Abstract:
The subject matter of this disclosure relates to a flexible circuit for carrying a signal between electrical components that includes boosting circuitry for mitigating the effects of signal degradation. More particularly the flexible circuit can carry a signal between a main logic board and an input/output board supporting input/output ports of a portable electronic device. The flexible circuit can be configured with bends in order to meet packaging constraints such as avoiding contact with components obstructing a direct path between connectors of the electrical components. Additional bends can also be included in the flexible that facilitate the assembly of the portable electronic device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application PCT/US2015/066637, with an international filing date of Dec. 18, 2015, entitled “FEATURES OF A FLEXIBLE CONNECTOR IN A PORTABLE COMPUTING DEVICE,” and claims the benefit of priority under 35 U.S.C §119(e) to U.S. Provisional Application No. 62/101,854, filed Jan. 9, 2015, entitled “FEATURES OF A FLEXIBLE CONNECTOR IN A PORTABLE COMPUTING DEVICE,” each of which is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    The described embodiments relate generally to internal connectors for an electronic device. In particular, the present embodiments relate to internal connectors taking the form of flexible circuits having shielded surface mounted electrical components. 
       BACKGROUND 
       [0003]    Many portable computing devices utilize internal connectors that carry signals to route communications between internal components of the portable computing devices. As portable computing devices continue to take advantage of new input/output (I/O) protocols that allow for increasingly rapid I/O communications, high-speed signals traveling between I/O interfaces and other internal components become more susceptible to signal degradation when compared to lower speed I/O interfaces. For example, USB 2.0 signals can be less susceptible to signal degradation than signals utilizing USB 3.0 protocols. One situation where signal degradation becomes an issue occurs when a first component requires connection to a second component offset a substantial distance from the first component. The signal degradation can be mitigated by boosting components that can be integrated within the first component or the second component in order to ameliorate the signal degradation. Unfortunately, packaging or other engineering constraints can prevent the integration of boosting components within the first or the second component. 
       SUMMARY 
       [0004]    This paper describes various embodiments that relate to flexible connectors that route communications between internal electrical components. 
         [0005]    A flexible connector assembly is disclosed. The flexible connector assembly can include a flexible substrate that includes a power layer and a data layer. The data layer and the power layer are separated at a bend region of the flexible substrate. The bend region has a geometry that includes at least two separate bends oriented in different directions, which cooperate to accommodate relative motion of components connected by the flexible connector in at least two dimensions. The flexible connector assembly can further include a first connector disposed on a first end of the flexible substrate and a second connector disposed on a second end of the flexible substrate. Further, circuitry for processing signals passing through the data layer is mounted to the flexible substrate and electrically coupled with both the power layer and the data layer. 
         [0006]    An electronic device is disclosed. The electronic device includes at least the following: a device housing; a port arranged along an exterior surface of the device housing that receives data and system power for the electronic device; and an electrical connector that routes data and power received at the data port to electrical components within the device housing, the electrical connector including a flexible substrate, and circuitry surface mounted to the flexible substrate that boosts the strength of data signals travelling through the flexible connector. 
         [0007]    A flexible connector is disclosed. The flexible connector includes a flexible substrate including a data layer and a power layer; an electrical assembly surface mounted to an exterior surface of the flexible substrate and in electrical contact with the data layer and the power layer; and electrical connectors positioned at opposite ends of the flexible substrate. The electrical assembly processes a signal routed through the data layer while data is being passed through the data layer. 
         [0008]    Other systems, methods, features and advantages of the embodiments will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the embodiments, and be protected by the following claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
           [0010]      FIG. 1A  shows a perspective view of a flexible circuit in accordance with the described embodiments; 
           [0011]      FIG. 1B  shows a cross-sectional view of a booster assembly of the flexible circuit depicted in  FIG. 1A ; 
           [0012]      FIG. 2A  shows a perspective view of a connector in a folded state at an end of the flexible circuit; 
           [0013]      FIG. 2B  shows a perspective view of the end of the flexible circuit in an unfolded state; 
           [0014]      FIG. 2C  shows an air gap between layers of the flexible circuit at the end of the flexible circuit; 
           [0015]      FIG. 3  shows a detailed view of another end of the flexible circuit; 
           [0016]      FIGS. 4A-4B  show top and bottom perspective view of a portable computing device suitable for use with the described embodiments; 
           [0017]      FIG. 4C  shows an illustrative view by which various bends in the flex can facilitate assembly of the portable computing device; and 
           [0018]      FIG. 5  shows a flow chart illustrating a method for assembling a portable computing device with a flexible circuit assembly. 
