COPLANAR CARD EDGE CONNECTOR

Abstract

An interconnect system includes a printed circuit board. The printed circuit board has a top surface and a bottom surface. The printed circuit board also has a first edge perpendicular to the top surface and the bottom surface. The printed circuit board also has a second edge perpendicular to the top surface and the bottom surface. The first edge surface and the second edge surface intersect at an angle that is not a straight angle. The interconnect system also includes a coplanar card edge socket on the printed circuit board. The socket has an upper section that interfaces with the top surface of the printed circuit board along the first and second edge surfaces of the printed circuit board. The socket also has a lower section that interfaces with the bottom surface of the printed circuit board along the first and second edge surfaces of the printed circuit board.

Description

BACKGROUND

[0001] The present invention relates to card edge connectors and, more particularly, to card edge connectors in environments with limited installation space.

[0002] A card edge connector is a type of connection between a printed circuit board (PCB) and a single component. The single component may take the form of a socket mounted on a second printed circuit board (PCB), and the card edge connector may be used as a connection between the PCB and the second PCB. In a typical card edge connector, contact traces (sometimes referred to herein as "card edge contacts") are placed directly on one or both sides of a printed circuit board (PCB) near or at the edge of the board. A corresponding socket may include a board-shaped opening (sometimes referred to herein as a "slot") and contacts therein, which may interface with the contact traces when the edge of the PCB is inserted into the slot. SUMMARY

[0003] Some embodiments of the present disclosure can be illustrated as an interconnect system for a card edge connector. The interconnect system includes a printed circuit board. The printed circuit board has a top surface and a bottom surface. The printed circuit board also includes a first edge surface perpendicular to the top surface and the bottom surface, and a second edge surface perpendicular to the top surface and the bottom surface. The first edge and the second edge intersect at an angle that is not a straight angle. The interconnect system also includes a coplanar card edge socket on the printed circuit board. The socket includes a top section that interfaces with the top surface of the printed circuit board along the first and second edge surfaces of the printed circuit board.The socket also includes a bottom section that interfaces with the bottom surface of the circuit board along the first and second edge surfaces of the circuit board.

[0004] Some embodiments of the present disclosure may also be illustrated as a printed circuit board. The printed circuit board has a top surface and a bottom surface. The printed circuit board also has a first edge surface perpendicular to the top surface and the bottom surface, and a second edge surface perpendicular to the top surface and the bottom surface. The first edge surface and the second edge surface intersect at an angle that is not a straight angle. The printed circuit board also has a first set of card edge contacts on the top surface along the first edge surface and a second set of card edge contacts on the top surface along the second edge surface. The printed circuit board also has a circuit chip module mounted on the top surface of the printed circuit board. The circuit chip module is partially surrounded by the first set of card edge contacts and the second set of card edge contacts.

[0005] Some embodiments of the present disclosure can also be illustrated as an interconnect system for a card edge connector. The interconnect system includes a first circuit board. The first circuit board has a first top surface and a first bottom surface. The first circuit board also has a first edge perpendicular to the first top surface and the first bottom surface. The first circuit board also has a second edge perpendicular to the first top surface and the first bottom surface. The first edge and the second edge intersect at a first angle that is not a straight angle. The interconnect system also includes a second circuit board. The second circuit board has a second top surface and a second bottom surface. The second circuit board also has a third edge perpendicular to the second top surface and the second bottom surface.The second circuit board also has a fourth edge that is perpendicular to the second top surface and the second bottom surface. The third edge and the fourth edge intersect at an angle that is a supplementary angle to the first angle. The second circuit board also has a first set of card edge contacts on the second top surface along the third edge. The interconnect system also includes a coplanar card edge socket on the first circuit board. The socket has an upper section that interfaces with the first top surface of the first circuit board along the first and second edges of the first circuit board. The socket also has a lower section that interfaces with the first bottom surface of the first circuit board along the first and second edges of the first circuit board.Inserting the third and fourth edges of the second circuit board into the coplanar card edge socket causes the first circuit board to lie in the same plane as the second circuit board. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A discloses an interconnect system for a card edge connector with a printed circuit board inserted into a coplanar card edge socket. Fig. Figure 1B discloses the connection system for a card edge connector after the circuit board has been inserted into the coplanar card edge socket. Fig. 2 discloses a coplanar card edge socket on a printed circuit board. Fig. 3 discloses a printed circuit board with card edge contacts on four edges of the printed circuit board and a module between the card edge contacts. Fig. 4A discloses an interconnect system for a set of card edge connectors having three circuit boards. Fig. Figure 4B discloses the interconnect system after a first circuit board has been inserted into a coplanar card edge socket on a second circuit board. Fig. Figure 4C discloses the interconnect system after a third circuit board has been inserted into a coplanar card edge socket on the first circuit board. DETAILED DESCRIPTION

