Board-to-board connector assembly for add-in cards

A board-to-board connector assembly includes a connector interposer between first and second connectors each having a connector housing holding contacts and having a card slot for interfacing with a circuit card edge of a corresponding add-in card. The connector housings have board guides configured to engage the add-in cards and guide mating therewith. The connectors have latches configured to latchably engage the add-in cards to secure the connector to the add-in cards. The connector interposer electrically interconnects the first contacts and the second contacts.

BACKGROUND OF THE INVENTION

The subject matter herein relates generally to board-to-board connector assemblies for add-in cards.

Electronic devices, such as computing devices, use communication systems to electrically connect and communicate data between various components of the system. For example, for high power computing devices, such as in hardware accelerators, general purpose GPUs, and the like, host circuit boards are provided with electrical connectors that allow add-in cards to be electrically connected into the system to enhance computing capabilities of the system. The add-in cards are electrically connected to the host circuit board through the electrical connectors on the host circuit board. The add-in cards have electrical components, such as processors, memories, and the like to enhance the capabilities of the system. However, the system is limited by the amount of data that can be communicated between the add-in card and the host circuit board.

Some known systems have been designed to network the add-in cards together to enhance the capabilities of the system even further. For example, secondary electrical connectors are provided on the add-in cards that are networked together through cable assemblies. Such systems are not without disadvantages. For instance, the systems provide hardware on the add-in cards for guidance and mating of plugs of the cable assemblies with the add-in cards. Such hardware occupies valuable board space on the add-in card and/or increases the envelope of the add-in card, which either increases the overall size of the system or reduces the density of the system by reducing the number of add-in cards that are able to fit within a given framework.

A need remains for a communication system that allows electrical interconnection of add-in cards in a reliable and cost effective manner.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a board-to-board connector assembly is provided including a first connector, a second connector and a connector interposer between the first connector and the second connector. The first connector has a first connector housing holding first contacts and having a first card slot. The first contacts are arranged at the first card slot for interfacing with a circuit card edge of a first add-in card. The first connector housing has a board guide configured to engage the first add-in card and guide mating with the first add-in card. The first connector has a first latch configured to latchably engage the first add-in card to secure the first connector to the first add-in card. The second connector has a second connector housing holding second contacts and having a second card slot. The second contacts are arranged at the second card slot for interfacing with a circuit card edge of a second add-in card. The second connector housing has a board guide configured to engage the second add-in card and guide mating with the second add-in card. The second connector has a second latch configured to latchably engage the second add-in card to secure the second connector to the second add-in card. The connector interposer electrically interconnects the first contacts and the second contacts.

In another embodiment, an add-in card assembly is provided for a communication system having a host circuit board. The add-in card assembly includes an add-in card having a primary circuit at a primary circuit card edge configured to be plugged into a primary card edge connector of the host circuit board of the communication system. The add-in card has an electronic component electrically connected to the primary circuit. The add-in card has a secondary circuit electrically connected to the electronic component and routed to a secondary circuit card edge. The add-in card assembly includes a board-to-board connector coupled to the secondary circuit at the secondary circuit card edge. The board-to-board connector has a first connector housing holding first contacts and having a first card slot receiving the secondary circuit card edge. The first contacts are arranged at the first card slot for interfacing with the secondary circuit at the secondary circuit card edge of the add-in card. The first connector housing has a board guide engaging the add-in card to guide mating of the first connector housing with the add-in card. The first connector has a first latch latchably engaging the add-in card to secure the first connector to the add-in card.

