PATENT DOCUMENT

Publication Number: US-11121590-B1
Application Number: US-202017028404-A
Country: US
Kind Code: B1

Title: Wireless power system with communications

Abstract:
A wireless power system may include an accessory configured to transfer or relay wireless power to a portable electronic device. The portable electronic device may include wireless charging circuitry and sensors configured to detect compatible accessories currently coupled with the portable electronic device. The portable electronic device performs wireless charging or related functions in accordance with the coupled accessories.

Claims:
What is claimed is: 
     
       1. An electronic device operable with an accessory, the electronic device comprising:
 a wireless charging coil; 
 near-field communications circuitry having a near-field communications antenna around the wireless charging coil; 
 a magnetic alignment structure configured to align the near-field communications antenna with a corresponding near-field communications antenna in the accessory and to align the wireless charging coil with a corresponding wireless charging coil in the accessory when the magnetic alignment structure is magnetically coupled to the accessory; 
 a magnetic sensor configured to detect when the magnetic alignment structure is magnetically coupled to the accessory, wherein the near-field communications circuitry is configured to receive information from the accessory in response to detecting that the magnetic alignment structure is magnetically coupled to the accessory; and 
 an output device configured to present an icon associated with the accessory using the received information, wherein the icon comprises an icon selected from a group consisting of: a wireless charging mat icon, a wireless charging puck icon, a removable case icon, a battery case icon, and a dock icon. 
 
     
     
       2. The electronic device of  claim 1 , wherein the near-field communications antenna runs along a peripheral edge of the wireless charging coil and wherein the magnetic alignment structure runs along a peripheral edge of the near-field communications antenna. 
     
     
       3. The electronic device of  claim 1 , wherein the output device comprises a display configured to present, using the received information, the icon associated with the accessory. 
     
     
       4. The electronic device of  claim 1 , wherein the output device comprises a display configured to present, using the received information, a physical characteristic associated with the accessory. 
     
     
       5. The electronic device of  claim 4 , wherein the physical characteristic comprises a color of the accessory. 
     
     
       6. The electronic device of  claim 1 , wherein the output device comprises a display configured to present, using the received information, a functionality associated with the accessory. 
     
     
       7. The electronic device of  claim 6 , wherein the functionality comprises an operating mode that varies depending on a location of the accessory. 
     
     
       8. The electronic device of  claim 1 , wherein the output device comprises a display configured to present, using the received information, ownership information associated with the accessory. 
     
     
       9. The electronic device of  claim 1 , wherein the near-field communications circuitry is further configured to perform authentication operations with the accessory, and wherein the near-field communications circuitry is configured to receive unprotected data before the authentication operations and to receive protected data after the authentication operations. 
     
     
       10. The electronic device of  claim 9 , further comprising:
 control circuitry configured to perform wireless power handshake operations with the accessory, wherein the authentication operations is performed while temporarily pausing the wireless power handshake operations. 
 
     
     
       11. The electronic device of  claim 9 , wherein the wireless charging coil is configured to receive wireless power signals from the accessory during wireless power transfer operations, and wherein the authentication operations are performed while temporarily halting the wireless power transfer operations. 
     
     
       12. An electronic device operable with an accessory, the electronic device comprising:
 a wireless charging coil; 
 near-field communications circuitry having a near-field communications antenna; 
 a magnetic alignment structure configured to align the wireless charging coil with a corresponding wireless charging coil in the accessory when the magnetic alignment structure is magnetically coupled to the accessory, wherein the magnetic alignment structure and the wireless charging coil form concentric structures; 
 a magnetic sensor configured to detect when the magnetic alignment structure is magnetically coupled to the accessory, wherein the near-field communications circuitry is configured to receive information from the accessory in response to detecting that the magnetic alignment structure is magnetically coupled to the accessory; and 
 an output device configured to present an output associated with the accessory using the received information. 
 
     
     
       13. The electronic device of  claim 12 , wherein the near-field communications antenna and the wireless charging coil form concentric structures. 
     
     
       14. The electronic device of  claim 12 , wherein the near-field communications antenna runs along a peripheral edge of the wireless charging coil. 
     
     
       15. The electronic device of  claim 12 , wherein the magnetic alignment structure runs along a peripheral edge of the near-field communications antenna. 
     
     
       16. The electronic device of  claim 12 , wherein the magnetic alignment structure runs along a peripheral edge of the wireless charging coil. 
     
     
       17. The electronic device of  claim 12 , wherein the magnetic sensor comprises a multi-axis magnetic sensor. 
     
     
       18. The electronic device of  claim 17 , wherein the multi-axis magnetic sensor is configured to detect an orientation of the accessory when the magnetic alignment structure is magnetically coupled to the accessory.