[0006] Aspects of the present disclosure relate to electrical connector sockets, and in particular, aspects relate to card edge connector sockets. While the present disclosure is not necessarily limited to such applications, various aspects of the disclosure may be appreciated through a discussion of various examples using this context.

[0007] Common card edge connectors take the form of trace contacts (sometimes referred to herein as "card edge contacts") placed on the surface of a printed circuit board (sometimes referred to herein as a "PCB") designed to be inserted into a PCB-shaped slot in a socket. The socket typically contains contacts (sometimes in the form of contact pins) that interface with the trace contacts when the PCB is inserted into the slot.

[0008] Because a card edge connector enables a PCB itself to be directly inserted into a connector, card edge connectors can provide an efficient means for connecting the components of that PCB to other components of a larger system. For example, in some embodiments, an interconnect system for a card edge connector can allow a first PCB to be directly inserted into a socket extending directly from a second PCB. This enables connection between the components of both PCBs without relying on any connectors (e.g., cables) external to each PCB.

[0009] Some card edge connector interconnect systems place limitations on the designs of the printed circuit boards in and on which these connectors are embodied. Because the typical card edge contacts on a PCB are designed as a series of spaced-apart metal traces along one edge of a PCB surface, a card edge connector requiring a large number of connectors sometimes also requires a long span (i.e., length) of the PCB to be dedicated to a series of traces. For example, the relatively large width of a typical consumer-grade read-only memory ("RAM") module is largely dictated not by the amount of memory implemented by those RAM circuit chips, but rather by (1) the width required to lay out the metal traces to connect those chips to the overall system and (2) the wiring through the RAM module PCB required to connect the chips to those metal traces.

[0010] In some applications, even if the area on the edge of a card dedicated to the edge contacts would not impose undesirable constraints on the PCB design per se, the wiring from these connections to a PCB component can impose undesirable design constraints. For example, some circuit chip modules, such as memory modules and microchip processors, require that the length of each wire between the chip and each edge contact be of a similar, if not identical, length. This is because the chip requires that any signal sent on one of these wires reach each edge contact at the same time.This can become difficult when a chip connects many edge contacts distributed across a PCB edge, because the wiring between the closest edge contact and the chip can be significantly shorter than the wiring between the farthest edge contact and the chip. In some such situations, additional PCB space is designed to allow the wiring between a closest edge contact and the chip to take a much more tortuous route than the wiring between the farthest edge contact and the chip. This tortuous route can artificially lengthen the wiring to accommodate the wiring of other edge contacts, but can also require a very large amount of PCB space.

[0011] In some use cases, card edge connectors can also impose design constraints not only on the PCBs carrying the connectors (i.e., the card edge contacts and the corresponding card edge socket), but also on the overall system. For example, some card edge connector interconnect systems involve a first PCB with card edge contacts that are to be plugged into a socket extending from the surface of a second PCB, resulting in the first PCB (sometimes referred to as a "daughterboard") extending perpendicularly from the second PCB. In other words, the bottom and top surfaces of the first PCB are perpendicular to the bottom and top surfaces of the second PCB. As a result, the system into which the interconnect system is installed must be large enough to accommodate the width and depth of the first PCB in a first plane and the width and depth of the second PCB in the second plane.

