PATENT DOCUMENT

Publication Number: US-11239695-B2
Application Number: US-201916421291-A
Country: US
Kind Code: B2

Title: Wireless power system with device priority

Abstract:
A wireless power system may have a wireless power transmitting device and wireless power receiving devices. The wireless power transmitting device has wireless power transmitting circuitry with coils to transmit wireless power to wireless power receiving devices. The wireless power receiving devices are placed on the wireless power transmitting device in an order. Batteries in the wireless power receiving devices are charged based at least partly on the order. Power allocation is based on utilization factor information such as information on a power draw associated with each of the power receiving devices. Measurement circuitry in the wireless power transmitting device is used to gather impedance images from the coils. Changes in the impedance images are used to temporarily halt power transmission. Power transmission is resumed depending on whether in-band communications are lost or are maintained.

Claims:
What is claimed is: 
     
       1. A wireless power receiving device configured to wirelessly receive power during wireless power transmission from a wireless power transmitting device having a charging surface, comprising:
 wireless power receiving circuitry including a coil and a rectifier, wherein the rectifier is configured to receive wireless power signals with the coil and is configured to supply a corresponding output voltage; 
 a motion sensor; 
 a display; and 
 control circuitry configured to:
 monitor the output voltage to determine whether the wireless power transmission is present; 
 display a charging status indicator on the display when the wireless power transmission is determined to be present; and 
 in response to determining that the wireless power transmission has been lost, using the loss of wireless power transmission to trigger evaluation of data from the motion sensor to determine whether the wireless power receiving circuitry has been lifted away from the charging surface. 
 
 
     
     
       2. The wireless power receiving device of  claim 1  wherein the control circuitry is configured to continue to display the charging status indicator on the display for a debounce period that starts when the wireless power transmission is lost. 
     
     
       3. The wireless power receiving device of  claim 2  wherein the control circuitry is configured to monitor for resumption of the wireless power transmission during the debounce period. 
     
     
       4. The wireless power receiving device of  claim 3  wherein the control circuitry is configured to remove the charging status indicator from the display upon expiration of the debounce period without detection of resumption of the wireless power transmission during the debounce period. 
     
     
       5. A wireless power receiving device configured to wirelessly receive power during wireless power transmission from a wireless power transmitting device having a charging surface, comprising:
 wireless power receiving circuitry; 
 a motion sensor configured to produce motion sensor data; 
 a display; and 
 control circuitry configured to:
 display a charging status indicator on the display; and 
 monitor the wireless power receiving circuitry to determine whether the wireless power is being received; 
 in response to determining that the wireless power is not being received and that the motion sensor does not indicate that the wireless power receiving circuitry has been lifted from the charging surface, initiate a charging status indicator debounce period having a first value; and 
 in response to determining that the wireless power is not being received and that the motion sensor indicates that the wireless power receiving circuitry has been lifted from the charging surface, initiate a charging status indicator debounce period having a second value that is less than the first value. 
 
 
     
     
       6. The wireless power receiving device of  claim 5  wherein the control circuitry is configured to:
 display the charging status indicator for the entire charging status indicator debounce period; and 
 remove the charging status indicator at expiration of the charging status indicator debounce period when the wireless power is not received for the entire debounce period. 
 
     
     
       7. A wireless power receiving device configured to wirelessly receive power during wireless power transmission from a wireless power transmitting device having a charging surface, comprising:
 wireless power receiving circuitry including a coil and a rectifier, wherein the rectifier is configured to receive wireless power signals with the coil and is configured to supply a corresponding output voltage; 
 a three-axis accelerometer; 
 control circuitry configured to:
 monitor the output voltage; 
 transmit power adjustment commands to the wireless power transmitter based at least partly on the monitored output voltage; 
 monitor the three-axis accelerometer; and
 in response to determining that the wireless power transmission has decreased while the three-axis accelerometer indicates that the wireless power receiving device has not been moved vertically from the charging surface, transmit a power adjustment command to the wireless power transmitting device requesting an increased in transmitted power; and 
 in response to determining that the wireless power transmission has decreased while the three-axis accelerometer indicates that the wireless power receiving device has been moved vertically from, but not laterally on, the charging surface, cease transmitting the power adjustment commands. 
 
 
 
     
     
       8. The wireless power receiving device of  claim 7  further comprising a display that is configured to display a charging status indicator, wherein the control circuitry is configured to:
 remove the charging status indicator in response to determining that the wireless power transmission has decreased while the three-axis accelerometer indicates that the wireless power receiving device has been moved vertically from, but not laterally on, the charging surface; and 
 retain the charging status indicator in response to determining that the wireless power transmission has decreased while the three-axis accelerometer indicates that the wireless power receiving device has not been moved vertically from the charging surface. 
 
     
     
       9. One or more non-transitory, computer-readable media having instructions that, when executed by one or more processors, cause a device to:
 monitor a rectified output voltage to determine whether wireless power transmission is present; 
 display a charging status indicator when the wireless power transmission is present; 
 in response to determining that the wireless power transmission has been lost, using the loss of wireless power transmission to trigger evaluation of motion sensor data to determine whether the device has been lifted away from a charging surface of a wireless power transmitting device. 
 
