Patent Publication Number: US-2023156900-A1

Title: Processor Heat Dissipation in a Stacked PCB Configuration

Description:
BACKGROUND 
     A computing device implements a processor, which executes instructions and generates heat in the process. Excess heat, however, can interfere with the operation of the computing device. For this reason, the computing device needs to be cooled. In basic architectures, a computing device implements a printed circuit board (PCB) that is attached to the processor. To cool this basic architecture, a heat sink located on the external surface or periphery of the computing device is used to transfer heat away from the printed circuit board. New and smaller circuit architectures reduce the footprint in electronic devices, and may include an integrated stacked PCB, in which the printed circuit boards are arranged in a stacked configuration, and the processor may be attached to a side of one of the printed circuit boards. Although a stacked PCB architecture facilitates reducing the overall size of a device, such as when implemented in a mobile device, cooling the processor and other components becomes a difficult challenge, and heat can be trapped inside the stacked PCB architecture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the techniques for processor heat dissipation in a stacked printed circuit board (PCB) configuration are described with reference to the following Figures. The same numbers may be used throughout to reference like features and components shown in the Figures: 
         FIG.  1    illustrates an example that supports processor heat dissipation in a stacked PCB configuration in accordance with one or more implementations as described herein. 
         FIG.  2    further illustrates an example that supports processor heat dissipation in a stacked PCB configuration in accordance with one or more implementations as described herein. 
         FIG.  3    further illustrates the examples that support processor heat dissipation in a stacked PCB configuration, such as in a computing device in accordance with one or more implementations as described herein. 
         FIG.  4    illustrates another example that supports processor heat dissipation in a stacked PCB configuration in accordance with one or more implementations as described herein. 
         FIG.  5    illustrates another example that supports processor heat dissipation in a stacked PCB configuration in accordance with one or more implementations as described herein. 
         FIG.  6    illustrates another example that supports processor heat dissipation in a stacked PCB configuration in accordance with one or more implementations as described herein. 
         FIG.  7    illustrates example method(s) for processor heat dissipation in a stacked PCB configuration in accordance with one or more implementations of the techniques described herein. 
         FIG.  8    illustrates various components of an example device that can be used to implement the techniques of processor heat dissipation in a stacked PCB configuration as described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Implementations of processor heat dissipation in a stacked printed circuit board (PCB) configuration are described, and provide techniques that can be implemented in any type of computing device, such as a wireless device, a smart device, mobile device (e.g., cellular phones, tablet devices, smartphones), consumer electronics, and the like. The techniques are implemented for cooling the processor and other components in a computing device by transferring heat away from the processor to a heat sink. Generally, smaller, mobile device architectures are implemented with a processor that generates the heat, which needs to be dissipated, yet the smaller device configurations are designed with internal components that are installed close together, making dissipation of the generated heat a challenge. Notably, the processor may also have a design specification requiring heat dissipation from both the top and the bottom of the component, yet a stacked printed circuit board (PCB) configuration precludes efficient heat dissipation, particularly on the stacked PCB side of the processor. 
     In aspects of the described processor heat dissipation in a stacked PCB configuration, a computing device, such as a mobile phone, wireless device, smartphone, or other communication device includes a processor for application processing that produces heat. To efficiently transfer the heat produced by the processor away from the computing device, a heat spreader may be used to transfer heat from the processor to a heat sink. Integrating the heat spreader in the stacked PCB configuration provides an additional path for heat transfer, in addition to cooling through a surface of a printed circuit board to a heat sink. 
     Unlike some conventional systems, this disclosure provides for heat dissipation in a device using one heat sink (in one example implementation), which facilitates device assembly. This also alleviates the difficulty of having to attach additional components to the processor while allowing for effective cooling on both sides of the processor. The top of the processor may be cooled conventionally, such as by using a thermally conductive material to create a connection to the heat sink. The bottom of the processor attaches to the main printed circuit board, and heat is transferred through a heat spreader via the main printed circuit board. Integrating a heat spreader with the stacked PCB configuration also eliminates the need to punch holes through the stacked printed circuit boards. This eliminates the restrictions on component design that would otherwise be required to work around the holes in the printed circuit boards. 