[0012] Some card edge connector interconnect systems attempt to reduce the overall system space required for the connectors by stacking the connected PCBs. In other words, a first PCB may be inserted into a socket on a second PCB in a manner that results in the first PCB being parallel to, but above, the second PCB. For example, some low-profile RAM modules in laptop computers may utilize this or similar interconnect system designs. However, while such designs reduce the amount of space above the second PCB required to support the first PCB, such designs typically also impose limitations on the design of the second PCB.This is because the first PCB is typically stacked on top of and close to the second PCB, and thus the area on the second PCB below the first PCB cannot be used for components large enough to touch the first PCB. In other words, the width and depth of the first PCB must effectively be reserved on the surface of the second PCB, almost as if the first PCB were designed into the second PCB.

[0013] All of the above problems with card edge connectors are mitigated in use cases that require a large number of card edge contacts or a large daughterboard PCB. For example, interconnects requiring very high bandwidth or connectors for a high number of microprocessor pins may require a significant length of card edge to be reserved for card edge contacts and may also require a significant amount of PCB space to be dedicated to wiring for these contacts. Furthermore, large daughterboards such as pluggable VRM boards may not require a large number of contacts but can themselves have large PCBs to support the necessary power levels.

[0014] The above issues can sometimes limit the environments in which card edge connectors can be used. Furthermore, even if card edge connectors can be used in a particular environment, the benefits derived from them can be reduced or mitigated by the space required to support them. For example, environments where multiple servers are installed in small rooms are often very space-constrained, but also require high, reliable performance and high bandwidth. More space-efficient card edge connector systems can increase the benefits of card edge connectors derived from these systems.

[0015] Some embodiments of the present disclosure address the above problems by embodying card edge contacts on multiple adjacent edges of a PCB. For example, rather than arranging all card edge contacts on a single edge of a PCB, which requires the overall PCB design to embody at least one edge long enough for all of these contacts, some embodiments of the present disclosure distribute the contacts for a single connector at one corner of the PCB across two edges of the PCB.

[0016] Furthermore, some embodiments of the present disclosure utilize coplanar card edge connector systems, allowing a daughterboard to plug into a socket in a motherboard such that both PCBs are not only parallel but also in-plane with each other. In other words, the first PCB and the second PCB are parallel, but neither is on top of the other. In this way, the footprint of the daughterboard PCB does not need to be considered when selecting components to be placed on the surface of the motherboard PCB near the connector. Similarly, the daughterboard PCB can embody large components on both the top and bottom surfaces without affecting the surface of the motherboard PCB.

[0017] Finally, some embodiments of the present disclosure position chips or other modules connected to the card edge traces in a manner that reduces the differences in the lengths of the wires connecting the traces to the chips. For example, some embodiments of the present disclosure may position a chip near a card edge connector that forms a 90-degree angle, so that a line drawn between a set of contacts on one edge of the PCB and the module may intersect a line drawn between a set of contacts on another edge of the PCB and the module at a right angle.

[0018] Fig. 1A and Fig. 1B illustrates, for example, an example coplanar interconnect system 100 for a card edge connector spaced apart across two edges of each of the respective circuit boards. Fig. 1A discloses a first circuit board 102 before being inserted into a coplanar card edge socket 104 on a second circuit board 106.

[0019] The first printed circuit board 102 (sometimes referred to herein as "PCB 102") includes ten card edge contacts 108A, 108B, 108C, 108D, 108E, 108F, 108G, 108H, 108I, and 108J (collectively, "108") distributed along two edges 110 and 112 of the top surface of the PCB 102. In particular, the card edge contacts 108A to 108E form a first set of card edge contacts distributed along the edge 110, and the card edge contacts 108F to 108J form a first set of card edge contacts distributed along the edge 112. It should be noted that in practice, card edge contacts may often be distributed on both the top surface and the bottom surface of a PCB. While only contacts on the upper surface of the PCB 102 in the Fig. 1A, the PCB 102 may also include contacts on its lower surface.

[0020] Because the contacts 108 are distributed along two edges 110 and 112, the overall footprint of the first PCB 102 can be made smaller. For example, it may not be possible to fit all contacts 108 along a single edge 110 or 112 without making that edge longer. However, making one of the edges longer would also increase the overall footprint of the first PCB 102, making it too large for the overall system or at least increasing production costs.

