Patent Publication Number: US-2017373522-A1

Title: Charging System

Description:
This application claims the benefit of provisional patent application No. 62/354,025, filed Jun. 23, 2016, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to charging systems, and, more particularly, to systems for charging electronic devices. 
     Electronic devices often include batteries. A power adapter may be used to convert alternating current power into direct current power. Direct current power from a power adapter or a battery can be conveyed to electronic devices that are coupled to the power adapter using cables. Power may also be transmitted wirelessly. An electronic device that receives wired or wireless power may use the received power to operate circuitry in the electronic device and to charge a battery in the electronic device. 
     Power adapters have limited capabilities, which can make it difficult for a single power adapter to charge multiple devices. If multiple devices are plugged into a power adapter that has multiple ports, the power adapter may be overloaded and devices may not receive desired amounts of power. As a result, charging times may be longer than desired and devices with critically low battery levels may not be recharged in a timely fashion. Many power adapters are not even able to supply power to multiple devices simultaneously. 
     SUMMARY 
     It would therefore be desirable to be able to provide improved power adapters for providing power to electronic devices. 
     A system may have a power adapter with multiple ports for supplying power to respective electronic devices. The electronic devices may include devices such as cellular telephones, wristwatch devices, laptop computers, and tablet computers. The power adapter may supply power to the electronic devices using wired links and wireless links. 
     An online user account may be maintained on computing equipment in the system. The computing equipment may communicate with the electronic devices or power adapter over a communications network. The power adapter or other components in the system may gather information from the online account, from the electronic devices, and/or from the power adapter to use in identifying an optimum power transfer strategy for the power adapter to use in transferring power to each of the electronic devices. The optimum power transfer strategy may involve transmitting different amounts of power to different electronic devices. 
     The information that is used in identifying appropriate amounts of power to transmit to each of the electronic devices may include information such as user device charging priority settings, battery charge state information, device type information, usage history information, calendar information, and other information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative system that includes a power adapter and electronic devices that receive power from the power adapter in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of an illustrative power adapter having circuitry that provides wired power to an electronic device in accordance with an embodiment. 
         FIG. 3  is a schematic diagram of an illustrative power adapter having circuitry that provides wireless power to an electronic device in accordance with an embodiment. 
         FIG. 4  is a flow chart of illustrative steps involved in identifying and using optimum power transfer settings to supply power to electronic devices from a power adapter in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Equipment such as a power adapter may be used to supply power to multiple electronic devices. Power may be supplied in accordance with user-defined preferences and information on device type, device status, device usage history, and other information. For example, a power adapter may preferentially supply power to device such as a wristwatch based on knowledge of the device type (wristwatch), based on battery status (the battery in the wristwatch is critically low), based on usage history (the wristwatch is typically used heavily in the evening so charging in the late afternoon is essential), based on user-defined charging priority settings (i.e., user preferences that give priority to, e.g., the user&#39;s wristwatch over, e.g., the user&#39;s cellular telephone), and/or based on other criteria. In this way, the power adapter can optimize the delivery of scarce power among multiple competing devices. 
       FIG. 1  is a diagram of a system with a power adapter that may supply power to multiple electronic devices. As shown in  FIG. 1 , system  10  may include a power adapter such as power adapter  14 . Power adapter  14  may be coupled to a source of power such as alternating current (AC) power source  12 . Power source  12  may be a wall outlet or other source of line power. If desired, power adapter  14  may receive direct current (DC) power from a source such as battery  13 . 
     Power adapter  14  may include an AC-DC power converter such as converter  16 . Converter  16  may convert AC power from source  12  into DC power. DC power from converter  16  and/or DC power from battery  13  may be distributed to circuitry within power adapter  14  such as power transmission circuits  18 . Power transmission circuits  18  may be associated with respective power ports  19 . Power ports  19  may supply power to corresponding electronic devices  24  via wired and/or wireless links  21 . 
