Patent Publication Number: US-2019196558-A1

Title: System with socketed processing device for high shock and vibration environments

Description:
BACKGROUND OF THE INVENTION 
     Central Processing Units (CPUs) may be configured as socketed devices, meaning that the CPUs are fitted into a socket soldered onto the motherboard (PCBs). These CPUs must make contact with thousands of tiny fingers for electrical connections, and may be held into these sockets via springs of one form or another.  FIG. 1  shows a typical prior art system  100  to secure a CPU in a CPU socket. The CPU is arranged between a bolster plate on one side of a PCB and a heatsink assembly on another side of the PCB. The heatsink is screwed down against a spring assembly, which tightly controls the compression force on the CPU and the pins in the socket. This compression force must be sufficient to keep the landing pads, for instance, copper contacts, on the CPU in constant contact with the pins in the socket in order to maintain electrical connections between the CPU and other components. For environments with high shocks and vibrations, such as may be expected in a vehicle, the heatsink may move and transmit all its inertial forces through the spring assembly and the bolster plate. The movements of the heatsink may reduce the compression force on the CPU, thereby causing fretting at the contact regions between the pins in the socket and the landing pads on the CPU, as well as intermittent connections. In addition, the movements of the heatsink may also cause the PCB to bend significantly, which may result in damage to the PCB. Therefore, in such environments, CPUs that come in solderable packages are typically used instead of socketed CPUs. 
     BRIEF SUMMARY OF THE INVENTION 
     The present disclosure provides for a system, comprising a circuit board, a socket attached to the circuit board, a processing device fitted in the socket, and a mounting plate attached to the circuit board wherein the processing device is arranged between the circuit board and the mounting plate such that the processing device is secured to the socket by a compression force applied by the mounting plate. 
     The system may further comprise a heatsink adaptor arranged between the processing device and the mounting plate, wherein the processing device is arranged between the circuit board and the heatsink adaptor such that the processing device is secured to the socket by a second compression force applied by the heatsink adaptor. 
     The mounting plate may further comprise a heatsink structure arranged at least partially within the mounting plate. The heatsink structure may be a cooling channel that circulates a fluid through an interior of the mounting plate. 
     The mounting plate and/or the heatsink adaptor may be attached to the circuit board through a first set of fasteners and at least one bolster plate. The mounting plate may additionally be attached to the circuit board through a plurality of standoffs. The first set of fasteners may be separated from the plurality of standoffs by a predetermined lateral distance which corresponds to the compression force applied by the mounting plate meeting a predetermined minimum compression force. 
     The compression force applied by the mounting plate and/or the heatsink adaptor may be controlled by at least one spring assembly. 
     The system may further comprise a vehicle. The processing device may be a processing unit of an autonomous driving computing system of the vehicle. 
     The disclosure further provides for attaching a socket to a circuit board, fitting a processing device in the socket, and attaching a mounting plate to the circuit board such that the processing device is arranged between the circuit board, and such that the mounting plate and the processing device is secured to the socket by a compression force applied by the mounting plate. The method may further comprise attaching a heatsink adaptor such that the processing device is arranged between the circuit board and the heatsink adaptor, and such that the processing device is secured to the socket by a second compression force applied by the heatsink adaptor; and attaching the heatsink adaptor to the mounting plate 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a typical prior art system. 
         FIG. 2  illustrates an example processing device system in accordance with aspects of the disclosure. 
         FIG. 3  illustrates an example processing device system in accordance with aspects of the disclosure. 
         FIG. 4  illustrates an example processing device system in accordance with aspects of the disclosure. 
         FIG. 5  is a functional diagram of an example vehicle in accordance with aspects of the disclosure. 
         FIG. 6  is an example flow diagram illustrating an example method in accordance with aspects of the disclosure. 
         FIG. 7  is another example flow diagram illustrating an example method in accordance with aspects of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Overview 
     The technology relates generally to securing a socketed processing device in high shock and vibration environments, such as may be expected inside a vehicle. In particular, in a system that requires high-precision computing devices, such as in an autonomous or semi-autonomous vehicle system, the processing unit must be reliably connected to thousands of pins to ensure proper and safe operation of the vehicle. Therefore, it is critical in such a system that all the connections to the processing unit are maintained in the event of any shocks and/or vibrations likely to be encountered by the vehicle, e.g., a truck. To ensure reliable connections in such environments, a processing device may be secured to a socket on a circuit board with a necessary compression force. 
