Wireless charging system with switchable magnetic core

Abstract

An electronic device in a wireless power system can operate with a removable accessory, such as a housing. When the device is coupled to the housing, it can transmit wireless power to, from, or through the housing. The device may have coplanar power transmission and power reception coils. The removable accessory may have an embedded switchable ferrimagnetic core and coils overlapping the switchable ferrimagnetic core. The switchable ferrimagnetic core can operate in a first state, wherein the switchable ferrimagnetic core is unsaturated. The switchable ferrimagnetic core can operate in a second state, wherein the switchable ferrimagnetic core is saturated by a magnetic field from a permanent magnet in the wireless power transmission device. In the second state, the switchable ferrimagnetic core may have a lower permeability and a higher magnetic reluctance than in the first state.

Description

[0001] This application claims priority to U.S. Patent Application No. 17 / 179,603, filed February 19, 2021, and U.S. Provisional Patent Application No. 63 / 041,729, filed June 19, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates in general to power systems, and more specifically to wireless power systems for charging electronic devices. Background Technology

[0003] In a wireless charging system, a wireless power transmission device, such as a charging pad, wirelessly transmits power 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 AC wireless power signals from the wireless charging pad. The rectifier circuit converts the received signal into DC power. Summary of the Invention

[0004] A wireless power system may 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 may include a coil and wireless power transmitting circuitry coupled to the coil. The wireless power transmitting circuitry may be configured to transmit wireless power signals using the coil. The wireless power receiving device may include a coil configured to receive wireless power signals from the wireless power transmitting device and a rectifier circuitry configured to convert the wireless power signals into DC power. The wireless power transmitting and receiving device may include at least one coil, and both the wireless power transmitting circuitry and the wireless power receiving circuitry.

[0005] Devices in a wireless power system can operate with removable accessories such as housings. When an electronic device is coupled to a housing, it can transmit or receive wireless power through the housing. When an electronic device is coupled to a housing, it can also transmit or receive wireless power to or from the housing. The housing may have a split shape with a front cover portion that covers a display for the electronic device.

[0006] The removable accessory may have an embedded switchable ferrimagnetic core and a coil overlapping the switchable ferrimagnetic core. In one scenario, the removable accessory may be coupled to a device without being coupled to a separate wireless power transmission device (such as a wireless charging pad). In this scenario, the switchable ferrimagnetic core may be able to operate in a first state, wherein the switchable ferrimagnetic core is unsaturated and has high permeability and low magnetic reluctance. In the first state, the switchable ferrimagnetic core may direct magnetic flux received from the device to the coil embedded in the removable accessory.

[0007] When the removable accessory is both coupled to the device and placed on the wireless charging pad, the wireless charging pad can transmit wireless power to the device via the removable accessory. In this scenario, the switchable ferrimagnetic core can operate in a second state, wherein the switchable ferrimagnetic core is saturated by a magnetic field from a permanent magnet in the wireless charging pad. In the second state, the switchable ferrimagnetic core can have a lower permeability and a higher magnetic reluctance than in the first state. The switchable ferrimagnetic core can have a saturation magnetic flux density, which is selected such that the switchable ferrimagnetic core has different magnetic reluctances depending on the presence of the wireless power transmission device and its permanent magnet. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of an exemplary wireless power system based on the implementation plan.

[0009] Figure 2 This is a circuit diagram of an exemplary wireless power transmission and reception circuit according to one implementation scheme.

[0010] Figure 3 This is a top view of an illustrative removable housing with a front cover portion according to one embodiment.

[0011] Figure 4 It is based on an implementation plan. Figure 3 An illustrative side view of the removable housing cross-section.

[0012] Figure 5 This is a perspective view of an exemplary wireless charging system according to one embodiment, wherein portable electronic devices and removable accessories are located on the charging surface of a wireless power transmission device.

[0013] Figure 6 This is a cross-sectional side view of an exemplary wireless charging system according to one embodiment, wherein a portable electronic device is located on the charging surface of a wireless power transmission device.

[0014] Figure 7 This is a cross-sectional side view of an exemplary wireless charging system according to one embodiment, in which a portable electronic device is coupled to a removable accessory.

[0015] Figure 8 This is a cross-sectional side view of an exemplary wireless charging system according to one embodiment, wherein a portable electronic device and a removable accessory are located on the charging surface of a wireless power transmission device.

[0016] Figure 9 This is a top view of the rear of an exemplary removable accessory having a toroidal switchable ferrimagnetic core according to one embodiment.

[0017] Figure 10This is a top view of an exemplary portable electronic device having a transmitting coil and a receiving coil according to one embodiment, the transmitting coil having a central opening and the receiving coil being located within the central opening. Detailed Implementation

[0018] A wireless power system may include one or more electronic devices that transmit wireless power, one or more electronic devices that receive wireless power, and one or more electronic devices that simultaneously transmit and receive wireless power. The wireless power transmitting device may be, for example, a wireless charging pad or wireless charging dish. The wireless power receiving device may be, for example, a wristwatch, a cellular phone, a tablet, a laptop computer, or other electronic equipment. The wireless power transmitting and receiving devices may be the housing of an electronic device (e.g., the housing of a cellular phone) or other types of electronic devices. The wireless power transmitting device can wirelessly transmit power to the wireless power receiving device. The wireless power receiving device uses the power from the wireless power transmitting device to power its device and charge its internal battery.

[0019] One or more wireless power transmission coils are used to transmit wireless power from a wireless power transmission device to a wireless power receiving device. The wireless power receiving device has one or more wireless power receiving coils coupled to a rectifier circuit that converts the received wireless power signal into DC power.

[0020] 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.

[0021] Wireless power transmission device 12 includes control circuitry 16. Wireless power receiving device 24 includes control circuitry 30. Wireless power transmission 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.

[0022] The control circuitry in system 8 can be configured to perform operations within system 8 using hardware (e.g., dedicated hardware or circuitry), firmware, and / or software. Software code used to perform operations within system 8 is stored on a non-transitory computer-readable storage medium (e.g., a tangible computer-readable storage medium) in the control circuitry 8. Software code may sometimes be referred to as software, data, program instructions, commands, or code. The non-transitory computer-readable storage medium may include non-volatile memory such as non-volatile random access memory (NVRAM), one or more hard disk drives (e.g., disk drives or solid-state drives), one or more removable flash drives, or other removable media. The software stored on the non-transitory computer-readable storage medium can be executed on the processing circuitry of control circuits 16, 30, and / or 78. The processing circuitry may include an application-specific integrated circuit (ASIC) with processing circuitry, one or more microprocessors, a central processing unit (CPU), or other processing circuitry.

[0023] The power delivery device 12 can be a standalone power adapter (e.g., a wireless charging pad or charging stand including power adapter circuitry), a wireless charging pad or stand coupled to a power adapter or other equipment via a cable, a portable device, equipment already integrated into furniture, vehicles, or other systems, a removable battery case, or other wireless power delivery equipment. The wireless power delivery device 12 is an exemplary configuration of a wireless charging pad or wireless charging tray, sometimes described herein as an example.

