Abstract: A uniform magnetic field may provide better performance in wireless power transmitters due to smaller impedance variations in an output of a power amplifier of a wireless power transmitter and also allow for wireless power transmitter pads to be thinner. One aspect of the disclosure provides a device for wireless power transfer. The device comprises a substantially planar transmit antenna that is configured to generate a magnetic field. The device also comprises a pad having a charging surface. At least a portion of the transmit antenna is disposed in the pad. The device also comprises a ferromagnetic material having a shape and a position relative to the transmit antenna. At least one of the shape or position of the ferromagnetic material, or a combination thereof, is selected to modify a distribution of the magnetic field at the charging surface.

Abstract: Embodiments of the invention relate to a method and system for transferring power wirelessly to electronic devices. The system can utilize magnetic coupling between two coils at close proximity to transfer sufficient power to charge an electronic device. Embodiments of the invention pertain to an array of spiral coils that can be used to transmit power for transfer to receiver coils. Potential applications of this technology include charging consumer electronic devices (cell phones, laptops, PDAs, etc), developing hermetically sealed devices for extreme environments, and less invasive transcutaneous energy transfer (TET) systems. Various embodiments of the subject system can be referred to as PowerPad system. Embodiments can incorporate one or more of the following: planar inductors, PCB transformers, and very high frequency power supplies.

Abstract: Systems and methods for feedback control of output power in a wireless power transmitter are disclosed. According to one aspect, one of a voltage level at an input of a wireless power transmit coil and a level of current passing through the wireless power transmit coil are sensed. The wireless power transmitter includes a controller configured to adjust an electrical characteristic of the wireless power transmitter to maintain at least one of the level of current and the voltage level at a constant level.

Abstract: Systems, methods, and apparatus for amplifying a voltage in wireless power transmitters are disclosed. In one aspect, the transmitter comprises a first circuit configured to generate a first signal. The first signal comprises a non-inverted output. The transmitter further comprises a second circuit configured to generate a second signal in phase with the first signal. The second signal comprises an inverted output with respect to the non-inverted output. The first circuit and the second circuit are further configured to drive a load.

Abstract: A wireless power transmitter may generate a magnetic field via a transmit antenna to induce voltage in a receive antenna of a wireless power receiver to power the unit and/or charge the receiver's battery. An apparatus for measuring wireless power transfer at an operating frequency between the transmitter and the receiver is provided. The apparatus comprises a first clock configured to generate a first clock signal at a first clock frequency that is higher than the operating frequency of the wireless power transfer. The apparatus further comprises a controller configured to operate based on a second clock signal, the first clock frequency higher than a second clock frequency of the second clock signal. The controller is further configured to measure an amount of wireless power transfer based on the first clock signal.

Abstract: This disclosure provides systems, methods and apparatus for detecting wireless charging transmit characteristics. One aspect of the disclosure provides a method of detecting a transmit characteristic in a wireless power transmission device. The device includes a series element electrically coupled to a transmit coil. The method includes determining real and imaginary components of a first voltage at a first terminal of the series element. The method further includes determining real and imaginary components of a second voltage at a second terminal of the series element. The method further includes determining real and imaginary components of a current through the series element, based on the determined first and second voltages. The method further includes determining transmit characteristics such as nodal voltages, currents, power and impedances based on determined voltages and currents.

Abstract: Systems and methods for alignment and calibration of a wireless power transmitter and a wireless power receiver are disclosed. According to one aspect, a wireless power transmit coil is first aligned with a wireless power receive coil. An alignment signal is received indicated that the transmit coil and the receive coil are aligned is received by the wireless power transmitter. A signal indicative of a characteristic of an electrical signal received by the wireless power receiver is generated and communicated to the wireless power transmitter. A calibration feedback signal is generated to adjust a driving signal of the wireless power transmitter based on the received signal.

Abstract: Embodiments of the invention relate to a method and system for transferring power wirelessly to electronic devices. The system can utilize magnetic coupling between two coils at close proximity to transfer sufficient power to charge an electronic device. Embodiments of the invention pertain to an array of spiral coils that can be used to transmit power for transfer to receiver coils. Potential applications of this technology include charging consumer electronic devices (cell phones, laptops, PDAs, etc), developing hermetically sealed devices for extreme environments, and less invasive transcutaneous energy transfer (TET) systems. Various embodiments of the subject system can be referred to as PowerPad system. Embodiments can incorporate one or more of the following: planar inductors, PCB transformers, and very high frequency power supplies.

Abstract: Systems, methods, and apparatus for overvoltage protection in a wireless power receiver are disclosed. One aspect of the disclosure is a wireless power receiver apparatus. The apparatus includes an antenna circuit configured to wirelessly receive power, from a transmitter, at a level sufficient to power or charge a load, wherein the antenna circuit is electrically connected to an overvoltage protection circuit that is electrically connected between the antenna circuit and the load. The apparatus also includes a matching circuit electrically connected to the antenna circuit and a switching element electrically connected to the matching circuit. At least one of the matching circuit or the switching element is configured to control an amount of the received power flowing into the overvoltage protection circuit.

Abstract: Systems and methods for feedback control of output power in a wireless power transmitter are disclosed. According to one aspect, one of a voltage level at an input of a wireless power transmit coil and a level of current passing through the wireless power transmit coil are sensed. The wireless power transmitter includes a controller configured to adjust a component of the wireless power transmitter to maintain at least one of the level of current and the voltage level at a constant level.