     An example processing device system may include a heatsink adaptor used to secure a processing device to a socket attached to a circuit board. The heatsink adaptor may apply a compression force on the processing device below the heatsink adaptor in order to keep the processing device secured in the socket. Above the heatsink adaptor, a mounting plate may be attached to the circuit board through a plurality of standoffs. The mounting plate may also include a cooling channel or a heatsink structure. The processing device may be secured in the socket by the heatsink adaptor through at least one spring assembly, a first set of fasteners, and at least one bolster plate before the mounting plate is attached to the circuit board. The heatsink adaptor may be secured to the mounting plate by a second set of fasteners. The dimensions of the various elements may be designed to better accommodate manufacturing tolerances. 
     In another example processing device system, a mounting plate may be used directly to secure a processing device to a socket attached to a circuit board. Here, the mounting plate may directly apply a compression force on the processing device below the mounting plate to secure the processing device to the socket. By eliminating the heatsink adaptor and, as a result, a second set of fasteners, manufacturing cost of the processing device system may be reduced. Further, the distance that heat must travel from the processing device to the mounting plate may be reduced, allowing for a more efficient heat transfer. 
     The features described herein may maintain a compression force required to secure a processing device to a socket and prevent damage by preventing fretting and pitting all while preventing intermittent electrical connections with the processing device. In addition, such processing device systems may further allow for processing devices to be operated at higher wattages (performance) due to the decreased thermal resistance when a processing device is directly mounted to a mounting plate with a heatsink structure, such as a cooling channel (i.e., a cold plate). Because of all this, the processing device systems described herein may be ideal for use in high shock and vibration environments such as those that are likely in vehicles, including passenger vehicles (for instance, small cars, minivans), trucks (for instance, garbage trucks, oil trucks, tractor-trailers, etc.), and busses. In particular, in a system that requires high-precision computing devices, such as in an autonomous or semi-autonomous vehicle system, the processing unit must be reliably connected to thousands of pins to ensure proper and safe operation. The connections must also be capable of withstanding shocks and vibrations encountered by the vehicle. 
     Example Systems 
       FIG. 2  shows an example processing device system  200  according to aspects of the disclosure. A socket  210  is attached onto a circuit board  220 . A processing device  230  is fitted in the socket  210 . The heatsink adaptor  240  is secured to the circuit board  220  through a first set of fasteners  242  and at least one bolster plate  244 . The heatsink adaptor  240  may apply a compression force on the processing device  230  below the heatsink adaptor  240  in order to keep the processing device  230  secured in the socket  210 . The compression force may be controlled by at least one spring assembly  250  positioned between the heatsink adaptor  240  and the circuit board  220 . 
     Above the heatsink adaptor  240 , a mounting plate  260  is attached to the circuit board through a plurality of standoffs  262 . The heatsink adaptor  240  is secured to the mounting plate  260  by a second set of fasteners  264 . Since both the heatsink adaptor  240  and the circuit board  220  are attached to the mounting plate  260 , there may be very little movement between the heatsink adaptor  240  and the circuit board  220 , which means that the compression force on the processing device  230  is better maintained during shocks and vibrations. 
     The circuit board  220  may be any type of board that can provide mechanical and electrical supports to electronic components. For example, the circuit board  220  may be a printed circuit board (PCB), a flexible PCB, a multiple-layer PCB, a breadboard, a stripboard, a perfboard, etc., or any combination thereof. 
     The processing device  230  may be any type of device that can process data. For example, the processing device  230  may be a Central Processing Unit (CPU), a graphics processing unit (GPU), a Field-Programmable Gate Array (FPGA), a microprocessor, a logic circuit, etc., or any combination thereof. For instance, the processing device may have multiple microprocessors, such a multi-core chip, or may include various types of processors housed together on one or more chips. 
