Abstract: Systems, methods and apparatus for wireless charging are disclosed. A wireless charging device has a plurality of charging cells provided on a first surface and a processor configured to provide a charging current to a first charging coil in a surface of the wireless charging device, determine that an impedance of a resonant circuit has varied from a threshold or setpoint impedance, and restore the threshold or setpoint impedance by modifying frequency of the charging current. The resonant circuit may include the first charging coil. A method for operating the wireless charging device includes providing a charging current to a first charging coil in a surface of the wireless charging device, determining that an impedance of a resonant circuit has varied from a threshold or setpoint impedance, and restoring the threshold or setpoint impedance by modifying frequency of the charging current. The resonant circuit may include the charging coil.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging device includes a power transmitting coil, a transformer and a driver circuit. The power transmitting coil may be configured to produce an electromagnetic flux centered on an axis that is substantially perpendicular to a plane surface of the planar magnetic core. The transformer may be located adjacent to the planar magnetic core and the driver circuit may be configured to use a stepped-up voltage received from the transformer to provide a charging current to the power transmitting coil. The transformer may include a magnetic half-core that contacts the planar magnetic core such that the planar magnetic core completes a magnetic path through the magnetic half-core.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. An apparatus has a wireless charging apparatus has a battery charging power source coupled to a charging circuit, a plurality of charging cells configured to provide a charging surface, and a controller. The controller may be configured to provide a pulse to the charging circuit, detect a frequency of oscillation of the charging circuit responsive to the pulse or a rate of decay of the oscillation of the charging circuit, and determine that a chargeable device has been placed in proximity to a coil of the charging circuit based on changes in a characteristic of the charging circuit. The pulse may have a duration that is less than half the period of a nominal resonant frequency of the charging circuit.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging device has multiple transmitting coils, a driver circuit configured to provide a charging current to the resonant circuit, and a controller. The charging cells may provide a charging surface. The driver circuit may be configured to provide a charging current to the transmitting coils. The charging device includes a radio interface configured for transmitting and receiving radio frequency identification (RFID) signals. The controller may be configured to transmit an interrogation signal configured to stimulate RFID tags through the radio interface when a chargeable device is initially placed on or near a surface of the wireless charger, refrain from initiating wireless charging of a chargeable device when a response to the interrogation signal is received, and negotiate a charging configuration when a response to the interrogation signal is not received.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. One method performed at a wireless charging device includes initiating transmission of a digital ping at a first power level a transmitting coil of the wireless charging device, increasing power level of the digital ping one or more times until current flowing to the transmitting coil has an amplitude that supports Amplitude Shift Key modulation of the digital ping, and determining a charging configuration for transferring power to a chargeable device when a response to the digital ping is received from the chargeable device.

Abstract: A charging device has a first printed circuit board (PCB) having a top metal layer and a bottom metal layer, where a first plurality of charging cells is provided on the top metal layer of the first PCB and a second plurality of charging cells is provided on the bottom metal layer of the first PCB. The charging device may have a second PCB having a top metal layer and a bottom metal layer, where a third plurality of charging cells is provided on the top metal layer of the second PCB and a fourth plurality of charging cells is provided on the bottom metal layer of the second PCB. An adhesive layer may join the first and second PCBs. One or more interconnects may be provided between the bottom metal layer of the first PCB and the top metal layer of the second PCB.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging device has a plurality of charging cells provided on a charging surface, a charging circuit and a controller. The controller may be configured to cause the charging circuit to send pings from a plurality of charging coils using an analog ping process to scan for one or more ping responses from a receiving device in proximity to the charging surface. A subset of charging coils of the plurality of charging coils that received ping responses from the receiving device in response to the sending of pings with the analog process may be determined. Subsequently, the controller then sends pings from the subset of charging coils using a digital ping process. A combination of one or more charging coils of the subset of charging coils may then be selected based on ping responses from the receiving device.

