Patent Publication Number: US-2021173457-A1

Title: Open compute project card auxiliary mode cooling

Description:
FIELD OF THE INVENTION 
     The present disclosure relates generally to cooling systems for electronic devices, and more specifically, to a system for regulating cooling device power during standby mode. 
     BACKGROUND 
     Electronic devices, such as servers, include electronic components that are connected to a power supply unit. Servers generate an enormous amount of heat due to the operation of the internal electronic components. These internal electronic components typically include controllers, processors, LAN cards, hard disk drives, and solid state disk drives. Overheating from the inefficient removal of such heat has the potential to shut down or impede the operation of the electronic components. Thus, servers are designed to rely on air flow through the interior of the device to carry away heat generated from the electronic components. Servers often include various heat sinks that are attached to the electronic components. Heat sinks are typically composed of thermally conductive material. Heat sinks absorb the generated heat from the electronic components and transfer the heat away from the components, often by permitting air flowing through or around the heat sink to absorb collected heat. This airflow is often generated by a fan system that accelerates air through or past the components and the heat sink. The generated airflow thus carries the collected heat away from the components and the heat sink. In some cases, heat can be extracted from components and heat sinks using other cooling devices, such as liquid cooling devices. 
     In typical servers, the system power for cooling such components is limited by the thermal design. Thus, the operating velocity of cooling devices is constrained by the thermal design, as components must sometimes be run at lower speeds so they don&#39;t overheat. By the principles of energy conversion, the power limitation of a fan cooled device is proportional to the air quantity flowing through the device. The greater the air quantity, the more air flow is available for cooling; and therefore, the performance of the system is increased. High system power allows for certain components, such as a CPU, to operate at higher clock speeds and/or higher power usage, thereby resulting in increased performance. Of course, greater air flow requires greater fan power, thereby increasing power requirements of the device. Various types of fans are used to provide adequate cooling. Moreover, different fan control mechanisms balance the cooling capacity and generated noise. 
     Since fan noise increases exponentially with fan rotation speed, reducing rotations per minute (RPM) by a small amount potentially results in a large reduction in fan noise. However, if the fan speed is reduced too much, components may overheat. One technique of modulating fan power is using a pulse width modulation control signal. Pulse width modulation (PWM) turns the power supply to fan-on and fan-off at a fixed frequency. Duty-cycle adjustments are made to control the speed of the fan. The larger the duty cycle, the faster the fan spins. A proper frequency must be selected since if the signal frequency is too slow, the fan&#39;s speed will noticeably oscillate within a PWM cycle. The frequency can also be too high, as commutation is done electronically using circuits that are powered by the fan&#39;s plus and minus terminals. Using PWM with the fan (and therefore the internal commutation electronics) too quickly can cause the internal commutation electronics to cease functioning correctly. In addition, the long-term reliability of the fan may be affected if the PWM rise and fall times are too fast. However, the cooling requirements for different components may vary. Such requirements are typically found in a product specification for the respective component, such as a processor, a circuit card, or a memory device. 
     Furthermore, the system power for cooling such components is limited by the system mode. In standby mode, most components are not functioning and therefore not generating heat. However, the Open Compute Project (OCP) 3.0 circuit card can consume substantial power and generate significant heat in standby mode. Standby power can be used for various functions, such as supporting wake-up functions (e.g., Wake-on-LAN), or supporting other standby functionality. When in standby mode, since active cooling devices are not powered, the OCP 3.0 circuit card is under natural convection cooling (e.g., without active airflow), thereby relying only on the natural rising of hot air and natural falling of cold air within the chassis. Further, other components in the system in standby mode or in nearby systems may produce heat that can lead to further heat build-up in the circuit card(s) of a system in standby mode. Therefore, such circuit cards may become hot from surrounding components and/or from their own standby functions. In present devices, the system fan will not power-on to cool down the OCP 3.0 circuit card when the system is in standby mode. Therefore, there is a need for a system to efficiently cool the OCP 3.0 circuit card when operating in standby mode. 
     SUMMARY 
     An electronic device operating in standby mode is provided. The electronic device includes a power supply unit, a cooling device coupled to the power supply unit, an electronic component cooled by the cooling device, and a controller coupled to the cooling device. The controller is operable to periodically monitor power data and the temperature of the electronic component in standby mode. The controller is also operable to regulate power supplied to the cooling device based on the monitored power data and temperature of the electronic component. 