[0021] It should be noted that the edges 110 and 112 are shown at a right angle to each other, but in other embodiments, other angles are possible. For example, the edges 110 and 112 could be offset at an obtuse angle (i.e., an angle greater than 90 degrees but less than 180 degrees), an acute angle (i.e., angle less than 90 degrees), or a super-obtuse angle (i.e., an angle greater than 180 degrees). The edges 110 and 112 could, in theory, be offset by any angle that is neither a straight angle (i.e., 180 degrees) nor no angle (i.e., 0 degrees). It should be noted that in some embodiments, the PCB 102 may also include a corresponding number of card edge contacts on the same two edges of the bottom surface of the PCB 102, but in Fig. 1A are not illustrated.

[0022] The card edge contacts 108 are oriented at an angle consistent with the direction from which the first PCB 102 is to be inserted into the card edge socket 104 on the second PCB 106. Specifically, rather than being oriented perpendicular to their respective edges, they are oriented at a 45-degree angle from their respective edges. For example, the card edge contact 108J is not oriented at a 90-degree angle from the edge 112, but rather at a 45-degree angle from the edge 112.

[0023] The first PCB 102 also includes an alignment cutout 114. The alignment cutout 114 may mate with an alignment tab within the socket 104 on the PCB 106. The interaction between the alignment cutout 114 and the corresponding alignment tab may not only help ensure that the first PCB 102 is inserted into the socket 114 such that the card edge contacts 108 properly connect to corresponding contacts within the socket 104, but may also prevent the first PCB 102 from shifting within the socket 104.

[0024] For the purpose of understanding disclosed Fig. 1B shows the interconnect system 100 after the first PCB 102 was inserted into the socket 104 on the second PCB 106. Because the card edge contacts 108 were distributed across two edges (edges 110 and 112) of the PCB 102 rather than a single edge, the PCB 102 was able to be formed into a smaller footprint corresponding to a cutout in the second PCB 106. This can significantly reduce the overall space required to support the interconnect system 100 on both the first PCB 102 and the second PCB 106. Furthermore, because the interconnect system 110 is a coplanar design, the first PCB 102 and the second PCB 106 are parallel and in the same plane with each other. This can also significantly reduce the overall space in the system required to support the combination of the first PCB 102 and the second PCB 106.

[0025] It should be noted that in practice, some portions of the PCB 102 may not be exactly in the same plane as the PCB 106, even if these PCBs are considered "coplanar" for the purposes of this disclosure. For example, in some applications, the top surface of the first PCB 102 may be parallel to and in exactly the same plane as the top surface of the second PCB 106. This may occur, for example, when the opening in the socket 104 is the same size as the width (i.e., the thickness of the PCB 106). In some applications, the top surface of the first PCB 102 may be in a slightly different plane than the second PCB 106. This may occur, for example, when the PCB 102 and the PCB 106 are of different thicknesses and when the opening in the socket 104 is smaller or larger than the thickness of the PCB 102.In these applications, the majority of the thicknesses of PCBs 102 and 106 may still overlap and lie within the exact same plane. Thus, the PCBs themselves are still considered to be in the same plane and thus "coplanar" for the purposes of this disclosure.

[0026] For the sake of complete illustration, Fig. 2 illustrates an example coplanar card edge socket 202 on a circuit board 204. The socket 202 may, in some embodiments, be similar to the socket 104 of Fig. 1A and Fig. 1B.

[0027] The socket 202 includes an upper section 206 that interfaces with the upper surface 208 of the printed circuit board 204 (sometimes referred to herein as "PCB 204") along a first edge 210 and a second edge 212 of the PCB 204. The upper section 206 may be structurally connected to the upper surface 208 of either the edge surfaces along the first edge 210 and the second edge 212, or any combination thereof. The socket 202 also includes a lower section 214 that interfaces with a lower surface (in Fig. 2) of the PCB 204 along the first edge 210 and the second edge 212. Like the upper section 206, the lower section 214 may be structurally connected to the lower surface of either the edge surfaces along the first edge 210 and the second edge 212, or any combination thereof. While the upper section and the lower section are illustrated as physically separate components that together form the socket 202, in some embodiments, the upper section and the lower section may be physically connected to each other before or after they are attached to the PCB 204.

