The present invention relates generally to apparatus and methods for the spreading and dissipation of thermal energy from heat-producing components. More particularly, it relates to a removable heat transfer apparatus and methods particularly useful in the electrical arts.
Many electronic components produce significant and potentially damaging levels of heat during operation. In certain cases, it is necessary to augment the dissipation of the heat from the components by the use of cooling apparatus. Heat management is especially critical in computer systems, not only to protect the heat-producing components from the effects of high temperatures, but also to protect surrounding components and structures. Considering that computer components are commonly housed in compact enclosures, heat management becomes increasingly important to maintain safe operating temperatures.
One computer component that generates significant levels of heat is the memory chip. Memory chips, such as random assess memory (RAM) chips, are electronic components that store data and instructions for processing by a central processing unit (CPU). Memory chips come in many different packaging configurations, but most share the general shape of a low profile rectangular box or plate.
In early computer design, memory chips were mounted directly to the computer motherboard, otherwise known as the mainboard. Today, memory chips are typically assembled into what is referred to as a memory module. There are three major components that make up a memory module: the memory chips, a printed circuit board (PCB), and other xe2x80x9con-boardxe2x80x9d elements such as resistors and capacitors. Memory modules have one or more mating electrical contacts that couple with one or more sockets attached to the motherboard. Memory modules stand upright and away from the motherboard either at an angle or perpendicular to the motherboard surface. This allows for the attachment of many more memory chips than would be permitted if each chip were mounted directly to the motherboard. Memory modules also permit easy and rapid assembly/disassembly to the motherboard.
Commonly, more than one memory chip is mounted onto the PCB that makes up the memory module. Memory chips may be mounted on only one side of the PCB or on both sides. The memory chips are mounted such that they lie flat against the PCB. Memory chips come in a variety of sizes and shapes, but commonly, only memory chips of one type are used for each type of memory module. Since the same type of chip is used on a particular memory module, the mounted chips extend substantially the same distance above the surface of the PCB. Therefore, the back surface of one memory chip is substantially coplanar with adjacent chips on the same side of the PCB, the significance of which will be discussed below.
Advancements in memory components continuously focus on increased access speed and larger storage capacity in a smaller package. Inevitably, these advancements come in the form of memory chips that contain more circuits operating at higher speeds and mounted on smaller boards. In some types of memory modules, all of the memory chips on the PCB operate at substantially the same wattage and access rates such that the chips generate substantially the same heat. The chips on more advanced memory modules may operate at different wattage and at different access rates such that each chip produces different levels of heat at different times. The dissipation of excess heat becomes even more challenging as memory modules become faster and smaller.
In certain memory module configurations, especially for memory modules where one chip produces a different localized heat output as an adjacent chip, it is advantageous to manage this heat by spreading the heat over the entire memory module using a heat transfer apparatus. A common heat transfer apparatus used in the art is sheet metal which is placed overtop the backs of the memory chips and riveted to the PCB via holes in the board. Since that same type of chip is used on specific types of memory modules, the back surface of the chips on one side of the memory module are substantially coplanar. Therefore, a substantially flat piece of sheet metal will contact the back surface of all of the memory chips on a particular side of the memory module. If memory chips are mounted on both sides of the memory module, a second piece of sheet metal is used in similar fashion. The sheet metal acts to spread or distribute the heat produced by the chips over all of the chips on a particular side of the memory module resulting in a substantially even distribution of heat among the memory chips. The sheet metal also augments the dissipation of heat produced by the chips by exposing a larger surface to the environment.
There are drawbacks to the current heat transfer apparatus devices. The current heat transfer apparatuses require riveting the sheet metal to the PCB card. This requires that a number of holes be incorporated on the PCB card, which, among other things, takes up valuable space on the PCB card that could be used for other electrical components. Further, it is very difficult to access or replace the memory chips from the PCB once the sheet metal is riveted in place. Also, it is very difficult to reposition the heat transfer apparatus, for example during manufacturing, once riveting takes place. Further, uneven stress at the rivet locations may lead to an uneven contact between the chips and the sheet metal and unsatisfactory structural properties.
Another drawback of the present art involves the constant striving for component miniaturization present in the computer art. It is desired that the size of the memory module be made smaller yet retain the same or more memory capacity. Therefore, as the PCB card is made smaller while comprising the same number of memory chips, there is less room for a full compliment of mounting holes available for mounting the heat transfer apparatus as is available in a standard height memory card. Hence, a standard heat transfer apparatus can not be ideally utilized on shorter memory modules.
In addition, the present heat transfer apparatus is limited in its ability to act as a heat sink to dissipate the thermal energy to its environment. Further improvements are needed to improve the heat dissipation while retaining a compact size as well as to provide for disassembly.
Accordingly, there is a need for improved heat transfer apparatus and methods that address these and other shortcomings of the current art.