Description:
This application claims the benefit of provisional patent application No. 63/075,035, filed Sep. 4, 2020, which is hereby incorporated by reference herein in its entirety. 
     FIELD 
     This relates generally to power systems, and, more particularly, to wireless power systems for charging battery-powered electronic devices. 
     BACKGROUND 
     In a wireless charging system, a wireless power transmitting device such as a charging mat wirelessly transmits power to a wireless power receiving device such as a battery-powered, portable electronic device. The wireless power transmitting device has a coil that produces electromagnetic flux. The wireless power receiving device has a coil and rectifier circuitry that uses electromagnetic flux produced by the transmitter to generate direct-current power that can be used to power electrical loads in the battery-powered portable electronic device. 
     SUMMARY 
     A wireless charging system includes an electronic device operable with an accessory. In accordance with some embodiments, the electronic device can include a wireless charging coil, near-field communications circuitry having a near-field communications antenna around the wireless charging coil, a magnetic alignment structure configured to align the near-field communications antenna with a corresponding near-field communications antenna in the accessory when the magnetic alignment structure is magnetically coupled to the accessory, a magnetic sensor configured to detect when the magnetic alignment structure is magnetically coupled to the accessory, and an output device. The near-field communications circuitry can be configured to retrieve information from the accessory in response to detecting that the magnetic alignment structure is magnetically coupled to the accessory. The output device can be configured to present an output associated with the accessory using the retrieved information. 
     The near-field communications antenna can run along an inner or outer peripheral edge of the wireless charging coil. The magnetic alignment structures can run along an inner or outer peripheral edge of the near-field communications antenna. The output device can be a display configured to present a wireless charging mat icon, a wireless charging puck icon, a removable case icon, a battery case icon, a dock icon, a physical characteristic such as a color of the accessory, a functionality associated with the accessory, and ownership information associated with the accessory. The output device can also provide audio, haptic, or other visual feedback when the device attaches to the accessory. Near-field communications can be performed while wireless power handshake operations are paused or while wireless power transfer operations are halted. 
     In accordance with some embodiments, a method of operating an electronic device with an accessory is provided. Such method can include using a magnet to magnetically attract a corresponding magnet in the accessory, using a magnetic sensor to detect when the magnet is magnetically attracting the corresponding magnet in the accessory, using near-field communications circuitry to receive information from the accessory in response to detecting that the magnet is magnetically attracting the corresponding magnet in the accessory, and using a display to display an output associated with the accessory based on the retrieved information. The method can further include using a wireless charging coil to receive wireless power signals from the accessory and charging a battery with the wireless power signals. The method can further include performing near-field communication authentication operations while wireless power handshake operations are temporarily paused or while active wireless power transfer is temporarily halted. 
     In accordance with some embodiments, an electronic device operable in a wireless power system to receive wireless power signals from a power transmitting device is provided. The electronic device can include a wireless power receiving coil configured to receive the wireless power signals, a near-field communications reader with a near-field communications antenna that runs along a peripheral edge of the wireless power receiving coil, a magnet at least partially surrounding the near-field communications antenna, where the magnet is configured to magnetically coupled to a corresponding magnet in the power transmitting device to align the wireless power receiving coil with a wireless power transmitting coil in the power transmitting device, and a magnetic sensor configured to detect when the magnet is magnetically coupled to an external accessory separate from the power transmitting device and when the magnet is magnetically coupled to both the external accessory and the power transmitting device. The magnetic sensor can differentiate between when the magnet is only magnetically coupled to the external accessory and when the magnet is magnetically coupled to both the external accessory and the power transmitting device. The power transmitting device can include a first near-field communications tag configured to transmit information about the power transmitting device to the near-field communications reader. The external accessory comprises a second near-field communications tag configured to transmit information about the external accessory to the near-field communications reader. The near-field communications reader can perform anti-collision operations when multiple tags are detected. When collisions are detected, the near-field communications reader may communicate with only one of the tags while the other tag is halted, before halting the tag that was just read and then reading the tag that was first halted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an illustrative wireless power system in accordance with some embodiments. 
         FIG. 2  is a circuit schematic of illustrative wireless power transmitting and receiving circuitry in accordance with some embodiments. 
         FIG. 3  is a cross-sectional side view of an illustrative wireless charging system in accordance with some embodiments. 
         FIG. 4  is a cross-sectional side view of an illustrative wireless charging system in accordance with some embodiments. 
         FIG. 5  is a diagram of an accessory configured to mate with a portable electronic device in accordance with some embodiments. 
         FIG. 6  is a top view of a portable electronic device in accordance with some embodiments. 
         FIG. 7  is a flow chart of illustrative steps for using near-field communications circuitry to communicate between a portable electronic device and one or more accessories in accordance with some embodiments. 
         FIG. 8  is a timing diagram illustrating how a magnetometer can be used to detect the presence of one or more accessories in accordance with an embodiment. 
         FIG. 9  is a flow chart for performing near-field communications in accordance with some embodiments. 
         FIG. 10  is a flow chart for performing near-field communications in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     A wireless power system may include one or more electronic devices that transmit wireless power, one or more electronic devices that receive wireless power, and one or more electronic devices that both transmit and receive wireless power. The wireless power transmitting device may be a wireless charging mat or wireless charging puck, as examples. The wireless power receiving device may be a portable device such as a wristwatch, cellular telephone, tablet computer, laptop computer, or other electronic equipment, as examples. The wireless power transmitting and receiving device may be an electronic device case (e.g., a removable case for a cellular telephone) or other type of electronic device. The wireless power transmitting device may wirelessly transmit power to a wireless power receiving device. The wireless power receiving device uses power from the wireless power transmitting device for powering the device and for charging an internal battery. 
     Wireless power is transmitted from the wireless power transmitting device to the wireless power receiving device using one or more wireless power transmitting coils. The wireless power receiving device has one or more wireless power receiving coils coupled to rectifier circuitry that converts received wireless power signals into direct-current power. 
     An illustrative wireless power system (wireless charging system or wireless power transfer system) is shown in  FIG. 1 . Devices in wireless power system  8  may include wireless power transmitting devices such as wireless power transmitting device  12 . Devices in wireless power system  8  may include wireless power receiving devices such as wireless power receiving device  24 . Devices in wireless power system  8  may include electronic devices capable of both transmitting and receiving wireless power such as wireless power transmitting and receiving device  18 . 