[0028] The socket 202 includes an alignment tab 216 that can interact with an alignment cutout in a PCB that is inserted into the socket 202. This alignment cutout can be similar to the alignment cutout 114 of Fig. 1. The interaction between the alignment tab 216 and this alignment cutout can prevent the PCB from shifting within the socket 202. Although in Fig. 2, in some embodiments, the socket 202 may include other structures configured to align, guide, and secure a PCB within the socket 202. For example, the two ends of the socket 202 farthest from the alignment tab 216 may include guides configured to promote insertion of a PCB into the socket 202 in the correct position and orientation. These guides may also include a locking mechanism that locks the PCB into the socket 202 once it is fully inserted.

[0029] Although also in Fig. 2, the socket 202 may also include contacts on one or both of the upper section 206 and the lower section 214. These contacts may take a variety of forms (e.g., pins, springs, traces) and may correspond to card edge contacts on a PCB inserted into the socket 202.

[0030] Because the opening of socket 202 is slightly narrower than the width of PCB 204, a PCB inserted into socket 202 is slightly thinner than PCB 204. Therefore, the top surfaces of the two PCBs are not exactly in the same plane, while the two PCBs themselves are still considered parallel and in the same plane. However, the PCBs are still considered "coplanar" for the purposes of this disclosure.

[0031] On the other hand, in some embodiments, the opening of the socket 202 may be the same size as the thickness of the PCB 204. In these embodiments, a PCB inserted into the socket 202 may effectively be exactly the same thickness as the PCB 204. Thus, in these embodiments, the top (and bottom) surfaces of the two PCBs may lie exactly within the same plane.

[0032] As noted above, some embodiments of the present disclosure include a module surrounded or partially surrounded by one or more card edge connectors. This can reduce the difference in wire lengths between the card edge contacts and the module, thus reducing the need to reserve PCB space for convoluted wire routing of wires that would otherwise be too short.

[0033] Fig. Figure 3 discloses a printed circuit board 300 with card edge contacts on four edges of the board and a module between the card edge contacts. The printed circuit board 300 (sometimes referred to herein as "PCB 300") includes four sets of card edge contacts: 302A, 302B, 304A, and 304B. Sets of card edge contacts 302A and 302B (collectively, "302") are part of a first card edge connector, and sets of card edge contacts 304A and 304B (collectively, "304") are part of a second card edge connector.

[0034] In particular, the set of card edge contacts 302A is located on the top surface of the PCB 300 along an edge 306, and the set of card edge contacts 302B is located on the top surface of the PCB 300 along an edge 308. Inserting the edges 306 and 308 of the PCB 300 into a corresponding socket (e.g., a coplanar card edge connector socket) can cause the contacts within sets of contacts 302 to connect with corresponding contacts within the socket. Similarly, inserting edges 310 and 312 into another corresponding socket can cause the contacts within sets of contacts 304 to connect with corresponding contacts within the socket.

[0035] The PCB 300 includes a module 314. The module 314 may be, for example, a microprocessor chip, a memory chip, a chipset, or another type of computer chip module. The set of contacts 302 partially surrounds the module 314 because the set of contacts 302A is located on a first edge of the PCB 300 (the edge 306) closest to a first edge of the module 314, whereas the set of contacts 302B is located on a second edge of the PCB 300 (the edge 308) closest to a second edge of the module 314. Similarly, the set of contacts 304 also partially surrounds the module 314 because the set of contacts 304A and the set of contacts 304B are similarly arranged on the edges 310 and 312.

[0036] Each set of contacts 302A, 302B, 304A, and 304B has a corresponding set of wire traces extending from each contact to the module 314. Specifically, the set of contacts 302A has a set of wire traces 316A, the set of contacts 302B has a set of wire traces 316B, the set of contacts 304A has a set of wire traces 318A, and the set of contacts 304B has a set of wire traces 318B. Note that each trace in the sets of wire traces 316A, 316B, 318A, and 318B is of equal length, as illustrated, because the contacts in the sets of contacts 302 and 304 surround the module 314.

