Abstract: A RF wireless charging enclosure configured to enable efficient wireless charging of a CE device in the enclosure while also allowing wireless communication of the CE device to devices outside the enclosure. In one example, time multiplexing is used such that the CE device is enabled to either be charged, or to communicate with a device outside the enclosure. In another example, frequency division is used such that the CE device is charged at a first frequency, and simultaneously communicates through the enclosure at a second different frequency.

Abstract: A coil module and a wireless power transmitting circuit using the same are disclosed. At least three sets of coils are configured to be connected in series and overlapped each other, which may, in one hand, increase the coupling coefficient between the power transmitting coil and the power receiving coil, and in the other hand, make the alternating magnetic field generated by the coil module more concentrated so as to reduce negative influences caused by the strayed magnetic field around the coil module.

Abstract: A liquid dispenser may include a tank having a bottom plate, an inner assembly detachably coupled to the tank and containing a pump, and a docking station provided below the bottom plate that receives external power. A wireless power receiver may be provided above the bottom plate and may be electrically connected to a wireless power transmitter provided below the bottom plate. A supply plate may coupled to a supply pipe that supplies liquid pumped from the pump, and liquid falling from the supply plate may be guided back to the tank via a liquid guide. The docking station may apply external power to the pump via the wireless power transmitter and receiver.

Abstract: A vehicle storage structure includes a center console, an instrument panel, and a storage having an opening. The center console includes a front part. The storage is located at least one of the front part, a portion in front of the center console, or the instrument panel. The storage includes a first storage and a second storage. The first storage is located lower or higher than the second storage. The first storage includes a side wall and a first opening. The side wall is located proximate to a passenger seat in a vehicle width direction. The first opening is located proximate to a driver's seat in the vehicle width direction.

Abstract: The invention includes a memory unit that stores electrical characteristics of a power receiving coil of an electric lawnmower and a power transfer coil of an external charger, wherein a battery side control circuit performs a test power transfer from a power transferring/receiving coil to the power receiving coil or the power transfer coil to obtain electrical characteristics of a power receiving side, compares the electrical characteristics to the electrical characteristics stored in the memory unit to determine whether the electrical characteristics are of a power transfer to the power receiving coil or of a power transfer to the power transfer coil, and performs control to switch to a power transfer mode with respect to the power receiving coil or to a power receiving mode with respect to the power transfer coil.

Abstract: Implementations relate to configuration of wireless communication signals between devices. In some implementations, a method includes determining a transmission scenario associated with transmission of wireless signals of a particular wireless communication protocol from a first device to a second device. The transmission scenario specifies one or more transmission characteristics for the signal transmission. A test message is sent wirelessly from the first device to the second device according to the transmission scenario, and a reply message is received from the second device in response to test message. The reply message includes one or more signal quality indicators that indicate a signal quality of the test message. The transmission scenario is selected as a designated scenario based on the signal quality indicators, and data is wirelessly transmitted from the first device to the second device according to the designated scenario.

Abstract: The present disclosure relates to a method for providing compatibility with a wireless power transmitting device in a wireless power transmitting system. The method includes the steps of: detecting a wireless power receiving device on the basis of a load change; transmitting a request signal for requesting information for a receiving device to the wireless power receiving device; receiving the information for the receiving device from the wireless power receiving device, wherein the information selectively includes version information on standard technical specifications for realizing the wireless power receiving device; and, when the version information is included in the information for the receiving device, performing a wireless power transmitting operation according to the standard technical specifications corresponding to the version information.

Abstract: A battery system, a control method of a cell balance procedure and a calculation method of a balance charge capacity are provided. The battery system includes a plurality of battery units, a communication bus and a host control unit. Each battery unit includes a plurality of cells, an isolated charger, a switch array circuit, a balance slave switch and a balance slave controller. The host control unit includes a balance host controller, a balance host switch and a system current measurement unit. When the error between a balance detection voltage calculated by each balance slave controller and the balance detection voltage calculated by the balance host controller is less than a predetermined value, the balance host switch and the corresponding balance slave switches are in conduction and the specified plurality cells of battery system are charged for keeping cell balance purpose.

Abstract: A wireless charging method can be applied to a wireless charging device and include: acquiring a charging parameter of a target electronic device, in which the charging parameter includes a current temperature parameter of the target electronic device; and dynamically adjusting a magnetic levitation distance between the wireless charging device and the target electronic device according to the temperature parameter.