Abstract: This disclosure provides systems, methods and apparatus for detecting an impedance of a wireless power transmitter load. In one aspect, a method of determining a reactive condition of a wireless power transmitter apparatus is provided. The method comprises determining a value correlated to a voltage of a drain of a switching element of a driver circuit of the wireless power transmitter. The method further comprises determining a reactance load change based on the determined voltage.

Abstract: Systems, devices, and methods for adjusting characteristics of a touch sensing device in the presence of a wireless power field are disclosed. According to one aspect, the presence of a wireless power field may be detected, and a characteristic of a touch sensing device may be adjusted to reduce interference of the wireless power field with the touch sensing device.

Abstract: An apparatus and method for lost power detection are described. In one implementation, an apparatus for wireless transferring power comprises a wireless power transmitter configured to wirelessly transmit power at a power level sufficient to power or charge a chargeable device. The apparatus further comprises a controller configured to determine a first and second power difference between a first and second power measurement and the second and a third power measurement of the power level provided by the wireless power transmitter at a first, second, and third sample time, respectively. The controller is further configured to determine a transmitter power difference between the first power difference and the second power difference. The controller is further configured to determine an absence or a presence of an object that affects consumption of power transmitted by the wireless power transmitter based at least on the transmitter power difference ?_T.

Abstract: Systems, methods and apparatus are disclosed for detecting power losses due to induction heating in wireless power receivers. In one aspect, an apparatus for wireless power transfer comprises a power transfer component configured to transmit wireless power to a wireless power receiver at a power level sufficient to charge or power a load. The apparatus further comprises a communications receiver configured to receive a message from the wireless power receiver, the message comprising a group identifier. The apparatus further comprises a controller circuit operationally coupled to the power transfer component and the communications receiver and configured to determine a power loss value based on the group identifier, the power loss value indicative of power loss due to induction heating presented by one or more wireless power receivers that are members of a group associated with the group identifier.

Abstract: An apparatus and method for lost power detection are described. In one implementation, an apparatus for wirelessly transferring power comprises a wireless power transmitter configured to wirelessly transmit power at a first power level sufficient to power or charge a chargeable device. The apparatus further comprises a controller configured to obtain a first power measurement of the first power level. The controller is further configured to determine a first adjusted power measurement of the first power measurement based on one or more tolerance values of the wireless power transmitter. The controller is further configured to determine a second adjusted power measurement of a second power measurement of a second power level received by the chargeable device based on one or more tolerance values of the chargeable device. The controller is further configured to determine if a power difference between the first and second adjusted power measurements exceeds a threshold value.

Abstract: Exemplary embodiments are directed to differentially driving a load. An apparatus includes a differential drive amplifier including a switching device coupled with a first output node and a second output node. The first output node and the second output node drive a load network including primary coils. The differential drive amplifier also includes a drive circuit configured to drive the switching device. The drive circuit may be configured to provide a drive signal to the switching device to alter a conductive state of the switching device to produce a first output signal at the first output node and a second output signal at the second output node. The first and second output signals may be substantially equal in magnitude but opposite in polarity relative to a reference voltage.

Abstract: Exemplary embodiments are directed to power conversion. A device may include a controllable switch coupled between an AC network and a DC network. The device may further include control circuitry configured to modify a configuration of the switch based on a detected difference between a reference signal and an output signal at the DC network.

Abstract: This disclosure provides systems, methods and apparatus for detecting wireless charging transmit characteristics. One aspect of the disclosure provides a method of detecting a transmit characteristic in a wireless power transmission device. The device includes a series element electrically coupled to a transmit coil. The method includes determining real and imaginary components of a first voltage at a first terminal of the series element. The method further includes determining real and imaginary components of a second voltage at a second terminal of the series element. The method further includes determining real and imaginary components of a current through the series element, based on the determined first and second voltages. The method further includes determining transmit characteristics such as nodal voltages, currents, power and impedances based on determined voltages and currents.

Abstract: Aspects of a protection circuit and method are disclosed. A transmit circuit generates a power transmit signal for powering the transmit antenna to generate a wireless field sufficient for wirelessly charging a device. A detection circuit senses a strength of an electromagnetic field received by the transmit antenna and further configured to generate an sense signal indicating the strength of the electromagnetic field received by the transmit antenna. A power control circuit controls a switch based at least partly on the sense signal. The power control circuit can attenuate an electrical coupling between the transmit antenna and the transmit circuit such that the received electromagnetic field is inhibited from damaging the transmit antenna or the transmit circuit.

Abstract: Systems, methods, and apparatus for overvoltage protection in a wireless power receiver are disclosed. One aspect of the disclosure is a wireless power receiver apparatus. The apparatus includes an antenna circuit configured to wirelessly receive power, from a transmitter, at a level sufficient to power or charge a load, wherein the antenna circuit is electrically connected to an overvoltage protection circuit that is electrically connected between the antenna circuit and the load. The apparatus also includes a matching circuit electrically connected to the antenna circuit and a switching element electrically connected to the matching circuit. At least one of the matching circuit or the switching element is configured to control an amount of the received power flowing into the overvoltage protection circuit.