     In aspects of the described disclosure, a computing device has a processor that generates heat, and a stacked PCB configuration, which includes a main printed circuit board and an additional stacked printed circuit board. In implementations, the stacked PCB configuration may include more than two stacked printed circuit boards. The main printed circuit board and the stacked printed circuit board(s) are spaced apart, forming an enclosed cavity between the main printed circuit board and the stacked printed circuit board, with an enclosure material that encompasses or surrounds the enclosed cavity. 
     In an implementation, a processor is affixed to a side of the main printed circuit board that is opposite and facing away from the stacked printed circuit board in the stacked PCB configuration (e.g., the bottom of the processor attaches to the main printed circuit board). The processor generates heat, which is then transferred from the processor to the attached main printed circuit board and through the attached main printed circuit board into the enclosed cavity. To transfer this heat that is generated by the processor away from the processor and the stacked PCB configuration, a heat spreader is affixed to the main printed circuit board inside of the enclosed cavity. Generally, the heat spreader is an object or material that has a high thermal conductivity and is used as a conductive span between a heat source (e.g., the processor) and a heat exchanger (e.g., a heat sink). In aspects of the disclosure, the heat spreader may be implemented as a solid material, or as any type of a two-phase system, such as a heat-pipe, thermosyphon, vapor-chamber, and the like. The generated heat transfers from the heated end of the heat spreader to the cooler end of the heat spreader. 
     The heat spreader is connected to the main printed circuit board at a first end with a conductive material that facilitates heat transfer from the main printed circuit board to the heat spreader. A second end of the heat spreader is connected to the heat sink, which can be implemented as a passive heat exchanger that transfers the heat to a cooling medium, such as into the air, a liquid coolant, or another form of cooling medium. The heat spreader exits the enclosed cavity of the stacked PCB configuration via a cavity opening in the enclosed cavity between the main printed circuit board and the stacked printed circuit board. 
     The heat sink is located external to the stacked PCB configuration and dissipates the heat that is generated by the processor and transferred away from the processor and the stacked printed circuit boards by the heat spreader, allowing for temperature regulation in a device. In an implementation, the heat spreader may be attached to the main printed circuit board at multiple contact points, which allows for increased heat transfer from the processor and the stacked PCB configuration by increasing the number of contact points between the heat spreader and the main printed circuit board. In implementations, the heat sink may be integrated as the internal chassis of a computing device, such as a mobile wireless device, may be implemented as a heat sink separate from the internal chassis of the device, and/or as a combination thereof. In implementations, the internal chassis of a device, the heat sink, and/or the combination thereof can be linked or attached to the external housing of the device to facilitate the heat dissipation into ambient air that is external to the device. 
     While features and concepts of processor heat dissipation in a stacked PCB configuration can be implemented in any number of different devices, systems, environments, and/or configurations, implementations of processor heat dissipation in a stacked PCB configuration are described in the context of the following example devices, systems, and methods. 
       FIG.  1    illustrates an example  100  of a stacked printed circuit board (PCB) configuration  102  in which techniques for processor heat dissipation in a stacked PCB configuration can be implemented, as described herein. In this example  100 , the stacked PCB configuration  102  includes a main printed circuit board  104  and an additional stacked printed circuit board  106 . In alternate implementations, the stacked PCB configuration  102  may include more than two stacked printed circuit boards. As shown in this example  100 , the main printed circuit board  104  and the stacked printed circuit board  106  in the stacked PCB configuration  102  are spaced apart in a manner that forms an enclosed cavity  108  between the main printed circuit board  104  and the stacked printed circuit board  106  with an enclosure material  110  that encompasses or surrounds the enclosed cavity  108 . In an implementation, the enclosure material  110  can be formed with any type of material utilized to encompass or surround the enclosed cavity  108 , such as to create the enclosed cavity  108  as a void space. 