     In some embodiments, the electronic component is an Open Compute Project (OCP) 3.0 circuit card. The controller can be a management controller, such as a baseboard management controller, a power management controller, or a chassis management controller. The regulation of power to the cooling device can be based on a duty cycle of a pulse width modulation signal. The electronic device can also include a second cooling device. The controller can be operative to regulate the power supplied to the second cooling device based on cooling device performance of the cooling device coupled to the power supply unit. In some embodiments, the controller is operative to determine whether the electronic component is receiving power that exceeds a power dissipation requirement of the electronic component. The controller can also be operative to periodically monitor the power data and the temperature of the electronic component in standby mode every 10 seconds. In some embodiments, the controller can be operable to increase the power supplied to the cooling device where the temperature of the electronic component exceeds a predetermined temperature threshold. 
     A method to regulate cooling device operation to cool an electronic device in standby mode is also provided herein. The electronic device includes a power supply unit, a cooling device coupled to the power supply unit, and an electronic component in standby mode. The method includes storing system cooling information in a memory device; periodically monitoring power data and the temperature of the electronic component in standby mode; and regulating power supplied to the cooling device based on the monitored power data and temperature of the electronic component. The system cooling information includes requirements of the electronic component, requirements of the system, and/or capabilities of the cooling device. 
     Additional features and advantages of the disclosure will be set forth in the description that follows, and in part, will be obvious from the description; or can be learned by practice of the principles disclosed herein. The features and advantages of the disclosure can be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the disclosure will become fully apparent from the following description and appended claims, or can be learned by the practice of the principles set forth herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which the above-recited disclosure and its advantages and features can be obtained, a more particular description of the principles described above will be rendered by reference to specific examples illustrated in the appended drawings. These drawings depict only example aspects of the disclosure, and are therefore not to be considered as limiting of its scope. These principles are described and explained with additional specificity and detail through the use of the following drawings. 
         FIG. 1  is a top view of the electronic components of an example network device, such as a server, according to certain aspects of the present disclosure; 
         FIG. 2  is a top view of electronic components on a server that have different cooling requirements, according to certain aspects of the present disclosure; 
         FIG. 3  is a schematic diagram illustrating a process for cooling an OCP 3.0 circuit card during standby mode, according to certain aspects of the present disclosure; and 
         FIG. 4  is a flow chart illustrating a process for cooling an OCP 3.0 circuit card during standby mode, according to certain aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is described with reference to the attached figures, where like reference numerals are used throughout the figures to designate similar or equivalent elements. The figures are not drawn to scale, and they are provided merely to illustrate the instant invention. Several aspects of the invention are described below with reference to example applications for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the invention. One having ordinary skill in the relevant art, however, will readily recognize that the invention can be practiced without one or more of the specific details, or with other methods. In other instances, well-known structures or operations are not shown in detail to avoid obscuring the invention. The present invention is not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts or events are required to implement a methodology in accordance with the present invention. 
       FIG. 1  is a top view of the electronic components of an example network device, such as a server  100 , according to certain aspects of the present disclosure. The server  100  includes power supply units  110  and cooling devices  112 . The power supply units  110  supply electrical power to different electronic components on the server  100 . The server  100  includes numerous electronic components that are mounted on a motherboard  114 . The electronic components generate heat when powered-on. The electronic components each have separate thermal cooling requirements to maintain operation. In this example, the electronic components include processors  120 . Other components include a hard disk drive (HDD)  126 , and a solid state disk drive (SSD)  128 . 
     The server  100  includes device sockets for additional integrated circuits and slots for the insertion of circuit cards. Each such inserted component also generates heat and requires cooling to operate. In this example, other inserted components include a series of Peripheral Component Interconnect Express (PCIe) circuit cards  130  and a series of Open Compute Project (OCP 3.0) circuit cards  132  that are inserted in a respective slot. Optional devices such as a FPGA or a LAN card may be inserted in other device sockets. A series of DIMM memory devices  136  are also provided in sockets in proximity to the processors  120 . The server can operate under three different power modes: a standby power mode, a cooling power mode as disclosed herein, and a full power mode. In some implementations of the disclosure, the server  100  can receive 12 volts of power in standby power mode. The cooling power stage can direct power (e.g., 12 volts) towards a cooling device. In the full power mode, all of systems within the server  100  are fully powered. 
     The server  100  also includes a baseboard management controller (BMC)  140  that monitors power data and other support for the electronic components of the server  100 . The server also includes a chassis management controller CMC  142  that controls the output from the power supply unit  110  and the cooling device  112 . There may be multiple electronic components of the same type. For example, the motherboard  114  of the server  100  may include additional sockets or slots for receiving additional components such as processors, cards, memory devices, and the like. The different configurations of possible electronic components that may be installed in the server  100  each have different thermal cooling requirements. 
