Patent Publication Number: US-11381120-B2

Title: Wireless charging interference mitigation

Description:
This application claims the benefit of provisional patent application No. 62/931,469, filed Nov. 6, 2019, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to vehicle systems, and, more particularly, to interactions between vehicle remote keyless systems and wireless power systems. 
     BACKGROUND 
     Vehicles are sometimes provided with remote keyless systems. Remote keyless systems allow users with electronic keys operating at wireless communications frequencies to wirelessly control vehicle door locks and vehicle ignition functions. 
     SUMMARY 
     Challenges may arise when using remote keyless systems in the presence of other wireless equipment. If care is not taken, for example, a wireless power system that is operated in the vicinity of a remote keyless system may degrade remote keyless system performance. 
     An electronic device such as a portable electronic device has wireless power receiving circuitry. During wireless power transfer operations, wireless power signals are transmitted from wireless power transmitter circuitry to the wireless power receiving circuitry to charge a battery in the electronic device. A vehicle has a vehicle remote keyless system that transmits vehicle remote keyless system beacons. A key receives the beacons and responds with key codes to unlock doors and enable a vehicle ignition in the vehicle. The wireless power transmitter circuitry may be located in the vicinity of the vehicle. During wireless power transfer operations, there is a risk that wireless power signals from the wireless power transmitter circuitry could interfere with the reception of the vehicle keyless system beacons by the key. 
     To ensure that beacons are satisfactorily received, conditions in which there is a risk of interference are detected and corresponding interference mitigation operations are performed. 
     Interference risk detection involves detection of vehicle remote keyless system beacons, detection of key codes transmitted by the key in response to received beacons, monitoring of vehicle location and comparisons of measured device locations to stored vehicle location information, monitoring of whether the electronic device has paired wirelessly with the vehicle, using an inertial measurement unit or other input-output device to determine whether the electronic device is experiencing motion representative of vehicular travel, and/or other operations to determine when a risk of interference is present. 
     Interference mitigation operations are used to ensure that the vehicle remote keyless system can be used to operate the vehicle. Interference mitigation operations include prompting a user to disable wireless power transfer operations or automatically inhibiting wireless power transfer operations, adjusting the waveform of transmitted wireless power signals, adjusting the frequency of transmitted wireless power signals (e.g., to a frequency that is at least not the same as the wireless beacon frequency), and other operations that allow the key to receive transmitted beacons and that may allow wireless power operations to take place simultaneously with vehicle remote keyless system operations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative system with a vehicle and key in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of illustrative electronic equipment in accordance with an embodiment. 
         FIG. 3  is a diagram of an illustrative system with wireless power transfer capabilities and vehicle remote keyless system capabilities in accordance with an embodiment. 
         FIG. 4  is a flow chart of illustrative operations involved in operating a system of the type shown in  FIG. 3  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A vehicle is provided with a remote key system that allows a user to wirelessly enable operations such as a vehicle unlock and ignition. The vehicle system has one or more beacon transmitters to transmit wireless vehicle remote keyless system beacons. A user has a key that detects the beacons. The key may be a key fob, a key card, or a key system built into other equipment such as a wristwatch or cellular telephone. 
     Exemplary vehicle remote keyless system beacons are wireless signals at frequencies of typically 125 to 134 kHz, more generally within a range of 100 to 145 kHz. In response to detecting signals (hereinafter beacon(s) from the vehicle remote keyless system beacon transmitter, the key transmits key signals using a radio-frequency signal. Exemplary keys transmit wireless signals at frequencies of 300 to 1000 MHz. The key signals represent, in some examples, key codes that cause the remote key system to unlock vehicle doors and enable the vehicle ignition of the vehicle. The user may then enter the vehicle through the vehicle&#39;s unlocked doors and may start the vehicle&#39;s engine by pressing a start button in the vehicle. 
     An electronic device in the vehicle or near the vehicle (e.g., within 10 m or within 20 m) has wireless power transmitting circuitry that transmits wireless power signals to compatible devices. Examples of compatible devices include wristwatches, cellular telephones, removable battery cases, and other battery-powered electronic devices with wireless power receiving circuitry. In an embodiment, an electronic device in or near a vehicle that transmits wireless power is an accessory that draws power from the vehicle&#39;s power outlets such as Universal Serial Bus (USB) charging apparatuses (e.g., a charging pad or other accessory that is coupled to a power source in a vehicle). A removable battery case in or near a vehicle may also serve as a wireless power transmitter (e.g., battery case circuitry may serve as a transmitter when the battery case is located in or near a vehicle while transmitting power to a cellular telephone or other electronic device that is coupled to the battery case). Wireless power signals may be transmitted, for example, at frequencies of 110 kHz to 205 kHz. The wireless power signals are received by the wireless power receiving circuitry and used to charge a battery in the portable electronic device. 
     A transmitted wireless power signal may have a frequency that is identical to or close to a frequency associated with the vehicle remote keyless system beacons. In some scenarios, wireless power transmissions therefore poses a risk of interference with the beacons being transmitted by, the vehicle remote key system. This can impact the ability of a user to open vehicle doors and enable a vehicle&#39;s ignition using a key. To prevent undesired interference between wireless power operations and vehicle remote key system operations, detection operations can be used to detect the presence of potential interference conditions. If a risk of interference is detected, actions may be taken to mitigate the effects of wireless power transmissions on the operation of the vehicle remote key system. In this way, the user will be able to satisfactorily operate the vehicle using the key. In some scenarios, wireless power transfer operations may coexist with vehicle remote keyless system operations, meaning that both the vehicle remove keyless system and the wireless charging system can function in the presence of one another. 
       FIG. 1  is a system diagram of an illustrative system that includes a vehicle and an associated wireless key device. As shown in  FIG. 1 , system  10  includes vehicle  20 . Vehicle  20  includes a vehicle body, a motor, steering equipment, brakes, and other vehicle components. Vehicle  20  may be an automobile, truck, motorcycle, or other vehicle. 
