The present disclosure describes a method and system for linearizing an amplifier using transistor-level dynamic feedback. The method and system enables nonlinear amplifiers to exhibit linear performance using one or more of gain control elements and phase shifters in the feedback path. The disclosed method and system may also allow an amplifier to act as a pre-distorter or a frequency/gain programmable amplifier.

A power amplifier with analog predistortion is disclosed. In one aspect, a signal in the transmission chain is sampled to determine if a phase distortion (delay or advancement) is present. Information about the sampled signal is provided to a control circuit, which uses an analog predistortion circuit to inject a correction signal into the transmission chain so as to offset or compensate for the phase distortion. In an exemplary aspect, the analog predistortion circuit may use a variable capacitor to generate the correction signal that is injected. This detection and adjustment may be done in the front end of the transmission chain so as to avoid reliance on a baseband processor. Use of such analog predistortion helps maintain desired linear operation over the large bandwidths of emerging wireless communication standards.

The present disclosure describes a method and system for linearizing an amplifier using transistor-level dynamic feedback. The method and system enables nonlinear amplifiers to exhibit linear performance using one or more of gain control elements and phase shifters in the feedback path. The disclosed method and system may also allow an amplifier to act as a pre-distorter or a frequency/gain programmable amplifier.

A linear power-amplifier module has a splitter for splitting an input signal into a plurality split signals, a plurality of circuit branches connected to the splitter, each circuit branch for receiving one of the plurality of split signals, and an output connected to the plurality of circuit branches for combining outputs of the plurality of circuit branches and outputting an output signal. Each circuit branch is for receiving one of the plurality of split signals, each circuit branch comprises a class-AB PA operable under a biasing voltage, and one or more circuit branches each has a respective control circuit connected to an input of the class-AB PA thereof.

Phase and amplitude error correction in a transmission circuit is provided. The transmission circuit includes a transceiver circuit, a power management integrated circuit (PMIC), and a power amplifier circuit(s). The transceiver circuit generates a radio frequency (RF) signal(s) from an input vector, the PMIC generates a modulated voltage, and the power amplifier circuit(s) amplifies the RF signal(s) based on the modulated voltage. When the power amplifier circuit(s) is coupled to an RF front-end circuit, unwanted amplitude-amplitude (AM-AM) and amplitude-phase (AM-PM) errors may be created across a modulation bandwidth of the transmission circuit. In this regard, in embodiments disclosed herein, the input vector is equalized based on multiple complex filters to thereby cause the AM-AM and AM-PM errors to be corrected in the transmission circuit. As a result, it is possible to reduce undesired instantaneous excessive compression and/or spectrum regrowth across the modulation bandwidth of the transmission circuit.

An amplifier (300) comprising: a first signal path comprising first amplifier circuitry (105A) configured to receive a first signal (RF1) with a frequency and a variable phase and amplitude at the frequency; a second signal path comprising second amplifier circuitry (105B) configured to receive a second signal (RF2) with the frequency, wherein at least one of the relative phase and amplitude of the second signal is fixed at the frequency; combiner circuitry (106) configured to combine an output of the first amplifier circuitry and the second amplifier circuitry.

A Doherty power amplifier and a method therefor are disclosed. According to one aspect, a Doherty power amplifier includes an input having a first signal path and a second signal path. The first signal path receives a first input signal at a first frequency (f1), splits the first input signal into a first main path signal and a first peak path signal according to a first splitter ratio determined in response to a first envelope of the first input signal. The second signal path receives a second input signal at a second frequency (f2), and splits the second input signal into a second main path signal and a second peak path signal according to a second splitter ratio determined in response to a second envelope of the second input signal.

An amplifier circuit is provided that includes a power amplifier circuit configured to amplify a radio frequency signal by using a power supply voltage V.sub.ET, which can be a discrete voltage, and a variable phase-shift circuit connected to the power amplifier circuit. The variable phase-shift circuit is configured to change the phase-shift amount of a radio frequency signal based on the power supply voltage V.sub.ET.

An example sensing system includes a non-contact sensing electrode configured to sense an electric potential and provide a sensor signal at an output of the sensing electrode based on the sensed electric potential. The output of the sensing electrode is coupled to a first input of an amplifier. The amplifier is configured to provide an amplified output signal representative of at least one measured biosignal based on the sensor signal and a feedback signal provided to the second input of the amplifier. A compensation signal generator is coupled between the output of the amplifier and the second input. The compensation signal generator is configured to estimate corresponding noise and provide the feedback signal to include a filtered signal representative of the estimated noise to the second input to the corresponding noise at the first input of the amplifier and mitigate saturation of the amplifier.

Time-advanced phase correction in a power amplifier circuit is disclosed. The power amplifier circuit includes a power amplifier that amplifies an analog signal, which is associated with a time-variant power envelope, based on a modulated voltage. To correct phase misalignment between the modulated voltage and the time-variant power envelope, the power amplifier circuit also includes a phase correction circuit that generates a modulated phase correction voltage based on the modulated voltage to thereby cause a phase change in the analog signal. However, the modulated phase correction voltage can lag behind the modulated voltage in time due, in part, to inherent group delay of the phase correction circuit. As such, the power amplifier circuit further includes a time advance circuit to time advance the modulated phase correction voltage to thereby realign the modulated phase correction voltage and the modulated voltage in time for an optimal phase correction in the analog signal.