Abstract: A charge system for a vehicle includes a traction battery and a controller. The controller, responsive to passage of a predetermined period of time following activation of the vehicle without detecting a wake up signal, sets a diagnostic flag. The controller further, responsive to deactivation of the vehicle, presence of the diagnostic flag, and presence of a request designating a future start time for a charge event of the traction battery, initiates the charge event regardless of the future start time. The controller may further, responsive to deactivation of the vehicle, absence of the diagnostic flag, and presence of the request designating the future start time for the charge event of the traction battery, inhibit start of the charge event until the future start time.

Abstract: A method of operating a portable power station including a plurality of battery modules and a battery management system operably connected to the plurality of battery modules, includes supplying at least one first battery module of the plurality of battery modules with a charging current generated from mains electricity operably connected to an AC input connection of the portable power station using the battery management system, and electrically connecting at least one second battery module of the plurality of battery modules to a load to supply the load with an operating current using the battery management system. The method further includes electrically disconnecting at least one third battery module of the plurality of battery modules from the charging current and the load to manage thermally the at least one third battery module using the battery management system.

Abstract: The invention relates to a battery-powered device, comprising a first controller, a first battery interface, and at least one electric consumer, wherein the first battery interface is configured to receive at least one configurable rechargeable battery pack for supplying energy to the at least one electric consumer; and wherein the first controller is embodied to receive at least one battery charging parameter at the first battery interface, and to reconfigure the at least one battery charging parameter by means of the first battery interface according to the power demands of the at least one electric consumer or according to a given user-specification.

Abstract: An electronic device included a first energy storage device coupled to a second energy storage device by a conductor. A charging node is coupled to the first energy storage device. Another conductor couples the charging node to the second energy storage device. A switch is electrically coupled between the conductor and the second energy storage device. A control circuit opens the switch, thereby allowing a first charging current to flow from the charging node to the first energy storage device through the conductor and a second charging current to flow from the charging node to the second energy storage device through the other conductor and closes the switch when a difference between a voltage of the first energy storage device and a voltage of the second energy storage device is within a predefined voltage difference threshold.

Abstract: A device for high-frequency communication and for the inductive charging of an apparatus, including a charging surface, at least one charging antenna emitting a magnetic field at a low frequency and a layer of ferromagnetic material. The device includes at least one communication antenna and a printed circuit board. The communication antenna is in the form of a coil locally surrounding the layer with an axis of symmetry located in a plane parallel to the layer. The material of the layer is selected so as to have, at high frequency, an imaginary part with sufficiently high permeability to generate leaks on a surface of the layer extending perpendicular to the layer, while at the same time maintaining, at low frequency, an imaginary part with sufficiently low permeability to allow inductive charging.

Abstract: A non-contact power transmission apparatus accurately determines the kind of object that is placed on the charging deck of the non-contact power transmission apparatus, and, only when a non-contact power receiving apparatus is placed on the power transmission apparatus, allows power transmission and data communication to take place, thereby accurately determining the state of the receiver side and efficiently controlling the transmission of power. In the power transmission apparatus, the power supplied to the non-contact power receiving apparatus is measured, and the output power of the wireless power signal output from two different cores is controlled, thereby allowing the charging operation to be stably conducted even if the non-contact power receiving apparatus is moved anywhere on the power transmission apparatus.

Abstract: A power transmitter for wireless power transfer includes a control and communications unit, an inverter circuit, at least one coil, a shielding, a housing, and a removable front plate. The housing is configured to house, at least in part, one or more of the control and communications unit, the invertor circuit, the at least one coil, the shielding, or combinations thereof. The removable front plate is configured to mechanically connect to the housing, the removable front plate including at least one magnet, the at least one magnet configured to attract a receiver magnet when a power receiver is proximate to the removable front plate.

Abstract: The smart wearable with embedded NFC (Near Field Communication) tags, vital health sensors and UV-C germicidal irradiation sources is provided for Prevention of spread of pathogens. The smart wearables is any of a hand glove, a footwear, a vest, a full body suit, a face mask, a footwear cover or a smart portables where all the smart wearables includes a plurality of re-programmable tags to facilitate touch less activities, and a plurality of body health monitoring sensors to monitor health of the wearer in real time for early warning health mechanisms, an Ultraviolet Germicidal Irradiation (UVGI) source to disinfect the surfaces coming in contact with the smart wearables with maximum efficacy and spread prevention. Further, the inner layer of the smart wearables which makes contact with the skin of the wearer is made of a Celliant synthetic polymer fabric material that traps the body's infrared energy and cycle it back to improve oxygenation and resolve minor aches and pains.