[0024] The power receiving device 24 can be a portable electronic device, such as a wristwatch, cell phone, laptop computer, tablet computer, accessories such as earphones, or other electronic equipment. The power transmitting device 12 can be coupled to a wall socket (e.g., an AC power source), may have a battery for power supply, and / or may have another power source. The power transmitting device 12 may have an AC-DC power converter, such as an AC-DC power converter 14, for converting AC power from the wall socket or other power source into DC power. The DC power can be used to power the control circuitry 16. During operation, the controller in the control circuitry 16 uses the power transmitting circuitry 52 to transmit wireless power to the power receiving circuitry 54 of the device 24. For simplicity, this document describes an example of the power transmitting device 12 transmitting wireless power to the power receiving device 24. However, it should be understood that during wireless power transfer operation, the power transmitting and receiving devices 18 can replace one or both of the power transmitting and receiving devices.

[0025] The power delivery circuit 52 may have a switching circuit (e.g., an inverter circuit 61 formed by transistors) that is turned on or off based on a control signal provided by the control circuit 16 to generate an AC current signal through one or more wireless power delivery coils, such as wireless power delivery coil 36. These coil drive signals cause coil 36 to deliver wireless power. Coil 36 may be arranged as a planar coil array or as a cluster of coils. In some arrangements, device 12 (e.g., a charging pad, charging stand, etc.) may have only a single coil. In other arrangements, the wireless charging device may have multiple coils (e.g., two or more coils, 5-10 coils, at least 10 coils, 10-30 coils, less than 35 coils, less than 25 coils, or other suitable number of coils).

[0026] When AC current passes through one or more coils 36, it generates an alternating electromagnetic (e.g., magnetic) field (wireless power signal 44), which is received by one or more corresponding receiver coils, such as one or more coils 48 in power receiving device 24. In other words, one or more of coils 36 are inductively coupled to one or more of coils 48. Device 24 may have a single coil 48, at least two coils 48, at least three coils 48, at least four coils 48, or other suitable number of coils 48.

[0027] When an alternating electromagnetic field (sometimes referred to as magnetic flux) is received by coil 48 (e.g., when magnetic flux passes through coil 48), a corresponding alternating current is induced in coil 48. The AC signal used to transmit wireless power can have any suitable frequency (e.g., 100kHz-250kHz, etc.). A rectifier circuit, such as rectifier circuit 50 (which includes rectifier components, such as synchronously rectified metal-oxide-semiconductor transistors arranged in a bridge network), converts the AC signal (the received AC signal associated with electromagnetic signal 44) received from one or more coils 48 into a DC voltage signal for powering device 24.

[0028] The DC voltage generated by rectifier circuit 50 (sometimes referred to as rectifier output voltage Vrect) can be used to charge batteries such as battery 58 and to power other components in device 24. For example, device 24 may include input-output device 56. Input-output device 56 may include input devices for acquiring user input and / or performing environmental measurements, and may include output devices for providing output to the user. For example, input-output device 56 may include a display for creating visual output, a speaker for presenting output as an audio signal, LED status indicators and other light-emitting components for emitting light to provide status information and / or other information to the user, tactile devices for generating vibrations and other tactile outputs, and / or other output devices. Input-output device 56 may also include sensors for acquiring input from the user and / or for measuring the surrounding environment of system 8. Exemplary sensors that may be included in input-output device 56 include three-dimensional sensors (e.g., three-dimensional image sensors such as structured light sensors that emit a light beam and use a two-dimensional digital image sensor to acquire image data for a three-dimensional image from the light spot generated when the light beam illuminates a target; binocular three-dimensional image sensors that use two or more cameras in a binocular imaging arrangement to acquire three-dimensional images; three-dimensional lidar (light detection and ranging) sensors; three-dimensional radio frequency sensors; or other sensors that acquire 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 needed) on light sources emitting one or more light beams, wherein the image sensor is used to track the one or more light beams after the user's eye reflects the light beam), and touch sensors. Devices include: 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 performing spectral and other measurements on a target object (e.g., by emitting light and measuring the reflected light), microphones for acquiring voice commands and other audio input, distance sensors, motion, position, and / or orientation sensors configured to acquire information about motion, position, and / or orientation (e.g., accelerometers, gyroscopes, compasses, and / or inertial measurement units including all of these sensors or a subset of these sensors), sensors such as buttons for detecting button press input, joysticks with sensors for detecting joystick movement, keyboards, and / or other sensors. Device 12 may optionally have one or more input-output devices 70 (e.g., input devices and / or output devices of the type described in Input-Output Device 56).Device 18 may optionally have one or more input-output devices 92 (e.g., input devices and / or output devices of the type described in input-output device 56).

[0029] Devices 12, 18, and / or 24 can perform wireless communication using in-band or out-of-band communication. Device 12 may, for example, have a wireless transceiver circuit 40 that uses an antenna to wirelessly transmit out-of-band signals (e.g., to device 18 or device 24). Wireless transceiver circuit 40 can be used to wirelessly receive out-of-band signals from device 18 or 24 using an antenna. Device 24 may have a wireless transceiver circuit 46 for transmitting out-of-band signals. Receiver circuitry in wireless transceiver 46 can use an antenna to receive out-of-band signals. Device 18 may have a wireless transceiver circuit 80 for transmitting out-of-band signals. Receiver circuitry in wireless transceiver 80 can use an antenna to receive out-of-band signals. Wireless transceiver circuits 40, 46, and 80 can also be used for in-band transmission between devices 12, 24, and 18 using coils 36, 48, and 90.

[0030] Frequency shift keying (FSK) and / or amplitude shift keying (ASK) can be used to transmit data within a band between devices 12, 18, and 24. Power can be wirelessly transmitted during these FSK and ASK transmissions.

[0031] It is expected that power transmission device 12, power transmission and receiving device 18, and power receiving device 24 can convey information such as received power and battery charging status to control wireless power delivery. However, this process does not need to involve the transmission of personally identifiable information. Out of due care, it is important to note that, to some extent, if any implementation of this charging technology involves the use of personally identifiable information, the implementer should follow privacy policies and practices generally considered to meet or exceed industry or governmental requirements for protecting user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly explained to the user.

[0032] The control circuit 16 includes an external object measurement circuit 41, which can be used to detect external objects on the charging surface of the housing of the device 12 (e.g., on top of the charging pad, or, if desired, to detect objects adjacent to the coupling surface of the charging dock). The charging surface may be formed by a flat outer surface of the upper housing wall of the device 12 or may have other shapes (e.g., concave or convex). In an arrangement in which the device 12 forms a charging pad, the charging pad may have a surface shape adapted to the shape of the device 24. If desired, the charging dock or other device 12 may have a magnet (sometimes referred to as a magnetic alignment structure) that removably attaches the device 12 to the device 24 during the alignment of the coil 48 with the coil 36 for effective wireless charging.

[0033] Circuit 41 can detect foreign objects such as coils, paperclips, and other metallic objects, and can detect the presence of wireless power receiving device 24 (e.g., circuit 41 can detect the presence of one or more coils 48 and / or the presence of a magnetic core material associated with coil 48). During object detection and characterization operations, the external object (foreign object) measurement circuit 41 can be used to measure coil 36, such as Q factor measurement, resonant frequency measurement, and / or inductive measurement, which can indicate the presence of coil 48 and / or the presence of foreign objects such as coins or paperclips. The measurement circuit can also be used to perform sensor measurements using capacitive sensors, can be used to perform temperature measurements, and / or can be otherwise used to acquire information indicating the presence of foreign objects or other external objects (e.g., device 18 or 24) on device 12.

