Abstract:
An adapter including an associated battery capable of powering an electronic device. The power adapter typically includes the battery as an integral component that is connected to a plug or other interface capable of mating with a power source, such as a wall socket. Thus, the adapter battery may provide power either to operate the device or charge a battery within (or otherwise associated with) the device even if the adapter is not connected to a power source.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates generally to power supplies for supplying power to portable electronic devices having a rechargeable battery, and more specifically to a power adapter including a rechargeable adapter battery. 
       BACKGROUND 
       [0002]    Rechargeable batteries may be found in a variety of portable electronic devices, including laptop computers, personal digital assistants (PDAs), cell phones, digital media players, cameras, etc. The rechargeable battery in such devices is typically charged using power supplied from a power adapter connected to an external power source. The power adapter may also be configured to provide power to run the device, in conjunction with charging the internal battery. 
         [0003]    Existing adapters do not include an battery source for powering electronic devices and/or powering an internal battery. As such, users desiring additional battery power will typically purchase an external battery that can be separately connected to the portable electronic device. However, such external batteries are generally cumbersome to use, at least because they must be unpacked for use and then repacked for storage. In addition, many users may forget to bring the external battery in addition to the adapter while in transit. 
         [0004]    What is needed is a way to combine a power adapter and a battery so that a user does not have to carry an additional external battery while traveling with a portable electronic device. 
       SUMMARY 
       [0005]    Generally, embodiments discussed herein provide power to an electronic device from a battery external to the device but associated with a power adapter. The power adapter typically includes the battery as an integral component that is connected to a plug or other interface capable of mating with a power source, such as a wall socket. Thus, presuming the adapter is plugged into the electronic device, the adapter battery may provide power either to operate the device or charge a battery within (or otherwise associated with) the device even if the adapter is not connected to a power source. 
         [0006]    Further, the adapter may include a processor, such as a microcontroller, that may execute logical operations to intelligently determine how to distribute charge between the adapter battery and device battery, based at least in part on an operating state of the device. The adapter processor may communicate with a processor inside the device and, in some embodiments, the device processor may assist in such logical operations or may perform the operations and instruct the adapter processor accordingly. Thus, the adapter may vary its charging function depending on operating variables not only of the adapter itself, but also those of the device to which it is connected. 
         [0007]    One embodiment takes the form of an apparatus for providing power to an electronic device, including: a processor; a battery operatively connected to the processor; a power output operatively connected to the battery and configurable to be connected to the electronic device; a relay operatively connected to the battery and the processor; and a power input operatively connected to the battery and the relay. 
         [0008]    Another embodiment takes the form of a method for powering an electronic device from an adapter having an internal adapter battery The method may include the following operations: determining if the adapter is connected to a power source; in the event the adapter is connected to the power source, determine if the device is connected to the adapter; in the event the device is connected to the adapter, operating the device from the power source; and in the event the device is not connected to the adapter, charging the internal adapter battery. 
         [0009]    These and other embodiments and features will be apparent to those of ordinary skill in the art upon reading this disclosure in its entirety, along with the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  illustrates an embodiment of a power adapter having a rechargeable battery coupled to an electronic device. 
           [0011]      FIG. 2  is a block diagram of the embodiment of the power adapter and electronic device shown in  FIG. 1 . 
           [0012]      FIGS. 3A-3B  are a flow diagram illustrating the power adapter and electronic device of  FIG. 1  in various stages of use. 
           [0013]      FIG. 4  is a block diagram of another embodiment of an electronic device having multiple rechargeable batteries. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    A portable electronic device, such as a laptop computer, may include an internal battery to provide power for several hours of operation while the laptop computer is not connected to an external power source. Generally, in order to continue operation once the internal battery is depleted, one must recharge the battery, replace it, or connect the portable electronic device to a power source such as an electrical outlet. Further, many portable electronic devices are sealed and so a user cannot replace the internal battery, or at least cannot do so easily. 
