Apparatus and methods for bias switching of power amplifiers are provided herein. In certain configurations, a power amplifier system includes a power amplifier that provides amplification to a radio frequency (RF) signal, a power management circuit that controls a voltage level of a supply voltage of the power amplifier, and a bias control circuit that biases the power amplifier. The power management circuit is operable in multiple supply control modes, such as an average power tracking (APT) mode and an envelope tracking (ET) mode. The bias control circuit is configured to switch a bias of the power amplifier based on the supply control mode of the power management circuit.

A radio frequency transmitter includes N transmit channels, where each transmit channel includes one nonlinear module, a primary correction circuit, coupled to each of N nonlinear modules that correspond to the N transmit channels, and configured to provide a primary correction signal for the N nonlinear modules, and N secondary correction circuits, where the N secondary correction circuits are coupled to the N nonlinear modules respectively, and each secondary correction circuit is configured to provide a secondary correction signal for a nonlinear module coupled to the secondary correction circuit.

The present disclosure provides an amplifier circuit that includes one or more amplifier stages, each of the one or more amplifier stages including a complementary transistor configuration. The complementary transistor configuration includes an NMOS transistor and a PMOS transistor. The NMOS transistor is electrically coupled in parallel to the PMOS transistor. The amplifier circuit further includes an output amplifier stage electrically coupled to an output of the one or more amplifier stages, the output amplifier stage including a non-complementary transistor configuration including one or more NMOS transistors or PMOS transistors.

The present disclosure provides a radio frequency (RF) front-end of a low power consumption and fully automatic adjustable broadband receiver, including a low-noise amplification module, amplifying an broadband single-ended RF signal, and converting it into differential current signal; a local oscillator, generating a local oscillator signal; an quadrature mixer, quadraturely mixing the differential current signal and the local oscillator signal to generate intermediate frequency differential current signals; a transimpedance amplifier, converting the intermediate frequency differential current signal into an intermediate frequency differential voltage signal; an IIP2 calibration module, reducing the IIP2 effect of the RF front end; a received signal strength indicator module, sending the first amplification factor control signal and the differential mismatch control signal to the low noise amplification module, and sending the second amplification factor control signal to the transimpedance amplifier, thereby making the intermediate frequency differential voltage signals meet the requirements of the amplitude and mismatch.

A digital power amplifier comprising two or more individually activatable amplifiers. The outputs of the amplifiers are connected causing an activated amplifier of the two or more amplifiers to load modulate another activated amplifier of the two or more amplifiers.

An envelope tracking system having delay compensation circuitry is disclosed. The envelope tracking system includes transmit circuitry configured to receive an input transmit signal, a gain control signal, and delay compensation values. The envelope tracking system is further configured to generate an envelope tracking signal based on the input transmit signal, the gain control signal, and the delay compensation values, and generate an output transmit signal based on the input transmit signal. The envelope tracking system also includes a power amplifier configured to generate an amplified transmit signal based on the output transmit signal and an operating voltage. The envelope tracking system further includes an envelope tracking integrated circuit configured to control the operating voltage based on the envelope tracking signal. The delay compensation circuitry is configured to generate the delay compensation values based on a peak-to-average ratio of a given modulation type and the gain control signal.

A transmitter includes a processing circuit to generate I level data and Q level data that, when respectively converted to I baseband input and Q baseband input, cause a carrier signal modulated by the I baseband input and the Q baseband input to have a desired edge shape in the time domain. The edge shape includes a low portion, a high portion, and an edge portion between the low portion and the high portion. The edge portion has a desired edge time compatible with the frequency of the carrier signal. The transmitter further includes a digital-to-analog converter (DAC) to convert the I level data to the I baseband input and the Q level data to the Q baseband input, and an in-phase and quadrature (I/Q) modulator to perform I/Q modulation of the carrier signal according to the I baseband input and the Q baseband input.

The present disclosure provides a radio frequency (RF) front-end of a low power consumption and fully automatic adjustable broadband receiver, including a low-noise amplification module, amplifying an broadband single-ended RF signal, and converting it into differential current signal; a local oscillator, generating a local oscillator signal; an quadrature mixer, quadraturely mixing the differential current signal and the local oscillator signal to generate intermediate frequency differential current signals; a transimpedance amplifier, converting the intermediate frequency differential current signal into an intermediate frequency differential voltage signal; an IIP2 calibration module, reducing the IIP2 effect of the RF front end; a received signal strength indicator module, sending the first amplification factor control signal and the differential mismatch control signal to the low noise amplification module, and sending the second amplification factor control signal to the transimpedance amplifier, thereby making the intermediate frequency differential voltage signals meet the requirements of the amplitude and mismatch.

A vector distribution method for operation of a power amplifier of a wireless transmitter including receiving, by a first amplifier circuit, a first input vector and a second input vector. The first input vector includes data derived from an input signal of the wireless transmitter and the second input vector includes other data derived from the input signal of the wireless transmitter. The method includes, in response to receiving the input signal, instructing the first amplifier circuit to output an output signal at a high voltage.

Methods and systems for power amplification with digital quantized power supply with multiple amplifiers are disclosed herein. In one embodiment, In one embodiment, a time-varying envelope signal is sampled, quantized and decomposed into several constituent signals that are individually amplified, and then combined to form a desired amplified version of the quantized time-varying envelope. Amplitude, phase and/or frequency characteristics of one or more of the signals and supply voltages V.sub.dd and source current of one or more amplifiers are digital controlled based on the information provided by quantization process and slow and fast power control information. Amplitude, phase and/or frequency characteristics of one or more of the constituent signals to be amplified are controlled to provide the desired amplitude, phase, frequency, and/or spectral characteristics of the desired quantized version of the time-varying envelope signal.