Wireless Frequency Identification for Multi-Device Wireless Chargers

Abstract

Systems, methods, and apparatus for wireless charging are disclosed. The charging device has a plurality of transmit coils, a driver circuit configured to provide a charging current to the resonant circuit, and a controller. A charging cell may provide a charging surface. The driver circuit may be configured to provide the charging current to the transmit coil. The charging device includes a wireless interface configured to transmit and receive radio frequency identification (RFID) signals. The controller may be configured to transmit an interrogation signal configured to stimulate the RFID tag via the wireless interface when the rechargeable device is initially placed on or near the surface of the wireless charger, refrain from initiating wireless charging of the rechargeable device if a response to the interrogation signal is received, and negotiate a charging configuration if no response to the interrogation signal is received.

Description

[Technical Field]

[0001] Priority claim This application claims priority to and the benefit of Nonprovisional Patent Application No. 17 / 400,043, filed with the United States Patent and Trademark Office on August 11, 2021, and Provisional Patent Application No. 63 / 065,465, filed with the United States Patent and Trademark Office on August 13, 2020, the entire contents of which applications are incorporated herein by reference in their entirety and for all applicable purposes as if fully set forth below.

[0002] The present invention relates generally to wireless charging of batteries, including batteries of mobile computing devices, and more particularly to demodulating signals received from a device being charged. [Background technology]

[0003] Wireless charging systems have been developed to allow certain types of devices to charge their internal batteries without using a physical charging connection. Devices that can utilize wireless charging include mobile and / or communications devices. Standards such as the Qi standard from the Wireless Power Consortium allow a device manufactured by one supplier to be wirelessly charged by a charger manufactured by a second supplier. Wireless charging standards are optimized for relatively simple devices and tend to provide basic charging functionality.

[0004] Improvements in wireless charging capabilities are necessary to accommodate the ever-increasing complexity of mobile devices and changing form factors, including the need for technologies to avoid collateral damage to devices unrelated to the wireless charging transaction. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 illustrates an example of a charging cell that may be employed to provide a charging surface in accordance with certain embodiments disclosed herein. [Figure 2] FIG. 2 is a diagram illustrating the layout of power transfer areas provided by a charging surface employing multiple layers of charging cells configured in accordance with certain embodiments disclosed herein. [Figure 3] FIG. 3 is a diagram illustrating a wireless power transmitter that may be provided in a charger base station according to certain aspects disclosed herein. [Figure 4] FIG. 4 is a diagram showing an RFID (Radio Frequency Identification) system. [Figure 5] FIG. 5 illustrates a first example of a charging device that may be adapted in accordance with certain aspects of the present disclosure. [Figure 6] FIG. 6 illustrates a second example of a charging device that may be adapted in accordance with certain aspects of the present disclosure. [Figure 7] FIG. 7 illustrates a third example embodiment of a charging device that may be adapted in accordance with certain aspects of the present disclosure. [Figure 8] FIG. 8 is a flowchart illustrating a first example method for monitoring a charging surface of a wireless charging device in accordance with certain aspects of the present disclosure. [Figure 9] FIG. 9 illustrates a fourth example of a charging device that may be adapted in accordance with certain aspects of the present disclosure. [Figure 10] FIG. 10 is a flow chart illustrating a second example method for monitoring a charging surface of a wireless charging device in accordance with certain aspects of the present disclosure. [Figure 11] FIG. 11 illustrates an example of a mobile device that can be adapted in accordance with certain aspects disclosed herein. [Figure 12] FIG. 12 is a flowchart illustrating a third example method for monitoring a charging surface of a wireless charging device in accordance with certain aspects of the present disclosure. [Figure 13] FIG. 13 illustrates an example of an apparatus employing processing circuitry that can be adapted in accordance with certain aspects disclosed herein. [Figure 14]FIG. 14 is a flowchart illustrating a fourth example method for monitoring a charging surface of a wireless charging device in accordance with certain aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0006] The detailed description set forth below in connection with the accompanying drawings is intended to illustrate various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that the concepts may be practiced without the specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0007] Certain aspects of wireless charging systems will now be presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the particular application and design constraints imposed on the overall system.

[0008] For example, an element, any portion of an element, or any combination of elements may be implemented in a “processing system” including one or more processors. Examples of processors include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic, discrete hardware circuits, and other suitable hardware configured to perform various functions described throughout this disclosure. One or more processors of a processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or the like. Software may reside in a processor-readable storage medium. Processor-readable storage media, also referred to herein as computer-readable media, may include, for example, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs)), smart cards, flash memory devices (e.g., cards, sticks, key drives), near-field communication (NFC) tokens, random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, removable disks, carrier waves, transmission lines, or any other medium suitable for storing or transmitting software. The computer-readable medium may be resident within the processing system, external to the processing system, or distributed across multiple entities, including the processing system. The computer-readable medium may also be embodied in a computer program product.As an example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

[0009] overview Certain aspects of the present disclosure relate to systems, devices, and methods applicable to wireless charging devices. A charging cell is comprised of one or more inductive coils to provide a charging surface for the charging device, enabling the charging device to wirelessly charge one or more rechargeable devices. The location of the device being charged can be detected via sensing techniques that relate the device's location to changes in physical properties about a known location on the charging surface. Position sensing can be implemented using capacitive, resistive, inductive, contact, pressure, load, strain, and / or another suitable type of sensing.

[0010] In one aspect of the disclosure, an apparatus includes a power source for charging a battery, a plurality of charging cells arranged in a matrix, a first plurality of switches, each configured to couple a row of coils in the matrix to a first terminal of the battery charging power source, and a second plurality of switches, each configured to couple a column of coils in the matrix to a second terminal of the battery charging power source. Each charging cell of the plurality of charging cells may include one or more coils surrounding a power transfer area. The plurality of charging cells may be positioned adjacent to a charging surface of the charging device, with the power transfer areas of the charging cells of the plurality of charging cells not overlapping. A device placed on the surface can receive power wirelessly transferred via one or more charging cells.

[0011] In some cases, the device may be referred to as a charging surface. Power can be wirelessly transmitted to powered devices placed anywhere on the device's surface. The powered devices can have any defined size and / or shape and can be placed in any individual configuration that allows charging. Multiple powered devices can be charged simultaneously on a single charging surface. The device can track the movement of one or more powered devices across the charging surface.

[0012] Certain aspects disclosed herein relate to the detection of RFID tags, contactless credit cards, and other items that have circuitry responsive to near-field communication (NFC) signals and that may be attached to or coupled to a rechargeable device placed on or near a charging surface of a charging device. The charging device may have multiple transmit coils, a driver circuit configured to provide a charging current to a resonant circuit, and a controller. A charging cell may provide the charging surface. The driver circuit may be configured to provide the charging current to the transmit coil. The charging device includes a wireless interface configured to transmit and receive RFID signals or other NFC signals. In one example, the controller may be configured to transmit an interrogation signal configured to stimulate the RFID tag via the wireless interface when the rechargeable device is initially placed on or near the surface of the wireless charger, refrain from initiating wireless charging of the rechargeable device if a response to the interrogation signal is received, and negotiate a charging configuration if no response to the interrogation signal is received. The charging configuration negotiation precedes charging. In one example, the charging device transmits a wireless ping to confirm the presence of the rechargeable device and determine a charging configuration that defines the transmit coil and charging current level to be used for charging.