     Control and communications circuitry  20  may be used to control the operation of power transmission circuits  18 . For example, circuitry  20  may be used to adjust the relative amounts of power supplied by first and second power transmission circuits  18  to first and second respective electronic devices  24  (e.g., so that the first electronic device receives more power from adapter  14  than the second electronic device or so that the second electronic device receives more power from adapter  14  than the first electronic device). If, for example, power adapter  14  has a maximum capacity of 40 W, 30 W of power may be allocated to the first device and 10 W may be allocated to the second device. 
     Circuitry  20  may include communications circuitry that communicates with electronic devices  24  over wired or wireless paths. For example, circuitry  20  may include wireless transceiver circuitry that is coupled to one or more antennas  22  for wirelessly transmitting and/or receiving signals. This allows circuitry  20  to receive information that is used in determining how to allocate power between devices  24 . 
     Electronic devices  24  may include power reception circuits  26  for receiving power from respective power transmission circuits  18  over corresponding links  21 . Control and communications circuitry  28  in devices  24  may be used to control the operation of devices  24  and may be used to communicate with external equipment. For example, communications circuitry in devices  24  may be used to communicate with communications circuitry in circuitry  20  of adapter  14  wirelessly or via wired paths. In some configurations, electronic devices  24  may be coupled to case such as case  30  (e.g., a cover, supplemental battery pack, or other accessory that has a battery such as battery  32  to provide an electronic device  24  with extra battery capacity). 
     Computing equipment  36  may include one or more servers or other computing equipment and may be coupled to power adapter  14  and/or electronic devices  24  via communications network  34 . Communications network  34  may include one or more wired and/or wireless paths (e.g., internet links, local area network links, cellular telephone links, etc.). Equipment  36  may include communications circuitry for communicating with communications circuitry in power adapter  14  and devices  24 . Equipment  36  may maintain online accounts for users of devices  24 . A user may log into an online account using one of electronic devices  24  or other computing equipment (e.g., to adjust preferences, to register new electronic devices  24 , etc.). During operation of devices  24 , usage data (e.g., device usage history such as information on what time of day devices  24  are used and how much power is consumed as a function of time and date) and other information on the status and operation of devices  24  may be maintained in equipment  36  and/or may be communicated to other devices  24  and/or adapter  14 . This information and other information may be used in system  10  to determine how much power should be provided to each of devices  24  over links  21 . 
     Power adapter  14  may have ports that supply wired power. As shown in  FIG. 2 , port  19  in power adapter  14  may have an associated wired power transfer circuit ( 18 ) with voltage regulator and switching circuitry  38 . Voltage regulator and switching circuitry  38  may contain circuitry for controlling the current and voltage of power signals supplied to electronic device  24  over wired path  21 . Electronic device  24  may have charger circuitry  40 , battery  42 , and system circuitry  44 . Charger circuitry  40  may contain control circuits (e.g., switching circuitry, voltage regulator circuitry, etc.) for controlling the routing of power that has been received from path  21  to battery  42  and system circuitry  44 . Battery  42  may be a rechargeable battery that is housed in a common housing with system circuitry  44  and, if desired, may be supplemented by an auxiliary battery (e.g., a battery in an external case such as battery  32  of case  30  of  FIG. 1 ). When a battery (i.e., a battery such as battery  42  that is mounted in the housing of device  24  or an auxiliary battery coupled to device  24 ) is depleted, charger circuitry  40  may, if desired, route power from path  21  to the battery to charge the battery. 
     Charger circuitry  40  may also route power from path  21  to system circuitry  44  to power components in system circuitry  44 . System circuitry  44  may include electrical components that provide device  24  with processing and input-output capabilities. For example, system circuitry  44  may include control circuitry such as microprocessors, memory, application-specific integrated circuits, communications circuitry, and other circuits, may include sensors, displays, keyboard, touch screens, and may include other input-output components that work in conjunction with the control circuitry, etc. 