Abstract: A wireless charging device has a controller and at least one coil that is positioned near the surface of the charging device and configured to transmit an electromagnetic field and a first driver circuit configured to drive the transmitting coil. The controller is configured to cause the driver circuit to provide a charging current to the transmitting coil, decode a request for lower transmission power from a modulation of the charging current, reduce the amplitude of the charging current in accordance with the request for lower transmission power when a temperature measured at a surface of the charging device is less than a threshold temperature, and initiate a cool down sequence when the temperature measured at the surface of the charging device equals or exceeds the threshold temperature. In one example, the request for lower transmission power may be provided in an ASK-modulated signal superimposed on the charging current.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging device has a resonant circuit comprising one or more transmitting coils, a driver circuit configured to provide a charging current to the resonant circuit, a zero-crossing detector configured to provide a zero-crossing signal that includes edges corresponding to transitions of a voltage measured across the resonant circuit through a zero volt level or corresponding to transitions of a current in the resonant circuit through a zero ampere level and an Amplitude Shift Keying demodulator. The demodulator may be configured to receive a plurality of samples of voltage or current in the resonant circuit captured at times determined by the edges included in the zero-crossing signal, and demodulate a modulated signal obtained from the charging current using the plurality of samples of voltage or current in the resonant circuit.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging device has a resonant circuit that includes a transmitting coil. The charging device also has a driver circuit configured to power the resonant circuit, a pulse width modulator and a controller configured to provide a control signal to the pulse width modulator the control signal configuring the pulse width to provide a modulated drive signal to the driver circuit. The pulse width modulator is configured to provide the modulated drive signal to the resonant circuit. The resonant circuit is configured to operate as a low-pass filter that blocks frequency components of the modulated drive signal that correspond to the reference signal. The driver circuit is configured to use the modulated drive signal to produce a charging current in the resonant circuit. The charging current causes power to be wirelessly transferred to a receiving device through the transmitting coil.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging apparatus has an amplifier stage, a power switching stage and a controller. The amplifier stage has a choke that receives a current from an input of the amplifier stage, a resonant network coupled to an output of the choke and that provides an output current to a load, and a first switch configured to short the output of the choke to circuit ground when turned on. The power switching stage may be configured to couple a power supply to the input of the amplifier stage and may have a second switch operable to couple the input of the amplifier stage to circuit ground when turned on. The controller may be configured to control operation of the first switch and the second switch in accordance with a timing sequence that defines a cycle of the output current.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging device has a plurality of charging cells provided on a charging surface, a charging circuit and a controller. The controller may be configured detect the presence of a foreign object in proximity to at least one charging coil of a plurality of charging coils in the charging device that is selected for supplying charging energy to a receiving device. Additionally, the controller may be configured to determine whether one or more other charging coils is capable of supplying charging energy to the receiving device, and determine, for each of the one or more other charging coils, whether the foreign object is in proximity thereto. Further, the controller may be configured to select at least one of the one or more other charging coils not in proximity to the foreign object for supplying charging energy to the receiving device.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. An apparatus includes or operates as a wireless charging device that has a battery charging power source coupled to a charging circuit, a plurality of charging cells provided on a surface of the wireless charging device and a controller or processing circuit, which may include one or more processors. The apparatus has a high-pass filter configured to extract high-frequency components from a measurement signal representative of voltage at a transmitting coil during a charging operation, a first attenuator configured to attenuate the measurement signal and provide an attenuated measurement signal, a mixer configured to add a signal representative of the high-frequency components to the attenuated measurement signal to obtain a scaled measurement signal, and a demodulator configured to decode one or more messages associated with the charging operation from the scaled measurement signal.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A wireless charging device has a plurality of charging cells provided on a first surface and a processor configured to provide a charging current to a first charging coil in a surface of the wireless charging device, determine that an impedance of a resonant circuit has varied from a threshold or setpoint impedance, and restore the threshold or setpoint impedance by modifying frequency of the charging current. The resonant circuit may include the first charging coil. A method for operating the wireless charging device includes providing a charging current to a first charging coil in a surface of the wireless charging device, determining that an impedance of a resonant circuit has varied from a threshold or setpoint impedance, and restoring the threshold or setpoint impedance by modifying frequency of the charging current. The resonant circuit may include the charging coil.

Abstract: Systems, methods and apparatus for providing a wireless charging device are disclosed. A method for operating the wireless charging device includes transmitting a first pulse through each of a plurality of charging circuits, determining peak voltage at nodes in the plurality of charging circuits, each node coupling a transmitting coil to a capacitor in one charging circuit in the plurality of charging circuits, the peak voltage at each node being responsive to the first pulse and indicative of a coupling coefficient with a receiving coil in a chargeable device, determining that a minimum peak voltage responsive to the first pulse is associated with a first charging circuit in the plurality of charging circuits, and providing a first charging current to the first charging circuit.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A test apparatus has a receiving head configured to provide a measurement signal representative of electromagnetic flux received from one or more transmitting coils of a wireless charging surface, a numerically-controlled stage configured to position the receiving head at a selected point in three-dimensional space above wireless charging surface, and a processor configured to cause the numerically-controlled stage to position the receiving head at the selected point in three-dimensional space, and use the measurement signal to determine magnitude of the electromagnetic flux or power received from the wireless charging surface proximate to the selected point in three-dimensional space.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. One method includes providing a first charging current to a first transmitting coil in a wireless charging device, where the first transmitting coil is coupled to a receiving coil in a first power receiving device, providing a second charging current to a second transmitting coil in the wireless charging device, where the second transmitting coil is coupled to a receiving coil in a second power receiving device, the first charging current and the second charging current being provided at different frequencies from one another, receiving a first modulated signal from the first power receiving device, where the first modulated signal includes a carrier signal provided at a frequency corresponding to the frequency of the first charging current, and filtering the first modulated signal using a band-pass filter configured to block a second modulated signal transmitted by the second power receiving device.

Abstract: A wireless charging system is configured to charge one or more receiver devices simultaneously. The wireless charging system includes multiple coils that may be driven independently based on a feedback system with one or more feedback channels. Each coil is driven by a coil driving signal selected based on a set of target characteristics. A coil drive circuit receives an input of a pulse width modulation (PWM) signal and outputs the coil driving signal to a corresponding coil.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging device has a plurality of charging cells provided on a charging surface, a charging circuit and a controller. The controller may be configured to cause the charging circuit to provide a charging current to a resonant circuit when a receiving device is placed on the charging surface, provide a measurement slot by causing the charging circuit to decrease or terminate the charging current for a period of time and determine whether the receiving device has been removed from the charging surface based on measurement of a characteristic of the resonant circuit during the measurement slot. The characteristic of the resonant circuit may be representative of electromagnetic coupling between a transmitting coil in the resonant circuit and a receiving coil in the receiving device.

Abstract: A charging device has a first printed circuit board (PCB) having a top metal layer and a bottom metal layer, where a first plurality of charging cells is provided on the top metal layer of the first PCB and a second plurality of charging cells is provided on the bottom metal layer of the first PCB. The charging device may have a second PCB having a top metal layer and a bottom metal layer, where a third plurality of charging cells is provided on the top metal layer of the second PCB and a fourth plurality of charging cells is provided on the bottom metal layer of the second PCB. An adhesive layer may join the first and second PCBs. One or more interconnects may be provided between the bottom metal layer of the first PCB and the top metal layer of the second PCB.