       
    
    
       [0019]    Those skilled in the art will appreciate and understand that, according to common practice, various features of the drawings discussed below are not necessarily drawn to scale, and that dimensions of various features and elements of the drawings may be expanded or reduced to more clearly illustrate the embodiments of the present invention described herein. 
       DETAILED DESCRIPTION 
       [0020]    Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
         [0021]    In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments in accordance with the described embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the described embodiments, it is understood that these examples are not limiting such that other embodiments may be used, and changes may be made without departing from the spirit and scope of the described embodiments. 
         [0022]    A flexible circuit (“flex”) is an electronic circuit printed on a flexible polymer substrate that can be utilized to construct a flexible connector in applications where flexibility, space savings, or other production constraints prevent traditional connectors, such as wires from being utilized. In some embodiments, a flex can be utilized to construct a flexible circuit assembly that connects a first component to a second component. For example, the flexible circuit assembly can interconnect a first electrical component to a second electrical component. The components can then communicate with each other over signals transmitted by the flex. The signals can be transmitted by a number of electrically conductive pathways that can take the form of leads and traces embedded within the flex. The electrically conductive pathways can handle discrete routing of a number of signals between the first and second electrical components. It should be noted that the electrically conductive pathways can be distributed across a number of different layers that make up the flex. 
         [0023]    One limitation of a flexible circuit construction is that signals can degrade if the electrical pathways within the flex extend across too great a distance. For this reason, designers generally minimize a length of the flex to avoid signal degradation. Unfortunately, this limits a distance across which the flex can be used to form an electrical connection. One solution to this problem is to boost the signal carried by the flex back up to a usable level. The signal can be boosted by signal boosting components surface mounted to the flex. In this way, the flex can extend across substantially greater distances. The signal boosters can be powered in any number of ways, including: embedding a discrete power specific layer within the flex; incorporating traces in the flex that carry power in addition to signals; and adding a power connector proximate the signal boosting components. In some embodiments, the power specific layer can take the form of a conductive substrate along the lines of a thin layer of conductive metal. In such an embodiment, the flex can also include one or more signal layers that each include a number of traces. The flexible circuit can also include a discrete grounding layer utilized to provide a convenient pathway to ground for components or circuits traveling through the flex. In some embodiments, the discrete grounding layer can isolate signal layers of the flexible circuit. 
         [0024]    In some embodiments, some portions of the flex may need to undergo substantially more bending than other portions of the flex. Flexibility of these portions of the flex can be increased by separating the power layer from one or more of the signal layers, when no interconnections between the separated power and signal layers are required in these portions. For example, in select regions of the flex a portion of a bonding layer that ordinarily joins the signal layer to the power layer can be removed so that the signal layer and the power layer can bend or flex independently. This decoupling of the layers reduces stress induced by bending of the flex. In some embodiments, the bending of the flex can make installation of the flex during an assembly operation substantially easier. In some specific embodiments, the bends can be configured to facilitate assembly of a top case to a bottom case of an electronic device, when the flex connects components distributed in both the top case and the bottom case. The flex can include a number of bends that facilitate the connection of a main logic board (MLB) to an input output (I/O) board. For example, the MLB can be located on a first housing component such as a top case and the I/O board can be located on a second housing component such as a bottom case. 
