Systems, methods, and circuitries are provided for generating a power amplifier supply voltage based on a target envelope signal for a radio frequency (RF) transmit signal. An envelope tracking system includes a first selector circuitry and predistortion circuitry. The first selector circuitry is disposed in a selector module and is configured to input a plurality of voltages conducted on a first plurality of power lanes, wherein the first plurality of power lanes is part of a power distribution network; select a voltage from the plurality of voltages based on the target envelope signal; and provide the selected voltage to a supply lane connected to an input of the power amplifier that amplifies the RF transmit signal. The predistortion circuitry is configured to modify the RF transmit signal based on a selected power lane of the first plurality of power lanes that conducts the selected voltage.

Apparatus and methods for power amplifiers with positive envelope feedback are provided herein. In certain implementations, a power amplifier system includes a power amplification stage that amplifies a radio frequency signal, at least one envelope detector that generates one or more detection signals indicating an output signal envelope of the power amplification stage, and a wideband feedback circuit that provides positive envelope feedback to a bias of the power amplification stage based on the one or more detection signals. The power amplifier system further includes a supply modulator that controls a voltage level of a supply voltage of the power amplification stage based on the one or more detection signals such that the supply voltage is modulated with the output signal envelope through positive envelope feedback.

A tracker circuit configured to provide a variable supply voltage to a power amplifier (PA) circuit is disclosed. The tracker circuit includes a state machine circuit comprising a plurality of states mapped in accordance with transitions associated with a mapping scheme. In some embodiments, the plurality of states of the state machine circuit identify one or more operational modes associated with the tracker circuit, wherein at least one operational mode comprises one or more voltage levels respectively associated therewith. In some embodiments, the one or more operational modes includes at least two active operational modes. In some embodiments, a transition between the one or more operational modes of the tracker circuit is controlled by a digital selection signal received from a digital communication interface associated therewith.

An apparatus includes an envelope detecting unit for detecting an envelope of a signal to be amplified, and a variable power supply applies, to an output terminal of a carrier amplifier, a voltage increased with increase in the envelope detected by the envelope detecting unit. As a result, highly efficient operation can be implemented without including a phase shifter including a quarter wavelength line or the like.

An H-bridge power amplifier arrangement with envelope tracking is disclosed. The power amplifier arrangement comprises four elements form the four corner bars of a first H-bridge structure with a load formed as the cross bar of the first H-bridge structure. The power amplifier arrangement further comprises a rectifier circuit coupled between the first positive power supply and the third positive power supply configured to recycle the sinking envelope current.

An envelope tracking supply modulator for a power amplifier is disclosed. The envelope tracking supply modulator comprises a multilevel push-pull converter. The multilevel push-pull converter comprises a control logic configured to generate a first and second control signals based on an envelope reference signal; a source multilevel converter configured to receive the first control signal and generate a source multilevel power supply signal; a sink multilevel converter configured to receive the second control signal and generate a sink multilevel power supply signal. The envelope tracking supply modulator further comprises a power recycling supply coupled to the sink multilevel converter; a low-pass filter coupled to outputs of the source and sink multilevel converters to filter the power supply signals generated from the source and sink multilevel converters.

Aspects of an envelope tracking operation are described. In some aspects, as part of the envelope tracking operation, a device determines a change in a first set of power amplifier (PA) operating conditions, corresponding to a first look up table (LUT), the first LUT defined by a first LUT equation and a maximum supply voltage value. In some aspects, the device autonomously generates a second LUT equation to define a second LUT, having a second set of corresponding PA operating conditions. In some aspects, the device selects values from the first LUT equation, estimates a slope of the second LUT equation, determines an intercept with a maximum power value, and adjusts a supply voltage input for the PA to a supply voltage according to the maximum power value.

A feedback-based power supply for a radio-frequency power amplifier includes: a linear amplification unit, a first controlling unit, a first driving unit, a first feeding-back unit and a superimposing unit, and the first controlling unit obtains a feedback signal of a change rate of an electrical signal of a supply voltage end of the radio-frequency power amplifier through the first feeding-back unit and outputs a first control signal to enable the power supply to work in any one of the following modes: a constant on time control mode having a constant on time and a constant off time control mode having a constant off time; the first driving unit is configured to connect an output end of the first controlling unit and provide a first electrical signal based on the first control signal.

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.

Example signal processing apparatus and signal processing methods are described. One example signal processing apparatus includes a signal matching circuit, a first signal processing branch, and a second signal processing branch. An output end of the signal matching circuit is separately coupled to an input end of the first signal processing branch and an input end of the second signal processing branch, and an output end of the first signal processing branch is coupled to the input end of the second signal processing branch.