Patent Publication Number: US-8972766-B2

Title: Power management methods and systems using an external power supply

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of pending U.S. patent application Ser. No. 12/409,001 filed Mar. 23, 2009; the contents of which is incorporated herewith in its entirety. 
    
    
     BACKGROUND 
     As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is an information handling system (IHS). An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for such systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
     For today&#39;s notebook computers and other portable electronic devices, their associated external power supplies must also be portable and be capable of operating under different load conditions. For example, different load conditions for an external power supply may exist depending on if a notebook computer is in standby mode, operating system (OS) idle or running a high performance application. Furthermore, different load conditions can exist depending on the charge level of the battery. 
     However, modern external power supplies are usually only optimized for power efficiency over a small range of load conditions. In other words, for certain load conditions, the external power supply may be relatively efficient while for other load conditions, it may be relatively inefficient. Furthermore, normal operation of an associated electronic device may not occur in the optimized range for the external power supply. For example, an AC adaptor for a notebook computer may be most efficient when operating at a 90% load rating, i.e., 90% of the maximum rated power output of the adapter. However, the notebook may rarely need such a high amount of power, and the AC adaptor may in fact frequently operate at a 10% to 20% load rating where it is much less efficient. 
     Current methods concerning external power supplies may focus on reducing power consumption when the external power supply is in an unused state. For example, if a notebook computer is switched off, an AC adaptor may be operable to reduce its power consumption since the notebook computer may need relatively little to no power. These methods, however, may not address increasing the efficiency of the external power supply while it is in operation. 
     Thus, a need exists for methods and systems for increasing the efficiency of an external power supply. 
     SUMMARY 
     The following presents a general summary of several aspects of the disclosure in order to provide a basic understanding of at least some aspects of the disclosure. This summary is not an extensive overview of the disclosure. It is not intended to identify key or critical elements of the disclosure or to delineate the scope of the claims. The following summary merely presents some concepts of the disclosure in a general form as a prelude to the more detailed description that follows. 
     One aspect of the disclosure provides for a method for managing power to an information handling system (IHS) wherein the method includes providing a battery and an external power supply operable to supply power to the IHS. The method also includes providing an application programming interface (API) to the IHS, wherein the API is configured to monitor a first parameter and a second parameter. The method further includes supplying power to the IHS via the external power supply if the first parameter reaches a first threshold level and supplying power to the IHS via the battery if the second parameter reaches a second threshold level. 
     Another aspect of the disclosure provides for an information handling system (IHS) including an external power supply, a battery, and a controller operable to select between the external power supply and the battery to supply power to the IHS. The IHS further includes an application programmable interface (API) operable to monitor a first parameter and direct the controller to select the external power supply to supply power to the IHS if the first parameter reaches a first threshold level, and wherein the API is further operable to monitor a second parameter and direct the controller to select the battery to supply power to the IHS if the second parameter reaches a second threshold level. 
     Wet another aspect of the disclosure provides a method for providing power to an information handling system (IHS). The method includes providing a battery and an external power supply operable to supply power to the IHS and providing an application programming interface (API) to the IHS, wherein the API is configured to monitor a charge capacity of the battery, an IHS power level, and a current output by the external power supply. The method further includes supplying power to the IHS via the external power supply if the charge capacity of the battery reaches a first threshold level and the IHS power level reaches second threshold level. Furthermore, the method includes supplying power to the IHS via the battery if the current output by the external power supply reaches a third threshold level. 
     A further aspect of the disclosure provides a computer-readable medium having computer-executable instructions for performing a method for managing power to an information handling system (IHS) wherein the method includes providing a battery and an external power supply operable to supply power to the IHS. The method also includes providing an application programming interface (API) to the IHS, wherein the API is configured to monitor a first parameter and a second parameter. The method further includes supplying power to the IHS via the external power supply if the first parameter reaches a first threshold level and supplying power to the IHS via the battery if the second parameter reaches a second threshold level. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For detailed understanding of the present disclosure, references should be made to the following detailed description of the several aspects, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein: 
         FIG. 1  represents an information handling system (IHS) in accordance with one aspect of the present disclosure; 
         FIG. 2  represents a schematic of an IHS configured to enable an external power supply in accordance with one aspect of the present disclosure; and 
         FIG. 3  represents a flow diagram of a method for operating an external power supply in accordance with one aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Before the present systems, methods, and computer-readable mediums are described, it is to be understood that this disclosure is not limited to the particular apparatus, systems and methods described, as such may vary. One of ordinary skill in the art should understand that the terminology used herein is for the purpose of describing possible aspects, embodiments and/or implementations only, and is not intended to limit the scope of the present disclosure which will be limited only by the appended claims. 