[0034] In some configurations, the control circuitry of device 12 (e.g., circuitry 41 and / or other control circuitry 16) can perform power counting for a foreign object detection scheme. Using this method, device 12 (e.g., via in-band communication) receives information from device 24 indicating the amount of power (e.g., 4.5W) wirelessly received by device 24. Device 12 knows how much power (e.g., 5.0W) is being transmitted (e.g., because device 12 knows the magnitude of the signal used to drive coil 36 from inverter 61). By comparing the transmitted power (e.g., 5.0W) with the received power (e.g., 4.5W), device 12 can determine whether the wireless power is dissipated due to eddy currents flowing in the foreign object. If the dissipated power (e.g., 0.5W in this example) is greater than a predetermined threshold amount, or if the efficiency of the wireless power transfer process is lower than expected, device 12 can determine 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 circuitry 41.

[0035] In some implementations, the measurement circuit 41 of the control circuit 16 includes signal generator circuitry (e.g., oscillator circuitry for generating AC probe signals at one or more probe frequencies, pulse generators for producing pulses that make the pulse response measurable) and / or uses the transmission of a wireless power signal from device 12 to energize the coils in system 8. Circuit 41 may also include circuitry for measuring the response of system 8 (e.g., analog-to-digital converter circuitry, filters, analog combiners, digital processing circuitry, etc.).

[0036] The power transmission and reception device 18 may be a wireless charging pad or charging tray coupled to a power adapter or other equipment via a cable; it may be equipment already integrated into furniture, vehicles, or other systems; it may be a removable battery casing; or it may be a portable electronic device such as a watch, cell phone, laptop computer, tablet computer, accessory such as earphones, or other electronic equipment. The power transmission and reception device 18 is capable of simultaneously transmitting and receiving wireless power. Therefore, the power transmission and reception device 18 may include a power transmission component, similar to the power transmission device 12. The power transmission and reception device 18 may also include a power receiving component, similar to the power receiving device 24.

[0037] The power transmission and reception device 18 may have an AC-to-DC power converter, such as an AC-DC power converter 96, for converting AC power from a wall socket or other power source into DC power. The DC power may be used to power control circuitry 78. Control circuitry 78 includes wireless transceiver circuitry 80 for in-band communication (using coil 90) and out-of-band communication (using an antenna). Control circuitry 78 may also optionally include measurement circuitry 82 (e.g., a measurement circuit of the type described in conjunction with measurement circuitry 41).

[0038] The wireless power circuitry 84 in device 18 may include both an inverter 86 and a rectifier 88. The inverter circuitry 86 (e.g., formed of transistors) may be switched on and off based on control signals provided by control circuitry 78 to generate AC current signals through one or more coils, such as coil 90. These coil drive signals cause coil 90 to transmit wireless power. Coil 90 may be arranged as a planar coil array or as a cluster of coils. In some arrangements, device 18 may have only a single coil. In other arrangements, device 18 may have multiple coils (e.g., two or more coils, 5-10 coils, at least 10 coils, 10-30 coils, fewer than 35 coils, fewer than 25 coils, or other suitable number of coils).

[0039] When an AC current passes through one or more coils 90, it generates an alternating electromagnetic (e.g., magnetic) field (wireless power signal 44), which is received by one or more corresponding receiver coils, such as coil 48 in 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.

[0040] The power transmission and reception device 18 can also receive wireless power (e.g., from the power transmission device 12). Coil 90 can receive an AC electromagnetic field from the transmission coil 36, thereby generating a corresponding AC current in coil 90. A rectifier circuit, such as rectifier circuit 88, which includes rectifier components such as synchronously rectified metal-oxide-semiconductor transistors arranged in a bridge network, converts the AC signal (the received AC signal associated with electromagnetic signal 44) received from one or more coils 90 into a DC voltage signal for powering device 18. The DC voltage generated by rectifier circuit 88 can be used to charge a battery, such as battery 94, and can also be used to power other components in device 18.

[0041] Figure 1 The depiction of the alternating electromagnetic field between each type of device is merely illustrative (to show the possible types of inductive coupling). In practice, the alternating electromagnetic field will only be transmitted between selected devices within the system. For example, transmission device 12 may transmit power to both device 24 and device 18 (while device 18 does not transmit power to device 18 alone). In another example, transmission device 12 transmits power to device 18, which in turn transmits power to device 24 (without a direct power exchange from device 12 to device 24).

[0042] In some applications, the power transmission and reception device 18 transmits only wireless power (e.g., using inverter 86 and coil 90). In some applications, the power transmission and reception device 18 receives only wireless power (e.g., using rectifier 88 and coil 90). In some applications, the power transmission and reception device simultaneously receives and transmits wireless power. When simultaneously receiving and transmitting wireless power, device 18 may optionally perform both the power transmission and power reception operations associated with inverter 86 and rectifier 88 (e.g., device 18 uses the rectifier to charge the battery and operate the device, and independently uses the inverter to transmit the required amount of power). Alternatively, device 18 may relay the received power signal without rectifying the power. Device 18 may include only one coil for both wireless power transmission and wireless power reception. Alternatively, device 18 may have at least one dedicated wireless power transmission coil and at least one dedicated wireless power reception coil. Device 18 may have multiple coils, all of which are capable of both wireless power transmission and wireless power reception. The different coils in device 18 can be optionally shorted together in different operating modes.

[0043] Figure 2 This is a circuit diagram of an exemplary wireless charging circuit for System 8. The wireless charging circuitry for power transmission device 12 and power receiving device 24 is shown. However, it should be understood that device 18 may have corresponding components for both power transmission and power reception, and may be used in place of device 12 and / or device 24 if needed. Figure 2 As shown, circuit 52 may include inverter circuitry such as one or more inverters 61 or other drive circuitry that generates a wireless power signal transmitted through an output circuitry including one or more coils 36 and capacitors such as capacitor 71. In some embodiments, device 12 may include multiple individually controlled inverters 61, each providing a drive signal to a corresponding coil 36. In other embodiments, a switching circuitry is used to share an inverter 61 among multiple coils 36.

[0044] During operation, control signals for one or more inverters 61 are provided by control circuit 16 at control input 74. Figure 2The example shows a single inverter 61 and a single coil 36, but multiple inverters 61 and multiple coils 36 can be used if desired. In a multi-coil configuration, switching circuitry (e.g., multiplexer circuitry) can be used to couple a single inverter 61 to multiple coils 36 and / or each coil 36 can be coupled to a corresponding inverter 61. During wireless power transfer operation, transistors in one or more selected inverters 61 are driven by AC control signals from control circuitry 16. The relative phase between the inverters can be dynamically adjusted. For example, a pair of inverters 61 can produce in-phase or out-of-phase (e.g., 180-degree out-of-phase) output signals.

[0045] An inverter 61 (e.g., a transistor or other switch in circuit 52) ​​is used to apply a drive signal, causing an output circuit formed by a selected coil 36 and a capacitor 71 to generate an alternating electromagnetic field (signal 44), which is received by a wireless power receiving circuit 54, which is formed by one or more coils 48 and one or more capacitors 72 in device 24.