         [0015]    An adapter having its own internal battery may be connected to a portable electronic device to provide power to operate the device once its battery is depleted. In some embodiments, the adapter and the electronic device may each include respective microcontroller units that are configured for sharing information, such as battery charge and power source information, between the various internal hardware components, as well as between the electronic device and the adapter. 
         [0016]    It should be noted that an adapter with an internal battery, as described herein, may be used with any appropriately-configured portable electronic device or non-portable device, for that matter. Suitable electronic devices include, but are not limited to, mobile telephones, portable computers, tablet computing devices, input/output devices, portable video players, portable televisions, personal digital assistants, headphones, and so on. 
         [0017]    As shown in  FIGS. 1 and 2 , in one embodiment, an electronic device  12  having a rechargeable internal battery  38  may be connected to a power adapter  10  having a rechargeable adapter battery  11 . The power adapter  10  may also be connected to a power source  17  via a plug  20 . The sample electronic device  12  shown in  FIG. 1  and discussed herein is a portable computer, but it should be understood that any of the aforementioned devices may be appropriately configured and substituted. In addition, the power source  17  may be any source of electrical power, including a direct current (DC) power source, although an alternating current (AC) source is illustrated in  FIG. 1 . 
         [0018]    The adapter  10  may include an output connector  24  connecting the adapter  10  to the electronic device  14 , as well as an input power line  16  connecting the adapter  10  to the external power source  17 . In some embodiments, the adapter may further include an outer housing  18  for protecting the internal components of the adapter  10 , and the input power line  16  may include a cord coupled to a plug  20  configured for plugging into the external power source  17 . In other embodiments, the plug  20  may extend directly from the housing  18 , rather than from a cord. 
         [0019]    The output connector  24  may include a plug that may be received by a receiving port on the electronic device  14  (port not shown). In some embodiments, the plug may include a quick release mechanism that enables the plug to disengage from the receiving port if it is tugged on, for instance by someone tripping over the output cord. In addition, the output connector  24  may further include a light indicator, such as a light-emitting diode (LED), configured to indicate the battery charge state, e.g., charging or fully charged, of the adapter battery  11  and/or the internal rechargeable battery  38  in the electronic device  12 . One connector that may be used in conjunction with an embodiment of the power adapter  10  is the MAGSAFE connector manufactured by Apple Inc. 
         [0020]      FIG. 2  is a block diagram schematically illustrating some of the internal components of the power adapter  10  and electronic device  12  shown in  FIG. 1 . As shown in  FIG. 2 , the electronic device  12  may include an internal device microcontroller unit  34  and an internal charger  36 , as well as an internal rechargeable internal battery  38 . The device microcontroller unit  34  may be connected to the internal charger  36  and the internal battery  38 , as well as to the adapter microcontroller unit  32  of the adapter  10 . In some embodiments, the device microcontroller unit  34  may also be connected to a wireless control device  37  configured to receive and transmit information to the adapter microcontroller unit  32  of the adapter  10 . The internal charger  36  may be connected to the internal rechargeable battery  38 , as well as to the adapter  10  through a power line  24  configured to supply voltage from the adapter  12  to the charger  36 . 
         [0021]    Additionally, the internal charger  36  may be connected, either wirelessly or through physical communication channels, to the other components of the electronic device  12  in order to direct power to these components when the adapter  10  is connected to an external power source  17  (as shown in  FIG. 1 ). The internal battery  38  may also be connected to the other components of the electronic device  12  to supply battery power to these components when, for example, the electronic device  12  is not connected to the adapter  10  and/or the adapter  10  is not connected to an external power source. 
