Abstract: Described herein are multi-level inverters configured for a wireless power system and methods for such inverters and systems. The inverter includes at least one capacitor and at least one switching leg. Each switching leg including a plurality of switches having at least one switch coupled to the at least one capacitor. The plurality of switches of each switching leg are configured to be controlled such that, during operation: (i) an output voltage is produced, the output voltage having an asymmetric multilevel profile with at least four non-zero unequal voltage levels and (ii) at least one switch of the plurality of switches operates with zero-voltage switching.

Abstract: Described herein are controllers configured for a wireless power system and methods for such controllers and systems. The controller includes a control module configured to generate a first control signal having a first voltage level and a second control signal having a second voltage level and a modulator configured to (a) receive a signal representative of the output current and (b) generate carrier signals based on the output current. When a first carrier signal is greater than the first voltage level, a first gate drive signal for a first switch is high and when a second carrier signal is greater than the second voltage level, a second gate drive signal for a second switch is high, thereby driving an inverter to output a multi-level voltage having a first output level based on the first drive signal and a second output level based on the second drive signal.

Abstract: A wireless power receiver includes one or more tunable capacitors in parallel with an inductor. The wireless power receiver adapted to receive an induced voltage input at the inductor due to a magnetic field generated by a wireless power transmitter. The rectifier has an output with a rectified voltage and a rectified current. A controller has a first input for receiving a signal representative of the rectified voltage and a first output for supplying an adjustment signal to the tunable capacitor. The controller includes a processor coupled to the first input and is configured to operate on the signal representative of rectified voltage to produce a desired capacitance value for capacitor and provide the adjustment signal determined so as to adjust a capacitance value of capacitor to the desired capacitance value.

Abstract: A wireless power receiver includes one or more tunable capacitors in parallel with an inductor. The wireless power receiver adapted to receive an induced voltage input at the inductor due to a magnetic field generated by a wireless power transmitter. The rectifier has an output with a rectified voltage and a rectified current. A controller has a first input for receiving a signal representative of the rectified voltage and a first output for supplying an adjustment signal to the tunable capacitor. The controller includes a processor coupled to the first input and is configured to operate on the signal representative of rectified voltage to produce a desired capacitance value for capacitor and provide the adjustment signal determined so as to adjust a capacitance value of capacitor to the desired capacitance value.

Abstract: A wireless power receiver includes one or more tunable capacitors in parallel with an inductor. The wireless power receiver adapted to receive an induced voltage input at the inductor due to a magnetic field generated by a wireless power transmitter. The rectifier has an output with a rectified voltage and a rectified current. A controller has a first input for receiving a signal representative of the rectified voltage and a first output for supplying an adjustment signal to the tunable capacitor. The controller includes a processor coupled to the first input and is configured to operate on the signal representative of rectified voltage to produce a desired capacitance value for capacitor and provide the adjustment signal determined so as to adjust a capacitance value of capacitor to the desired capacitance value.

Abstract: The disclosure features wireless power transmitters configured to detect a radio frequency identification (RFID) tag, the transmitters including a transmitter resonator, a transmitter impedance matching network coupled to the transmitter resonator, an amplifier coupled to the transmitter impedance matching network, a detection subsystem connected to the transmitter resonator, and a controller coupled to the amplifier and to the detection subsystem and configured so that during operation of the transmitter, the controller is configured to control the transmitter resonator, the amplifier, and the impedance matching network to cycle the transmitter between a power transmission mode and a RFID tag detection mode.

Abstract: The disclosure features resonators to wirelessly transfer energy to a wireless power device including a device resonator coil having a dimension D. The resonator can include a first plurality of conductor windings wound approximately in a first plane and having first and second conductor leads, and a second plurality of conductor windings wound in a second plane and having third and fourth conductor leads. The first and third conductor leads can be coupled to each other and the second and the fourth conductor leads can be coupled to at least one capacitor. The first plane and second plane can be spaced apart by separation S and substantially parallel. The separation S between the first plane and second plane can be approximately equal to or greater than the dimension D of the device resonator coil.

Abstract: A wireless power receiver includes one or more tunable capacitors in parallel with an inductor. The wireless power receiver adapted to receive an induced voltage input at the inductor due to a magnetic field generated by a wireless power transmitter. The rectifier has an output with a rectified voltage and a rectified current. A controller has a first input for receiving a signal representative of the rectified voltage and a first output for supplying an adjustment signal to the tunable capacitor. The controller includes a processor coupled to the first input and is configured to operate on the signal representative of rectified voltage to produce a desired capacitance value for capacitor and provide the adjustment signal determined so as to adjust a capacitance value of capacitor to the desired capacitance value.

Abstract: The disclosure features wireless power transmitters configured to detect a radio frequency identification (RFID) tag, the transmitters including a transmitter resonator, a transmitter impedance matching network coupled to the transmitter resonator, an amplifier coupled to the transmitter impedance matching network, a detection subsystem connected to the transmitter resonator, and a controller coupled to the amplifier and to the detection subsystem and configured so that during operation of the transmitter, the controller is configured to control the transmitter resonator, the amplifier, and the impedance matching network to cycle the transmitter between a power transmission mode and a RFID tag detection mode.

Abstract: The disclosure features mobile electronic devices configured to be wirelessly charged, the devices featuring a receiver resonator configured to capture oscillating magnetic flux, the receiver resonator including: a conductive material layer defining an aperture and a slit extending from the aperture to an outer edge of the conductive material layer, where the conductive material layer forms a back cover of the mobile electronic device, and an inductor having first and second conductor traces, the first trace coupled to a first portion of the conductive material layer adjacent to a first side of the slit and the second trace coupled to a second portion of the conductive material layer adjacent to a second side of the slit.

Abstract: The disclosure features resonators to wirelessly transfer energy to a wireless power device including a device resonator coil having a dimension D. The resonator can include a first plurality of conductor windings wound approximately in a first plane and having first and second conductor leads, and a second plurality of conductor windings wound in a second plane and having third and fourth conductor leads. The first and third conductor leads can be coupled to each other and the second and the fourth conductor leads can be coupled to at least one capacitor. The first plane and second plane can be spaced apart by separation S and substantially parallel. The separation S between the first plane and second plane can be approximately equal to or greater than the dimension D of the device resonator coil.