Communication between devices in a wireless charging system

Abstract

A wireless power system can include devices that transmit and / or receive wireless power. Devices in the wireless power system can exchange packets to facilitate the communication of various types of data. The data can be transmitted using in-band communication. The devices can use locally assigned addresses to communicate with any other device in the wireless power system. During a network discovery process, a list of devices can be exchanged between the devices until each device has a complete list of all other devices in the network. The list of all other devices in the network can include respective addresses of each device based on a topology of the network. The locally assigned address can identify an inductive coupling path from a first device to a second device, including at least one intervening device, even if the first device is not inductively coupled to the second device.

Description

[0001] This application claims priority to U.S. Patent Application No. 17 / 100,123, filed November 20, 2020, U.S. Provisional Patent Application No. 63 / 030,018, filed May 26, 2020, and U.S. Provisional Patent Application No. 63 / 030,027, filed May 26, 2020, which are hereby incorporated by reference in their entirety. TECHNICAL FIELD

[0002] The present disclosure relates generally to power systems, and more specifically, to wireless power systems for charging electronic devices. BACKGROUND

[0003] In a wireless charging system, a wireless power transmitting device such as a charging pad transmits power wirelessly to a wireless power receiving device such as a portable electronic device. The wireless power receiving device has a coil and a rectifier circuit. The coil receives an alternating wireless power signal from the wireless charging pad. The rectifier circuit converts the received signal to direct current power. SUMMARY

[0004] A wireless power system can include one or more wireless power transmitting devices, one or more wireless power receiving devices, and one or more wireless power transmitting and receiving devices. The wireless power transmitting device can include a coil and a wireless power transmitting circuit coupled to the coil. The wireless power transmitting circuit can be configured to transmit a wireless power signal with the coil. The wireless power receiving device can include a coil configured to receive a wireless power signal from the wireless power transmitting device and a rectifier circuit configured to convert the wireless power signal to direct current power. The wireless power transmitting and receiving device can include at least one coil, and both a wireless power transmitting circuit and a wireless power receiving circuit.

[0005] Devices in a wireless power system can exchange packets to facilitate the communication of various types of data. Authentication data, firmware data, command data, configuration data, and / or power data can be transmitted between devices in a wireless power system. Data can be transmitted using in-band communication (e.g., amplitude shift keying modulation or frequency shift keying modulation).

[0006] The device can use the locally assigned address to communicate with any other device in the wireless power system. The locally assigned address can identify an inductive coupling path from the first device to a second device, including at least one intervening device, even if the first device is not inductively coupled to the second device. Thus, the first device can communicate with the second device using in-band communication packets that are relayed by the at least one intervening device. Each device in the wireless power system can maintain a list of all other devices in the network. Each other device in the network can be assigned a respective address that indicates an inductive coupling path to that device. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 is a schematic diagram of an exemplary wireless power system in accordance with an embodiment.

[0008] Figure 2 is a circuit diagram of exemplary wireless power transmit and receive circuitry in accordance with an embodiment.

[0009] Figure 3A is a diagram of a wireless power system including a power transmitting device, a power transmitting and receiving device, and three power receiving devices in accordance with an embodiment.

[0010] Figure 3B is a network diagram of a wireless power system corresponding to Figure 3A in accordance with an embodiment.

[0011] Figure 4A is a diagram of a wireless power system including a power transmitting device, a power transmitting and receiving device, and two power receiving devices in accordance with an embodiment.

[0012] Figure 4B is a network diagram of a wireless power system corresponding to Figure 4A in accordance with an embodiment.

[0013] Figure 5 is a flow diagram illustrating exemplary operations involving a network discovery procedure for a wireless power system in accordance with an embodiment.

[0014] Figures 6A-6E is a diagram illustrating various steps of a network discovery procedure for Figure 5 in accordance with an embodiment.

[0015] Figure 7 is a diagram of exemplary packets that can be used for communication in a wireless power system in accordance with an embodiment.

[0016] Figure 8is an illustration showing an exemplary packet structure showing a list of devices that can be exchanged between devices in a wireless power system, according to one embodiment.

[0017] Figure 9 is an illustration showing an exemplary packet header that can be used to identify a stream number, a source address, and a destination address, according to one embodiment.

[0018] Figure 10 is an illustration showing addresses that can be used in packets in a wireless power system, according to one embodiment.

[0019] Figure 11 is a flow diagram showing exemplary operations involving sending packets between devices in a wireless power system, according to one embodiment.

[0020] Figures 12A-12C is an illustration showing various steps of a packet delivery process of Figure 11 , according to one embodiment.

[0021] Figure 13 is an illustration showing an exemplary packet exchange that can be used by a first device to open a data stream with a second device to which it is not inductively coupled, according to one embodiment.

[0022] Figure 14 is an illustration showing an exemplary packet exchange that can be used by a first device to send data to a second device to which it is not inductively coupled, according to one embodiment. DETAILED DESCRIPTION

[0023] A wireless power system can include one or more electronic devices that transmit wireless power, one or more electronic devices that receive wireless power, and one or more electronic devices that both transmit and receive wireless power. The wireless power transmitting devices can be, for example, wireless charging pads or wireless charging mats. The wireless power receiving devices can be, for example, devices such as wristwatches, cellular telephones, tablet computers, laptop computers, or other electronic equipment. The wireless power transmitting and receiving devices can be electronic device housings (e.g., the housing of a cellular telephone) or other types of electronic devices. The wireless power transmitting devices can wirelessly transmit power to the wireless power receiving devices. The wireless power receiving devices use the power from the wireless power transmitting devices to power the devices and to charge internal batteries.

[0024] Wireless power is transmitted from the wireless power transmitting devices to the wireless power receiving devices using one or more wireless power transmitting coils. The wireless power receiving devices have one or more wireless power receiving coils that are coupled to a rectifier circuit that converts the received wireless power signal to direct current power.

[0025] Figure 1 An exemplary wireless power system (wireless charging system) is shown. For example... Figure 1 As shown, the wireless power system 8 may include one or more wireless power transmitting devices such as wireless power transmitting device 12, one or more wireless power receiving devices such as wireless power receiving device 24, and one or more electronic devices such as wireless power transmitting and receiving device 18 capable of simultaneously transmitting and receiving wireless power. It should be understood that one or more of each type of device may be present in the wireless power system at any given time, with devices being added to and removed from the system in a fluid manner. The functionality of power transmitting and receiving device 18 may vary depending on the system's arrangement at a given time. In some scenarios, the power transmitting and receiving devices may only transmit power, in some scenarios they may only receive power, and in some scenarios they may both transmit and receive power simultaneously. In some scenarios, power transmitting device 12 may transmit power directly to power receiving device 24. In other scenarios, power transmitting device 12 may transmit power to power transmitting and receiving device 18, which then transmits power to power receiving device 24. The functionality of each device and the inductive coupling between each device within the system may be updated as devices are added to and removed from the system.

[0026] Wireless power transmitting device 12 includes control circuitry 16. Wireless power receiving device 24 includes control circuitry 30. Wireless power transmitting and receiving device 18 includes control circuitry 78. Control circuitry in system 8, such as control circuitry 16, control circuitry 30, and control circuitry 78, is used to control the operation of system 8. This control circuitry may include processing circuitry associated with a microprocessor, power management unit, baseband processor, digital signal processor, microcontroller, and / or application-specific integrated circuit (ASIC) having processing circuitry. The processing circuitry implements desired control and communication characteristics in devices 12, 18, and 24. For example, the processing circuitry may be used to select coils, determine power transmission levels, process sensor data and other data to detect intrusive objects and perform other tasks, process user input, handle negotiations between devices 12, 18, and 24, transmit and receive in-band and out-of-band data, perform measurements, and otherwise control the operation of system 8.

[0027] The control circuit in system 8 can 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 a non-transitory computer-readable storage medium (e.g., a tangible computer-readable storage medium) in control circuit 8. Software code can sometimes be referred to as software, data, program instructions, instructions, or code. The non-transitory computer-readable storage medium can include non-volatile memory such as non-volatile random access memory (NVRAM), one or more hard disk drives (e.g., magnetic disk drives or solid state drives), one or more removable flash drives, or other removable media, etc. The software stored on the non-transitory computer-readable storage medium can be executed on processing circuitry of control circuit 16, 30, and / or 78. The processing circuitry can include a special-purpose integrated circuit with the processing circuitry, one or more microprocessors, central processing units (CPUs), or other processing circuitry.

[0028] Power transmitting device 12 can be a standalone power adapter (e.g., a wireless charging mat or charging dock that includes power adapter circuitry), can be a wireless charging mat or dock that is coupled to a power adapter or other equipment through a cable, can be a portable device, can be equipment that has been incorporated into furniture, a vehicle, or other system, can be a removable battery pack, or can be other wireless power transfer equipment. Exemplary configurations in which wireless power transmitting device 12 is a wireless charging mat or wireless charging pad are sometimes described herein as examples.

[0029] Power receiving device 24 can be a portable electronic device such as a wristwatch, a cellular telephone, a laptop computer, a tablet computer, an accessory such as earbuds, or other electronic equipment. Power transmitting device 12 can be coupled to a wall outlet (e.g., an alternating current power source), can have a battery for supplying power, and / or can have another power source. Power transmitting device 12 can have an alternating current (AC)-direct current (DC) power converter such as AC-DC power converter 14 for converting AC power from a wall outlet or other power source to DC power. The DC power can be used to power control circuit 16. During operation, a controller in control circuit 16 uses power transmitting circuit 52 to transmit wireless power to power receiving circuit 54 of device 24. For simplicity, examples are described herein in which power transmitting device 12 transmits wireless power to power receiving device 24. However, it should be understood that power transmitting and receiving devices 18 can substitute for one or both of the power transmitting and power receiving devices during wireless power transfer operations.