In a further embodiment, a communication system is provided including a host circuit board having a first card edge connector coupled to the host circuit board and a second card edge connector coupled to the host circuit board. The communication system includes a first add-in card coupled to the first card edge connector having a first circuit card edge and a second add-in card coupled to the second card edge connector having a second circuit card edge. The communication system includes a board-to-board connector assembly coupled to the first add-in card at the first circuit card edge and coupled to the second add-in card at the second circuit card edge to electrically connect the first and second add-in cards. The boar-to-board connector assembly includes a first connector, a second connector and a connector interposer between the first connector and the second connector. The first connector has a first connector housing holding first contacts and having a first card slot. The first contacts are arranged at the first card slot for interfacing with a circuit card edge of a first add-in card. The first connector housing has a board guide configured to engage the first add-in card and guide mating with the first add-in card. The first connector has a first latch configured to latchably engage the first add-in card to secure the first connector to the first add-in card. The second connector has a second connector housing holding second contacts and having a second card slot. The second contacts are arranged at the second card slot for interfacing with a circuit card edge of a second add-in card. The second connector housing has a board guide configured to engage the second add-in card and guide mating with the second add-in card. The second connector has a second latch configured to latchably engage the second add-in card to secure the second connector to the second add-in card. The connector interposer electrically interconnects the first contacts and the second contacts.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a front view of a communication system100in accordance with an exemplary embodiment.FIG. 2is a side view of the communication system100in accordance with an exemplary embodiment. The communication system100may be used in an electronic device or computing device. For example, the communication system100may be used for high power computing, such as in a hardware accelerator, a general purpose GPU, and the like. In an exemplary embodiment, the communication system100includes a host circuit board102having electronics thereon. The host circuit board102includes connectors, such as card edge connectors104for interfacing with multiple add-in card assemblies106.

In an exemplary embodiment, the add-in card assemblies106include board-to-board connector assemblies108to electrically connect various add-in card assemblies106to network the add-in card assemblies106. The board-to-board connector assemblies108provide communication paths between the add-in card assemblies106separate from the host circuit board102. The board-to-board connector assemblies108enhance processing capabilities of the communication system100by networking the add-in card assemblies106. In an exemplary embodiment, the board-to-board connector assemblies108are low profile. Optionally, the board-to-board connector assemblies108allow add-in card assemblies106to be electrically connected to multiple other add-in card assemblies106. In an exemplary embodiment, the board-to-board connector assemblies108are mounted directly to the add-in cards of the add-in card assemblies106to minimize components and interfaces between the components.

In an exemplary embodiment, the communication system100includes a chassis110holding the host circuit board102and the add-in card assemblies106. The chassis110may include panels112forming an enclosure. The host circuit board102may be coupled to the chassis110, such as coupled to a bottom panel of the chassis110. Optionally, the host circuit board102may be oriented horizontally at the bottom of the chassis110. The add-in card assemblies106may be located above the host circuit board102in various embodiments. For example, the add-in card assemblies106may be oriented vertically and stacked adjacent each other along the host circuit board102.

With reference toFIG. 2, the add-in card assembly106includes an add-in card120and one or more electronic components122mounted to the add-in card120. The electronic component122may be electrically connected to the host circuit board102through the card edge connector104. For example, a primary circuit card edge130of the add-in card120may be plugged into the card edge connector104. A primary circuit132may electrically connect the electronic component122with the primary circuit card edge130of the add-in card120.

The board-to-board connector assembly108may be electrically connected to a secondary circuit card edge134of the add-in card120. A secondary circuit136may electrically connect the electronic component122with the secondary circuit card edge134of the add-in card120.

In an exemplary embodiment, the add-in card assembly106includes a front panel124mounted to a front of the add-in card120. The front panel124may be coupled to the chassis110to present an interface for the add-in card120at the chassis110. For example, the front panel124may include a port126having an interface connector128. The interface connector128may be a socket connector, a header connector, a receptacle connector or another type of connector for mating with a mating connector, such as a plug connector. An interface circuit138may electrically connect the interface connector128with the electronic component122.

In an exemplary embodiment, the primary circuit card edge130is provided at a bottom140of the add-in card120and the secondary circuit card edge134is provided at a top142of the add-in card120. Optionally, the add-in card120may include multiple secondary circuit card edges134at the top142for interfacing with multiple board-to-board connector assemblies108along the top142. In an exemplary embodiment, the primary circuit card edge130includes a guide slot144to guide mating with the card edge connector104(shown in phantom inFIG. 2). The add-in card120includes contact pads146arranged along the primary circuit card edge130for mating with the card edge connector104. The contact pads146may be signal contacts, ground contacts, or power contacts. The signal contacts may be high speed signals, low speed signals and the like. The contact pads146may be defined by circuits of the add-in card120, such as circuits of the primary circuit132.

