PATENT DOCUMENT

Publication Number: US-11362548-B1
Application Number: US-202016942161-A
Country: US
Kind Code: B1

Title: Wireless power system cabling

Abstract:
A wireless power system has a wireless power transmitting device such as a charging puck and a wireless power receiving device such as a wristwatch. The charging puck may have a three-wire cable that is coupled between a connector and a puck housing. The wireless power transmitting device may have a set of four coils or other number of wireless power transmitting coils in the puck housing. A switch may be coupled in series with each of the four coils. Control circuitry in the wireless power transmitting device may activate a subset of the switches to switch a subset of the coils into use in transmitting the wireless power to the wireless power receiving device. The control circuitry may have a main portion in the connector that uses a tone-based encoding scheme or other encoding scheme to transmit switch configuration commands to a secondary portion in the puck housing.

Claims:
What is claimed is: 
     
       1. A wireless power transmitting device configured to wirelessly transmit power to a wireless power receiving device, comprising:
 a housing having one or more wireless power transmitting coils; 
 a connector having contacts configured to receive direct-current power from an external power port; 
 a cable connected between the connector and the housing that does not carry direct-current signals; and 
 control circuitry in the connector that is configured to provide alternating-current signals to the one or more wireless power transmitting coils through the cable that cause the one or more wireless power transmitting coils to transmit wireless power signals to the wireless power receiving device. 
 
     
     
       2. The wireless power transmitting device of  claim 1  wherein the cable has no more than a first number of wires, wherein the housing has no more than a second number of the one or more wireless power transmitting coils, and wherein the first number is less than the second number. 
     
     
       3. The wireless power transmitting device of  claim 1  further comprising power harvesting circuitry in the housing that is coupled to the cable and that produces direct-current power. 
     
     
       4. The wireless power transmitting device of  claim 3  wherein the wireless power transmitting device comprises switching circuitry in the housing and comprises control circuitry in the housing that controls the switching circuitry using the direct-current power. 
     
     
       5. The wireless power transmitting device of  claim 4 , wherein the one or more wireless power transmitting coils comprises at least two wireless power transmitting coils and wherein the switching circuitry comprises:
 switches that are respectively coupled to each of the at least two wireless power transmitting coils, wherein the control circuitry in the housing is configured to activate a selected subset of the switches to switch a corresponding subset of the at least two wireless power transmitting coils into use in transmitting the wireless power signals to the wireless power receiving device. 
 
     
     
       6. The wireless power transmitting device of  claim 5  wherein the control circuitry in the connector is configured to transmit commands to the control circuitry in the housing. 
     
     
       7. The wireless power transmitting device of  claim 4  wherein the control circuitry in the connector includes impulse measurement circuitry configured to supply impulses to the one or more wireless power transmitting coils and wherein the power harvesting circuitry receives the impulses and produces the direct-current power from the impulses. 
     
     
       8. The wireless power transmitting device of  claim 1  wherein the one or more wireless power transmitting coils include a first wireless power transmitting coil, a second wireless power transmitting coil, a third wireless power transmitting coil, and a fourth wireless power transmitting coil and wherein the wireless power transmitting device comprises switches in the housing that include a first switch coupled to the first wireless power transmitting coil, a second switch coupled to the second wireless power transmitting coil, a third switch coupled to the third wireless power transmitting coil, and a fourth switch coupled to the fourth wireless power transmitting coil. 
     
     
       9. The wireless power transmitting device of  claim 1  wherein the housing comprises a puck housing, the wireless power transmitting device further comprising a magnet in the puck housing that is configured to attract a corresponding magnet in the wireless power receiving device. 
     
     
       10. The wireless power transmitting device of  claim 1  wherein the one or more wireless power transmitting coils comprises at least two wireless power transmitting coils, the wireless power transmitting device further comprising four switches in the connector that form first and second half-bridge driver circuits configured to drive alternating-current signals to a subset of the at least two wireless power transmitting coils. 
     
     
       11. The wireless power transmitting device of  claim 10  wherein the control circuitry in the connector is configured to control the first and second half-bridge driver circuits to adjust a relative phase between 1) an alternating-current signal supplied to a first wireless power transmitting coil in the subset of the at least two wireless power transmitting coils and 2) an alternating-current signal supplied to a second wireless power transmitting coil in the subset of the at least two wireless power transmitting coils. 
     