[0030] The power transmitting circuit 52 can have a switching circuit (e.g., an inverter circuit 61 formed from transistors) that is turned on or off based on control signals provided by the control circuit 16 to form an AC current signal through one or more wireless power transmitting coils, such as the wireless power transmitting coil 36. These coil drive signals cause the coil 36 to transmit wireless power. The coil 36 can be arranged as a planar coil array, or can be arranged to form a cluster of coils. In some arrangements, the device 12 (e.g., a charging pad, a charging cradle, etc.) can have only a single coil. In other arrangements, the wireless charging device can have multiple coils (e.g., two or more coils, 5-10 coils, at least 10 coils, 10-30 coils, fewer than 35 coils, fewer than 25 coils, or other suitable number of coils).

[0031] When the AC current passes through the one or more coils 36, alternating electromagnetic (e.g., magnetic) fields (the wireless power signal 44) are produced that are received by one or more corresponding receiver coils, such as the coil 48 in the power receiving device 24. In other words, one or more of the coils 36 are inductively coupled to one or more of the coils 48. The device 24 can 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. When the alternating electromagnetic fields are received by the coil 48, a corresponding alternating current is induced in the coil 48. The AC signal used to transmit the wireless power can have any suitable frequency (e.g., 100 kHz-250 kHz, etc.). A rectifier circuit, such as the rectifier circuit 50 (which includes rectifying components, such as synchronous rectification metal oxide semiconductor transistors arranged in a bridge network), converts the AC signal received from the one or more coils 48 (the received alternating current signal associated with the electromagnetic signal 44) to a DC voltage signal for powering the device 24.

[0032] The DC voltage generated by the rectifier circuit 50 (sometimes referred to as the rectifier output voltage Vrect) can be used to charge a battery such as the battery 58, and can be used to power other components in the device 24. For example, the device 24 can include an input-output device 56. The input-output device 56 can include input devices for gathering user input and / or making environmental measurements, and can include output devices for providing output to a user. For example, the input-output device 56 can include a display for creating visual output, a speaker for presenting output as an audio signal, light-emitting diode status indicator lights and other light-emitting components for emitting light that provides status information and / or other information to a user, haptic devices for generating vibrations and other haptic output, and / or other output devices. The input-output device 56 can also include sensors for gathering input from a user and / or for making measurements of the surrounding environment of the system 8. Exemplary sensors that can be included in the input-output device 56 include three-dimensional sensors (e.g., a three-dimensional image sensor such as a structured light sensor that emits a beam of light and uses a two-dimensional digital image sensor to gather image data for a three-dimensional image from a light spot created when the beam of light illuminates a target; a binocular three-dimensional image sensor that uses two or more cameras in a binocular imaging arrangement to gather three-dimensional images; a three-dimensional laser radar (light detection and ranging) sensor; a three-dimensional radio frequency sensor; or other sensors that gather three-dimensional image data), cameras (e.g., infrared and / or visible light cameras with corresponding infrared and / or visible digital image sensors, and / or ultraviolet light cameras), gaze tracking sensors (e.g., gaze tracking systems based on image sensors and, if desired, light sources that emit one or more beams of light, where the image sensor is used to track the one or more beams of light after they are reflected by a user’s eyes), touch sensors, buttons, capacitive proximity sensors, light-based (optical) proximity sensors such as infrared proximity sensors, other proximity sensors, force sensors, sensors such as switch-based contact sensors, gas sensors, pressure sensors, humidity sensors, magnetic sensors, audio sensors (microphones), ambient light sensors, optical sensors for making spectral and other measurements of target objects (e.g., by emitting light and measuring reflected light), microphones for gathering voice commands and other audio input, distance sensors, motion, location, and / or orientation sensors configured to gather information about motion, location, and / or orientation (e.g., accelerometers, gyroscopes, compasses, and / or inertial measurement units that include all of these sensors or a subset of one or two of these sensors), sensors such as buttons that detect button press inputs, joysticks with sensors that detect joystick motion, keyboards, and / or other sensors. The device 12 can optionally have one or more input-output devices 70 (e.g., input devices and / or output devices of the types described in connection with the input-output device 56).Device 18 can optionally have one or more input-output devices 92 (e.g., input devices and / or output devices of the type described in connection with input-output devices 56).

[0033] Device 12, device 18, and / or device 24 can use in-band or out-of-band communication for wireless communication. Device 12 may, for example, have wireless transceiver circuitry 40 that uses an antenna to wirelessly transmit out-of-band signals (e.g., to device 18 or device 24). Wireless transceiver circuitry 40 can be used to wirelessly receive out-of-band signals from device 18 or 24 using an antenna. Device 24 can have wireless transceiver circuitry 46 that transmits out-of-band signals. Receiver circuitry in wireless transceiver 46 can use an antenna to receive out-of-band signals. Device 18 can have wireless transceiver circuitry 80 that transmits out-of-band signals. Receiver circuitry in wireless transceiver 80 can use an antenna to receive out-of-band signals. Wireless transceiver circuitry 40, 46, and 80 can also be used for in-band transmission between devices 12, 24, and 18 using coils 36, 48, and 90.

[0034] Frequency shift keying (FSK) and / or amplitude shift keying (ASK) can be used to communicate in-band data between devices 12, 18, and 24. During these FSK and ASK transmissions, power can be wirelessly transmitted.

[0035] It is desirable for power transmitting device 12, power transmitting and receiving device 18, and power receiving device 24 to be able to communicate information such as received power, battery charge status, etc. to control wireless power transfer. However, the above-described techniques can function without involving the transmission of personally identifiable information. With due caution, it is noted that to the extent that any implementation of this charging technology involves the use of personally identifiable information, the implementer 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, the users' data should be managed and handled in a manner that minimizes the potential for unauthorized or unauthorized access or use, and the nature of authorized use should be apparent to the users.

[0036] The control circuit 16 has an external object measurement circuit 41 that can be used to detect external objects on the charging surface of the housing of the device 12 (e.g., on top of a charging pad, or if desired, to detect objects adjacent to the coupling surface of a charging cradle). The housing of the device 12 can have polymeric walls, other dielectric walls, metallic structures, fabric, and / or other housing wall structures that enclose the coil 36 and other circuitry of the device 12. The charging surface can be formed by a flat outer surface of the upper housing wall of the device 12 or can have other shapes (e.g., concave or convex, etc.). In arrangements where the device 12 forms a charging puck, the charging puck can have a surface shape that fits the shape of the device 24. If desired, the charging puck or other device 12 can have a magnet that removably attaches the device 12 to the device 24 (e.g., so that the coil 48 is aligned with the coil 36 during wireless charging).

[0037] The circuit 41 can detect foreign objects such as coils, paperclips, and other metallic objects, and can detect the presence of a wireless power receiving device 24 (e.g., the circuit 41 can detect the presence of one or more coils 48 and / or a magnet core material associated with the coil 48). During object detection and characterization operations, the external object (foreign object) measurement circuit 41 can be used to make measurements of the coil 36 such as Q-factor measurements, resonant frequency measurements, and / or inductance measurements that can be indicative of whether a coil 48 is present and / or whether a foreign object such as a coin or paperclip is present. The measurement circuit can also be used to make sensor measurements using a capacitive sensor, can be used to make temperature measurements, and / or can be used in other ways to gather information indicative of whether a foreign object or other external object (e.g., the device 18 or 24) is present on the device 12.

[0038] In some configurations, the control circuit of the device 12 (e.g., the circuit 41 and / or other control circuit 16) can implement a power counting approach to foreign object detection. With this approach, the device 12 receives information from the device 24 (e.g., via in-band communication) that indicates the amount of power that the device 24 is receiving wirelessly (e.g., 4.5 W). The device 12 knows how much power is being sent (e.g., 5.0 W) (e.g., because the device 12 knows the magnitude of the signal used to drive the coil 36 from the inverter 61). By comparing the sent power (e.g., 5.0 W) to the received power (e.g., 4.5 W), the device 12 can determine whether wireless power is being dissipated due to eddy currents flowing in a foreign object. If the dissipated power (e.g., 0.5 W in this example) is greater than a predetermined threshold amount, or if the efficiency of the wireless power transfer process is lower than expected, the device 12 can conclude that a foreign object is present. Power counting techniques such as these can be used in conjunction with capacitive sensing foreign object detection techniques and / or other external object measurement operations performed using the circuit 41.

[0039] In some implementations, the measurement circuit 41 of the control circuit 16 includes signal generator circuitry (e.g., an oscillator circuit to generate an AC probe signal at one or more probe frequencies; a pulse generator that can produce pulses such that a pulse response can be measured) and / or uses transmission of the wireless power signal from the device 12 to energize the coils in the system 8. The circuit 41 can also include circuitry to measure the response of the system 8 (e.g., an analog-to-digital converter circuit, filters, analog combiners, digital processing circuitry, etc.).

[0040] The power transmitting and receiving device 18 can be a wireless charging pad or charging puck coupled by a cable to a power adapter or other equipment, can be equipment that has been incorporated into furniture, a vehicle, or other system, can be a removable battery case, can be a portable electronic device such as a wristwatch, a cellular telephone, a laptop computer, a tablet computer, an accessory such as earbuds, or other electronic equipment. The power transmitting and receiving device 18 is capable of simultaneously transmitting and receiving wireless power. Thus, the power transmitting and receiving device 18 can include power transmitting components, similar to the power transmitting device 12. The power transmitting and receiving device 18 can also include power receiving components, similar to the power receiving device 24.