[0013] In some implementations, the wireless charger may transmit an interrogation signal and not send a Ping if the response to the interrogation signal indicates the presence of an RFID tag or other RFID-enabled item associated with the rechargeable device. In some implementations, the rechargeable device may transmit an interrogation signal and not respond to a Ping if the response to the interrogation signal indicates the presence of an RFID tag or RFID-enabled item associated with the rechargeable device. The rechargeable device may alternatively respond to the Ping by sending a message to the wireless charger denying charging if an RFID tag or RFID-enabled item is present.

[0014] Charging cell According to certain aspects disclosed herein, a charging surface is provided using charging cells within a charging device, and the charging cells are arranged adjacent to the charging surface. In one example, the charging cells are arranged in one or more layers on the charging surface according to a honeycomb packaging configuration. The charging cells can be implemented using one or more coils, each capable of inducing a magnetic field along an axis substantially perpendicular to the charging surface adjacent the coil. As used herein, a charge cell refers to a component having one or more coils configured to generate an electromagnetic field that is additive to the fields generated by other coils in the charge cell and oriented along or adjacent a common axis. In some examples, the coils in the charge cells are formed using traces on a printed circuit board. In some examples, the coils of the charge cells are formed by helically winding wire to obtain a planar coil or a coil with a generally cylindrical outer shape. As an example, Litz wire can be used to form a planar or substantially flat winding, providing a coil with a central power transfer region.

[0015] In some implementations, the charge cells include coils stacked along a common axis and / or overlapping to contribute to an induction field substantially orthogonal to the charging surface. In some implementations, the charge cells include coils positioned within a defined portion of the charging surface and contributing to an induction field within a substantially orthogonal portion of the charging surface associated with the charge cell. In some implementations, the charge cells may be configurable by providing activation currents to coils included in dynamically defined charge cells. For example, a charging device may include multiple coil stacks deployed across a charging surface, and the charging device may detect the location of a device to be charged and select some combination of the coil stacks to provide a charge cell adjacent to the device to be charged. In some examples, a charge cell may include or be characterized as a single coil. However, it should be understood that a charge cell may include multiple stacked coils and / or multiple adjacent coils or stacks of coils. Coils may be referred to herein as charging coils, wireless charging coils, transmitter coils, transmission coils, power sending coils, power transmitter coils, etc.

[0016] FIG. 1 illustrates an example of a charging cell 100 that may be deployed and / or configured to provide a charging surface for a charging device. As described herein, the charging surface may include an array of charging cells 100 disposed on one or more substrates 106. Circuitry comprised of one or more integrated circuits (ICs) and / or discrete electronic components may be disposed on the one or more substrates 106. The circuitry may include drivers and switches used to control current supplied to a coil used to transfer power to a powered device. The circuitry may be configured as a processing circuit including one or more processors and / or one or more controllers that may be configured to perform certain functions disclosed herein. In some embodiments, some or all of the processing circuitry may be external to the charging device. In some embodiments, a power source may be coupled to the charging device.

[0017] The charge cell 100 can be provided near an exterior surface area of ​​a charging device, onto which one or more devices can be placed for charging. The charging device can include multiple instances of the charge cell 100. In one example, the charge cell 100 has a substantially hexagonal shape surrounding one or more coils 102, which can be constructed using conductors, wires, or circuit board traces capable of receiving sufficient current to generate an electromagnetic field in a power transfer area 104. In various embodiments, some coils 102 may have a substantially polygonal shape, including the hexagonal charge cell 100 illustrated in FIG. 1 . In other embodiments, coils 102 having other shapes are provided. The shape of the coils 102 can be determined, at least in part, by the capabilities or limitations of manufacturing technology and / or to optimize the layout of the charge cell on a substrate 106, such as a printed circuit board. Each coil 102 can be implemented using spirally configured wires, printed circuit board traces, and / or other connectors. Each charge cell 100 can span two or more layers separated by insulators or the substrate 106, such that the coils 102 on different layers are centered about a common axis 108.

[0018] FIG. 2 illustrates the arrangement of power transfer areas across a surface 200 of a charging device employing multiple layers of charge cells configured according to certain embodiments disclosed herein. The charging device may be configured with four layers of charge cells 202, 204, 206, and 208. In FIG. 2, each power transfer area provided by the first layer of charge cells 202 is labeled "L1," each power transfer area provided by the second layer of charge cells 204 is labeled "L2," each power transfer area provided by the third layer of charge cells 206 is labeled "L3," and each power transfer area provided by the fourth layer of charge cells 208 is labeled "L4." The charge cells 202, 204, 206, and 208 may be served by polygonal power transfer areas of the transfer coil. In another implementation, the charge coil may comprise a helically wound planar coil constructed from wire, each wound to provide a substantially circular power transfer area. In the latter example, multiple spirally wound planar coils may be deployed in a stack beneath the charging surface of the wireless charging device.

[0019] 3 illustrates a wireless transmitter 300 that may be provided in a charger base station. A controller 302 may receive a feedback signal that is filtered or otherwise processed by a conditioning circuit 308. The controller may control the operation of a driver circuit 304 that provides an alternating current to a resonant circuit 306 that includes a capacitor 312 and an inductor 314. The resonant circuit 306 is also referred to herein as a tank circuit, an LC tank circuit, and / or an LC tank, and the voltage 316 measured at an LC node 310 of the resonant circuit 306 is also referred to as the tank voltage.

[0020] Wireless transmitter 300 can be used by a charging device to determine whether a compatible device has been placed on the surface of the charging device. For example, the charging device can identify when a compatible device has been placed on the surface of the charging device by transmitting an intermittent test signal (active ping or digital ping) via wireless transmitter 300, where resonant circuit 306 can detect or receive an encoded signal if the compatible device responds to the test signal or changes its characteristics. The charging device can be configured to excite one or more coils in at least one charging cell upon receiving a response signal defined by standard, convention, manufacturer, or application. In some examples, the compatible device can respond to the ping by communicating the received signal strength so that the charging device can find the optimal charging cell to use to charge the compatible device.

[0021] A passive ping technique can use the voltage and / or current measured or observed at LC node 310 to identify the presence of a receive coil in proximity to a charging pad of a device adapted according to certain aspects disclosed herein. Many conventional wireless charger transmitters include circuitry to measure the voltage at LC node 310 or measure the current in the network. These voltages and currents may be monitored for power regulation purposes and / or to support communication between devices. In the example shown in FIG. 3 , the voltage at LC node 310 is monitored, but it is contemplated that the current may additionally or alternatively be monitored to support a passive ping in which a short pulse is provided to resonant circuit 306. The response of resonant circuit 306 to a passive ping (initial voltage V 0 ) is measured by the voltage at LC node 310 (V LC ) can be expressed as follows: TIFF0007807093000001.tif12170

[0022] According to certain aspects disclosed herein, coils in one or more charging cells can be selectively activated to provide an optimal electromagnetic field for charging compatible devices. In some examples, coils are assigned to charging cells, and some charging cells may overlap with other charging cells. In the latter case, an optimal charging configuration can be selected on a per-charge-cell basis. In other examples, charging cells may be defined based on the placement of the device to be charged on the charging device surface. In such other examples, the combination of coils activated for each charging event may vary. In some implementations, the charging device may include driver circuitry capable of selecting one or more cells and / or one or more predetermined charging cells for excitation during a charging event.