     
       12. A wireless power transmitting device configured to wirelessly transmit power to a wireless power receiving device, comprising:
 a housing having no more than a first number of wireless power transmitting coils configured to transmit wireless power signals to the wireless power receiving device; 
 a connector having contacts configured to receive direct-current power from an external power port; and 
 a cable connected between the connector and the housing that has no more than a second number of wires, wherein the second number is less than the first number and wherein the cable is configured to carry alternating-current signals. 
 
     
     
       13. The wireless power transmitting device of  claim 12  further comprising:
 power harvesting circuitry in the housing. 
 
     
     
       14. The wireless power transmitting device of  claim 13  wherein the power harvesting circuitry is configured to receive the alternating-current signals over the cable and provide corresponding direct-current power. 
     
     
       15. The wireless power transmitting device of  claim 14  further comprising control circuitry in the housing that receives the direct-current power. 
     
     
       16. The wireless power transmitting device of  claim 15  further comprising:
 control circuitry in the connector that sends tone-encoded information to the control circuitry in the housing; and 
 switches in the housing that are controlled by the control circuitry in the housing based on the tone-encoded information. 
 
     
     
       17. The wireless power transmitting device of  claim 12  further comprising control circuitry in the connector configured to control switching circuitry in the housing to switch a selected subset of the wireless power transmitting coils into use to transmit the wireless power signals. 
     
     
       18. A wireless power transmitting device, comprising:
 a connector having contacts configured to mate with corresponding contacts in a port; 
 a housing having a magnet configured to mate with a magnet in a wireless power receiving device; 
 wireless power transmitting coils in the housing; 
 a cable with wires, wherein the cable has a first end coupled to the connector and a second end coupled to the housing; 
 power harvesting circuitry in the housing that receives impulses from the connector over the wires and that supplies corresponding direct-current power; and 
 control and switching circuitry in the housing that is powered by the direct-current power and that uses a subset of the wireless power transmitting coils to transmit wireless power signals. 
 
     
     
       19. The wireless power transmitting device of  claim 18  wherein the connector comprises a Universal Serial Bus connector.

Description:
This application is a continuation of U.S. patent application Ser. No. 16/503,194, filed Jul. 3, 2019, which claims the benefit of U.S. provisional patent application No. 62/840,274, filed Apr. 29, 2019, which are hereby incorporated by reference herein in their entireties. 
    
    
     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 power transmitting device such as a charging mat or charging puck wirelessly transmits power to a wireless power receiving device such as a portable electronic device. The portable electronic device has a coil and rectifier circuitry. The coil of the portable electronic device receives alternating-current wireless power signals from the wireless power transmitting device. The rectifier circuitry converts the received signals into direct-current power. 
     SUMMARY 
     A wireless power system has a wireless power transmitting device and a wireless power receiving device. The wireless power receiving device may be a wristwatch having a magnetic core with at least first and second wireless power receiving coils. The wireless power transmitting device may have a connector such as a Universal Serial Bus connector that is coupled to a puck housing with a three-wire cable. 
     The wireless power transmitting device has a set of wireless power transmitting coils in the puck housing. There may be, for example, four wireless power transmitting coils. A switch may be coupled in series with each of the four coils. When it is desired to transmit power to the wireless power receiving device, the wireless power receiving device is coupled to the puck housing using magnets. 
     Impulse response measurement circuitry in the transmitting device can probe the wireless power transmitting coils to determine which coils are overlapped by the wireless power receiving coils and are appropriate to use in transmitting wireless power. Control circuitry in the wireless power transmitting device may then activate a subset of the coils for use in transmitting the wireless power to the wireless power receiving coils. 
     The control circuitry of the wireless power transmitting device may have a main portion in the connector that uses a tone-based encoding scheme or other encoding scheme to transmit switch configuration commands to a secondary portion in the puck housing. The secondary portion of the control circuitry receives the switch configuration commands and controls the switches that are coupled to the four coils accordingly. In this way, the control circuitry selects a desired pair of the four coils to use in transmitting the wireless power signals to the overlapping wireless power receiving coils in the wireless power receiving device. 
     Alternating-current drive signals may be supplied to the selected pair of wireless power transmitting coils using switching circuitry in the connector that is controlled by the main portion of the control circuitry. 
    