[0041] The power transmitting and receiving device 18 can have an alternating current (AC) to direct current (DC) power converter such as an AC-DC power converter 96 for converting AC power from a wall outlet or other power source to DC power. The DC power can be used to power the control circuit 78. The control circuit 78 includes wireless transceiver circuitry 80 for in-band communication (using the coil 90) and out-of-band communication (using an antenna). The control circuit 78 can also optionally include a measurement circuit 82 (e.g., a measurement circuit of the type described in connection with the measurement circuit 41).

[0042] The wireless power circuit 84 in the device 18 can include both an inverter 86 and a rectifier 88. The inverter circuit 86 (e.g., formed from transistors) can be turned on and off based on control signals provided by the control circuit 78 to form an AC current signal through one or more coils such as the coil 90. These coil drive signals cause the coil 90 to transmit wireless power. The coil 90 can be arranged as a planar coil array, or can be arranged to form a cluster of coils. In some arrangements, the device 18 can have only a single coil. In other arrangements, the device 18 can have multiple coils (e.g., two or more coils, 5-10 coils, at least 10 coils, 10-30 coils, fewer than 35 coils, fewer than 25 coils, or other suitable number of coils).

[0043] When AC current passes through one or more of the coils 90, alternating electromagnetic (e.g., magnetic) fields (wireless power signals 44) are produced that are received by one or more corresponding receiver coils, such as the coils 48 in the power receiving device 24. In other words, one or more of the coils 90 can be inductively coupled to one or more of the coils 48.

[0044] The power transmitting and receiving device 18 can also receive wireless power (e.g., from the power transmitting device 12). The coils 90 can receive alternating electromagnetic fields from the transmitting coils 36, resulting in corresponding alternating currents in the coils 90. A rectifier circuit, such as the rectifier circuit 88, which includes rectifying components, such as synchronous rectification metal oxide semiconductor transistors arranged in a bridge network, converts the AC signals received from the one or more coils 90 (received alternating signals associated with the electromagnetic signals 44) to a DC voltage signal for use in powering the device 18. The DC voltage produced by the rectifier circuit 88 can be used to charge a battery, such as the battery 94, and can be used to power other components in the device 18.

[0045] Figure 1 The depiction of alternating electromagnetic fields between each type of device is merely illustrative (to show the types of inductive coupling that are possible). In practice, the alternating electromagnetic fields will be communicated only between select devices within the system. For example, the transmitting device 12 can transmit power to the device 24 and the device 18 (while the device 18 does not individually transmit power to the device 18). In another example, the transmitting device 12 transmits power to the device 18, which transmits power to 24 (without direct power exchange from the device 12 to the device 24).

[0046] In some applications, the power transmitting and receiving device 18 only transmits wireless power (e.g., using the inverter 86 and the coil 90). In some applications, the power transmitting and receiving device 18 only receives wireless power (e.g., using the rectifier 88 and the coil 90). In some applications, the power transmitting and receiving device simultaneously receives and transmits wireless power. When simultaneously receiving and transmitting wireless power, the device 18 can optionally perform both power transmitting and power receiving operations associated with the inverter 86 and the rectifier 88 (e.g., the device 18 uses the rectifier to charge a battery and operate the device, and independently uses the inverter to transmit a desired amount of power). Alternatively, the device 18 can relay a received power signal without rectifying the power. The device 18 can include only one coil that is used for both wireless power transmission and wireless power reception. Alternatively, the device 18 can have at least one dedicated wireless power transmitting coil and at least one dedicated wireless power receiving coil. The device 18 can have multiple coils that are all used for both wireless power transmission and wireless power reception. Different coils in the device 18 can optionally be shorted together in different operating modes.

[0047] Figure 2 is a circuit diagram of an exemplary wireless charging circuit of the system 8. The wireless charging circuit of the power transmitting device 12 and the power receiving device 24 are shown. However, it should be understood that the device 18 can have corresponding components for both power transmission and power reception, and can be used in place of the device 12 and / or the device 24 if desired. As shown, the circuit 52 can include an inverter circuit such as one or more inverters 61 or other drive circuitry that generates a wireless power signal that is transmitted through an output circuit including one or more coils 36 and a capacitor such as the capacitor 71. In some embodiments, the device 12 can include multiple individually controlled inverters 61, each providing a drive signal to a respective coil 36. In other embodiments, a switching circuit is used to share an inverter 61 among multiple coils 36. Figure 2

[0048] During operation, a control signal for the inverter 61 is provided by the control circuit 16 at the control input 74. Figure 2 ​A single inverter 61 and a single coil 36 are shown in the example of FIG. 1, but multiple inverters 61 and multiple coils 36 can be used, if desired. In a multiple-coil configuration, a switching circuit (e.g., a multiplexer circuit) can be used to couple a single inverter 61 to multiple coils 36 and / or each coil 36 can be coupled to a respective inverter 61. During wireless power transmission operations, the transistors in one or more selected inverters 61 are driven by AC control signals from the control circuit 16. The relative phases between inverters can be dynamically adjusted. For example, a pair of inverters 61 can produce output signals that are in phase or out of phase (e.g., 180° out of phase).

[0049] The use of inverters 61 (e.g., transistors or other switches in the circuit 52) to apply drive signals causes the output circuit formed by the selected coil 36 and the capacitor 71 to produce an alternating electromagnetic field (signal 44) that is received by the wireless power receiving circuit 54 using the wireless power receiving circuit formed by one or more coils 48 and one or more capacitors 72 in the device 24.

[0050] The relative phases between drive coils 36 (e.g., the phase of one of the coils 36 relative to another adjacent coil 36 that is driven) can be adjusted by the control circuit 16, if desired, to help enhance the wireless power transfer between the device 12 and the device 24. The rectifier circuit 50 is coupled to one or more coils 48 (e.g., a pair of coils) and converts the received power from AC to DC and provides a corresponding DC output voltage Vrect on the rectifier output terminal 76 for use in powering load circuits in the device 24 (e.g., for charging a 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 can be included in the device 24. In an illustrative configuration, the device 24 can be a wristwatch or other portable device that has at least two coils 48. The two (or more) coils 48 can be used together when receiving wireless power. Other configurations can be used, if desired.

[0051] As previously described, the use of in-band transmission using coil 36 and coil 48 can be used to communicate (e.g., transmit and receive) information between device 12 and device 24. In one illustrative configuration, frequency shift keying (FSK) is used to transmit in-band data from device 12 to device 24, and amplitude shift keying (ASK) is used to transmit in-band data from device 24 to device 12. In other words, a device transmitting wireless power can use FSK to transmit in-band data to a device receiving wireless power (whether the device is a dedicated power transmit / receive device 12 / 24 or a power receive and transmit device 18). A device receiving wireless power can use ASK to transmit in-band data to a device transmitting wireless power (whether the device is a dedicated power transmit / receive device 12 / 24 or a power receive and transmit device 18).

[0052] During these FSK and ASK transmissions, power can be wirelessly delivered from device 12 to device 24. Although power transmit circuit 52 drives an AC signal into one or more of the coils of coil 36 at a power transmit frequency to produce signal 44, wireless transceiver circuit 40 can use FSK modulation to modulate the power transmit frequency of the driving AC signal, and thereby modulate the frequency of signal 44. In device 24, coil 48 is used to receive signal 44. Power receive circuit 54 uses the received signal on coil 48 and rectifier 50 to produce DC power. At the same time, wireless transceiver circuit 46 monitors the frequency of the AC signal passing through coil 48, and uses FSK demodulation to extract the transmitted in-band data from signal 44. This approach allows FSK data (e.g., FSK data packets) to be transmitted in-band from device 12 to device 24 through coils 36 and 48, while using coils 36 and 48 to wirelessly deliver power from device 12 to device 24.

[0053] In-band communication between device 24 and device 12 can use ASK modulation and demodulation techniques. Wireless transceiver circuit 46 transmits in-band data to device 12 by using a switch (e.g., one or more transistors in transceiver 46 that couple coil 48) to modulate the impedance of power receive circuit 54 (e.g., coil 48). This in turn modulates the amplitude of signal 44 and the amplitude of the AC signal passing through coil 36. Wireless transceiver circuit 40 monitors the amplitude of the AC signal passing through coil 36, and uses ASK demodulation to extract the transmitted in-band data from these signals transmitted by wireless transceiver circuit 46. Using ASK communication allows ASK data bits (e.g., ASK data packets) to be transmitted in-band from device 24 to device 12 through coils 48 and 36, while using coils 36 and 48 to wirelessly deliver power from device 12 to device 24.

[0054] The example of FSK modulation for communicating in-band data from the power transmitting device 12 to the power receiving device 24 and ASK modulation for communicating in-band data from the power receiving device 24 to the power transmitting device 12 is merely illustrative. In general, any desired communication technique can be used to communicate information from the power transmitting device 12 to the power receiving device 24 and from the power receiving device 24 to the power transmitting device 12.

[0055] The power transmitting frequency for wireless power transmission can be, for example, a predetermined frequency of about 125 kHz, at least 80 kHz, at least 100 kHz, between 100 kHz and 205 kHz, less than 500 kHz, less than 300 kHz, or other suitable wireless power frequency. In some configurations, the power transmission frequency can be negotiated in communication between the devices 12 and 24. In other configurations, the power transmission frequency can be fixed.

[0056] It has been described that power can be simultaneously transmitted between devices while using in-band communication for data transmission between the devices. In other words, in some examples, the in-band communication can rely on modulation of the power transmission signal (e.g., modulating the power transmission frequency or modulating the amplitude of the signal at the power transmission frequency). However, other communication techniques that do not rely on modulation of the power transmission signal can be used. For example, signals (sometimes referred to as in-band signals) can be transmitted between coils in the system at a frequency different from the power transmission frequency. Signals transmitted using coils (e.g., coils 36, 48, and 90) at the same frequency as the power transmission frequency or at a different frequency can be considered in-band signals.