Abstract: Embodiments of the present disclosure describe techniques for encoding beacon signals in wireless power delivery environments. More specifically, techniques are disclosed for encoding beacon signals to isolate client devices for wireless power delivery in wireless power delivery environments. The beacon signals can be encoded or modulated with a transmission code that is provided to selected clients in the wireless power delivery environment. In this manner, beacon signals from the select clients can be identified and the corresponding client devices isolated for wireless power delivery.

Abstract: An adapter device is configured to interface between a wireless power receiver that includes a first array of magnets arranged around a receiver coil in the wireless power receiver and a wireless power transmitter lacking a corresponding array of magnets arranged around a source coil in the wireless power transmitter. The adapter device includes a substrate and a ferrite shield formed of a magnetic material and configured to be placed between the wireless power receiver and the wireless power transmitter.

Abstract: A power transmitter for wireless power transfer includes a control and communications unit, a vehicular power input regulator, an inverter circuit, at least one coil, a shielding, a housing, and a removable front plate. The housing is configured to house, at least in part, one or more of the control and communications unit, the invertor circuit, the at least one coil, the shielding, or combinations thereof. The removable front plate is configured to mechanically connect to the housing, the removable front plate including at least one magnet, the at least one magnet configured to attract a receiver magnet when a power receiver is proximate to the removable front plate.

Abstract: The present invention relates to a wireless power transmission method and apparatus therefor. A wireless power transmitter according to an embodiment may comprise: a plurality of transmission coils; an alternating current power generator for generating a plurality of alternating current power signals applied to the plurality of transmission coils; a power source for supplying direct current power to the alternating current power generator; and a controller for controlling the phases of the plurality of alternating current power signals, wherein the controller changes the phase of at least one of the plurality of alternating current power signals to control transmission power output through the plurality of transmission coils. Therefore, the present invention provides an advantage in that a wireless power transmitter including a plurality of transmission coils can more precisely control wireless power.

Abstract: A power transmission device for a noncontact power supply device includes a resonant circuit that outputs an alternating magnetic flux by power from a power source circuit, and switching elements for making the resonant circuit generate an alternating magnetic flux, and transmits power to a power receiving coil of a power reception device by the alternating magnetic flux. A power transmission controller of the power transmission device includes a transmission mode of supplying alternating power to the resonant circuit by repeating ON and OFF of switching elements by controlling switching elements. ON time in one cycle of operation of each of switching elements used in the transmission mode is a first fixed value. Accordingly, the power transmission device in a simplified configuration can be provided.

Abstract: The invention: determines if the duration of the conducting state of the semiconductors in a first cycle of the pulse width modulation is upper than a predetermined duration, measures, during the conducting state of the semiconductors at a second cycle, the voltage provided to the load, sequentially disables the conduction of each semiconductor during a part of the duration of the conducting state of the semiconductors in a third cycle and measures the voltage provided to the load, determines the differences between the voltage measured during the second cycle and each voltage measured during the third cycle, orders the differences according to their value, checks if the determined order is identical to an order stored in a memory of the device and determines that one connection of one semiconductor is deteriorated if the order is changed.

Abstract: A method and system for operating a power circuit capable of transmitting and receiving wireless power. The method includes determining that the power circuit is operating in receive mode, and, based thereon, having a first equivalent capacitance. The method further includes determining that the power circuit is operating in the transmit mode, and, based thereon, having a second equivalent capacitance. The first equivalent capacitance being different than the second equivalent capacitance.

Abstract: A wireless power transmitter configured to transfer power to a wireless power receiver, including a coil assembly comprising first and second bottom coils placed adjacent to each other in a line and each consisting of a single layer of 11 turns and a top coil stacked on the first and second bottom coils and consisting of a single layer of 12 turns; and a full-bridge inverter.

Abstract: A system and method for inductively providing electrical power at a plurality of power levels to electrical devices. The system may include an inductive power outlet unit conductively coupled to a power supply and an inductive power receiver unit associated with the electrical device. The inductive power outlet unit includes a driver device operable to generate power at a plurality of power levels and electrical power is transferred to the electrical device at a power level selected from the plurality of power levels, in accordance with electrical power requirements of the electrical device. The power receiver may be operable in a plurality of modes having a secondary inductor configured to operate selectively with a plurality of inductance values.