     
     
       10. The one or more non-transitory, computer-readable media of  claim 9 , wherein the instructions, when executed, further cause the device to:
 continue to display the charging status indicator for a debounce period that starts when the wireless power transmission is lost. 
 
     
     
       11. The one or more non-transitory, computer-readable media of  claim 10 , wherein the instructions, when executed, further cause the device to:
 monitor for resumption of the wireless power transmission during the debounce period. 
 
     
     
       12. The one or more non-transitory, computer-readable media of  claim 11 , wherein the instructions, when executed, further cause the device to:
 stop displaying the charging status indicator upon expiration of the debounce period without detection of resumption of the wireless power transmission during the debounce period. 
 
     
     
       13. One or more non-transitory, computer-readable media having instructions that, when executed by one or more processors, cause a device to:
 display a charging status indicator; 
 produce motion sensor data; 
 monitor wireless power receiving circuitry in the device to determine whether wireless power is being received; 
 in response to determining that the wireless power is not being received and that the motion sensor data does not indicate that the wireless power receiving circuitry has been lifted from a charging surface of a wireless power transmitting device, initiate a charging status indicator debounce period having a first value; and 
 in response to determining that the wireless power is not being received and that the motion sensor data indicates that the wireless power receiving circuitry has been lifted from the charging surface, initiate a charging status indicator debounce period having a second value less than the first value. 
 
     
     
       14. The one or more non-transitory, computer-readable media of  claim 13 , wherein the instructions, when executed, further cause the device to:
 display the charging status indicator for the entire charging status indicator debounce period. 
 
     
     
       15. The one or more non-transitory, computer-readable media of  claim 14 , wherein the instructions, when executed, further cause the device to:
 stop displaying the charging status indicator at expiration of the charging status indicator debounce period when the wireless power is not received for the entire debounce period. 
 
     
     
       16. One or more non-transitory, computer-readable media having instructions that, when executed by one or more processors, cause a device to:
 monitor a rectified output voltage and accelerometer data; 
 transmit power adjustment commands to a wireless power transmitter based at least partly on the rectified output voltage; 
 in response to determining that wireless power transmission has decreased while the accelerometer data indicates that the device has not been moved vertically from a charging surface of the wireless power transmitter, transmit a power adjustment command to the wireless power transmitter requesting an increased in transmitted power; and 
 in response to determining that the wireless power transmission has decreased while the accelerometer data indicates that the device has been moved vertically from, but not laterally on, the charging surface, cease transmitting the power adjustment commands. 
 
     
     
       17. The one or more non-transitory, computer-readable media of  claim 16 , wherein the instructions, when executed, further cause the device to:
 display a charging status inductor. 
 
     
     
       18. The one or more non-transitory, computer-readable media of  claim 17 , wherein the instructions, when executed, further cause the device to:
 stop displaying the charging status indicator in response to determining that the wireless power transmission has decreased while the accelerometer data indicates that the device has been moved vertically from, but not laterally on, the charging surface. 
 
     
     
       19. The one or more non-transitory, computer-readable media of  claim 17 , wherein the instructions, when executed, further cause the device to:
 keep displaying the charging status indicator in response to determining that the wireless power transmission has decreased while the accelerometer data indicates that the device has not been moved vertically from the charging surface.