         [0022]    In one embodiment, the device microcontroller unit  34  may include one or more inputs that receive data from the internal battery  38  and the adapter microcontroller unit  32  of the adapter  10 . For example, in one embodiment, the device microcontroller unit  34  may be configured to receive information from the internal battery  38  indicating the charge level of the battery  38 . Continuing the example, the charge level may be reported in various states indicating if the battery  38  is very low, low, adequate or fully charged. As will be described more fully below, the device microcontroller unit  34  may also be configured to receive information from the adapter microcontroller unit  32  indicating the level of charge of the adapter battery  11  and/or whether the adapter  10  is connected to an external power source. As shown in  FIG. 2 , this information may be sent via a physical communication channel  17  or through a wireless control device  37 . Additionally, the device microcontroller unit  34  may include one or more sensors for measuring and monitoring the power being supplied from the adapter  10  to the electronic device  12  via power line  24 . 
         [0023]    The device microcontroller unit  34  may likewise include one or more outputs for transmitting information to the adapter microcontroller unit  32 . For example, the device microcontroller unit  34  may be configured to transmit the charge level received from the internal battery  38  to the adapter microcontroller unit  32  of the adapter  10 , either through a physical communication channel  17  or a wireless control device  38 . 
         [0024]    The device microcontroller unit  34  also may include a control line outputting a control signal to the internal charger  36 ; the microcontroller  34  typically generates this control signal. The control signal may enable the charger  36  to either begin or stop charging the internal battery  38 . The control signal may be based on the charge level information received from the adapter microcontroller unit  32  regarding the adapter battery  11 , whether the adapter  10  is connected to an external power source and/or the charge level information received from the internal battery  38 . 
         [0025]    As shown in  FIG. 2 , the power adapter  10  may include a converter  22 , a relay  26 , a charger  30 , a rechargeable internal battery  11 , a adapter microcontroller unit  32 , a boost converter  13 , a power switch  14 , a voltage regulator  15 , and/or one or more universal serial buses  18  (USB). 
         [0026]    In one embodiment, the converter  22  is connected to the external power source  17  (as shown in  FIG. 1 ) via an input power line  16 , which may include a cord and an associated plug  20 . The converter  22  may convert AC voltage received from the power source  17  into DC voltage that is usable by the other components in the adapter  10 , as well as by the electronic device  12 . Additionally, the converter  22  may be connected to a relay  26  that is configured to supply voltage either from the converter  22  to the charger  30  to charge the adapter battery  11  or directly from the converter  22  to the power switch  14 , bypassing the charger  30  and the battery  11 . As will be discussed in more detail below, the determination as to whether voltage is supplied directly to the power switch  14  or through the charger  30 , battery  11  and the boost converter  13  is made by the adapter microcontroller unit  32 . 
         [0027]    In some embodiments, the power adapter  10  may include an additional input configured to receive power from a trickle power source  21 , such as a solar or photovoltaic cell, supplying a trickle voltage. As shown in  FIG. 1 , the trickle power source  21  may be connected to the charger  30  so as to supply voltage to the charger  30  and/or the power switch  14 , while bypassing the converter  22 . 
         [0028]    As shown in  FIG. 2 , relay  26  may be set so that voltage is supplied from the converter  22  to the charger  30 . In one embodiment, the charger  30  may be configured to supply a current to the adapter battery  11  to charge the battery  11 . The charger  30  may also be configured to supply voltage from the battery  11  to a boost converter  13 , which in turn may be configured to convert the voltage received from the battery  11  to output a higher DC voltage. The boost converter  13  may, in turn, be connected to the power switch  14 . 
         [0029]    The power switch  14  may be configured to receive voltage directly from the converter  22  (via relay  26 ) or from the boost converter  13 . Further, the power switch  14  may be connected to the internal charger  36  of the electronic device  12  by the power connector  24 , initially discussed with respect to  FIG. 1 . The power switch  14  may further be configured to supply voltage to an additional port provided in the adapter  10 , such as a USB port  18  configured to receive a secondary portable electronic device, such as a cellular phone and/or a portable media player. Examples of suitable such devices include an iPod or an iPhone, as currently manufactured by Apple Inc. A voltage regulator  15  may regulate the voltage outputted by the power switch  14  in order to maintain a constant voltage level, thereby preventing or minimizing damage to the secondary device caused by sudden voltage increases in the external power source (as well as ensuring the voltage level is sufficient to operate or charge the secondary device). 