     In a configuration, the main printed circuit board  104  and the stacked printed circuit board  106  of the stacked PCB configuration  102  can be held spaced apart by an interposer PCB  112  or interconnect board, which is partially shown. In this configuration, the interposer PCB  112  (interconnect board) is attached to the periphery of both the main printed circuit board  104  and the stacked printed circuit board  106 , holding the stacked PCB configuration  102  in place and forming the enclosed cavity  108  between the two stacked PCBs. Another example is further shown and described with reference to  FIG.  2   . In implementations, the enclosed cavity  108  may be maintained as an empty void space between the stacked PCBs. Alternatively, the enclosed cavity  108  may be filled with a thermal paste, a thermal gel, or other type of a solid material to reduce the air gap between the stacked PCBs inside the stacked PCB configuration. 
     Generally, the stacked PCB configuration  102  may be implemented in a mobile wireless device or other type of computing device to address the space constraints for component configurations, particularly in smaller devices, as well as to decrease interference and noise that may be generated in a wireless communication device. A printed circuit board in the stacked configuration is typically a laminated, layered structure of conductive and insulating layers. Each printed circuit board may contain components in designated locations on the outer layers of the printed circuit board, and generally, each printed circuit board can include electrical connections between various component terminals for connection of the device components. A printed circuit board may also have various conductive layers designed with a pattern of conductors that provide electrical connections on a particular conductive layer. Alternatively or in addition, printed circuit boards may contain vias, which are small holes through the laminate and plated with copper. The vias are then the electrical interconnection between layers that are otherwise insulated in the laminate structure, and provide for connectability between conductive layers of a printed circuit board. 
     In this example  100 , a processor  114  is affixed to a side of the main printed circuit board  104  that is opposite and facing away from the stacked printed circuit board  106  (e.g., the bottom of the processor attaches to the main printed circuit board). The processor  114  may take the form of a microprocessor, a central processing unit, a graphics processing unit, a controller, or any another type of processing device, such as in a mobile wireless device or other type of computing device. The processor  114  executes instructions (e.g., computer-readable instructions) and produces heat in the process, which is transferred from the processor  114  to the attached main printed circuit board  104  and through the attached main printed circuit board into the enclosed cavity  108 . 
     Generally, smaller, mobile device architectures are implemented with a processor  114  that generates heat, which needs to be dissipated, yet the smaller device configurations are designed with internal components that are installed close together, making dissipation of the generated heat a challenge. Notably, the processor  114  may have a design specification requiring heat dissipation from both the top and the bottom of the component, yet the stacked PCB configuration  102  precludes efficient heat dissipation, particularly on the stacked PCB side of the processor, where the bottom of the processor attaches to the main printed circuit board  104 . 
     To transfer this heat that is generated by the processor  114  away from the processor and the stacked PCB configuration  102 , a heat spreader  116  is affixed to the main printed circuit board  104  inside of the enclosed cavity  108 . Generally, a heat spreader is an object or material that has a high thermal conductivity and is used as a conductive span between a heat source (e.g., the processor  114 ) and a heat exchanger, such as a heat sink  118  in this example configuration. In implementations, the heat spreader  116  may take the form of a solid material, a hollow tube, or other type of chamber that contains fluid. When one side of the heat spreader  116  is exposed to a heat source, the fluid inside the heated end of the heat spreader transitions to vapor, which migrates to the other end of the heat spreader, where it condenses back to fluid. This is effective to transfer heat from the heated end of the heat spreader  116  to the cooler end of the heat spreader. This process of heat dissipation can be implemented with any number and/or type of heat spreaders, including, but not limited to, a two-phase spreader system, a vapor chamber, a heat pipe, a thermosyphon, and the like. 
     A first end of the heat spreader  116  is connected to the main printed circuit board  104 , such as affixed with a conductive material  120  that facilitates to interface the heat spreader  116  with the main printed circuit board  104 . In implementations, the conductive material  120  may be a thermal paste or thermal gel, or alternatively, a copper slug or copper tape, such as may be affixed to the main printed circuit board  104  and/or to the heat spreader  116  by soldered connections. Additionally, the conductive material  120  may be used to account for tolerances and height differences of components on the main printed circuit board  104  in order to avoid interference by the heat spreader  116  with the functionality of other device components, while effectively transferring heat away from the main printed circuit board. A second end of the heat spreader  116  is connected to the heat sink  118  for thermal transfer. The heat sink  118  can be implemented as a passive heat exchanger that transfers heat to a cooling medium, which may be into the air, a liquid coolant, or another form of cooling medium. 