In an exemplary embodiment, the secondary circuit card edge134includes contact pads150at the circuit card edge134. The contact pads150may be provided on both sides of the add-in card120in various embodiments. In an exemplary embodiment, the secondary circuit card edge134includes a guide slot152to guide or position the board-to-board connector assembly108relative to the secondary circuit card edge134. Optionally, contact pads150may be provided on both sides of the guide slot152. In an exemplary embodiment, the add-in card120includes channels154at opposite ends of the secondary circuit card edge134. The channels154define the secondary circuit card edge134and separate the secondary circuit card edge134from flanking members156on opposite ends of the secondary circuit card edge134. The flanking members156may be provided between the various circuit card edges134. The channels154may be formed by removing material of the add-in card120, such as by using a router or other device to cut or remove material to form the channel154.

The channel154has an inner surface158extending along the circuit card edge134and an outer surface160extending along the flanking member156. Optionally, the inner surface158and/or the outer surface160may be generally perpendicular to the top142. In various embodiments, the inner surface158and/or the outer surface160at the top142may be chamfered to provide a lead-in to the channel154to guide the board-to-board connector assembly108into the channel154. In various embodiments, the inner surface158and/or the outer surface160may be stepped having one or more shoulders162. The inner surface158and/or the outer surface160may be used as a guide surface to guide mating of the board-to-board connector assembly108with the add-in card120. In an exemplary embodiment, the channel154includes a notch164at a bottom of the channel154. The notch164is formed under the flanking member156in the illustrated embodiment. In an exemplary embodiment, the notch164is used for latching the board-to-board connector assembly108directly to the add-in card120.

FIG. 3is a perspective view of the board-to-board connector assembly108in accordance with an exemplary embodiment. The board-to-board connector assembly108includes a first connector200, a second connector202and a connector interposer204between the first connector200and the second connector202. Optionally, the second connector202may be similar to, or even identical to, the first connector200, and like components may be identified with like reference numerals with or without the “first” or “second” identifiers, respectively.

In the illustrated embodiment, the connector interposer204includes wires206between the first and second connectors200,202. However, in alternative embodiments, the connector interposer204may include another type of interconnect, such as a flexible circuit, a printed circuit board, or another type of interconnect. In the illustrated embodiment, the connector interposer204electrically connects the first connector200to the second connector202. In other various embodiments, the connector interposer204may electrically connect the first connector200to one or more additional connectors and/or may electrically connect the second connector202one or more additional connectors.

The connector200includes a connector housing210holding contacts212(shown inFIGS. 4 and 5). The connector housing210has a card slot214(shown inFIG. 4) for interfacing with the circuit card edge134(shown inFIG. 2) of the add-in card120(shown inFIG. 2). The connector housing210has a board guide216configured to engage the add-in card120and guide mating with the add-in card120. The connector200has a latch218configured to latchably engage the add-in card120to secure the connector200to the add-in card120.

The second connector202similarly includes a second connector housing210holding second contacts212in a second card slot214and having a second board guide216and a second latch218. The connector interposer204electrically connects the first contacts212of the first connector200with the second contacts212of the second connector202. The connector interposer204extends between the first connector housing210of the first connector200and the second connector housing210of the second connector202.

FIG. 4is an end view of the connector200of the board-to-board connector assembly108in accordance with an exemplary embodiment.FIG. 5is a side view of the connector200of the board-to-board connector assembly108in accordance with an exemplary embodiment.

In an exemplary embodiment, the connector housing210of the connector200is a multi-piece housing including a connector body220and a cover222holding the connector body220. In alternative embodiments, the connector housing210is a single piece housing rather than a multi-piece housing. The connector body220holds the contacts212(FIG. 5) and defines the card slot214(FIG. 5) that receives the circuit card edge134(shown inFIG. 2) of the add-in card120(shown inFIG. 2). The connector body220extends between a front224and a rear226. The card slot214is open at the front224to receive the circuit card edge134. As depicted inFIG. 5, the card slot214extends along a longitudinal axis228between opposite ends230,232of the connector body220. The contacts212are arranged along the card slot214, such as based apart longitudinally the length of the card slot214. Optionally, the contacts212may be arranged on opposite sides234,236of the connector body220, such as on both sides of the card slot214to engage both sides of the circuit card edge134.