     As shown in  FIG. 1 , vehicle  20  includes a wireless key system such as vehicle remote keyless system  28 . System  28  includes radio-frequency transmitter  22 , radio-frequency receiver  24 , and processing circuitry  26  (sometimes referred to as control circuitry). Radio-frequency transmitter  22  transmits vehicle remote keyless system beacons to key  44  using an antenna (see, e.g., antennas  30 ). The beacons may be transmitted at any suitable beacon frequency. As an example, the beacons may be transmitted at a frequency in the range of 100-145 kHz. 
     Radio-frequency receiver  24  uses an antenna (see, e.g., antennas  30 ) to receive radio-frequency key codes from key  44  at a frequency of 315 MHz to 435 MHz, 300 MHz to 1000 MHz (1 GHz) or other suitable key code frequency. Processing circuitry  26  controls the operation of system  28  and other systems in vehicle  20  such as vehicle systems  32 . Vehicle systems  32  include door locks, ignition systems, and other devices that are controlled by processing circuitry  26 . For example, key system  28  may open door locks and enable a vehicle ignition in response to receiving key codes from key  44 . 
     Key circuitry  40  of key  44  includes antenna circuitry (see, e.g., antennas  42 ), radio-frequency receiver  34 , and radio-frequency transmitter  36 . Key circuitry  40  also includes processing circuitry  38  (sometimes referred to as control circuitry) and other components (e.g., a battery, an optional display, buttons, etc.). Processing circuitry  38  of key circuitry  40  uses radio-frequency receiver circuitry such as receiver  34  and an associated antenna (see, e.g., antennas  42 ) to monitor for incoming vehicle remote keyless system beacons. In response to detecting a beacon, processing circuitry  38  may automatically use radio-frequency transmitter circuitry such as radio-frequency transmitter  36  to transmit corresponding key codes to system  28  at a frequency of 315 MHz to 435 MHz, 300-1000 MHz, or other suitable key code frequency. System  28  adjusts vehicle systems  32  when the key codes are received. For example, system  28  can open door locks and enable an ignition system in vehicle systems  32  in response to receiving the key codes. 
     Wireless power signals may be transmitted between a wireless power charger (e.g., a mat) and a battery-operated device (e.g., a phone) in the presence of key  44  and vehicle  20 . These wireless power signals can potentially interfere with reception of beacons by key  44  and thereby prevent a user from opening and operating vehicle  20 . To help ensure satisfactory operation of vehicle remote keyless system functions, interference risk detection operations can be used to detect when a condition indicative of a risk of interference is present and appropriate interference mitigation operations can be taken in response. 
     Wireless power signals can be transmitted and/or received using equipment of the type shown in  FIG. 2 . Some or all of the circuitry of equipment  50  of  FIG. 2  may be used in forming an electronic device that is used in or near a vehicle. The electronic device may transmit wireless power and/or may receive wireless power. For example, a battery case may transmit wireless power and may optionally receive wireless power, a charging accessory such as a charging pad or puck may transmit wireless power, a cellular telephone, tablet computer, wristwatch, laptop computer, and other electronic devices can wirelessly receive power and can optionally wirelessly transmit power, etc. Accordingly, in some embodiments, a device formed from the circuitry of illustrative equipment  50  contains wireless power transmitting circuitry  62 , in other embodiments, contains wireless power receiving circuitry  70 , and in further embodiments, contains both wireless power transmitter circuitry and wireless power receiver circuitry. In general, equipment  50  may be used in a cellular telephone, a wristwatch, a tablet computer, a laptop computer, an accessory such as a computer stylus or other input-output device, other portable electronic devices, equipment that is part of an embedded system in vehicle  20 , a removable case for an electronic device (e.g., a removable cover for a tablet computer, a removable battery case for a cellular telephone or other portable device, etc.), a wireless charging pad or puck, a key (see, e.g., key  44  of  FIG. 1 ), and/or other electronic equipment. 
     Electronic equipment  50  of  FIG. 2  includes optional components. One or more of these optional components may be omitted to reduce the cost and complexity of equipment  50 . For example, when equipment  50  is used in forming part of vehicle  20 , equipment  50  contains components such as vehicle controls (see, e.g., other circuitry  88 ) different from when equipment  50  is used in forming key  44  or a user&#39;s cellular telephone (as examples). The schematic diagram of  FIG. 2  is presented as an example. 
     As shown in  FIG. 2 , equipment  50  includes control circuitry  52 . Control circuitry  52  is used to control the operation of equipment  50 . This control circuitry may include processing circuitry associated with microprocessors, power management units, baseband processors, digital signal processors, microcontrollers, and/or application-specific integrated circuits with processing circuits. The processing circuitry implements desired control and communications features in equipment  50 . For example, the processing circuitry may be used in controlling wireless power operations, processing sensor data and other data, processing user input, handling negotiations between devices, sending and receiving wireless communications (e.g., commands, beacons, sensor measurements and other data, etc.), making measurements, monitoring battery status, controlling battery charging, and otherwise controlling the operation of equipment  50 . 
     Control circuitry  52  may be configured to perform operations in equipment  50  using hardware (e.g., dedicated hardware or circuitry), firmware, and/or software. Software code for performing system operations is stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media) in control circuitry  52 . The software code may sometimes be referred to as software, data, program instructions, instructions, or code. The non-transitory computer readable storage media may include non-volatile memory such as non-volatile random-access memory (NVRAM), one or more hard drives (e.g., magnetic drives or solid state drives), one or more removable flash drives or other removable media, or the like. Software stored on the non-transitory computer readable storage media may be executed on the processing circuitry of control circuitry  52 . The processing circuitry may include application-specific integrated circuits with processing circuitry, one or more microprocessors, a central processing unit (CPU) or other processing circuitry. 