Description:
This application claims priority to U.S. provisional patent application No. 62/718,860 filed on Aug. 14, 2018, 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 electronic devices. 
     BACKGROUND 
     In a wireless charging system, a wireless charging mat wirelessly transmits power to a portable electronic device that is placed on the mat. The portable electronic device has a coil and rectifier circuitry. The coil receives alternating-current wireless power signals from a coil in the wireless charging mat that is overlapped by the coil in the portable electronic device. The rectifier circuitry converts the received signals into direct-current power. 
     SUMMARY 
     A wireless power system has a wireless power transmitting device. The wireless power transmitting device uses coils to transmit wireless power to wireless power receiving devices placed on the wireless power transmitting device. 
     The wireless power receiving devices are placed on the wireless power transmitting device in an order. Batteries in the wireless power receiving devices are charged based at least partly on the order. Power allocation between multiple power receiving devices is based on utilization factor information in addition to information on the order in which the power receiving devices are placed on the wireless power transmitting device. The utilization factor information includes a utilization factor value computed for each wireless power receiving device. The utilization factor value is computed by dividing the power draw of each device by the total power draw of all power receiving devices that are receiving wireless power from the wireless power transmitting device. 
     Measurement circuitry in the wireless power transmitting device is used to gather impedance readings such as impedance images from the coils. Changes in the impedance readings (e.g., changes to impedance images) cause the wireless power transmitting device to temporarily halt power transmission. Power transmission may be resumed depending on whether in-band communications are lost or are maintained. 
     In accordance with embodiments, control circuitry in the wireless power receiving device monitors the output voltage of a rectifier in the wireless power receiving device to determine whether wireless power transmission has been interrupted. A charging status indicator is displayed on the wireless power receiving device when wireless power is being received. A charging status indicator debounce period may be used to help prevent flickering in the charging status indicator. The debounce period may be adjusted depending on whether detected power losses are due to a user lifting the wireless power receiving device and its wireless power receiving circuitry away from a charging surface of the wireless power transmitting device or are not due to user lifting of the receiving device and its circuitry. This ensures that sufficiently long debounce periods are available to prevent undesired charging status indicator flickering while shortening the debounce period to enhance the responsiveness of the indicator when a user lifts the receiving device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative wireless charging system that includes a wireless power transmitting device and a wireless power receiving device in accordance with an embodiment. 
         FIG. 2  is a top view of an illustrative wireless power transmitting device having a charging surface on which wireless power receiving devices are placed in accordance with an embodiment. 
         FIG. 3  is a diagram of an illustrative charging priority table in accordance with an embodiment. 
         FIG. 4  is flow chart of illustrative operations involved in using the wireless charging system of  FIG. 1  to charge wireless power receiving devices in accordance with an embodiment. 
         FIG. 5  is a flow chart of illustrative operations involved in using motion information in adjusting a charging status indicator debounce period for a wireless power receiving device in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A wireless power system includes a wireless power transmitting device such as a wireless charging mat. The wireless power transmitting device wirelessly transmits power to one or more wireless power receiving devices. The wireless power receiving devices may include devices such as wristwatches, cellular telephones, tablet computers, laptop computers, ear buds, battery cases for ear buds and other devices, tablet computer pencils and other input-output devices, wearable devices, or other electronic equipment. The wireless power receiving devices use power from the wireless power transmitting device for powering internal components and for charging an internal battery. Because transmitted wireless power is often used for charging internal batteries, wireless power transmission operations are sometimes referred to as wireless charging operations. 
     The wireless power transmitting device communicates with each wireless power receiving device and obtains information on the characteristics of each wireless power receiving device. The wireless power transmitting device uses information from wireless power receiving devices and measurements made in the wireless power transmitting device to establish a satisfactory wireless charging scheme. Factors that are taken into account in setting up charging in the wireless charging system include battery charge state, the ability of devices to receive power (e.g., power drawn be the devices), the order in which power receiving devices are placed in range of the wireless power transmitting device, and other information. 
     An illustrative wireless power system (wireless charging system) is shown in  FIG. 1 . As shown in  FIG. 1 , wireless power system  8  includes a wireless power transmitting device such as wireless power transmitting device  12  and includes a wireless power receiving device such as wireless power receiving device  24 . Wireless power transmitting device  12  includes control circuitry  16 . Wireless power receiving device  24  includes control circuitry  30 . Control circuitry in system  8  such as control circuitry  16  and control circuitry  30  is used in controlling the operation of system  8 . This control circuitry 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. The processing circuitry implements desired control and communications features in devices  12  and  24 . For example, the processing circuitry may be used in selecting coils, determining power transmission levels, processing sensor data and other data, processing user input, handling negotiations between devices  12  and  24 , sending and receiving in-band and out-of-band data, making measurements, and otherwise controlling the operation of 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  and/or  30 . 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 that includes power adapter circuitry), may be a wireless charging mat that is coupled to a power adapter or other equipment by a cable, may be a portable electronic device (cellular telephone, tablet computer, laptop computer, etc.), may be equipment that has been incorporated into furniture, a vehicle, or other system, or may be other wireless power transfer equipment. Illustrative configurations in which wireless power transmitting device  12  is a wireless charging mat 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, a battery case, 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 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. In some configurations, AC-DC power converter  14  may be provided in an enclosure (e.g., a power brick enclosure) that is separate from the enclosure of device  12  (e.g., a wireless charging mat enclosure) and a cable may be used to couple DC power from the power converter to device  12 . DC power may be used to power control circuitry  16 . During operation, a controller in control circuitry  16  may use 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  60  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 transmit coils  42 . Coils  42  may be arranged in a planar coil array (e.g., in configurations in which device  12  is a wireless charging mat). The coils may be arranged in multiple layers (e.g., three layers or any other suitable number of layers) and each of the multiple layers may have coils that overlap coils in other layers. 