     In the example of  FIG. 2 , the mounting plate  260  also includes a cooling channel  266 . This cooling channel  266  may circulate fluid through an interior of the cooling channel, thereby removing excess heat from the processing device to prevent damage. The fluid may be a liquid or a gas. Alternatively, though not shown, the mounting plate  260  may have a heatsink structure on a top side of the mounting plate  260  such that the weight of the heatsink structure is supported by the mounting plate  260 . For example, the heatsink structure may be fins. As yet another example, the mounting plate  260  may simply be a slab of metal capable of quickly conducting heat from the processing device  230 , for instance, a 15 mm thick aluminum slab. 
     The configuration shown in  FIG. 2  also depicts the processing device  230  to be secured in the socket  210  by the heatsink adaptor  240  through at least one spring assembly  250 , the first set of fasteners  242 , and at least one bolster plate  244  before the mounting plate  260  is attached to the circuit board  220 . In this way, testing of the processing device  230 , for instance to ensure proper functioning, etc., may be easily conducted before the mounting plate  260  is attached to the circuit board  220 . 
     The mounting plate  260  may be substantially more rigid than the circuit board  220 . For example, the mounting plate  260  may be a slab of metal, such as a 15 mm thick aluminum slab which can act as a “cold plate” to cool the processing device. As such, during shocks and vibrations, the inertial force of a processing device assembly  232  (shown in  FIG. 3 ) including the heatsink adaptor  240 , the processing device  230 , the socket  210 , the spring assembly  250 , and the first set of fasteners  242  may be absorbed by the mounting plate  260 , instead of the circuit board  220 . This may decrease movement between the processing device  230  and the socket  210  which would otherwise lead to damaging effects on the pins in the socket and the landing pads on the processing device (not shown) such as fretting and pitting. Additionally, by absorbing the shocks and vibrations, the mounting plate  260  may also prevent significant bending of the circuit board  220 , which helps to prevent significant changes to the compression force applied on the processing device  230 , as well as preventing damage to the circuit board  220 . 
     The dimensions of the various elements of processing device system  200  may be designed to better accommodate manufacturing tolerances. For example, referring to  FIG. 3 , which also depicts processing device system  200 , a height A 1  or A 2  of the standoffs  262  may be different from a height B 1  or B 2  of the processing device assembly  232  including the socket  210 , the processing device  230 , the heatsink adaptor  240 , the at least one spring assembly  250 , and the first set of fasteners  242 , due to manufacturing tolerances. In this example, a lateral distance C 1  or C 2  between the standoffs  262  and the processing device assembly  232  may be chosen such that, even in the extreme case of tolerance stackup, the compression force on the processing device  230  is still within acceptable limits specified by the processing device manufacturer. 
     If the lateral distance C 1  or C 2  is too small, then tolerance stackup differences between the height A 1  or A 2 , and the height B 1  or B 2  may put large forces through the circuit board  220 , causing the circuit board  220  to bend significantly. This, in turn, may change the compression force on the processing device  230 . If the lateral distance C 1  or C 2  is too large, a significant portion of the circuit board  220  may be effectively suspended through the processing device assembly  232 . In such configurations, the inertial forces during shocks and vibrations may cause fretting and intermittent electrical connections. Thus, the lateral distance C 1  or C 2  may be a function of the difference in the tolerance stackup of the height A 1  or A 2 , and the height B 1  or B 2 , a flexibility of the circuit board  220 , and a predetermined minimum compression force required to keep the processing device  230  in the socket  210 . Thus, each of these values may be used to calculate a predetermined lateral distance C 1  or C 2 . In one example, the predetermined lateral distance C 1  or C 2  may be equal to or approximately equal to (i.e., within a predetermined threshold relative difference, such as a small percentage, 1 or 2% or more or less) the height A 1  or A 2 . 
       FIG. 4  shows another example processing device system  400  according to aspects of the disclosure. Processing device system  400  includes many of the features of processing device system  200  but with a different configuration than that shown in  FIG. 2  as discussed further below. In this example, the mounting plate  260  is used directly to secure a processing device  230  to a socket  210 . As shown, this configuration eliminates the need for a heatsink adaptor. Here, the mounting plate  260  directly applies a compression force on the processing device  230  below the mounting plate  260  to secure the processing device  230  to the socket  210 . The compression force may be controlled by at least one spring assembly  250  between the mounting plate  260  and the circuit board  220 . 