         [0030]    Still with respect to  FIG. 2 , a adapter microcontroller unit  32  may be electrically connected to various components of the power adapter, including the power switch  14 , the boost converter  13 , the charger  30 , the adapter battery  11 , the relay  26  and/or the converter  22 . The adapter microcontroller unit  32  may also be connected via a control line  17  to the internal device microcontroller unit  34  of the electronic device  12 . In some embodiments, the adapter microcontroller unit  32  may also be wirelessly connected via a wireless control device  37  to the internal device microcontroller unit  34  of the electronic device  12 . 
         [0031]    The adapter microcontroller unit  32  may include a microprocessor, a program memory in the form of a NOR flash or ROM, as well as an EEPROM (or other erasable storage mechanism). Additionally, the microcontroller unit may further include other functional components, such as a crystal oscillator, timers, watchdog, serial and analog I/O, etc. As would be appreciated by one of skill in the art, the microcontroller  32  may be fabricated on a single integrated chip, or may include components located on multiple chips. 
         [0032]    The adapter microcontroller unit  32  may include a plurality of inputs and/or outputs for receiving information regarding various components within the adapter  10  and/or controlling these components. For example, in one embodiment, the adapter microcontroller unit  32  may be configured to receive information from the converter  22  indicating whether the converter  22  is receiving voltage from the input power line  16 , i.e., whether the adapter  10  is receiving power from an external power source. Additionally, the adapter microcontroller unit  32  may be configured to receive information from the adapter battery  11  indicating the charge level of the battery  11 , for example, whether the battery is very low, low, adequate and/or fully charged. The adapter microcontroller unit  32  may further include an additional input for receiving information from the internal device microcontroller unit  34  of the electronic device  12 , such as the charge level of the internal battery  36  of the electronic device  12 . 
         [0033]    The adapter microcontroller unit  32  may also control and/or monitor various functions of the adapter  10 . For example, the device microcontroller unit  34  may be configured to transmit the charge information received from the adapter battery  11  to the internal device microcontroller unit  34 , either through a physical communication channel  17 , or through a wireless control device  38 . In addition, the adapter microcontroller unit  32  may transmit control signals to the charger  30 , boost converter  13 , relay  26  and/or power switch  14  based on information received from the converter  22 , the adapter battery  11 , and/or the internal device microcontroller unit  34  of the electronic device  12 . 
         [0034]    Continuing the discussion, the adapter microcontroller unit  32  may be connected to the adapter charger  30  by a control line. The adapter microcontroller may generate and transmit a control signal instructing the charger  30  to either begin or stop charging the adapter battery  11 , as necessary or desired. In addition, the adapter microcontroller unit  32  may also control operation of the boost converter  13 , the relay  26  and power switch  14 . Thus, opening and closing of relay  26  and power switch  14  is generally under the control of the adapter microcontroller, which may thus direct power to flow directly from the converter  22  to the device  12  or through the charger  30 , battery  11 , and boost controller  13 . 
         [0035]      FIG. 3A  is a flowchart illustrating one method for supplying power between an electronic device and an adapter having a battery if the adapter is connected to a power source, but the electronic device is not connected to the adapter. Initially, in operation  302  the embodiment may determine whether the adapter has been connected to an external power source. Referring to  FIG. 2 , this operation is typically performed by the adapter microcontroller unit  32  of the adapter  10 , which receives information from the converter  22  indicating whether the adapter  10  is connected to the external power source  17 . 
         [0036]    If, in operation  302 , the embodiment determines that the adapter is connected to an external power source, it may determine whether the electronic device is connected to the adapter in operation  304 . This determination may be made by either the device microcontroller unit  34 , which receives information from the internal charger  36  indicating whether the electronic device  12  is connected to the adapter  10  via the power line  24 , or the adapter microcontroller unit  32 . It should be noted that operation  304  may be optional in certain embodiments or may occur prior to operation  302 , in which case operation  320  may be omitted. 