    
     
       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 circuit diagram of wireless power transmitting and receiving circuitry in accordance with an embodiment. 
         FIG. 3  is a side view of an illustrative wireless power transmitting device such as a wireless charging puck and a corresponding wireless power receiving device such as a wrist watch with multiple wireless power receiving coils in accordance with an embodiment. 
         FIG. 4  is a circuit diagram of illustrative wireless power transmitting device circuitry for a wireless charging puck in accordance with an embodiment. 
         FIG. 5  is a graph showing signals associated with transmitting measurement impulses and measuring impulse responses in accordance with an embodiment. 
         FIG. 6  is a diagram of power harvesting circuitry for the puck portion of the wireless power transmitting device in accordance with an embodiment. 
         FIGS. 7, 8, 9, 10, 11, and 12  are diagrams showing six illustrative coil overlap scenarios and wireless power transmitting arrangements in a wireless charging puck having an array of four wireless power transmitting coils in accordance with an embodiment. 
         FIG. 13  is a flow chart of illustrative operations associated with using a wireless power transmitting device to transmit power to 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 puck. The wireless power transmitting device wirelessly transmits power to a wireless power receiving device such as a wristwatch or other electronic equipment. The wireless power receiving device uses power from the wireless power transmitting device for powering the device and for charging an internal battery. 
     The wireless power transmitting device interacts with the wireless power receiving device and obtains information on the characteristics of the wireless power receiving device. In some embodiments, the wireless power transmitting device has multiple power transmitting coils. In such embodiments, the wireless power transmitting device uses information from the wireless power receiving device and/or measurements made in the wireless power transmitting device to determine which coil or coils in the transmitting device are magnetically coupled to wireless power receiving devices. Coil selection is then performed in the wireless power transmitting device. Wireless power is transmitted from the wireless power transmitting device to the wireless power receiving device using selected coil(s) to charge a battery in the wireless power receiving device and/or to power other load circuitry. 
     The wireless power transmitting device has a cable with one end coupled to a connector such as a Universal Serial Bus (USB) connector for receiving power and another end coupled to a puck housing containing wireless power transmitting coils. The wireless power transmitting device has control circuitry that activates switches to select which coils in the puck housing are used to transmit wireless power to the wireless power receiving device, thereby helping to enhance wireless power transfer efficiency. The cable connector has a connector housing (e.g., a connector boot). The control circuitry may include a main controller (e.g., a main or a first control circuitry portion) in the connector (e.g., in the connector housing) and may include a secondary controller (e.g., an additional or a second control circuitry portion) in the puck housing. 
     The cable coupling the connector housing and puck housing may be a three-wire cable (e.g., a cable having more than two wires and fewer than four wires and having fewer wires than the number of coils in the puck housing). The main controller and secondary controller can communicate over a pair of the wires in the three-wire cable. Power harvesting circuitry may be provided in the puck housing. During initial measurement operations in which the main controller issues impulses to the coils, the power harvesting circuitry converts power from the impulses into direct-current (DC) power for powering the secondary controller. 
     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 power transmitting device that includes power adapter circuitry), may be a wireless charging puck or other device 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 puck having a cable with a connector that is adapted to plug into a device such as a power adapter or other electronic equipment with a USB connector port are sometimes described herein as an example. 
     Power receiving device  24  may be a portable electronic device such as a wristwatch or other electronic equipment. Power transmitting device  12  may be coupled to a wall outlet (e.g., an alternating current power source) and may use AC-DC converter to produce direct-current (DC) power and/or may have a battery for supplying power. In some embodiments, which are described herein as an example, AC-DC converter  14  is a stand-alone power converter or is incorporated into a laptop computer or other device with a connector port (e.g., a USB connector port). With this type of arrangement, device  12  is separate from the equipment that includes converter  14  and has a cable that plugs into the connector port to receive DC power from converter  14 . 