       FIG. 2  is a top view of electronic components of a server that have different cooling requirements, in accordance with an implementation of the disclosure. The motherboard  214  can be similar to the motherboard  114  of  FIG. 1  and can be used in the server  100  of  FIG. 1 . As may be seen in  FIG. 2 , the server includes numerous electronic components that are mounted on a motherboard  214 . The electronic components generate heat when powered-on. The electronic components each have separate thermal cooling requirements to maintain operation. In this example, the electronic components include processors  220 . A series of DIMM memory devices  236  are also provided in sockets in proximity to the processors  220 . The mother-board  214  also includes open PCIe slots  250  and OCP slots  252  that allow for the addition of other components that change the thermal cooling requirements of the server. As will be explained below, in this example, the BMC  240  and CMC (e.g., the CMC  142  of  FIG. 1 ) allow for the adjustment of power for the cooling devices (e.g., cooling devices  112  of  FIG. 1 ) to optimize cooling, and adapt the cooling level when in standby mode. It should be understood that the cooling device  112  can include any type of cooling device, for example, a fan or a liquid cooling device. It should also be understood that any suitable controller with appropriate software or firmware may allow for adjustment of the cooling devices, according to the principles explained below. 
     Each of the different product specifications for different components—such as processors, memory devices, and cards—includes thermal requirements for cooling. In the present example, different techniques may be applied for adjusting cooling device power levels to provide for efficient cooling of the OCP 3.0 circuit cards (e.g., OCP 3.0 circuit cards  132  of  FIG. 1 ) in standby mode. By software or a firmware assisted cooling mechanism, the cooling device speed may be defined for the OCP 3.0 circuit cards. The cooling device speed may be used to control the power to the cooling devices, and therefore result in power saving and reducing acoustical vibration from excessive cooling device operation. In an example, fans (e.g., cooling devices  112  of  FIG. 1 ) are grouped together in two fan zones, thereby allowing for more targeted cooling and associated power settings. Thus, the same fan speed is used for two fans in a first fan zone, while a different fan speed may be used for two fans in a second fan zone. Of course, with different organization, the fan speeds for each of the fans may be controlled separately. 
     Generally, an operating memory of the controller that performs the below routine includes a supported components list that is created based on thermal limitations of the electronic components that may be installed on the devices. Some of components are hard to cool due to high power dissipation and strict thermal requirements. Other components are easier to cool because of low power dissipation and less strict thermal requirements. As a result, each component, including the OCP 3.0 circuit cards, has a specific power dissipation requirement that would indicate the thermal limitations. 
       FIG. 3  is a schematic diagram illustrating a process  300  for cooling an OCP 3.0 circuit card  332  during standby mode, in accordance with an embodiment of the disclosure. The cooling process via firmware or software may be performed in a variety of ways. One example of such cooling process is shown in  FIG. 3  for cooling an OCP 3.0 circuit card  332  (e.g., the OCP 3.0 circuit card  132  of  FIG. 1 ) and a PCIe circuit card  330  (e.g., the PCIe circuit card  130  of  FIG. 1 ) in standby mode. Process  300  can be performed using a sever, such as server  100  of  FIG. 1 . 
     In the example depicted in  FIG. 3 , standby mode (or auxiliary mode) is recognized where the server is between receiving alternative current (“AC on”) and receiving direct current (“DC on”). Standby mode can also be recognized as a complete power-off (“DC off”). During the standby mode the cooling devices  312  are typically powered-off. In some instances, the OCP 3.0 circuit card  332  receives standby power when the server is in standby mode. As generally understood, standby power refers to the electric power consumed by electronic components while they are switched-off (but are designed to draw some power) or in standby mode. 
     Once the server is in standby mode, the BMC  340  determines if the OCP 3.0 circuit cards  332  are receiving power. If the BMC  340  determines the OCP 3.0 circuit cards  332  are receiving power, the BMC  340  determines the specific power dissipation requirement of the OCP 3.0 circuit cards  332 . If the power received by the OCP 3.0 circuit cards  332  is less than the specific power dissipation requirement, the cooling devices  312  remain powered-off. 
     Alternatively, if the power received by the OCP 3.0 circuit cards  332  is determined to be more than the specific power dissipation requirement, the BMC  340  directs the CMC  342  to actuate the power supply unit  310  to enter the cooling power mode as described herein. The BMC  340  periodically monitors the power data and the temperature of the OCP 3.0 circuit cards  332 . In some embodiments, the BMC  340  monitors the temperature of the OCP 3.0 circuit cards  332  every ten seconds. Once the temperature of the OCP 3.0 circuit cards  332  exceeds a predetermined threshold, the BMC  340  directs the CMC  342  to actuate the power supply unit  310  to enter the cooling power mode as described herein. The BMC  340  periodically monitors anywhere between once every second to once every 60 seconds, but can be less frequent. The periodic monitoring can also exceed once every 60 seconds, for example, when in standby the BMC  340  periodically monitors every several minutes or hours. In some cases, the BMC  340  can monitor at a first rate when the system is in a standby power mode, but can monitor at a second rate (e.g., more or less frequent than the first rate) when in a cooling power mode. In some cases, the monitoring rate of the BMC  340  can be dependent on the temperature of the circuit card (e.g., the OCP 3.0 circuit cards  332 ) and/or the power data associated with the circuit card (e.g., the OCP 3.0 circuit cards  332 ). 