     Exemplary wireless power transmitting device  12  includes control circuitry  16 . Exemplary wireless power receiving device  24  includes control circuitry  30 . Exemplary wireless power transmitting and receiving device  18  includes control circuitry  78 . These control circuitries may include processing circuitry associated with microprocessors, power management units, baseband processors, digital signal processors, microcontrollers, and/or application-specific integrated circuits with processing circuits. These processing circuitry implements desired control and communications features in devices  12 ,  18 , and  24 . For example, the processing circuitry may be used in selecting coils, determining power transmission levels, processing sensor data and other data to detect foreign objects and perform other tasks, processing user input, handling negotiations/handshakes between devices  12 ,  18 , and  24 , sending and receiving in-band and out-of-band data, making measurements, and otherwise controlling the operation of respective wireless transmitters and receivers in system  8 . 
     Control circuitry in system  8  may be configured to perform operations in system  8  using hardware (e.g., dedicated hardware or circuitry), firmware and/or software. Software code for performing operations in system  8  is stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media) in control circuitry  8 . The software code may sometimes be referred to as software, data, program instructions, instructions, or code. The non-transitory computer readable storage media may include non-volatile memory such as non-volatile random-access memory (NVRAM), one or more hard drives (e.g., magnetic drives or solid state drives), one or more removable flash drives or other removable media, or the like. Software stored on the non-transitory computer readable storage media may be executed on the processing circuitry of control circuitry  16 ,  30 , and/or  78 . The processing circuitry may include application-specific integrated circuits with processing circuitry, one or more microprocessors, a central processing unit (CPU) or other processing circuitry. 
     Power transmitting device  12  may be a stand-alone power adapter (e.g., a wireless charging mat or charging puck that includes power adapter circuitry), may be a wireless charging mat or puck that is coupled to a power adapter or other equipment by a cable, may be a portable device, may be equipment that has been incorporated into furniture, a vehicle, or other system, may be a removable battery case, or may be other wireless power transfer equipment. Illustrative configurations in which wireless power transmitting device  12  is a wireless charging mat or puck are sometimes described herein as an example. 
     Power receiving device  24  may be a portable electronic device such as a wristwatch, a cellular telephone, a laptop computer, a tablet computer, an accessory such as an earbud or an electronic pencil (e.g., a stylus), a head-mounted display, or other electronic equipment. Power transmitting device  12  may be coupled to a wall outlet (e.g., an alternating current power source), may have a battery  32  for supplying power, and/or may have another source of power. Power transmitting device  12  may have an alternating-current (AC) to direct-current (DC) power converter such as AC-DC power converter  14  for converting AC power from a wall outlet or other power source into DC power. DC power may be used to power control circuitry  16 . During operation, a controller in control circuitry  16  uses power transmitting circuitry  52  to transmit wireless power to power receiving circuitry  54  of device  24 . 
     Power transmitting circuitry  52  may have switching circuitry (e.g., inverter circuitry  61  formed from transistors) that is turned on and off based on control signals provided by control circuitry  16  to create AC current signals through one or more wireless power transmitting coils such as wireless power transmitting coil(s)  36 . These coil drive signals cause coil(s)  36  to transmit wireless power. Coils  36  may be arranged in a planar coil array or may be arranged to form a cluster of coils. In some embodiments, device  12  (e.g., a charging mat, puck, etc.) may have only a single coil. In other embodiments, a wireless charging device may have multiple coils. 
     As the AC currents pass through one or more coils  36 , alternating-current electromagnetic (e.g., magnetic) fields (wireless power signals  44 ) are produced that are received by one or more corresponding receiver coils such as coil(s)  48  in power receiving device  24 . Rectifier circuitry such as rectifier circuitry  50  converts received AC signals (received alternating-current signals associated with electromagnetic signals  44 ) from one or more coils  48  into DC voltage signals for powering device  24 . The DC voltage produced by rectifier circuitry  50  (sometime referred to as rectifier output voltage Vrect) can be used in charging a battery such as battery  58  and can be used in powering other components in device  24 . 
     Device  12 , device  18 , and/or device  24  may communicate wirelessly using in-band or out-of-band communications. Device  12  may, for example, have wireless transceiver circuitry  40  that wirelessly transmits out-of-band signals (e.g., to device  18  or device  24 ) using an antenna. Wireless transceiver circuitry  40  may be used to wirelessly receive out-of-band signals from device  18  or  24  using the antenna. Device  24  may have wireless transceiver circuitry  46  that transmits out-of-band signals. Receiver circuitry in wireless transceiver  46  may use an antenna to receive out-of-band signals. Device  18  may have wireless transceiver circuitry  80  that transmits out-of-band signals. Receiver circuitry in wireless transceiver  80  may use an antenna to receive out-of-band signals. 
     In illustrative embodiments, device  12  includes near-field communications (NFC) circuitry  53  for transmitting information to corresponding NFC circuitry  55  in device  24 . Device  18  may also include NFC circuitry  85  for receiving information from device  12  and/or transmitting information to device  24 . Data conveyed using these NFC components may also be considered out-of-band signals and may be radiated using a separate NFC antenna within each device. Each NFC circuitry may include circuitry that operates as an NFC reader (sometimes referred to as a proximity coupling device or PCD) and/or as an NFC tag (sometimes referred to as a proximity inductive coupling card or PICC). An NFC tag may be active or passive. An active NFC tag can actively transmit a signal to the NFC reader, whereas a passive NFC tag modulates the carrier waveform transmitted by the NFC reader. Exemplary NFC communications operate at 13.56 MHz. In some embodiments, NFC communications may employ millimeter/centimeter wave technologies at 10 GHz or above (to about 300 GHz). 
     Wireless transceiver circuitry  40 ,  46 , and  80  may also be used for in-band transmissions between devices  12 ,  24 , and  18  using coils  36 ,  48 , and  90 . Frequency-shift keying (FSK) and/or amplitude-shift keying (ASK) may be used to convey in-band data between devices  12 ,  18 , and  24 . Power may be conveyed wirelessly during these FSK and ASK transmissions. It is desirable for power transmitting device  12 , power transmitting and receiving device  18 , and power receiving device  24  to be able to communicate information such as received power, battery states of charge, and so forth, to control wireless power transfer. Control circuitry  16  has external object measurement circuitry  41  that may be used to detect external objects on the charging surface of the housing of device  12  (e.g., on the top of a charging mat or, if desired, to detect objects adjacent to the coupling surface of a charging puck). The housing of device  12  may have polymer walls, walls of other dielectric, and/or other housing wall structures that enclose coil(s)  36  and other circuitry of device  12 . The charging surface may be formed by a planer outer surface of the upper housing wall of device  12  or may have other shapes (e.g., concave or convex shapes, etc.). In arrangements in which device  12  forms a charging puck, the charging puck may have a surface shape that mates with the shape of device  24 . A puck or other device  12  may, if desired, have magnets that removably attach device  12  to device  24 , so that coil  48  aligns with coil  36  during wireless charging). 
     Circuitry  41  can detect foreign objects such as coils, paper clips, and other metallic objects and can detect the presence of wireless power receiving devices  24  (e.g., circuitry  41  can detect the presence of one or more coils  48  and/or magnetic core material associated with coils  48 ). During object detection and characterization operations, external object (foreign object) measurement circuitry  41  can be used to make measurements on coil(s)  36  such as Q-factor measurements, resonant frequency measurements, and/or inductance measurements that can indicate whether coil  48  is present and/or whether foreign objects such as coins or paperclips are present. Measurement circuitry can also be used to make sensor measurements using a capacitive sensor, can be used to make temperature measurements, and/or can otherwise be used in gathering information indicative of whether a foreign object or other external object (e.g., device  18  or  24 ) is present on device  12 . 