[0046] If needed, the control circuit 16 can adjust the relative phase between the drive coils 36 (e.g., the phase of one coil in the coils 36 that is driven relative to another adjacent driven coil in the coils 36) to help enhance wireless power transfer between device 12 and device 24. A rectifier circuit 50 is coupled to one or more coils 48 and converts the received power from AC to DC, providing a corresponding DC output voltage Vrect at the rectifier output terminal 76 for powering load circuitry in device 24 (e.g., for charging battery 58, for powering a display and / or other input-output devices 56, and / or for powering other components). A single coil 48 or multiple coils 48 may be included in device 24.

[0047] As previously described, in-band transmission using coils 36 and 48 can be used to transfer (e.g., transmit and receive) information between device 12 and device 24. In one exemplary configuration, frequency shift keying (FSK) is used to transfer in-band data from device 12 to device 24, and amplitude shift keying (ASK) is used to transfer 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 transmission / reception device 12 / 24 or a power receiving and transmission 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 transmission / reception device 12 / 24 or a power receiving and transmission device 18).

[0048] During these FSK and ASK transmissions, power can be wirelessly delivered from device 12 to device 24. Although power delivery circuitry 52 drives an AC signal to one or more coils of coil 36 at a power delivery frequency to generate signal 44, wireless transceiver circuitry 40 can use FSK modulation to modulate the power delivery frequency driving the AC signal, and thereby modulate the frequency of signal 44. In device 24, coil 48 is used to receive signal 44. Power receiving circuitry 54 uses the received signal on coil 48 and rectifier 50 to generate DC power. Simultaneously, wireless transceiver circuitry 46 monitors the frequency of the AC signal passing through one or more coils 48 and uses FSK demodulation to extract the transmitted in-band data from signal 44. This method allows FSK data (e.g., FSK data packets) to be transmitted in-band from device 12 to device 24 via coils 36 and 48, while simultaneously using coils 36 and 48 to wirelessly deliver power from device 12 to device 24.

[0049] In-band communication between device 24 and device 12 can utilize ASK modulation and demodulation techniques. Wireless transceiver circuitry 46 transmits in-band data to device 12 by using a switch (e.g., one or more transistors coupling coil 48 in transceiver 46) to modulate the impedance of power receiving circuitry 54 (e.g., coil 48). This, in turn, modulates the amplitude of signal 44 and the amplitude of the AC signal passing through one or more coils 36. Wireless transceiver circuitry 40 monitors the amplitude of the AC signal passing through one or more coils 36 and uses ASK demodulation to extract the transmitted in-band data from these signals transmitted by wireless transceiver circuitry 46. ASK communication allows ASK data bits (e.g., ASK data packets) to be transmitted in-band from device 24 to device 12 via coils 48 and 36, while power is wirelessly transmitted from device 12 to device 24 using coils 36 and 48.

[0050] The examples of FSK modulation for transmitting in-band data from power transmission device 12 to power receiving device 24 and ASK modulation for transmitting in-band data from power receiving device 24 to power transmission device 12 are merely illustrative. In general, any desired communication technology can be used to transmit information from power transmission device 12 to power receiving device 24 and from power receiving device 24 to power transmission device 12.

[0051] The power transmission frequency used for wireless power transmission can be a predetermined frequency, such as 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 frequencies. In some configurations, the power transmission frequency can be negotiated in communication between devices 12 and 24. In other configurations, the power transmission frequency can be fixed.

[0052] It has been described that power can be transmitted between devices simultaneously while using in-band communication for data transfer between devices. In other words, in some examples, in-band communication can rely on modulation of the power-transmitted signal (e.g., modulation of the power-transmitted frequency or modulation of the amplitude of the signal at the power-transmitted frequency). However, other communication techniques that do not rely on modulation of the power-transmitted signal can be used. For example, a signal (sometimes referred to as an in-band signal) can be transmitted between coils in the system at a frequency different from the power-transmitted frequency. Signals transmitted using coils (e.g., coils 36, 48, and 90) at the same or a different frequency than the power-transmitted frequency can be considered in-band signals.

[0053] Furthermore, it should be noted that in-band communication may occur between devices before they agree on power transfer rates, power delivery rates, etc. After initial detection and inductive coupling, devices may undergo a handshake process to determine compatibility, negotiate power transfer frequencies, negotiate power delivery rates, etc. During this process, in-band communication may involve FSK and / or ASK modulation of the signal transmitted using a coil. Therefore, wireless power is transferred during this process. This is advantageous because it allows devices to complete the handshake process even if the power receiving device has little or no remaining battery power. Even if the final negotiation between devices does not result in continuous wireless power transmission, this transmission of wireless power during in-band communication can still occur during the handshake process.

[0054] The devices in the wireless charging system 8 can optionally be coupled to a removable accessory such as a housing. The housing may optionally have wireless charging capabilities (e.g., the housing may be able to receive and / or transmit wireless power). Figure 3 It is a top view of an accessory such as a removable cover.

[0055] The removable accessory 102 (sometimes referred to as a removable housing or removable cover) may have any suitable shape that allows the cover 102 to be adapted to another device. The accessory 102 and the device coupled thereto may each function as a power transmission device, a power receiving device, or a power transmission and receiving device. The device held by the accessory 102 may be a portable electronic device, such as a wristwatch, cellular phone, laptop computer, tablet computer, accessories such as earphones, or other electronic equipment.

[0056] exist Figure 3 In the example, cover 102 has a split shape (sometimes referred to as a split cover) with a rear portion 102R and a front portion 102F. The rear portion 102R may have a rectangular recess with a rear wall surrounded by a peripheral sidewall 102W and / or other suitable coupling structures (bands, clips, sleeves, corner recesses, etc.), which allows cover 102 to accommodate and couple to additional equipment.

[0057] A portion of the cover 102 along the folding axis 122 between the rear portion 102R and the front portion 102F may have a hinge structure (e.g., a flexible cover material that acts as a hinge or other hinge structure, coupling portions 102F and 102R while allowing these portions to rotate relative to each other). In some configurations, additional flexible portions may be provided. For example, the front portion 102F may have one or more flexible bands. Each flexible band allows additional folds to be formed in the cover 102 (e.g., manipulating the cover into one or more support configurations and supporting the additional device at a desired angle when the cover 102 is coupled to an additional device). Each flexible band may extend parallel to the folding axis 122 from one side of the front portion 102F to the other side of the front portion 102F.

[0058] When it is desired to protect additional equipment within the cover 102, the equipment (e.g., the housing of the equipment) may be press-fitted into a recess formed by the sidewalls 102W and / or rear wall of the cover 102, coupled to the cover 102 using magnets, clips, or straps, or otherwise coupled to the cover 102. The cover 102 may be formed of fabric, leather, polymer, other materials, and / or combinations of these materials.

[0059] As previously mentioned, in some embodiments, cover 102 may include a coil for transmitting and / or receiving wireless power. For example, cover 102 may be a wireless power receiving device (e.g., Figure 1 The device 24 in the cover has a receiving coil 48 in region 178 on the rear portion 102R of the cover. The receiving coil 48 in region 178 can be aligned with a transmitting coil in the device coupled to the accessory 102. When the accessory 102 is coupled to the accessory device, the accessory device can transmit wireless power to the receiving coil in region 178 of the cover 102.

