Abstract:
In response to detecting that a power adapter, having a first power rating lower than a second power rating of an information handling system (“IHS”), is coupled to the IHS and in response to a request indicating that the IHS is to be powered on, the power adapter is decoupled from the IHS so that the IHS receives power from a battery included by the IHS.

Description:
BACKGROUND 
     The description herein relates to information handling systems capable of operating with power adapters. 
     As the value and use of information continue to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system (“IHS”) 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 information handling 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. 
     An IHS typically has a power requirement (e.g., as indicated by the IHS′ power rating). With a portable IHS (e.g., a notebook computer), power is sometimes supplied via a power adapter. Accordingly, an IHS and its associated power adapter are designed so that the power adapter&#39;s power rating is appropriate for the IHS (e.g., IHS′ power rating and the power adapter&#39;s power rating are substantially identical). 
     However, in some situations, a power adapter with an appropriate power rating may not be available for an IHS (e.g., because the IHS′ user has misplaced the power adapter). Also, in such situations, a power adapter with a power rating that is lower than the IHS′ power rating may instead be available. With a current technique, the IHS is not operable while coupled to the power adapter with a power rating that is lower than the IHS′ power rating. 
     What is needed is a method and system without the disadvantages discussed above. 
     SUMMARY 
     In response to detecting that a power adapter, having a first power rating lower than a second power rating of an information handling system (“IHS”), is coupled to the IHS and in response to a request indicating that the IHS is to be powered on, the power adapter is decoupled from the IHS so that the IHS receives power from a battery included by the IHS. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an information handling system, according to the illustrative embodiment. 
         FIG. 2  is a block diagram of a charging circuit included by the information handling system of  FIG. 1 , according to the illustrative embodiment. 
         FIG. 3  is a flow chart illustrating the operations performed by the information handling system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     For purposes of this disclosure, an information handling system (“IHS”) includes 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 information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system 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 information handling system 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 information handling system may also include one or more buses operable to transmit communications between the various hardware components. 
       FIG. 1  is a block diagram of an information handling system (“IHS”), according to the illustrative embodiment. The IHS  100  includes a system board  102 . The system board  102  includes a processor  105  such as an Intel Pentium series processor or one of many other processors currently available. An Intel Hub Architecture (IHA) chipset  110  provides the IHS system  100  with graphics/memory controller hub functions and I/O functions. More specifically, the IHA chipset  110  acts as a host controller which communicates with a graphics controller  115  coupled thereto. A display  120  is coupled to the graphics controller  115 . The chipset  110  further acts as a controller for main memory  125  which is coupled thereto. The chipset  110  also acts as an I/O controller hub (ICH) which performs I/O functions. A super input/output (I/O) controller  130  is coupled to the chipset  110  to provide communications between the chipset  110  and input devices  135  such as a mouse, keyboard, and tablet, for example. A universal serial bus (USB)  140  is coupled to the chipset  110  to facilitate the connection of peripheral devices to system  100 . System basic input-output system (BIOS)  145  is coupled to the chipset  110  as shown. The BIOS  145  is stored in CMOS or FLASH memory so that it is nonvolatile. 
     A local area network (LAN) controller  150 , alternatively called a network interface controller (NIC), is coupled to the chipset  110  to facilitate connection of the system  100  to other IHSs. Media drive controller  155  is coupled to the chipset  110  so that devices such as media drives  160  can be connected to the chipset  110  and the processor  105 . Devices that can be coupled to the media drive controller  155  include CD-ROM drives, DVD drives, hard disk drives and other fixed or removable media drives. An expansion bus  170 , such as a peripheral component interconnect (PCI) bus, PCI express bus, serial advanced technology attachment (SATA) bus or other bus is coupled to the chipset  110  as shown. The expansion bus  170  includes one or more expansion slots (not shown) for receiving expansion cards which provide the IHS  100  with additional functionality. 
     The IHS  100  also includes a general purpose input/output (“GPIO”) controller  147  which is coupled to the IHA  110 . The GPIO controller  147  is also coupled to a charging circuit  175 . The charging circuit  175  is coupled to a power adapter  185  and a battery  180 . 
