Abstract:
The present invention relates to circuit boards with radially arrayed components. One specific embodiment is a memory circuit board with memory components, such as, for example, DRAM chips, radially arrayed around a central point. The present invention also relates to stacking and connecting multiple circuit boards with radially arrayed components. Another embodiment of the invention involves methods of preparing radially arrayed components on a circuit board module with substantially equidistant paths to the components.

Description:
RELATED APPLICATIONS 
   The present application claims the benefit under 35 U.S.C. § 119(e) of U.S. provisional application Serial No. 60/643,128, filed on Jan. 12, 2005, entitled “Radial Circuit Board and System,” which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to circuit boards and more particularly to circuit boards with radially arrayed components. One specific embodiment is a circuit board with memory components, such as, for example, DRAM chips, radially arrayed around a central point. 
   BACKGROUND OF THE INVENTION 
   Designers of computer circuit boards contend with constraints relating to the length and path of lines connecting the various chips on the circuit board. In many circuit board applications there is a need to have data arrive at various chips at the same time during a data transfer. As the speed and data transfer rates increase and the size of chips decrease, this problem becomes more pronounced. Designers of computer memory boards are particularly hard pressed to assure that the data, address and control lines have uniform length between the memory chips and the various control chips. To ensure that data arrives at one chip in sync with data arriving at other chips, designers are often constrained to design data paths that are not the most direct path. 
     FIG. 1  provides a view of a typical computer memory board  10 . In the typical memory board  10 , memory chips  17  are arrayed in a linear pattern with control chips  19  located near the center. In order to assure that data is transferred on and off of the board in a coordinated pattern, the data lines from all of the chips to the control chip at the center of the board must be of approximately equal length. Thus, the lines connecting the outer most chips  17 A must be the same lengths as the lines connecting the inner chips  17 B. This need to have substantial uniformity in the length of the lines from all of the memory chips  17 , whether they are the outer chips  17 A, the inner chips  17 B or otherwise, complicates the design and function of the board  10 . The extra long lines in the current configuration waste precious board space and generate unnecessary and problematic heat. Furthermore, the lines to memory chips  17 B that are close to the control chip  19  may require the line to zig zag back and forth in order to increase the path length. 
   SUMMARY OF THE INVENTION 
   The present invention relates to circuit boards, and more particularly to circuit boards with radially arrayed components. One specific embodiment is a circuit board module comprising a connector; a plurality of components radially arrayed substantially equidistant around the connector; and an array of equidistant electrical connections positioned between the connector and the components. The components may be memory chips such as DRAM or SRAM. The circuit board module may also comprise at least one input-output device, wherein the array of substantially equidistant electrical connections connects the connector and the input-output device; and a second array of substantially equidistant electrical connections positioned between the input-output device and the components. The control chip may be fully buffered. The input-output device may comprise a plurality of control chips. The circuit board module may further comprise alignment pins positioned on the circuit board module. The connector may comprise a connector with pressure pins or a male/female connector arrayed on the bottom of the circuit board module. The circuit board module may further comprise a pressure pin pad array or a second male/female connector positioned on the top of the circuit board module configured to connect with the pressure pin connector of a second circuit board module. 
   The circuit board module of the previous embodiment may further comprise a post mechanically connected to a second circuit board with a predetermined cross-sectional shape and the circuit board module may have a center aperture that is congruent with a peripheral edge of the predetermined cross-sectional shape of the post. The center aperture may have a first and second set of electrical contacts at its peripheral edge. The first and second set of electrical contacts may be configured such that when the circuit board is placed over the post so that its aperture is around the post, the first and second electrical contacts detachably connect to each other and provide an electrical connection and mechanical connection for the circuit board to the post. The post may include electrical connections between the second contacts and the second circuit board. This post may also have at least one conduit for the passage of air through it. This conduit may have a first opening for injection of air and at least one opening adjacent to the second set of electrical contacts to allow passage of air from the conduit and over the circular board. 
   Another embodiment of the present invention is a stackable memory system comprising a circuit board and a plurality of circuit board modules. In this embodiment, the one or more components on the circuit board modules are memory chips. These circuit board modules are adapted to communicate with the circuit board via the connectors on each circuit board module. These circuit board modules may be circular or of any geometric shape. The connectors of this embodiment may comprise a post mechanically connected to the circuit board with a predetermined cross-sectional shape comprising at least one set of electrical contacts and each circuit board module may have a center aperture that is congruent with a peripheral edge of the predetermined cross-sectional shape of the post and with at least one set of electrical contacts in contact with the set of contacts on the post. 