         [0037]    If in operation  304  the embodiment determines that the electronic device is not connected, then operation  314  is executed and the embodiment will charge the adapter battery from the external power source. This operation is generally performed via the adapter microcontroller unit  32  which is configured to transmit a control signal to the relay  26  to supply voltage from the converter  22  to the adapter charger  11 . The adapter microcontroller unit  32  is further configured to transmit a control signal to the adapter charger  30  enabling the charger  30  to charge the adapter battery  11 . Following operation  314 , the method ends in end state  346 . 
         [0038]    Continuing the discussion of  FIG. 3A , as previously mentioned, in operation  304  the embodiment determines if the electronic device is connected to an external power source. If the embodiment determines that the electronic device is connected to an external power source, then operation  306  is accessed and the embodiment will run the electronic device from the external power source. 
         [0039]    Referring back to  FIG. 2 , if the adapter microcontroller unit  32  receives an indication that the adapter  10  is connected to a power source and the device microcontroller unit  34  of the electronic device  12  receives an indication that the electronic device  12  is connected to the adapter  10 , the adapter microcontroller unit  32  may transmit a control signal to the relay  26  to supply voltage from the converter  22  directly to the power switch  14 , bypassing the charger  30  and the boost converter  13 . The adapter microcontroller unit  32  may also transmit a control signal to the power switch  14  to supply voltage received from the relay  26  to the adapter  12 . 
         [0040]    Turning back to  FIG. 3A , operation  308  is executed after operation  306 . In operation  308 , the embodiment will determine whether there is excess power available in light of the power requirements necessary to operate the device. This determination is made by the device microcontroller unit  34  of the electronic device  12 , which may include sensors for monitoring the power supplied to the internal charger  36  from the adapter  12  via the power line  24 . If there is insufficient power for any operation beyond supplying power to the device, then operation  318  is accessed and the embodiment will not charge the internal battery. Accordingly, the embodiment and will continue to only run the computer from the external power supply. Referring to  FIG. 2 , if the device microcontroller unit  34  of the electronic device  12  determines that there is insufficient power to charge the internal battery  36 , the microcontroller  34  will transmit a control signal to the internal charger  36  to disable charging of the internal battery  36 , and to provide power received from the adapter  10  to power the other components of the electronic device  12 . 
         [0041]    Following the execution of operation  315 , the method ends in end state  346 . 
         [0042]    It may alternately be determined in operation  308  that the available power is sufficient to charge the internal battery. If so, the embodiment proceeds to operation  310  and the internal battery is charged. 
         [0043]    Next, in operation  312 , the embodiment determines if there is still sufficient available power to charge the adapter battery. This determination may be made by the device microcontroller unit  34  or the adapter microcontroller. If, in operation  312 , there is sufficient available power to charge the adapter battery, then in operation  314  the embodiment will charge the adapter battery. As mentioned above, this operation is performed via the adapter microcontroller unit  32  which is configured to transmit a control signal to the relay  26  to supply voltage from the converter  22  to the adapter charger  11 , as well as transmit a control signal to the adapter charger  30  to charge the adapter battery  11 . 
         [0044]    If, in operation  312 , if there is not sufficient available power to charge the adapter battery, then in operation  315  the embodiment will not charge the adapter battery. Referring to  FIG. 2 , if the device microcontroller unit  34  of the electronic device  12  determines that there is insufficient power to charge the adapter battery  11 , the microcontroller  34  will transmit this information to the adapter microcontroller unit  32 , which in turn will transmit control signals to relay  26  and power switch  14  to supply voltage directly from the converter  22  to the charger  36  of the electronic device  12 , bypassing the charger  30  and boost converter  13 . 