[0060] Incorporating a wireless power receiving coil within the cover allows the cover to charge an internal battery, power components within the cover (e.g., input-output components such as a keyboard), and / or provide wireless power to additional accessories. For example, cover 102 can be configured to charge an electronic pen (e.g., to provide input on a display in an additional device). In this type of arrangement, cover 102 can be a power transmission and reception device (e.g., Figure 1 Device 18 in the cover 102 may include a wireless power receiving coil in region 178 and a separate wireless power transmitting coil. The separate wireless power transmitting coil may optionally be located in a portion of the cover that is different from region 178 (e.g., in a region along the folding axis 122, in one sidewall of sidewall 102W, or in another desired location within the cover).

[0061] Figure 4This is a cross-sectional side view showing a device 100 held in a removable cover 102. The device 100 may have a housing 164. The housing 164 may be formed of plastic, glass, ceramic, fiber composite material, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or any combination of two or more of these materials. In an exemplary example, the device 100 is a power transmission and reception device (e.g., Figure 1 Device 102 can be a power receiving device that receives wireless power from device 100 (e.g., device 18). Figure 1 (Device 24 in the original text). Alternatively, device 102 may also be a power transmission and reception device that receives wireless power from device 100 and transmits wireless power to an additional accessory device such as a stylus. In yet another possible configuration, device 102 may be able to transmit wireless power to device 100.

[0062] exist Figure 4 In this configuration, the front portion 102F of the cover 102 folds down and covers the front of the device 100. Therefore, the front portion 102F of the cover 102 covers the display in the device 100. This protects the display from damage. As previously mentioned, the cover 102 may include a wireless power receiving coil in the rear portion 102R, which is configured to receive wireless power from the device 100. In other arrangements, the device 100 may need to transmit and / or receive wireless charging signals through the cover 102. For example, the device 100 may be coupled to the cover 102 and placed on a wireless charging pad. The wireless charging pad can transmit wireless power signals to the device 100 through the cover 102. In this case, it is desirable that the cover does not interfere with the wireless power transmission operation performed through the cover.

[0063] Figure 3 and Figure 4 The example of the removable housing 102 is merely illustrative; the removable housing is a removable cover having a cover portion (102F) configured to fold over and cover the display of the device 100. In some arrangements, the front cover portion 102F may be omitted from the removable housing.

[0064] For example, the removable housing may consist only of a rear portion (e.g., a rear outer housing wall configured to cover device 100, sometimes referred to as the rear wall) and side walls (e.g., four peripheral side walls extending from the rear wall). Side walls (e.g., Figure 3The sidewalls 102W of the removable housing may extend perpendicularly to the rear portion of the removable housing. These sidewalls may form recesses configured to receive and secure the device 100 within the removable housing. When it is desired to protect the device 100 within the removable housing, the device 100 (e.g., the housing 164 of the device 100) may be press-fitted into the recesses formed by the sidewalls of the removable housing, coupled to the removable housing using magnets, clips, or straps, or otherwise coupled to the removable housing. The removable housing (excluding the front cover portion) may be formed of fabric, leather, polymer, metal, other materials, and / or combinations of these materials.

[0065] Generally, wireless power signals can be transmitted to or from various parts of housing 102. Wireless power signals can also be transmitted through housing 102 at any desired location. In one example, housing 102 may be a power transmission and reception device including a power receiving coil in the rear wall. Housing 102 may also include a power transmission coil in another desired area (e.g., a peripheral sidewall). This example is merely illustrative, and other arrangements for transmitting wireless power to, from, or through housing 102 may be used if desired.

[0066] The wireless power circuitry in each device of a wireless charging system can be designed to adapt to multiple different charging scenarios. Figure 4 In one scenario, an electronic device, such as a tablet or cellular phone (e.g., device 100), is coupled to a removable accessory. In this scenario, the electronic device can transmit wireless power to the removable accessory (e.g., enabling the removable accessory to then provide power to a stylus, power internal components, etc.).

[0067] In another scenario, device 100 can be placed on a power transmission device (without removable accessories). Figure 5 In another scenario, device 100 can be both coupled to removable accessory 102 and placed on a power transmission device. In this scenario, power transmission device 104 can transmit wireless power to device 100 and / or to accessory 102 itself via accessory 102.

[0068] Similar to combination Figure 1 The power transmission device 104 discussed herein may be a wireless charging pad, a wireless charging stand, a battery case (e.g., a dedicated wireless power transmission device), or another electronic device (e.g., a wireless power transmission and receiving device). This document describes an example of a wireless charging pad as the power transmission device 104. The wireless charging pad 104 may be coupled to a wall outlet (e.g., an AC power source). Using power from this power source, the wireless charging pad 104 may transmit wireless power to one or more devices.

[0069] Figures 6 to 8 This is a cross-sectional side view of a wireless charging system in some of these scenarios. Figure 6 This is a cross-sectional side view of a portable electronic device 100 (e.g., a watch, cell phone, laptop computer, tablet computer, accessory such as earphones, or other electronic equipment) on the surface of the wireless charging pad 104. Device 100 may be a wireless power transmission and reception device (e.g., Figure 1 Device 18), while device 104 is a wireless power transmission device (e.g., Figure 1 Device 12).

[0070] As shown, a power delivery assembly 202 (e.g., part of a power delivery circuit 52) ​​is included within a wireless power delivery device 104. The power delivery assembly (sometimes referred to as an inductive power delivery assembly) includes a magnetic core 203 having a base 204, a first protrusion 206, and a second protrusion 208. A coil 212 is positioned on the magnetic core (e.g., between protrusions 208 and 206). For example, protrusion 206 may have a ring shape concentric with coil 212. Coil 212 may be coupled to an inverter circuit (e.g., Figure 1 The inverter circuit can drive coil 212 to generate magnetic flux. Coil 212 can be formed by winding a single strand of wire, a multi-strand wire with multiple wires connected in parallel, braided wire, Litz wire, conductive ink or conductive traces (such as multilayer traces on a printed circuit board) or other conductive elements suitable for forming a coil.

[0071] A power receiving component 222 is included within device 100. As previously mentioned, device 100 may be as follows: Figure 1 The power transmission and reception device 18 (and the power receiving component 222 may be) Figure 1 (Part of the wireless power circuit 84). The power receiving assembly (sometimes called the inductive power receiving assembly) includes a magnetic core 224. A coil 226 is formed on the magnetic core. The coil 226 can be coupled to a rectifier circuit (e.g., Figure 1 The rectifier circuit (88) converts the AC signal received from the coil 226 into a DC voltage signal to power the device 100. The coil 226 may be formed by winding a single strand of wire, a multi-strand wire with multiple wires connected in parallel, braided wire, Litz wire, conductive ink or conductive traces (such as multilayer traces on a printed circuit board), or other conductive elements suitable for forming a coil.