[0037] Because of this equal length, the module 314 could, for example, communicate with the components of another PCB through the contacts in the sets of card edge contacts 302, without the negative design constraints of (1) increasing the length of a single edge of the PCB 300 to provide sufficient length for all of the contacts in the sets of card edge contacts 302, and (2) increasing the overall footprint of the PCB 300 to allow for tortuous wiring between the sets of card edge contacts 302 to avoid uneven timing. This may, for example, enable higher performance through the corresponding card edge connection in a smaller interconnect system.

[0038] It should be noted that the PCB 300 is illustrated as having a tapered shape. Specifically, while edges 306 and 308 intersect at a 90-degree corner, and edges 310 and 312 do so as well, the other two corners of the PCB 300 are not present. This tapered shape may, for example, allow the PCB 300 to interact with guide components in a corresponding socket, as shown in Fig. 4A and Fig. 4B. Furthermore, this tapered shape may reduce the part cost of the PCB 300 and allow the PCB 300 to be installed within physically smaller environments.

[0039] It should also be noted that for clarity, PCB 300 is illustrated as including two duplicate card edge connectors. However, in some embodiments, a similar PCB layout may include a single card edge connector (e.g., sets of contacts 302) partially surrounding module 314. Further, while the card edge connectors associated with sets of contacts 302 and 304 are duplicated as illustrated, in some embodiments, a similar PCB may embody two or more different card edge connectors. For example, a similar PCB may include a module similar to module 314 and sets of contacts similar to sets of contacts 302, but along edges 310 and 312, the PCB may include a card edge connector with fewer traces or traces according to a different standard (e.g., Peripheral Component Interconnect Express).In some embodiments, one or both sets of trace contacts 302 and 304 may be replaced by a card edge socket, which may be configured to receive a PCB card edge connector.

[0040] Fig. 4A through 4C illustrate an interconnect system 400 for a set of card edge connectors that can be used to interconnect three printed circuit boards 402, 404, and 406. The PCBs 402 through 406 can represent various types of system components, but in one illustrative example, the PCB 402 can represent a backplane with a connection to a larger server system, the PCB 404 can represent a daughterboard with a processor that can be added to the system (e.g.,an add-in central processing unit, a graphics processing unit, a data processing unit, or an application processing unit), and the PCB 406 may represent a second daughter board with resources needed to operate the processor on the PCB 404 (for example, a voltage regulation module, a volatile memory module such as RAM; a non-volatile memory module; a security sensor or IoT sensor module; a smart key module for a security system).

[0041] The PCB 402 includes a coplanar card edge socket 408. The socket 408 is in a 90-degree form factor, meaning it has two sections offset from each other at an angle of 90 degrees: a section 410 that interfaces with the top surface of the PCB 402 along a first edge of the PCB, and a section 412 that interfaces with the top surface of the PCB 402 along a second edge of the PCB. For this reason, the socket 408 is configured to interface with a card edge connector that also has two edges offset from each other at an angle of 90 degrees. Note that in some embodiments, sections 410 and 412 are actually physically separate components that may be physically attached to each other.In some embodiments, socket 408 may also have separate lower sections that interface with a lower surface of PCB 402, where sections 410 and 412 may be considered "upper sections." In some embodiments, sections 410 and 412 may be a continuous component, but may still be referred to as separate sections herein for clarity.

[0042] Socket 408 also includes alignment guides 414A and 414B. Alignment guides 414A and 414B (collectively, "414") may be configured to interface with an edge connector on a tapered PCB (e.g., PCB 404) to promote the edge connector being inserted into socket 408 in the correct position. In some embodiments, the alignment guides may also help lock the PCB in place when the edge connector is fully inserted into socket 408.

[0043] The PCB 404 includes an edge connector distributed along two edges of the PCB 404. Specifically, the edge connector includes a set of card edge contacts 416A and a set of card edge contacts 416B (collectively, "416"). The set of contacts 416A is configured to interface with a corresponding set of contacts 416B within the section 410 of the socket 408, whereas the set of contacts 416B is configured to interface with a corresponding set of contacts within the section 412 of the socket 408.