     Equipment  50  includes input-output circuitry as shown by input-output devices  76  of  FIG. 2 . Input-output devices  76  may include output devices such as display  78 , speakers for emitting sound, and other devices  84  (e.g., haptic output devices, etc.). Satellite navigation system circuitry in devices  76  such as global positioning system receiver  82  may be used to gather information on the current location of equipment  50  and its velocity. Sensors  80  may include image sensors, optical proximity sensors, three-dimensional image sensors formed from light emitters that project beams of light and corresponding image sensors that detect dots where the projected light beams strike objects, camera flash components, and/or other circuits that emit and/or detect light, ambient light sensors, force sensors, radio-frequency circuitry such as radar circuitry and/or other radio-frequency circuitry for detecting the location and movement of objects, microphones for gathering sound, touch sensors, buttons, temperature sensors, gas sensors, and/or other circuitry for detecting user input and for measuring environmental data. Sensors  80  may include inertial measurement units (e.g., accelerometers, compasses, and/or gyroscopes) for measuring the position, orientation, and/or movement of equipment  50 . In some scenarios, a satellite navigation system receiver and/or an accelerometer or other inertial measurement unit circuitry can detect when equipment  50  is traveling within a range of speeds associated with motorized vehicles (e.g., when vehicle  20  is traveling between 20 and 80 miles per hour), when equipment  50  is experiencing changes in acceleration that are within a predetermined range of accelerations indicative of the travel of vehicle  20  along a road, when equipment  50  is traveling along a mapped roadway, and/or when equipment  50  is otherwise characterized by physical activity (positions, orientations, and/or movements) indicative of operating in a moving vehicle (e.g., when equipment  50  is characterized by parameters indicative of vehicular travel). Inertial measurement units may also monitor the movement of equipment  50  when a user is walking away from a vehicle after parking. For example, measurements from an inertial measurement unit in equipment  50  (e.g., a device carried by a user) may be used to detect when a car has been parked and a user has walked a certain distance, e.g., 10 m, away from the car such that interference mitigation may no longer be required. 
     As shown in  FIG. 2 , equipment  50  includes a battery such as battery  86  to provide equipment  50  with power and, if desired, to transmit wireless power. Communications circuitry  54  includes radio-frequency transmitter circuitry  58  (e.g., a transmitter that can be tuned to a desired transmission frequency, sometimes referred to as a tuned transmitter) and/or radio-frequency receiver circuitry  56  (e.g., a receiver that can be tuned to a desired reception frequency, sometimes referred to as a tuned receiver). Transmitter circuitry  58  uses an antenna (see, e.g., antennas  60 ) to transmit wireless signals. Receiver circuitry  56  uses an antenna (see, e.g., antennas  60 ) to receive wireless signals. In some configurations, receiver circuitry  56  receives wireless signals and/or transmitter circuitry  58  transmits wireless signals using a wireless power transmitting coil and/or a wireless power receiving coil (see, e.g., coils  68  and  72 ) that is otherwise used for handling wireless power signals. Configurations in which antenna(s)  60  is separate from coil(s)  68  and coil(s)  72  may also be used. Separate antennas and coils shared with wireless power transmission circuitry may be used with receiver and transmitter circuits and may therefore sometimes be referred to as forming part of the wireless transmitter circuitry and wireless receiver circuitry of equipment  50 . Wireless communications can be transmitted and/or received at any suitable frequency (e.g., frequencies associated with vehicle remote keyless system operations when circuitry  54  is used as part of a system such as system  28  of  FIG. 1  such as frequencies of 100-145 kHz associated with keyless system beacons, frequencies of 300-1000 MHz associated with key code transmissions from a key, and/or other frequencies), frequencies associated with wireless local area networks (e.g., 2.4 GHz, 5 GHz, other WiFi® frequencies, etc.), millimeter wave frequencies (e.g., frequencies above 10 GHz), cellular telephone frequencies (e.g., 700 MHz to 2.7 GHz, and/or frequencies below 700 MHz, and/or above 2.7 GHz), personal area network frequencies (e.g., 2.4 GHz for Bluetooth®), and/or other radio frequencies for supporting wireless communications between respective electronic devices. 
     Wireless power circuitry  62  may be included in electronic equipment  50 . For example, vehicle  20 , key  44 , cellular telephones, wristwatches, battery cases, and/or other electronic devices may optionally include wireless power transmitting circuitry  64  and/or wireless power receiving circuitry  70 . Wireless power transmitting circuitry  64  has an inverter  66  that provides an alternating-current drive signal (current) to coil(s)  68  to generate wireless power signals (alternating-current electromagnetic fields). The wireless power signals may be received using wireless power receiving circuitry in a receiving electronic device. 
     The receiving electronic device may have wireless power receiving circuitry such as wireless power receiving circuitry  70  of equipment  50 . Circuitry  70  of illustrative electronic equipment  50  of  FIG. 2  includes coil(s)  72  and rectifier  74 . Using one or more coils  72 , wireless power signals are received and corresponding current flow is induced in coil(s)  72 . The current coil(s)  72  is rectified using rectifier  74  to charge battery  86  and/or to otherwise power circuitry in equipment  50 . 
       FIG. 3  is a diagram of an illustrative system  8  that contains a vehicle remote keyless system and wireless power circuitry. System  8  of  FIG. 8  includes vehicle  10 A, key  10 B, electronic device  10 C, and electronic device  10 D. Other electronic systems may contain vehicle remote keyless systems and wireless power circuitry, if desired. System  8  of  FIG. 3  is presented as an example. 