         [0025]    In some embodiments, a connector at one end of the flex can be secured to an electrical component by adding a stiffener along a surface of the flex opposite the connector. The stiffener can include arms extending laterally away from the connector that allow the stiffener to be securely fastened to attachment points on the electrical component. In embodiments, where the stiffener overlays a substantial portion of the connector, the stiffener can also normalize an amount of force exerted against the connector, thereby improving a reliability and fit of the connector with a connector receiver on the electrical component. The stiffeners can be attached near the connectors in any number of ways including by adhesive and by a soldering operation. In some embodiments, the stiffener can have three-dimensional geometry that allows portions of the stiffener to lie flat against corresponding attachment points of the electrical component to which it is secured. 
         [0026]    These and other embodiments are discussed below with reference to  FIGS. 1-5 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting. 
         [0027]      FIG. 1A  depicts flexible circuit assembly  100  in accordance with the various embodiments. Flexible circuit assembly  100  can include first connector assembly  102  at a first end of flexible circuit assembly  100  and a second connector assembly  104  at a second end of flexible circuit assembly  100 . Each of the connector assemblies can include a board-to-board connector for electrically coupling a first electrical component to a second electrical component. The first component can transmit a number of discrete transmissions to the second component across flexible circuit assembly  100  by way of a number of signal pathways or traces embedded within flexible substrate  106 . In one particular embodiment, the first component can be an input/output (“I/O”) board and the second component can be a main logic board (“MLB”) of a portable electronic device. It should be understood that the I/O board and MLB configuration described is used for exemplary purposes only and it should be understood that flexible circuit assembly  100  can be utilized to electrically couple any number of disparate electrical components. In some embodiments, flexible circuit assembly  100  can transmit data associated with many different types of user-accessible I/O ports, including for example Universal Serial Bus (USB) ports, High-definition Multimedia Interface (HDMI) ports, Digital Visual Interface (DVI) ports, Ethernet ports, DisplayPort ports, Thunderbolt ports, power ports and analog audio ports. Flexible substrate  106  can include numerous data and/or power specific layers across which data associated with the different ports can be distributed. In some embodiments, flexible substrate  106  can be bent and flexed so that flexible circuit assembly  100  avoids other circuitry within the portable electronic device. 
         [0028]    In some embodiments, the signal pathways embedded within flexible substrate  106  can have a length that causes the signal they carry to degrade across flexible circuit assembly  100  to an extent that the signals are too weak to be effectively utilized. In order to compensate for the signal degradation, flexible circuit assembly  100  can include booster assembly  108 , depicted in close up view  110 . Booster assembly  108  is positioned near first connector assembly  102  so that signals running through flexible substrate  106  can be boosted just prior to arriving at the component to which first connector assembly is connected. In this way, any additional signal degradation can be minimized due to the short span between first connector assembly  102  and booster assembly  108 . In some embodiments, booster assembly  108  can represent a number of surface mounted components (not depicted) for boosting the signal between the I/O board and the MLB. One of the surface mounted components can include a USB re-driver. Booster assembly  108  can also include shield  112  for covering and shielding one or more of the surface mounted components. Shield  112  can be an electromagnetic interference (EMI) shield made up of a number of radio frequency (RF) opaque layers. In some embodiments, at least one of the layers that form shield  112  can be surface mounted to flexible substrate  106  by way of grounding pads  114  and take the form of a fence configured to receive a shielding can that covers a top surface of components it is configured to shield. In some embodiments, the layers of shield  112  that are not surface mounted can be snapped to or soldered to the other layers of shield  112 . Snap attachment of the shielding can to the fence can make for easier access to components beneath the shielding can. In some embodiments, shield  112  can also be grounded through grounding pads  114  in order to form a faraday cage suitable for shielding the one or more surface mounted components from electromagnetic interference. Shield  112  can also be grounded by gasket  116 . In some embodiments, gasket  116  can be formed from a block of conductive foam. The conductive foam forming gasket  116  can form a robust grounding pathway between shield  112  and an interior surface of a housing of an associated portable electronic device when gasket  116  is compressed against the interior surface of the housing. In some embodiments the interior surface can be associated with a keyboard assembly. 