     In this example  100 , the heat spreader  116  exits the enclosed cavity  108  via a cavity opening  122  in the enclosed cavity  108  between the main printed circuit board and the stacked printed circuit board  106  in the stacked PCB configuration  102 . In an implementation, this cavity opening  122  may be an opening in the interposer PCB (not shown). The heat sink  118  is located external to the stacked PCB configuration  102 , and dissipates the heat that is generated by the processor  114  and transferred away from the processor and the stacked PCBs by the heat spreader  116 , allowing for temperature regulation in a device. In implementations, the heat sink  118  can be formed as a metal plate or thin sheet of metal, such as aluminum. Additionally, the heat sink  118  may include fins to increase the exposed surface area for cooling purposes, and/or may also incorporate fans or a liquid cooling process to dissipate the heat. In alternate configurations, a shield structure (not shown) may be used to separate the processor  114  from the heat sink  118  inside of a device. Accordingly, some heat transfer may occur through the shield structure to the heat sink, which facilitates to further cool the device in addition to the heat transfer that occurs from the stacked PCB configuration  102  to the heat sink  118  via the heat spreader  116 . 
       FIG.  2    further illustrates an example  200  of features for processor heat dissipation in a stacked PCB configuration, such as described with reference to  FIG.  1   . In addition to the heat spreader  116  connecting the main printed circuit board  104  to the heat sink  118  via the conductive material  120 , additional thermally conductive material  202  may be used to connect the processor  114  directly to the heat sink  118 . The additional conductive material  202  facilitates the processor chip dissipating heat through its case (e.g., the top of the processor) directly to the heat sink, which is also further shown and described with reference to  FIG.  5   . In implementations, the conductive material  202  may be similar or the same as the conductive material  120 . For example, the conductive material  202  is a thermal interface material that may be a copper block (or copper slug) and thermal paste, or copper tape and thermal paste, or just thermal paste. Any combination of heat spreader(s), a heat sink, and conductive material configurations may be utilized to transfer and/or dissipate the heat generated in a device. 
     This example  200  also further illustrates the interposer PCB  112  (interconnect board) which includes PCB interconnects  204  between the main printed circuit board  104  and the stacked printed circuit board  106  to electrically interconnect the printed circuit boards. As further shown and described with reference to  FIG.  3   , the heat spreader may also be attached to other device components  206  with a thermal interface material  208  (e.g., a copper slug and thermal paste, or just thermal paste) to dissipate heat from the stacked PCB configuration  102 . 
       FIG.  3    further illustrates an example  300  of features for processor heat dissipation in a stacked PCB configuration, as described with reference to  FIGS.  1  and  2   , implemented in a computing device  302  as shown. As shown in this example  300 , the computing device  302  may be any type of a mobile phone, wireless device, smartphone, computing device, tablet device, electronic, and/or communication device implemented with various components, such as an application processor and memory, as well as any number and combination of different components as further described with reference to the example device shown in  FIG.  8   . In this example  300 , the computing device  302  incorporates a processor  114  in a stacked PCB configuration  102 , and the processor generates heat that needs to be dissipated, as described with reference to  FIGS.  1  and  2   . 
     Generally, the computing device  302  also incorporates an example of the heat sink  118  inside the computing device. Alternatively or in addition, the heat sink  118   may be located external to the computing device  302  (not shown), such as positioned on the periphery of the device, exposing the heat sink to air around the device to increase and facilitate heat dissipation. The heat sink  118  can be implemented as a passive heat exchanger that transfers heat to a cooling medium, which may be into the air external to the device  302 , a liquid coolant, or another form of cooling medium. 