     Vehicle  10 A of  FIG. 3  may be a vehicle such as vehicle  20  of  FIG. 1  and may include equipment of the type shown in  FIG. 2 . Vehicle  10 A includes vehicle equipment such as vehicle remote keyless system  100  (see, e.g., system  28  of  FIG. 1 ). As shown in  FIG. 3  a battery case, wireless charging accessory (e.g., a charging pad or charging puck that receives wired power from vehicle  10 A), or other electronic device  10 D may be located in vehicle  10 A. In some scenarios, electronic device  10 D is located outside of vehicle  10 A but near to vehicle  10 A (e.g., within 10 m of vehicle  10 A at a location such as location  10 D′). Device  10 D contains wireless power transmitting circuitry  102  and optionally contains additional electrical equipment (see, e.g., with optional wireless power receiving circuitry of wireless power circuitry  62  and other electronic equipment  50  of  FIG. 2 ). During wireless power transfer operation, wireless power transmitting circuitry  102  may be used to transmit wireless power signals that are received by wireless power receiving circuitry  106  in electronic device  10 C (e.g., to charge a battery in device  10 C). Key  10 B includes key circuitry  104  (see, e.g., key circuitry  40  of  FIG. 1 ) and may include additional components (e.g., a display, cellular telephone transceiver circuitry, wireless local area network circuitry, sensors, etc.). Key  10 B may be a key fob, a key card, a key built into a wristwatch, cellular telephone, tablet computer, or other portable electronic device, or other suitable wireless vehicle key. 
     Electronic device  10 C includes wireless power receiving circuitry  106  (see, e.g., wireless power receiving circuitry  70  of wireless power circuitry  62  of  FIG. 2 ) and may include other circuitry (e.g., some or all of the circuitry of electronic equipment  50  of  FIG. 2 ). Electronic device  10 C may be a portable electronic device such as a cellular telephone, tablet computer, wristwatch, or other electronic equipment. 
     In order to receive wireless power from wireless power transmitting circuitry  102 , a user may place device  10 C so that wireless power receiving circuitry  106  is sufficiently close to wireless power transmitting circuitry  102  to receive wireless power signals (e.g., within less than 10 cm, less than 2 cm, less than 1 cm, or other suitable distance, or in direct contact such that the wireless power receiving device is abutting the wireless power transmitting device). If, as an example, circuitry  102  is associated with a charging surface (e.g., a surface of a wireless power charging mat, a vehicle console surface or other built-in vehicle surface that overlaps wireless power coil(s), etc.), device  10 C may be placed on the charging surface so that a wireless power receiving coil in circuitry  106  overlaps one or more corresponding wireless power transmitting coils in circuitry  102 . As another example, if circuitry  102  forms part of a removable battery case with wireless power transmitting capabilities, a user may place device  10 C in the removable battery case so that the wireless power receiving coil of circuitry  106  is electromagnetically coupled to one or more associated wireless power transmitting coils in circuitry  102 . 
     When circuitry  106  and wireless power transmitting circuitry  102  are placed adjacent to each other or are otherwise located sufficiently close together to allow wireless power signals to be conveyed from circuitry  102  to circuitry  106 , wireless power may be transferred. During wireless power transmission, the inverter in circuitry  102  drives alternating-current drive signals (e.g., signals at a frequency within a range of 110 kHz to 205 kHz or other suitable frequency) through one or more wireless power transmitting coils in circuitry  102  to transmit wireless power signals to circuitry  106 . The alternating-current drive signals may be square wave signals, sinusoidal signals, signals with asymmetric waveforms, pulses with any suitable duty cycle, or other suitable alternating-current signals. Circuitry  106  uses corresponding coil(s) and rectifier circuitry to receive the wireless power signals and convert these signals into a power supply voltage for device  10 C (e.g., to charge the battery in device  10 C and/or to power other circuitry in device  10 C). 
     Vehicle  10 A uses remote keyless system  100  to wirelessly transmit vehicle remote keyless system beacons. These beacons may, as an example, have a frequency in a range of 100 to 145 kHz (as an example). Key  10 B uses key circuitry  104  to monitor for the transmitted beacons and, if a beacon is received, key  10 B uses key circuitry  104  to transmit corresponding key codes to remote keyless system  100  in response. Key  10 B will not receive the beacons if key  10 B is far away from vehicle  10 A or if interference is present. 
     The presence of wireless power signals associated with the transfer of power from circuitry  102  to circuitry  106  has the potential to create interference that can prevent key circuitry  104  from satisfactorily receiving the wireless beacons from system  100 . To mitigate situations in which key  104  is unable to receive beacons from system  100 , the control circuitry of system  8  detects when interference is present, or likely to be present and takes suitable actions to mitigate the undesired effects of interference. 
     A user may carry both device  10 C and key  10 B (and, in some scenarios, key  10 B can be implemented on device  10 C). Because key  10 B and device  10 C are often in close proximity (e.g., because key  10 B and device  10 C are both in a user&#39;s pocket and/or because key  10 B and device  10 C are being carried in a bag of the user), interference risk can be detected by detecting conditions in which key  10 B is near to vehicle  10 A (in which case device  10 C is also likely close to vehicle  10 A and circuitry  102 ) and/or by detecting conditions in which device  10 C is near to vehicle  10 A (in which case key  10 B is also likely close to vehicle  10 A and circuitry  102 ). These interference scenarios can arise whether circuitry  102  is embedded into vehicle  10 A or is otherwise associated with vehicle  10 A or whether circuitry  102  is in a battery case or other device that is separate from vehicle  10 A and is coupled to or otherwise associated with device  10 C. 
     The control circuitry of system  8  that performs interference risk detection operations and interference mitigation operations includes control circuitry such as control circuitry  52  of  FIG. 2 . This control circuitry includes control circuitry located in an electronic device (e.g., a device such as device  10 D that is separate from vehicle  10 A and that is located in or near vehicle  10 A) that contains wireless power transmitting circuitry  102 , control circuitry that is located in key  10 B, and/or control circuitry that is located in electronic device  10 C. Control circuitry in different devices communicates wirelessly and/or using wired communications paths (when present). 
     Illustrative interference detection operations and interference mitigation operations that may be performed in system  8  of  FIG. 3  are shown in  FIG. 4 . 