         [0029]      FIG. 1B  depicts a cross-sectional view of booster assembly  108  in accordance with section line A-A. Boosting component  152  is surface mounted to flexible substrate  106 . Boosting component  152  can include circuitry for boosting multiple signals carried by flexible circuit assembly  100 . In some embodiments, boosting component  152  can represent a number of separately adhered sub-assemblies in cases where different signals are boosted by separate sub-assemblies. In some embodiments, one or multiplexing components can be configured to cooperate with boosting component  152  so that a number of different types of signals can be separated and/or combined prior to or subsequent to boosting the power of the inputs. In some embodiments, boosting component  152  can be configured to overcome any signal degradation caused by the multiplexing components. Shield  112  can cover boosting component  152  and protect boosting component  152  from electromagnetic interference. In some embodiments, shield  112  cooperates with conductive material embedded in an exterior layer of flexible substrate  106  (see description of shield layer  164  below) to form a faraday cage that surrounds and protects boosting component  152  by preventing the passage of EMI through shield  112  with the faraday cage. Alternatively, a bottom side of the faraday cage can be formed by a grounding layer within flexible substrate  106  or by stiffener  118  when stiffener  118  is formed of electrically conductive material. In some embodiments, gasket  116  can form a grounding pathway for shield  112 . Gasket  116  can be adhesively secured to an internal surface of a device housing to help secure flexible circuit assembly  100  in place within the device housing. Gasket  116  can take the form of a conductive foam that increases in conductivity when compressed. The conductive foam can be a foam infused with metals along the lines of aluminum, copper, steel, or nickel. In some embodiments, shield  112  can also be grounded through grounding pads  114 . 
         [0030]      FIG. 1B  includes close up view  154 , which shows a magnified detail of flexible substrate  106 , which is made up of a number of discrete layers  156 ,  158 ,  160 ,  162  and  164 . In some embodiments, flexible substrate  106  includes a number of signal layers depicted as high-speed layer  156  and low-speed layer  160 . Each of the signal layers can include various trace patterns that distribute discrete signals through the respective layer. While high-speed layer  156  can be configured to provide passage for a majority of higher bandwidth signals and low-speed layer  160  can be configured for low bandwidth signals, in certain embodiments high-speed and low-speed signals can be interspersed between the signal layers As depicted, flexible substrate  106  also includes grounding layer  158  and power layer  162 ; however, different ordering of the various layers may be utilized in order to minimize interference effects such as induced capacitance, which can adversely affect the integrity of signals carried on high-speed layer  156  and low-speed layer  160 . In some embodiments, grounding layer  158  can help to insulate high-speed layer  156  from other signals and power traveling through flexible substrate  106 . Flexible substrate  106  can also include shield layers  164  that define an exterior surface of flexible substrate  106  and help to protect signals routed through flexible substrate  106  from external interference. Shield layers  164  can be formed of any suitable grounding or electromagnetic interference shielding film such as PC3300 film produced by Tatsuta Electronic Materials. Shield layers  164  can include electrically conductive materials that allow shield layers  164  to form a grounding pathway for components mounted to an exterior surface of flexible substrate  106  without having to include routing that carries the grounding pathway through high-speed layer  156  and into grounding layer  158 . In some embodiments, flexible circuit assembly  100  can also include stiffener  118 . Stiffener  118  can provide stiffness to a region of flexible substrate  106  beneath shield  112 . Stiffener  118  can attach to flexible circuit assembly  100  via an adhesive layer. Alternatively, stiffener  118  can be surface mounted to flexible substrate  106 . In some embodiments, stiffener  118  can be formed from sheet metal containing aluminum, copper, steel, or stainless steel. Stiffener  118  can be electrically coupled with shield  112  by way of electrically conductive pathways within flexible substrate  106  and grounding pads  114 . Stiffener  118  can also be formed from a non-conductive material. In such a case stiffener  118  can still provide mechanical support for shield  112 . 