     In implementations, the heat sink  118  can be formed as a metal plate or thin sheet of metal, such as aluminum, and can vary in size, depending on the quantity of heat to be transferred away from the processor  114  and dissipated in the device. For example, the heat sink  118  may have length and width dimensions approximately as large as the footprint of the computing device  302  to effectively dissipate the generated heat. In implementations, heat sink  118  may also have dimensions smaller or greater than the overall size of the computing device  302 . Notably, the heat sink  118  can be implemented as the internal chassis of the device  302 , may be implemented as a heat sink separate from the internal chassis of the device, and/or a combination thereof. In implementations, the internal chassis of the device, the heat sink, and/or the combination thereof is linked or attached to the external housing of the computing device  302  to facilitate the heat dissipation into ambient air that is external to the device. 
       FIG.  4    illustrates another example  400  of techniques for processor heat dissipation in a stacked PCB configuration, as described with reference to  FIGS.  1 - 3   , and implemented in the computing device  302 . In this example  400 , the heat spreader  116  may be affixed to the main printed circuit board  104  at any number of multiple contact points  402 . The heat spreader  116  may have an additional end  404  that allows the heat spreader  116  to connect to the multiple contact points  402  on the main printed circuit board  104 . These multiple contact points  402  on the main printed circuit board  104  are in addition to the connection point between the first end of the heat spreader  116  and the main printed circuit board  104 , such as shown and described with reference to  FIG.  1   . In this implementation, the second end of the heat spreader  116  is connected to the heat sink  118 , as illustrated in  FIG.  1   . The multiple contact points  402  of the heat spreader  116  on the main printed circuit board  104  allow for increased heat transfer from the processor  114  and the stacked PCB configuration  102  by increasing the number of connection points via which the heat can transfer between the main printed circuit board  104  and the heat spreader  116 . 
     In implementations, the heat spreader  116  may be affixed to specific contact points of high heat on the main printed circuit board  104 . Alternatively or in addition, the heat spreader  116  may be affixed to multiple solid components on the main printed circuit board  104 . In implementations, the heat spreader  116  is affixed to the main printed circuit board  104  at multiple contact points  402  with a conductive material  120  that facilitates to interface the heat spreader  116  with the main printed circuit board  104 , such as described with reference to  FIG.  1   . This process of heat dissipation can be implemented with any number and/or type of heat spreaders, including, but not limited to, a two-phase spreader system, a vapor chamber, a heat pipe, a thermosyphon, and the like. 
       FIG.  5    further illustrates another example  500  of features for processor heat dissipation in a stacked PCB configuration, such as described with reference to  FIGS.  1 - 4   , and implemented in a computing device  302 . As shown in this example  500 , additional conductive material  502  may be used to connect the processor  114  directly to the heat sink  118 , thereby increasing the heat transfer from the processor to the heat sink, in addition to the heat spreader  116  connecting the main printed circuit board  104  to the heat sink  118  via the conductive material  120 . The additional conductive material  502  is used to facilitate the processor chip dissipating heat through its case directly to the heat sink. In implementations, the conductive material  502  may be similar or the same as the conductive material  120 . It should be noted that this configuration shown and described with reference to  FIG.  5    may be combined with an additional heat spreader such as further shown and described with reference to  FIG.  6   . Any combination of heat spreader(s), a heat sink, and conductive material configurations may be utilized to transfer and/or dissipate the heat generated in a device. 
       FIG.  6    further illustrates another example  600  of features for processor heat dissipation in a stacked PCB configuration, such as described with reference to  FIGS.  1 - 4   , and implemented in a computing device  302 . As shown in this example  600 , an additional heat spreader  602  may be used to connect the processor  114  to the heat sink  118  to increase the heat transfer from the processor to the heat sink, in addition to the heat spreader  116  connecting the main printed circuit board  104  to the heat sink  118 . Alternatively or in addition, the additional heat spreader  602  may connect the main printed circuit board  104   to the heat sink  118  to increase the connections for heat transfer from the processor  114  to the heat sink  118  via the main printed circuit board. 
     In implementations, the additional heat spreader  602  may also be integrated with the heat spreader  116 . For example, a first end of the additional heat spreader  602  may be connected to the processor  114  via the main printed circuit board  104  using a conductive material  120 , and the second end of the additional heat spreader  602  may be connected to the heat spreader  116 . In other implementations, the additional heat spreader  602  may alternatively connect to an additional heat sink that is implemented in addition to the heat sink  118 . Further, any combination of these heat spreader and heat sink configurations may be utilized to transfer and/or dissipate the heat generated in a device. 