[0023] RFID In certain embodiments of the present disclosure, the charging device may refrain from activating one or more wireless charging coils if an RFID tag is detected on or near the surface of the wireless charging device and / or if the RFID tag may be damaged if activated. RFID technology was originally used for identification systems, and RFID tags are traditionally used for inventory control purposes, at points of sale, and / or at exits of commercial establishments. RFID technology may be included in mobile devices, such as smartphones, to enable interaction with other mobile devices and other RFID systems. Some smartphones support the Near Field Communication (NFC) protocol, which includes a standard-defined communication protocol that allows two devices to communicate at distances of up to 4 cm, and is used in mobile payment systems, etc. Some NFC-enabled devices can read RFID tags or have similar functionality to RFID tags. While certain embodiments of the present disclosure are described using the example of an RFID system, the concepts are equally applicable to NFC systems and NFC-enabled items.

[0024] FIG. 4 illustrates specific embodiments of RFID system configurations 400, 420. In each embodiment, RFID readers 402, 422 include processing circuits 404, 424 and RFID radios 406, 426. The RFID radios 406, 426 can operate at one of several frequencies defined for use with specific types of RFID tags. In one example, the RFID radios 406, 426 may be configured to transmit or receive at 13.56 MHz when used in certain smart card applications. In another example, the RFID radios 406, 426 may be capable of operating in the 2.45 GHz to 5.80 GHz band defined for use in IEEE 802.11 wireless local area networks (WLANs) and Bluetooth standards. In another example, the RFID radios 406, 426 may operate at frequencies between 3.1 and 10 GHz for ultra-wideband applications. The RFID readers 402 , 422 include antennas 408 , 428 that may be configured according to the frequency bands used by the RFID radios 406 , 426 .

[0025] In the first configuration 400, the RFID system supports the use of passive RFID tags 412. Passive RFID tags 412 do not have their own power source but are instead powered by a small amount of energy extracted from an RF field generated by an interrogator, which may be included in the RFID reader 402. The interrogator transmits an RFID interrogation signal at a frequency that causes the RFID tag 412 to wake and provide a reply code. The RFID interrogation signal is transmitted at a sufficient power level so that the RFID tag 412 can extract enough energy to transmit the reply code. In one example, the RFID radio 416 detects and recognizes the RFID interrogation signal and generates power for its own use and the use of the transponder circuitry 414. In some embodiments, the RFID radio 416 provides a clock signal used by the transponder circuitry 414. The transponder circuitry 414 may include a state machine or other sequencing logic.

[0026] The passive RFID tag 412 includes an antenna 418 configured according to the frequency band used by the RFID radio 416. In one example, the RFID radio 416 and transponder circuit 414 are located on a single semiconductor integrated circuit (IC) or chip, or the antenna 418 can be fabricated within the IC, located within a metal or other conductive layer on the IC, painted onto the IC's casing, or located remotely from or in close proximity to the chip. Passive RFID tags 412 typically operate at low frequencies selected from the low-frequency 120-150 kHz range and / or up to 13.56 MHz, the RFID operating frequency of smart cards and other devices. Certain passive RFID tags 412 can be configured to detect and recognize RFID interrogation signals at the high-frequency end or ultra-high frequency (UHF) band, including 433 MHz.

[0027] In the second configuration 400, the RFID system supports the use of active or power-assisted RFID tags 432. The active or power-assisted RFID tags 432 receive an external power source, are capable of more complex communications, and / or can transmit at higher frequencies. The active or power-assisted RFID tags 432 typically include processing circuitry 434 capable of performing and managing specific functions. The active or power-assisted RFID tags 432 typically include memory capable of providing detailed information beyond the serial number stored by the passive RFID tag 412. In one example, the RFID radio 436 can detect and recognize RFID signals, cause the processing circuitry 434 to decode the received RFID signal, construct a response message, and generate a wake-up signal that causes the RFID radio 436 to transmit the response message. The processing circuitry 434 typically includes a processor, controller, and / or state machine, which may be configurable during operation. The active or power-assisted RFID tag 432 includes an antenna 438 configured according to the frequency band used by the RFID radio 436. In one example, the antenna 438 may be configured as a coil antenna.

[0028] The RFID tags 412, 432 are designed to operate at low transmit power. The antennas 418, 438 are typically designed to handle low-power RFID signals, and the RFID radios 416, 436 include transmit and receive circuitry that is expected to operate with low current and / or low voltage signals. The wireless charging coil may induce signals into the transmit and receive circuitry of the RFID radios 416, 436 and / or the antennas 418, 438 at power levels that could damage the RFID radios 416, 436 or antennas 418, 438.

[0029] Certain aspects of the present disclosure provide systems, methods, and techniques for detecting the presence of an RFID tag 412, 432 on or near the surface of a wireless charger before initiating charging of a device placed on the surface proximate the RFID tag 412, 432. As an example, the RFID tag 412, 432 can be embedded in a credit card that fits into the cover of a rechargeable device, such as a smartphone. The smartphone may be placed in its cover on the charging surface to charge, creating a risk of damage to the RFID tag 412, 432 from the electromagnetic charging flux emanating from the charging surface. Reliable detection of the RFID tag 412, 432 can prevent damage to the RFID tag 412, 432. In certain implementations, one or more RFID readers 402, 422 can be integrated into the wireless transmitter of a multi-device charging device. The RFID readers 402, 422 can be used to detect the presence of the RFID tag 412, 432 before initiating wireless power transfer through one or more zones or regions of the charging surface. In some implementations, detecting the presence of an RFID tag 412, 432 can exclude one or more wireless charging coils from the charging configuration and prevent charging current from being applied to the one or more wireless charging coils.

[0030] Referring to example 500 shown in FIG. 5 , a charging device adapted according to certain aspects of the present disclosure includes a wireless power transmitter 502 and an RFID reader 504. Wireless power transmitter 502 may correspond to wireless transmitter 300 of FIG. 3 , and RFID reader 504 may correspond to RFID reader 402 or 422 of FIG. 4. Wireless power transmitter 502 may include a driver circuit 512 configured to provide a charging current to one or more wireless charging coils 506. Driver circuit 512 may correspond to driver circuit 304 of FIG. 3 .

[0031] In certain implementations, one or more wireless charging coils 506 can function as an antenna for the RFID radio 514 in the RFID reader 504. The wireless charging coil 506 can function as an antenna for wireless power transfer and RFID signaling when the wireless power transfer operates at the same frequency or a harmonic frequency as the RFID radio frequency. In one example, the wireless charging coil 506 can also function as an antenna for wireless power transfer in a wireless charging system defined by the Alliance for Wireless Power (A4WP), which transfers power at a relatively high frequency of 6.78 MHz, half the 13.56 MHz upper frequency limit of certain passive RFID technologies.

[0032] Referring to the example shown in FIG. 6 , a charging apparatus adapted according to certain aspects of the present disclosure includes multiple RFID radios 612, 614, 616 configured to monitor different zones or regions 602, 604, 606 across a wireless charging apparatus surface 600. A multi-device wireless charging apparatus provided with multiple RFID radios 612, 614, 616 can be configured such that each rechargeable device placed on the wireless charging apparatus surface 600 is monitored and / or interrogated by a dedicated RFID radio 612, 614, 616. The size, shape, and location of the zones 602, 604, 606 may be fixed or predetermined by design and can be configured based on the detected location and orientation of the rechargeable device. A multi-device wireless charging apparatus provided with multiple RFID radios can be configured such that each rechargeable device placed on the wireless charging apparatus surface 600 is aligned or monitored by a dedicated RFID radio 612, 614, 616.