     The 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 switches such as 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 coils  36 . Coils  36  may be arranged in a planar coil array (e.g., in configurations in which device  12  is a wireless charging mat) or may be arranged to form a cluster of coils (e.g., in configurations in which device  12  is a wireless charging puck). In some arrangements, device  12  may have only a single coil. In other arrangements, device  12  may have multiple coils (e.g., two or more coils, four or more coils, six or more coils, 2-6 coils, fewer than 10 coils, etc.). An illustrative configuration for device  12  in which device  12  has four wireless power transmitting coils  36  is described herein as an example. 
     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 . Device  24  may have a single coil  48 , at least two coils  48 , at least three coils  48 , at least four coils  48 , or other suitable number of coils  48 . In an illustrative configuration, which may sometimes be described herein as an example, device  24  has at least two coils. These two (or more) coils overlap a subset (e.g., a pair) of the four coils  36  in device  12  and receive wireless signals from the overlapped coils. 
     When the alternating-current electromagnetic fields are received by coils  48 , corresponding alternating-current currents are induced in coils  48 . Rectifier circuitry such as rectifier circuitry  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 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 . For example, device  24  may include input-output devices  56  such as a display, touch sensor, communications circuits, audio components, sensors, light-emitting diode status indicators, other light-emitting and light detecting components, and other components and these components (which form a load for device  24 ) may be powered by the DC voltages produced by rectifier circuitry  50  (and/or DC voltages produced by battery  58 ). 
     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 . In-band transmissions between devices  12  and  24  may be performed using coils  36  and  48 . 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. 
     It is desirable for power transmitting device  12  and power receiving device  24  to be able to communicate information such as received power, states of charge, and so forth, to control wireless power transfer. However, the above-described technology need not involve the transmission of personally identifiable information in order to function. Out of an abundance of caution, it is noted that to the extent that any implementation of this charging technology involves the use of personally identifiable information, implementers should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     Control circuitry  16  has external object measurement circuitry  41  that may be used to detect external objects adjacent to 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). 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 ). During object detection and characterization operations, external object measurement circuitry  41  can be used to make measurements on coils  36  to determine whether any devices  24  are present on device  12 . 
     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 that can create impulses so that impulse responses can be measured to gather inductance information, Q-factor information, 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  (e.g., in the puck of device  12 ) may be adjusted by control circuitry  16  to switch each of coils  36  into use. As each coil  36  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 (e.g., so that this information can be used by device  24  and/or device  12 ). 
       FIG. 2  is a circuit diagram of illustrative wireless charging circuitry for system  8 . 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  70 . 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 (e.g., a pair of inverters  61  may produce output signals in phase or out of phase (e.g., 180° 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  70  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. 
       FIG. 3  is a cross-sectional side view of system  8  in an illustrative configuration in which wireless power transmitting device  12  is a wireless charging puck and in which wireless power receiving device  24  is a wristwatch (as an example). As shown in  FIG. 3 , device  12  has housing  90  (e.g., a disk-shaped puck housing formed form polymer, other dielectric material, and/or other materials). Cable  92  is coupled to housing  90  and provides power to coils  36 . Cable  92  may be, for example, a three-wire cable. One end of cable  92  may be pigtailed to housing  90 . The opposing end of cable  92  is terminated using connector  94 . Connector  94  has contacts (pins)  96  supported by connector housing  98 . Connector housing  98 , which may sometimes be referred to as a boot or connector boot, may be formed from polymer, metal, and/or other materials and may have an interior region configured to house electrical components (e.g., integrated circuits, discrete components such as transistors, printed circuits, etc.). Contacts  96  are configured to mate with corresponding pins in port  102  of external equipment such as device  100 . Device  100  may be a stand-alone power adapter, an electronic device such as a computer, or other equipment that provides DC power to connector  94  through port  102 . Port  102  may be, for example, a USB port. 