     If desired, some or all of ports  19  may supply wireless power. As shown in  FIG. 3 , port  19  in power adapter  14  may have an associated power transfer circuit  18  based on wireless power transmission circuitry  41 . Wireless power transmission circuitry  41  may include wireless power transmitter  43  (e.g., a transmitting circuit that produces alternating current signals) and an associated wireless power transmission device (antenna) such as coil  47 . Wireless power may be transferred from power adapter  14  to device  24  using near-field and far-field techniques, may be transferred using microwave transmissions, may be transmitted using resonant inductive coupling, may be transmitted using capacitive coupling, or may be transmitted using other suitable techniques. In the illustrative example of  FIG. 3 , wireless power transmitter  43  is using wireless power transmission coil  47  (i.e., an inductor formed from one or more loops of wire or other signal paths) to transmit power wirelessly to device  24  via inductive charging 
     During inductive charging operations, transmitter  43  produces alternating current signals that are supplied to coil  47  and that cause coil  47  to produce electromagnetic signals  46  (alternating magnetic fields) that are conveyed to a corresponding wireless receiving element such as coil  45  in device  24  via path  21 . Coils such as coils  47  may be arranged in an array (e.g., in a two-dimensional array of rows and columns of coils  47 ) or other suitable configuration (e.g., to incorporate coils  47  into an inductive charging mat that includes power adapter  14 , to incorporate coils  47  into a housing of an electronic device such as a computer, to incorporate coils  47  into a bag, or to incorporate coils  47  into other equipment). 
     The use of inductive charging using an array of coils  47  (each of which may potentially supply wireless power to a respective device  24 ) is illustrative. Other types of wireless charging schemes may be used by adapter  14  to supply wireless power to device  24 , if desired. The circuitry of adapter  14  may be housed in a single housing (e.g., a metal or plastic housing) and/or may be housed within multiple housings. As an example, part of adapter  14  may be housed in a cube-shaped enclosure and another part of adapter  14  (e.g., coils  47  and, if desired, associated transmitters  43 ) may be housed in another housing (e.g., a thin mat-shaped housing or other housing). A cable may be used to couple the coils and transmitter circuitry in the mat portion of this type of adapter to the main adapter unit. 
     As shown in  FIG. 3 , device  24  may include wireless power receiver circuitry  52 . Wireless power receiver circuitry  52  may receive wireless power from adapter  14  and may use the receive power to charge an internal battery (e.g., battery  42 ) and/or a battery in a case that is coupled to device  24 . Wireless power from adapter  14  may also be used to power system circuitry  44 . 
     In the example of  FIG. 3 , wireless power is being transferred via inductive charging, so wireless power receiver circuitry  52  includes receiver  50  and coil  45  for receiving electromagnetic signals (magnetic fields)  46  from adapter  14 . In other types of wireless charging schemes, coil  45  may be replaced with a capacitive electrode (e.g., in capacitive coupling wireless power schemes), may be replaced by a microwave antenna (e.g., in a far-field or near-field microwave wireless charging scheme), etc. The power received by coil  45  may be converted to DC power by receiver  50  and supplied to charger circuitry  40 . Charger circuitry  40  may supply power to battery  42  to charge battery  42  and/or may supply power to system circuitry  44 . 
     The maximum amount of power that adapter  14  can deliver over wired and wireless links  21  is limited. For example, adapter  14  may be rated to deliver 100 W of power, may be rated to deliver 50-150 W of power, may deliver a limited amount of power over 10 W of power, or may deliver less than 200 W of power. Because the ability of adapter  14  to supply power to devices  24  is limited, it is desirable to intelligently optimize the transfer of power to devices  24 . User preferences, device usage history, battery state information and other device status information, and other information may be used in identifying an optimum power transfer strategy (e.g., an optimum charging strategy in scenarios in which each of devices  24  includes a battery to be charged). The circuitry of system  10  may be dynamically configured to implement the optimum power transfer strategy. The optimum power transfer strategy may favor one device over another so as to ensure that appropriate device(s)  24  have power. The power transfer strategy used by adapter  14  may, if desired, evolve over a period of time. For example, after critical charging operations that favor one device have been performed, power delivery settings for ports  19  may be adjusted to favor a different device and/or to balance power delivery among multiple devices. 