[0057] Furthermore, it should be noted that in-band communication can occur between devices prior to the devices agreeing on a power transmission rate, a power transfer rate, etc. After initial detection and inductive coupling, the devices can undergo a handshake process to determine compatibility, negotiate a power transfer frequency, negotiate a power transfer rate, etc. During this process, in-band communication can involve FSK and / or ASK modulation of signals at the power transmission frequency. Thus, wireless power is transmitted during this process. This is advantageous because it allows the devices to complete the handshake process even if the power receiving device has little or no remaining battery power. This transmission of wireless power during in-band communication can occur during the handshake process even if the eventual negotiation between the devices does not result in a sustained transmission of wireless power.

[0058] The FSK and ASK modulation and demodulation techniques described above can be used to transmit data packets between two devices within the system 8. Each data packet can include a plurality of data bits (sometimes referred to as bits). The data bits can be grouped into bytes, where each byte includes any desired number of bits (e.g., 8 bits).

[0059] Data packets can be sent between devices as data streams. Many types of data can be sent between wireless power transmitting and receiving devices. For example, the data sent may include authentication data, firmware updates, commands, configuration data, power data (e.g., received power level, state of charge, etc.), or any other desired type of data.

[0060] When inductive coupling is initiated between two devices (e.g., when a wireless power receiving device is placed on a wireless power transmitting device), authentication may occur. Authentication may involve verifying that the wireless power receiving device is supported by the wireless power transmitting device and / or verifying that the wireless power receiving device and the wireless power transmitting device belong to the same user (e.g., both devices are associated with the same user identifier). Authentication may also involve establishing encryption to protect the transmitted data. These examples are merely illustrative, and other information may be transmitted during authentication.

[0061] Firmware updates can be sent, for example, between devices in System 8 (e.g., from a wireless power receiving device to a wireless power transmitting device). Commands can also be sent between devices in System 8. Exemplary commands that can be sent are instructions for updating the user interface. For example, a wireless power transmitting device can send a command to a wireless power receiving device that indicates that wireless power transfer has begun (e.g., using the input-output device 56 of the wireless power receiving device, such as a display or camera flash).

[0062] Configuration data can be transmitted from the wireless power transmitting device to the wireless power receiving device, for example. The configuration data may include information about the configuration of the wireless power transmitting device (e.g., the model and shape of the wireless power transmitting device).

[0063] In summary, many different types of data can be transmitted between devices 12, 18, and 24. However, in some communication schemes, using in-band communication between the devices, only one active data stream can exist in each communication direction. This limits the devices to transmitting only one type of data at a time. Data packets can be transmitted using data streams until all relevant data packets have been successfully transmitted. After transmission is complete, additional packets of different types can begin to be transmitted. This type of communication scheme can have limited flexibility. Once the transmission of the first type of data begins, transmission must be continuous until all of that data has been transmitted (even if there is high-priority data of different types to be transmitted).

[0064] Consider the example of placing a wireless power receiving device on a wireless power transmitting device. When the power receiving device is placed on the power transmitting device, authentication can begin (with authentication data being sent between device 12 and device 24). A single data stream can be used to send the authentication data. During this time, device 12 and device 24 can wish to exchange data regarding user interface updates. However, since only one active data stream is allowed, authentication must be completed before the user interface update commands can be exchanged. In other words, different types of data transfers must be completed consecutively.

[0065] To increase the flexibility of data communication, a communication scheme can be used that allows multiple active data streams. This allows more control over the transmission of different types of information. In the example above, the transmission of authentication data using the first data stream can be suspended, and the transmission of data regarding user interface updates using a second data stream can be used. Once the data regarding user interface updates has been transmitted, the transmission of authentication data using the first data stream can be resumed.

[0066] Additionally, it can be desirable for a given device within the system to be able to transmit data to any other device within the system. For example, consider the scenario where power transmitting device 12 is inductively coupled to device 18, device 18 is inductively coupled to power receiving device 24, and power transmitting device 12 is not inductively coupled to power receiving device 24. It can be desirable for power transmitting device 12 to transmit data to power receiving device 24. However, because power transmitting device 12 and power receiving device 24 are not inductively coupled, power transmitting device 12 cannot transmit data directly to power receiving device 24 using in-band communication.

[0067] To increase the flexibility of communication within the system, packets exchanged within the system can have information identifying a target address within the system. For example, power transmitting device 12 can generate a packet intended for device 24. The packet can include information identifying device 24. Power transmitting device 12 can transmit the packet to device 18 using in-band communication. However, because of the address information, device 18 uses in-band communication to transmit the packet to the intended target of power receiving device 24. In this way, even though power transmitting device 12 is not inductively coupled, the power transmitting device can transmit the desired information to power receiving device 24.

[0068] Thus, the communication scheme for system 8 can allow for multiple concurrent data streams between any two devices in the system, as well as packet transmission, regardless of whether they are inductively coupled. Packets can be transmitted using in-band communication. To allow for multiple concurrent data streams, each packet can include stream identification information in the header. To allow for packet transmission between any two devices in the system, an addressing scheme can be used that is based on the topology of the communication network.

[0069] Figure 3Ais a schematic diagram showing an illustrative arrangement for system 8. As shown, there can be one wireless power transmitting device 12 that transmits wireless power to wireless power transmitting and receiving device 18 and wireless power receiving devices 24B and 24C. Wireless power transmitting and receiving device 18 receives power from transmitter 12 and transmits power to wireless power receiving device 24A.

[0070] Figure 3B is Figure 3A a network diagram of the system of Figure 3B As shown, each device within the system is represented as a corresponding node within the network. Power receiving device 24A is represented as node N0, power transmitting and receiving device 18 is represented as node N1, power transmitting device 12 is represented as node N2, power receiving device 24C is represented as node N3, and power receiving device 24B is represented as node N4. The nodes are connected by links 98, where each link represents an inductive coupling between nodes. Links 98 between nodes can sometimes be referred to as inductive links, inductive couplings, inductive coupling links, interfaces, inductive interfaces, etc.

[0071] In-band communication can be used for bidirectional communication over each inductive link 98. In one illustrative arrangement, a device that transmits wireless power over an inductive link uses FSK modulation to transmit packets over the inductive link, and a device that receives wireless power over an inductive link uses ASK modulation to transmit packets over the inductive link. In general, a device can use any desired modulation scheme for in-band communication over an inductive link (e.g., using a coil).

[0072] Each node can be a relay node or a host node. Each host node (sometimes referred to as an endpoint node) is linked to only one other node within the network. For example, node N0 is a host node that is linked to only node N1. Host node N4 is linked to only one other node (N2). Host node N3 is linked to only one other node (N2). On the other hand, a relay node can be linked to at least two other nodes within the network. For example, relay node N1 is linked to nodes N0 and N2. Relay node N2 is linked to nodes N1, N3, and N4.

[0073] In terms of functionality, a host node can be used to receive, process, and transmit packets over its single link. In other words, a host node is used to transmit packets to and receive packets from a single device with which it is inductively coupled. For example, consider host node N0. Host node N0 can use the inductive link between N0 and N1 to transmit packets to node N1. Host node N0 can use the inductive link between N0 and N1 to receive packets from node N1. However, because N0 is only inductively coupled to N1, N0 cannot transmit in-band communication packets directly to any other node within the network. However, because N0 is only inductively coupled to N1, N0 cannot transmit in-band communication packets directly to any other node within the network.

[0074] A relay node is able to relay packets from one node to another (e.g., between two hosts). For example, relay node N1 can receive a packet from host node N0 and transmit the packet to relay node N2. Similarly, relay node N1 can receive a packet from relay node N2 and then transmit the packet to host node N0. Thus, a relay node can be used to distribute packets within the network to a desired target.

[0075] The communication network associated with system 8 can have an associated network depth and branching limit. The network depth can refer to the maximum number of supported links between any two nodes in the network. The branching limit refers to the maximum number of supported nodes that are directly connected to a single relay. In Figure 3B there are three links separating node N0 from node N3. Thus, a network depth of three is needed to support Figure 3B the network. Relay node N2 is linked to three other nodes. Thus, a branching limit of three is needed to support Figure 3B the network.

[0076] As previously mentioned, the topology of the network can be used as a basis for an addressing scheme for communication within the system. This type of communication scheme allows for simple and fast communication between any two nodes in the network without relying on a unique device identifier (which can require more data and can include more identifying information than is necessary for inter-device communication within the network).

[0077] The topology of the network can be determined whenever an inductive link is added or removed from the network. The process of determining the network topology can be referred to as a network discovery process. At the end of the network discovery process, each device in the network can have an internal device list that includes all other devices in the network and their relative positions in the network.

[0078] For example, consider the example of Figure 4A and Figure 4B In Figure 4Aa schematic diagram, power receiving device 24B has been removed from the system (relative to Figure 3A a schematic diagram). The network graph associated with the system of Figure 4A Figure 4B is shown in Figure 4B As shown, there are four devices in total within the network. Thus, the network discovery process will provide each device with a list of the other three devices in the network and addresses for the other three devices based on the location of the device within the network.

[0079] Figure 5 is a flowchart of exemplary operations involving a network discovery process that occurs each time a device is added or removed from a communication network. Figures 6A-6E is a diagram showing the various steps of the network discovery process. During the operation of block 102, the relay node assigns a unique number to each interface that has an active connection. In other words, each relay node assigns a unique number to each inductive link that it has with another device in the network.