     Device  24  has a housing such as housing  104 . Housing  104  and device  24  have opposing front and rear faces such as front face F and rear face R. Housing  104  also has sidewall portions W. Wrist band  108  is coupled to sidewall portions W. Display  106  is formed on front face F of housing  104  and device  24  and lies in a plane that is perpendicular to the Z axis (e.g., a plane such as the X-Y plane of  FIG. 3  that is parallel to the planes including front face F and rear face R of housing  104 ). Device  24  and device  12  may have magnets (and/or magnetic material such as iron). For example, device  24  may have magnet  110  and device  12  may have mating magnet  112 . Magnets  110  and  112  attract each other and thereby hold devices  12  and  24  together during charging. In some embodiments, magnets  110  and  112  are located along central axis  116 , so that device  24  has the potential to rotate relative to device  12  about axis  116 . 
     The coils in devices  12  and/or  24  may have any suitable number of turns of wire (e.g., at least 2 turns, at least 10 turns, at least 30 turns, fewer than 200 turns, fewer than 100 turns, etc.). As shown in  FIG. 3 , coils  36  may be mounted in housing  90  of device  12  and coils  48  may be mounted in housing  104  of device  24 . In some configurations, the coils may be formed from turns of wire wrapped around cores made of iron, ferrite, or other magnetic material. 
     In the embodiment of  FIG. 3 , device  24  has coils  48  such as coils CA, CB, and CC. Two or more of coils  48  may be wound on a common magnetic core such as magnetic core  114 . Core  114  may have a horseshoe shape with vertical pillars for coils CA and CC and/or may have other suitable shapes. During operation, one, two, or three of coils CA, CB, and CC are used to receive wireless power that is being transmitted by wireless power transmitting coils  36 . Coils  36  are arranged in an array of four coils  36  surrounding central axis  116  or other suitable pattern. Depending on the relative rotational orientation of devices  24  and  12  about axis  116 , different subsets of coils  36  are used in transmitting wireless power. For example, in a first orientation, a first pair of the four coils  36  in device  12  can be used and in a second orientation, a second pair of the four coils  36  in device  12  can be used. The relative phase of the drive signals applied to the coils  36  in the selected pair can also be adjusted to ensure satisfactory power transfer to coils  48  (e.g., the relative phase of the drive signals applied to a pair of selected transmitting coils  36  can be adjusted so that the drive signals are in phase or 180° out of phase with respect to each other). 
     When device  12  is first coupled to device  24 , device  12  may perform measurements using measurement circuitry  41 . For example, control circuitry  16  may use impulse response measurement circuitry in measurement circuitry  41  to determine which of coils  36  is overlapped by coils  48  such as coils CA and CC at opposing ends of core  114 . In response to determining that a first of coils  36  is overlapped by coil CA and that a second of coils  36  is overlapped by coil CC, device  12  can use the first and second of coils  36  in transmitting wireless power to device  24 . 
     A diagram of device  12  showing illustrative circuitry that may be used to select desired coils  36  for transmitting wireless power to device  24  is shown in  FIG. 4 . 
     As shown in  FIG. 4 , device  12  has a connector such as connector  24  that is coupled to puck housing  90  by three-wire cable  92 . Connector  24  may be, for example, a Universal Serial Bus (USB) connector. Connector  24  has contacts  96  such as positive contact  96 P and ground contact  96 G (and/or other contacts) and is plugged into a power port in external electronic equipment to receive direct-current (DC) power (e.g., a DC voltage) across contacts  96 P and  96 G. Cable  92  conveys power and control signals from connector  94  to the circuitry in puck housing  92 . 
     Control circuitry  16  ( FIG. 1 ) may include a first control circuitry portion such as main controller  16 M and a second control circuitry portion such as secondary controller  16 S. Switches T 1 , T 2 , T 3 , T 4 , SWA, SWB, SWC, and SWD, which may sometimes be referred to as forming part of control circuitry  16 , may be controlled by control signals that are asserted and deasserted by main controller  16 M and/or by secondary controller  16 S. Main controller  16 M is formed in connector housing  98 . Secondary controller  16 S is formed in puck housing  90 . During operation, main controller  16 M may transmit control signals to secondary controller  16 S over signal paths (e.g., signal paths P 1  and P 2  and ground path G) in cable  92 . 
     Switching circuitry such as switches T 1 , T 2 , T 3 , and T 4  (e.g., transistors having gates that receive control signals from control circuitry such as main controller  16 M) may form inverter circuitry  61  ( FIG. 2 ) and may be controlled (e.g., turned on and off repeatedly) to produce alternating-current drive signals for coils  36  from the direct-current (DC) voltage supplied across contacts  96 P and  96 G. The alternating-current drive signals are provided to coils  36  through capacitors  70  and cable  92 . Coils  36  can be formed in an array in puck housing  90 . As an example, coils  36  may be arranged in a circle so that all four of coils  36  are able to transmit and/or receive magnetic fields through the upper surface of housing  90 . 