     It must also be noted that as used herein and in the appended claims, the singular forms “a,” “and,” and “the” may include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a circuit” refers to one or several circuits and reference to “a method of managing” includes reference to equivalent steps and methods known to those skilled in the art, and so forth. 
     For purposes of this disclosure, an embodiment of an Information Handling System (IHS) may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an IHS may be a personal computer, a storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The IHS may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the IHS may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The IHS may also include one or more buses operable to transmit data communications between the various hardware components. 
       FIG. 1  illustrates one possible implementation of an IHS  5  comprising CPU  10 . It should be understood that the present disclosure has applicability to IHSs as broadly described above, and is not intended to be limited to the IHS  5  as specifically described. The CPU  10  may comprise a processor, a microprocessor, minicomputer, or any other suitable device, including combinations and/or a plurality thereof, for executing programmed instructions. It is appreciated that execution of the algorithm to be described below occurs in the processor or the CPU  10 . The CPU  10  may be in data communication over a local interface bus  30  with components including memory  15  and input/output interfaces  40 . The system memory  15 , as illustrated, may include non-volatile memory  25 . The non-volatile memory  25  may include, but is not limited to, flash memory, non-volatile random access memory (NVRAM), and electrically erasable programmable read-only memory (EEPROM). The non-volatile memory  25  may contain a firmware program (not shown) which may contain programming and/or executable instructions required to control a keyboard  60 , mouse  65 , video display  55  and/or other input/output devices not shown here. This type of firmware may be known as a basic input/output system (BIOS). The system memory  15  may also comprise random access memory (RAM)  20 . The operating system and application programs (e.g., graphical user interfaces) may be loaded into the RAM  20  for execution. 
     The IHS  5  may be implemented with a network port  45  to permit communication over a network  70  such as a local area network (LAN) or a wide area network (WAN), such as the Internet. As understood by those skilled in the art, IHS  5  implementations may also include an assortment of ports and interfaces for different peripherals and components, such as video display adapters  35 , disk drives port  50 , and input/output interfaces  40  (e.g., keyboard  60 , mouse  65 ). 
       FIG. 2  represents a schematic illustrating a framework  200  for enabling an external power supply in accordance with one aspect of the present invention. As used herein, the efficiency of the external power supply  205  may refer to the percentage of power actually transferred from the framework  200  to the IHS  5  and not lost through heat or other energy losses. Generally, the framework  200  may enable the external power supply  205  to supply power to the IHS  5  during its most efficient load conditions. A load may generally refer to any electronic device or circuit coupled to an output of another circuit. Thus, as used herein, a load may refer to a device coupled to the output of the external power supply  205 , e.g. IHS  5 . Furthermore, a load condition may refer to the amount of current drawn by the load on the external power supply  205 . When load conditions reach levels such that the external power supply experiences a loss in efficiency, the framework  200  may then uncouple the external power supply  205  from the IHS  5  and couple the battery  245  to the IHS  5 . The battery  245  may then supply power to the IHS  5  until load conditions once again reach levels where the external power supply  205  can operate at a relatively high efficiency. At this point, the framework  200  may uncouple the battery  245  from the IHS  5  and again couple the external power supply  205  to the IHS  5  to supply power to the IHS  5   
       FIG. 2  depicts an external power supply  205  in communication with a controller  215 , battery charger  240 , battery  245 , and IHS  5 . The framework  200  may further include an application programmable interface (API)  270  in communication with the controller  215  and the battery  245 . An API may be a set of instructions, methods, procedures, protocols, and/or the like provided by an operating system (OS) or any other type of software to support requests made by a computer program to the OS. Thus, APIs may provide a standardized way for computer programs to communicate with an OS or with each other. In one implementation, the API  270  may be part of the Quickset interface. Quickset may be one example of an application that enables a user to access power management diagnostics and settings. Furthermore, the API  270  may be operable to communicate with the IHS Basic Input/Output System (BIOS) to regulate power management. 
     The external power supply  205 , by way of example, may be an Alternating Current (AC) adaptor. An AC adaptor may be a device for converting an AC voltage into a direct current (DC) voltage. The method by which an AC adaptor converts AC to DC voltage is well known in the art. Moreover, the external power supply  205  may also be capable of detecting when no load is coupled to it. Under these conditions, the external power supply  205  may toggled off or engage in “sleep mode” so as to draw relatively little power, if any, from the AC power source. 