[0080] As shown in Figure 6A , power transmitting and receiving device 18 is a relay node N1 in the network, and power transmitting device 12 is a relay node N2 in the network. Thus, each of these nodes assigns a unique number to each inductive link that exists. Node N1 has two inductive links (one with node N0, and one with node N2). Thus, the node assigns a unique number to each of these two inductive links. The unique number can be determined randomly. The magnitude of the number is not important, as long as different links have some different identifier. In Figure 6A , relay node N1 assigns the link with node N0 as number "1", and assigns the link with node N2 as number "2".

[0081] Node N2 also has two inductive links (one with node N1, and one with node N3). Thus, the node assigns a unique number to each of these two inductive links. In Figure 6A , relay node N2 assigns the link with node N1 as number "1", and assigns the link with node N3 as number "2".

[0082] Next, during the operation of block 104, each node constructs an internal device list that includes the devices that it is inductively coupled to. In other words, each device begins constructing a device list that will eventually show the devices of the entire network. However, initially, each device only knows the devices that it is directly linked to (via inductive coupling). The interface number assigned to the inductive link of the device can be used as the address of the device. An example of the operation of block 104 is shown in Figure 6B ​​

[0083] In Figures 6B-6E each device list will be shown under its corresponding node (e.g., device list 114-0 for node N0 is shown under node N0, device list 114-1 for node N1 is shown under node N1, etc.). First, consider the device list 114-0 for node N0 in Figure 6B . By definition, each host node has only one inductive link. Thus, that one inductive link can have a default assigned number. In this example, the host assigns the identifier "0" to its inductive link. However, because the number is only for identification purposes, the magnitude of the number is not important. Thus, host node N0 has one link device (at node N1) to include in its device list. The device list can identify the type of device at node N1 (e.g., device 18, which can be a removable battery case, a wireless charging pad, a portable electronic device, etc.). Assign the address "0" in list 114-0 to device 18, as this is the number assigned to the inductive link between N0 and N1 in this example.

[0084] Next, consider the device list 114-1 for relay node N1 in Figure 6B . As shown previously in Figure 6A , node N1 has the identifier "1" for the inductive link with node N0. Thus, device list 114-1 assigns device 24A (e.g., a device connected using inductive link "1") the address 1. Node N1 assigns the inductive link with node N2 the identifier "2". Thus, device list 114-1 assigns device 12 the address 2.

[0085] A similar process is performed for device lists 114-2 and 114-3. As shown previously in Figure 6A , node N2 has the identifier "1" for the inductive link with node N1. Thus, device list 114-2 assigns device 18 the address 1. Node N2 assigns the inductive link with node N3 the identifier "2". Thus, device list 114-2 assigns device 24C the address 2.

[0086] Finally, consider the device list 114-3 for host node N3 in Figure 6B . Again, in this example, the host assigns the identifier "0" to its inductive link. Host node N3 has one link device (at node N2) to include in its device list. The device list can identify the type of device at node N2 (e.g., device 12, which can be a wireless charging pad, a wireless charging disc, etc.). Assign the address "0" in list 114-3 to device 12, as this is the number assigned to the inductive link between N3 and N2 in this example.

[0087] After building the initial device list, execute Figure 5 The operation in box 106 is as follows. Specifically, during the operation of box 106, each relay node reports its device list to each connected node (including both the host node and other relay nodes). During the operation of box 108, each node adds new devices from the received device list to its internal device list. Specifically, the node adding a new device to its internal device list may append the interface number from the device list it received to the address of the new device. Figure 6C and Figure 6D The process is illustrated.

[0088] like Figure 6C As shown, relay node N1 can send its device list to connected nodes N0 and N2, as indicated by arrow 116. Host node N0 receives the device list from node N1 (which identifies devices 12 and 24A). Node N0 is device 24A, so the device is not added to N0's device list (because its internal device list does not include itself). However, the device list received from node N1 also identifies device 12, which is not yet included in device list 114-0. Therefore, device 12 is added to N0's device list 114-0, as highlighted by the dashed box around the entry. The address of device 12 is copied from the received device list (e.g., "2" from device list 114-1), and a 0 is appended to that address. The "0" is appended to the address because device 24A received the device list identifying device 12 from its "0" link. Therefore, the address of device 12 in device list 114-0 is 0.2.

[0089] Relay node N2 also receives a device list from node N1 (which identifies devices 12 and 24A). Node N2 is device 12, so the device is not added to N2's device list (because its internal device list does not include itself). However, the device list received from node N1 also identifies device 24A, which is not yet included in device list 114-2. Therefore, device 24A is added to N2's device list 114-2, as highlighted by the dashed box around the entry. The address of device 24A is copied from the received device list (e.g., "1" from device list 114-1), and a 1 is appended to that address. The "1" is appended to the address because device 12 received the device list identifying device 24A from its "1" link. Therefore, the address of device 24A in device list 114-2 is 1.1.

[0090] Next, as Figure 6DAs shown, the relay node N2 can send its device list to the connected nodes N1 and N3, as indicated by arrow 116. The host node N3 receives the device list from node N2, which identifies devices 18, 24C, and 24A. Node N0 is device 24C, such that the device is not added to the N3 device list (as the internal device list does not include itself). However, the device list received from node N2 also identifies devices 18 and 24A, which are not already included in the device list 114-3. Accordingly, devices 18 and 24A are added to the device list 114-3 for N3, as highlighted by the dashed box in Figure 6D The address for device 18 is copied from the received device list (e.g., "1" from device list 114-2) and a "0" is appended to the address. The "0" is appended to the address because device 24C received the device list identifying device 18 from its "0" link. Accordingly, the address for device 18 is 0.1 in device list 114-3. The address for device 24A is copied from the received device list (e.g., "1.1" from device list 114-2) and a "0" is appended to the address. The "0" is appended to the address because device 24C received the device list identifying device 24A from its "0" link. Accordingly, the address for device 24A is 0.1.1 in device list 114-3.

[0091] The relay node N1 also receives the device list from node N2, which identifies devices 18, 24C, and 24A. Node N1 is device 18, such that the device is not added to the N1 device list (as the internal device list does not include itself). Node N1 is device 18, such that the device is not added to the N1 device list (as the internal device list does not include itself). The device list 114-1 for node N1 already includes device 24A. Accordingly, even though the received device list from node N2 includes device 24A, device 24A is not added to device list 114-1 (as such an entry would be redundant). The device list received by node N1 from node N2 also identifies device 24C, which is not already included in device list 114-1. Accordingly, device 24C is added to the device list 114-1 for N1, as highlighted by the dashed box in Figure 6D The address for device 24C is copied from the received device list (e.g., "1.2" from device list 114-2) and a "2" is appended to the address. The "2" is appended to the address because device 18 received the device list identifying device 24C from its "2" link. Accordingly, the address for device 24C is 2.2 in device list 114-1.

[0092] Next, in Figure 5during the operation of block 110 in FIG. 1 10, a relay node that has updated its internal device list can send the updated device list to each connected node (except the node from which the device list was received). An example of this type is shown in FIG. 1 12. Consider first relay node N2. Relay node N2 has updated its device list to include device 24A. However, since the device list including device 24A has already been sent to node N3, the relay node does not need to send the device list to node N3 again. Since node N2 received the device list with newly added device 24A from node N1, node N2 does not need to send the device list back to node N1. Thus, node N2 does not need to re-distribute its device list to any connected nodes. Figure 6E

[0093] Meanwhile, node N1 has updated its device list to include device 24C. Since node N1 received the device list with newly added device 24C from node N2, node N1 does not need to send the device list back to node N2. However, since node N1 has not sent its device list to node N0 since device 24C was added, node N1 can send its updated device list to node N0, as indicated by arrow 116 in FIG. 1 12. Figure 6E Figure 5 The flowchart of FIG. 1 12 loops back to the operation of block 108 in response to a device list being newly distributed.

[0094] Host node N0 receives the new device list from node N1 (which identifies devices 24A, 12, and 24C). Node N0 is device 24A, so that device is not added to the N0 device list (since the internal device list does not include itself). The device list 1 14-0 for node N0 already includes device 12. Thus, even though the device list received from node N1 includes device 12, device 12 is not added to device list 1 14-0 (since such an entry would be redundant). The device list received by node N0 from node N1 also identifies device 24C, which is not already included in device list 1 14-0. Thus, device 24C is added to the N0 device list 1 14-0, as highlighted by the dashed box in FIG. 1 12. Figure 6E The address of device 24C is copied from the received device list (e.g., "2.2" from device list 1 14-1 ), and a "0" is appended to the address. The "0" is appended to the address because device 24A received the device list identifying device 24C from its "0" link. Thus, the address of device 24C is 0.2.2 in device list 1 14-0.

[0095] Figure 5 The operations of blocks 108 and 1 10 in FIG. 1 12 can repeat until the network is fully discovered. When Figure 5 ​​If step 108 in the process does not prompt for an updated list distribution as in step 110, the network can be fully discovered. For example, in Figure 6E In this process, relay node N1 sends its device list to host node N0. Host node N0 does not redistribute the device list, and there are no other relay node updates to distribute. Therefore, the network discovery process is complete.

[0096] like Figure 6E As shown, at the end of the network discovery process, each device has a corresponding device list that includes all other devices in the network. This device list can identify the type of the device (e.g., power transmitting device, power transmitting and receiving device, power receiving device, etc.). However, the device type included in the device list may be unknown to a specific user of the device. In one example, the device type can identify the brand, model, and / or type of each device (e.g., cellular phone, wristwatch, tablet, etc.).