     A user may provide system  10  with user power transfer preferences using any suitable user input scheme. As an example, one or more of devices  24  may contain touch screen displays or other input devices. Control circuitry in devices  24  can use input-output circuitry in devices  24  to gather user input (e.g., by gathering responses to on-screen options, by gathering button press input, etc.). User input may also be supplied to equipment  36  (e.g., from a web browser). If desired, user input may be supplied to power adapter  14  using a touch screen, keyboard, buttons, voice command input interface, or other input-output circuitry in adapter  14 . User input and other information that is gathered using devices  24 , computing equipment  36 , and/or adapter  14  may be stored in adapter  14 , may be stored in device(s)  24 , and/or may be stored in computing equipment  36 . 
     As an example, device  24  may have a settings screen with which a user supplies device  24  with user-defined charging preferences (sometimes referred to as device charging priority information) or other power delivery settings. As another example, device  24  or other computing equipment may be used to log into an online account associated with computing equipment  36 . Once logged into the account, the user may use a web browser or other interface to supply computing equipment  36  with power delivery preferences. As yet another example, adapter  14  may be used to gather power delivery preferences directly from a user or from device  24  and may store these preferences in control circuitry  20  of adapter  14 . 
     Another potential source of information for use in identifying an optimum power delivery strategy is data that is stored in equipment such as adapter  14  and/or devices  24  by default. For example, device identifiers (device IDs) and other device information may be embedded into the circuitry of devices  24  during manufacturing. The device information may include serial numbers, model numbers, device type identifiers, device capability information (e.g., maximum charging power capabilities), and other device-specific information. By determining which type of device is being provided with power, power delivery may be further optimized (e.g., critical devices such as wristwatches may be favored over other devices such as media players). Device type information and other device-specific information may be gathered by adapter  14  from devices  24  (e.g., using wired and/or wireless links between adapter  14 ) and/or may be gathered by adapter  14  from devices  24  via computing equipment  36 . Computing equipment  36  and devices  24  may also gather device type information and adapter type information from devices  24 , equipment  36 , and/or adapter  14 . 
     The state of battery charge on the batteries used by devices  24  (e.g., internal batteries  42  and/or case batteries  32 ) may be used in determining charging priorities. For example, if the battery in a first device is nearly full and the battery in a second device is nearly empty, power may, at least initially, be delivered primarily to the second device. If desired, user preferences, device type, and other information may be used to override charging priorities based on battery state. For example, if a user has indicated that the first device is of primary importance or if the first device is of a type known to be critical (e.g., a wristwatch), the first device may be provided with power while the second device is provided with no power or less power (at least until the battery in the first device has been completely charged). 
     Another type of information that may be used in determining power delivery settings is device usage history information. A user may routinely deplete most of the battery of a device (e.g., a tablet computer) during an operating period extending from 3:00 to 5:30 PM on Mondays through Fridays (e.g., because this is a particular time of day and particular set of days during the week in which the user desires to watch video, play games, or perform other energy intensive tasks). The user may also routinely use another device (e.g., a wristwatch) upon waking at 7:00 AM every day of the week. Yet another device of the user (e.g., a cellular telephone) may be used primarily from 8 AM to 10 PM. The times at which the user is able to couple devices  24  to power adapter  14  to receive power may vary from day to day. 
     By collecting and maintaining device usage information for each of the user&#39;s devices  24  (e.g., a watch, cellular telephone, and tablet in this example), power delivery can be optimized among these devices. If, for example, the battery level of all devices is moderate and the devices are all coupled to adapter  14  at 2:00 PM, power delivery to the tablet computer (which is known to need extensive battery power from 3:00 to 5:30 PM) may be prioritized. Only after sufficient power has been provided to the tablet computer to charge the battery of the tablet computer sufficiently for the anticipated use of the tablet computer from 3:00 to 5:30 PM will significant power be routed to the wrist watch and cellular telephone. If, as another example, all devices are able to receive power from adapter  14  at 11:30 PM, adapter  14  may supply power to all of devices  14  equally, so that all devices are freshly charged overnight. Device usage history may, if desired, be used to prioritize power delivery to a first device (e.g., a tablet computer that is about to be used) over a second device (e.g., a cellular telephone) even if the battery of the first device is more charged than the battery of the second device. As with other types of information, user preferences may, if desired, be used to override power delivery priorities based on usage history information. 