[0072] Alignment structures such as magnetic alignment structures 214 and 254 may optionally be included in the system. Figure 6As shown, the wireless power transmission device 104 may have a magnetic alignment structure 214. The wireless power transmission and receiving device 100 may have a magnetic alignment structure 254. Each magnetic alignment structure 214 in the transmission device may be magnetically coupled to a corresponding magnetic alignment structure 254 in the receiving device. When the alignment structure 214 in device 104 is coupled to the alignment structure 254 in device 100, the transmission coil 212 may be aligned with the receiving coil 226. Therefore, the magnetic alignment structure ensures the correct alignment of the receiving coil relative to the transmission coil. The magnetic alignment structures 214 and 254 may be permanent magnets (e.g., formed of a hard magnetic material that retains its magnetism over a long period).

[0073] Device 100 may also include a power delivery component 242. The power delivery component (sometimes referred to as an inductive power delivery component) includes a magnetic core 244. A coil 246 is formed on the magnetic core. The coil 246 may be coupled to an inverter circuit (e.g., Figure 1 (Inverter 86 in the circuit). The inverter circuit can drive coil 246 to generate magnetic flux. Coils 246 and 226 may be coplanar and / or magnetic cores 244 and 224 may be coplanar. Coil 246 may be formed by winding a single strand of wire, a multi-strand wire with multiple parallel connections, braided wire, Litz wire, conductive ink or conductive traces (such as multilayer traces on a printed circuit board) or other conductive elements suitable for forming a coil.

[0074] When the device 100 is placed on the charging pad 104 without the removable accessory 102, the transmission component 242 can be disabled (e.g., the coil 246 is not used to transmit wireless power and the device 100 only uses the coil 226 to receive wireless power). However, when the device 100 is coupled to the accessory 102 without the charging pad 104, the receiving component 222 can be disabled (e.g., the coil 226 is not used to receive wireless power and the device 100 only uses the coil 246 to transmit wireless power).

[0075] Figure 6 The magnetic cores (e.g., 203, 224, and 244) can be formed from soft magnetic materials such as ferrites. The cores can have high permeability, allowing them to guide the magnetic field in the system. The example of using ferrite cores is merely illustrative. If desired, other ferromagnetic and / or ferrimagnetic materials such as iron, low-carbon steel, mu-metal (nickel-iron alloy), nanocrystalline magnetic materials, rare earth metals, or other magnetic materials with sufficiently high permeability to guide the magnetic field in the system can be used for one or more cores. The cores are sometimes referred to as ferrimagnetic cores. Cores 203, 224, and 244 can be made as a single piece or from separate pieces. The cores can be molded, sintered, formed by lamination, formed from particles (e.g., ceramic particles) distributed in a polymer, or manufactured by other processes.

[0076] The magnetic cores 203 and 224 improve the coupling between coils 212 and 226 (compared to an arrangement that omits cores 203 and 224). Figure 6 The magnetic core 224 can redirect the received magnetic flux to the coil 226. The magnetic core 224 can have a disc shape or other desired shape.

[0077] Each core can be optimized for its specific function and location within the wireless charging system. Different devices may have different space constraints, resulting in cores being formed from different materials and / or having different geometries. In an exemplary example, coil 226 may be able to operate at a higher maximum power level than coil 246. In other words, coil 226 can be configured to receive wireless power at a first maximum power level. Coil 246 is configured to transmit wireless power at a second maximum power level, lower than the first maximum power level. In one example, the maximum power level of coil 226 may be 10 watts or greater, while the maximum power level of coil 246 may be less than 10 watts. In one example, coil 226 can receive up to 15 watts of power, and coil 246 can transmit up to 5 watts of power. These values ​​for maximum power levels are merely exemplary. In general, each coil can operate at any desired power level.

[0078] Due to differences in associated geometry and power levels, core 244 may have one or more properties different from those of core 224. For example, core 244 may be formed of a different material than core 224 (e.g., a material with a different permeability). Cores 244 and 224 may have different thicknesses. As shown, core 244 has a thickness of 250, while core 224 has a thickness of 252. In one example, thickness 250 may be greater than thickness 252. Cores 244 and 224 may have different permeabilities, different reluctance, or other desired different properties. Cores 244 and 224 may also have different saturation flux densities.

[0079] Figure 7 This is a cross-sectional side view of a portable electronic device 100 coupled to a removable accessory 102 (e.g., device 100 may be as follows). Figure 3 (As shown, it is pressed into attachment 102). Attachment 102 may include a power receiving component 270, which includes a coil 274 for receiving wireless power from device 100 and a switchable magnetic core 272. The power receiving component 270 in attachment 102 can be optimized for different charging scenarios. When attachment 102 is coupled to device 100 in the absence of power transmitter 104 (e.g.) Figure 7 As shown), device 100 is expected to efficiently transmit wireless power to cover 102. However, when an accessory is coupled to device 100 and placed on power transmitter 104 (as shown), Figure 8As shown), it is expected that Annex 102 will not interrupt the power transmission from device 104 to device 100.

[0080] To ensure satisfactory operation of the wireless charging system in both charging scenarios, annex 102 may include a switchable magnetic core. In the absence of the transmission device 104, the switchable magnetic core may have high permeability and therefore low magnetoresistance. In the presence of the transmission device 104, the switchable magnetic core may have low permeability and therefore high magnetoresistance. This can be achieved by selecting a material for the magnetic core 272 with a low saturation magnetic flux density.

[0081] When transmission device 104 is not present, such as Figure 7 As shown, the switchable core 272 (sometimes referred to as the switchable ferrimagnetic core 272) is not exposed to a significant external magnetic field. Therefore, the switchable core 272 does not reach its saturation magnetic flux density and maintains high permeability and low magnetic reluctance. In this state, the switchable core 272 serves as the core for guiding the magnetic field in the system. In other words, in Figure 7 In the middle, coil 274 is inductively coupled to coil 246, and magnetic core 272 redirects the received magnetic flux back to coil 274.

[0082] When transmission device 104 is present, such as Figure 8 As shown, the switchable core 272 is exposed to an external magnetic field from the magnetic alignment structure 214 (which may include one or more permanent magnets). The magnetic field from the magnetic alignment structure 214 can be high enough to saturate the switchable core 272. Once saturated, the permeability of the switchable core 272 decreases and the reluctance of the switchable core increases. Due to the decrease in permeability and the increase in reluctance, the core does not guide the magnetic field in the system. Effectively, saturating the switchable core 272 using the permanent magnet 214 “disconnects” the core 272. This prevents the switchable core 272 from undesirably redirecting magnetic flux through the attachment between coils 212 and 226.

[0083] exist Figure 8 In this configuration, when accessory 102 is inserted between device 104 and device 100, device 104 can transmit wireless power to device 100 through cover 102. This is similar to the inductive coupling of coils 226 and 212 when cover 102 is not present. The magnetic core 224 in device 100 redirects the received magnetic flux to coil 226.

[0084] When Annex 102 is as follows Figure 8 When inserted as shown between device 104 and device 100, the transmission components in device 100 can be disabled. In other words, coils 246 and 274 are... Figure 8The coils 246 and 274 are not inductively coupled. Because coils 246 and 274 are not inductively coupled, the saturated switchable core 272 will not adversely affect the charging efficiency between coils 246 and 274. Furthermore, the saturated switchable core 272 ensures that the inductive coupling between coils 212 and 226 is not interrupted by the switchable core. Coils 212 and 226 can operate at a higher maximum power level than coil 274. Therefore, when the transmission device 104 is present, efficient power transfer between these coils is prioritized by saturating the core 272.