       FIG.  7    illustrates example method(s)  700  for processor heat dissipation in a stacked PCB configuration, as described herein, and is generally described with reference to a computing device implemented with a processor that generates heat in the device. The order in which the method is described is not intended to be construed as a limitation, and any number or combination of the described method operations can be performed in any order to perform a method, or an alternate method. 
     At  702 , heat is generated by a processor that executes instructions. For example, the processor  114  executes instructions (e.g., computer-readable instructions) and produces heat in the process, which is transferred from the processor  114  to the attached main printed circuit board  104  and through the attached main printed circuit board into the enclosed cavity  108 . 
     At  704 , the heat is transferred along a heat spreader that has a first end connected to the processor via a main printed circuit board (PCB) in a stacked PCB configuration and a second end connected to a heat sink located external to the stacked PCB configuration. For example, the heat spreader  116  is affixed to the main printed circuit board  104  inside of the enclosed cavity  108 , and the heat is transferred along the heat spreader  116  that has a first end connected to the processor  114  via the main printed circuit board  104  in the stacked PCB configuration  102 , and a second end of the heat spreader is connected to the heat sink  118  located external to the stacked PCB configuration. The heat is transferred along the heat spreader  116  through the opening  122  in the enclosed cavity  108  that is formed between the main printed circuit board  104  and the additional, stacked printed circuit board  106  in the stacked PCB configuration  102 . 
     The heat may be further transferred away from the processor  114  along at least one additional heat spreader. For example, the additional heat spreader  602  may be utilized to connect the processor  114  to the heat sink  118  to increase heat transfer from the processor  114  to the heat sink  118 , in addition to the heat spreader  116  connecting the main printed circuit board  104  to the heat sink  118 . In other implementations, the heat spreader  116  may be affixed to the main printed circuit board  104  at multiple contact points, which provide for additional heat transfer from the processor  114  and the stacked PCB configuration  102  by increasing the number of connection points between the heat spreader  116  and the main printed circuit board. 
     At  706 , the transferred heat is dissipated by the heat sink located external to the stacked PCB configuration. For example, the heat sink  118  is located external to the stacked PCB configuration  102 , and dissipates the heat that is generated by the processor  114  and transferred away from the processor  114  and the stacked printed circuit boards by the heat spreader  116 , allowing for temperature regulation in a device. 
     At  708 , the heat generated by the processor is further dissipated through a side of the processor that thermally contacts the heat sink via a thermal interface material. For example, a first side of the processor  114  (e.g., the bottom of the processor) is affixed to the main printed circuit board  104  and a second side of the processor  114  (e.g., the top of the processor) thermally contacts the heat sink  118  via a thermal interface material to further dissipate the heat generated by the processor. In implementations, the thermal interface material may be a copper block (or copper slug) and thermal paste, or copper tape and thermal paste, or just thermal paste. 
       FIG.  8    illustrates various components of an example device  800 , which can implement aspects of the techniques and features for processor heat dissipation in a stacked PCB configuration, as described herein. The example device  800  can be implemented as any of the devices described with reference to the previous  FIGS.  1 - 7   , such as any type of a wireless device, mobile device, mobile phone, flip phone, client device, companion device, paired device, display device, tablet, computing, communication, entertainment, gaming, media playback, and/or any other type of computing and/or electronic device. For example, the computing device  302  described with reference to  FIG.  3    may be implemented as the example device  800 . 
     The example device  800  can include various, different communication devices  802  that enable wired and/or wireless communication of device data  804  with other devices. The device data  804  can include any device data and content that is generated, processed, determined, received, stored, and/or transferred from one computing device to another, and/or synched between multiple computing devices. Generally, the device data  804  can include any form of audio, video, image, graphics, and/or electronic data that is generated by applications executing on a device. The communication devices  802  can also include transceivers for cellular phone communication and/or for any type of network data communication. 