     Links  21  may have different efficiencies. For example, wired power delivery links may be more efficient at delivering power (i.e., may deliver power with fewer parasitic losses) than wireless links. Links  21  may also have power delivery capacities that vary. For example, a first link may have a maximum power delivery rating of 10 W and a second link may have a maximum power delivery capability of 100 W. The charging circuits of devices  24  may also vary in efficiency between devices. In general, charging efficiency and capacity may be affected by the circuitry of adapter  14 , the circuitry of devices  24 , and/or environmental conditions (e.g., device placement in a wireless power scenario), causing different ports  19  of adapter  14  to be associated with different power transfer efficiencies. 
     Information on the capabilities of ports  19 , links  21 , and/or devices  24  (the power transfer efficiency of links  21  and/or the maximum rated charging power supported by devices  24 ) may be taken into account in optimizing power delivery. For example, even though it might otherwise be preferable to give preference to supplying power to a first device over a second device, power delivery to the second device may be given priority in scenarios in which power delivery through the adapter port associated with the first device is impaired (e.g., if link efficiency for the link associated with the first device is less than a predetermined threshold value, etc.). If desired, tests may be performed dynamically to evaluate power transfer efficiency. For example, the amount of battery charging that can be achieved for a given amount of power supplied to each port  19  may be measured by transferring trial amounts of power to devices  24  through each of ports  19  and a power delivery strategy may be optimized based on these battery charging characterization measurements. If for example, a particular battery has been prematurely aged due to exposure to high temperatures, it may be difficult to charge that battery efficiently and this information may therefore be taken into account in devising an optimum power transfer strategy. 
     In some situations, the systems of devices  24  may consume power during charging operations. As an example, a user may desire to use a tablet computer while the tablet computer is being powered using power from adapter  14  but may not need to power a display or otherwise actively use the systems in a wristwatch or cellular telephone that are coupled to adapter  14 . In situations such as these, the devices that do not require significant system power (e.g., devices with inactive displays such as the wristwatch and cellular telephone in this example) may be supplied with less power than a device that has an active display (i.e., the tablet computer in this example). The optimization of the power delivery to devices  24  in this type of scenario may therefore take into account both battery charging requirements (based on battery state, usage history, device type, user preferences, etc.) and system usage requirements (as an example, adapter  14  may supply 1 W of power or less to devices with no active display and 10 W of power or more to devices with displays, wireless circuits, and/or processors that are actively being used by the user). 
     To prevent premature battery aging, it may be desirable to periodically allow the charge state of charged batteries to drop below 100%. For example, after a battery has been completely charged, it may be desirable to cease further charging until the battery charge level for the battery has dropped below 95% (or other suitable threshold value). This approach may be used, for example, to help preserve battery life. In some scenarios, battery charging strategy may be directed towards minimizing energy waste. For example, it may be desirable to charge a battery so that the battery reaches full charge right before a device is to be used. Battery charge state history information may therefore be used in conjunction with other battery information (e.g., current charge state, battery capacity, battery chemistry type, other battery type information, etc.) in determining how to optimize power delivery to devices  24  in system  10  (e.g., to preserve battery life, to minimize wasted energy, etc.). Battery charge state information may be gathered using circuitry in devices  24  such as charger circuitry  40 . Other battery information may be stored in devices  24  during manufacturing (e.g., using a battery type identifier, etc.) or battery information may be obtained by using a database on computing equipment  36  or in adapter  14  to associate particular types of batteries with particular types of devices (which may be identified using a model number or other device information). 
     Devices  24  and other equipment (e.g., a user account maintained on remote computing equipment such as equipment  36  of  FIG. 1 ) may maintain calendar information. Calendar entries in a calendar may be created by a user with a web browser or other user interface (e.g., user input arrangements associated with devices  24 ). Calendar information and other information that is gathered in system  10  may be used to predict future device usage. If, for example, a user is scheduled to be out of the office on a particular day, it may be concluded (as a default or by correlation with device usage history information) that the user will be traveling and will use a particular device (e.g., a cellular telephone) more than usual. When charging devices  24  in advance of the out-of-office period, more power may therefore be transferred to the cellular telephone than to other devices  24  to ensure that the cellular telephone is adequately charged. 