     As the AC currents pass through one or more coils  42 , alternating-current electromagnetic (e.g., magnetic) fields (signals  44 ) are produced that are received by one or more corresponding receiver coils such as coil  48  in power receiving device  24 . When the alternating-current electromagnetic fields are received by coil  48 , corresponding alternating-current currents are induced in coil  48 . Rectifier circuitry such as rectifier  50 , 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 coil  48  into DC voltage signals for powering device  24 . 
     The DC voltages produced by rectifier  50  can be used in powering an energy storage device such as battery  58  and can be used in powering other components in device  24 . For example, device  24  may include input-output devices  56  such as a display, touch sensor, communications circuits, audio components, sensors, and other components and these components may be powered by the DC voltages produced by rectifier  50  (and/or DC voltages produced by battery  58  or other energy storage device in device  24 ). 
     Device  12  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 to device  24  using an antenna. Wireless transceiver circuitry  40  may be used to wirelessly receive out-of-band signals from device  24  using the antenna. Device  24  may have wireless transceiver circuitry  46  that transmits out-of-band signals to device  12 . Receiver circuitry in wireless transceiver  46  may use an antenna to receive out-of-band signals from device  12 . 
     Wireless transceiver circuitry  40  can use one or more coils  42  to transmit in-band signals to wireless transceiver circuitry  46  that are received by wireless transceiver circuitry  46  using coil  48 . Any suitable modulation scheme may be used to support in-band communications between device  12  and device  24 . With one illustrative configuration, frequency-shift keying (FSK) is used to convey in-band data from device  12  to device  24  and amplitude-shift keying (ASK) is used to convey in-band data from device  24  to device  12 . Power may be conveyed wirelessly from device  12  to device  24  during these FSK and ASK transmissions. Other types of in-band communications may be used, if desired. 
     During wireless power transmission operations, circuitry  52  supplies AC drive signals to one or more coils  42  at a given power transmission frequency. The power transmission frequency may be, for example, a predetermined frequency of about 125 kHz, at least 80 kHz, at least 100 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. 
     During wireless power transfer operations, while power transmitting circuitry  52  is driving AC signals into one or more of coils  42  to produce signals  44  at the power transmission frequency, wireless transceiver circuitry  40  uses 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  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  42  and  48  while power is simultaneously being wirelessly conveyed from device  12  to device  24  using coils  42  and  48 . Other types of in-band communications between device  12  and device  24  may be used, if desired. 
     In-band communications between device  24  and device  12  uses ASK modulation and demodulation techniques or other suitable in-band communications 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)  42 . Wireless transceiver circuitry  40  monitors the amplitude of the AC signal passing through coil(s)  42  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  42  while power is simultaneously being wirelessly conveyed from device  12  to device  24  using coils  42  and  48 . 
     Control circuitry  16  has external object measurement circuitry  41  (sometimes referred to as foreign object detection circuitry or external object detection circuitry) that detects external objects on a charging surface associated with device  12 . 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 . During object detection and characterization operations, external object measurement circuitry  41  can be used to make measurements on coils  42  to determine whether any devices  24  are present on device  12  (e.g., whether devices  24  are suspected to be present on device  12 ). In capturing data from an array of coils  42 , a pattern is formed, which is sometimes referred to as an impedance image or inductance image. The image may be processed by system  8  to determine which power transmission settings to use for transmitting power, etc. For example, the image can be processed to detect movement of devices  24  (in which case power transmission can be momentarily halted). 
     In an illustrative arrangement, measurement circuitry  41  of control circuitry  16  contains signal generator circuitry (e.g., oscillator circuitry for generating AC probe signals at one or more probe frequencies, a pulse generator, etc.) and signal detection circuitry (e.g., filters, analog-to-digital converters, impulse response measurement circuits, etc.). During measurement operations, switching circuitry in device  12  may be adjusted by control circuitry  16  to switch each of coils  42  into use. As each coil  42  is selectively switched into use, control circuitry  16  uses the signal generator circuitry of signal measurement circuitry  41  to apply a probe signal to that coil while using the signal detection circuitry of signal measurement circuitry  41  to measure a corresponding response. Measurement circuitry  43  in control circuitry  30  and/or in control circuitry  16  may also be used in making current and voltage measurements. 
     The characteristics of each coil  42  depend on whether any foreign objects overlap that coil (e.g., coins, wireless power receiving devices, etc.) and also depend on whether a wireless power receiving device with a coil such as coil  48  of  FIG. 1  is present, which could increase the measured inductance of any overlapped coil  42 . Signal measurement circuitry  41  is configured to apply signals to the coil and measure corresponding signal responses. For example, signal measurement circuitry  41  may apply an alternating-current probe signal while monitoring a resulting signal at a node coupled to the coil. As another example, signal measurement circuitry  41  may apply a pulse to the coil and measure a resulting impulse response (e.g., to measure coil inductance). Using measurements from measurement circuitry  41 , the wireless power transmitting device can determine whether an external object is present on the coils. If, for example, all of coils  42  exhibit their expected nominal response to the applied signals, control circuitry  16  can conclude that no external devices are present. If one of coils  42  exhibits a different response (e.g., a response varying from a normal no-objects-present baseline), control circuitry  16  can conclude that an external object (potentially a compatible wireless power receiving device) is present. 
     Control circuitry  30  has measurement circuitry  43 . In an illustrative arrangement, measurement circuitry  43  of control circuitry  30  contains signal generator circuitry (e.g., oscillator circuitry for generating AC probe signals at one or more probe frequencies, a pulse generator, etc.) and signal detection circuitry (e.g., filters, analog-to-digital converters, impulse response measurement circuits, etc.). During measurement operations, device  24  may use measurement circuitry  43  to make measurements to characterize device  24  and the components of device  24 . For example, device  24  may use measurement circuitry  43  to measure the inductance of coil  48  (e.g., signal measurement circuitry  43  may be configured to measure signals at coil  48  while supplying coil  48  with signals at one or more frequencies (to measure coil inductances), signal pulses (e.g., so that impulse response measurement circuitry in the measurement circuitry can be used to make inductance and Q factor measurements), etc. Measurement circuitry  43  may also make measurements of the output voltage of rectifier  50 , the output current of rectifier  50 , etc. 