Abstract: An unobtrusive augmented reality (AR) system can be used to assist the wearer in every day interactions by projecting information from the contact lens display onto the retina of the wearer's eye. The unobtrusive augmented reality system includes a necklace and a contact lens display that are unobtrusive to the wearer and the wearer's surrounding environment. The necklace of the unobtrusive augmented reality system generates power and data for the contact lens displays. The necklace and contact lens display include conductive coils inductively coupled by a magnetic field. The inductive coupling allows data and power generated by the necklace to be transferred to the contact lens display. A projector in the contact lens display projects images generated from the data onto the retina of the wearers eye.

Abstract: A system and method for inductively providing electrical power at a plurality of power levels to electrical devices. The system may include an inductive power outlet unit conductively coupled to a power supply and an inductive power receiver unit associated with the electrical device. The inductive power outlet unit includes a driver device operable to generate power at a plurality of power levels and electrical power is transferred to the electrical device at a power level selected from the plurality of power levels, in accordance with electrical power requirements of the electrical device. The power receiver may be operable in a plurality of modes having a secondary inductor configured to operate selectively with a plurality of inductance values.

Abstract: An electric power charge and discharge system for an electronic device having a battery, by which the electronic device can be used for a long period of time. In a wireless communication device including a wireless driving portion including a first battery and a wireless charging portion including a second battery, the first battery is charged by electric power from a fixed power supply and the second battery is charged by using electromagnetic waves existing in an external space. Further, the first battery and the second battery are discharged alternately, and during a period in which the first battery is discharged, the second battery is charged.

Abstract: An apparatus for multi-pad wireless charging is disclosed. The apparatus includes a plurality of primary pad apparatuses. Each primary pad apparatus is positioned to transmit power to a secondary pad apparatus of a vehicle. The primary transmitter pad apparatuses are spaced apart sufficient for each of a plurality of vehicles to be positioned over one primary pad apparatus of the plurality of primary pad apparatuses. The apparatus includes a power converter apparatus connected to each of the plurality of primary pad apparatuses, a power feed that provides power to the power converter apparatus and a sharing controller that selectively controls which of the plurality of primary pad apparatuses transmits power to a secondary pad apparatus and/or controls power sharing between the primary pad apparatuses.

Abstract: A wireless power-feeding apparatus that enables efficient wireless feeding to a power-receiving coil embedded at the center of a spherical power-receiving device. The apparatus includes: a holding member for holding the power-receiving device; a power-transmitting coil; a driver circuit for supplying the power-transmitting coil with high-frequency current to generate a magnetic flux for wireless power-feeding to the power-receiving coil; and a wireless data receiver for receiving data transmitted regularly from a wireless data transmitter, the power-transmitting coil being positioned relative to the holding member in such a manner that the axes of the power-receiving coil and the power-transmitting coil are parallel to each other when the power-receiving device is held by the holding member in such a manner that a mark provided on the surface of the power-receiving device faces a predetermined direction.

Abstract: Methods and apparatuses for in-use charging for wearable devices are described, in which the wearable device may include an energy harvesting unit coupled with a rechargeable battery unit. The energy harvesting unit may include one or more transducers configured to generate electrical energy from various types of non-electrical energy around the wearable device such that the wearable device may replenish the rechargeable battery unit while a person uses the wearable devices. Such non-electrical energy may include electromagnetic energy, light energy, thermal energy, kinetic energy, or the like. Additionally, the rechargeable battery unit may include two or more partitions such that one of the partitions may be detached when necessary (e.g., to replace with a fully charged partition) without disrupting operations of the wearable device.

Abstract: Systems and methods for leveraging multipath wireless transmissions for charging devices within multipath signaling environment. Techniques according to the present technology include determining a received signal strength of a radio frequency signal received via a plurality of paths at two or more antennas of a plurality of antennas of an antenna array. The techniques also include configuring parameters for transmission of a wireless power signal over one or more paths of the plurality of paths for which the received signal strength exceeds a threshold value. The techniques further include directing at least a portion of the plurality of antennas to transmit the wireless power signal over the one or more paths according to the parameters. Resulting signal transmissions may thus be directionally biased toward least lossy pathways between a wireless power transmitter and a device in need of receiving wireless power.