     Information on which software applications have been installed on devices  24  may also be used in predicting device power requirements. If, for example, a large number of power-intensive applications have been installed on a particular device, it can be concluded that the device has power requirements (i.e., battery reserve requirements) that are above average. As with the other information used in identifying an optimum power delivery strategy, information on which software applications have been installed on the control circuitry of devices  24  may be maintained on one or more of devices  24 , on the control circuitry of adapter  14 , and/or on control circuitry associated with remote equipment such as computing equipment  36 . 
     In identifying an optimum power transfer strategy for adapter  14 , power transfer optimization software may be run on the circuitry of adapter  14 . For example, the circuitry of adapter  14  may be configured to gather information such as user preferences, usage history, device type, battery information, etc., and may be configured to identify how much power to provide to each of ports  19  (i.e., power transfer level settings for each of ports  19 ) so that optimum amounts of power are provided to each of devices  24  over links  21 . If desired, circuitry in devices  24  and/or remote circuitry such as control circuitry in computing equipment  36  may be used instead of using circuitry in adapter  14  or may be used in conjunction with the circuitry of adapter  14  to identify an optimum power transfer strategy. 
     Illustrative operations involved in using system  10  to identify an optimum power transfer strategy for devices  24  and in using the strategy to supply power to devices  24  are shown in  FIG. 4 . 
     During the operations of block  60 , information for use in identifying an optimum power transfer strategy may be collected using the equipment of system  10  ( FIG. 1 ) and may be distributed throughout system  10 . At step  62 , the information that has been gathered at step  60  and/or other information may be used in identifying an optimum power delivery strategy that may be used by adapter  14  in transferring power to devices  24  via ports  19 . As indicated by line  64 , processing may then loop back to step  60  so that additional information for optimizing power delivery may be gathered. 
     Step  60  may include information gathering operations at step(s)  78  and data distribution operations at step  80 . In general, information may be gathered using any of the resources of system  10  (e.g., information may be gathered using computing equipment  36 , devices  24 , and/or power adapter  14 ). As an example, each device  24  that is in communication with adapter  14  may, during the operations of step(s)  78 , supply adapter  14  with information over a wired or wireless communication path between circuitry  28  in that device  24  and circuitry  20  in adapter  14  (e.g., links  21  or other links). Adapter  14  may gather information from computing equipment  36  via network  34 . 
     If desired, user input may be gathered at step  66 . User input may include user preferences such as user-defined device-type charging priorities, user-defined location-based charging priorities, user-defined charging priorities associated with particular times of day and/or for particular devices, or other user-defined power transfer settings. As an example, a user may specify that the user&#39;s watch should always be charged before the user&#39;s tablet computer, regardless of the state of charge on the watch or tablet. As another example, a user may set up more complex charging preferences (e.g., “charge my watch before my tablet so long as my tablet has at least a 25% battery charge level” or “charge my cellular telephone to 100% Sunday night before charging any other devices if my calendar indicates that I will be out of the office on Monday,” etc.). User preferences may be gathered using touch screens, keyboards, and other input-output circuitry (circuitry  28 ) on devices  24  and may be stored in devices  24 . User preferences may also be gathered by computing equipment  36  (e.g., using a web browser on one of devices  24  or other electronic equipment that communicates with equipment  36  via communications network  34 ). Power adapter  14  may also have input-output devices (e.g., buttons, touch screens, or other input-output circuitry associated with control circuitry  20 ) for gathering user input. 
     At step  68 , battery information may be gathered. Battery information may include a battery charge level (battery state) for the battery in each of devices  24  (and, if desired, information on the charge state of the battery in any associated cases such as case  30  of  FIG. 1 ). In addition to gathering information on how much each battery is charged, information on battery health may be gathered (e.g., battery age, battery usage history, battery type, battery capacity in mAh, battery temperature, etc.). 