[0044] The PCB 404 also includes a circuit module 418. The circuit module 418 may, for example, be a processor that can be added to a system to which the PCB 402 is connected. The circuit module 418 may be configured to route signals through wire traces to the contacts within the sets of contacts 416 and then to a card edge connector socket into which the PCB 404 is inserted.

[0045] The PCB 404 also includes a coplanar card edge socket 420. Similar to socket 408, socket 420 is in a 90-degree form factor. However, the form factors of sockets 408 and 420 differ from the perspective of a connector inserted into these connectors. While socket 408 forms a concave opening, socket 420 forms a convex opening. In other words, from the perspective of a connector inserted into socket 408, socket 408 forms an angle less than 180 degrees (i.e., 90 degrees). In other words, from the perspective of a connector inserted into socket 420, however, socket 420 forms an angle greater than 180 degrees (i.e., 270 degrees).

[0046] The PCB 406 includes sets of card edge contacts 422A and 422B (collectively, "422"). The sets of contacts 422 form a card edge connector that can be used to connect the PCB 406 to a card edge socket (e.g., the card edge socket 420).

[0047] Fig. 4B illustrates the interconnect system 400 after the card edge connector on the PCB 404, which is constructed from sets of contacts 416, has been inserted into the socket 408 on the PCB 402. As illustrated, the socket 408 is a coplanar socket, and thus the PCBs 402 and 404 are now in the same plane. In other words, a top surface of the PCB 402 is in the same plane as a top surface of the PCB 404. In some embodiments, the PCBs 402 and 404 may be in the exact same plane (e.g., if the socket 408 has the same width as the width of the PCB 402), but in other embodiments, the top surfaces of the PCBs 402 and 404 may be in slightly different planes (e.g., if the opening of the socket 408 is slightly larger or slightly smaller than the width of the PCB 402). In these embodiments, the majority of the widths are likely to overlap (i.e.,The thicknesses (i.e., the thicknesses) of PCBs 402 and 404 are still referred to as "coplanar" for the purposes of this disclosure. In typical embodiments, even if the top surfaces of PCBs 402 and 404 lie in slightly different planes, the middle layers of PCBs 402 and 404 may still lie in exactly the same plane.

[0048] Fig. Figure 4C illustrates the interconnect system 400 after the card edge connector of the PCB 406, which is constructed from sets of contacts 422, has been inserted into the socket 420 on the PCB 402. Similar to the socket 408, the socket 420 is, as illustrated, a coplanar socket. Thus, the PCBs 402, 404, and 406 are now all in the same plane with each other. As discussed with respect to Fig.4B, the top surfaces of 402, 404, and 406 may still be in slightly different planes, the majority of the widths of PCBs 402, 404, and 406 are likely to overlap, and thus PCBs 402, 404, and 406 are still considered to be in the same plane (i.e., coplanar) for the purposes of this disclosure.

[0049] The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope of the described embodiments. The terminology used herein has been chosen to best explain the principles of the embodiments, practical application, or technical improvement over technologies found in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