         [0031]    In some embodiments, boosting component  152  can be electrically coupled with traces located in high-speed layer  156 . The close proximity of high-speed layer  156  to boosting component  152  depicted in  FIG. 1B  can simplify signal routing between high-speed layer  156  and boosting component  152 . Boosting component  152  can include one or more USB re-drivers that boost signals received from one or more multiplexers. The one or more USB re-drivers and one or more multiplexers can cooperate with other suitable components to boost and combine a number of high-speed signals from high-speed layer  156 . For example, the multiplexing circuitry can combines multiple signals along the lines of USB 3.0, USB 2.0, and DisplayPort signals into a single high-speed signal that can be boosted or amplified by the USB re-drivers. In some embodiments, high-speed signals from high-speed layer  156  can be combined with low-speed signals from low-speed layer  160  by the multiplexer. In some embodiments, separating out the USB  2 . 0  signal from the high-speed signal and multiplexing the USB signal with the low-speed signal may reduce interference. The low-speed signal can be carried on traces located on low-speed layer  160 . Grounding layer  158  can interconnect with various components that can benefit from a grounding connection. For example, grounding pad  114  can electrically couple with grounding layer  158  in order to ground shield  112 . Grounding layer  158  can also be useful for reducing interference between high-speed layer  156  and low-speed layer  160 . In some embodiments, boosting component  152  can electrically contact grounding layer  158 . In some embodiments boosting components  152  can require power. Flexible substrate  106  can include electrically conductive pathways that electrically couple boosting component  152  with power layer  162  so that boosting component  152  can draw power from power layer  162 . In some embodiments, grounding layer  158  and power layer  162  can take the form of a single conductive material. In some embodiments, power layer  162  can be configured to receive all power used to power an associated electronic device when the associated electronic device is receiving external power. 
         [0032]      FIG. 2A  shows how flexible circuit assembly  100  can also include a number of bend regions  202 ,  204 ,  206  and  208 . Some bend regions such as bend regions  202  and  204  can be configured to allow flexible circuit assembly  100  to avoid circuitry proximate a path across which flexible circuit assembly  100  extends. Other bend regions such as bend regions  206  and  208  can allow flexible circuit assembly  100  to accommodate motion proximate first connector assembly  102 . Because bend regions  206  and  208  undergo substantially more bending than regions  202  and  204 , the flexibility of bend regions  206  and  208  can be adjusted to accommodate the greater bending. It should be noted that while bend regions  206  and  208  are the only regions dedicated to this motion accommodation it should be noted that any number of bends can be utilized to accomplish this purpose depending on relative positioning between components and the nature of an assembly operation associated with the associated portable electronic device. In some embodiments, additional bends can be located proximate second connector assembly  104  for further accommodation of movement during an assembly operation.  FIG. 2A  also includes a close up view clearly depicting connector  210 . Connector  210  can be embodied as a board-to-board connector, as depicted. Connector  210  can be surrounded by a number of metallic strips  212  that are electrically coupled to shield layer  164  (not depicted, see  FIG. 1B ) of flexible substrate  106  provide a floor grounding function for connector  210 . By bonding metallic strips  212  directly to shield layer  164  of flexible substrate  106  conductive material within shield layer  164  can provide a grounding path for connector  210 . In some embodiments, metallic strip  212 - 1  can be formed of different material than the material used to form metallic strips  212 - 2  and  212 - 3 . For example, in some embodiments metallic strips  212 - 2  and  212 - 3  can be formed primarily of a copper alloy and metallic strip  212 - 1  can be formed at least in part of gold. In some embodiments, a windowed gasket formed of conductive foam can surround connector  210  and be compressed between metallic strips  212  and the component to which connector  210  is electrically coupled. The windowed gasket can insulate connector  210  against interference. 
         [0033]      FIG. 2B  depicts a detailed view of first connector assembly  102  of flexible circuit assembly  100 . In some embodiments, flexible circuit assembly  100  can include stiffener  214  for providing stiffness on one or both sides of flexible circuit assembly  100 . Stiffener  214  is depicted on the opposite side of second connector assembly  104 . Stiffener  214  can be surface mounted to flexible circuit assembly  100  or attached via adhesive. First connector assembly  102  can also include first bend region  202  and second bend region  204 . In some embodiments, bend regions  202  and  204  can allow flexible circuit assembly  100  to avoid underlying circuitry of the portable electronic device. For example such as components located on the MLB that could interfere with the function of flexible circuit assembly  100  can be avoided. In some embodiments, bend region  206  and bend region  208  may require a greater amount of flexibility than flexible circuit assembly  100  would generally allow. However, the flexibility of flexible circuit assembly  100  may be increased by splitting layers of flexible circuit assembly  100  in a particular region as detailed below. The hashed region shown in the closeup view of  FIG. 2B  shows an area across which the layers can be split or separated. 