     At step  70 , device type information may be gathered for devices  24 . For example, a serial number, device identifier, device type identifier, model number, or other information identifying which types of devices  24  are present in system  10  and are available to receive power from adapter  14  may be gathered. 
     At step  72 , device usage history information may be gathered. For example, information may be gathered on which applications are used in each of devices  24 , information may be gathered on the power consumption of each of devices  24 , information may be gathered on the battery charging history of devices  24 , information may be gathered on screen brightness settings, wireless communications circuitry usage, other information on the use of components in devices  24  that consume significant amounts of power, and other information on the use of devices  24 . Device usage information may include information on the time of day and date (e.g., day of week, day of month, etc.) associated with component usage (i.e., power consumption versus time/date information). Global positioning system data (i.e., satellite navigation system data gathered using circuitry  28  in devices  24 ) and/or other location information may be associated with component usage. For example, the device usage history information that is gathered at step  72  may indicate that a bright screen setting is routinely used for a device between 4 and 5 PM on weekdays, that wireless circuitry for web browsing and cellular telephone calls is used evenly throughout the week between 7 AM and 6 PM when the device is within 10 miles of the user&#39;s home and is used heavily between 6 AM and 9 PM when the device is more than 10 miles from the user&#39;s home, that charging typically takes place two or three times per week between 7 PM and 9 PM, and that media is played back by a media player application routinely at 3 PM each day, consuming significant power. Usage information may be correlated with device location, time and date information, device user identity information (e.g., when a given device is shared among multiple potential users), and other information. 
     At step  74 , calendar information may be gathered. For example, a user may maintain a calendar on device(s)  24  and/or on online (e.g., on computing equipment  36 ). The entries in the calendar may include information on the user&#39;s future location (e.g., vacation or business meetings out of town, appointments in the user&#39;s hometown, etc.), may include information on the user&#39;s future activities (e.g., vacation may be correlated with heavy media playback activities, work may be associated with heavy wireless use, travel to bright locations at certain times of the year may involve the use of bright screen settings, etc.). 
     System  10  may perform tests and gather other information at step  76 . As an example, adapter  14  may transfer default amounts of power to each of the devices that is coupled to adapter  14  to determine how effectively the batteries in the devices can be charged. These battery charging tests may reveal, for example, that some devices are relatively easy to charge (e.g., because the batteries in those devices are healthy, because the power transfer links to those devices and/or the circuitry at the transmit and receive ends of the links are efficient, etc.) and may reveal that other devices are relatively difficult to charge (e.g., because those devices have unhealthy batteries, are associated with poor link efficiencies, etc.). In addition to performing tests to ascertain link efficiency (battery charging efficiency) for each of ports  19  and each of the devices  24  coupled to ports  19 , system  10  may periodically perform other tests and may be used in gathering additional data that may be used in developing an optimum power transfer strategy. Information that is gathered at step  76  and during the other operations of step  78  may be gathered continuously (e.g., whenever adapter  14 , devices  24 , and/or computing equipment  36  are running), may be gathered in accordance with a schedule (e.g., once per hour), may be gathered when suitable criteria (e.g., user-defined criteria and/or predetermined default criteria) have been satisfied, or may be gathered in accordance with any other suitable data gathering protocol. 
     During the operations of step  80 , information that has been gathered in system  10  may be shared among the components of system  10 . As an example, user device charging priority settings and other user preferences that have been gathered during user interactions with an online account maintained by computing equipment  36 , calendar data, and other data may be transferred to power adapter  14  from computing equipment  36 . As another example, calendar information, battery charge state information, device usage information, user preferences, device type, and other information that has been gathered during a user&#39;s interactions with devices  24  may be transferred from devices  24  to power adapter  14 . Information may also be shared between devices  24  and computing equipment  36  (e.g., by synching calendar data between devices  24  and computing equipment  36 , by uploading device usage history from devices  24  to computing equipment  36  to reduce storage burdens on devices  24 , etc.). If desired, adapter  14  may transfer information to devices  24  and/or computing equipment  36  (e.g., information on device charging preferences that a user supplied directly to adapter  14  may be provided to an online account on equipment  36  and/or to a user preferences application running on devices  24 ). These techniques for sharing information between the devices in system  10  are illustrative. Other types of information sharing arrangements may also be used, if desired. 
