Abstract: A system includes a switch network coupled to a power source, wherein the switch network comprises a plurality of power switches, a transmitter resonant tank coupled to the plurality of power switches, wherein the transmitter resonant tank comprises a first variable capacitance network, a transmitter coil coupled to the transmitter resonant tank, and a first receiver comprising a first receiver coil configured to be magnetically coupled to the transmitter coil, and a first receiver resonant tank coupled to the first receiver coil, wherein the first receiver resonant tank comprises a second variable capacitance network.

Abstract: A system comprises a power amplifier configured to receive a frequency control signal, wherein the frequency control signal is generated based upon a system clock of a communication device and the frequency control signal is used to control a switching frequency of the power amplifier and a first resonant circuit coupled between the power amplifier and a first coil, wherein the first resonant circuit comprises a first variable capacitance network.

Abstract: A device comprises a switch network coupled to a power source, wherein the switch network comprises a plurality of power switches, a transmitter resonant tank coupled to the plurality of power switches, wherein the transmitter resonant tank comprises a primary resonant capacitor, a transmitter coil coupled to the transmitter resonant tank and a harmonic reduction apparatus coupled between the switch network and the transmitter coil, wherein the harmonic reduction apparatus is configured to attenuate at least one undesired frequency component.

Abstract: A power converter comprises a primary switch network coupled to a power source, wherein the primary switch network comprises a plurality of power switches, a controller configured to generate gate drive signals for the plurality of power switches, a secondary rectifier coupled to an output, a first transformer having a first winding coupled to the primary switch network, a second winding coupled to the secondary rectifier and a third winding coupled to the controller and a second transformer having a fourth winding coupled to the primary switch network, a fifth winding coupled to the secondary rectifier and a sixth winding coupled to the controller, wherein a voltage signal from the third winding and/or the sixth winding is processed to provide a feedback of a voltage at the output.

Abstract: A system comprises a primary switch network coupled to a power source, wherein the primary switch network comprises a plurality of power switches, a primary resonant tank coupled to the plurality of power switches, wherein a resonant capacitor of the primary resonant tank is formed by a first variable capacitance network, and wherein the first variable capacitance network is modulated to improve soft switching of the plurality of power switches through reducing a voltage level and a current level of a switch at a turn-on instant and a primary coil coupled to the primary resonant tank.

Abstract: A structure comprises a plurality of first turns of a coil and a plurality of second turns of the coil having a similar shape as the plurality of first turns of the coil, wherein the plurality of first turns of the coil and the plurality of second turns of the coil have a similar center position and a current flowing through the plurality of first turns of the coil and a current flowing through the plurality of second turns of the coil are in opposite directions.