     During the operations of block  200 , the control circuitry of system  8  (e.g., an electronic device such as device  10 C, device  10 D, and/or other circuitry in  FIG. 3 ) performs detection operations. During these detection operations, the control circuitry monitors the operation of system  8  to detect a condition that is associated with a possibility that wireless power signals from circuitry  102  will interfere with vehicle remote keyless system beacons being transmitted by system  100 . If no interference possibility is detected (e.g., if the control circuitry determines that wireless power signals from circuitry  102  are not likely to create interference that hinders the reception of beacons by keys such as key  10 B), no action need be taken (e.g., wireless power transmission may be permitted to continue uninterrupted). In response to detection of possibility of interference, however, the control circuitry of system  8  (e.g., an electronic device such as device  10 C, device  10 D, and/or other circuitry in  FIG. 3 ) may, during the operation of block  202 , take action to mitigate interference. In particular, during the operations of block  202 , interference mitigation operations may be performed by the control circuitry. The mitigation operations help remove factors that create interference, thereby improving key circuitry  104 &#39;s reception of beacons and transmissions to those beacons with wireless key codes. 
     In embodiments, one or more interference detection techniques are used by the control circuitry of device  10 C, device  10 D, and/or other control circuitry of system  8 . 
     In a first illustrative arrangement for a first embodiment, which may sometimes be referred to as a synchronous detection scheme, the control circuitry of device  10 C, device  10 D, or other circuitry in system  8  uses radio-frequency receiver circuitry (see, e.g., circuitry  54 ) to monitor for the presence of the wireless beacons transmitted by remote keyless system  100 . A coil that serves as an antenna for beacon signals and that is also sometimes used to receive and/or transmit wireless power signals or a separate wireless receiving structure (e.g., separate antenna(s), separate coil(s), one, two, or three orthogonal coils such as coils that serve as antennas separate from the wireless power receiving coil) and associated radio-frequency receiver circuitry are included in device  10 C, device  10 D, or other equipment in system  8 . The receiving structure and radio-frequency receiver circuitry are configured to receive beacons at the wireless beacon frequency (e.g., a frequency of 100-145 kHz) and are thus used to automatically monitor for beacon transmissions. If desired, the radio-frequency receiver that is used to monitor for the beacon signals can receive and analyze digital data in the beacon signals to help confirm that the beacon signals are associated with a remote keyless system. 
     Wirelessly transmitted beacons have a limited range (e.g., less than 20 meters). If beacons are detected during the operations of block  200 , it can be concluded that the detection circuitry (e.g., the antenna and associated radio-frequency receiver circuitry of device  10 C, device  10 D, or other circuitry in system  8 ) that has detected the beacons is near to system  100  (e.g., within 20 meters, as an example). For example, in response to detecting beacons from system  100  using an antenna and radio-frequency receiver circuitry in device  10 C or device  10 D that is sensitive to wireless signals in the range of 100-145 kHz), device  10 C or device  10 D can conclude that device  10 C and/or device  10 D is within the wireless beacon range of vehicle  10 A and system  100 . The radio-frequency receiver can be a homodyne circuit, a heterodyne circuit, or other tuned demodulator. Circuitry  102  and device  10 D are in or near vehicle  10 A, so by detecting that device  10 C or device  10 D is within wireless range of the beacons of system  10 , device  10 C or device  10 D can conclude that device  10 C and/or device  10 D is sufficiently close to system  100  and circuitry  102  of vehicle  10 A that there is a risk that any transmission of wireless power from circuitry  102  to circuitry  106  will create wireless power signals that will interfere with the wireless beacon signals being transmitted by system  100  and thereby impact reception of the wireless beacon signals by key  10 B. 
     In a second illustrative arrangement for the first embodiment, device  10 C or device  10 D uses wireless receiver circuitry (see, e.g., radio-frequency receiver circuitry  56  of communications circuitry  54  in  FIG. 2 ) to monitor for the presence of wireless key codes. When key  10 B receives wireless beacons from system  100 , key circuitry  104  responds by transmitting key codes (e.g., key codes at a frequency of 315 MHz to 435 MHz, 300-1000 MHz, or other suitable key code frequency). The wireless receiver circuitry of device  10 C or device  10 D has an antenna and radio-frequency receiver configured to detect transmission of the key codes by key  10 B. When key codes are detected, device  10 C, or device  10 D can conclude that key  10 B is within range of system  100  (because key  10 B is likely transmitting the key codes in response to receiving beacons) and can conclude that device  10 C or device  10 D is near to key  10 B and system  100  (because device  10 C or device  10 D is receiving the transmitted codes). By detecting that key  10 B has likely been triggered by a nearby vehicle, device  10 C or device  10 D can determine that there is a risk that wireless power transmission operations (e.g., receipt of wireless power by wireless power receiving circuitry  106  from wireless power transmitting circuitry  102 ) will cause undesired interference, for example, by impacting reception of the beacon signals by key  10 B). 
     In a second embodiment, which may sometimes be referred to as a non-synchronous detection technique, envelope detection technique, or peak detection technique, the control circuitry of device  10 C, device  10 D, or other circuitry in system  8  (e.g., circuitry  54  of  FIG. 2 ) includes radio-frequency signal peak detector circuitry to monitor for the presence of the wireless beacons transmitted by remote keyless system  100 . The communications circuitry of device  10 C or device  10 D may, for example, include receiver circuitry  56  that has analog and/or digital circuitry that is configured to implement a peak detector. The peak detector is configured to measure a peak in the transmitted or received wireless power signal that is above a baseline level without the presence of beacon signals. For example, in an arrangement in which the peak detector is coupled to a wireless power receiving coil that is otherwise being used to receive wireless power signals, the peak detector can detect signal peaks corresponding to beacons from system  100  that appear above the wireless power signal in the coil. One, two, or three separate orthogonal coils may also be used in receiving signals. If the measured signal magnitude (e.g., the measured maximum of the peak-to-peak voltage of a sample of the received signals at the beacon frequency) exceeds a predetermined threshold (e.g., a predetermined amount above the wireless power signal level or other baseline amount), the control circuitry can conclude that the beacon signals are present. 