     In the cooling power mode, the CMC  342  directs the power supply unit  310  to output power to the cooling devices  312  to cool the OCP 3.0 circuit cards  332 . In this cooling power mode, the system can use more power than when in a standby power mode, but still less power than when in a full power mode. The BMC  340  can also regulate the cooling power of the cooling devices  312  (e.g., by regulating the PWM of the cooling devices  312 ) based on cooling device performance and the monitored temperature of the OCP 3.0 circuit cards  332 . For example, in the event a first cooling device  312  malfunctions, the cooling device speed of a second cooling device  312  in the same cooling device zone can be increased to account for the malfunction of the first cooling device  312 . 
       FIG. 4  is a flow chart illustrating a process  400  for cooling an OCP 3.0 circuit card (e.g., the OCP 3.0 circuit card  132  of  FIG. 1 ) during standby mode, in accordance with an embodiment of the disclosure. Process  400  can be used with a server, such as the server  100  of  FIG. 1 . The corresponding cooling device control data is stored in a memory, such as the internal memory of the BMC. The status of the BMC is first determined at steps  401  and  402 . An initial inquiry is made as to whether the BMC is disabled at step  401 . At step  402 , an inquiry is made as to whether the BMC can be launched. If the BMC is disabled, process  400  ends. If the BMC cannot be launched, process  400  returns to step  401 , where it is determined whether the BMC is disabled. Alternatively, if the BMC can be launched at step  402 , process  400  repeats at step  403 . 
     At step  403 , the BMC collects the power data and temperature of the OCP 3.0 circuit card. It should be understood that the BMC is configured to collect the server configuration requirements, and specifically, the power dissipation requirements of all the electronic components on board. At step  404 , the BMC determines if the cooling devices are receiving power from the power supply unit in standby mode. 
     If it is determined that the cooling devices are not receiving power from the power supply unit in standby mode, the process advances to step  405 . At step  405 , the BMC directs the CMC to actuate the power supply unit. The CMC directs the power supply unit to output power to the cooling devices to cool the OCP 3.0 circuit cards. 
     At step  406 , the BMC monitors the power data and the temperature of the OCP 3.0 circuit cards to adjust the cooling device speed of the cooling devices. At step  407 , the BMC also monitors the cooling device for fault identification. A determination is made at step  408  as to whether the cooling device malfunctioned. In the event the cooling device malfunctioned, the process advances to step  409  where the BMC is configured to send PWM signals to the cooling device. In this case, the cooling device speed for a second cooling device can be increased to account for the cooling loss of the malfunctioned cooling device. 
     The advantages of correlating cooling device behavior with the status of the OCP 3.0 circuit card, as compared to traditional solutions, include power saving and enhanced performance of the during operation of the device. 
     The processes  300 ,  400  of  FIGS. 3 and 4 , respectively, are representative of example machine readable instructions for a BMC and CMC (e.g., the BMC  140  and the CMC  142  of  FIG. 1 ) to set the cooling device power level. In these examples, the machine readable instructions comprise an algorithm for execution by: (a) a processor; (b) a controller; and/or (c) one or more other suitable processing device(s). The algorithm may be embodied in software stored on tangible media such as a flash memory, a CD-ROM, a floppy disk, a hard drive, a digital video (versatile) disk (DVD), or other memory devices. However, persons of ordinary skill in the art will readily appreciate that the entire algorithm and/or parts thereof can alternatively be executed by a device other than a processor and/or embodied in firmware or dedicated hardware in a well-known manner (e.g., it may be implemented by an application specific integrated circuit (ASIC); a programmable logic device (PLD); a field programmable logic device (FPLD); a field programmable gate array (FPGA); discrete logic; etc.). For example, any or all of the components of the interfaces can be implemented by software, hardware, and/or firmware. Also, some or all of the machine readable instructions represented by the processes  300 ,  400  of  FIGS. 3 and 4 , respectively, may be implemented manually. Further, although the example algorithm is described with reference to the processes  300 ,  400  illustrated in  FIGS. 3 and 4 , respectively, persons of ordinary skill in the art will readily appreciate that many other methods of implementing the example machine readable instructions may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. 
     The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof, are used in either the detailed description and/or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. Furthermore, terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein, without departing from the spirit or scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above described embodiments. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents. 
     Although the invention has been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur or be known to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.