Embodiments disclosed herein describe a wireless power receiver including a synchronous transistor rectifier using a Class-E or a Class-F amplifier. The wireless power receiver includes at least one radio frequency (RF) antenna configured to generate an alternating current (AC) waveform from received RF waves. The wireless power receiver further includes a power line configured to carry a first signal based on the AC current generated by the least one RF antenna, and a tap-line coupled to the power line, the tap-line being configured to carry a second signal. The second signal is based on the AC current generated by the least one RF antenna and distinct from the first signal. The wireless power receiver also includes a transistor coupled to at least the power line and the tap-line. The transistor is configured to provide a direct current (DC) waveform to a load based on the first and second signals.

Provided is a power amplifier circuit that can increase output power and also reduce the effect of intermodulation distortion. The power amplifier circuit includes a power divider, a distortion compensation circuit provided on the secondary path, a power combiner, and a first amplifier configured. The distortion compensation circuit includes a generation circuit configured to generate the second-harmonic wave of the input signal, a filter circuit configured to attenuate the fundamental wave and pass the second-harmonic wave, and a phase adjustment circuit configured to adjust the phase of the second-harmonic wave.

This application relates to amplifier circuitry, in particular class-D amplifiers, operable in open-loop and closed-loop modes. An amplifier (300) has a forward signal path for receiving an input signal (S.sub.IN) and outputting an output signal (S.sub.OUT) and a feedback path operable to provide a feedback signal (S.sub.FB) from the output. A feedforward path provide a feedforward signal (S.sub.FF) from the input and a combiner (105) is operable to determine an error signal (ε) based on a difference between the feedback signal and the feedforward signal. The feedforward comprises a compensation module (201) configured to apply a controlled transfer function to the feedforward signal in the closed-loop mode of operation, such that an overall transfer function for the amplifier is substantially the same in the closed-loop mode of operation and the open-loop mode of operation.

Methods and systems for optimizing amplifier operations are described. The described methods and systems particularly describe a feed-forward control circuit that may also be used as a feed-back control circuit in certain applications. The feed-forward control circuit provides a control signal that may be used to configure an amplifier in a variety of ways.

Provided is a power amplifier circuit that can increase output power and also reduce the effect of intermodulation distortion. The power amplifier circuit includes a power divider, a distortion compensation circuit provided on the secondary path, a power combiner, and a first amplifier configured. The distortion compensation circuit includes a generation circuit configured to generate the second-harmonic wave of the input signal, a filter circuit configured to attenuate the fundamental wave and pass the second-harmonic wave, and a phase adjustment circuit configured to adjust the phase of the second-harmonic wave.

This application relates to amplifier circuitry, in particular class-D amplifiers, operable in open-loop and closed-loop modes. An amplifier (300) has a forward signal path for receiving an input signal (S.sub.IN) and outputting an output signal (S.sub.OUT) and a feedback path operable to provide a feedback signal (S.sub.FB) from the output. A feedforward path provide a feedforward signal (S.sub.FF) from the input and a combiner (105) is operable to determine an error signal (ε) based on a difference between the feedback signal and the feedforward signal. The feedforward comprises a compensation module (201) configured to apply a controlled transfer function to the feedforward signal in the closed-loop mode of operation, such that an overall transfer function for the amplifier is substantially the same in the closed-loop mode of operation and the open-loop mode of operation.

Broadband feedforward power amplifiers are disclosed herein. In certain embodiments, a broadband feedforward power amplifier includes a power amplifier electrically connected between a radio frequency (RF) input and an RF output, and a feedforward compensation circuit including a first amplifier electrically connected in parallel with the power amplifier, a load impedance, and a second amplifier electrically connected between the radio frequency input and the load impedance. The feedforward compensation circuit generates a compensation signal based on sensing an output of the first amplifier and an output of the second amplifier, and provides the compensation signal to the radio frequency output to thereby compensate the power amplifier for non-linearity.

A system and method for digital receiver linearization is provided. An input digital signal is accepted with a plurality of spectral components. The input digital signal may be either a radio frequency (RF) digital signal or a baseband digital signal. Nonlinear distortion is created in response to the input digital signal. As the result of a corrected input digital signal, a primary baseband signal is created with real (I) and imaginary quadrature (Q) components. In response to the nonlinear distortion, auxiliary baseband signals are created with real (I.sub.AUX) and imaginary quadrature (Q.sub.AUX) components. The primary baseband signal is compared to the auxiliary baseband signals to supply complex amplitude correction coefficients. The complex amplitude correction coefficients are used to modify the nonlinear distortion, and the modified nonlinear distortion is subtracted from the input digital signal to supply the corrected input digital signal.

Provided is a power amplifier circuit that can increase output power and also reduce the effect of intermodulation distortion. The power amplifier circuit includes a power divider, a distortion compensation circuit provided on the secondary path, a power combiner, and a first amplifier configured. The distortion compensation circuit includes a generation circuit configured to generate the second-harmonic wave of the input signal, a filter circuit configured to attenuate the fundamental wave and pass the second-harmonic wave, and a phase adjustment circuit configured to adjust the phase of the second-harmonic wave.

An amplifier circuit is disclosed. The amplifier circuit includes an input terminal configured to receive an input signal, an output terminal configured to transmit an output signal, and a first signal path including a first amplifying circuit, where the first amplifying circuit is configured to receive the input signal and to transmit a first amplified output to the output terminal, and where the first amplified output includes first amplifier circuit harmonic noise. The amplifier circuit also includes a second signal path including a second amplifying circuit, where the second amplifying circuit receives the input signal and transmits a second amplified output to the output terminal, and where the second amplified output includes second amplifier circuit harmonic noise. The output signal includes the first and second amplified outputs, and the first amplifying circuit harmonic noise is at least partially canceled by the second amplifying circuit harmonic noise in the output signal.