     In processing device system  400 , the mounting plate  260  is secured to the circuit board  220  through a first set of fasteners  242  and at least one bolster plate  244 . The mounting plate  260  is additionally attached to the circuit board  220  through a plurality of standoffs  262 . The standoffs  262  may allow very little movement between the mounting plate  260  and the circuit board  220 . Thus, the compression force on the processing device  230  may be better maintained during shocks and vibrations. In this example, the mounting plate  260  also has a cooling channel  266  that may circulate fluid in its interior, thereby removing excess heat from the processing device  230  to prevent damage. Alternatively, though not shown, the mounting plate  260  may have a heatsink structure on a top side of the mounting plate such that the weight of the heatsink structure is supported by the mounting plate  260 . 
     Further, as discussed above with respect to the processing device system  200 , the mounting plate  260  may be substantially more rigid than the circuit board  220  for the processing device system  400 . As such, during shocks and vibrations, the inertial force of a processing device assembly  232  including the processing device  230 , the socket  210 , the spring assembly  250 , and the first set of fasteners  242  may be absorbed by the mounting plate  260 , instead of the circuit board  220 . 
     In addition, as discussed above with respect to the processing device system  300 , lateral distances C 1  and C 2  (only A 1 , B 1 , C 1  are shown in  FIG. 4  for clarity) between the standoffs  262  and the processing device assembly  232  for the example processing device system  400  may be similarly chosen such that, even in the extreme case of tolerance stackup, the compression force on the processing device  230  is still within acceptable limits specified by the processing device manufacturer. 
     By eliminating the heatsink adaptor  240  of the processing device system  200  and, as a result, a second set of fasteners  264 , manufacturing cost of the processing device system  400  (as compared to that of processing device system  200 ) may be reduced. Further, the distance that heat must travel from the processing device  230  to the mounting plate  260  may also be reduced in processing device system  400  as compared to processing device system  200 , allowing for a more efficient heat transfer. 
     As noted above, the processing device systems  200  and  400  may be especially useful in high shock and vibration environments, such as those experienced in a vehicle. As shown in  FIG. 5 , an example vehicle  500  in accordance with one aspect of the disclosure includes various components. While certain aspects of the disclosure are particularly useful in connection with specific types of vehicles, the vehicle may be any type of vehicle including, but not limited to, cars, trucks, motorcycles, buses, recreational vehicles, etc. The vehicle may have one or more computing devices, such as computing devices  510  containing one or more processors  520 , memory  530  and other components typically present in general purpose computing devices. 
     The memory  530  stores information accessible by the one or more processors  520 , including instructions  534  and data  532  that may be executed or otherwise used by the processor  520 . The memory  530  may be of any type capable of storing information accessible by the processor, including a computing device-readable medium, or other medium that stores data that may be read with the aid of an electronic device, such as a hard-drive, memory card, ROM, RAM, DVD or other optical disks, as well as other write-capable and read-only memories. Systems and methods may include different combinations of the foregoing, whereby different portions of the instructions and data are stored on different types of media. 
     The instructions  534  may be any set of instructions to be executed directly (such as machine code) or indirectly (such as scripts) by the processor. For example, the instructions may be stored as computing device code on the computing device-readable medium. In that regard, the terms “instructions” and “programs” may be used interchangeably herein. The instructions may be stored in object code format for direct processing by the processor, or in any other computing device language including scripts or collections of independent source code modules that are interpreted on demand or compiled in advance. Functions, methods and routines of the instructions are explained in more detail below. 
     The data  532  may be retrieved, stored or modified by processor  120  in accordance with the instructions  534 . For instance, although the claimed subject matter is not limited by any particular data structure, the data may be stored in computing device registers, in a relational database as a table having a plurality of different fields and records, XML documents or flat files. The data may also be formatted in any computing device-readable format. 
     The one or more processor  520  may be any conventional processors, such as commercially available CPUs. For example, the one or more processor  520  may be configured within vehicle  500  as in any example processing device systems  200  or  400  described above, or modifications thereof. Although  FIG. 5  functionally illustrates the processor, memory, and other elements of computing devices  110  as being within the same block, it will be understood by those of ordinary skill in the art that the processor, computing device, or memory may actually include multiple processors, computing devices, or memories that may or may not be stored within the same physical housing. For example, memory may be a hard drive or other storage media located in a housing different from that of computing devices  510 . Accordingly, references to a processor or computing device will be understood to include references to a collection of processors or computing devices or memories that may or may not operate in parallel. 