The cover222holds the connector body220, the latch218and defines the board guide216. In the illustrated embodiment, the board guide216includes a first support arm240and a second support arm242separated from the first support arm240by a gap244. The gap244is aligned with the card slot214. The gap244is configured to receive the add-in card120, such as the circuit card edge134and/or the flanking members156(shown inFIG. 2). The first support arm240is configured to engage a first side of the add-in card120and the second support arm242is configured to engage a second side of the add-in card120. In the illustrated embodiment, the support arms240,242extend forward of the front224of the connector body220. The support arms240,242are configured to engage the add-in card120prior to the connector body220receiving the add-in card120. The board guide216is used to guide the add-in card120into the card slot214of the connector body220. Optionally, the end of the board guide216may define a hard stop configured to engage the top edge of the add-in card120when fully loaded to position the connector body220relative to the add-in card120.

In an exemplary embodiment, latch218extends through the board guide216. For example, the latch218may be pivotably coupled to the cover222of the connector housing210. In an exemplary embodiment, the latch218includes an actuator250extending from a hub252and a latching arm254extending from the hub252. The actuator250extends to an exterior of the connector housing210to be accessed and actuated by an operator to release the latch218from the add-in card120to remove the connector200from the add-in card120. For example, the latch218may be pivoted to an unlatched or released position. In the illustrated embodiment, the latch218is actuated in a direction perpendicular to the longitudinal axis228. Optionally, the latch218includes a return spring256engaging the connector housing210to return the latch218to a latching position when the actuator250is released. In the illustrated embodiment, the return spring256extends from the actuator250. The return spring256may extend from the latching arm254or the hub252in other embodiments. The latching arm254includes a latching surface258configured to engage the add-in card120to latchably couple the connector200to the add-in card120. For example, the latching surface258may engage the outer surface160of the channel154, such as the notch164of the channel154(shown inFIG. 2) to latchably secure the connector200to the add-in card120. In an exemplary embodiment, the latching surface258is configured to directly engage the add-in card120to secure the connector200to the add-in card120.

In an exemplary embodiment, the connector interposer204includes a circuit board290the circuit board290includes a first surface292and a second surface294. In the illustrated embodiment, the wires206are terminated to the first surface292. For example, the wires206may be soldered to contact pads on the first surface292. The contacts212are terminated to the second surface294. For example, the contacts212may be through-hole or press-fit mounted to via of the circuit board290. In other various embodiments, the contacts212may be soldered to contact pads on the second surface294. The circuit board290is held in the cover222. Optionally, a portion of the cover222may be filled with material296to secure the wires206and/or the circuit board290in the cover222. For example, the material296may provide strain relief for the wires206. The material296may be a plastic material or a hot melt material. The material296may be injected into the cover222. The material296may be formed in place, such as an overmold material.

FIG. 6is a top view of the board-to-board connector assembly108in accordance with an exemplary embodiment showing the connector interposer204in the first connector200in phantom. The wires206extend into the connector housing210and are terminated to the circuit board290. For example, the wires206may be soldered to contact pads298on the first surface292of the circuit board290. The wires206are flexible to allow relative spacing between the first and second connectors200,202. The flexible wires206may allow the first connector200or the second connector202to be removed from the add-in card120without needing to remove the other connector200or202.

FIG. 7is a side view of the board-to-board connector assembly108mounted to the add-in card120in accordance with an exemplary embodiment.FIG. 8is an end view of the board-to-board connector assembly108mounted to the add-in card120in accordance with an exemplary embodiment. The connector housing210is mounted directly to the add-in card120at the circuit card edge134. The circuit card edge134plugs into the connector200. The connector200is supported directly on the add-in card120. The board guide216guides mating with the add-in card120and supports the connector200on the add-in card120. The latch218is located in the board guide216to directly engage the add-in card120. In the latched position, the latch218is received in the notch164(shown inFIG. 2) to secure the connector200to the add-in card120.