[0033] In another example, a charging device adapted according to certain aspects of the present disclosure uses one or more wireless charging coils 608, 610 to function as antennas for RFID tag detection purposes. Some wireless charging coils 608 coupled to RFID radios 612, 614, 616 associated with zones 602, 604, 606 may be located entirely within the zones 602, 604, 606 monitored by the RFID radios 612, 614, 616, while other wireless charging coils 610 coupled to the RFID radios 612, 614, 616 may be located partially within the zones 602, 604, 606 monitored by the RFID radios 612, 614, 616. In the latter example, a particular wireless charging coil 610 may be coupled to different RFID radios 612, 614, 616 at different times such that adjacent RFID radios 612, 614, 616 may operate at mutually exclusive times to detect the presence of an RFID tag within a corresponding zone 602, 604, 606 on the surface 600 of the wireless charging device.

[0034] In another example, a charging device adapted according to certain aspects of the present disclosure couples selected wireless charging coils 608, 610, 618, and / or 620 to RFID radios 612, 614, 616 for use as antennas for RFID tag detection purposes for the detected rechargeable device. For example, the wireless charging device may determine that a rechargeable device is to be charged using wireless charging coils 610, 618, 620 and couple those wireless charging coils 610, 618, 620 to the RFID radios 612, 614, 616 assigned to the detected rechargeable device, regardless of the zones 602, 604, 606 in which the wireless charging coils 610, 618, 620 are located.

[0035] Referring to the example shown in FIG. 7 , a charging device adapted according to certain aspects of the present disclosure includes multiple RFID radios 712, 714, 716, each coupled to a dedicated RFID antenna 702, 704, 706. RFID antennas 702, 704, 706 define a monitoring zone corresponding to wireless charging device surface 700. RFID antennas 702, 704, 706 may correspond to the boundaries of the monitoring zone. RFID antennas 702, 704, 706 may be distributed across wireless charging device surface 700 and may define the location, size, and orientation of the monitoring zone. In the illustrated example, the monitoring zones divide wireless charging device surface 700 into three equal regions with a common size and orientation. In other examples, the monitoring zones may have different shapes and / or sizes. In some examples, the monitoring zones may overlap.

[0036] In the illustrated example, each RFID antenna 702, 704, 706 is formed as a loop that substantially defines the area of ​​the corresponding monitoring zone. In some examples, the RFID antennas 702, 704, 706 precisely define the boundaries of the monitoring zone. In some examples, the RFID antennas can send and receive signals to and from RFID tags placed some distance outside the area defined by the RFID antennas 702, 704, 706, and these RFID antennas 702, 704, 706 approximate the boundaries of the monitoring zone.

[0037] Each of the RFID antennas 702, 704, 706 is coupled to a corresponding dedicated RFID radio 712, 714, 716 and is configured to detect the presence of an RFID tag within a corresponding monitoring zone on the wireless charging device surface 700. Each of the RFID antennas 702, 704, 706 can include a coil that circles the monitoring zone multiple times, thereby providing a multi-turn coil antenna. In this example, the charging device provides an antenna for RFID detection that is separate from the wireless charging coil used to transfer power to the rechargeable device.

[0038] FIG. 8 is a flowchart 800 illustrating a method for monitoring at least a portion of a charging surface of a wireless charging device according to certain aspects of the present disclosure. The method may be executed by a controller within the wireless charging device after an object is detected on the surface of the wireless charging device. The method may be executed periodically and / or after object detection at block 802. In some examples, an object may be identified as a chargeable object by a passive ping. In some examples, an object may be identified as a chargeable object by a capacitance sensing procedure in which a change in capacitance measured at one or more wireless charging coils indicates the placement or removal of the object. In some examples, the presence of an object may be identified using one or more sensors that detect changes in stress or strain on the surface of the wireless charging device. In other examples, the presence of an object may be identified using one or more optical sensors that detect interruptions in an optical path. In other examples, the presence of an object may be identified using one or more sensors that detect changes in an electromagnetic field.

[0039] In block 804, the controller may transmit an interrogation signal via an antenna on the surface of the wireless charging device. The interrogation signal may be configured to wake one or more RFID tags, which may be located on or near the surface of the wireless charging device. The interrogation signal may have sufficient energy to power passive RFID tags, which may be located on or near the surface of the wireless charging device. RFID tags that receive the interrogation signal are expected to transmit a response, and in block 806, the controller may determine whether a response signal indicating the presence of at least one RFID tag located on or near the surface of the wireless charging device is received. If a response signal is received from an RFID tag, in block 808, the controller may inhibit charging via one or more wireless charging coils configured to provide a charging flux through the surface area covered by the antenna that transmitted the interrogation signal.

[0040] If a response signal is not received from the RFID tag, the controller may transmit a digital ping or other higher power discovery signal to the detected object via one or more wireless charging coils in block 810. The digital ping or other higher power detection may be configured to enable the controller to determine whether the detected object is a chargeable object and to provide a charging setting that defines the transmit power level and one or more wireless charging coils to be used to charge the responding chargeable object.

[0041] In block 812, the controller may determine whether the chargeable object responded to a digital ping or other higher power discovery signal. If no response is received in block 812, the controller may treat the detected object as a foreign object and terminate the procedure in block 814. If a response is received in block 812, then in block 816, the controller may configure appropriate charging settings and begin charging the responding chargeable object.

[0042] 9 , a charging device adapted according to certain aspects of the present disclosure includes a single RFID radio 904 coupled to a single RFID antenna 902 that substantially defines a monitoring zone on a multi-device wireless charging device surface 900. RFID radio 904 can be configured to track placement of rechargeable devices on wireless charging device surface 900 and initiate an interrogation procedure to determine whether a newly placed rechargeable device is associated with an RFID tag.

[0043] In the illustrated example, the RFID antenna 902 is formed as a loop surrounding a wireless charging coil that provides charging flux through the wireless charging device surface 900. The RFID antenna 902 can include a coil that circles the multi-device wireless charging device surface 900 multiple times, thereby providing a multi-turn coil antenna. In some examples, the RFID antenna 902 precisely defines the boundary of the monitoring zone. In some examples, the RFID antenna 902 can transmit and receive signals to and from an RFID tag placed some distance outside the area defined by the RFID antenna 902, with the RFID antenna 902 approximating the boundary of the monitoring zone. The RFID antenna 902 is coupled to a dedicated RFID radio 904 and configured to detect the presence of an RFID tag within the monitoring zone on the wireless charging device surface 900. In this example, the charging device provides an antenna for RFID detection that is separate from the wireless charging coil used to transfer power to the rechargeable device. In other examples, the RFID radio 904 can be coupled to multiple wireless charging coils 906, which can function as antennas that provide RFID coverage to the wireless charging device surface 900. In one example, all of the wireless charging coil 906 is used to form an RFID antenna. In another example, the RFID antenna is formed using the wireless charging coil 906 located around the periphery of the surface 900 of the wireless charging device.