     A top view of an illustrative configuration for device  12  in which device  12  has an array of coils  42  is shown in  FIG. 2 . Device  12  may, in general, have any suitable number of coils  42  (e.g., 22 coils, at least 5 coils, at least 10 coils, at least 15 coils, fewer than 30 coils, fewer than 50 coils, etc.). Coils  42  may be arranged in rows and columns and may or may not partially overlap each other. In the example of  FIG. 2 , there are three layers of coils  42  and the coils in each layer partially overlap coils in other layers. Other arrangements may be used, if desired. 
     As shown in  FIG. 2 , one or more devices  24  may be placed on device  12  (e.g., on coils  42 ). Device  24  may have a display such as display  56 D or other visual output device in input-output devices  56 . Display  56 D may be used to display information such as information  45 . Information  45  may include text, icons, and/or other content. In some embodiments, information  45  may include information on whether wireless power transmission operations are active in system  8  (e.g., charging status information such as a green battery icon or other information indicating that device  12  is transmitting wireless power that device  24  is receiving for charging battery  58 , etc.). 
     System  8  may be configured to accommodate the simultaneous charging of multiple devices  24 . During operation, a user may place a first device  24  followed by a second device and potentially additional devices in a particular order. In order to meet the user&#39;s expectations about charging behavior and enhance charging operations, information may be gathered such as information on the order in which devices  24  were placed on device  12  and other information on the various devices  24  that are available to be charged in system  8  and charging parameters associated with each device. With one illustrative arrangement, system  8  maintains information on the charging of devices  24  in a priority table (sometimes referred to as charging priority table, wireless power transfer priority table, wireless power transmission priority information, device charging priority information, etc.). 
       FIG. 3  is a diagram of an illustrative priority table. As shown in  FIG. 3 , the priority table may, as an example, include information such as an identifier (ID) that identifies each device  24 . As an example, if two devices  24  are placed on device  12  for charging, the priority table will contain first and second rows with first and second entries corresponding respectively IDs for devices A and B. Additional information may be include in the entry for each device. For example, information may be included on whether each device  24  is to be charged by device  12  (indicated by a “Yes” entry in the row of the priority table corresponding to device A in the example of  FIG. 3 ) or is to be denied wireless power (indicated by a “No” entry in the row of the priority table corresponding to device B in the example of  FIG. 3 ). Information such as the order in which devices  24  were placed on device  12  can be included in the priority table, if desired (e.g., by adding each newly placed device  24  to a respective row at the bottom of the table in order). Additional information may be included if desired (e.g., information on the amount of power currently being drawn be each device  24  that is receiving power, etc.). Using the information of the priority table, system  8  performs operations such as deciding which devices  24  should be provided with wireless power, the priority to be given to each device  24  when providing wireless power, wireless power transmission levels, and other activities associated with transferring power between device  12  and one or more of devices  24 . 
       FIG. 4  is a flow chart of illustrative operations associated with managing the transfer of power with system  8 . 
     During the operations of block  80 , the power transmission capability of transmitting device  12  is determined and retained for later use. The power transmission capability of device  12  is determined at least partly by the power rating of AC-DC converter  14 . The power transmission capability of device  12  may be 10 W, at least 5 W, 10-30 W, less than 40 W, less than 30 W, or other suitable power. Information such as the power transmission capacity of device  12 , priority table information, and other information associated with the operation of system  8  may be stored on device  12 , one or more of devices  24 , and/or on remote storage (e.g., storage coupled to components in system  8  via the internet or other network(s)). Processing operations for system  8  may be performed using processing circuitry in system  8  such as control circuitry  16  and/or control circuitry  30  or other suitable processing circuitry. 
     A user may place one or more devices  24  on device  12 , so that these devices may be charged by device  12 . To determine when devices  24  are placed on device  12 , device  12  may use measurement circuitry  41  to perform object detection operations during the operations of block  82 . Measurement circuitry  41  may, for example, make low-power coil impedance measurements for coils  42  to determine when an external object has been placed on device  12 . The low-power measurements may be made by applying a probe signal of a frequency of at least 500 kHz, less than 1.5 MHz, or other suitable frequency to each coil  42  while monitoring the resulting voltage on that coil. 
     In response to detection of placement of an object (e.g., a device  24 ) on device  12 , additional impedance readings are gathered at block  84 . The impedance readings of block  84  can include the results of impulse response measurements with circuitry  41  that determine the impedance (e.g., the inductance) of each coil  42 . By gathering readings from each of coils  42 , an inductance image is obtained. Image processing operations are then performed on the captured impedance image to determine whether the image contains an inductance pattern that is suspected to correspond to one of devices  24 . If the pattern of inductance measurements in the image is not recognized as corresponding to any suspected devices  24  (e.g., of no objects are detected in the image or if an object is detected in the image that corresponds to a coin or other foreign object), system  8  can revert to lower power operations (e.g., monitoring the charging surface of device  12  using low-power measurements during the operations of block  82 ). If, however, the impedance image is recognized as containing a pattern that corresponds to a suspected device  24 , device  12  attempts to establish a communications link with the device. For example, device  12  may attempt to establish an in-band communications link with the detected device  24  (e.g., using the coil(s)  42  overlapped by the detected device  24 ). 
     After establishing one or more in-band communications links with one or more devices  24 , device  12  may, during the operations of block  86 , authenticate one or more devices  24 . An identifier (sometimes referred to as a receiving device identifier or receiver ID) is obtained for each wireless power receiving device  24  in communication with device  12 . A priority table in device  12  is updated accordingly (e.g., missing devices  24  can be removed from the priority table). Entries for new devices  24  are added to the priority table in a suitable priority order. If, as an example, the priority table is organized so that the device in the first row of the table has a greater priority than the device in the second row of the table (and so on for addition rows), newly added devices  24  can be represented by adding entries to the bottom rows of the priority table in the order in which these devices are authenticated. In this way, charging priority can be given to the earliest device or devices placed on device  12 . As an example, if a user places a phone, watch, and earbuds on device  12  (in that order), system  8  may give priority to the phone over the watch and may give priority to the watch over the earbuds. 