[0097] The addresses included in each device list are temporary addresses based on the current network topology. If the network topology changes, the addresses will also change. Therefore, the addresses are sometimes referred to as locally assigned addresses or simply local addresses. Specifically, each address in the device list of a given device identifies an inductive coupling path from the given device to every other device in the list. This address provides an inductive coupling path map from the given device to each device in the list, where each number identifies the corresponding inductive coupling link. For example, consider device list 114-0 (node ​​N0) for device 24A. Device list 24A includes device 18 with address 0. Address 0 indicates that device 18 is located at inductive coupling link "0" of device 24A. Next, device list 24A includes device 12 with address 0.2. To reach device 12, follow the inductive path to device 18 indicated by the first digit (0). Then, the next digit of the address ("2") identifies inductive link 2 leading to device 12. Once there are no more digits remaining in the address, the destination address has been reached.

[0098] For example, device list 114-0 includes device 24C with address 0.2.2. To reach device 24C from device 24A, follow the sensing path to device 18 indicated by the first digit (0). Then, the next digit of the address ("2") identifies sensing link 2 associated with device 12. Follow sensing path "2" from device 18 to device 12. The next (and last) digit of the address is "2". This identifies sensing link 2 associated with device 24C. Follow sensing path 2 from device 12 to the target device 24C.

[0099] Thus, each number in the address represents an inductive link between devices within the network. By following the inductive links identified in the address, a packet can be sent to a target device. For example, consider the device list 114-3 for device 24C. Device 24A has an address of 0.1.1 in the list 114-3. To reach device 24A, follow the path along device 24C's inductive link 0 (the first address number) to a first intervening device (device 12). The first intervening device follows its inductive link 1 (the second address number) to a second intervening device (device 18). The second intervening device follows its inductive link 1 (the third address number) to the target device (device 24A). In this way, any device within the network can communicate with any other device within the network using a target address. Each target address provides a path of inductive links (e.g., inductive coupling paths) to navigate the network topology and reach the desired target device. This addressing scheme has the beneficial effect of providing instructions on how to reach a target device, rather than merely providing the identity of the target device.

[0100] Various packet structures can be used to enable the combination Figure 5 and Figures 6A-6E addressing scheme described. Figure 7 is an illustration of an exemplary packet 202. In general, the packet 202 can have a preamble 204 (e.g., one or more preamble bytes), a header 206 (e.g., one or more header bytes), a message 208 (e.g., one or more message bytes), and a checksum 210 (e.g., one or more checksum bytes). The preamble 204 can include a sequence of bits that enables a data packet receiving device to accurately detect the start bit of the header. The header 206 can indicate the type of data packet being sent. The header information can include, for example, a stream number identifying a stream number to which the data packet belongs, a target address for the packet, a flag indicating whether a multiple-pass scenario exists, etc. The message 208 (sometimes referred to as a payload) includes the data desired to be sent. The payload can be data, instructions, requests, etc. The checksum 210 allows verification that the entire packet has been successfully sent. A device receiving the packet can calculate a checksum value for the packet and compare the calculated checksum value to a target checksum value received in the checksum bytes. If the calculated checksum value matches the target checksum value, the packet is interpreted as being successfully sent. If the calculated checksum value does not match the target checksum value, the packet transmission is interpreted as including an error.

[0101] Figure 8 is an illustration of an exemplary packet structure for a device list (e.g., the device lists 114-0, 114-1, 114-2, or 114-3 in Figures 6B-6E . Specifically, the payload including the device list is shown in Figure 8 , but it should be understood thatFigure 7 Other grouping components can also be included in a group that has a device list. As shown in the figure, the device list can be represented by multiple bytes. Figure 8 In this example, each byte is depicted as having 8 bits. This example is merely illustrative, and each byte can have any desired number of bits. The first byte (B0) may identify the first device type (e.g., device 0 device type). The second byte (B1) may identify the device address associated with the first device (e.g., device 0 address). The third byte (B2) may identify the second device type (e.g., device 1 device type). The fourth byte (B3) may identify the device address associated with the second device (e.g., device 1 address). This pattern can continue, with byte pairs identifying device types and addresses, until all devices in the list are identified.

[0102] Each time the device list is sent (e.g.) Figures 6B-6E As shown), the device list can be used as a... Figure 8 The packets are transmitted according to the arrangement shown. The packet payload (identifying the device, such as...) Figure 8 The example shown can have twice the number of bytes for the identified device (because each device has two associated bytes). This example is merely illustrative, and other grouping structures can be used to transfer device lists between devices if needed.

[0103] Figure 9 This is an illustration of an exemplary header that can be used in packets sent in System 8. It should be understood that... Figure 9 The header in can include Figure 7 It is part of the grouping of other grouped components. For example... Figure 9 As shown, the first byte may include three bits dedicated to identifying the stream number associated with the packet. The first three bits of the stream header (bits b0, b1, and b2) are used to identify the stream number of the data packet. In this example, the three identifier bits allow for eight active streams. In other words, bits b0 through b2 will be used to identify stream numbers 0, 1, 2, 3, 4, 5, 6, or 7. This example is merely illustrative. In general, any desired number of bits (e.g., one, two, three, four, more than four, etc.) can be used to identify the stream number.

[0104] In some embodiments, 1 bit is used to identify the stream number. In some embodiments, 2 bits are used to identify the stream number. In some embodiments, 3 bits are used to identify the stream number. In some embodiments, 4 bits are used to identify the stream number. In some embodiments, 5 bits are used to identify the stream number. In some embodiments, 6 bits are used to identify the stream number. In some embodiments, 7 bits are used to identify the stream number. Note that any combination of stream identification bits and header length can be implemented so long as there are enough bits. For example, in an 8-bit header, any of the 1-8 bits can be reserved for stream identification. In a 16-bit header, any of the 1-16 bits can be reserved for stream identification. In a 24-bit header, any of the 1-24 bits can be reserved for stream identification. In a 32-bit header, any of the 1-32 bits can be reserved for stream identification. In a 48-bit header, any of the 1-48 bits can be reserved for stream identification. In a 64-bit header, any of the 1-64 bits can be reserved for stream identification.

[0105] As shown in FIG. 3, the first byte (B0) of the header can be used to identify the source address of the packet (e.g., where the packet originated). The second byte (B1) of the header can be used to identify the target address of the packet (e.g., the intended target device of the packet). Figure 9

[0106] Bits b3-b5 of the first byte of the header can be reserved. Bit b6 of B0 can be used to indicate a broadcast mode. In a broadcast mode, a given payload is intended to be distributed (broadcasted) to every device in the network. If the broadcast bit is a positive indicator of a broadcast mode (e.g., a “1” bit flagging a broadcast mode), the target address in the header can be ignored or considered invalid. Conversely, a device receiving a packet flagged with a broadcast mode will send the packet to all other devices it inductively couples to. In this way, the packet is distributed throughout the network without having to send individual packets with directed target addresses to each device. In summary, if bit b6 is a negative indicator of a broadcast mode (e.g., a “0” can indicate that no broadcast mode is present), the target address in the header can be used to inform the sending of the packet. If bit b6 is a positive indicator of a broadcast mode (e.g., a “1” can indicate that a broadcast mode is present), the target address in the header can be ignored.

[0107] ​Bit b7 of B1 can be used to indicate a multi-device mode. In the multi-device mode, there can be at least three electronic devices in the communication network. If there are only two devices, the packet can be exchanged between only the two devices. In this case, the destination address need not be used because there is only one destination address available. Thus, if there are only two devices in the network, the multi-device mode can be negative (e.g., "0") and the destination address field can be empty or invalid. If there are three devices, additional header information can be used to identify the destination of each packet. If the mode bit is a positive indicator of the multi-device mode (e.g., a "1" bit), the destination address can be used to inform the packet of possible further transmission. In summary, bit b7 can be a negative indicator of the multi-device mode (e.g., "0") when there are only two devices in the network. Bit b7 can be a positive indicator of the multi-device mode (e.g., "1") when there are more than two devices in the network. The destination address can be used when the multi-device mode is flagged and can be invalid when the multi-device mode is not flagged.

[0108] Figure 10 is an example address byte that can be used for addresses in Figure 8 and / or Figure 9 . As shown in Figure 10 , an address (e.g., a source address or a destination address) can be represented by four branch numbers, where each branch number includes two corresponding bits. Each branch number represents an inductively coupled path within the network. Each branch number can be a number of the destination address. For example, Figure 6E the address 0.2.2 in the list 114-0 in

[0109] Figure 10 The examples of addresses having one byte in Figure 10 are merely illustrative. One or more bytes can be used to represent an address. The structure of the address byte can affect the type of network topology supported by the address byte. The number of branch numbers included in the address byte is equal to the supported network depth of the communication network. For example, in Figure 10 , there is space for four branch numbers. Thus, there can be up to four inductive links between two nodes in the network. Additional branch numbers can be included in the address byte to support greater network depth.

[0110] The number of bits included in each branch number can affect the branch limit of the communication network. Including more bits in each branch number will allow a given device in the network to be coupled to more devices.

[0111] Figure 10The example of an address byte with four branch numbers is merely illustrative. An address byte can have two branch numbers, three branch numbers, five branch numbers, six branch numbers, more than six branch numbers, more than eight branch numbers, more than ten branch numbers, more than fifty branch numbers, etc. In some embodiments, each branch number can include one bit. In some embodiments, each branch number can include two bits. In some embodiments, each branch number can include three bits. In some embodiments, each branch number can include four bits. In some embodiments, each branch number can include more than four bits. In some embodiments, each branch number can include six bits. Note that any combination of branch numbers and bits per branch number can be implemented so long as there are enough bits. For example, in an address with two branch numbers, any number of bits between 1 and 6 can be used in each branch number. In an address with three branch numbers, any number of bits between 1 and 6 can be used in each branch number. In an address with four branch numbers, any number of bits between 1 and 6 can be used in each branch number. In an address with five branch numbers, any number of bits between 1 and 6 can be used in each branch number. In an address with six branch numbers, any number of bits between 1 and 6 can be used in each branch number.