         [0034]      FIG. 2C  depicts a cross-sectional view of flexible substrate  106  at a location in which flexible substrate  106  splits into multiple layers to form an air gap  216  between the layers.  FIG. 2C  shows how flexible substrate  106  is bonded together by at least one bonding layer formed of bonding sheet  218  adhered with two layers of coverlay  220 . By ending the bonding layer as depicted, air gap  216  is created between grounding layer  158  and low-speed layer  160 . In some embodiments, the separated layers can have different areas that can also allowing flexible circuit assembly  100  to bend. 
         [0035]      FIG. 3  shows how flexible circuit assembly  100  can also include stiffener  302 . Stiffener  302  can provide stiffness on one or both ends of flexible circuit assembly  100 . Stiffener  302  is depicted as being disposed at a single end of flexible circuit assembly  100  and includes arms  304 . Arms  304  can be coupled with the first or the second component in order to 
         [0036]      FIG. 5  shows a flow chart depicting a method  500  for assembling a portable computing device containing a flexible circuit assembly. At step  502  a first end of the flexible circuit assembly is coupled with a first electrical component, which is disposed within a first housing component. The coupling can be accomplished by a board-to-board connector or in some embodiments the flexible circuit assembly can be soldered to the first component. At step  504 , a second end of the flexible circuit assembly is coupled with a second component, which is disposed within a second housing component. At step  506 , the second housing component is shifted with respect to the first housing component, the relative movement between the components being accommodated by excess flexible circuit material contained within the flexible circuit assembly. At step  508  the first and second housing components are secured together. 
         [0037]    The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
         [0038]    The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. securely attach one end of flexible circuit assembly  100 . Arms  304  can define openings  306  for accepting fasteners that engage attachment points on one of the first and second component. Stiffener  302  can be attached to flexible substrate  106  via an adhesive layer or stiffener  302  can be surface mounted to flexible substrate  106 . In some embodiments, stiffener  302  can be formed from sheet metal containing aluminum, copper, steel, or stainless steel. In some embodiments, the stiffeners can help to ensure that grounding ring  308  that surrounds connector  310  receives an even amount of pressure for reliably grounding connector  310 . Stiffener  302  can also prevent connector  310 , which can take the form of a board-to-board connector from dislodging from a slot defined by an electrical component to which flexible circuit assembly  100  is attached. 
         [0039]      FIG. 4A  depicts a perspective view of portable computing device  400  suitable for use with the described embodiments. Portable computing device  400  can include top case  402  and bottom case  404 , which cooperate to form an internal volume. In some embodiments, top case  402  and bottom case  404  can be attached to each other. Attachment of top case  402  to bottom case  404  can be accomplished by any number of attachment features including by threaded fasteners, adhesive, snap attachments, or some combination of attachment the aforementioned attachment features. Circuitry for supporting I/O port functionality can be disposed within the internal volume. In some embodiments, portable computing device  400  can be a laptop that includes hinged display assembly  406 .  FIG. 4B  depicts another perspective view of portable computing device  400  and shows how top case  402  can include user accessible ports  408  for transferring data and/or power into and out of portable computing device  400 . In some embodiments, user accessible ports  408  can include any number of the following types of ports: power, USB 2.0, USB 3.0, audio, DisplayPort, High Definition Media Input, and camera media cards. 
         [0040]      FIG. 4C  shows how flexible circuit assembly  100  can be utilized to electrically couple two electrical components within portable computing device  400 : main logic board  410  and I/O board  412 . As depicted, bend region  206  of flexible circuit assembly  100  allows for translation of bottom case  404  with respect to top case  402  along axis  414  and bend region  208  of flexible circuit assembly  100  allows for rotation of bottom case  404  with respect to top case  402  about axis of rotation  416 .