     There is a limited amount of power available for wireless charging in system  8 , so the charging status of each of the devices  24  listed in the priority table is preferably determined based at least partly on the power capability of device  12  that was recorded during the operations of block  80 . If, as an example, device  12  has a 10 W capacity and two cellular telephones are being charged by device  12 , the placement of a third cellular telephone on the mat may create a situation in which there is insufficient capacity to charge the third cellular telephone at a reasonable rate without adversely affecting the charging of the first two cellular telephones. The determination of whether there is sufficient power available to charge a given device  24  can be made based on the known power capability of device  12  to the power needs of the various devices  24  that desire power from device  12  and the priority table entries indicating which devices have priority and are being charged. If the available power from device  12  does not exceed a predetermined threshold or if it is otherwise determined that there is insufficient power to charge a newly placed device with reasonable speed, charging for that device is denied and the priority table is updated accordingly. In particular, devices that are not to be charged are provided with “No” entries in the priority table. Devices with priority that are to be charged have “Yes” entries. 
     During the operations of block  88 , device  12  directs the power receiving devices  24  that are to be charged (the “Yes” entries) to display battery charging information (e.g., a battery charge indicator) on their displays (e.g., displays in input-output devices  56  of  FIG. 1 ), if these devices had not been previously instructed to display battery charging information. Devices that cannot be charged because of insufficient power available from device  12  can be instructed by device  12  to display error messages (e.g., an icon or other information that indicates that charging operations are not being performed due to insufficient power). 
     During the operations of block  90 , devices  24  are charged in accordance with information in the priority table while device  12  uses measurement circuitry  41  to continue to capture impedance readings (e.g., impedance images) of the devices on coils  42 . Each device  24  on device  12  continues to display charging information (e.g., “currently charging” or “currently not charging” icons or other charging messages). Missing devices (devices in the priority table for which no in-band link is present) are ignored. If a device loses its in-band link for more than a predetermined amount of time (e.g., 2 s or other suitable threshold amount), the device is deleted from the priority table (e.g., the table is updated to include only those devices that are present and have satisfactory in-band links). The impedance image information captured during the operations of block  90  is analyzed to determine whether there are any changes (e.g., by using image processing techniques to evaluate whether the current image differs by more than a threshold amount from the previous image). If no change to the impedance image is detected, power transmission can be resumed at block  90 . If a change in the impedance image is detected, processing can proceed to the operations of block  92 . 
     During block  92 , in response to determining that the impedance image has changed, device  12  system  8  can temporarily halt power transmission to one or more of devices  24 . For example, power transmission can be briefly interrupted for all devices  24 . To prevent undue changes in the charging icons on devices  24 , these icons (or other displayed messages containing charging status information and other information on the operation of system  8 ) may be maintained in their current state, pending analysis of the status of the in-band communications links between device  12  and devices  24 . 
     If device  12  determines that the in-band links with devices  24  have been maintained (e.g., all links have been maintained) despite the detected change in the impedance image, devices  24  may continue to be charged and the priority table entries for devices  24  may each remain with a “Yes” entry. Charging (wireless power transfer operations) can then be resumed at block  90 . In response to determining that one or more in-band links have been lost, however, device  12  can return to the operations of block  84  (and may, if desired, attempt to instruct the device that has been delinked and/or other devices  24  to remove any corresponding displayed battery charging icon). During block  84 , device  12  can attempt to reestablish in-band links with suspected devices identified in the inductance image after which charging operations may be resumed as appropriate. 
     In accordance with the operations of  FIG. 4 , charging operations need not be disrupted when devices  24  are moved slightly during charging. For example, if a device  24  is inadvertently bumped and moves slightly (e.g., a small distance within the plane of the charging surface associated with device  12 ), the in-band link between that device  24  and device  12  will not be lost. As a result, power transfer will only momentarily be halted (e.g., during block  92  without changing the visual appearance of the charging icons or other charging information displayed on device  24  for the user) before being resumed normally (block  90 ). The visual appearance of the charging icons or other charging information displayed on device  24  may also remain unchanged in scenarios in which device  24  is bumped sufficiently to lose its in-band link but regains its in-band link at block  84  quickly (e.g., within 2 s or other suitable threshold time). If, on the other hand, a device  24  is lifted fully off of device  12  or otherwise loses its in-band link for more than the threshold amount of time (e.g., 2 seconds), power transfer will be halted at block  92  and device  12  may remove the display of the charging icon or other charging information from device  24 . Movements in which in-band communications are not lost will not disrupt the ordering of entries in the priority table, so these movements will allow devices  24  to continue to be charged in accordance with the order in which they were placed on device  12 . Movements that result in loss of in-band communications for more than a predetermined amount of time (e.g., 2 seconds) may cause devices  24  to be removed from the priority table, so that these devices will receive the lowest priority of the devices being charged when replaced on device  12 . 
     In an illustrative embodiment, the charging icons or other charging information displayed on device  24  (sometimes referred to as charging status information) may be displayed for a debounce period following loss of wireless power transmission between device  12  and device  24 . By imposing a debounce period before changing the visual appearance of the charging icons or other charging information displayed on device  24 , undesirable flickering of the charging icon on device  24  can be avoided. If, as an example, a user slides device  24  across the surface of a mat or other device  12 , in-band communications with the currently overlapped coil in device  12  may be interrupted and charging momentarily paused (e.g., device  12  may momentarily halt wireless power transmission). However, the in-band link may be reestablished with a new coil and charging resumed. If the in-band link is reestablished with the new coil and wireless power transmission is resumed within the debounce period, the visible appearance of the charging icons or other charging information displayed on device  24  need not change. In this way, a user who slides device  24  around on the surface of device  12  may not experience undesired flickering of the charging icon or other displayed charging information. As another example, device  12  may occasionally halt transmission of wireless power so that measurement circuitry  41  can perform coil measurements or other operations while power is not being transmitted to device  24 . In this situation, the debounce period prevents the charging status indicator from being removed during a brief pause in power transmission. 