   Another embodiment of the present invention comprises a circuit board with a circular board with memory chips disposed in a circular array around a center of the circular board, an apparatus for connecting the circular board to another circuit board; an input-output device on the circular board located in a position that is approximately equal distant from each of the memory chips; a first array of equidistant electrical connection lines between the input-output device and the memory chips; and a second array of electrical connection lines between the input-output device and the apparatus for connecting the circular board to the circuit board. The apparatus for connecting the circular board to a circuit board may comprise a post mechanically connected to the circuit board with a predetermined cross-sectional shape; and the circular board having a center aperture that is congruent with a peripheral edge of the predetermined cross-sectional shape of the post. The center aperture may have a first set of electrical contacts and the post having a second set of electrical contacts at its peripheral edge, the first and second set of electrical contacts being configured such that when the circular board is placed over the post so that its aperture is around the post, the first and second electrical contacts detachably connect to each other and provide an electrical connection and mechanical connection for the circular board to the post. The post may provide electrical connections between the second connection and the circuit board. This post may also have at least one conduit for the passage of air through it. The at least one conduit may have a first opening for injection of air and at least one opening adjacent to the second set of electrical contacts to allow passage of air from the conduit and over the circular board. 
   Another embodiment of the present invention is a method of manufacturing a circuit board with radially arrayed components. This method may include, for example, the steps of providing a circuit board module with a connector, placing or disposing components radially about the connector, and then electrically connecting the components with the connector. The method may further include, for example, providing a main circuit board with a connector and connecting the main circuit board with the circuit board module. A second circuit board module may also be stacked upon the first circuit board. A third, fourth, and fifth circuit board modules etc. may also be stacked. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a face view of a prior art memory board. 
       FIG. 2  is a top plan view of one example of a embodiment of the present invention. 
       FIG. 3  is a perspective view of an embodiment of a circular memory board of  FIG. 2  including a post that connects it to a computer circuit board. 
       FIG. 4  is top plan view of another embodiment of the present invention. 
       FIG. 5  is a perspective view of an embodiment of a circular memory board of  FIG. 4  attached to a post that connects it to a computer circuit board. 
       FIG. 6  is a side view of an embodiment of several circular memory boards connected to a post that connects them to a computer circuit board. 
       FIG. 7  is a view a center post according to another embodiment of the present invention. 
       FIG. 8  is a view of an embodiment of a post of  FIG. 7  along line VIII-VIII. 
       FIG. 9  is a cross-sectional view along line XI-XI of  FIG. 7 . 
       FIG. 10  is a top plan view of an embodiment of the present invention with components disposed on a circuit board. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   One of the primary advantages of the design of the memory board of the present invention is that many, all, or substantially all of the data, address and control lines may be of substantially equal length. This ensures, for example, that each memory chip or component can receive data at nearly the same time without the need to add what would be unnecessary length to the various data paths. One of the more difficult problems in designing a memory board is assuring that the data and the control lines, connected to each memory chip or component, are approximately the same lengths. Maintaining the same length of the data lines is useful, for example, so that during a read or write operations all of the bits of information accessed or saved on the memory chip move over the same distance and arrive at the desired destination at substantially the same time 
   One embodiment of the present invention is a circular memory board  20 , shown in  FIG. 2 . Memory chips  27  may be located radially in a circle around the surface of the memory board  20 . Control chips  29 , for example, can be located around the center opening and post connector  21  of memory board  20 . A circular memory board or disc  20  may be, for example, connected to a computer mother board through a center post or support such as that shown in  FIG. 3 . In such an embodiment data paths, i.e. first array of connections  110 , from the center opening and post connector  21  to control chips  29  may, for example, be of substantially equal length. Furthermore, data paths, i.e. second array of connections  111 , from control chips  29  to memory chips  27  may likewise, for example, be of substantially the same length. 
     FIG. 3  shows, for example, post  31  that may be attached to a computer circuit board  34 . The data, address and control lines may, for example, pass from the computer circuit board through or on post or support  31  to various memory boards  30  that may be detachably connected to the post  31  to a computer circuit board  34 . Circuit board  34 , which only appears in a cut away view in  FIG. 3 , may be a standard computer motherboard of a desktop computer, the main circuit board of a portable computer or other circuit boards used in any electronic equipment. 