     Computing devices  510  may all of the components normally used in connection with a computing device such as the processor and memory described above as well as a user input  550  (for instance, a mouse, keyboard, touch screen and/or microphone) and various electronic displays (for instance, a monitor having a screen or any other electrical device that is operable to display information). In this example, the vehicle includes an internal electronic display  552  as well as one or more speakers  554  to provide information or audio visual experiences. In this regard, internal electronic display  552  may be located within a cabin of vehicle  500  and may be used by computing devices  510  to provide information to passengers within the vehicle  500 . 
     Computing devices  510  may also include one or more wireless network connections  556  to facilitate communication with other computing devices, such as the client computing devices and server computing devices described in detail below. The wireless network connections may include short range communication protocols such as Bluetooth, Bluetooth low energy (LE), cellular connections, as well as various configurations and protocols including the Internet, World Wide Web, intranets, virtual private networks, wide area networks, local networks, private networks using communication protocols proprietary to one or more companies, Ethernet, WiFi and HTTP, and various combinations of the foregoing. 
     In one example, computing devices  510  may be control computing devices of an autonomous driving computing system or incorporated into vehicle  500 . The autonomous driving computing system may capable of communicating with various components of the vehicle in order to control the movement of vehicle  500  according to primary vehicle control code of memory  530 . For example, returning to  FIG. 5 , computing devices  510  may be in communication with various systems of vehicle  500 , such as deceleration system  560 , acceleration system  562 , steering system  564 , signaling system  566 , routing system  568 , positioning system  570 , perception system  572 , and power system  574  (i.e. the vehicle&#39;s engine or motor) in order to control the movement, speed, etc. of vehicle  500  in accordance with the instructions  534  of memory  530 . Again, although these systems are shown as external to computing devices  510 , in actuality, these systems may also be incorporated into computing devices  510 , again as an autonomous driving computing system for controlling vehicle  500 . 
     As an example, computing devices  510  may interact with one or more actuators of the deceleration system  560  and/or acceleration system  562 , such as brakes, accelerator pedal, and/or the engine or motor of the vehicle, in order to control the speed of the vehicle. Similarly, one or more actuators of the steering system  564 , such as a steering wheel, steering shaft, and/or pinion and rack in a rack and pinion system, may be used by computing devices  510  in order to control the direction of vehicle  500 . For example, if vehicle  500  is configured for use on a road, such as a car or truck, the steering system may include one or more actuators to control the angle of wheels to turn the vehicle. Signaling system  566  may be used by computing devices  510  in order to signal the vehicle&#39;s intent to other drivers or vehicles, for example, by lighting turn signals or brake lights when needed. 
     Routing system  568  may be used by computing devices  510  in order to determine and follow a route to a location. In this regard, the routing system  568  and/or data  532  may store detailed map information, for instance, highly detailed maps identifying the shape and elevation of roadways, lane lines, intersections, crosswalks, speed limits, traffic signals, buildings, signs, real time traffic information, vegetation, or other such objects and information. 
     Positioning system  570  may be used by computing devices  510  in order to determine the vehicle&#39;s relative or absolute position on a map or on the earth. For example, the position system  570  may include a GPS receiver to determine the device&#39;s latitude, longitude and/or altitude position. Other location systems such as laser-based localization systems, inertial-aided GPS, or camera-based localization may also be used to identify the location of the vehicle. The location of the vehicle may include an absolute geographical location, such as latitude, longitude, and altitude as well as relative location information, such as location relative to other cars immediately around it which can often be determined with less noise that absolute geographical location. 
     The positioning system  570  may also include other devices in communication with computing devices  510 , such as an accelerometer, gyroscope or another direction/speed detection device to determine the direction and speed of the vehicle or changes thereto. By way of example only, an acceleration device may determine its pitch, yaw or roll (or changes thereto) relative to the direction of gravity or a plane perpendicular thereto. The device may also track increases or decreases in speed and the direction of such changes. The device&#39;s provision of location and orientation data as set forth herein may be provided automatically to the computing devices  510 , other computing devices and combinations of the foregoing. 