[0085] When the removable accessory 102 is placed on the charging pad 104 (e.g.) Figure 8 As shown), coil 274 can also be inductively coupled to coil 212 in device 104. The power transfer level between coils 212 and 274 may be lower than the power transfer level between coils 212 and 226. This example is merely illustrative. In another possible implementation, in Figure 8 In the arrangement shown, coil 274 may not be inductively coupled to coil 212.

[0086] The coil 274 may be formed by winding a single strand of wire, a multi-strand wire with multiple wires connected in parallel, a braided wire, a Litz wire, conductive ink or conductive traces (such as multi-layer traces on a printed circuit board) or other conductive elements suitable for forming a coil.

[0087] Figure 7 and Figure 8 The switchable magnetic core 272 can be formed from a soft magnetic material such as ferrite. The example of using a ferrite core is merely illustrative. Other ferromagnetic and / or ferrimagnetic materials such as iron, low-carbon steel, mu-metal (nickel-iron alloy), nanocrystalline magnetic materials, rare-earth metals, or other magnetic materials with sufficiently high permeability to guide the magnetic field in the system can be used for the core. The core may sometimes be referred to as a switchable ferrimagnetic core. The core 272 can be a single piece or made from separate pieces. The core can be molded, sintered, formed by lamination, formed from particles (e.g., ceramic particles) distributed in a polymer, or manufactured by other processes.

[0088] Magnetic core 272 can saturate at values ​​less than 2 Tesla (T), less than 1.5T, less than 1.0T, less than 0.8T, less than 0.5T, less than 0.3T, less than 0.2T, and less than 0.1T. Magnetic cores 224, 203, and / or 244 can saturate at values ​​greater than those of magnetic core 272.

[0089] Even when accessory 102 is present between devices 100 and 104, magnetic alignment structures 214 and 254 can be magnetically coupled.

[0090] Figure 9 This is a top view of the rear 102R of the illustrative removable accessory. As shown in the figure, Figure 9 The power receiving component 270 includes a toroidal switchable magnetic core 272. One or more coils 274 are formed on the magnetic core 272. The toroidal switchable magnetic core 272 and the coils 274 can be embedded in a dielectric material for an accessory, such as dielectric material 276 (also in...). Figure 7 and Figure 8 (As shown in the diagram). Coil 274 and core 272 may be completely surrounded and in direct contact with dielectric material 276 (e.g., fabric, leather, polymer, and / or other materials). This example is merely illustrative. In an alternative arrangement, core 272 and coil 274 may be laterally surrounded by dielectric material 276 and may have one or more exposed surfaces on the upper / lower surface of the rear portion 102R. Core 272 and coil 274 may be concentric rings.

[0091] Power received using power receiving component 270 can be used to charge a battery in housing 102, power additional components (e.g., additional input-output components) in housing 102, and / or provide wireless power to additional accessories. As previously discussed, housing 102 may optionally include a power transmission component located elsewhere within the accessory (e.g., in a sidewall) that transmits wireless power to accessories such as an electronic pen. In embodiments where accessory 102 includes a front portion 102F coupled to a rear portion 102R, an optional additional power transmission component may be formed at a flexible hinge structure between the front portion 102F and the rear portion 102R.

[0092] Figure 10 It is an exemplary portable electronic device (such as) having a power receiving component and a power transmitting component. Figures 6 to 8 A top view of device 100. As shown, device 100 includes one or more coils 226 overlapping a magnetic core 224. The magnetic core 224 has a circular shape and may be referred to as disk-shaped or circular. The magnetic core 224 and coils 226 are used to form a power receiving assembly 222, such as... Figures 6 to 8 As shown. Device 100 also includes a power transmission assembly having one or more coils 246 overlapping with the magnetic core 244. The coils 246 and the core 244 may be toroidal. The toroidal coils 246 and the core 244 have a central opening, in which the core 224 and the coil 226 are formed.

[0093] A ring-shaped magnetic alignment structure 254 (e.g., a permanent magnet) may laterally surround the core 244. The alignment structure 254 may have a central opening in which the core 224, coil 226, core 244, and coil 246 are formed. Therefore, in Figure 10In this example, coil 226, coil 246, magnetic core 244, and alignment structure 254 are concentric rings. This example is merely illustrative. Other arrangements may be used if desired (e.g., alignment structure 254 may be formed as two separate permanent magnets on opposite sides of core 244).

[0094] Figures 6 to 10 The examples of power delivery and power receiving components shown are merely illustrative. In general, power delivery and power receiving components can have any desired design. In one possible arrangement, the core of the power delivery and / or power receiving component may have a can-core design (e.g., a package with a toroidal hollow portion to accommodate a coil). In yet another possible arrangement, the power delivery and / or power receiving component may comprise a winding on a strip of ferrite. Any desired core and coil design (e.g., U-shaped core, C-shaped core, E-shaped core, toroidal core, etc.) can be used.

[0095] Generally, each transmit / receive component may have only one coil, two coils, three coils, more than three coils, etc. Each coil may have any desired number of windings. Each component may optionally include a lateral coil (e.g., a coil extending along the base of a magnetic core between two core protrusions). The precise geometry of the coils and cores in devices 100, 102, and 104 can be customized according to the specific design. Device 100 may be designed to specifically cooperate with wireless power transmission device 104. However, this is only illustrative. In some cases, device 100 may not be specifically designed to cooperate with power transmission device 104. Generally, each device may have different coil arrangements, different (or no) magnetic elements (e.g., magnetic cores), different coil and magnetic element sizes, different coil and magnetic element shapes, and other different characteristics.

[0096] According to one embodiment, an electronic device is provided, the electronic device comprising: a first planar wireless charging coil having a winding wound around a central region; a second planar wireless charging coil having a winding positioned in the central region; a first ferrimagnetic core overlapping the first planar wireless charging coil; and a second ferrimagnetic core overlapping the second planar wireless charging coil, the second ferrimagnetic core being positioned to direct received magnetic flux to the second planar wireless charging coil, the second ferrimagnetic core having a different magnetic reluctance than the first ferrimagnetic core.

[0097] According to another embodiment, the first planar wireless charging coil is configured to operate at a first maximum power level, and the second planar wireless charging coil is configured to operate at a second maximum power level greater than the first maximum power level.

[0098] According to another embodiment, the first planar wireless charging coil is configured to transmit a first wireless power signal, and the second planar wireless charging coil is configured to receive a second wireless power signal.

[0099] According to another embodiment, the first planar wireless charging coil is configured to stop transmitting the first wireless power signal when the second planar wireless charging coil receives the second wireless power signal.

[0100] According to another embodiment, the first planar wireless charging coil is configured to transmit the first wireless power signal when the electronic device is coupled to a removable accessory.

[0101] According to another embodiment, the second planar wireless charging coil is configured to receive the second wireless power signal when the electronic device is coupled to the wireless power transmission device.

[0102] According to another embodiment, the second planar wireless charging coil is configured to receive the second wireless power signal when the electronic device is coupled to a removable accessory and a wireless power transmission device.

[0103] According to another embodiment, the first planar wireless charging coil and the second planar wireless charging coil are coplanar.