     Power transmitting and receiving device  18  may be a battery case or a battery pack that is coupled to a power adapter or other equipment by a cable, may be equipment that has been incorporated into furniture, a vehicle, or other system, may be a removable battery case, may be a portable electronic device such as a wrist watch, a cellular telephone, a laptop computer, a tablet computer, an accessory such as an earbud, or other electronic equipment. Power transmitting and receiving device  18  is capable of both transmitting and receiving wireless power. Power transmitting and receiving device  18  therefore may include power transmitting components, similar to power transmitting device  12 . Power transmitting and receiving device  18  may also include power receiving components, similar to power receiving device  24 . 
     Power transmitting and receiving device  18  may have an alternating-current (AC) to direct-current (DC) power converter such as AC-DC power converter  96  for converting AC power from a wall outlet or other power source into DC power. DC power may be used to power control circuitry  78 . Control circuitry  78  includes wireless transceiver circuitry  80  for in-band communications (using coils  90 ) and out-of-band communications (using an antenna). Control circuitry  78  may also optionally include measurement circuitry  82  (e.g., measurement circuitry of the type described in connection with measurement circuitry  41 ). 
     Wireless power circuitry  84  in device  18  may include both an inverter  86  and a rectifier  88 . Inverter circuitry  86  (e.g., formed from transistors) may be turned on and off based on control signals provided by control circuitry  78  to create AC current signals through one or more coils such as coil(s)  90 . These coil drive signals cause coil(s)  90  to transmit wireless power. Coils  90  may be arranged in a planar coil array or may be arranged to form a cluster of coils. In some arrangements, device  18  may have only a single coil. In other arrangements, device  18  may have multiple coils (e.g., two or more coils, 5-10 coils, at least 10 coils, 10-30 coils, fewer than 35 coils, fewer than 25 coils, or other suitable number of coils). 
     As the AC currents pass through one or more coils  90 , alternating-current electromagnetic (e.g., magnetic) fields (wireless power signals  44 ) are produced that are received by one or more corresponding receiver coils such as coil(s)  48  in power receiving device  24 . In other words, one or more of coils  90  may be inductively coupled to one or more of coils  48 . 
     Power transmitting and receiving device  18  may also receive wireless power (e.g., from power transmitting device  12 ). Coil(s)  90  may receive alternating-current electromagnetic fields from transmitting coils  36 , resulting in corresponding alternating-current currents in coil(s)  90 . Rectifier circuitry such as rectifier circuitry  88 , which contains rectifying components such as synchronous rectification metal-oxide-semiconductor transistors arranged in a bridge network, converts received AC signals (received alternating-current signals associated with electromagnetic signals  44 ) from one or more coils  90  into DC voltage signals for powering device  18 . The DC voltage produced by rectifier circuitry  88  can be used in charging a battery such as battery  94  and can be used in powering other components in device  18 . 
     In some applications, power transmitting and receiving device  18  only transmits wireless power (e.g., using inverter  86  and coil(s)  90 ). In some applications, power transmitting and receiving device  18  only receives wireless power (e.g., using rectifier  88  and coil(s)  90 ). In some applications, power transmitting and receiving device simultaneously receives and transmits wireless power. When simultaneously receiving and transmitting wireless power, device  18  may optionally perform both the power transmitting and power receiving operations associated with inverter  86  and rectifier  88  (e.g., device  18  uses the rectifier to charge the battery and operate the device and independently uses the inverter to transmit a desired amount of power). Alternatively, device  18  may relay or pass through received wireless power signals without rectifying the power. Device  18  may include only one coil that is used for both wireless power transmission and wireless power reception. Alternatively, device  18  may have at least one dedicated wireless power transmitting coil and at least one dedicated wireless power receiving coil. Device  18  may have multiple coils that are all used for both wireless power transmission and wireless power reception. Different coils in device  18  may optionally be shorted together in different modes of operation. 
       FIG. 2  is a circuit diagram of illustrative wireless charging circuitry useful in implementing system  8 . Wireless charging circuitry of a power transmitting device  12  and a power receiving device  24  is shown. However, it should be understood that device  18  may have the corresponding components for both power transmission and power reception and may be used in place of either device  12  and/or device  24  if desired. As shown in  FIG. 2 , circuitry  52  may include inverter circuitry such as one or more inverters  61  or other drive circuitry that produces wireless power signals that are transmitted through an output circuit that includes one or more coils  36  and capacitors such as capacitor  71 . In some embodiments, device  12  may include multiple individually controlled inverters  61 , each of which supplies drive signals to a respective coil  36 . In other embodiments, an inverter  61  is shared between multiple coils  36  using switching circuitry. 
     During operation, control signals for inverter(s)  61  are provided by control circuitry  16  at control input  74 . A single inverter  61  and single coil  36  is shown in the example of  FIG. 2 , but multiple inverters  61  and multiple coils  36  may be used, if desired. In a multiple coil configuration, switching circuitry (e.g., multiplexer circuitry) can be used to couple a single inverter  61  to multiple coils  36  and/or each coil  36  may be coupled to a respective inverter  61 . During wireless power transmission operations, transistors in one or more selected inverters  61  are driven by AC control signals from control circuitry  16 . The relative phase between the inverters can be adjusted dynamically. For example, a pair of inverters  61  may produce output signals in phase or out of phase (e.g., 180 degrees out of phase). 
     The application of drive signals using inverter(s)  61  (e.g., transistors or other switches in circuitry  52 ) causes the output circuits formed from selected coils  36  and capacitors  71  to produce alternating-current electromagnetic fields (signals  44 ) that are received by wireless power receiving circuitry  54  using a wireless power receiving circuit formed from one or more coils  48  and one or more capacitors  72  in device  24 . 
     If desired, the relative phase between driven coils  36  (e.g., the phase of one of coils  36  that is being driven relative to another adjacent one of coils  36  that is being driven) may be adjusted by control circuitry  16  to help enhance wireless power transfer between device  12  and device  24 . Rectifier circuitry  50  is coupled to one or more coils  48  (e.g., a pair of coils) and converts received power from AC to DC and supplies a corresponding direct current output voltage Vrect across rectifier output terminals  76  for powering load circuitry in device  24  (e.g., for charging battery  58 , for powering a display and/or other input-output devices  56 , and/or for powering other components). A single coil  48  or multiple coils  48  may be included in device  24 . In an illustrative configuration, device  24  may be a wristwatch or other portable device with at least two coils  48 . These two (or more) coils  48  may be used together when receiving wireless power. Other configurations may be used, if desired. 
     As previously mentioned, in-band transmissions using coils  36  and  48  may be used to convey (e.g., transmit and receive) information between devices  12  and  24 . With one illustrative configuration, frequency-shift keying (FSK) is used to transmit in-band data from device  12  to device  24  and amplitude-shift keying (ASK) is used to transmit in-band data from device  24  to device  12 . In other words, a device transmitting wireless power may use FSK to transmit in-band data to a device receiving wireless power (regardless of whether either device is a dedicated power transmitting/receiving device  12 / 24  or a power receiving and transmitting device  18 ). A device receiving wireless power may use ASK to transmit in-band data to a device transmitting wireless power (regardless of whether either device is a dedicated power transmitting/receiving device  12 / 24  or a power receiving and transmitting device  18 ). 
     Power may be conveyed wirelessly from device  12  to device  24  during these FSK and ASK transmissions. While power transmitting circuitry  52  is driving AC signals into one or more of coils  36  to produce signals  44  at the power transmission frequency, wireless transceiver circuitry  40  may use FSK modulation to modulate the power transmission frequency of the driving AC signals and thereby modulate the frequency of signals  44 . In device  24 , coil  48  is used to receive signals  44 . Power receiving circuitry  54  uses the received signals on coil  48  and rectifier  50  to produce DC power. At the same time, wireless transceiver circuitry  46  monitors the frequency of the AC signal passing through coil(s)  48  and uses FSK demodulation to extract the transmitted in-band data from signals  44 . This approach allows FSK data (e.g., FSK data packets) to be transmitted in-band from device  12  to device  24  with coils  36  and  48  while power is simultaneously being wirelessly conveyed from device  12  to device  24  using coils  36  and  48 . 
