In accordance with an embodiment, a wireless power transmitter includes a charging surface, a transmitting antenna configured to generate an electromagnetic field extending above the charging surface, a sensing array disposed between the transmitting antenna and the charging surface, and a controller coupled to the sensing array. The sensing array includes a plurality of sensors. Each sensor of the plurality of sensors is configured to generate a respective signal indicative of a strength of the electromagnetic field. The controller is configured to detect a presence of a metallic object, other than a receiving antenna of a power receiver, in the electromagnetic field based on the respective signal generated by one or more sensors of the plurality of sensors.

An outphasing amplifier includes a first class-E power amplifier having an output coupled to a first conductor and an input receiving a first RF drive signal. A first reactive element is coupled between the first conductor and a second conductor. A second reactive element is coupled between the second conductor and a third conductor. A second class-E power amplifier includes an output coupled to a fourth conductor and an input coupled to a second RF drive signal, a third reactive element coupled between the second and fourth conductors. Outputs of the first and second power amplifiers are combined by the first, second and third reactive elements to produce an output current in a load. An efficiency enhancement circuit is coupled between the first and fourth conductors to improve power efficiency at back-off power levels. Power enhancement circuits are coupled to the first and fourth conductors, respectively.

Methods and apparatus for a body diode conduction sensor configured for coupling to a switching element. In embodiments, the sensor comprises first and second voltage divider networks coupled to a voltage source and a diode coupled to the switching element and to the first voltage divider network, wherein the diode is conductive at times corresponding to body diode conduction of the switching element decreasing the DC average voltage at the output node of the first voltage divider network. A differential output voltage can be coupled to the first and second voltage divider networks with an output signal corresponding to a time of the body diode conduction of the switching element.

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.

In some implementations, there is provided an apparatus comprising a resonant amplifier circuit including a first inductor having a first inductive input and a first inductive output; a second inductor having a second inductive input and a second inductive output; a first switch coupled to the first inductive output; and a second switch coupled to the second inductive output, wherein the first switch and the second switched are driven out of phase, wherein the first inductor is configured to be resonant with a first capacitance associated with the first switch, and wherein the second inductor is configured to be resonant with a second capacitance associated with the second switch. Related systems and articles of manufacture are also provided.

Embodiments of the present disclosure include a harmonic power amplifying circuit with high efficiency and high bandwidth and a radio-frequency power amplifier. The circuit comprises an input matching network (11), a transistor (M), and an output matching network (12); a gate of the transistor (M) connected to an output end of the input matching network (11), a drain thereof connected to an input end of the output matching network (12), and a source thereof being grounded; wherein the output matching network (12) enables a lower sideband of the harmonic power amplifying circuit to work in a continuous inverse F amplification mode and an upper sideband of the harmonic power amplifying circuit to work in a continuous F amplification mode; wherein the output matching network (12) and a parasitic network of the transistor (M) form a low pass filter. By transitioning from the continuous inverse F power amplifier working mode to the continuous F power amplifier working mode, the efficiency of a continuous harmonic control power amplifier is effectively improved to be higher than 60%, a relative bandwidth is improved to be higher than 80%, and the harmonic impedance is simple to match and easy to realize.

An apparatus is provided that includes circuitry for decomposing an input signal to multiple substantially constant-envelope components and an outphasing path for each substantially constant-envelope component. The apparatus also includes a modulator for discrete phase control in each outphasing path, an amplifier in each outphasing path and a combiner for combining output signals from the outphasing paths. A system and method are also provided.

A bidirectional wireless power transfer system for transferring power comprises a power stage electrically connected to a transceiver element for an electric field and/or a magnetic field, and for extracting power from a generated electric field and/or a generated magnetic field. The power stage is for inverting an inputted power signal and for rectifying a received power signal. The system further comprises a trigger circuit for synchronizing wireless power transfer; and a clock generator for generating a clock signal. The system further comprises a switching element electrically connected to the power stage, and selectively electrically connected to the trigger circuit and the clock generator, such that: when the switching element electrically connects the clock generator to the power stage, the transceiver element is configured to transfer power by generating an electric field and/or a magnetic field, and when the switching element electrically connects the trigger circuit to the power stage, the transceiver element is configured to extract power from a generated electric field and/or a generated magnetic field.

A modulated RF carrier produced at the output of the polar transmitter's switch-mode power amplifier (SMPA) is conveyed to an output filter network comprising a harmonic low-pass filter (LPF) connected in parallel with an absorptive high-pass filter (HPF). Together the harmonic LPF and absorptive HPF pass the fundamental component of the modulated RF carrier to the polar transmitter's load while also absorbing higher harmonic components that would otherwise be undesirably reflected back toward the output of the SMPA.

The electronic circuits and semiconductor device having the same are provided. The electronic circuit includes: a first transistor including a first electrode coupled with an input voltage; a second transistor including a first electrode coupled with a second electrode of the first transistor; a first capacitor coupled between the first transistor and the second transistor; a first diode including a first terminal coupled with the first electrode of the first transistor; a second diode including a first terminal coupled with a second terminal of the first diode and a second terminal coupled with a second electrode of the second transistor; a second capacitor coupled between the first transistor and the first diode; and a third capacitor coupled between the first diode and the second transistor.