[0044] The use of a single RFID radio 904 coupled to a single RFID antenna 902 that substantially defines a monitoring zone on the wireless charging device surface 900 may operate in a multi-device mode by tracking the placement of objects on the surface 900 and the subsequent movement or removal of those objects from the surface 900. Because there is a finite time difference between object placements, it is expected that the wireless charging device controller will be able to detect each placement, movement, and / or removal event. It is highly unlikely that two objects will be placed, moved, or removed at the exact same time. The controller may be configured to maintain information regarding the state of the wireless charging device surface 900 and the specific characteristics of objects placed on the surface 900.

[0045] In certain implementations, the controller may be configured to determine whether an object placed on the surface 900 has an RFID tag attached to or associated with it, and then associate the RFID tag with the object. For example, suppose a first device is placed on the surface 900 when no objects are present on or near the surface 900. The first device may be attached to a first RFID tag, and the controller may prohibit charging of the first device. Subsequently, when a second device is placed on the surface 900, the controller may interrogate RFID tags on or near the surface 900. This interrogation may be expected to distinguish the first RFID tag from other RFID tags. The controller may associate the first RFID tag with the first object and remove the first RFID tag from consideration when determining whether to charge the second object. The controller may initiate charging of the second object provided that a second RFID tag is not detected.

[0046] 10 is a flowchart 1000 illustrating a method for monitoring at least a portion of a charging surface of a wireless charging device using a single RFID radio, according to certain aspects of the disclosure. This method may be employed when the RFID radio is used to monitor an area of ​​the charging surface where multiple rechargeable devices may be placed. In some implementations, the RFID radio is used to monitor the entire charging surface.

[0047] The method may be performed by a controller within a wireless charging device after one or more objects are detected on the surface of the wireless charging device. The method may be performed in a context 1002 in which a first object is detected and associated with a first RFID tag and charging is inhibited near the first object. The method may be performed periodically and / or after a second object is detected in block 1004. The second object may be identified as a chargeable object by a passive ping. The second object may be identified as a chargeable object by a capacitance sensing procedure in which a change in capacitance measured at one or more wireless charging coils indicates the placement or removal of the second object. In one example, the presence of an object may be identified using one or more sensors that detect changes in stress or strain on the surface of the wireless charging device. In another example, the presence of an object may be identified using one or more optical sensors that detect an interruption in an optical path. In another example, the presence of an object may be identified using one or more sensors that detect changes in an electromagnetic field.

[0048] In block 1006, the controller may transmit an interrogation signal via an antenna on the surface of the wireless charging device. The interrogation signal may be configured to wake one or more RFID tags that may be on or near the surface of the wireless charging device. The interrogation signal may have sufficient energy to power one or more passive RFID tags that may be located on or near the surface of the wireless charging device. RFID tags that receive the interrogation signal are expected to transmit a response, and in block 1008, the controller may determine whether a response signal indicating the presence of at least one RFID tag located on or near the surface of the wireless charging device is received. If a response signal is received from an RFID tag, then in block 1010, the controller may determine whether a new RFID tag has been detected. The controller may ignore a response to the first RFID tag if the controller previously detected the presence of the first RFID tag. The controller may operate the wireless charging device in a mode consistent with the first RFID tag being present on or in proximity to the first object. That is, the controller may prohibit charging via one or more wireless charging coils near the first object. If the controller determines that the second RFID tag has responded to the query initiated in block 1006, the controller may proceed to block 1012 and inhibit charging via one or more wireless charging coils configured to provide a charging flux in the vicinity of the second object.

[0049] If a second RFID tag is not detected, the controller may transmit a digital ping or other higher power discovery signal to the second object via one or more wireless charging coils in block 1014. The digital ping or other higher power detection is configured to enable the controller to determine whether the second object is a chargeable object and to provide a charging setting that defines the transmit power level and one or more wireless charging coils to be used to charge the responding chargeable object.

[0050] In block 1016, the controller may determine whether the chargeable object responded to a digital ping or other higher power discovery signal. If no response is received in block 1016, the controller may treat the detected object as a foreign object and end the procedure in block 1018. If a response is received in block 1016, then in block 1020, the controller may configure appropriate charging settings and begin charging the responding chargeable object.

[0051] 11 shows an example of a mobile device 1100 that may be configured to detect the presence of an RFID tag 1104 before the mobile device 1100 is placed on or near a surface of a wireless charger 1106 and receives electromagnetic flux 1110 from the wireless charger 1106. The mobile device 1100 includes a controller 1112 or other processor and has processing circuitry 1102 that further includes or is coupled to a wireless power receiver 1114 and an RFID radio 1116. The mobile device 1100 may be a mobile phone, a smartphone, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, an entertainment device, a wearable computing device (e.g., a smart watch, a health or fitness tracker, eyewear, etc.), a consumer electronics device, a sensor, a security device, a drone, a multicopter, or any other similarly functional device.

[0052] The wireless power receiver 1114 includes or is coupled to a receive coil 1118 configured to generate a charging current in response to electromagnetic flux 1110 received from the wireless charger 1106. The receive coil 1118 functions as an antenna tuned to the frequency of the electromagnetic flux 1110. The RFID radio 1116 may be configured to transmit and receive signals 1122, 1124 via an RFID antenna 1120 at frequencies defined by RFID standards and protocols. The receive coil 1118 performs the function of the RFID antenna 1120. The RFID tag 1104 includes the antenna 1108 and can operate as a passive or active RFID tag.

[0053] In certain implementations, the controller 1112 can be configured to detect the presence of the RFID tag 1104 and can inhibit wireless charging if the RFID tag 1104 is determined to be present. The processing circuit 1102 can be configured to notify a user of the mobile device 1100 that the RFID tag 1104 is present and that the RFID tag 1104 should be removed from any position between the receive coil 1118 and the surface of the wireless charger 1106 so that charging can begin.

[0054] 12 is a flowchart 1200 illustrating the operation of a mobile device 1100 configured to prevent charging if the presence of an RFID tag 1104 is detected. The method may be performed by a controller 1112 within the mobile device 1100. In block 1202, the controller 1112 may detect a digital ping. The digital ping may be transmitted by the wireless charger 1106 and may be configured to identify the mobile device 1100, determine the capabilities of the mobile device 1100, verify the state of the mobile device, and / or determine charging settings.

[0055] According to certain aspects of the present disclosure, at block 1204, the controller 1112 may transmit an RFID interrogation signal 1122 to its RFID radio 1116. The RFID interrogation may wake and / or power any RFID tags 1104 located near the mobile device 1100. An RFID tag 1104 that detects the RFID interrogation signal 1122 responds by transmitting a response signal 1124 that carries the RFID tag's 1104 identifier and / or message. If at block 1206, the controller 1112 does not detect the response signal 1124, the method proceeds to block 1208, where the controller 1112 may respond with a digital ping and engage in charging of the mobile device 1100.

[0056] At block 1206, if the controller 1112 detects a response signal 1124 after the RFID interrogation signal, the method proceeds to block 1210. At block 1210, the controller 1112 may deny charging of the mobile device 1100. In one example, the controller 1112 may deny charging of the mobile device 1100 by refraining from responding to a digital ping. In another example, the controller 1112 may deny charging of the mobile device 1100 by sending an “End Power Transfer” (EPT) message to the wireless charger 1106. At block 1212, the controller 1112 may display an error message on the mobile device 1100 indicating the presence of the RFID tag 1104. The message may suggest moving the RFID tag 1104 out of range of the wireless charger 1106.

