channels between said first and said last flow channel are incrementally angled away from said first channel and incrementally aligned with said last flow channel, so to form a radially extending fan-shaped plurality of flow channels formed by said plurality of fins.
Type: Application
Filed: Apr 5, 2004
Publication Date: Mar 24, 2005
Applicant: Heatscape, Inc. (San Jose, CA)
Inventor: Ali Mira (Morgan Hill, CA)
Application Number: 10/818,751