     The example device  800  can also include various, different types of data input / output (I/O) interfaces  806 , such as data network interfaces that provide connection and/or communication links between the devices, data networks, and other devices. The I/O interfaces  806  can be used to couple the device to any type of components, peripherals, and/or accessory devices, such as a computer input device that may be integrated with the example device  800 . The I/O interfaces  806  may also include data input ports via which any type of data, information, media content, communications, messages, and/or inputs can be received, such as user inputs to the device, as well as any type of audio, video, image, graphics, and/or electronic data received from any content and/or data source. 
     The example device  800  includes a processor system  808  of one or more processors (e.g., any of microprocessors, controllers, and the like) and/or a processor and memory system implemented as a system-on-chip (SoC) that processes computer-executable instructions. The processor system may be implemented at least partially in computer hardware, which can include components of an integrated circuit or on-chip system, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), and other implementations in silicon and/or other hardware. Alternatively or in addition, the example device  800  can be implemented with any one or combination of software, hardware, firmware, or fixed logic circuitry that may be implemented in connection with processing and control circuits, which are generally identified at  810 . The example device  800  may also include any type of a system bus or other data and command transfer system that couples the various components within the device. A system bus can include any one or combination of different bus structures and architectures, as well as control and data lines. 
     The example device  800  also includes memory and/or memory devices  812  (e.g., computer-readable storage memory) that enable data storage, such as data storage devices implemented in hardware that can be accessed by a computing device, and that provide persistent storage of data and executable instructions (e.g., software applications, programs, functions, and the like). Examples of the memory devices  812  include volatile memory and non-volatile memory, fixed and removable media devices, and any suitable memory device or electronic data storage that maintains data for computing device access. The memory devices  812  can include various implementations of random-access memory (RAM), read-only memory (ROM), flash memory, and other types of storage media in various memory device configurations. The example device  800  may also include a mass storage media device. 
     The memory devices  812  (e.g., as computer-readable storage memory) provide data storage mechanisms, such as to store the device data  804 , other types of information and/or electronic data, and various device applications  814  (e.g., software applications and/or modules). For example, an operating system  816  can be maintained as software instructions with a memory device and executed by the processor system  808  as a software application. The device applications  814  may also include a device manager, such as any form of a control application, software application, signal-processing and control module, code that is specific to a particular device, a hardware abstraction layer for a particular device, and so on. 
     In this example, the device  800  also includes the processor system  808  implemented in a stacked PCB configuration  818 , such as described with reference to  FIGS.  1 - 7   . In the stacked PCB configuration  818 , a heat spreader  820  is integrated to connect the processor system  808  and/or the stacked PCB configuration  818  to a heat sink  822 . The heat spreader transfers generated heat away from the processor system  808 , and the heat sink  822  dissipates the heat in the device. 
     The example device  800  can also include integrated devices  824 , such as a microphone and/or camera devices, as well as motion sensors  826 , which may be implemented as components of an inertial measurement unit (IMU). The motion sensors  826  can be implemented with various sensors, such as a gyroscope, an accelerometer, and/or other types of motion sensors to sense motion of the device. The motion sensors  826  can generate sensor data vectors having three-dimensional parameters (e.g., rotational vectors in x, y, and z-axis coordinates) indicating location, position, acceleration, rotational speed, and/or orientation of the device. The example device  800  can also include one or more power sources  828 , such as when the device is implemented as a wireless device and/or mobile device. The power sources  828  may include a charging and/or power system, and can be implemented as a flexible strip battery, a rechargeable battery, a charged super-capacitor, and/or any other type of active or passive power source. 
     The example device  800  can also include an audio and/or video processing system  830  that generates audio data for an audio system  832  and/or generates display data for a display system  834 . The audio system and/or the display system may include any types of devices or modules that generate, process, display, and/or otherwise render audio, video, display, and/or image data. Display data and audio signals can be communicated to an audio component and/or to a display component via any type of audio and/or video connection or data link. In implementations, the audio system and/or the display system are integrated components of the example device  800 . Alternatively, the audio system and/or the display system are external, peripheral components to the example device. 