     Secondary controller  16 S can be coupled to signal paths P 1 , P 2 , and G of cable  92 . During operation, main controller  16 M and secondary controller  16 S may transmit and/or receive signals using any suitable communications scheme (e.g., using bidirectional communications or unidirectional communications). Digital data (e.g., isolated control bits, packets of digital data, etc.) may be transmitted. The digital data may be encoded using tone encoding and/or other suitable encoding techniques. 
     As an example, main controller  16 M may send instructions to secondary controller  16 S to direct secondary controller  16 S to activate selected switches SWA, SWB, SWC, and SWD (e.g., a subset of these switches such as a pair of these switches) and thereby activate selected coils  36  (e.g., a pair of coils  36 ) for use in transmitting wireless signals to device  24 . In response, secondary controller  16 S may issue local control signals (e.g., controller  16 S may assert and/or deassert control signals on transistor gates or other control terminals associated with switching circuitry in puck housing  90  such as switches SWA, SWB, SWC, and SWD). 
     When switch SWA is open, a first of coils  36  (coil C 1 ) is switched out of use. When switch SWA is closed, coil C 1  is switched into use and can transmit wireless signals in response to the AC drive signals received using signal paths P 1  and G. When switch SWB is open, a second of coils  36  (coil C 2 ) is switched out of use. When switch SWB is closed, coil C 2  is switched into use and can transmit wireless signals in response to the AC drive signals received using signal paths P 1  and G. When switch SWC is open, a third of coils  36  (coil C 3 ) is switched out of use. When switch SWC is closed, coil C 3  is switched into use and can transmit wireless signals in response to the AC drive signals received using signal paths P 2  and G. When switch SWD is open, a fourth of coils  36  (coil C 4 ) is switched out of use. When switch SWD is closed, coil C 4  is switched into use and can transmit wireless signals in response to the AC drive signals received using signal paths P 2  and G. Coils  36  can have any suitable winding senses (clockwise, counterclockwise). In the example of  FIG. 4 , coil C 1  is wound clockwise (CW), coil C 2  is wound counterclockwise (CCW), coil C 3  is wound counterclockwise (CCW), and coil C 4  is wound clockwise (CW). 
     During initial operation, control circuitry  16  uses measurement circuitry  41  (e.g., impulse response measurement circuitry) to drive impulses (see, e.g., square waves  120  of  FIG. 5 ) onto coils  36  while measuring and analyzing corresponding impulse responses in coils  36  (e.g., to analyze the frequency, decay envelope, and other properties of impulse response signals  122  in coils  36 ). Using these measurements, control circuitry  16  can determine which of the four coils  36  are magnetically coupled to coils  48  in device  24  (e.g., so that device  12  can determine which coils  36  are overlapped by coils CA and CC and should therefore be used in transmitting wireless power signals). Impulses  120  may be pulses with any suitable duration. For example, impulses  120  may have durations less than 10 ms, less than 1 ms, less than 100 microseconds, less than 10 microseconds, less than 1 microsecond, more than 1 microsecond, more than 5 microseconds, more than 25 microseconds, etc. 
     The process of sending AC measurement signals such as impulses  120  over cable  92  from connector  94  supplies power to puck  90 . This power may be harvested by power harvesting circuitry in puck  90  such as illustrative power harvesting circuitry  136  of  FIG. 6 . As shown in  FIG. 6 , power harvesting circuitry  136  of  FIG. 6  includes peak detector circuits  124  that receive impulses  120  on lines P 1  and P 2 , respectively. Each peak detector circuit  124  has a diode  128 , resistors  130  and  134 , and a capacitor  132 . During each impulse  120 , diode  128  turns on and capacitor  132  charges, which creates a voltage at the input of voltage regulator  126 . Resistor  130  forms an RC filter with capacitor  132 . Resistor  134  helps the voltage at the input of voltage regulator  126  return to ground potential when voltage regulator  126  is off. 
     The output of peak detector circuits  124  is converted to a desired DC voltage using voltage regulator  126  and used to power secondary controller  16 S. In this way, secondary controller  16 S can be powered by harvesting power from impulses (pings)  120  and can operate (e.g., to open and close desired switches among switches SWA, SWB, SWC, and SWD) without incorporating additional (e.g., separate) power supply paths in cable  92 . This helps reduce the size of cable  92 . 