     The perception system  572  also includes one or more components for detecting objects external to the vehicle such as other vehicles, obstacles in the roadway, traffic signals, signs, trees, etc. For example, the perception system  572  may include lasers, sonar, radar, cameras and/or any other detection devices that record data which may be processed by computing devices  510 . In the case where the vehicle is a passenger vehicle such as a minivan, the minivan may include a laser or other sensors mounted on the roof or other convenient location. Additional radar units and cameras (not shown) may be located at the front and rear ends of vehicle  500  and/or on other convenient positions. 
     The computing devices  510  may control the direction and speed of the vehicle by controlling various components. By way of example, computing devices  510  may navigate the vehicle to a destination location completely autonomously using data from the detailed map information and routing system  568 . Computing devices  510  may use the positioning system  570  to determine the vehicle&#39;s location and perception system  572  to detect and respond to objects when needed to reach the location safely. In order to do so, computing devices  510  may cause the vehicle to accelerate (for instance, by increasing fuel or other energy provided to the engine by acceleration system  562 ), decelerate (for instance, by decreasing the fuel supplied to the engine, changing gears, and/or by applying brakes by deceleration system  560 ), change direction (for instance, by turning the front or rear wheels of vehicle  500  by steering system  564 ), and signal such changes (for instance, by lighting turn signals of signaling system  566 ). Thus, the acceleration system  562  and deceleration system  560  may be a part of a drivetrain that includes various components between an engine of the vehicle and the wheels of the vehicle. Again, by controlling these systems, computing devices  510  may also control the drivetrain of the vehicle in order to maneuver the vehicle autonomously. 
     Example Methods 
     Further to example systems described above, example methods are now described. Such methods may be performed using the systems described above, modifications thereof, or any of a variety of systems having different configurations. It should be understood that the operations involved in the following methods need not be performed in the precise order described. Rather, various operations may be handled in a different order of simultaneously, and operations may be added or omitted. 
       FIG. 6  illustrates an example method  600  of assembling a socketed processing device in a high shock and vibration environment. In block  610 , a socket is attached to a circuit board. For example, the socket may be soldered onto the circuit board. In block  620 , a processing device is fitted in the socket. In block  630 , a mounting plate is attached to the circuit board so that the processing device is arranged between the circuit board and the mounting plate and that the processing device is secured to the socket by a compression force applied by the mounting plate. For example, the mounting plate may be attached to the circuit board through a first set of fasteners and at least one bolster plate. The mounting plate may be additionally attached to the circuit board through a plurality of standoffs. Further, the compression force applied by the mounting plate may be controlled by at least one spring assembly. 
       FIG. 7  illustrates another example method  700  of assembling a socketed processing device in a high shock and vibration environment. In block  710 , a socket is attached to a circuit board. For example, the socket may be soldered onto the circuit board. In block  720 , a processing device is fitted in the socket. In block  730 , a heatsink adaptor may be attached to the circuit board such that the processing device is arranged between the circuit board and the heatsink adaptor and that the processing device is secured to the socket by a compression force applied by the heatsink adaptor. For example, the heatsink adaptor may be attached to the circuit board through a first set of fasteners and at least one bolster plate. Further, the compression force applied by the heatsink adaptor may be controlled by at least one spring assembly. In block  740 , a mounting plate is attached to the circuit board. For example, the mounting plate may be attached to the circuit board through a plurality of standoffs. In block  750 , the heatsink adaptor is attached to the mounting plate. For example, the heatsink adaptor may be attached to the mounting plate through a second set of fasteners. 
     Unless otherwise stated, the foregoing alternative examples are not mutually exclusive, but may be implemented in various combinations to achieve unique advantages. As these and other variations and combinations of the features discussed above can be utilized without departing from the subject matter defined by the claims, the foregoing description of the examples should be taken by way of illustration rather than by way of limitation of the subject matter defined by the claims. In addition, the provision of the examples described herein, as well as clauses phrased as “such as,” “including” and the like, should not be interpreted as limiting the subject matter of the claims to the specific examples; rather, the examples are intended to illustrate only one of many possible examples. Further, the same reference numbers in different drawings can identify the same or similar elements.