     In-band communications between device  24  and device  12  may use ASK modulation and demodulation techniques. Wireless transceiver circuitry  46  transmits in-band data to device  12  by using a switch (e.g., one or more transistors in transceiver  46  that are coupled coil  48 ) to modulate the impedance of power receiving circuitry  54  (e.g., coil  48 ). This, in turn, modulates the amplitude of signal  44  and the amplitude of the AC signal passing through coil(s)  36 . Wireless transceiver circuitry  40  monitors the amplitude of the AC signal passing through coil(s)  36  and, using ASK demodulation, extracts the transmitted in-band data from these signals that was transmitted by wireless transceiver circuitry  46 . The use of ASK communications allows ASK data bits (e.g., ASK data packets) to be transmitted in-band from device  24  to device  12  with coils  48  and  36  while power is simultaneously being wirelessly conveyed from device  12  to device  24  using coils  36  and  48 . 
     The example of FSK modulation being used to convey in-band data from power transmitting device  12  to power receiving device  24  and ASK modulation being used to convey in-band data from power receiving device  24  to power transmitting device  12  is merely illustrative. In general, any desired communication techniques may be used to convey information from power transmitting device  12  to power receiving device  24  and from power receiving device  24  to power transmitting device  12 . In general, wireless power may simultaneously be conveyed between devices during in-band communications (using ASK or FSK). 
     The power transmission frequency used for transmission of wireless power may be, for example, a predetermined frequency of about 125 kHz, at least 80 kHz, at least 100 kHz, between 100 kHz and 205 kHz, less than 500 kHz, less than 300 kHz. or other suitable wireless power frequency. In some configurations, the power transmission frequency may be negotiated in communications between devices  12  and  24 . In other configurations, the power transmission frequency may be fixed. 
     It has been described that power may be simultaneously conveyed between devices while using in-band communication for data transmission between the devices. In other words, in some examples in-band communications may rely on modulation of the power transmission signal (e.g., modulating the power transmission frequency or modulating amplitude of a signal at the power transmission frequency). However, other communication techniques may be used that do not rely on modulation of the power transmission signals. For example, signals (sometimes referred to as in-band signals) may be conveyed between coils in the system at a frequency that is different than the power transmission frequency. Signals (at the same frequency or a different frequency than the power transmission frequency) that are conveyed using the coils (e.g., coils  36 ,  48 , and  90  in  FIG. 1 ) may be considered in-band signals. 
       FIG. 3  is a cross-sectional side view of a portable electronic device  100  (e.g., a wrist watch, a cellular telephone, a laptop computer, a tablet computer, or other electronic equipment) on the surface of wireless charging mat (or puck)  102 . Device  100  may be a wireless power receiving device (e.g., device  24  in  FIG. 1 ) or may be a wireless power transmitting and receiving device (e.g., device  18  in  FIG. 1 ). Device  102  may be a wireless power transmitting device (e.g., device  12  in  FIG. 1 ). 
     As shown in  FIG. 3 , device  102  may include a wireless charging coil  120  (e.g., a wireless power transmitting coil), an NFC antenna structure  122 , and magnetic alignment structure  124 . Wireless charging coil  120  may be wound from a single-strand conductor, a multiple strand conductor having multiple wires connected in parallel, braided wire, Litz wire, a conductive ink or conductive trace such as multilayer tracks on a printed circuit board, or other conductive elements suitable for forming coils. Coil  120  may represent a single coil or multiple coils (e.g., a planar coil array, a cluster of coils, or any suitable number of overlapping and/or non-overlapping coil structures). NFC antenna  122  may be formed around wireless charging coil  120  (e.g., NFC antenna  122  may be routed along the inner or outer periphery of coil  120  and may at least partially or completely surround coil  120 ). In one suitable arrangement, wireless charging coil  120  and NFC antenna  122  may form concentric loop structures. Magnetic alignment structure  124  may be formed around NFC antenna  122  (e.g., alignment structure  124  may be formed along the periphery of antenna  122  and may at least partially or completely surround antenna  122 ). In some configurations. NFC antenna  122  and magnetic alignment structure  124  may form concentric loops. 
     Device  100  may include a wireless charging coil  110  (e.g., a wireless power receiving coil), an NFC antenna structure  112 , magnetic alignment structure  114 , and a magnetic sensor such as a magnetometer  116 . Wireless power receiving coil  110  may be configured to received wireless power signals from wireless power transmitting coil  120 . For instance, wireless power transmitting coil  120  may be driven using inverter  61  in device  12  of  FIG. 2 , whereas wireless power receiving coil  110  may be used to drive rectifier  50  in device  24  of  FIG. 2 . Wireless charging coil  110  may be wound from a single-strand conductor, a multiple strand conductor having multiple wires connected in parallel, braided wire. Litz wire, a conductive ink or conductive trace such as multilayer tracks on a printed circuit board, or other conductive elements suitable for forming coils. 
     NFC antenna  112  may be formed around wireless charging coil  110  (e.g., NFC antenna  112  may be routed along the periphery of coil  110  and may at least partially or completely surround coil  110 ). In one suitable arrangement, wireless charging coil  110  and NFC antenna  112  may form concentric loop structures. NFC antenna structure  112  in device  100  should have the same or similar structure and footprint as NFC antenna structure  122  of device  102  to ensure optimal coupling between the two antenna structures. 
     Magnetic alignment structure  114  may be formed around NFC antenna  112  (e.g., alignment structure  114  may be formed along the periphery of antenna  112  and may at least partially or completely surround antenna  112 ). In some configurations. NFC antenna  112  and magnetic alignment structure  114  may form concentric loops. Magnetic alignment structure  114  in device  100  may magnetically couple with a corresponding magnetic alignment structure  124  in device  102  (e.g., magnets  114  may magnetically attract magnets  124  and vice versa). When magnetic alignment structure  114  in device  100  is coupled to magnetic alignment structure  124  in device  102 , the power transmitting coil  120  may be aligned with the power receiving coil  110  (e.g., so that coils  110  and  120  are in proper spatial alignment for optimal wireless power transfer). The magnetic alignment structures thus promote proper alignment of the wireless power receiving coil with respect to the wireless power transmitting coil. Magnetic alignment structures  114  and  124  may be permanent magnets (e.g., formed from hard magnetic materials that retain their magnetism over time). 
     In accordance with an embodiment, devices  100  and  102  may communicate prior to wireless power transfer operations. These communications include communications to establish wireless power delivery. In some embodiments, these communications include negotiations that support features such as issuing a charging notification, chime, alert, or otherwise conveying the nature of the device  102 , such that the user is informed as to the operation of their device. As an example, device  100  may receive information indicating that it has been placed on a wireless charging mat. In response, device  100  may present a wireless charging mat icon on its display to indicate that its battery is now charging from a wireless charging mat. 
     Communications may also include NFC-based communications. The NFC reader in device  100  may be triggered or activated using a magnetic sensor such as magnetometer  116 . Magnetometer  116  is, for example, a Hall effect sensor, a rotating coil magnetometer, a magneto-resistive sensor, a fluxgate sensor, a microelectromechanical systems magnetic field sensor, or other types of magnetic sensors. In some embodiments, magnetometer  116  is multiple-axis magnetic sensor configured to decipher the polarity of attachment. When multi-axis magnetic sensor  116  detects that accessory  104  is coupled in a first, correct, orientation with device  100 , further processing such as NFC communications are triggered. When multi-axis magnetic sensor  116  detects a magnetic reading that is unrecognized or indicates that an accessory has been coupled in a second, incorrect orientation (e.g., upside down), device  100  forgoes operations such as indicating the attachment via user notification. Magnetic sensor  116  may monitor or measure the magnetic field at magnetic alignment structure  114 . When device  100  is not attached to device  102 , magnetic sensor  116  may measure a first amount of magnetism that is below a threshold level. When device  100  is attached to device  102  (e.g., when structures  114  and  124  are aligned), magnetic sensor  116  may detect a second amount of magnetism that exceeds the threshold level. When the output of sensor  116  exceeds the threshold, magnetic sensor  116  may send a wake-up signal to the NFC reader in device  100 . Operated in this way, magnetometer  116  may be used to trigger or initiate the NFC communications between devices  100  and  102 . 