     The controller  215 , as applied to  FIG. 2 , may be or may comprise an electronic device such as a circuit. Generally, the controller  215  may be operable to measure the power output by the external power supply via the current sense line  210 . In addition, the controller  215  may manage the charging of the battery  245  via the charger control  230 . Thus, the controller  215  may be operable to select a power source, between the external power supply  205  and the battery  245 , to supply power to the IHS  5 . Furthermore, in some implementations, the controller  215  may be embedded on the IHS  5 . 
     In instances where the battery  245  is to supply power to the IHS  5 , the API  270 , may provide a battery enable  220  signal to the controller  215 . In addition, while the battery  245  supplies power to the IHS  5 , the API  270  may monitor the charge capacity of the battery  245  and an IHS power level via the battery current and voltage sense  265  signal path. An IHS power level may refer to the amount of power that the IHS  5  is drawing from the battery  245  which may be calculated by a combination of the battery voltage and current. Furthermore, if the battery enable  220  signal is provided to the controller, the p/s enable switch  255  may be opened and the battery enable switch  250  may be closed to the voltage regulator  260 . Thus, in effect, when the battery  245  is supplying power to the IHS  5 , the external power supply  205  maybe uncoupled from the IHS  5  and not drawing any power. 
     On the other hand, during times where the external power supply  205  is to supply power to the IHS, the API  270  may provide a power supply (p/s) enable  225  signal to the controller  215 . During these instances, the API  270  may monitor a current output by the external power supply  205  via the current sense  210 . Furthermore, if the p/s enable  225  signal is provided to the controller, the controller  215  may initiate the battery charger  240  via the charger control  230  to charge the battery  245 . The controller  215  may then cause the p/s enable switch  255  to be closed to the IHS  5  and cause the battery enable switch  250  to open. Thus, when the external power supply  205  is supplying power to the IHS  5 , the battery  245  may be uncoupled from the IHS  5  and may be charging. 
     In one implementation, the framework  200  may be designed to incorporate an external power supply  205  with relatively high load efficiency. In other words, the external power supply  205  may operate at a relatively high efficiency under a relatively high load condition and operate at a relatively low efficiency for a relatively low load condition. Therefore, in such an implementation, it may be desirable to enable the external power supply  205  to supply power to the IHS  5  under relatively high load conditions so that the external power supply  205  is operational during moments where it has a relatively high efficiency. 
     For example, if the battery  245  is providing power to the IHS  5 , the API  270  may monitor the voltage or charge capacity of the battery  245  via the battery current and voltage sense  265  or any other capacity measurement device until the battery  245  reaches a threshold level such as 40% of its charge capacity. In one implementation, the framework  200  may include a Battery Management Unit (not pictured) operable to measure voltages on individual cells in the battery  245  as well as current flowing in and out of the cells. As such, when the charge on the battery  245  is at 40% of its capacity or perhaps lower, supplying current to charge the battery  245  by itself may be considered a high load condition for the external power supply  205  by the API. Indeed, at this charge capacity, the charge rate (i.e., current supplied to the battery  245  by the external power supply  205 ) may be relatively high. 
     In another implementation, even if the battery has not reached a threshold level such as 40% of its charge capacity, the API may still determine that a high load condition exists if the IHS power level reaches its own separate threshold. In either implementation, an external power supply with a relatively high load efficiency may operate at a relatively high efficiency at these threshold levels. Therefore, the API  270  may provide a p/s enable  225  signal to the controller  215  to initiate the external power supply  205  while simultaneously uncoupling the battery from the IHS and turning on the battery charger  240 . 
     The API  270  may then continue monitoring the charge on the battery  245  until the charge reaches another threshold level such as 90% of the battery&#39;s  245  capacity. In this situation, the load condition for the external power supply may be considered relatively low because the battery charge rate may need to be reduced . Thus, the API  270  may then provide a battery enable signal  220  to the controller  215  to uncouple the external power supply  205  and revert back to the battery to supply power to the IHS  5 . 
     It should be noted that while  FIG. 2  is described with references to particular percentages in charge capacity, the present disclosure is not limited to these specific percentages and may encompass a wide range of percentages. Furthermore, in other implementations, while the external power supply  270  is supplying power to the IHS  5  and charging the battery  245 , the API  270  may monitor the current output by the external power supply  205  rather than the charge on the battery  245  as a means to determine which power source to use. The API  270  may perform this function via the current sense  210  to the controller  215 . Additionally, all components illustrated in  FIG. 2  may also be embedded on the IHS  5 , excluding the external power supply  205  and the IHS  5  itself. 