     Although implementations of processor heat dissipation in a stacked PCB configuration have been described in language specific to features and/or methods, the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as example implementations of processor heat dissipation in a stacked PCB configuration, and other equivalent features and methods are intended to be within the scope of the appended claims. Further, various different examples are described and it is to be appreciated that each described example can be implemented independently or in connection with one or more other described examples. Additional aspects of the techniques, features, and/or methods discussed herein relate to one or more of the following: 
     A computing device, comprising: a processor configured for executable instructions processing during which the processor generates heat; a main printed circuit board (PCB) in a stacked PCB configuration, the processor affixed to the main printed circuit board; and a heat spreader having a first end connected to the processor via the main printed circuit board by a conductive material, and a second end connected to a heat sink located external to the stacked PCB configuration, the heat spreader configured to transfer the heat away from the processor to the heat sink. 
     Alternatively or in addition to the above described computing device, any one or combination of: the stacked PCB configuration includes the main printed circuit board and at least one additional printed circuit board, and the stacked PCB configuration forms an enclosed cavity between the main printed circuit board and the at least one additional printed circuit board, through which heat dissipation is restricted. The heat spreader exits the enclosed cavity via an opening in the enclosed cavity between the stacked PCB configuration. The computing device further comprising at least one additional heat spreader connected to the heat sink and configured to further transfer the heat away from the processor to the heat sink. The at least one additional heat spreader is integrated with the heat spreader, the at least one additional heat spreader having a first end connected to the processor via the main printed circuit board, and a second end connected to the heat spreader. The conductive material is a copper slug that affixes the processor to the main printed circuit board, and the heat spreader is a heat pipe that transfers the heat away from the processor to the heat sink. A first side of the processor is affixed to the main printed circuit board and a second side of the processor contacts the heat sink via a thermal interface material. The heat spreader has at least one additional end connected to the processor via the main printed circuit board by the conductive material. The at least one additional end of the heat spreader connects to a different location on the main printed circuit board than the first end of the heat spreader. 
     A system, comprising: a processor configured for executable instructions processing during which the processor generates heat; a stacked printed circuit board (PCB) configuration, the processor affixed to a main printed circuit board of the stacked PCB configuration; a heat sink configured to dissipate heat away from the processor; and a heat spreader having a first end connected to the processor via the main printed circuit board by a conductive material, the heat spreader configured to transfer the heat away from the processor to a second end of the heat spreader, the second end connected to the heat sink located external to the stacked PCB configuration. 
     Alternatively or in addition to the above described system, any one or combination of: the stacked PCB configuration includes the main printed circuit board and at least one additional printed circuit board, and the stacked PCB configuration forms an enclosed cavity between the main printed circuit board and the at least one additional printed circuit board, through which heat dissipation is restricted. The heat spreader exits the enclosed cavity via an opening in the enclosed cavity between the stacked PCB configuration. A first side of the processor is affixed to the main printed circuit board and a second side of the processor contacts the heat sink via a thermal interface material. The system further comprising at least one additional heat spreader connected to the heat sink and configured to further transfer the heat away from the processor to the heat sink, the at least one additional heat spreader being integrated with the heat spreader, wherein the at least one additional heat spreader has a first end connected to the processor via the main printed circuit board, and has a second end connected to the heat spreader. The heat spreader is a heat pipe that transfers the heat away from the processor to the heat sink. The heat spreader has at least one additional end connected to the processor via the main printed circuit board by the conductive material. 
     A method, comprising: generating heat by a processor that executes instructions; transferring the heat along a heat spreader that has a first end connected to the processor via a main printed circuit board (PCB) in a stacked PCB configuration and a second end connected to a heat sink located external to the stacked PCB configuration; and dissipating the transferred heat by the heat sink located external to the stacked PCB configuration. 
     Alternatively or in addition to the above described method, any one or combination of: the heat is transferred along the heat spreader through an opening in an enclosed cavity formed between the main printed circuit board and at least one additional printed circuit board in the stacked PCB configuration. The heat is further transferred away from the processor along at least one additional heat spreader. At least one additional end of the heat spreader connects to a different location on the main printed circuit board than the first end of the heat spreader.