A batteryless wireless sensor system includes a data acquisition system, a radio frequency (RF) transceiver, and a batteryless wireless sensor device. The RF transceiver is in communication with the data acquisition system, transmits a RF signal, and receives sensor data and provide the sensor data to the data acquisition system. The batteryless wireless sensor device includes a RF transmitter, an analog to digital converter (ADC), and a sensor. The batteryless wireless sensor harvests energy from the RF signal and generates a DC signal based on the energy harvested from the RF signal, powers up and operates the ADC and the sensor based on the DC signal, and generates sensor data. The batteryless wireless sensor then transmits the sensor data via the RF transmitter to the RF transceiver. In certain examples, the ADC is implemented as a current mode ADC.

A system and method for bi-directional communication through capacitive coupling is achieved with capacitive plates within the environment of a wireless power transfer system. Data is transferred using capacitance over a separate path from the transfer of electrical power in the wireless power transfer system.

A wireless power transmission system includes a power transmitter that outputs a power transmission radio wave, a plurality of wireless sensors that receive power, and at least one human body tag to be carried on a human body in an environment. The power transmitter communicates with the at least one human body tag in each slot to estimate power exposure on a human body per slot for a human body carrying the at least one human body tag, calculates power exposure on a human body per cycle as an average of power exposure on a human body for all slots, and limits power transmission to the wireless sensors in response to the power exposure on a human body per cycle exceeding a predetermined value.

In an embodiment, an electronic device includes a first near field communication module, at least one second communication module, at least one portion of a volatile memory, at least one register, and at least one first circuit configured to activate the near field communication module, wherein the at least one second communication module is configured to power the at least one portion of the volatile memory, the at least one register and the at least one first circuit with a first supply voltage when the electronic device is in an on state and when the first near field communication module is in a standby mode.

An inductive power transfer system is arranged to transfer power from a power transmitter to a power receiver via a wireless power signal. The system supports communication from the power transmitter to the power receiver based on load modulation of the power signal. The power receiver transmitting a first message to the power transmitter which comprises a standby power signal requirement for the power signal during a standby phase. The power transmitter receives the message, and when the system enters the standby phase, the power transmitter provides the power signal in accordance with the standby power signal requirement during. A power receiver configurable standby phase is provided which may for example allow devices to maintain battery charge or to provide fast initialization of the power transfer phase.

An antenna module according to one embodiment of the present invention, comprises: a coil layer including a wound first coil; a shield layer disposed on the coil layer and including a plurality of sequentially stacked magnetic sheets; and a protection layer disposed on the shield layer, wherein the thickness of an edge of the shield layer is greater than the thickness of the center of the shield layer, and the total separation distance between the plurality of magnetic sheets at the edge of the shield layer is greater than the total separation distance between the plurality of magnetic sheets at the center of the shield layer.

A method for operating a wireless control device includes the starting up of a control circuit following the actuation, by a user, of a control unit coupled to an energy harvesting device to recharge an energy reserve which electrically powers the control device; the sending of a control message including a control command; the comparison of the elapsed time since the starting up of the control circuit with a first threshold value; when the elapsed time is greater than or equal to the first threshold value, the sending of a pairing request message to the electronic unit.

This application provides a wireless charger and a control method. The wireless charger includes a class-E power amplifier and a tunable impedance circuit that is connected to an output end of the class-E power amplifier. The class-E power amplifier includes a switching transistor and a tunable capacitance circuit that is parallelly connected to the switching transistor. The wireless charger further includes a control unit, configured to obtain a constraint condition of the class-E power amplifier; determine N1 target equivalent load impedances of the class-E power amplifier based on the constraint condition; and adjust a capacitance value of the tunable capacitance circuit in the class-E power amplifier, and adjust an impedance value of the tunable impedance circuit, to enable an equivalent load impedance of the class-E power amplifier to match one of the N1 target equivalent load impedances.

A wireless power transmission method executed by a power transmitter comprising multi-coils, according to one embodiment of the present invention, comprises the steps of: detecting a second power receiver while transmitting power to a first power receiver; determining at least one primary coil adequate for power transmission; by using the determined at least one primary coil, determining whether the second power receiver supports a shared mode protocol; and if the second power receiver supports the shared mode protocol, transmitting power to the first and second power receivers according to the shared mode protocol, wherein the shared mode protocol may be a protocol for simultaneously managing information exchanges between the power transmitter and multiple power receivers.

Apparatuses including multiple selectable circuit elements are described. In an example, an apparatus may include a power supply configured to output a voltage. The apparatus may further include a controller connected to the power supply and a transmission unit connected to the controller. The transmission unit may be configured to output power. The transmission unit may include comprising an inverter connected to the power supply. The inverter may include a high-side switching element. The transmission unit may further include a circuit element a circuit connected to the power supply. The circuit may be configured to select the circuit element. The circuit may include a switch connected between the inverter and the circuit element. The switch and the high-side switching element may be configured to be driven by the voltage outputted by power supply. The controller may be configured to control the power being outputted by the transmission unit.