[0112] In conjunction with Figures 5-10 The addressing schemes shown and described enable devices in the network to send packets to any other device in the network, even if they are not inductively coupled. Figure 11 is a flowchart of illustrative operations involved in passing a packet from a given device to an additional device in the network that is not inductively coupled to the given device. Figures 12A-12C is a diagram showing the various steps of the packet sending process.

[0113] During the operation of block 302, a device in the network (e.g., device 24C in Figure 12A identifies a target device (e.g., the ultimate target) for the packet (while using the coil to send or receive power). In the example of Figure 12A device 24C intends to send a packet to device 24A. The packet is created using the address of the target device from the list of devices of the initial device. In the example of Figure 12A the packet can use address 0.1.1 (associated with target device 24A) as the target address. The source address can be “0” or “null” (e.g., since device 24C is creating the packet without another source for the packet).

[0114] During the operation of block 304, the first number of the target address can be removed. As Figure 12AAs shown, device 12 removes the first digit from the received target address (1.1), resulting in a target address of 1. Device 12 then transmits the packet using the interface identified by the removed digit (1). In other words, device 12 transmits the packet to device 18 over inductive link 1, as shown.

[0115] During operation of block 308, the device receiving the packet can append the interface number from which the packet was received to the source address in the packet (e.g., as a new first digit in the source address). For example, device 12 receives the packet using inductive link 2 in block 306. Accordingly, device 12 can append "2" to the source address of the packet. Operation can then return to block 304, and the operations of blocks 304-308 can be repeated. The operations of blocks 302, 304, 306, and 308 can each be performed while wireless power is being transmitted between devices in the network. Figure 12A

[0116] As shown, device 12 removes the first digit from the received target address (1.1), resulting in a target address of 1. Device 12 then transmits the packet using the interface identified by the removed digit (1). In other words, device 12 transmits the packet to device 18 over inductive link 1, as shown. Figure 12B Figure 12B As shown, device 12 removes the first digit from the received target address (1.1), resulting in a target address of 1. Device 12 then transmits the packet using the interface identified by the removed digit (1). In other words, device 12 transmits the packet to device 18 over inductive link 1, as shown. Figure 12B As shown, device 12 removes the first digit from the received target address (1.1), resulting in a target address of 1. Device 12 then transmits the packet using the interface identified by the removed digit (1). In other words, device 12 transmits the packet to device 18 over inductive link 1, as shown.

[0117] Figure 12C As shown, device 12 removes the first digit from the received target address (1.1), resulting in a target address of 1. Device 12 then transmits the packet using the interface identified by the removed digit (1). In other words, device 12 transmits the packet to device 18 over inductive link 1, as shown. Figure 12C Figure 12C As shown, device 12 removes the first digit from the received target address (1.1), resulting in a target address of 1. Device 12 then transmits the packet using the interface identified by the removed digit (1). In other words, device 12 transmits the packet to device 18 over inductive link 1, as shown.

[0118] When the target device finally receives the packet and appends the inductive link number to the source address, the resulting source address indicates the device that initiated transmission of the packet. For example, in Figure 12C ​​​​In this case, the source address 0.2.2 is the same as the address of device 24C in the device list of device 24A. Thus, device 24A knows that the packet originated from device 24C.

[0119] In this way, packets can be passed between any device in the network (e.g., even devices that are not inductively coupled). In-band communication (e.g., using FSK modulation or ASK modulation) can be used for each transmission of a packet across an inductive link. The target address is used as a roadmap to direct the transmission of the packet to the final target. The source address is recorded as the packet passes through the network so that a receiving device receives the source address, which identifies which node transmitted the packet.

[0120] In Figure 11 and Figures 12A-12C the example, the device removes the first number in the target address and then transmits the packet using the inductive link identified by the removed number. It should be appreciated that this example is merely illustrative. In another possible implementation, the device can transmit the packet based on the first bit number in the target address. Upon receiving the packet, the device then removes that first bit number in the target address. In other words, the number can be removed from the target address on either the transmitter or receiver side of the transmission. Similarly, the number can be appended to the source address on either the transmitter or receiver side of the transmission.

[0121] There are various types of data packets that can be transmitted during operation of one or more data streams using a wireless power system. An auxiliary data control (ADC) packet can be used to turn on and off (activate and deactivate) a data stream. An auxiliary data transmit (ADT) packet can be used to transmit data using an active data stream. A data stream response (DSR) packet can allow for an acknowledgement to be transmitted upon successful receipt of data. All of these types of packets can include a header that identifies a corresponding stream number as well as a target address for the packet (e.g., a header as shown in Figure 9 Since the packets are enabled to function in a wireless network with three or more devices (e.g., a network that can make multiple passes), the packets can be referred to as multi-device or multi-pass packets. The abbreviations M-ADT, M-ADC, and M-DSR can be used for ADT, ADC, and DSR packets that are passed multiple times within a network.

[0122] Figure 13 is an illustration of an exemplary operation that can be used to turn on a data stream between two devices in a network that are not inductively coupled. As shown in Figure 13 there can be a first wireless power receiving device RX1, a wireless power transmitting device TX, and a second wireless power receiving device RX2 in the system. Device RX1 and TX are inductively coupled. Device RX2 and TX are inductively coupled. Device RX1 and RX2 are not inductively coupled. However, RX1 can initiate the turn on of a data stream with RX2.

[0123] like Figure 13 As shown, RX1 can send an Auxiliary Data Control Packet (M-ADC) packet 402 to the transmitting device TX. The M-ADC packet can identify RX2 as the destination address for the packet. The M-ADC packet may include a payload with a request to open a data stream using RX2. In response to receiving the M-ADC packet, the transmitting device TX can reply to RX1 using an acknowledgment packet (ACK) 404. Next, TX can receive a DSR / POLL packet 406 from RX2 (indicating that RX2 is available to receive packets). In response, TX sends an M-ADC packet 408 to RX2. The payload of the M-ADC packet 408 can remain unchanged between transmissions between RX1 and TX and between TX and RX2. In response to receiving the M-ADC packet, RX2 can respond to TX using a DSR / ACK packet 410 acknowledging receipt of the M-ADC packet.

[0124] Next, RX2 can send an M-DSR 412 packet to TX. The M-DSR packet can identify RX1 as the destination address for the packet. The M-DSR packet may include a payload that acknowledges the opening of a data stream using RX1. In response to receiving the M-DSR packet, the transmitting device TX can reply to RX2 using an acknowledgment packet (ACK) 414. Next, TX can receive a DSR / POLL packet 416 from RX1 (indicating that RX1 is available to receive packets). In response, TX sends an M-DSR packet 418 to RX1. The payload of the M-DSR packet 418 can remain unchanged between the transmission between RX2 and TX and the transmission between TX and RX1. In response to receiving the M-DSR packet, RX1 can respond to TX using a DSR / ACK packet 420 acknowledging receipt of the M-DSR packet.

[0125] Using this type of communication scheme, data streams can be opened and closed between devices that are not inductively coupled within the network. It should be noted that... Figure 13 Acknowledgment packets (e.g., packets 404, 410, 414, and 420) may not be transmitted between multiple sensor links. Therefore, these packets may have an empty or invalid destination address and a mode field indicating transmission over a single sensor link (see [link to relevant documentation]). Figure 9 Additionally, if necessary, the transmitting device TX may optionally respond to RX2 after receiving DSR / ACK 410. The transmitting device TX may also optionally respond to RX1 after receiving DSR / ACK 420.

[0126] Figure 14is an illustration of exemplary operations that can be used to transfer data in an active data stream between two devices that are not inductively coupled in a network. As Figure 14 illustrated, there can be a first wireless power receiving device RX1, a wireless power transmitting device TX, and a second wireless power receiving device RX2 in the system. Device RX1 and TX are inductively coupled. Device RX2 and TX are inductively coupled. Devices RX1 and RX2 are not inductively coupled. However, RX1 can send data to RX2 through an active data stream.

[0127] As Figure 14 illustrated, RX1 can send an auxiliary data transfer packet (M-ADT) packet 502 to the transmitting device TX. The M-ADT packet can identify RX2 as the target address for the packet. The M-ADT packet can include a payload with data for RX2 and can identify a stream number to which the data corresponds. In response to receiving the M-ADT packet, the transmitting device TX can reply to RX1 with an acknowledgement packet (ACK) 504. Next, TX can receive a DSR / POLL packet 506 from RX2 (indicating that RX2 is available to receive a packet). In response, TX sends an M-ADT packet 508 to RX2. The payload of the M-ADT packet 508 can remain unchanged between the transmission between RX1 and TX and the transmission between TX and RX2. In response to receiving the M-ADT packet, RX2 can respond to TX with a DSR / ACK packet 510 acknowledging receipt of the M-ADT packet.

[0128] Next, RX2 can send an M-DSR 512 packet to TX. The M-DSR packet can identify RX1 as the target address for the packet. The M-DSR packet can include an acknowledgement of data received from RX1 and / or additional data intended for RX1. In response to receiving the M-DSR packet, the transmitting device TX can reply to RX2 with an acknowledgement packet (ACK) 514. Next, TX can receive a DSR / POLL packet 516 from RX1 (indicating that RX1 is available to receive a packet). In response, TX sends an M-DSR packet 518 to RX1. The payload of the M-DSR packet 518 can remain unchanged between the transmission between RX2 and TX and the transmission between TX and RX1. In response to receiving the M-DSR packet, RX1 can respond to TX with a DSR / ACK packet 520 acknowledging receipt of the M-DSR packet.