     FIG. 4  provides a view of another embodiment of a circular memory board  40  of the present invention. In  FIG. 4 , memory chips  47  may again be arranged in a circle around the center of the board. Memory chips  47  can be positioned, for example, at approximately an equal distance from the center opening and post connector  41 . Control chips  49  may also be positioned around the center opening and post connector  41 . One difference between the memory board  40  of this embodiment and that shown in  FIG. 2  is that the center opening and post connector  41  is triangular in shape and thus may be attached to, for example, a triangular center post or support as shown in  FIG. 5 . 
   In  FIG. 5 , for example, post  51  may be attached, for example to a computer circuit board  54  and the data, address and control lines may, for example, pass from the computer circuit board  54  through or on post  51  to each memory board  50  attached to post  51 . Here again computer circuit board  54 , which only appears in a cut away view in  FIG. 5 , may be, for example, a standard computer motherboard of a desktop computer, main circuit board of a portable computer or other circuit board. Alternatively, an embodiment of this invention may include posts  51  with a square, rectangular, or any other acceptable shape. 
   The circuit boards in these embodiments may be constructed in the same or similar fashion as typical circuit boards. For example, they may be constructed with one or more of various configurations such as multi-layered with alternating conductive layers, conductive paths, and vias between the layers. At least one layer may provide power and ground. These boards may also be fabricated with alternating conductive and prepreg layers. Any type of circuit board may be used as a radial circuit board without deviating from the embodiments of the invention. 
     FIG. 6  shows a side view of a stack of three radial circuit boards  60  around a center support  61 . These three radial circuit boards each have a variety of chips  67  disposed thereon, including, for example, memory chips. Center support  61  electrically connects the radial circuit boards  60  to the motherboard  64  of, for example, a computer. The center aperture may have first array of connections  115  and a second array of connections  116  at its peripheral edge. In one embodiment, for example, the actual height of center post  61  with circular memory boards attached to it may be an inch or less in height. In other embodiments the height of the center post  61  may be over one inch. Furthermore, any number of radial circuit boards  60  may be stacked. For example, four, five or six radial circuit boards may be stacked around a center post  61 . 
     FIG. 7  is a raised view of one of the faces of the post  71  in  FIG. 4 .  FIG. 7  shows openings  73  arranged down the face of the post  71 . In this specific embodiment, center post  71 , for example, may have a hollow interior. Openings  73  allow air to flow into and out of the hollow center of post  71 . Providing a hollow core or interior with openings  71 , for example, will allow air injected into the core  71  to pass out through openings  73 , cooling the memory boards attached to center post  71 . In order to enhance the flow of air out across the memory boards attached to post  71 , fins may be included within the post to facilitate airflow from a hollow post. 
     FIG. 8  shows a top cross-sectional view of a center post  81 , for example, like one cut along line VIII-VIII of  FIG. 7 . The post  81  has a hollow center  82  that is visible in this figure. Vents  83  are also shown. These vents are positioned to allow air to flow onto stacked radial circuit boards to cool the components deposited thereon. The size and shape of the hollow center and the vents depend on the specific application. 
     FIG. 9  shows a side view of one of the vents  93  in a post  91 . This figure also shows a fin  95 , according to another embodiment of the invention, projected into the hollow core  92  located at the top of openings  93 . The fin  95  is designed to capture air and direct the air out over a circuit board. 
     FIG. 10  depicts another embodiment of the present invention. In  FIG. 10 , a square circuit board module  100  is shown. Memory chips  107  are disposed about the center of the board. The shape of the board in this embodiment is immaterial and may take any acceptable geometric shape (circle, square, triangle, polygon, diamond, etc.). This embodiment may also have a control chip  109  disposed in the center of the board with electrical connection lines arrayed from the central control chip to the various memory chips  107 . Each electrical connection line may be approximately equidistant from the control chip  109  to each component  107 . The control chip  109  of this embodiment may, for example, be fully buffered. The connector  106  of this embodiment allows a plurality of circuit board modules to be stacked upon each other. In such an arrangement, for example, each module may connect with a module above and below via the connector  106 . The circuit board module on the bottom of the stack may connect directly to another circuit board, such as, for example, a mother board. The connectors  106  may, for example, comprise male-female or pressure pin type connectors. This arrangement may also use, for example, alignment posts  108  to aid in aligning the circuit boards for connecting.  FIG. 10  shows these alignment posts  108  in the corners of the circuit board. The electrical connections from the control chip  109  to the components  107  may be approximately equidistant. Electrical connections from the connector  106  to the control chip  109  may also be approximately equidistant. 
   Although the invention has been particularly shown and described with reference to a number of embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made to it without departing from the spirit and scope of the invention.