[0057] In certain implementations, the RFID radio 1116 can be used for near-field communication with the wireless charger 1106. In these implementations, the wireless charger 1106 can include its own RFID radio, such as one or more of the RFID radios 612, 614, 616, 712, 714, 716, and 904 illustrated in FIGS. 6, 7, and 9. The wireless charger 1106 can use its RFID radio to participate in near-field communication with the mobile device 1100. The near-field communication occurs according to a standard-defined protocol and can involve a large amount of data exchange while the mobile device 1100 is being charged by the wireless charger 1106. In one example, the near-field communication can be used to transfer firmware updates from the mobile device 1100 to the wireless charger 1106. In another example, the near-field communication can be used to transfer status statistics and / or charging data from the wireless charger to the powered device.

[0058] Processing circuit example FIG. 13 illustrates an example of a hardware implementation of an apparatus 1300 that can be incorporated into a charging apparatus or a powered device that enables wireless charging of a battery. In some examples, the apparatus 1300 can perform one or more functions disclosed herein. According to various aspects of the present disclosure, the elements, any portion of the elements, or any combination of the elements disclosed herein can be implemented using a processing circuit 1302. The processing circuit 1302 can include one or more processors 1304 controlled by a combination of hardware and software modules. Examples of the processor 1304 include a microprocessor, a microcontroller, a digital signal processor (DSP), an SoC, an ASIC, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a sequencer, gate logic, discrete hardware circuits, and other suitable hardware configured to perform various functions described throughout this disclosure. The one or more processors 1304 can include dedicated processors that perform specific functions and can be configured, augmented, or controlled by one of the software modules 1316. The one or more processors 1304 may be configured through a combination of software modules 1316 loaded during initialization, and may be further configured by loading or unloading one or more software modules 1316 during operation.

[0059] In the depicted example, the processing circuit 1302 may be implemented with a bus architecture, indicated generally by bus 1310. The bus 1310 may include any number of interconnected buses and bridges, depending on the particular application and overall design constraints of the processing circuit 1302. The bus 1310 links various circuits, including one or more processors 1304 and storage 1306. The storage 1306 may include memory devices and mass storage devices, and is also referred to herein as a computer-readable medium and / or a processor-readable medium. The storage 1306 may include a transient storage medium and / or a non-transitory storage medium.

[0060] The bus 1310 may link various other circuits, such as timing sources, timers, peripherals, voltage regulators, and power management circuits. A bus interface 1308 may provide an interface between the bus 1310 and one or more transceivers 1312. In one example, the transceiver 1312 may be provided to allow the device 1300 to communicate with a charging device or a powered device according to a standard defined protocol. Depending on the nature of the device 1300, a user interface 1318 (e.g., keypad, display, speaker, microphone, joystick) may also be provided and may be communicatively coupled to the bus 1310 directly or via the bus interface 1308.

[0061] The processor 1304 may be responsible for managing the bus 1310 and for overall processing, including the execution of software stored on computer-readable media, including storage 1306. In this regard, the processing circuitry 1302, including the processor 1304, may be used to implement any of the methods, functions, and techniques disclosed herein. The storage 1306 may be used to store data that is manipulated by the processor 1304 when executing software, which may be configured to perform any one of the methods disclosed herein.

[0062] The one or more processors 1304 of the processing circuitry 1302 can execute software. Software shall be interpreted broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, algorithms, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside in storage 1306 in computer-readable form or on an external computer-readable medium. The external computer-readable medium and / or storage 1306 may include non-transitory computer-readable media. Non-transitory computer-readable media may include, for example, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs)), smart cards, flash memory devices (e.g., “flash drives,” cards, sticks, key drives), RAM, ROM, programmable read-only memory (PROM), erasable PROM (EPROM) including EEPROM, registers, removable disks, and any other suitable medium for storing software and / or instructions that can be accessed and read by a computer. Computer-readable media and / or storage 1306 may also include, for example, carrier waves, transmission lines, and any other suitable medium for transmitting software and / or instructions that can be accessed and read by a computer. Computer-readable media and / or storage 1306 may be resident in processing circuit 1302, in processor 1304, external to processing circuit 1302, or distributed across multiple entities including processing circuit 1302. The computer readable medium and / or storage 1306 may be embodied in a computer program product.As an example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

[0063] Storage 1306 may maintain and / or organize software such as loadable code segments, modules, applications, programs, etc., also referred to herein as software modules 1316. Each of the software modules 1316 may include instructions and data that, when installed or loaded into the processing circuitry 1302 and executed by one or more processors 1304, contribute to a runtime image 1314 that controls the operation of the one or more processors 1304. Particular instructions, when executed, may cause the processing circuitry 1302 to perform functions in accordance with particular methods, algorithms, and processes described herein.

[0064] Some of the software modules 1316 may be loaded during initialization of the processing circuit 1302, and these software modules 1316 may configure the processing circuit 1302 to enable it to perform various functions disclosed herein. For example, some software modules 1316 may configure the internal devices and / or logic circuits 1322 of the processor 1304 and may manage access to external devices such as the transceiver 1312, the bus interface 1308, the user interface 1318, timers, and math coprocessors. The software modules 1316 may include a control program and / or operating system that interacts with interrupt handlers and device drivers and controls access to various resources provided by the processing circuit 1302. Resources may include memory, processing time, access to the transceiver 1312, the user interface 1318, and the like.

[0065] The one or more processors 1304 of the processing circuit 1302 are multifunctional, whereby some of the software modules 1316 can be loaded and configured to perform different functions or different instances of the same function. Additionally, the one or more processors 1304 may be adapted to manage background tasks initiated in response to inputs, for example, from the user interface 1318, the transceiver 1312, and device drivers. To support the execution of multiple functions, the one or more processors 1304 may be configured to provide a multitasking environment, whereby each of the multiple functions is implemented as a set of tasks provided by the one or more processors 1304 as needed. In one example, the multitasking environment may be implemented using a time-sharing program 1320 that hands over control of the processor 1304 between different tasks, whereby each task returns control of the one or more processors 1304 to the time-sharing program 1320 upon completion of outstanding operations and / or in response to inputs such as interrupts. When a task has control of the one or more processors 1304, the processing circuit is effectively specialized for the purpose addressed by the function associated with the controlling task. The time-sharing program 1320 may include an operating system, a main loop that transfers control in a round-robin manner, a function that allocates control of one or more processors 1304 according to function priority, and / or an interrupt-operated main loop that responds to external events by providing control of one or more processors 1304 to processing functions.

[0066] In one embodiment, apparatus 1300 includes or operates as a wireless charging device having a battery charging power supply coupled to a driver circuit, a plurality of charging cells, and a controller that may be included in one or more processors 1304. The plurality of charging cells may be configured to provide a charging surface. In each charging cell, at least one transmitting coil may be configured to direct an electromagnetic field through a charge transmission area. The driver circuit may be configured to provide a charging current to the transmitting coil. Apparatus 1300 includes a wireless interface configured to transmit and receive RFID signals. The controller may be configured to transmit an interrogation signal configured to stimulate the RFID tag via the wireless interface when the rechargeable device is initially placed on or near the surface of the wireless charger, refrain from initiating wireless charging of the rechargeable device if a response to the interrogation signal is received, and negotiate a charging configuration if no response to the interrogation signal is received.