[0104] According to another embodiment, the first and second ferrimagnetic cores are coplanar.

[0105] According to another embodiment, the first ferrimagnetic core and the second ferrimagnetic core are formed of different materials.

[0106] According to another embodiment, the first ferrimagnetic core and the second ferrimagnetic core have different thicknesses.

[0107] According to another embodiment, the electronic device includes a ring-shaped permanent magnet having a central opening, and the first planar wireless charging coil and the second planar wireless charging coil are positioned in the central opening of the ring-shaped permanent magnet.

[0108] According to one embodiment, an accessory for an electronic device is provided, the electronic device having a first coil configured to transmit a first wireless power signal and a second coil configured to receive a second wireless power signal from a wireless power transmission device, the accessory comprising: a coil configured to receive the first wireless power signal from the first coil in the electronic device when the accessory is coupled to the electronic device; and a ferrimagnetic core overlapping the coil, the ferrimagnetic core operating in the following states: in a first state when the accessory and the electronic device are inductively coupled to the wireless power transmission device, the ferrimagnetic core having a first magnetic reluctance in the first state; and in a second state when the accessory and the electronic device are not inductively coupled to the wireless power transmission device, the ferrimagnetic core having a second magnetic reluctance less than the first magnetic reluctance in the second state.

[0109] According to another embodiment, in the first state, the subferromagnetic core is saturated by a magnetic field from a permanent magnet in the wireless power transmission device.

[0110] According to another embodiment, in the second state, the ferrimagnetic core directs the received magnetic flux to the coil.

[0111] According to another embodiment, the accessory includes a rear wall configured to accommodate the electronic device and a coupling structure.

[0112] According to another embodiment, the ferrimagnetic core is embedded in the rear wall.

[0113] According to another embodiment, the wireless power signal is configured to travel from the wireless power transmission device through the rear wall to the second coil of the electronic device when the accessory and the electronic device are inductively coupled to the wireless power transmission device.

[0114] According to one embodiment, an electronic device capable of operating within a removable accessory is provided, the removable accessory having a wireless power receiving coil and a ferrimagnetic core, the electronic device comprising: a first coil configured to receive a wireless power signal from the wireless power transmitting device when the electronic device and the removable accessory are inductively coupled to the wireless power transmitting device and the ferrimagnetic core is in a first state; and a second coil configured to transmit additional wireless power signals to the wireless power receiving coil when the electronic device and the removable accessory are not inductively coupled to the wireless power transmitting device and the ferrimagnetic core is in a second state different from the first state.

[0115] According to another embodiment, the second coil has a central opening in which the first coil is formed, the first coil is configured to operate at a first maximum power level, and the second coil is configured to operate at a second maximum power level less than the first maximum power level.

[0116] The foregoing description is merely illustrative and various modifications can be made to the described implementation scheme. The described implementation scheme can be implemented independently or in any combination.

Claims

1. An electronic device, comprising: A first planar wireless charging coil, the first planar wireless charging coil having a winding wound around a central region; A second planar wireless charging coil, the second planar wireless charging coil having a winding positioned in the central region; A first ferrimagnetic core, which overlaps with the first planar wireless charging coil; as well as A second ferrimagnetic core, overlapping the second planar wireless charging coil, is positioned to direct received magnetic flux into the second planar wireless charging coil. The second ferrimagnetic core has a different magnetic reluctance than the first ferrimagnetic core. When the electronic device is coupled to a removable accessory in the absence of a wireless power transmission device, the first planar wireless charging coil is configured to transmit a first wireless power signal. When the electronic device is coupled to the wireless power transmission device in the absence of the removable accessory, the second planar wireless charging coil is configured to receive a second wireless power signal.

2. The electronic device of claim 1, wherein the first planar wireless charging coil is configured to operate at a first maximum power level, and wherein the second planar wireless charging coil is configured to operate at a second maximum power level greater than the first maximum power level.

3. The electronic device according to claim 1, wherein the first planar wireless charging coil is configured to stop transmitting the first wireless power signal when the second planar wireless charging coil receives the second wireless power signal.

4. The electronic device of claim 1, wherein the second planar wireless charging coil is configured to receive the second wireless power signal when the electronic device is coupled to the removable accessory and the wireless power transmission device.

5. The electronic device according to claim 1, wherein the first planar wireless charging coil and the second planar wireless charging coil are coplanar.

6. The electronic device according to claim 1, wherein the first ferrimagnetic core and the second ferrimagnetic core are coplanar.

7. The electronic device according to claim 1, wherein the first ferrimagnetic core and the second ferrimagnetic core are formed of different materials.

8. The electronic device according to claim 1, wherein the first ferrimagnetic core and the second ferrimagnetic core have different thicknesses.

9. The electronic device according to claim 1, further comprising: A ring-shaped permanent magnet having a central opening, wherein a first planar wireless charging coil and a second planar wireless charging coil are positioned within the central opening of the ring-shaped permanent magnet.

10. An accessory for an electronic device, wherein the electronic device has a first coil configured to transmit a first wireless power signal and a second coil configured to receive a second wireless power signal from a wireless power transmission device, the accessory comprising: A coil configured to receive the first wireless power signal from a first coil in the electronic device when the accessory is coupled to the electronic device; and A ferrimagnetic core, which overlaps with the coil, wherein the ferrimagnetic core operates in the following states: When the accessory and the electronic device are inductively coupled to the wireless power transmission device, the ferrimagnetic core operates in a first state, wherein the ferrimagnetic core has a first magnetic resistance in the first state; as well as When the accessory and the electronic device are not inductively coupled to the wireless power transmission device, the ferrimagnetic core operates in a second state, wherein the ferrimagnetic core has a second magnetic reluctance that is less than the first magnetic reluctance in the second state.

11. The appendix according to claim 10, wherein, In the first state, the subferromagnetic core is saturated by the magnetic field from the permanent magnet in the wireless power transmission device.

12. The appendix according to claim 11, wherein, In the second state, the ferrimagnetic core directs the received magnetic flux to the coil.

13. The accessory of claim 10, wherein the accessory further comprises a rear wall and coupling structure configured to receive the electronic device.

14. The appendix according to claim 13, wherein the ferrimagnetic core is embedded in the rear wall.

15. The accessory of claim 13, wherein the wireless power signal is configured to pass from the wireless power transmission device through the rear wall to the second coil of the electronic device when the accessory and the electronic device are inductively coupled to the wireless power transmission device.

16. An electronic device capable of operating within a removable accessory, wherein the removable accessory has a wireless power receiving coil and a ferrimagnetic core, the electronic device comprising: A first coil is configured to receive a wireless power signal from the wireless power transmission device when the electronic device and the removable accessory are inductively coupled to the wireless power transmission device and the ferrimagnetic core has a first magnetic resistance. as well as A second coil is configured to transmit an additional wireless power signal to the wireless power receiving coil when the electronic device and removable accessory are not inductively coupled to the wireless power transmission device and the ferrimagnetic core has a second magnetic resistance less than the first magnetic resistance.

17. The electronic device of claim 16, wherein the second coil has a central opening, wherein the first coil is formed in the central opening, wherein the first coil is configured to operate at a first maximum power level, and wherein the second coil is configured to operate at a second maximum power level less than the first maximum power level.

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