Abstract:
An amplifier includes an amplifier circuit comprising a switch, the switch configured to provide an output signal responsive to an input signal, the output signal comprising a first output signal at a fundamental frequency and a second signal at a second harmonic of the fundamental frequency, the input signal configured to control the switch according to a nominal 25% off, 75% on cycle, a filter circuit configured to control an impedance presented to the amplifier circuit and a load circuit, at least a part of which is configured to combine with the filter circuit to form an impedance transformation circuit configured to be resonant at the second harmonic of the fundamental frequency.
Abstract:
Systems and methods for wireless power transmission are described herein. In one aspect, an apparatus for wireless power transmission comprises a first antenna array of antenna coils configured to generate a first wireless field. A second antenna array of antenna coils generates a second wireless field. The first antenna array at least partially overlaps the second antenna array. A driver circuit generates first and second drive signals for generation of the first and second wireless fields via the first and second antenna arrays, respectively. The first wireless field is orthogonal with respect to the second wireless field. The first antenna array and the driver circuit power the antenna coils of the first antenna array with alternating polarities. The second antenna array and the driver circuit power the antenna coils of the second antenna array with alternating polarities.
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. The method further includes adjusting a characteristic of a wireless power transmission based on the determined transmit characteristics.
Abstract:
This disclosure provides systems, methods, and apparatus for the limiting of voltage in wireless power receivers. In one aspect, an apparatus includes a power transfer component configured to receive power wirelessly from a transmitter. The apparatus further includes a circuit coupled to the power transfer component and configured to reduce a received voltage when activated. The apparatus further includes a controller configured to activate the circuit when the received voltage reaches a first threshold value and configured to deactivate the circuit when the received voltage reaches a second threshold value. The apparatus further includes an antenna configured to generate a signal to the transmitter that signals to the transmitter that the received voltage reached the first threshold value.
Abstract:
An amplifier includes an amplifier circuit comprising a switch, the switch configured to provide an output signal responsive to an input signal, the output signal comprising a first output signal at a fundamental frequency and a second signal at a second harmonic of the fundamental frequency, the input signal configured to control the switch according to a nominal 25% off, 75% on cycle, a filter circuit configured to control an impedance presented to the amplifier circuit and a load circuit, at least a part of which is configured to combine with the filter circuit to form an impedance transformation circuit configured to be resonant at the second harmonic of the fundamental frequency.
Abstract:
A wireless power transfer antenna includes a primary antenna portion configured to develop a primary electric field (E-field) and a primary magnetic field (B-field), and an auxiliary winding coupled to the primary antenna portion by the B-field, the auxiliary winding configured to develop an auxiliary electric field (E-field) that combines with the primary E-field resulting in a net E-field that has a magnitude that is smaller than a magnitude of the primary E-field.
Abstract:
This disclosure provides systems, methods, and apparatus for the limiting of voltage in wireless power receivers. In one aspect, an apparatus includes a power transfer component configured to receive power wirelessly from a transmitter. The apparatus further includes a circuit coupled to the power transfer component and configured to reduce a received voltage when activated. The apparatus further includes a controller configured to activate the circuit when the received voltage reaches a first threshold value and configured to deactivate the circuit when the received voltage reaches a second threshold value. The apparatus further includes an antenna configured to generate a signal to the transmitter that signals to the transmitter that the received voltage reached the first threshold value.
Abstract:
This disclosure provides systems, methods and apparatus for tuning a wireless power transmitter. In one aspect a device configured to wirelessly provide power to a load is provided. The device includes a signal driver configured to provide power along a power path. The device further includes a first tuning circuit along the power path, configured to tune reactance at the signal driver, introducing undesired harmonic content. The device further includes a second tuning circuit along the power path, configured to tune reactance at the signal driver and to generate complementary harmonic content, at least partly canceling the harmonic generated at the first tuning circuit.
Abstract:
Systems, methods, and apparatus are provided for tuning in wireless power transfer circuits. One aspect of the disclosure provides an apparatus for tuning. The apparatus includes a field effect transistor having a gate, source, and drain, where the field effect transistor is configured to electrically engage a tuning element to an AC power path. In some embodiments, one of the source or drain contacts is at an alternating current voltage.
Abstract:
Aspects of a protection circuit and method are disclosed. An apparatus to transmit wireless power comprises a transmit antenna, a driver, a sensing circuit, and a control circuit. The transmit antenna generates a wireless field to charge devices. The driver powers the transmit antenna for generation of the wireless field. A power level of the wireless field is based on a power level of the driver. The sensing circuit senses wireless power received at the transmit antenna and generates a monitoring signal based on the sensed wireless power received at the transmit antenna. The control circuit controls the power level or inhibits the driver from powering the transmit antenna when the monitoring signal indicates that the transmit antenna is receiving wireless power from a foreign antenna.