Abstract: Systems, methods and apparatus are disclosed for a dual mode wireless power receiver. In accordance with on aspect, an apparatus for receiving wireless power is provided. The apparatus includes a first coil configured to wirelessly receive power from a first transmitter configured to generate a first alternating magnetic field having a first frequency. The apparatus further includes a second coil configured to wirelessly receive power from a second transmitter configured to generate a second alternating magnetic field having a second frequency higher than the first frequency. The second coil is positioned to enclose the first coil. A first coupling factor between the first coil and a coil of the first transmitter is higher than a second coupling factor between the second coil and a coil of the second transmitter when the first and second coils are positioned within respective charging regions of the first and second transmitters.

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: Exemplary embodiments are directed to wireless power transfer including a plurality of antenna circuits spatially arranged and each including an antenna configured to resonate and generate a near field coupling mode region thereabout in response to a driving signal from a power amplifier. The apparatus further includes a processor configured to control activation of resonance of each of the plurality of antenna circuits. The method for wirelessly charging includes driving a signal from a power amplifier and controlling activation of resonance of a plurality of antenna circuits spatially arranged and each including an antenna configured to resonate in response to the driving signal.

Abstract: Systems and methods for low loss wireless power transmission are described herein. In one aspect, a transmission coil for transmitting wireless power comprises a first and second spiral coil. Each spiral coil comprises a plurality of turns. A center of the first spiral coil to an outermost turn of the first spiral coil defines a first cross section, and a center of the second spiral coil to an outermost turn of the second spiral coil defines a second cross section. Portions of the first spiral coil along the first cross section and the second spiral coil along the second cross section have a mutual inductance with respect to a receive coil greater than 65% of a maximum mutual inductance along the first and second cross sections. The second spiral coil is counter-wound relative to the first spiral coil.

Abstract: This disclosure provides systems, methods and apparatus for tuning a transmit antenna for operation in a plurality of frequency bands. In one aspect, a transmitting antenna system is provided. The transmitting antenna system includes an active transmit antenna and a tunable passive antenna. The active antenna is configured to transmit a field over a plurality of operating frequencies. The passive antenna is configured to transmit a field over at least two frequencies of the plurality of operating frequencies. In one aspect, the tunable passive antenna includes a network of a plurality of reactive elements. In another aspect, the plurality of operating frequencies is selected from a set including a charging frequency, an NFC frequency, and a communication frequency.

Abstract: This disclosure provides systems, methods, and apparatus for filtering of a rectifier in a wireless power receiver. In one aspect a wireless power receiver apparatus is provided. The receiver apparatus includes a coil circuit configured to wirelessly receive power via a wireless field. The receiver apparatus further includes a rectifier circuit configured to provide direct-current (DC) based at least in part on the received power. The receiver apparatus further includes a first filter circuit electrically connected between the coil and the rectifier circuit and configured to reduce emissions from the rectifier circuit and configured to maintain a first impedance presented by the rectifier circuit substantially equal to a second impedance presented to the coil circuit. The receiver apparatus further includes a band-stop filter circuit configured to electrically isolate emissions from the rectifier circuit.

Abstract: This disclosure provides systems, methods, and apparatus for filtering of a rectifier in a wireless power receiver. In one aspect a wireless power receiver is provided. The wireless power receiver includes a rectifier circuit configured to provide direct-current (DC) based at least in part on a time-varying voltage generated via a wireless field provided from a wireless power transmitter. The wireless power receiver further includes a band-stop filter circuit configured to filter an output of the rectifier circuit and electrically isolate a capacitor from the rectifier circuit at an operating frequency.

Abstract: This disclosure provides systems, methods and apparatus for tuning a wireless power transmitter. In one aspect an apparatus configured to wirelessly provide power to a load is provided. The apparatus includes a transmit circuit including a transmit coil. The transmit circuit is configured to wirelessly provide power to the load. The transmit coil is configured to resonate at a resonant frequency. The transmit circuit has a reactance. The apparatus further includes a detection circuit configured to detect a change in the resonant frequency while providing power to the load. The apparatus further includes a tuning circuit configured to adjust the reactance based on the change.

Abstract: Exemplary embodiments are directed to wireless power devices. A device may include a transmit antenna and a metallic structure spaced from and configured for detuning the transmit antenna. The device may further include a circuit for tuning the transmit antenna.

Abstract: A multi-band antenna device includes a primary antenna with a helical component and a folded component. A wire is formed in a helix to construct the helical component and a wire is formed in a folded-over fashion to form the folded component. The folded component is disposed inside the helix. The helical component and folded component may be formed with separate wires or as one continuous wire. The primary antenna is for resonating in multiple frequency bands including a first frequency band correlated with the helical component and a second frequency band correlated with the folded component. A secondary antenna may be included to provide diversity and possibly other frequency bands. The secondary antenna includes a planar inverted F antenna.

Abstract: Exemplary embodiments are directed to wireless power transfer including a plurality of antenna circuits spatially arranged and each including an antenna configured to resonate and generate a near field coupling mode region thereabout in response to a driving signal from a power amplifier. The apparatus further includes a processor configured to control activation of resonance of each of the plurality of antenna circuits. The method for wirelessly charging includes driving a signal from a power amplifier and controlling activation of resonance of a plurality of antenna circuits spatially arranged and each including an antenna configured to resonate in response to the driving signal.

Abstract: Exemplary embodiments are directed to wireless power transfer to an electronic circuit including a wireless charging receive antenna comprising a first loop of an energy receiving conductor and at least another loop of said energy receiving conductor electrically coupled to the first loop. The loops form a multi-turn loop antenna to resonate at a wireless charging frequency and provide wirelessly received power to the electronic device. The multi-turn loop antenna is configured for affixing to a housing of the wireless device.