[1] Connection system for a card edge connector, the connection system comprising: a printed circuit board that has: an upper surface and a lower surface; and a first edge surface perpendicular to the upper surface and the lower surface, and a second edge surface perpendicular to the upper surface and the lower surface; wherein the first edge surface and the second edge surface intersect at an angle that is not a straight angle; a coplanar card edge socket on the circuit board, the socket comprising: an upper section connected as an interface to the upper surface of the circuit board along the first and second edge surfaces of the circuit board; and a lower section connected as an interface to the lower surface of the circuit board along the first and second edge surfaces of the circuit board. [2] The connection system of claim 1, wherein the first edge surface and the second edge surface intersect at a 90-degree angle. [3] The interconnect system of claim 1, wherein the coplanar card edge socket includes an alignment tab. [4] Printed circuit board comprising: an upper surface and a lower surface; a first edge surface perpendicular to the upper surface and the lower surface, and a second edge surface perpendicular to the upper surface and the lower surface, the first edge surface and the second edge surface intersecting at an angle that is not a straight angle; a first set of card edge contacts on the top surface along the first edge surface; a second set of card edge contacts on the top surface along the second edge surface; and a circuit chip module mounted on the top surface of the printed circuit board; wherein the circuit chip module is partially surrounded by the first set of card edge contacts and the second set of card edge contacts. [5] The circuit board of claim 4, wherein a first straight line from a first contact in the first set of card edge contacts to a center of the circuit chip module intersects a second straight line from a second contact in the second set of card edge contacts to the center of the circuit chip module at a 90-degree angle. [6] The printed circuit board of claim 4, wherein the first edge surface and the second edge surface intersect at a 90-degree angle. [7] The circuit board of claim 4, wherein the circuit chip module is a microprocessor chip. [8] The circuit board of claim 4, further comprising an alignment cutout. [9] The printed circuit board according to claim 4, wherein the printed circuit board has a tapered shape. [10] A printed circuit board according to claim 4, further comprising: a third edge surface perpendicular to the upper surface and the lower surface; a fourth edge surface perpendicular to the upper surface and the lower surface, the third edge surface and the fourth edge surface intersecting at an angle that is not a straight angle; a third set of card edge contacts on the upper surface along the third edge surface; and a fourth set of card edge contacts on the top surface along the fourth edge surface. [11] A printed circuit board according to claim 4, further comprising: a third edge surface perpendicular to the upper surface and the lower surface; a fourth edge surface perpendicular to the upper surface and the lower surface, the third edge surface and the fourth edge surface intersecting at an angle that is not a straight angle; and a coplanar card edge socket on the circuit board, the socket comprising: an upper section connected as an interface to the upper surface of the circuit board along the third and fourth edge surfaces of the circuit board; and a lower section connected as an interface to the lower surface of the circuit board along the third and fourth edge surfaces of the circuit board. [12] A connection system for a card edge connector, the connection system comprising: a first circuit board comprising: a first upper surface and a first lower surface; and a first edge surface perpendicular to the first upper surface and the first lower surface, and a second edge surface perpendicular to the first upper surface and the first lower surface; wherein the first edge and the second edge intersect at a first angle that is not a straight angle; a second circuit board comprising: a second upper surface and a second lower surface; a third edge perpendicular to the second upper surface and the second lower surface, and a fourth edge perpendicular to the second upper surface and the second lower surface, the third edge and the fourth edge intersecting at a second angle that is a supplementary angle to the first angle; and a first set of card edge contacts on the second upper surface along the third edge; and a coplanar card edge socket on the first circuit board, the socket comprising: an upper section connected as an interface to the first upper surface of the first circuit board along the first and second edges of the first circuit board; and a lower section connected as an interface to the first lower surface of the first circuit board along the first and second edges of the first circuit board; wherein insertion of the third and fourth edges of the second circuit board into the coplanar card edge socket causes the first circuit board to lie in the same plane as the second circuit board. [13] The connection system of claim 12, wherein the first and second edges intersect at an obtuse angle. [14] The connection system of claim 12, wherein the first and second edges intersect at an acute angle. [15] The interconnect system of claim 12, wherein the second circuit board comprises a non-volatile memory module. [16] The interconnect system of claim 12, wherein the second circuit board includes an alignment cutout. [17] The interconnection system of claim 12, wherein the second circuit board has a tapered shape. [18] The interconnection system of claim 12, wherein the second circuit board comprises: a fifth edge perpendicular to the second upper surface and the second lower surface; a sixth edge perpendicular to the second upper surface and the second lower surface; and a second set of card edge contacts on the second upper surface along the fifth edge. [19] The interconnection system of claim 12, wherein the second circuit board comprises: a fifth edge perpendicular to the second upper surface and the second lower surface; a sixth edge perpendicular to the second upper surface and the second lower surface; and a coplanar card edge socket on the second circuit board, the socket comprising: an upper section connected as an interface to the second upper surface of the second circuit board along the fifth and sixth edges of the second circuit board; and a lower section connected as an interface to the second lower surface of the second circuit board along the fifth and sixth edges of the first circuit board. [20] The interconnect system of claim 12, further comprising a third circuit board, the third circuit board having a card edge connector connected as an interface to a corresponding card edge connector on the second circuit board.

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