     In some embodiments device  100  presents an indication regarding the attachment of an accessory. For example, when a wireless power transmitter is inductively coupled with device  100 , device  100  chimes audibly, and displays a battery charging icon and chines. In some embodiments, device  100  presents an indication regarding an attribute of an attached accessory. For example, when device  100  is coupled with a purple colored protective cover, device  100  presents an indication that it is coupled with a purple cover. In some embodiments, device  100  presents an indication regarding a functionality of an attached accessory. For example, when device  100  is coupled with a battery-powered protective cover, device  100  presents an indication that it is coupled with a purple cover, that the cover has a battery that is charged, and/or that it is receiving power from the battery-powered case. In some embodiments, device  100  presents an indication regarding an identity of an attached accessory. For example, when device  100  is coupled with a dock, device  100  presents an indication that is coupled with an unknown device and seeks permission to proceed further. Responsive to user permission to proceed, device  100  may indicate that the dock is named “Kitchen” and is associated with a number of food recipes that may be presented via device  100 . 
       FIG. 4  illustrates another suitable configuration in which portable electronic device  100  is inserted within battery case  104 . Device  102  may be a wireless power transmitting device such as a wireless charging mat or puck with a charging surface. Device  104  has a housing such as housing  138  with a recess R and/or other structures configured to receive device  100 . In this way, a user may removably attach device  100  to device  104  so that devices  100  and  104  may be used together as a portable unit. When it is desired to receive wireless power from device  102 , devices  104  and  100  may be placed together on the charging surface of device  102 . Device  104  optionally includes NFC antenna  132  and magnetic alignment structure  134 . NFC antenna  132  allows device  104  to communicate with devices  100  and/or  102 . Magnetic alignment structure  143  promotes spatial alignment and inductive coupling of device  104  with devices  100  and/or  102 . 
     In some embodiments, devices  100  and  104  communicate using NFC antennas  112  and  132  respectively. In some examples, NFC communication occurs during wireless power handshake operations, by temporarily halting the power handshake/negotiation process to perform the NFC communications. In some examples, NFC communication occurs during wireless power transfer operations, by temporality halting the active wireless power transfer to perform the NFC communications. The NFC reader in device  100  may be triggered or activated using magnetic sensor  116 , which monitors or measures the magnetic field at magnetic alignment structure  114 . When device  100  is not attached to device  104 , magnetic sensor  116  may detect a first amount of magnetism that is below a given threshold. When device  100  is attached to device  104  (e.g., when structures  114  and  134  are aligned), magnetic sensor  116  may measure a second amount of magnetism that exceeds the given threshold. When the output of sensor  116  exceeds the given threshold, magnetic sensor  116  may signal the NFC reader in device  100 . Operated in this way, magnetometer  116  may be used to trigger or initiate the NFC communications between devices  100  and  104 . 
     In the example of  FIG. 4  in which portable electronic device  100  is attached to two different accessory devices, the audio, haptic, and/or visual affordance output by device  100  may be triggered upon attachment of each accessory or both accessories at the same time. For instance, device  100  may first be installed within device  104 . When device  100  is placed within recess R in housing  138  of device  104 , magnetic alignment structures  114  and  134  may spatially align devices  100  and  104  so that transmitting coil  130  is aligned with receiving coil  110 . When magnetic alignment structures  114  and  134  are aligned, magnetic sensor  116  may detect the presence of device  104  and will activate NFC antenna  112  of the reader in device  100  to generate a magnetic field. The magnetic field generated by antenna  112  may induce a corresponding current to flow through antenna  132  of the NFC tag in device  104 , thereby activating the NFC tag. 
       FIG. 5  is a side view of another accessory such as device  108  that may be attached to device  100 . Device  108  may be a stand or dock for holding or otherwise supporting device  100  in an upright or semi-upright position. In some embodiments device  108  does not include a wireless charging coil. If desired, however, device  108  may be provided with one or more wireless charging coils. Device  106  includes NFC antenna  152  and magnetic alignment structure  154 . Magnetic alignment structure  154  may be formed around NFC antenna  152  (e.g., magnetic alignment structure  154  may be routed along the periphery of antenna  152  and may at least partially or completely surround antenna  152 ). In one suitable arrangement, NFC antenna  152  and magnetic alignment structure  154  may form concentric loop structures. NFC antenna structure  152  in device  108  should have the same or similar structure and footprint as NFC antenna structure  112  of device  100  to ensure optimal coupling between the two antenna structures. NFC antenna  152  may be part of an NFC tag within device  108 , which may be used to transmit device-specific information to NFC antenna  112  within device  100 . 
     Magnetic alignment structure  154  in device  108  may magnetically couple with a corresponding magnetic alignment structure  114  in device  100  (e.g., magnets  114  may magnetically attract magnets  154  and vice versa). When magnetic alignment structure  154  in device  108  is coupled to magnetic alignment structure  114  in device  100 , NFC tag antenna  152  may be aligned with the corresponding NFC reader antenna  112  in device  100  to carry out NFC communication. 
     In accordance with an embodiment, device  108  may be configured to transmit information to device  100  using NFC upon attaching to device  100  but prior to wireless power transfer operations so that device  100  may issue a notification, chime, alert, or otherwise display some confirmatory information about the coupling of device  108  to the user. As an example, device  100  may receive information from device  108  indicating that it has been inserted into a docking accessory. In response, device  100  may present a dock icon on its display to indicate that it is now attached to a dock accessory. In another example, device  100  may receive information from device  108  indicating that it has been attached to a dock named “kitchen”. Device may present a kitchen icon on its display and/or may provide a default user interface screen that is associated with the dock. 
       FIG. 6  is a top view of a wireless charging coil, NFC antenna, and magnetic alignment structures in an illustrative portable electronic device  100 . As shown, device  100  includes one or more coils  110 . Coil(s)  110  may be wrapped around or overlapping with a magnetic core. Coil  110  may be ring-shaped (sometimes referred to as an annular coil or circular coil), may have a central opening  164  with one or more magnetic cores optionally formed in the central opening. A ring-shaped NFC antenna  112  may laterally surround coil  110 . Antenna structure  112  may sometimes be described as annular or circular. A ring-shaped magnetic alignment structure  114  may laterally surround NFC antenna  112 . Magnetic alignment structure  114  may sometimes be described as annular or circular. In  FIG. 6 , coil  110 , antenna  112 , and magnetic alignment structure  114  are concentric (e.g., each structure  110 ,  112 , and  114  may have a center coinciding at point C). Antenna  112  runs along a peripheral edge of wireless charging coil  110 . Magnetic alignment structure  114  runs along a peripheral edge of NFC antenna  112 . Concentric point C may bisect the horizontal width dimension across the housing of device  100  (as shown by bisecting line  160 ) and may also bisect the vertical length dimension across the housing of device  110  (as shown by bisecting line  162 ). 