     Long debounce periods help provide sufficient time for control circuitry in device  12  to conduct coil measurements and other operations that are performed during periods of time in which transmission of wireless power is momentarily halted. Long debounce periods also help prevent charging status indicator flickering when a user is sliding device  24  around on the surface of device  12 . Short debounce periods allow the charging status indicator to be removed from the display of device  24  rapidly following power loss, thereby providing a user with status information that is rapidly updated. System  8  may use a fixed debounce period or, to help accommodate both of these desires, a debounce period in system  8  may be adjusted based on whether a detected power loss in device  24  is due to user movement of device  24  relative to device  12  (e.g., movement of wireless power receiving circuitry  54  away from the charging surface associated with device  12  and away from power transmitting circuitry  52 ) or termination of power transmission by device  12 . 
     In embodiments with an adjustable debounce period, input-output devices  56  include a motion sensor (e.g., an accelerometer, an inertial measurement unit that includes an accelerometer, gyroscope, and/or compass, and/or other sensors for detecting changes in orientation and/or position of device  12 ). Following a detected power loss, control circuitry  30  analyzes data from the motion sensor to determine whether device  12  has experienced motion of the type that is associated with user removal of device  24  from the charging surface of device  12  (e.g., vertical lifting motions in the Z dimension of  FIG. 2 ) or has not experienced this type of motion (in which case device  12  can be assumed to have lost power due to a wireless power transmitting device depowering event not associated with user device removal such as depowering to perform coil measurements or depowering because the user is sliding device  24  on the surface of device  12  in the X-Y plane). Control circuitry  30  then adjusts the debounce period to a longer value (in response to detection of a loss of power not due to lifting during a user removal event) or a smaller value (in response to detection of a loss of power due to a user removal event). 
     A flow chart of illustrative operations associated with implementing an adjustable charging status indicator debounce period in system  8  are shown in  FIG. 5 . After a user places device  24  on the charging surface of device  12 , control circuitry  16  of device  12  uses power transmitting circuitry  52  to transmit wireless power and power receiving device  24  receives the transmitted wireless power with power receiving circuitry  54 . When control circuitry  30  senses receipt of wireless power, control circuitry  30  uses a display in input-output devices  56  (or other charge status output device in input-output devices  56 ) to display a charging indicator (e.g., a charging icon, informative text, etc.) for the user. This informs the user that the process of transferring wireless power from device  12  to device  24  (e.g., to charge battery  58 ) is active. 
     During the operations of block  100 , while the charging status indicator is being displayed, device  24  uses control circuitry  30  to monitor power receiving circuitry  54  to determine whether power is being received. Control circuitry  30  may, for example, monitor the output voltage of rectifier  50 . If the rectifier output stays at its normal operating level, monitoring operations may continue at block  100 . 
     If, however, wireless power transmission is interrupted and the output voltage of rectifier  50  drops, control circuitry  30  may, during the operations of block  102 , determine whether the loss of wireless power is due to a user lifting device  24  off of the charging surface of device  12 . Control circuitry  30  may, for example, analyze the Z-axis (vertical) accelerometer data of a three-axis accelerometer in input-output devices  56  to determine whether device  24  has been moved vertically. If device  24  has not been moved or has only been moved laterally in the X-Y plane of  FIG. 2  (e.g., parallel to the charging surface of device  12 ), recent Z-axis measurements will indicate little or no movement Z-axis movement. If, on the other hand, device  24  has been lifted by a user, the recent Z-axis measurements will contain data indicative of vertical motion of device  24  away from device  12 . 
     In response to determining that the detected loss of power is due to user removal of device  24  (e.g., vertical movement of device  24  out of wireless power reception range by a user), device  24  can set the debounce period for the charging status indicator to a first debounce period value (e.g., 1.5 seconds or other suitable time period) during the operations of block  104 . In some embodiments, device  24  may send periodic power adjustment commands to device  12  that direct device  12  to increase or decrease power transmission. In this type of arrangement, device  24  may, in response to determining that a detected reduction in power transmission is due to user removable of device  24 , cease the transmission of such power adjustment commands to device  12  (e.g., device  24  can stop instructing device  12  to transmit desired amounts of power when device  24  is lifted from the charging surface and can no longer receive power). A charging status indicator that is being displayed on the display of device  24  can be removed in response to determining that the wireless power transmission has decreased while the motion sensor indicates that the wireless power receiving device has been lifted from the charging surface. 
     In response to determining that the detected loss of power is not due to user removal, device  24  can set the debounce period to a second debounce period value (e.g., 3 seconds or other suitable time period that is longer than the first debounce period) during the operations of block  106 . In embodiments in which device  24  sends periodic power adjustment commands to device  12  to request an increase or decrease in power transmitted from device  12 , device  24  may, in response to determining that a detected reduction in power transmission is not due to user removal, continue to communicate with device  12  regarding power transmission operations. For example, after confirming that a detected power drop is not due to user removal, device  24  may transmit a power increase request to device  12  that directs device  12  to increase the amount of power being wirelessly transmitted to device  24 . A charging status indicator that is being displayed on the display of device  24  can be retained (for at least some period of time such as at least 0.5 seconds, at least 10 seconds, less than 2 minutes, less than 30 seconds, less than 3 seconds, etc.) in response to determining that the wireless power transmission has decreased while the motion sensor indicates that the wireless power receiving device has not been lifted from the charging surface. 
     During the debounce period (block  108 ), control circuitry  30  continues to display the charging status indicator on the display of device  24  (e.g., the charging status indicator is not removed from the display, even though a power loss was detected during the operations of block  100 ). This prevents undesired flickering in the charging status indicator in the event that power is received intermittently. Control circuitry  30  of power receiving device  24  monitors wireless power receiving circuitry  54  (e.g., control circuitry  30  monitors the output voltage of rectifier  50 ) during the operations of block  108  to determine whether power has been restored. If power transmission is resumed (continuously or even briefly in the event that power transmission device  12  issues a brief keep-alive pulse to ensure that the charging status indicator remains displayed), the charging status indicator continues to be displayed and further operations are performed at block  100 . If power transmission is not resumed during block  108  and the debounce period expires, control circuitry  30  removes the charging status indicator from the display of device  24  during the operations of block  110 . 
     If desired, system  8  may protect against coupling variations between power transmitting device  12  and receiving devices  24  by proportionally allocating transmitted power to devices  24 . With one illustrative configuration, power is allocated in accordance with utilization factor information. For example, a utilization factor UF may be calculated by device  12  for each device  24  in accordance with the following equation:
 