     Turning now to  FIG. 3 , a flow diagram is represented that provides a method  300  for operating an external power supply coupled to an IHS in accordance with one aspect of the present invention. The method  300  begins in step  310  where the IHS uses battery power. During this time, the API may monitor a first parameter, which may include the charge on the battery, in step  320 . If the battery is good, i.e., the battery has not reached a first threshold level such as 40% of its charge capacity as described in  FIG. 2 , the API may continue to step  325 . In step  325 , the API may monitor the IHS power level. If the IHS power level is low, i.e., it remains below a separate threshold level, the IHS may continue using battery power in step  310 . However, if the charge on the battery reaches the first threshold level (e.g. 40%), or the IHS power level reaches its separate threshold level, the API may toggle on the external power supply and charge the battery in step  330 . 
     As previously mentioned, when the battery reaches the first threshold level, the external power supply may operate at a relatively high efficiency while charging the battery. Similarly, when the IHS power level reaches its threshold level, load conditions may be high enough that the external power supply can provide power to the IHS also at a relatively high efficiency. In one implementation, step  330  may be performed by coupling the external power supply to the IHS and uncoupling the battery as described in  FIG. 2 . In another implementation, the API may instead communicate with an optional control circuit within the external power supply in order to manually toggle the external power supply to an on-state, i.e. powering on the external power supply, from an off-state, i.e. a state in which the external power supply is powered off. 
     In step  340 , after the API has toggled on the external power supply, the IHS may continue to use the external power supply to draw power. Next in step  350 , the API may then monitor a second parameter, which may include the current output by the external power supply. If the current has not reached a second threshold level and is still sufficient for the external power supply to operate with a high efficiency, the IHS may continue to use the external power supply. However, if the current in fact reaches the second threshold level, the API may toggle off the power supply in step  360 , and the IHS may revert back to using battery power in step  310 . As such, the current reaching the second threshold level may indicate a relatively low current draw by the IHS. To this end, relatively low current draw may be associated with activities including, but not limited to, the IHS operating in a “sleep mode” or “hibernate state,” and/or the IHS operating in an idle state with little application activity (e.g., reading emails, document editing, and the like). 
     As previously mentioned, in one implementation, the external power supply may be uncoupled from the IHS and the battery coupled as described with reference to  FIG. 2 . In another implementation, the API may toggle off the external power supply via an optional control circuit located within the external power supply. In yet another implementation, rather than monitoring the current output by the external power supply in step  350 , the API may in fact monitor the charge on the battery as described in the framework of  FIG. 2 . Accordingly, the second threshold level would be the voltage on the battery in this situation. Thus, the method  300  may indicate a constant loop by which the API monitors the charge on the battery and the current output by the external power supply to determine which power source supplies power to the IHS. 
     As mentioned above, the external power supply may be efficient under relatively high load conditions. By toggling on the external power supply only when the charge on the battery has reached the first predetermined level, the method  300  may enable to external power supply to operate with relatively high efficiency. Furthermore, because the external power supply may be relatively inefficient under low load conditions, the method  300  may toggle off the external power supply during these moments. Thus, the overall efficiency of the external power supply when in operation may be increased. 
     It should be noted that various methods are contemplated by the present disclosure including any of the steps described herein or mentioned above, any number of repeats of any of the steps herein, and performance of the steps in any order. In addition, in reference to  FIG. 3 , both the first threshold level and the second threshold level may be a value, ratio, percentage, and/or the like as determined or set by any entity, device, application, etc. 
     Furthermore, methods of the present disclosure, detailed description and claims may be presented in terms of logic, software or software implemented aspects typically encoded on a variety of media or medium including, but not limited to, computer-readable medium/media, machine-readable medium/media, program storage medium/media or computer program product. Such media, having computer-executable instructions, may be handled, read, sensed and/or interpreted by an IHS. Generally, computer-executable instructions, such as program modules, may include routines, programs, objects, components, data structures, and the like, which perform particular tasks, carry out particular methods or implement particular abstract data types. Those skilled in the art will appreciate that such media may take various forms such as cards, tapes, magnetic disks (e.g., floppy disk or hard drive) and optical disks (e.g., compact disk read only memory (“CD-ROM”) or digital versatile disc (“DVD”)). It should be understood that the given implementations are illustrative only and shall not limit the present disclosure. 
     Although the present disclosure has been described with reference to particular examples, embodiments and/or implementations, those skilled in the art will recognize that modifications and variations may be made without departing from the spirit and scope of the claimed subject matter. Such changes in form and detail, including use of equivalent functional and/or structural substitutes for elements described herein, fall within the scope of the appended claims and are intended to be covered by this disclosure.