     At step  62 , system  10  may process the information gathered at step  60  and other information (e.g., information on the current time and date, information on the current locations of the devices in system  10 , etc.) to identify optimum power transfer settings for adapter  14  to use in transferring power to devices  24  through ports  19 . In determining which power transfer settings to use (i.e., in determining how many watts of power to transfer over each of lines  21  and therefore how much power to use in charging each of devices  24 ), the processing circuitry of power adapter  14  (and/or processing circuitry in devices  24  and/or computing equipment  36 ) may take into consideration competing desires. For example, it may generally be desirable to give charging preference to those devices  24  that have heavily depleted batteries, as this will help prevent scenarios in which one or more of devices  24  become unusable due to lack of battery power. Nevertheless, user device charging priority information or considerations based on device history usage, device type, link efficiency, predictions based on calendar information, test results, or other information may make it beneficial to override this general desire. If, as one example, a first of devices  24  is a critical device such as a watch and a second of devices  24  is a less critical device such as a media player, it may be desirable to preferentially charge the first device. This type of consideration, which is based on device type information, may be overridden by user preferences that specify that charging priority should be given to the media player over the watch. 
     Adapter  14  or other equipment in system  10  may be used to weigh these competing demands and identify an optimum power transfer strategy. For example, adapter  14  may analyze factors such as user preferences (e.g., priority settings that specify desired priorities for charging devices  24 ), battery information (battery health, battery capacity, battery charge level, etc.), device type (e.g., media player, cellular telephone, watch, laptop computer, tablet, etc.), device charging capabilities (e.g., the maximum rated charging power supported by each device), device usage history information (e.g. information on power consumption levels correlated with time of day, day of week, device location, device user, and other device usage history information), calendar information, and test results and other information. In analyzing these factors, adapter  14  may use weighting schemes and other decision algorithms techniques in determining how much power to transmit through each of ports  19  (i.e., how much power to transfer to each of devices  24 ). Adapter  14  may then adjust the settings of power transfer circuits  18  (and, if desired, may direct devices  24  to adjust power receiving circuits  26  and/or other device components such as charger circuitry  40 , system circuitry  44 , etc.) so that appropriate amounts of power are transferred to each of devices  24  over links  21  to operate the system circuitry in each of devices  24  and/or to charge the batteries in each of devices  24 . The amounts of power that are transferred may be less than the maximum rated charging power supported by each device, may favor a second device over a first device based on user charging preferences or other information (e.g., so that the second device receives its maximum rated charging power and so that the first device receives less than its maximum rated charging power), may sometimes cause less fully charged devices to be provided with more power than devices that are more fully charged, may sometimes cause less fully charged devices to be provided with less power than devices that are more fully charged, may sometimes provide electronic devices with amounts of power that are based on device type rather than user preferences, may sometimes provide electronic devices with amounts of power that are based on user preferences rather than device type, may sometimes provide electronic devices with amounts of power that are based on multiple weighted factors such device type, user preferences, calendar information, and other information, etc. 
     The operations of  FIG. 4  may be performed by the control circuitry in adapter  14 , in devices  24 , and/or in computing equipment  36 . During operation, this control circuitry (which may sometimes be referred to as processing circuitry, processing and storage, computing equipment, a computer, etc.) may be configured to perform the methods of  FIG. 4  (e.g., using dedicated hardware and/or using software code running on hardware in adapter  14 , devices  24 , and/or computing equipment  36 ). The software code for performing these methods, which may sometimes be referred to as program instructions, code, data, instructions, or software, may be stored on non-transient (tangible) storage media in the control circuitry of adapter  14 , devices  24 , and/or computing equipment  36  such as read-only memory, random-access memory, hard drive storage, flash drive storage, removable storage medium, or other computer-readable media and may be executed on processing circuitry such as microprocessors and/or application-specific integrated circuits with processing circuits in the control circuitry of adapter  14 , devices  24 , and/or computing equipment  36  to perform the processes of  FIG. 4 . 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.