Abstract: An electric device provided by the disclosure includes: a battery; at least two charging circuits respectively connected with the battery; a charging port, connected with the at least two charging circuits; and at least two wireless receiving circuits, connected with the at least two charging circuits by one-to-one correspondence; wherein the at least two charging circuits are configured for processing a voltage and a current output by the charging port or each wireless receiving circuits, and providing the processed voltage and current to charge the battery. The electric device charges the battery by using multiple charging circuits, which may improve the charging power of the battery and accelerate the charging rate.

Abstract: A wireless charging device includes a driver unit configured to generate one of a first AC voltage signal having a first frequency and a second AC voltage signal having a second frequency. Also, the wireless charging device includes a transmitting unit having a first coil and a first capacitor and configured to transmit the first AC voltage signal. Further, the transmitting unit includes a second coil and a second capacitor and configured to transmit the second AC voltage signal. Additionally, the wireless charging device includes a control unit configured to detect a first receiver device operating at the first frequency based on a change in a first voltage in the transmitting unit, and detect a second receiver device operating at the second frequency based on a change in a second voltage in the transmitting unit.

Abstract: The present disclosure provides a mobile terminal, a charging device and a charging method thereof. A first communication module is disposed in the mobile terminal and a second communication module is disposed in the charging device to perform match verification. After the match verification is successful, the mobile terminal may transmit a charging request including a charging parameter required by the mobile terminal to the charging device, and then receive first energy that matches the charging parameter and is transmitted by the charging device. After the mobile terminal converts the first energy into a direct current voltage for charging, the mobile terminal can directly use the direct current voltage corresponding to the first energy for charging.

Abstract: A wireless power system has a wireless power transmitting device and a wireless power receiving device. The wireless power transmitting device may be a wireless charging mat or other device with one or more wireless power transmitting coils for transmitting wireless power signals. The wireless power receiving device may be a portable electronic device with one or more wireless power receiving coils for receiving the transmitted wireless power signals. The wireless power transmitting device may have foreign object detection coils. Q-factor measurements may be made on the transmitting coil during wireless power transmission and/or voltage measurements may be made using the foreign object detection coils to detect whether a foreign object is present. The foreign object detection coils may include overlapping coils with different winding patterns to enhance foreign object detection coverage.

Abstract: A robot for charging a vehicle is provided. The robot has wheels or configured for a track for the robot to automatically move to the vehicle to provide charge to a battery of the vehicle. A charge storage is associated with the robot. An articulating arm of the robot. The articulating arm is configured for movement that enables the articulating arm to automatically connect to a connector of the vehicle after the robot moves in position beside the vehicle for providing charge to the battery of the vehicle.

Abstract: A wireless charging unit to be attached to a back surface of a side wall of a case in which an electronic device including internally a wireless power receiving coil is placed upright. The wireless charging unit includes a power supplying coil provided at a position facing the back surface of the side wall of the case to wirelessly supply power, circuit board connected to the power supplying coil to feed a current to the power supplying coil, and a housing that houses the circuit board. The center of the power supplying coil is located above the center of the housing in an in-plane direction of the power supplying coil.

Abstract: A non-contact power reception apparatus is provided, in which a power reception coil for a charging system and a loop antenna for an electronic settlement system are mounted on a battery pack and a cover case of a portable terminal such that the power reception coil is arranged in the center thereof and the loop antenna is disposed outside the power reception coil, so that a mode of receiving a wireless power signal and a mode of transmitting and receiving data are selectively performed, thereby preventing interference from harmonic components and enabling non-contact charging and electronic settlement using a single portable terminal. A jig for fabricating a core to be mounted to the non-contact power reception apparatus is provided.

Abstract: A passive radio frequency identification (RFID) tag includes: a rectifier circuit that rectifies a signal obtained from an antenna and outputs the rectified signal as a DC voltage. A capacitor is connected to an output line of the rectifier circuit. A first regulator circuit generates a first regulator voltage by stabilizing the output DC voltage from the rectifier circuit. A control circuit starts operating when the first regulator voltage is applied, and the control circuit generates a control signal upon receipt of the modulation signal section of the wireless signal. A second regulator circuit generates a second regulator voltage by stabilizing the output DC voltage from the rectifier circuit in response to the control signal and outputs the second regulator voltage to the outside.