[0067] In some embodiments, the apparatus 1300 includes an antenna circuit that configures one or more of the transmission coils. The one or more coils may be configured to receive a charging current when the wireless charger is charging the rechargeable device. The controller may be configured to configure the antenna circuit to include the one or more coils based on the position of the rechargeable device relative to the surface of the wireless charger.

[0068] In some embodiments, the apparatus 1300 includes an antenna circuit including a loop that surrounds one or more coils of the wireless charger. The one or more coils may be configured to receive a charging current when the wireless charger is charging the rechargeable device. The controller may be configured to select the one or more coils based on the position of the rechargeable device relative to the surface of the wireless charger.

[0069] In some implementations, the storage 1306 holds instructions and information, the instructions configured to cause the controller to transmit an interrogation signal over the first wireless interface configured to stimulate the RFID tag, refrain from participating in wireless charging when a response to the interrogation signal is received, and negotiate a charging configuration if no response to the interrogation signal is received. The first wireless interface may be provided on the wireless charger. The interrogation signal may be transmitted when the rechargeable device is initially placed on or near the surface of the wireless charger.

[0070] In one example, the instructions may cause the controller to transmit an interrogation signal through an antenna comprising one or more coils of the wireless charger. The one or more coils may be configured to receive a charging current when the wireless charger is charging the rechargeable device. The instructions may cause the controller to select one or more coils based on a position of the rechargeable device relative to a surface of the wireless charger. The instructions may cause the controller to configure the charging current according to a charging setting if no response signal to the interrogation signal is received.

[0071] In another example, the instructions may cause the controller to transmit an interrogation signal through an antenna configured as a loop surrounding one or more coils of the wireless charger. The one or more coils may be configured to receive a charging current when the wireless charger is charging a rechargeable device. The first wireless interface may be one of multiple wireless interfaces provided on the wireless charger. Each wireless interface in the multiple wireless interfaces may be coupled to an associated antenna such that different portions of a surface of the wireless charger are surrounded by different antennas. The instructions may cause the controller to select one or more coils based on a position of the rechargeable device relative to the surface of the wireless charger. The instructions may cause the controller to negotiate a charging configuration and select one or more coils based on the positions of the rechargeable device and the different device relative to the surface of the wireless charger when a response to the interrogation signal is received from an RFID tag previously identified as associated with a different device.

[0072] In some implementations, the storage 1306 holds instructions and information configured to cause the controller to receive a wireless ping received from the wireless charger, transmit an inquiry signal over the first wireless interface after receiving the wireless ping, the inquiry signal being configured to stimulate the RFID tag, refrain from participating in the wireless charging when a response to the inquiry signal is received, and negotiate a charging configuration if no response to the inquiry signal is received.

[0073] The instructions may cause the controller to refrain from responding to a wireless ping if a response to the interrogation signal is received. The instructions may cause the controller to transmit a message configured to cause the wireless charger to terminate charging in response to the wireless ping if a response to the interrogation signal is received. The instructions may cause the controller to refrain from responding to the wireless ping or to respond to the wireless ping by transmitting a message configured to terminate charging if a response to the interrogation signal is received, and may cause the controller to display a message on a display of the rechargeable device indicating the presence of an RFID tag when a response to the interrogation signal is received.

[0074] 14 is a flowchart 1400 illustrating a wireless charging method according to certain aspects of the present disclosure. At block 1402, an interrogation signal configured to stimulate an RFID tag is transmitted by an RFID interrogation device over a first wireless interface. At block 1404, a response is awaited. At block 1406, the RFID interrogation device can refrain from participating in wireless charging if a response to the interrogation signal is received. At block 1408, the RFID interrogation device can negotiate charging settings if a response to the interrogation signal is not received.

[0075] In certain implementations, the wireless charger operates as an interrogation device, and the first wireless interface is provided within the wireless charger. The interrogation signal may be transmitted when the rechargeable device is initially placed on or near the surface of the wireless charger. In some examples, the interrogation signal may be transmitted via an antenna comprising one or more coils of the wireless charger. The one or more coils may be configured to receive a charging current when the wireless charger is charging the rechargeable device. The one or more coils may be selected based on the position of the rechargeable device relative to the surface of the wireless charger. The charging current may be configured according to a charging setting if no response signal to the interrogation signal is received.

[0076] In a particular example, the interrogation signal may be transmitted via an antenna configured as a loop surrounding one or more coils of the wireless charger. The one or more coils may be configured to receive a charging current when the wireless charger is charging the rechargeable device. In one example, the first wireless interface is one of multiple wireless interfaces provided on the wireless charger. Each wireless interface in the multiple wireless interfaces may be coupled to an associated antenna such that different portions of a surface of the wireless charger are surrounded by different antennas. The one or more coils may be based on the position of the rechargeable device relative to the surface of the wireless charger.

[0077] In one example, the wireless charger can negotiate a charging configuration when a response to an interrogation signal is received from an RFID tag previously identified as associated with a different device. One or more coils enclosed in a loop of the antenna can be selected based on the location of the rechargeable device and the different device relative to the surface of the wireless charger.

[0078] In a particular implementation, the rechargeable device operates as an interrogation device, and the first wireless interface is provided within the rechargeable device. The interrogation signal can be transmitted upon receiving a wireless ping from the wireless charger. The rechargeable device can refrain from responding to the wireless ping if a response to the interrogation signal is received. The rechargeable device can transmit a message configured to cause the wireless charger to terminate charging in response to the wireless ping if a response to the interrogation signal is received. The rechargeable device can refrain from responding to the wireless ping if a response to the interrogation signal is received. The rechargeable device can respond to the wireless ping by transmitting a message configured to cause charging to terminate if a response to the interrogation signal is received. The rechargeable device may display a message on a display of the rechargeable device. The message can indicate the presence of an RFID tag if a response to the interrogation signal is received.

[0079] Some examples are described in the following numbered sections. 1. A method for wireless charging, comprising the steps of: transmitting an inquiry signal via a first wireless interface configured to stimulate an RFID tag or an NFC tag; prohibiting participation in wireless charging if a response to the inquiry signal is received; and negotiating a charging configuration if a response to the inquiry signal is not received.

[0080] 2. The method of item 1, wherein the first wireless interface is provided in a wireless charger, and the interrogation signal is transmitted when a rechargeable device is first placed on or near the surface of the wireless charger.

[0081] 3. The method of item 2, further comprising transmitting the interrogation signal via an antenna including one or more coils of the wireless charger, the one or more coils being configured to receive a charging current when the wireless charger is charging the rechargeable device.

[0082] 4. The method of claim 3, further comprising selecting the one or more coils based on a position of the rechargeable device relative to a surface of the wireless charger.

[0083] 5. The method of claim 3 or 4, further comprising configuring the charging current according to the charging setting if no response signal to the inquiry signal is received.

[0084] 6. The method of item 2, further comprising transmitting the interrogation signal via an antenna configured as a loop surrounding one or more coils of the wireless charger, the one or more coils being configured to receive a charging current when the wireless charger is charging the rechargeable device.

[0085] 7. The method of item 6, wherein the first wireless interface is one of a plurality of wireless interfaces provided on the wireless charger, and each wireless interface of the plurality of wireless interfaces is coupled to an associated antenna such that different portions of a surface of the wireless charger are surrounded by different antennas.

[0086] 8. The method of item 6 or item 7, further comprising selecting the one or more coils based on a position of the rechargeable device relative to a surface of the wireless charger.