The board-to-board connector assembly108makes an electrical connection to the add-in card120across a single electrical interface with the circuit card edge134of the add-in card120. The communication system100does not provide a separate connector mounted to the add-in card120that the board-to-board connector assembly is mated to. Rather, the board-to-board connector assembly108mates directly to the circuit card edge134of the add-in card120. The mating guidance is provided by the interaction between the add-in card120and the board guide216. The latching is provided by the latch218directly engaging the add-in card120.

FIG. 9is a perspective view of a portion of the communication system100in accordance with an exemplary embodiment showing board-to-board connector assemblies308coupled to corresponding add-in card assemblies306. The add-in card assemblies306are similar to the add-in card assemblies106shown inFIGS. 1 and 2; however, the add-in card assemblies306are shaped differently to interface with the board the board connector assemblies308. The board-to-board connector assemblies308are similar to the board-to-board connector assemblies108shown inFIGS. 1 and 2; however, the board-to-board connector assemblies308may attach to the add-in card assemblies306differently. In an exemplary embodiment, the board-to-board connector assemblies308are mounted directly to the add-in cards of the add-in card assemblies306to minimize components and interfaces between the components.

The add-in card assembly306includes an add-in card320configured to be electrically connected to a card edge connector of a host circuit board. The add-in card320includes a circuit card edge334at a top342of the add-in card320. The board-to-board connector assembly308is electrically connected to the circuit card edge334of the add-in card320. The board-to-board connector assembly308is configured to be directly attached to the add-in card320at the circuit card edge334.

The board-to-board connector assembly308includes a first connector400, a second connector402and a connector interposer404between the first connector400and the second connector402. Optionally, the second connector402may be similar to, or even identical to, the first connector400, and like components may be identified with like reference numerals with or without the “first” or “second” identifiers, respectively.

In the illustrated embodiment, the connector interposer404includes wires406between the first and second connectors400,402. However, in alternative embodiments, the connector interposer404may include another type of interconnect, such as a flexible circuit, a printed circuit board, or another type of interconnect. In the illustrated embodiment, the connector interposer404electrically connects the first connector400to the second connector402. In other various embodiments, the connector interposer404may electrically connect the first connector400to one or more additional connectors and/or may electrically connect the second connector402one or more additional connectors.

The connector400includes a connector housing410holding contacts412(shown inFIG. 11). The connector housing410has a card slot (not shown) for interfacing with the circuit card edge334of the add-in card320. The connector housing410has a board guide416configured to engage the add-in card320and guide mating with the add-in card320. The connector400has a latch418configured to latchably engage the add-in card320to secure the connector400to the add-in card320.

In an exemplary embodiment, the connector interposer404includes a circuit board490having a first surface492and a second surface494. In the illustrated embodiment, the wires406are terminated to the first surface492. For example, the wires406may be soldered to contact pads498on the first surface492. The contacts412are terminated to the second surface494. For example, the contacts412may be through-hole or press-fit mounted to via of the circuit board490. In other various embodiments, the contacts412may be soldered to contact pads on the second surface494. The circuit board490is held by the connector housing410. Optionally, material may be molded over the wires406and/or the circuit board490to provide strain relief for the wires406.

The second connector402similarly includes a second connector housing410holding second contacts412in a second card slot and having a second board guide416and a second latch418. The connector interposer404electrically connects the first contacts412of the first connector400with the second contacts412of the second connector402. The connector interposer404extends between the first connector housing410of the first connector400and the second connector housing410of the second connector402.

FIG. 10is a perspective view of the add-in card320in accordance with an exemplary embodiment. In an exemplary embodiment, the circuit card edge334includes contact pads350at the circuit card edge334. In an exemplary embodiment, the add-in card320includes channels354at opposite ends of the circuit card edge334. The channels354define the circuit card edge334and separate the circuit card edge334from flanking members356on opposite ends of the circuit card edge334. The flanking members356may be provided between the various circuit card edges334.