     Any suitable communications protocol(s) may be used to support communications between main controller  16 M and secondary controller  16 S. With an illustrative configuration, secondary controller  16 S monitors signal paths P 1  and P 2  for incoming signals from main controller  16 M. When main controller  16 M desires to send commands to secondary controller  168 , main controller  16 M controls the states of switches (transistors) T 1 , T 2 , T 3 , and T 4 . Switches T 1 , T 2 , T 3 , and T 4  are configured to form a full-bridge driver circuitry that includes half-bridge driver circuitry HB 1  (switches T 1  and T 2 ) and half-bridge driver circuitry HB 2  (switches T 3  and T 4 ). When main controller  16 M desires to direct secondary controller  16 S to close switch SWA, main controller  16 M may, as an example, use half-bridge driver circuitry HB 1  to supply a 100 kHz tone to path P 1 . A different tone (e.g., a 150 kHz tone) may be supplied on path P 1  when main controller  16 M desires to direct secondary controller  16 S to close switch SWB. Switch SWC may be closed by using main controller  16 M to send a 100 kHz tone to secondary controller  16 S on path P 2 . Switch SWD may be closed by sending a 150 kHz tone to secondary controller  16 S on path P 2 . 
     As this example demonstrates, communications between controllers  16 M and  16 S may involve path-based and tone-based encoding. Other encoding schemes may be used if desired. For example, information may be conveyed by adjusting the duty cycle of pulses  120  (e.g., duty-cycle encoding may be used to inform controller  16 S of which switches to close by, for example, sending pulses  120  with a 10% duty cycle to instruct controller  16 S to control one switch and sending pulses  120  with a 20% duty cycle to instruct controller  16 S to close a different switch, etc.). If desired, tone-based encoding schemes may use tones of different frequencies than 100 kHz and 150 kHz, non-tone signaling schemes may be used (e.g., DC-encoded voltages may be conveyed over cable  92  by, e.g., using a 5 V to direct controller  16 S to close one switch and using a 6 V to direct controller  16 S to close a different switch), and/or other suitable communications schemes may be used. Communications may be unidirectional (controller  16 M sends instructions such as switch configuration instructions to controller  16 S) and/or bidirectional (e.g., to allow controller  16 S to handshake and/or send information to controller  16 M). 
     When it is desired to transmit power wirelessly from device  12  to device  24 , housing  104  is coupled to housing  90  using magnets  110  and  112 . This places device  24  and housing  104  in a particular rotational orientation about axis  116  with respect to device  12  and housing  90 . As a result, core  114  and coils CA and CC will be oriented in a particular rotational orientation about axis  116  with respect to transmitting coils  36 . For example, coils CA and CC may overlap coils C 1  and C 2  while not overlapping coils C 3  and C 4 . Once housings  104  and  90  are coupled to each other, controller  16 M can detect which coils  36  are overlapped by coils CA and CC using impulse response measurements. After determining (in this example) that coils C 1  and C 2  in puck housing  90  are being overlapped and should therefore be used in transmitting wireless power to device  24 , controller  16 M sends control signals to secondary controller  168  that direct controller  168  to close switches SWA and SWB while opening switches SWC and SWD. This inactivates unused coils C 3  and C 4  and activates coils C 1  and C 2  so that wireless power is transmitted to coils CA and CC by coils C 1  and C 2 . 
     The relative phase of the drive signals for coils C 1  and C 2  is determined by the winding sense for coils C 1 , C 2 , CA, and CC. For example, coil C 1  can be configured to create a “north” magnetic field while coil C 2  creates a “south” magnetic field, which allows magnetic field to travel from coil C 1  to overlapping coil CA, through core  114  (and past optional coil CB, which can be used to help extract power from the transmitted signal), then out through coil CC into coil C 2 . If the winding senses of the selected subset of coils  36  to be used for power transmission are not as desired (e.g., if a coil has a clockwise winding sense when a counterclockwise sense is desired), controller  16 M can adjust the phase of the control signals applied to switches T 1 , T 2 , T 3 , and T 4  in half-bridge driver circuitry HB 1  and/or HB 2  (e.g., to flip the relative phase of the AC drive signal supplied to a first active coil by 180° or other suitable amount with respect to another active coil). 
       FIGS. 7, 8, 9, 10, 11, and 12  show six possible relative orientations between coils CA and CB in device  24  (coils  48 ) and underlying coils C 1 , C 2 , C 3 , and C 4  (coils  36 ) in device  12 . 
     In the example of  FIG. 7 , coil CA overlaps coil C 1  and coil CC overlaps coil C 2 . Coils C 1  and C 2  are therefore activated by closing switches SWA and SWB and coils C 3  and C 4  are switched off by opening switches SWC and SWD. In the present example, the winding senses of coils C 1  and C 2  are opposite so that coil C 1  produces magnetic field with a first orientation (e.g., north N) while coil C 2  produces magnetic field with an opposite second orientation (e.g., south S), which is appropriate (in this example) for supplying power to coils CA and CC (and, if desired, CB) on core  114 ). Accordingly, the AC drive circuitry of device  12  in connector  94  may be used to drive coils C 1  and C 2  in phase while transmitting wireless power from coils C 1  and C 2  to coils CA and CC. 
