Wireless circuitry is provided that includes a radio-frequency amplifier or mixer, a power detector coupled to an input or an output of the radio-frequency amplifier or mixer, and a transimpedance amplifier coupled to an output of the power detector. The transimpedance amplifier can be implemented as a class A amplifier, a class AB amplifier, or an enhanced class AB amplifier. The power detector can include an input transistor having a gate terminal configured to receive a radio-frequency signal, a bias transistor, and a voltage generator configured to apply a calibration voltage to a gate terminal of the bias transistor to mitigate a direct current (DC) offset associated with the power detector.

Wireless circuitry is provided that includes a radio-frequency amplifier or mixer, a power detector coupled to an input or an output of the radio-frequency amplifier or mixer, and a transimpedance amplifier coupled to an output of the power detector. The transimpedance amplifier can be implemented as a class A amplifier, a class AB amplifier, or an enhanced class AB amplifier. The power detector can include an input transistor having a gate terminal configured to receive a radio-frequency signal, a bias transistor, and a voltage generator configured to apply a calibration voltage to a gate terminal of the bias transistor to mitigate a direct current (DC) offset associated with the power detector.

An apparatus and method for lost power detection are described. In one implementation, an apparatus for wireless transferring power comprises a wireless power transmitter configured to wirelessly transmit power at a power level sufficient to power or charge a chargeable device. The apparatus further comprises a controller configured to determine a first and second power difference between a first and second power measurement and the second and a third power measurement of the power level provided by the wireless power transmitter at a first, second, and third sample time, respectively. The controller is further configured to determine a transmitter power difference between the first power difference and the second power difference. The controller is further configured to determine an absence or a presence of an object that affects consumption of power transmitted by the wireless power transmitter based at least on the transmitter power difference _T.

An apparatus and method for lost power detection are described. In one implementation, an apparatus for wireless transferring power comprises a wireless power transmitter configured to wirelessly transmit power at a power level sufficient to power or charge a chargeable device. The apparatus further comprises a controller configured to determine a first and second power difference between a first and second power measurement and the second and a third power measurement of the power level provided by the wireless power transmitter at a first, second, and third sample time, respectively. The controller is further configured to determine a transmitter power difference between the first power difference and the second power difference. The controller is further configured to determine an absence or a presence of an object that affects consumption of power transmitted by the wireless power transmitter based at least on the transmitter power difference _T.

Systems, methods and apparatus are disclosed for detecting power losses due to induction heating in wireless power receivers. In one aspect, an apparatus for wireless power transfer comprises a power transfer component configured to transmit wireless power to a wireless power receiver at a power level sufficient to charge or power a load. The apparatus further comprises a communications receiver configured to receive a message from the wireless power receiver, the message comprising a group identifier. The apparatus further comprises a controller circuit operationally coupled to the power transfer component and the communications receiver and configured to determine a power loss value based on the group identifier, the power loss value indicative of power loss due to induction heating presented by one or more wireless power receivers that are members of a group associated with the group identifier.

Systems, methods and apparatus are disclosed for detecting power losses due to induction heating in wireless power receivers. In one aspect, an apparatus for wireless power transfer comprises a power transfer component configured to transmit wireless power to a wireless power receiver at a power level sufficient to charge or power a load. The apparatus further comprises a communications receiver configured to receive a message from the wireless power receiver, the message comprising a group identifier. The apparatus further comprises a controller circuit operationally coupled to the power transfer component and the communications receiver and configured to determine a power loss value based on the group identifier, the power loss value indicative of power loss due to induction heating presented by one or more wireless power receivers that are members of a group associated with the group identifier.

An electrical activity sensor is attachable to a power cable of an electrical device and includes a magnetometer for detecting a variation of magnetic field caused by current in the power cable when the electrical device is powered. A processor is configured to determine electrical activity of the electrical device based on the detected variation of magnetic field. An antenna is provided for transmitting a signal representative of the electrical activity to a reader device.

A method for emulating a reactive source impedance for a generator connected to a load. The method comprises adjusting an output of the generator, wherein, in response to adjustment of the output, a first measured value M1 calculated with respect to a weighted sum of voltage v, current i and derivatives of the voltage v and the current i tends to a first setpoint S1 for M1. The method also includes receiving a second setpoint S2 for a second measured value M2 and adjusting S1 to adjust the second measured value M2 of a conventional measure of generator output towards the second setpoint S2 for M2, wherein holding M1 constant emulates a desired source impedance of the generator.

An apparatus for wireless communications includes a power amplifier, a low-noise amplifier, a power detector, and a transformer. The transformer includes a first inductor coupled to an output of the power amplifier, and a second inductor coupled to an antenna, wherein the second inductor is magnetically coupled with the first inductor. The transformer also includes a third inductor coupled to an input of the low-noise amplifier, wherein the third inductor is magnetically coupled with the second inductor. The transformer also includes a coupling inductor coupled to an input of the power detector, wherein the coupling inductor is magnetically coupled with at least one of the first inductor and the second inductor.

Wireless circuitry is provided that includes a radio-frequency amplifier or mixer, a power detector coupled to an input or an output of the radio-frequency amplifier or mixer, and a transimpedance amplifier coupled to an output of the power detector. The transimpedance amplifier can be implemented as a class A amplifier, a class AB amplifier, or an enhanced class AB amplifier. The power detector can include an input transistor having a gate terminal configured to receive a radio-frequency signal, a bias transistor, and a voltage generator configured to apply a calibration voltage to a gate terminal of the bias transistor to mitigate a direct current (DC) offset associated with the power detector.