[0129] Using this type of communication scheme, data can be transferred between devices that are not inductively coupled in a network. It should be noted that, Figure 14Acknowledgment packets (e.g., packets 404, 410, 414, and 420) in the above-described embodiments can not be passed between multiple inductive links. Thus, these packets can have a null or invalid destination address and a mode field indicating passage through a single inductive link (see Figure 9 ) Additionally, if desired, the transmitting device TX can optionally respond to RX2 after receiving the DSR / ACK 510. The transmitting device TX can also optionally respond to RX1 after receiving the DSR / ACK 520.

[0130] In Figure 13 and Figure 14 , in-band communication (e.g., using FSK modulation or ASK modulation) can be used for each of the depicted packet transmissions.

[0131] If desired, devices in system 8 can communicate using separate antennas (e.g., antennas coupled to wireless transceiver circuitry 40, 46, and 80 in Figure 1 instead of coils. For example, Bluetooth communication can be used for wireless communication between devices. In one illustrative example, network discovery procedures and other initial communication can rely on in-band communication (e.g., communication using coils 36, 48, and 90). After network discovery is complete, in-band communication can be used for devices within the system to exchange Bluetooth credentials, after which those devices can optionally switch to Bluetooth communication instead of in-band communication, if desired.

[0132] According to one embodiment, an electronic device capable of operating in a wireless charging system having at least first and second additional electronic devices, the electronic device inductively coupled to the first additional electronic device and not inductively coupled to the second additional electronic device, the electronic device configured to include: at least one coil configured to receive a wireless power signal from the first additional electronic device; a rectifier circuit configured to convert the wireless power signal to a direct current power; and a control circuit configured to assign an address to the first and second additional electronic devices and to communicate with the first and second additional electronic devices using the at least one coil using the address.

[0133] According to another embodiment, the control circuit is configured to assign the address to the first and second additional electronic devices during a network discovery procedure.

[0134] According to another embodiment, the control circuit is configured to generate an internal device list including one or more devices to which the electronic device is inductively coupled during a network discovery procedure.

[0135] According to another implementation, the internal device list includes a device type and an address for each of one or more devices to which the electronic device inductively couples.

[0136] According to another implementation, the address assigned to each of the one or more devices is equal to an identifier for an inductive link through which the electronic device inductively couples to the respective device.

[0137] According to another implementation, the control circuit is configured to receive an external device list from a first additional electronic device during a network discovery process, the external device list identifying the second additional electronic device, and in response to receiving the external device list from the first additional electronic device, add the second additional electronic device to the internal device list.

[0138] According to another implementation, the second additional electronic device has a first address in the external device list, the second additional electronic device has a second address in the internal device list, and the second address is different than the first address.

[0139] According to another implementation, the control circuit is configured to append an identifier of an inductive link through which the external device list is received to the first address to produce the second address.

[0140] According to another implementation, the external device list identifies a third additional electronic device that inductively couples to the second additional electronic device and does not inductively couple to the first additional electronic device, and the control circuit is configured to add the third additional electronic device to the internal device list.

[0141] According to another implementation, the address identifies an inductive coupling path within the wireless charging system.

[0142] According to another implementation, each address has a multi-digit number and each digit identifies a respective inductive coupling path within the wireless charging system.

[0143] According to another implementation, the control circuit is configured to include addresses for the first and second additional electronic devices in the internal device list that includes the first and second additional electronic devices.

[0144] According to one implementation, an electronic device capable of operating in a wireless charging system having at least first and second additional electronic devices, the electronic device is provided to include wireless power circuitry comprising at least one coil and control circuitry configured to exchange packets with the first and second additional electronic devices using the at least one coil, the packets containing locally assigned addresses that identify inductive coupling paths within the wireless charging system.

[0145] According to another implementation, the control circuit is configured to receive an external device list from the first additional electronic device during a network discovery process, add a new device from the external device list to an internal device list, and send the internal device list to the second additional electronic device.

[0146] According to another implementation, the new device has a first address in the external device list from the first additional electronic device, the new device has a second address in the internal device list, and the second address is different from the first address.

[0147] According to another implementation, the control circuit is configured to add a number representing an inductive coupling path to the first address to obtain the second address.

[0148] According to another implementation, the external device list received from the first additional electronic device includes a first plurality of bytes identifying a device type of each device in the external device list and a second plurality of bytes identifying the locally assigned address of each device in the external device list.

[0149] According to one implementation, a non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of an electronic device capable of operating in a wireless charging system having at least first and second additional electronic devices, the electronic device inductively coupled to the first additional electronic device without being inductively coupled to the second additional electronic device, and the electronic device including at least one coil configured to receive a wireless power signal from the first additional electronic device and a rectifier circuit configured to convert the wireless power signal to a direct current power, the one or more programs including instructions for assigning an address to the first and second additional electronic devices and utilizing the at least one coil to communicate with the first and second additional electronic devices using the address.

[0150] According to another implementation, the one or more programs further include instructions for including the address for the first and second additional electronic devices in an internal device list including the first and second additional electronic devices.

[0151] According to another implementation, the address identifies an inductive coupling path within the wireless charging system.

[0152] The foregoing is merely illustrative and various modifications can be made to the described embodiments. Such modifications can be independently implemented or combined in any combination.

Claims

1. An electronic device capable of operating in a wireless charging system having at least a first additional electronic device and a second additional electronic device, wherein the electronic device is inductively coupled to the first additional electronic device and not inductively coupled to the second additional electronic device, and wherein the first additional electronic device is inductively coupled to both the electronic device and the second additional electronic device, the electronic device comprising: at least one coil configured to receive a wireless power signal from the first additional electronic device; a rectifier circuit configured to convert the wireless power signal to a direct current power; and a control circuit configured to: assign addresses to the first and second additional electronic devices; and communicate with the first and second additional electronic devices using the addresses using the at least one coil.

2. The electronic device of claim 1, wherein the control circuit is configured to assign the addresses to the first and second additional electronic devices during a network discovery process.

3. The electronic device of claim 2, wherein the control circuit is configured to, during the network discovery process: generate an internal device list comprising one or more devices to which the electronic device is inductively coupled.

4. The electronic device of claim 3, wherein the internal device list comprises a device type and an address for each of the one or more devices to which the electronic device is inductively coupled.

5. The electronic device of claim 4, wherein the address assigned to each of the one or more devices is equal to an identifier for an inductive link through which the electronic device is inductively coupled to the respective device.

6. The electronic device of claim 5, wherein the control circuit is configured to, during the network discovery process: receive an external device list from the first additional electronic device, wherein the external device list identifies the second additional electronic device; and in response to receiving the external device list from the first additional electronic device, add the second additional electronic device to the internal device list.

7. The electronic device of claim 6, wherein the second additional electronic device has a first address in the external device list, wherein the second additional electronic device has a second address in the internal device list, and wherein the second address is different than the first address.

8. The electronic device of claim 7, wherein the control circuit is configured to append an identifier for an inductive link on which the external device list was received to the first address to produce the second address. ​ 9. The electronic device of claim 6, wherein the external device list identifies a third additional electronic device inductively coupled to the second additional electronic device and not inductively coupled to the first additional electronic device, and wherein the control circuit is configured to add the third additional electronic device to the internal device list.

10. The electronic device of claim 1, wherein the address identifies an inductive coupling path within the wireless charging system.

11. The electronic device of claim 1, wherein each address has a multi-digit number and wherein each digit identifies a respective inductive coupling path within the wireless charging system.

12. The electronic device of claim 1, wherein the control circuit is configured to include the address for the first and second additional electronic devices in an internal device list that includes the first and second additional electronic devices.

13. An electronic device capable of operating in a wireless charging system having at least a first additional electronic device and a second additional electronic device, the electronic device comprising: a wireless power circuit including at least one coil; and a control circuit configured to exchange packets with the first additional electronic device and the second additional electronic device using the at least one coil, wherein the packets include locally assigned addresses that identify inductive coupling paths within the wireless charging system.

14. The electronic device of claim 13, wherein the control circuit is configured to, during a network discovery process: receive an external device list from the first additional electronic device; add a new device from the external device list to an internal device list; and send the internal device list to the second additional electronic device.

15. The electronic device of claim 14, wherein the new device has a first address in the external device list from the first additional electronic device, wherein the new device has a second address in the internal device list, and wherein the second address is different than the first address.

16. The electronic device of claim 15, wherein the control circuit is configured to add a digit representing an inductive coupling path to the first address to obtain the second address.

17. The electronic device of claim 14, wherein the list of external devices received from the first additional electronic device includes: a first plurality of bytes identifying a device type of each device in the external device list; and a second plurality of bytes identifying the locally assigned address of each device in the external device list.

18. A non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of an electronic device capable of operating in a wireless charging system with at least a first additional electronic device and a second additional electronic device, wherein the electronic device is inductively coupled to the first additional electronic device and not inductively coupled to the second additional electronic device, wherein the first additional electronic device is inductively coupled to both the electronic device and the second additional electronic device, and wherein the electronic device includes at least one coil configured to receive a wireless power signal from the first additional electronic device and a rectifier circuit configured to convert the wireless power signal to a direct current power, the one or more programs comprising instructions for: allocating addresses to the first additional electronic device and the second additional electronic device; and communicating with the first additional electronic device and the second additional electronic device using the addresses with the at least one coil.

19. The non-transitory computer-readable storage medium of claim 18, wherein the one or more programs further comprise instructions for: including the addresses of the first additional electronic device and the second additional electronic device in an internal device list that includes the first additional electronic device and the second additional electronic device.

20. The non-transitory computer-readable storage medium of claim 18, wherein the addresses identify inductive coupling paths within the wireless charging system.

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