UF=(transmitted power drawn by receiving device)/(total power allocated to receiving device)
 
The amount of power that is drawn by each device  24  is influenced by factors such as the battery condition, device operating temperature (battery temperature), coupling variations, etc. By computing a utilization factor for each device and using this information in allocating transmitted power, power can be allocated effectively.
 
     Consider, as an example, a scenario in which two cellular telephones (phone A and phone B) are placed on device  12 . Device  12  may have a 10 W capacity. Initially, each device might be capable of drawing 7.5 W, but will only receive 5 W each due to the power delivery limitation of device  12 . Phone B may have heat up more rapidly than phone A during charging. As a result, after a period of charging, phone A may demand (or draw) 5 W of power (using 100% of its allocated power), whereas phone B may demand (draw) only 3 W (due to its higher temperature and resulting lowered power draw). In this situation, the utilization factor UFA for phone A will be 5/10 and the utilization factor UFB for phone B will be 3/10. Power can then be allocated in accordance with the following equations:
 
Power allocated to phone  A =10 W*UF1/(UF1+UF2)
 
Power allocated to phone  B =10 W*UF2/(UF1+UF2)
 
     By allocating power in this way, devices  24  that are drawing less power (e.g., due to coupling variations, thermal considerations, battery parameters, etc.) will receive less allocated power than devices that are drawing more power. This utilization-factor-based allocation arrangement or other suitable power transmission allocation technique may be applied to each of the devices  24  that are listed in the priority table as being charged (“Yes” entries) during the operations of blocks  88  and  90  (e.g., when determining whether sufficient power is available to charge devices at a reasonable rate and when charging devices in accordance with the priority table). 
     The foregoing describes a technology in which data, such as information about whether a wireless power receiving device is moved, is transmitted during wireless power transmission to facilitate battery charging operations. On the topic of data transfer, it is noted (out of an abundance of caution) that entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of personal information data should comply with well-established privacy policies and/or privacy practices, if the present technology is utilized to transfer such data. 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. For instance, in the United States, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA), whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     To the extent that the present technology is leveraged to transmit personal information data, hardware and/or software elements can be provided for users to selectively block the use of, or access to, personal information data. For example, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an application (“app”) that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. It is also possible for a user to be prompted on whether or not to begin wireless charging operations should a wireless power provider request such personal information. 
     It is the intent of the present disclosure to describe a robust wireless power system involving data transmission. In implementations of this technology where personal information data is transmitted, that personal information data 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. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., unique device identifiers, usernames, etc.), controlling the amount or specificity of data stored (e.g., collecting location data at a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     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: 20190523
Publication Date: 20220201
Grant Date: 20220201
Priority Date: 20180814
Inventors: Thirumalai Ananthan Pillai, Srinivasa V.
RONDININI, Marco
CRETELLA, MICHAEL A.
YE, DANIEL
TOLVA, CORTLAND S.
Assignee: APPLE INC
CPC Classifications: [{"code": "H02J50/90", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/00045", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J7/0048", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/263", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0048", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/00045", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/0037", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/0047", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/60", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/77", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/26", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 69523550