     If desired, device  100  may include two or more wireless charging coils, NFC antenna  112  may be formed from two or more discrete antenna members arranged in a circular (annular) pattern, and magnetic alignment structure  114  may be formed from two or more discrete magnetic alignment members arranged in a circular (annular) pattern. Each of the discrete NFC antenna members and/or magnetic alignment members may have an arcuate arrangement. In other suitable embodiments, structures  110 ,  112 , and  114  may be oval, triangular, rectangular, pentagonal, hexagonal, octagonal, or have another polygonal footprint. 
     Magnetic sensor  116  may be placed in close proximity to magnetic alignment structure  114  to effectively measure the magnetism of alignment structure  114 . For example, magnetic sensor  116  and alignment structure  114  may be separated by a distance less than 1 cm, less than 0.5 cm, less than 1 mm, less than 0.5 mm, less than 0.1 mm, between 0.1 mm and 1 cm, between 0.1 mm and 1 mm, between 0.1 cm and 1 cm, between 0.1 cm and 0.5 cm, between 0.1 mm and 0.5 mm, or by other suitable distance. 
     Various arrangements of wireless charging coil (such as coil  110 ) NFC antenna (such as antenna  112 ), magnet (such as magnet  114 ) are possible consistent with the techniques described herein. In some embodiments, NFC antenna  112  is disposed along an outer periphery of magnet  114 , and wireless charging coil  110  is disposed along the inner periphery of magnet  114 . The positions of NFC antenna  112  and wireless charging coil  110  can be reversed. In some embodiments, both wireless charging coil  110  and NFC antenna  112  reside inside the inner periphery of magnet  114 . The positions of wireless charging coil  110  and NFC antenna  112  can be reversed. In some embodiments, both wireless charging coil  110  and NFC antenna  112  reside outside the outer periphery of magnet  114 . The positions of wireless charging coil  110  and NFC antenna  112  can be reversed. These examples are illustrative. 
       FIG. 7  is a flow chart of exemplary processes involved in attaching a portable electronic device to one or more accessory devices in accordance with embodiments described herein. At block  200 , a device such as portable electronic device  100  ( FIG. 1 ) is attached to an accessory device (e.g., power transmitting device  12  of  FIG. 1 , power transmitting and receiving device  18  of  FIG. 1 , device  102  of  FIG. 3 , device  104  of  FIG. 4 , device  108  of  FIG. 5 ,) via magnetic alignment structures (e.g., structures  114  and  124  of  FIG. 3 , structures  114  and  134  of  FIG. 4 ). 
     At block  202 , magnetic sensor  116  of portable electronic device  100  detects the presence of the accessory device that has just been attached to device  100 . In response to magnetic sensor  116  detecting appropriate attachment of an accessory device, at block  204  ( FIG. 8 ), NFC components in device  100  and the attached accessory communicate with one another. In some embodiments, NFC communications include verifying the authenticity of the attached devices. In some embodiments, NFC communications include encryption. In some embodiments. NFC communications include transfer of information regarding device  100  and/or the accessory. In some examples, device  100  obtains information indicative of the type of accessory that has been attached, such as whether the accessory is a dock. In some examples, device  100  obtains information indicating functionalities provided by the attached accessory, such as whether the accessory provides power. 
     At block  206 , device  100  presents information about the attached accessory on its display using the information received during block  204 . For example, device  100  may display a wireless charging puck graphic or a phone case graphic, responsive to determining that a wireless charging puck or a phone case, respectively, has been attached to device  100 . Device  100  may also display a charging icon if device  100  is receiving power, such as wireless power signals, from the attached accessory. A functionality of device  100  may be made available or made unavailable based on the information received from the attached accessory. That is, certain applications may be enabled when device  100  is attached to a certain type of accessory. Also, certain applications may be disabled when device  100  is attached to a certain type of accessory. Device  100  may also alter its menu of available functions, such as the widget and application icons, based on information received from an attached accessory. 
     As indicated by branch  208 , device  100  may repeat blocks  202 - 206  as additional devices are attached. For example, device  100  may attach to wireless charging puck through an intervening protective case. 
     When device  100  is detached from an accessory, magnetic sensor  116  may sense the removal of the accessory at block  210 , and present information about the detachment in block  212 . The presentation of information includes one or more of an audio, haptic, and visual indications. When device  100  is detached from an accessory, device  100  may also note the location of detachment, and later present lost-and-found information. For example, the detaching of device  100  from a car mount provides a meaningful parking location for the car, and the parking location could be presented in a map of the local area. 
       FIG. 8  is a timing diagram illustrating how magnetic sensor  116  of device  100  ( FIG. 1 ) may detect attachment and detachment of accessories to device  100 , such as during blocks  202  and  210  of  FIG. 7 , respectively. Sensor  116  may be configured to gather measurements at a predetermined time interval. For example, sensor  116  may gather one or more readings once per second (with a frequency of 1 Hz), twice per second (with a frequency of 2 Hz), three times per second (with a frequency of 3 Hz), more than three times per second (with a frequency greater than 3 Hz), 3-10 times per second, less than once per second, at most once every two seconds, at most once every three seconds, or at other suitable periodicity. 
       FIG. 8  illustrates exemplary measurements  312  at times t 1 , t 2 , and t 3 , provided by sensor  116 . These magnetic measurements lay within a first range of values  302 . Magnetic sensor outputs within range  302  may be indicative that no external accessory or magnetic component is presently attached to device  100 . At time t 4 , a first accessory (e.g., a battery case) may be installed on device  100 . During the attachment of device  100  and the battery case, the magnetic alignment structure within the battery case may be magnetically coupled to and aligned with magnetic alignment structure  114  of device  100 . Sensor  116  may detect the approach and proximity of the battery case and output second magnetic measurements  314  lying within a second range of values  304 . Magnetic sensor readings falling within range  304  may be indicative that one external accessory is presently attached to device  100 . Ranges  302  and  304  may be separated by a trigger gap  308  to ensure that there is adequate margin to help differentiate between the first scenario where no accessory is present and the second scenario where one accessory is attached. 
     At time t 9 , device  100  and the battery case, as one movable unit, may be placed on a second accessory (e.g., a wireless charging mat or puck). When the battery case is placed on the charging surface of the second accessory, the magnetic alignment structure within the battery case may be magnetically coupled to and aligned with the magnetic alignment structure of the second accessory and with magnetic alignment structure  114  of device  100 . As a result, sensor  116  within device  100  may output second magnetic measurements  316  lying within a third range of values  306 . Magnetic sensor readings falling within range  306  may be indicative that two external accessories are presently attached to device  100  (i.e., device  100  is presently stacked with at least two external accessories). Ranges  306  and  304  may be separated by a trigger gap  310  to ensure that there is adequate margin to help differentiate between the second scenario where one accessory is attached to device  100  and a third scenario where device  100  is attached or coupled to at least two accessories. In this illustrative example of  FIG. 9 , magnetic sensor  116  distinguishes between the attachment of zero, one, or multiple external accessories. 
     The near-field communications reader in device  100  may perform anti-collision operations when multiple external accessories are detected. For example, a first near-field communications tag in a first accessory and a second near-field communications tag in a second accessory may both want to transmit information to the reader of device  100 . When detecting such potential collision, the near-field communications reader of device  100  may communicate with only one of the tags while communications with the other tag is halted. After communications with the first tag is complete, the reader can then proceed to communicate with the second tag. 
     Other sensing techniques are possible. In some examples, multiple magnetic sensors may be used. In some examples, NFC communication can be used to detect the presence of multiple attached accessories once a magnetic sensor has indicated the presence of at least one attached accessory. In some embodiments, device  100  uses NFC to detect when one or more accessories have been attached, instead of magnetic sensor  116 . An NFC reader may periodically transmit NFC pings to detect whether an accessory has been coupled to the housing of device  100 . 