The channel354has an inner surface358extending along the circuit card edge334and an outer surface360extending along the flanking member356. Optionally, the inner surface358and/or the outer surface360may be generally perpendicular to the top342. In various embodiments, the inner surface358and/or the outer surface360at the top342may be chamfered to provide a lead-in to the channel354to guide the board-to-board connector assembly308into the channel354. In various embodiments, the inner surface358and/or the outer surface360may be stepped having one or more shoulders. The inner surface358and/or the outer surface360may be used as a guide surface to guide mating of the board-to-board connector assembly308with the add-in card320. In an exemplary embodiment, the channel354includes a notch364at a bottom of the channel354. The notch364is formed under the flanking member356in the illustrated embodiment. In an exemplary embodiment, the notch364is used for latching the board-to-board connector assembly308directly to the add-in card320. For example, the notch364is configured to receive the latch418of the connector400(shown inFIG. 9).

FIG. 11is a perspective view of the add-in card assembly306showing a portion of the board-to-board connector assembly308mounted to the add-in card320.FIG. 12is a side view of a portion of the add-in card assembly306showing a portion of the board-to-board connector assembly308mounted to the add-in card320.

In an exemplary embodiment, the connector housing410of the connector400is a multi-piece housing including a connector body420and a cover422holding the connector body420. In alternative embodiments, the connector housing410is a single piece housing rather than a multi-piece housing. The connector body420holds the contacts412and defines the card slot (not shown) that receives the circuit card edge334(shown inFIG. 10) of the add-in card320(shown inFIG. 10). The cover422holds the latch418. In an exemplary embodiment, the cover422defines the board guide416. For example, in the illustrated embodiment, the board guide416includes a first support arm440and a second support arm442separated from the first support arm440by a gap444aligned with the card slot414to receive the add-in card320. The support arms440,442engage both sides of the add-in card320to support the connector body420on the add-in card320. In an exemplary embodiment, the latch418is pivotably coupled to the connector housing410. In an exemplary embodiment, the latch418includes an actuator450and a latching arm454having a latching surface458configured to engage the add-in card320to latchably couple the connector400to the add-in card320. For example, the latching surface458may engage the outer surface360of the channel354, such as in the notch364of the channel354. In an exemplary embodiment, the latch418is actuated in a direction parallel to a longitudinal axis411of the connector housing410. For example, the exposed end of the latch418at the top of the latch418may be pushed outward to actuate the latch418.

FIG. 13is a perspective view of a portion of the communication system100in accordance with an exemplary embodiment showing the board-to-board connector assemblies308coupled to corresponding add-in card assemblies306. In the illustrated embodiment, the connector interposer404is illustrated including a flexible circuit480rather than the individual wires406illustrated inFIG. 9. In the illustrated embodiment, the connector interposer404includes backer plates482,484configured to be coupled to the connector housings410of the first and second connectors400,402. The backer plates482,484provide a rigid substrate for securing the flexible circuit480to the contacts412of the first and second connectors400,402. For example, the contacts412of the first and second connectors400,402may include spring beams and the backer plates482,484may compress the flexible circuit480against the spring beams to create an electrical connection therebetween. The flexible circuit480may be electrically connected to the contacts412by other means in alternative embodiments. Rather than backer plates, the connector interposer404may include rigid circuit boards with the flexible circuit480therebetween.

FIG. 14is a perspective view of a portion of the communication system100in accordance with an exemplary embodiment showing the board-to-board connector assemblies308coupled to corresponding add-in card assemblies306. In the illustrated embodiment, the connector interposer404is illustrated as a circuit board488extending between the first and second connectors400,402. The circuit board488replaces the individual circuit boards490of the first and second connectors400,402and wires406illustrated inFIG. 9. The circuit board488eliminates interfaces between the first and second connectors400,402compared to using the wires406; however, the circuit board488is rigid and requires more precise positioning of the first and second connectors400,402compared to the embodiment utilizing the wires406. The circuit board488is terminated directly to the contacts412of the first connector400and the contacts412of the second connector402to create the electrical path between the add-in cards320.