       FIG. 2  is a more detailed block diagram of a charging circuit, indicated generally at  200 , that is representative of the charging circuit  175  of  FIG. 1 , according to the illustrative embodiment. The charging circuit  200  includes an alternating current/direct current (“AC/DC”) input  205 . The AC/DC input  205  is coupled to the power adapter  185  of  FIG. 1  so that the charging circuit  200  is capable of receiving power via the power adapter  185 . The charging circuit  200  also includes a switch  210 , which is coupled to the GPIO controller  147  of  FIG. 1 . Moreover, the charging circuit  200  includes a switch  220 , which is coupled to the switch  210 , and the AC/DC input  205 . In one example, one or more of the switches  210  and  220  are field effect transistors (“FET”), such as a P channel metal-oxide semiconductor FET (“MOSFET”). 
     As discussed above, the IHS  100  receives power (e.g., power supplied from a wall outlet) via the power adapter  185 . The charging circuit  200  receives such power from the power adapter  185 , and outputs to the IHS  100 . Accordingly, a system load  230  of  FIG. 2  depicts a system load that the IHS  100  exerts on the charging circuit  200 . 
     Also as discussed above, in some situations, a power adapter with an appropriate power rating (e.g., a power rating that is substantially identical to a power rating of a IHS with which the power adapter is associated) may not be available for an IHS. In this example, the power adapter  185  has a power rating that is lower than the IHS  100 &#39;s power rating. With a conventional technique, the IHS  100  is not capable of operating while coupled to the power adapter  185  to receive power. Accordingly, the IHS  100  performs the operations discussed below (in connection with  FIG. 3 ) so that the IHS  100  is capable of operating while coupled to the power adapter  185 . 
       FIG. 3  is a flow chart illustrating the operations performed by the IHS  100  of  FIG. 1 . The operation begins at a step  305 , where the IHS  100  determines whether a power adapter (e.g., the power adapter  185  of  FIG. 1 ) that is coupled to the IHS  100  has a power rating that is lower than the power rating of the IHS  100 . If the IHS  100  determines that the power rating of the power adapter  185  is not lower than the power rating of the IHS  100 , the IHS  100  also determines that the power adapter  185 &#39;s power rating is appropriate for the IHS  100 . Accordingly, in such situation, the operation ends as shown in  FIG. 3 . Conversely, if the IHS  100  determines that the power rating of the power adapter  185  is lower than the power rating of the IHS  100  as is the case with the power adapter  185  and the IHS  100 , the operation continues to a step  310 . 
     At the step  310 , the IHS  100  allows the power adapter  185  that is coupled to the IHS  100  to charge the battery  180 . Notably, although the power adapter  185 &#39;s power rating is not suitably high to supply power to the IHS  100  (e.g., so that IHS  100  is capable of being powered on with power from the power adapter  185 ), the power adapter  185  is nonetheless capable of supplying power to charge the battery  180 . After the step  310 , the operation continues to a step  315 . 
     At the step  315 , the IHS  100  self loops until it has determined that it has received a request (e.g., a signal) to power on the IHS  100 . In one example, such request is received in response to a user activating (e.g., by “pressing”) the power switch  148  of  FIG. 1 . In response to the IHS  100  determining that it has received a request to power on the IHS  100 , the operation continues to a step  320 . 
     At the step  320 , the IHS  100  decouples the power adapter  185  from the IHS  100  (e.g., the system load  230 ). In the illustrative embodiment, the power switch  148  is coupled to the GPIO controller  147  as shown in  FIG. 1 . In one version of the illustrative embodiment, in response to a user activating the power switch  148 , the GPIO controller  147  causes the switch  210  to be closed (e.g., the GPIO controller  147  drives the switch  210  “high”). In response to the GPIO controller  147  driving the switch  210  high, the switch  220  becomes open (e.g., closing of the switch  210  drives the switch  220  “low”). Accordingly, the charging circuit  200  isolates the power adapter  185  from the system load  230  so that a user activating the power switch  148  does not cause the power adapter  185  to be “latched” off. 
     Also, after the charging circuit  200  isolates the power adapter  185  from the system load  230 , the system load  230  is still coupled to the battery  180 . Accordingly, at the step  320 , the IHS  100  receives power from the battery  180 , which is capable of being charged by a power adapter (e.g., the power adapter  185 ) having a power rating lower than the IHS  100 &#39;s power rating, as shown in the step  310 . In such manner, the IHS  100  is capable of being powered on by receiving power from the battery  180 . 
     Although illustrative embodiments have been shown and described, a wide range of modification, change and substitution is contemplated in the foregoing disclosure. Also, in some instances, some features of the embodiments may be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be constructed broadly and in manner consistent with the scope of the embodiments disclosed herein.