     In the example of  FIG. 8 , coils C 3  and C 4  may be activated and driven in phase to transmit power to overlapping coils CA and CC, whereas coils C 1  and C 2  may be turned off. 
     In the example of  FIG. 9 , the winding sense of coils C 1  and C 3  are such that coil C 1  and coil C 3  produce magnetic fields of the same orientation unless driven out of phase. Accordingly to couple effectively with overlapping coils CA and CC, coils C 1  and C 3  can be supplied with AC drive signals that are 180° out of phase. Coils C 2  and C 4  can be switched out of use by directing secondary controller  16 S to place switches SWB and SWD in their open states. 
     In the example of  FIG. 10 , 180° out-of-phase drive signals are applied to coils C 2  and C 4  to supply wireless power to overlapping coils CA and CC. Coils C 1  and C 3  are not overlapped by coils in device  24  and are therefore switched out of use. 
     In the example of  FIG. 11 , coil CA overlaps coil C 1  and coil CC overlaps coil C 4 . Accordingly, coils C 1  and C 4  are switched into use and coils C 2  and C 3  are switched out of use. Coils C 1  and C 4  are driven in phase (in this example). 
     In the example of  FIG. 12 , coil CA overlaps coil C 2  and coil CC overlaps coil C 3 . Coils C 2  and C 3  can therefore be switched into use and coils C 1  and C 4  can be switched out of use. Coils C 2  and C 3  can be driven in phase during wireless power transmission. 
     Illustrative operations involved in using wireless power transmitting device  12  to transmit wireless power to wireless power receiving device  24  are shown in  FIG. 13 . 
     During the operations of block  150 , control circuitry  16  activates each of coils  36  in turn and uses the activated coil to measure whether one of coils  48  is overlapping that coil  36  and is therefore ready to receive wireless power. With an illustrative configuration, main controller  16 M, which is used in controlling switches T 1 , T 2 , T 3 , and T 4 , sends impulses  120  over cable  92  while directing secondary controller  16 S to switch on each of coils  36  in sequence (while turning off all remaining coils  36 ). The impulse responses produced by applying impulses  120  can be evaluated by controller  16 M to determine the inductance of each of coils  36  and thereby determine which of coils  36  are overlapped by coils  48  (e.g., coil CA or coil CC and the associated portions of magnetic material in core  114  on which the coils are wound). Power harvested from the impulses is used in powering secondary controller  16 S. If desired, in addition to or instead of using impulse response measurements to evaluate overlap and magnetic coupling between coils  48  and coils  36 , overlap and coupling can be evaluated by using each coil  36  to momentarily transmit wireless power signals and observing the results of these power transfer operations between device  12  and device  24  (e.g., using measurement circuitry  41  and/or  43 , etc.). 
     After using impulse response measurements or other measurements indicative of magnetic coupling between each of wireless power transmitting coils  36  and each of wireless power receiving coils  48 , control circuitry  16  (e.g., main controller  16 M) may, during the operations of block  152 , select a subset of transmitting coils to be used such as the best two coils  36  (e.g., the two coils  36  with the highest coupling to coils  48  or the two coils  36  that satisfy other predetermined coil selection criteria). Main controller  16 M can then send control signals to secondary controller  16 S that direct secondary controller  16 S to activate corresponding switches in puck housing  90  to activate these two coils  36 . For example, in the scenario of  FIG. 7 , coils C 1  and C 2  are turned on and this setting is locked into place by secondary controller  16 S in the absence of additional commands from main controller  16 M. 
     During the operations of block  154 , main controller  16  uses appropriate switches in connector  94  (see, e.g., switches T 1 , T 2 , T 3 , and T 4 ) to supply AC drive signals of appropriate phase (e.g., in phase or 180° out of phase) to the coils activated during the operations of block  152 . Main controller  16 M may, as an example, operate half-bridge circuitry HB 1  and/or half-bridge circuitry HB 2  in or out of phase, as appropriate. 
     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: 20200729
Publication Date: 20220614
Grant Date: 20220614
Priority Date: 20190429
Inventors: REN, SAINING
LEUNG, HO FAI
CHEN, LIANG
Assignee: APPLE INC
CPC Classifications: [{"code": "H02J50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/402", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0044", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/00034", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/402", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0042", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0042", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/80", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/0037", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/0075", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/402", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/24", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 81944253