         [0045]    After either operation  314  or  315 , the method terminates in end state  346 . 
         [0046]    The discussion of  FIG. 3A  now returns to operation  302 . If the embodiment determines that the adapter is not connected to an external power source in this operation, then, in operation  320 , the embodiment determines whether the electronic device is connected to an external power source. Referring to  FIG. 2 , this may be accomplished by the microcontroller  34  of the electronic device  12 , which may receive information from the charger  36  indicating whether the charger  36  is connected to the adapter  10 . It should be noted that operation  320  may be optional in certain embodiments or may occur prior to operation  302 . 
         [0047]    If, in operation  320 , the embodiment determines that the adapter is not connected to an external power source, then operation  322  is executed and the embodiment will conserve power of both the adapter battery  11  and the internal battery  38 . This may be accomplished in the embodiment shown in  FIG. 2  by the microcontroller units  34 ,  32  of the electronic device  12  and the battery  12 , which may transmit respective control signals to the chargers  36 ,  30  to disable charging of the batteries  11 ,  38 . After operation  322 , the method ends in operation  346 . 
         [0048]      FIG. 3B  is a flowchart illustrating another portion of the method initially discussed with respect to  FIG. 3A . A positive determination in operation  320  of  FIG. 3A , as discussed above, results in the embodiment entering operation  324  of  FIG. 3B . In operation  324 , the embodiment determines whether the internal battery is at a low charge level. For example, referring to  FIG. 2 , operation  324 , the microcontroller  34  of the electronic device  12  may be configured to receive a signal from the internal battery  38  indicating a level of charge of the battery  38 . The value of a “low charge level” may be set by the manufacturer or may, in certain embodiments, be user-specified. As one example, a 25% charge level may be considered low. 
         [0049]    If, in operation  324 , the embodiment determines that the internal battery is not at a low charge level, then operation  326  is performed. In operation  326 , the embodiment determines whether the adapter battery is at a low charge level. As previously mentioned, this operation may be performed by the microcontroller  32  of the adapter  10 , which is configured to receive a signal from the adapter battery  11  indicating a level of charge of the battery  11 . 
         [0050]    If, in operation  326 , the embodiment determines that the adapter battery is at a low charge level, then in operation  332 , the embodiment will run the electronic device from its internal battery. Referring to  FIG. 2 , this may be accomplished by the device microcontroller unit  34  of the electronic device  12 , which may transmit a control signal to the charger  36  to disable charging, as well to the internal battery  38  to supply power to the other components of the electronic device  12 . Following operation  332 , the method terminates in end state  346 . 
         [0051]    If, however, in operation  326 , the embodiment determines that the adapter battery is not at a low level, then in operation  328 , the embodiment will run the electronic device from the adapter battery. Although this may not be the most efficient use of power, since power will be lost as it is transferred from the adapter battery to the computer battery, this operation provides a practical benefit, in that internal battery power of the electronic device is preserved. Referring to  FIG. 2 , this operation may be performed by transmitting a control signal from the device microcontroller unit  34  of the electronic device  12  to the internal charger  36  to supply voltage to the internal battery  38 . The adapter microcontroller unit  32  of the adapter  10  may also transmit a control signal to the adapter charger  30  enabling the charger  30  to supply voltage from the battery  11  to the boost converter  13 . In addition, the adapter microcontroller unit  32  may further transmit additional control signals to the boost converter  13  and the power switch  14  to perform their respective functions. Following operation  328 , the method terminates in operation  346 . 
         [0052]    Returning to operation  324 , the embodiment may determine that the internal battery is at a low charge level. If so, operation  330  is accessed and the embodiment determines if the internal battery is at a very low charge level. Again, this may be determined by the microcontroller  34  of the electronic device  12 , which receives information from the internal battery  38  indicating the charge level of the battery  38 . As with the low battery level, the “very low” battery level may be specified by a third party such as a manufacturer or may be user-specified. As one example, a 10% charge may be a very low battery charge level. 
