PPA Linearization

摘要

A linearization circuit improves the linearity of a power amplifier based on an envelope of an input RF signal. The linearization circuit comprises an RF signal generation circuit, a replica circuit, and an adaptive amplifier. The RF signal generation circuit generates the RF signal from a phase and an amplitude of an input digital signal. The replica circuit extracts the envelope from the RF signal and generates a sensing voltage based on the extracted envelope. The adaptive amplifier generates an adaptive bias voltage for the power amplifier based on the sensing voltage, and applies the adaptive bias voltage to the power amplifier and to the replica circuit to improve the linearity of the power amplifier by regulating the power amplifier and the replica circuit according to the envelope.

主权项

1. A linearization circuit for improving linearity of a class B or class AB or class C power amplifier based on an envelope of a radio frequency (RF) signal input to the power amplifier and generated from a phase and amplitude of an input digital signal, the linearization circuit comprising:
a replica circuit configured to receive the generated RF signal and configured to extract the envelope from the RF signal, and generate a sensing voltage based on the extracted envelope; and an adaptive amplifier operatively connected to the replica circuit and the power amplifier, the adaptive amplifier configured to generate an adaptive bias voltage for the power amplifier based on the sensing voltage; wherein the adaptive amplifier applies the adaptive bias voltage to the power amplifier and to the replica circuit to improve the linearity of the power amplifier by regulating the power amplifier and the replica circuit according to the envelope; and wherein an operational point of the power amplifier is set such that an average amplifier current increases with increasing amplitude of the RF signal.