     With the second embodiment, the radio-frequency receiver circuitry of device  10 C or device  10 D uses a receiving structure (e.g., a shared antenna(s), a separate antenna(s), a shared wireless power receiving coil(s), a coil that is shared between wireless power transmission and wireless signal receiving operations, or a separate coil(s)) and associated radio-frequency signal peak detector to monitor for signals at the beacon frequency that are characterized by a magnitude that exceeds a predetermined threshold value (e.g., a predetermined peak voltage). If desired, a bandpass filter may be coupled in series between the antenna and the peak detector. The bandpass filter can be configured to block all signals except signals within the possible range of beacon signal frequencies. For example, the bandpass filter may pass signals in a range of 100-145 kHz, may have a first pass band at 125 kHz (to correspond with a 125 kHz beacon) and a second pass band at 134 kHz (to correspond with a 134 kHz beacon) and/or may otherwise be configured to filter out signals other than those at beacon frequencies. If a beacon is transmitted, the peak detector will detect a wireless signal that exceeds the predetermined threshold and, in response to detecting that the peak signal strength at the beacon frequency has exceeded the predetermined threshold (predetermined peak voltage), it can be concluded that beacon signals are being transmitted. 
     In the second embodiment, it can be concluded that the peak detection circuitry (e.g., the antenna and associated peak detector of device  10 C, device  10 D, or other circuitry in system  8 ) is near to system  100  if beacons are detected. For example, in response to detecting beacons from system  100  using an antenna and radio-frequency peak detector in device  10 C or device  10 D that is sensitive to wireless signals in the range of 100-145 kHz, device  10 C or device  10 D can conclude that device  10 C or device  10 D is within wireless beacon range of vehicle  10 A and system  100 . Because circuitry  102  is in or near vehicle  10 A, device  10 C and/or device  10 D can conclude, based on the detection of the beacons, that device  10 C and/or device  10 D is sufficiently close to system  100  and circuitry  102  of vehicle  10 A that there is a risk that transmission of wireless power from circuitry  102  to circuitry  106  will interfere with the wireless beacon signals (and thereby prevent satisfactory reception of the wireless beacon signals by key  10 B). 
     In a third embodiment, which may sometimes be referred to as an indirect detection technique, information on whether or not there is an interference risk is gathered by monitoring for conditions indicating that device  10 C is nearby vehicle  10 A. When device  10 C is in the vicinity of vehicle  10 A, circuitry  102  is likely within range of circuitry  106 . As a result, wireless power transmissions may produce radio-frequency wireless power signals that interfere with the reception of beacons from system  100  by key  10 B. 
     In a first illustrative arrangement for the third embodiment, the location of vehicle  10 A can be monitored (e.g., using satellite navigation system circuitry such as global positioning system receiver  82  of  FIG. 2  in device  10 C). Whenever a user parks vehicle  10 A, the vehicle&#39;s speed will drop from a speed associated with vehicular travel to zero, indicating that the vehicle is parked. By monitoring the speed of receiver  82 , control circuitry (e.g., control circuitry in system  8  such as control circuitry in device  10 C and/or other portions of system  8  can determine when vehicle  10 A has parked and, from the location gathered by receiver  82 , can determine where vehicle  10 A has been parked. The control circuitry of system  8  (e.g., control circuitry in device  10 C) can maintain vehicle parking location information indicating where vehicle  10 A has been parked. During subsequent operations of device  10 C, satellite navigation system circuitry such as global positioning system receiver  82  of  FIG. 2  can be used to monitor the location of device  10 C (e.g., after a user has exited vehicle  10 A and is traveling by foot). The control circuitry of device  10 C and/or other control circuitry of system  8  can periodically compare the known location of the user&#39;s parked vehicle (vehicle  10 A) and the user&#39;s known location (the known location of device  10 C). If device  10 C is determined to be far from vehicle  10 A, it can be concluded that there is no risk that wireless power reception by device  10 C will interfere with beacons being sent by vehicle  10 A to key  10 B. In response to determining that device  10 C has returned to the vicinity of vehicle  10 A, however, it can be concluded that there is a risk that wireless power reception by device  10 C will interfere with the beacons being sent by vehicle  10 A to key  10 B. 
     In a second illustrative arrangement for the third embodiment, control circuitry in system  8  such as control circuitry in device  10 C can monitor the communications links that device  10 C has established with vehicle  10 A (e.g., by monitoring communications circuitry in device  10 C such as communications circuitry  54  of  FIG. 2  to determine whether device  10 C has paired with vehicle  10 A). It can be concluded that device  10 C is in the vicinity of vehicle  10 A (e.g., that device  10 C is within 20 m or other given short distance of vehicle  10 A and that there is therefore an interference risk) if any short-range wireless communications links have been established between device  10 C and vehicle  10 A (e.g., a short-range personal area network link such as a Bluetooth® link, a wireless local area network link such as an IEEE 802.11 link, or other wireless communications links for supporting wireless operations in which the capabilities of device  10 C are shared with vehicle  10 A such as Apple CarPlay® operations, a near-field communications link at a frequency of 13.56 MHz or other suitable near-field communications frequency, or other short-range wireless link that wirelessly pairs device  10 C with vehicle  10 A) and/or if device  10 C is paired with vehicle  10 A by virtue of establishing a wired communications link (e.g., for supporting a wired operations in which the capabilities of device  10 C are shared with vehicle  10 A such as wired Apple CarPlay® functions). 