         [0053]    If, in operation  330 , the embodiment determines that the internal battery is at a very low level, then operation  334  is executed and the embodiment determines if the adapter battery is also at a low level. This may be determined by the microcontroller  32  of the adapter  10 , which may receive information from the adapter battery  11  indicating whether the charge level of the battery  11  is very low. 
         [0054]    If, in operation  334 , the embodiment determines that the adapter battery is at a low level, then operation  336  is accessed and the embodiment will force the adapter and the electronic device to go into sleep mode, or to shut down. This may be accomplished in the embodiment shown in  FIG. 2  by transmitting a control signal from the adapter microcontroller unit  32  to the adapter charger  30  to disable charging of the adapter battery. Similarly, the device microcontroller unit  34  of the electric device  12  may also transmit a signal to the charger  36  to disable charging of the internal battery  38 . Further, the microcontroller unit may transmit a control signal to the other components of the electronic device  12  to initiate shut down or power off procedures for the electronic device  12 . After operation  336 , the method terminates in end state  346 . 
         [0055]    On the other hand, if the embodiment determines in operation  334  that the adapter battery is not at a low level, then in operation  338 , the embodiment will charge the internal battery from the adapter battery. As previously described with respect to operation  328 , this may be accomplished via the device microcontroller unit  34  of the electronic device  12 , which may transmit a control signal to the internal charger  36  to supply voltage to the internal battery  38 . Following operation  338 , end state  346  is entered. 
         [0056]    Returning to operation  330 , the embodiment may determine that the internal battery is not at a very low level. In this case, the embodiment executes operation  340  and determines if the adapter battery is at a low level. As previously described, this may be accomplished by the adapter microcontroller unit  32  of the adapter  10 , which is configured to receive information indicating a charge level of the adapter battery  11 . 
         [0057]    If, in operation  340 , the embodiment determines that the adapter battery is at a low level, then in operation  336 , the embodiment will force the adapter and the electronic device to go into sleep mode, or to shut down. By contrast, if the embodiment determines that the adapter battery is not at a low level in operation  340 , then the embodiment will run the electronic device from the adapter battery in operation  328 . The implementation of these operations, for example, in the embodiment illustrated in  FIG. 2 , may be the similar to that previously discussed with respect to steps  334 ,  336  and  338 . 
         [0058]    Generally, the foregoing methods of operation have been described and indication has been provided as to what components execute certain operations. It should be appreciated that either microcontroller unit  34 ,  36  may accomplish or execute functionality described herein that is ascribed to the other unit with appropriate configuration. Likewise, various other operations ascribed to particular hardware elements may be carried out by different elements. Accordingly, the foregoing discussion of particular operations being carried out by particular hardware is provided for illustration only. 
         [0059]      FIG. 4  illustrates another embodiment of an electronic device  700  having two batteries  703 ,  705  that are located inside the housing  701  of the device  700 . Each battery  703 ,  705 , may be connected to a charger  707  configured to charge the batteries  703 ,  705 . In other embodiments, there may be more than one charger  707  provided in the electronic device  700  for example, the device  700  may include one charger  707  provided for each battery  703 ,  705  of the device  700 . A microcontroller unit  709  may be connected to the charger  707  and configured to enable the charger  707  to charge the batteries  703 ,  705  by supplying voltage received through an input power line  16  that may include a cord and a corresponding plug  20  connected to a power supply  17 . Although an electronic device  700  is illustrated in  FIG. 7 , one of ordinary skill in the art will appreciate that the present invention also encompasses an adapter having multiple battery packs. 
         [0060]    Although the present invention has been described with respect to particular embodiments and methods of operation, it should be understood that changes to the described embodiments and/or methods may be made yet still embraced by alternative embodiments of the invention. For example, certain embodiments may omit or add operations to the methods and processes disclosed herein. Accordingly, the proper scope of the present invention is defined by the claims herein.