[0087] 9. The method of any of items 6 to 8, further comprising the step of negotiating a charging configuration if a response to the interrogation signal is received from an RFID tag previously identified as associated with a different device, and selecting the one or more coils based on the positions of the rechargeable device and the different device relative to a surface of the wireless charger.

[0088] 10. The method according to any one of items 1 to 9, wherein the first wireless interface is provided in a rechargeable device, and the inquiry signal is transmitted upon receiving a wireless ping from the wireless charger.

[0089] 11. The method of claim 10, further comprising the step of refraining from responding to the wireless ping if a response to the inquiry signal is received.

[0090] 12. The method of item 10 or item 11, further comprising the step of sending a message configured to cause the wireless charger to terminate charging in response to the wireless ping if a response to the inquiry signal is received.

[0091] 13. The method of any of items 10 to 12, further comprising the steps of: responding to the wireless ping by sending a message configured to refrain from responding to the wireless ping or to terminate charging if a response to the interrogation signal is received; and displaying a message on a display of the rechargeable device, the message indicating the presence of an RFID tag if a response to the interrogation signal is received.

[0092] 14. A wireless charging device comprising: a plurality of transmitting coils; a driver circuit configured to supply charging current to the plurality of transmitting coils; a wireless interface configured to transmit and receive RFID or NFC signals; and a controller configured to: transmit an interrogation signal via the wireless interface configured to stimulate an RFID tag or NFC tag when a rechargeable device is initially placed on or near a surface of the wireless charging device; refrain from initiating wireless charging of the rechargeable device if a response to the interrogation signal is received; and negotiate a charging configuration if no response to the interrogation signal is received.

[0093] 15. The wireless charging device of item 14, further comprising an antenna circuit including one or more coils in the plurality of transmission coils, the one or more coils configured to receive a charging current when the wireless charging device is charging the rechargeable device, and the controller configured to include the one or more coils in the antenna circuit based on the position of the rechargeable device relative to a surface of the wireless charging device.

[0094] 16. The wireless charging device of item 14, further comprising an antenna circuit including a loop surrounding one or more coils of the wireless charging device, the one or more coils configured to receive a charging current when the wireless charging device is charging the rechargeable device, and the controller configured to select the one or more coils based on the position of the rechargeable device relative to a surface of the wireless charging device.

[0095] 17. A processor-readable storage medium having stored thereon instructions that, when executed by at least one processor of a processing circuit, cause the processing circuit to: receive a wireless ping from a wireless charger; transmit an interrogation signal configured to stimulate an RFID tag or an NFC tag via a first wireless interface after receiving the wireless ping; refrain from participating in wireless charging if a response to the interrogation signal is received; and negotiate a charging configuration if a response to the interrogation signal is not received.

[0096] 18. The processor-readable storage medium of item 17, wherein the instructions further cause the processing circuit to refrain from responding to the wireless ping if a response to the interrogation signal is received.

[0097] 19. The processor-readable storage medium of item 17, wherein the instructions further cause the processing circuit to transmit a message configured to cause the wireless charger to terminate charging in response to the wireless ping if a response to the inquiry signal is received.

[0098] 20. A processor-readable storage medium as described in any of items 17 to 19, wherein the instructions further cause the processing circuit to respond to the wireless ping by sending a message configured to refrain from responding to the wireless ping or to terminate charging if a response to the interrogation signal is received, and to display a message on a display of the rechargeable device, the message indicating the presence of an RFID tag if a response to the interrogation signal is received.

[0099] The foregoing description is provided to enable those skilled in the art to practice the various embodiments described herein. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments. Therefore, the claims are not intended to be limited to the embodiments set forth herein but are to be accorded the full scope consistent with the language of the claims. Reference to an element in the singular shall mean "one or more," not "one and only," unless expressly stated otherwise. The term "some" refers to one or more, unless otherwise specified. All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or later become known to those skilled in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is expressly recited in the claims. A claim element is not to be construed under 35 U.S.C. § 112, Chapter 6, unless the element is expressly recited by the phrase "means for" or, in the case of a method claim, by the phrase "step for."

Claims

1. 1. A method for wireless charging, comprising: transmitting an interrogation signal via a first wireless interface, the interrogation signal being configured to stimulate a radio frequency identification (RFID) tag; prohibiting participation in wireless charging when a response to the inquiry signal is received; negotiating a charging configuration if no response to the inquiry signal is received; the first wireless interface is provided on a wireless charger, and the interrogation signal is transmitted when a rechargeable device is initially placed on or near the wireless charger; further comprising transmitting the interrogation signal via an antenna configured as a loop surrounding one or more coils of the wireless charger, the one or more coils being configured to receive a charging current when the wireless charger is charging the rechargeable device; and negotiating a charging configuration if a response to the interrogation signal is received from an RFID tag previously identified as associated with a different device; selecting the one or more coils based on a position of the rechargeable device and the different device relative to a surface of the wireless charger.

2. 10. The method of claim 1, further comprising transmitting the interrogation signal via an antenna including one or more coils of the wireless charger, the one or more coils configured to receive a charging current when the wireless charger is charging the rechargeable device.

3. The method of claim 2 , further comprising selecting the one or more coils based on a position of the rechargeable device relative to a surface of the wireless charger.

4. The method of claim 2 , further comprising configuring the charging current according to the charging setting if no response signal to the interrogation signal is received.

5. 2. The method of claim 1, wherein the first wireless interface is one of a plurality of wireless interfaces provided on the wireless charger, and each wireless interface of the plurality of wireless interfaces is coupled to an associated antenna such that different portions of a surface of the wireless charger are surrounded by different antennas.

6. The method of claim 1 , further comprising selecting the one or more coils based on a position of the rechargeable device relative to a surface of the wireless charger.

7. The method of claim 1 , wherein the first wireless interface is provided in a rechargeable device, and the inquiry signal is transmitted upon receiving a wireless ping from the wireless charger.

8. 8. The method of claim 7, further comprising refraining from responding to said wireless ping if a response to said inquiry signal is received.

9. 8. The method of claim 7, further comprising: if a response to the interrogation signal is received, sending a message in response to the wireless ping configured to cause the wireless charger to terminate charging.

10. further, if a response to the inquiry signal is received, responding to the wireless ping by transmitting a message configured to refrain from responding to the wireless ping or to terminate charging; and displaying a message on a display of the rechargeable device, the message indicating the presence of an RFID tag if a response to the interrogation signal is received.

11. A wireless charging device, A plurality of transmit coils; a driver circuit configured to provide a charging current to the plurality of transmit coils; a wireless interface configured to transmit and receive radio frequency identification (RFID); a controller, transmitting an interrogation signal via the wireless interface configured to stimulate an RFID tag when a rechargeable device is initially placed on or near the surface of the wireless charging apparatus; refraining from initiating wireless charging of the rechargeable device if a response to the interrogation signal is received; a controller configured to negotiate a charging configuration if no response to the inquiry signal is received; an antenna circuit configured as a loop surrounding one or more coils of the wireless charging device, the antenna circuit transmitting the interrogation signal; the one or more coils are configured to receive a charging current when the wireless charging apparatus is charging the rechargeable device; The controller negotiating a charging configuration if a response to the interrogation signal is received from an RFID tag previously identified as associated with a different device; 10. A wireless charging device configured to select the one or more coils based on a position of the rechargeable device relative to a surface of the wireless charging device.

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