     In a third illustrative arrangement for the third embodiment, control circuitry in system  8  such as control circuitry in device  10 C uses input-output devices (e.g., input-output devices such as sensors  80  and/or satellite navigation system circuitry such as global positioning system receiver  82 ) to determine when device  10 C is located in or near a vehicle. In this scenario, the control circuitry may, as an example, determine when device  10 C is characterized by acceleration values, speed values, and other parameters that fall within a range of these parameters associated with vehicular travel (e.g., parameters associated with automotive capabilities). Consider, as an example speed. A user typically walks or runs at speeds of less than 10 miles per hour. So when a user is experiencing speeds above 10 miles per hour, the user is likely in a moving vehicle. Similarly, acceleration values with predetermined characteristics are associated with vehicular travel (e.g., acceleration values above a predetermined minimum acceleration value, below a predetermined maximum acceleration value, and characterized by a variation in acceleration value over time within a predetermined range (due to vehicular motion along a roadway). If desired, the control circuitry can determined whether a user is located on a roadway and/or is traveling along a roadway (e.g., using map data and satellite navigation system position and/or velocity information). Using input-output devices in device  10  (e.g., an accelerometer, other inertial measurement unit circuitry, satellite, navigation system circuitry, and/or other circuitry), the motion, orientation, and/or position of device  10 C can therefore be analyzed to determine whether device  10 C is experiencing characteristics indicative of vehicular travel and is therefore likely in vehicle  10 A. Techniques such as these may also be used to determine when a user has parked a car and is still within 20 m or other short distance from the car (e.g., by measuring how many steps the user has taken after parking). 
     Any one or more of these illustrative interference risk detection techniques and/or other suitable interference risk detection techniques may be used to detect interference risk and may be used in conjunction with any one or more suitable interference mitigation techniques. 
     Illustrative interference mitigation approaches that may be used in system  8  involve changes to the transmission of wireless power signals between circuitry  102  and circuitry  106  to help prevent the wireless power signals from blocking the reception by key  10 B of the beacons being transmitted by system  100 . 
     With a first illustrative embodiment, control circuitry in device  10 C, control circuitry in vehicle  10 A, and/or other control circuitry in system  8  may automatically cease wireless power transmission operations to prevent wireless power signals from interfering with beacons from system  100 . For example, wireless power transmitting circuitry  102  may be turned off in response to detecting an interference risk so that no wireless power signals are transmitted by circuitry  102  (e.g., until the risk is no longer detected). Vehicle  10 A and/or device  10 C can turn off circuitry  102  in this way. For example, device  10 C can transmit power adjustment commands to circuitry  102  that direct circuitry  102  to lower the magnitude of transmitted power to zero. Circuitry  102  may be turned off completely in this way or, if desired, circuitry  102  may be instructed to reduce the amount of transmitted power to a small non-interfering level (e.g., an amount less than 10% or less than 3% of the maximum wireless power transmission capability of system  8  its maximum capacity, as an example). If desired, a user may be provided with an opportunity to manually turn off (or reduce) power transmission. For example, a user may be provided with an on-screen option on a touch-screen display on device  10 C or may otherwise may be prompted for input to confirm that wireless power transmission should be halted (or at least the amount of power transmitted should be reduced to a level that avoids interference or other adjustments made to avoid interference). An on-screen option may include a message such as “wireless key operation may be impacted by wireless power activities—press here to pause wireless power operations”. Voice prompts, button options, and other input-output arrangements may be used to gather user input indicating that wireless power transmission should be turned off or otherwise curtailed. Scenarios in which wireless power transmissions are turned off to prevent interference allow key  10 B to be used to operate vehicle  10 A, but interrupt wireless power transfer because no wireless power signals are being transmitted. 
     In a second illustrative embodiment, circuitry  102  is directed by the control circuitry of system  8  to transmit wireless power signals intermittently. As an example, circuitry  102  may be configured to alternate between first and second operating modes in accordance with a given duty cycle (e.g., a duty cycle of 50%, at least 30%, less than 70%, etc.) when it is desired to perform interference mitigation. In the first operating mode, wireless power is transmitted (e.g., wireless power transmitting circuitry  102  is active and wireless power receiving circuitry  106  is able to receive transmitted wireless power signals). During operations in the first operating mode, interference is likely present. In the second operating mode, however, wireless power transmitting circuitry  102  lowers or completely halts wireless power transmission to prevent interference. By selection of an appropriate duty cycle, beacons can be received by key  10 B during the second periods. For example, an appropriate duty cycle provides that the second periods are sufficiently long relative to the alternating first periods, such that sufficient interference-free time is available for the remote keyless system to operate without being impeded by the transmission of wireless power. The first periods and second periods may be, for example, 2.5 s long (or other suitable length such as a time period of at least 2 s, at least 3 s, less than 5 s, etc.). This length of time (e.g., 2.5 s) for the second period is sufficient for the vehicle remote keyless system to complete handshaking operations (which typically take about 30-200 ms) and to accommodate the polling interval used by vehicles in sending beacons (which may be, for example, 500 ms for some vehicles, 2000 ms for other vehicles, etc.). In an illustrative configuration, the duty cycle can be variable, that is, the off time can be varied between 250 ms to 2500 ms. Arrangements in which the duty cycle is fixed (e.g., the off time has a fixed value of between 250 and 2500 ms) may also be used. An appropriate duty cycle provides that the second periods are not so long such that wireless power operations must be completely restarted (e.g., circulating currents are not drained), so that a meaningful amount of wireless power is transmitted between circuitry  102  and circuitry  106  to support operations of the receiving device over the course of the duty cycles as the wireless power transmitter and receiver continue to operate in-vehicle. This second illustrative embodiment therefore permits remote keyless system operations and wireless power transfer operations to coexist. 