Abstract: A system includes a primary coil, a first drive circuit, a first sense circuit, and a communication and control circuit for providing power inductively to a portable device that includes a battery and an inductive receiver unit including a receiver coil and a receiver circuit. A portable device includes a battery and a receiver unit capable of receiving inductive power from a compatible inductive charging system including a base unit with a primary coil and associated circuit. A system includes a system rechargeable battery, an inductive coil, a drive circuit, a sense circuit, a communication and control circuit, a receiver rectifier circuit, and a wired power input for providing power inductively to a compatible portable device comprising a battery and an inductive receiver unit including a receiver coil and a receiver circuit.

Abstract: A wireless charger, comprising: a thermal-conductive plastic cover; a first circuit board; and a metallic case, wherein the first circuit board are disposed in the metallic case, wherein a wind tunnel is formed between the thermal-conductive plastic cover and the circuit board for lowering the temperature of an electronic device that is wirelessly charged on the thermal-conductive plastic cover.

Abstract: An information handling system with a wireless charging device may include a processor; a memory; a power management unit (PMU); an antenna controller to provide instructions to a radio to cause an antenna to transceive wirelessly with a network; a wireless charging scheduling controller configured to: receive transmission scheduling data from the antenna controller descriptive of when the radio is transmitting and receiving data to and from the network; and initiate, at a charging coil of the wireless charging device, a charging procedure to wirelessly charge a power storage device when the transmission scheduling data indicates that the radio is receiving data from the network or is idle.

Abstract: An electric vehicle (EV) charging system includes a number of output connections (e.g., cables). Each of the output connections is connected to at least one head, and each head can be connected concurrently to an EV. A controller can direct a charging current, delivered over a dedicated circuit from an electric power supply, to a first one of the output connections if a first EV is connected to a head connected to the first one of the output connections. Then, the charging current to the first one of the output connections can be stopped, switched to a second one of the output connections, and restarted if a second EV is connected to a head connected to the second one of the output connections.

Abstract: A wireless charging holder for vehicles, which is used to firmly clamp a mobile terminal and wirelessly charge the mobile terminal, comprises a fixing component, a supporting component, a steering joint and a conductive circuit. The fixing component is for fixing a mobile terminal and includes a wireless charging module for charging the mobile terminal. The supporting component is for supporting the fixing component. The steering joint is connected between the fixing component and the supporting component, thereby the fixing component may rotate relative to the supporting component. The conductive circuit is extending from an inside of the supporting component through an inside of the steering joint and into an inside of the fixing component, to connect with the wireless charging module.

Abstract: A Near-Field Communication (NFC) antenna structure includes an NFC antenna and a conductive structure. The NFC antenna extends to form an inner coil and an outer coil. The conductive structure is formed corresponding to a region between the inner coil and the outer coil.

Abstract: Aspects relate to a charging station configured to transfer power between an electric aircraft and a power grid via a charging connection. In one or more embodiments, charging station may communicate with the power grid and/or electric aircraft via a communication network. For example, the charging station may be configured to receive a supply request from a power grid or a demand request from an electric aircraft and subsequently generate a control signal that transfers electrical power between the power grid and the electric aircraft via the charging connection.

Abstract: A method and a system are provided for updating settings of a wireless device. An inductive coupling link is established between a first wireless device and a second wireless device upon detection that the first wireless device is within a threshold proximity to the second wireless device. The second wireless device receives a token from the first wireless device via the inductive coupling link. The second wireless device forwards the token to a remote device that stores a user profile associated with the user of the first wireless device. The second wireless device receives at least a portion of the user profile from the remote device in response to the token being forwarded. The second wireless device performs an update procedure to update one or more settings of the second wireless device in accordance with the received at least the portion of the user profile.

Abstract: A wireless charging device includes a driver unit configured to generate one of a first AC voltage signal having a first frequency and a second AC voltage signal having a second frequency. Also, the wireless charging device includes a transmitting unit having a first coil and a first capacitor and configured to transmit the first AC voltage signal. Further, the transmitting unit includes a second coil and a second capacitor and configured to transmit the second AC voltage signal. Additionally, the wireless charging device includes a control unit configured to detect a first receiver device operating at the first frequency based on a change in a first voltage in the transmitting unit, and detect a second receiver device operating at the second frequency based on a change in a second voltage in the transmitting unit.