     Turning to  FIGS. 9 and 10 , exemplary techniques for communicating using NFC and wireless charging signals are described. Careful sequencing in the use of NFC and wireless charging signal can improve and mitigate interferences between the wireless operations.  FIG. 9  is a flow chart of illustrative processes for performing NFC communications by pausing wireless power handshake operations in accordance with some embodiments. 
     At block  400 , portable electronic device  100  is attached to an accessory such as wireless power transmitting device  12  of  FIG. 1 . At block  402 , the accessory detects the presence of portable electronic device  100 . At block  404 , power transmitting accessory  12  begins wireless power handshake operations with portable electronic device  100 . These handshaking operations may include authentication, negotiation of supported communication protocols and power transfer levels, and so forth. At block  406 , power transmitting accessory  12  pauses the wireless power handshake operations so that NFC communications can be performed between NFC components in devices  12  and  100 . In some embodiments these NFC communications include those described with reference to block  204  of  FIG. 7 . At block  408 , after the NFC communications, power transmitting accessory  12  resumes the wireless power handshake operations. At block  410 , after the needed handshake and power negotiation operations are performed, wireless power transmitting accessory  12  begins active wireless power transfer by sending wireless power signals at appropriate (e.g., negotiated) levels to portable electronic device  100 . During active wireless power transfer in block  410 , devices  12  and  100  may further communication with one another, such as via in-band communication, to convey control and/or feedback signals to sustain wireless power transfer. 
     The example of  FIG. 9  in which device  100  is attached to a power transmitting accessory is merely illustrative. As another example, device  100  can also be attached to an accessory such as power transmitting and receiving device  18  of  FIG. 1 . In such scenarios, device  100  can communicate with the accessory via near-field communications and determine whether to then either transmit wireless power to the accessory or receive wireless power from the accessory. 
       FIG. 10  is a flow chart of illustrative processes for performing near-field communications by pausing active, on-going wireless power transmission in accordance with some embodiments. In some embodiments, the NFC communications operations during block  204  of  FIG. 8  is performed after wireless power transmitting device  12  and portable electronic device  100  have negotiated for and begun wireless power transfer. 
     At block  500 , portable electronic device  100  is attached to an accessory such as wireless power transmitting device  12  of  FIG. 1 . At block  502 , wireless power transmitting accessory  12  detects the presence of portable electronic device  100 . At block  504 , wireless power transmitting accessory  12  begins wireless power handshake operations with portable electronic device  100 . These handshaking operations may include authentication, to negotiation of supported communication protocols and power transfer levels, so forth. At block  506 , after the handshake and power negotiation operations are performed, wireless power transmitting accessory  12  begins active wireless power transfer at appropriate (e.g., negotiated) levels. During operations of block  506 , the power transmitting accessory may transmit wireless power signals to device  100  via the wireless power charging coils and may optionally perform in-band communications to convey control and data signals between the two devices. 
     At block  508 , wireless power transmitting accessory  12  pauses the active wireless power transfer operations (e.g., by temporarily halting the wireless power transmission and operating the accessory in a wireless-power-transfer-halted mode). During the wireless-power-transfer-halted mode, near-field communications can be performed between the NFC circuitry in devices  12  and  100 . In some embodiments these NFC communications include those described with reference to block  204  of  FIG. 8 . At block  510 , after the needed NFC communications are performed, wireless power transmitting device  12  resumes active wireless power transfer operations. 
     Although the methods of operations are described in a specific order, it should be understood that other operations may be performed in between described operations, described operations may be adjusted so that they occur at slightly different times or described operations may be distributed in a system which allows occurrence of the processing operations at various intervals associated with the processing, as long as the processing of the overlay operations are performed in a desired way. 
     The foregoing describes exemplary embodiments of wireless power transfer systems utilizing NFC communications. This information can be beneficially used to control efficient wireless charging operations and to appraise users of characteristics of accessories that are inductively coupled with their device. It is contemplated that some implementers of the present technology may consider the passage of identifiers, such as serial numbers. UIDs, manufacturer IDs, MAC addresses, or the like, to aide in the identification and handling of devices in a wireless charging system. 
     Entities implementing the present technology should take care to ensure that, to the extent any sensitive information is used in particular implementations, that well-established privacy policies and/or privacy practices are complied with. In particular, such entities would be expected to implement and consistently apply privacy practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. Implementers should inform users where personally identifiable information is expected to be transmitted in a wireless power transfer system, and allow users to “opt in” or “opt out” of participation. For instance, such information may be presented to the user when they place a device onto a wireless power transmitter. 
     It is the intent of the present disclosure that personal information data, if any, should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, data de-identification can be used to protect a user&#39;s privacy. For example, a device identifier may be masked to convey the characteristics of the device without uniquely identifying the device. De-identification may be facilitated, when appropriate, by removing identifiers, controlling the amount or specificity of data stored, controlling how data is stored, and/or other methods such as differential privacy. For example, a dock that has been paired with a user device may identify itself using minimally required information, such as a byte value of 0x00000001. While devices that have been explicitly paired by the user may understand that 0x00000001 refers to a Kitchen dock, the bit value of 0x00000001 itself does not inherently convey this level of information. Robust encryption may also be utilized to reduce the likelihood that communication between inductively coupled devices are spoofed or intercepted. NFC authentication can provide additional protection by preventing certain information from being exchanged with an unauthorized NFC device. 
     Entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of any personal information data should comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. 
     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.

Metadata:
Filing Date: 20200922
Publication Date: 20210914
Grant Date: 20210914
Priority Date: 20200904
Inventors: PATEL, PARIN
KUMAR, DANIEL P.
CHANG, ANDREW C.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W12/47", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0047", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/00045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K19/0723", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K7/10297", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/47", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/60", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0047", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J7/00045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0047", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/00045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K19/0723", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K7/10297", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K7/10297", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0047", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K19/0723", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/0037", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/00045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/47", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/60", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0047", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J7/00045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 77665654