     In a third illustrative embodiment, interference mitigation operations involve adjusting parameters associated with the alternating-current drive signal used by inverter  66  to drive signals to coil(s)  68  ( FIG. 2 ). The alternating-current drive signal may be, for example, an alternating-current waveform having frequency f. A first example of a parameter that may be adjusted to reduce interference is the shape of the waveform used for the alternating-current drive signal and the resulting wireless power signal (e.g., whether the waveform is a square wave, a sinusoidal signal, a symmetric or asymmetric waveform with another shape, a pulse train with pulses of a particular duty cycle, and/or other changes to the shape of the current signal flowing through coil(s)  68  and the resulting wireless power signal transmitted by circuitry  102 ). A second example of a parameter that may be adjusted to reduce interference is the frequency f of the alternating-current drive signal and corresponding wireless power signal. Frequency f lies within a frequency range of 110 kHz to 205 kHz (as an example). To prevent interference, frequency f can be shifted to a particular extreme of this range (e.g., 110 kHz or 205 kHz), may alternate between first and second frequencies in this range, may be swept repeatedly between first and second frequencies, may hop between two or more different frequencies in a predetermined pattern or random pattern, and/or may otherwise be adjusted (e.g., to a frequency that is at least different than the beacon frequency and that does not interfere with the beacon frequency). The wireless power transfer efficiency of system  8  may decrease as a result of modifying the coil drive signal and corresponding transmitted wireless power signal, but due to the changes in waveform and/or frequency of the wireless power signal, interference issues may be reduced sufficiently to allow wireless power transmissions to coexist with remote keyless system beacons. 
     Any one or more of the forgoing illustrative interference risk detection techniques may be used to detect interference risk and may be used in conjunction with any one or more of the illustrative interference mitigation techniques. 
     In a first implementation, interference is detected using synchronous detection and is mitigated by automatically ceasing wireless power transmission operations. 
     In a second implementation, interference is detected using synchronous detection and is mitigated by transmitting wireless power signals intermittently. 
     In a third implementation, interference is detected using synchronous detection and is mitigated by adjusting the waveform of the alternating-current drive signal used by the inverter. 
     In a fourth implementation, interference is detected using synchronous detection and is mitigated by adjusting the frequency of the alternating-current drive signal used by the inverter. 
     In a fifth implementation, interference is detected using non-synchronous detection and is mitigated by automatically ceasing wireless power transmission operations. 
     In a sixth implementation, interference is detected using non-synchronous detection and is mitigated by transmitting wireless power signals intermittently. 
     In a seventh implementation, interference is detected using non-synchronous detection and is mitigated by adjusting the waveform of the alternating-current drive signal used by the inverter. 
     In an eight implementation, interference is detected using non-synchronous detection and is mitigated by adjusting the frequency of the alternating-current drive signal used by the inverter. 
     In a ninth implementation, interference is detected using an indirect detection technique in which a wireless receiver detects key codes and is mitigated by automatically ceasing wireless power transmission operations. 
     In a tenth implementation, interference is detected using an indirect detection technique in which a wireless receiver detects key codes and is mitigated by transmitting wireless power signals intermittently. 
     In an eleventh implementation, interference is detected using an indirect detection technique in which a wireless receiver detects key codes and is mitigated by adjusting the waveform of the alternating-current drive signal used by the inverter. 
     In a twelfth implementation, interference is detected using an indirect detection technique in which a wireless receiver detects key codes and is mitigated by adjusting the frequency of the alternating-current drive signal used by the inverter. 
     In a thirteenth implementation, interference is detected using an indirect detection technique based on location monitoring and is mitigated by automatically ceasing wireless power transmission operations. 
     In a fourteenth implementation, interference is detected using an indirect detection technique based on location monitoring and is mitigated by transmitting wireless power signals intermittently. 
     In a fifteenth implementation, interference is detected using an indirect detection technique based on location monitoring and is mitigated by adjusting the waveform of the alternating-current drive signal used by the inverter. 
     In a sixteenth implementation, interference is detected using an indirect detection technique based on location monitoring and is mitigated by adjusting the frequency of the alternating-current drive signal used by the inverter. 
     In a seventeenth implementation, interference is detected using an indirect detection technique in which control circuitry monitors communications links established by a device with a vehicle and is mitigated by automatically ceasing wireless power transmission operations. 
     In a eighteenth implementation, interference is detected using an indirect detection technique in which control circuitry monitors communications links established by a device with a vehicle and is mitigated by transmitting wireless power signals intermittently. 
     In a nineteenth implementation, interference is detected using an indirect detection technique in which control circuitry monitors communications links established by a device with a vehicle and is mitigated by adjusting the waveform of the alternating-current drive signal used by the inverter. 
     In a twentieth implementation, interference is detected using an indirect detection technique in which control circuitry monitors communications links established by a device with a vehicle and is mitigated by adjusting the frequency of the alternating-current drive signal used by the inverter. 
     In a twenty-first implementation, interference is detected using an indirect detection technique in which input-output circuitry is used to determine when a device is located in a vehicle and is mitigated by automatically ceasing wireless power transmission operations. 
     In a twenty-second implementation, interference is detected using an indirect detection technique in which input-output circuitry is used to determine when a device is located in a vehicle and is mitigated by transmitting wireless power signals intermittently. 
     In a twenty-third implementation, interference is detected using an indirect detection technique in which input-output circuitry is used to determine when a device is located in a vehicle and is mitigated by adjusting the waveform of the alternating-current drive signal used by the inverter. 
     In a twenty-fourth implementation, interference is detected using an indirect detection technique in which input-output circuitry is used to determine when a device is located in a vehicle and is mitigated by adjusting the frequency of the alternating-current drive signal used by the inverter. 
     In a twenty-fifth implementation, interference is detected using synchronous detection and is mitigated by prompting a user for input and adjusting ceasing wireless power transmission operations in response to the user input. 
     In a twenty-sixth implementation, interference is detected using non-synchronous detection and is mitigated by prompting a user for input and adjusting ceasing wireless power transmission operations in response to the user input. 
     In a twenty-seventh implementation, interference is detected using indirect detection and is mitigated by prompting a user for input and adjusting ceasing wireless power transmission operations in response to the user input. 
     The foregoing describes a technology that uses data communication in the context of power transfer operations. The present disclosure contemplates that it may be desirable for power transmitter and receiver circuitry to communicate information such as states of charge, charging speeds, power transfer levels, and other wireless power transmission settings to control power transfer. The above-described technology need not involve the use of personally identifiable information in order to function. To the extent that implementations of this charging technology involve the use of personally identifiable information, implementers should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.