APPARATUS AND METHODS FOR PHASE COMPENSATION IN POWER AMPLIFIERS

摘要

Apparatus and methods for phase compensation in power amplifiers are disclosed herein. In certain implementations, a power amplifier includes an input stage, an output stage, an envelope tracker, and a compensation circuit. The input and output stages are cascaded and amplify an input RF signal to generate an amplified output RF signal. The envelope tracker generates a power amplifier supply voltage for at least the output stage based on an envelope of the input RF signal. The compensation circuit compensates for changes in input impedance of the output stage associated with changes in the voltage level of the power amplifier supply voltage. By including the compensation circuit, a variation in the power amplifier's phase delay versus input power can be reduced, thereby leading to an improvement in the power amplifier's phase distortion (AM/PM).

主权项

1. A method of phase compensation in a power amplifier system, the method comprising:
amplifying an input radio frequency (RF) signal to generate a first amplified RF signal using a first amplification stage of a power amplifier; generating a power amplifier supply voltage using an envelope tracker; controlling a voltage level of the power amplifier supply voltage based on an envelope of the input RF signal using the envelope tracker; powering a second amplification stage of the power amplifier using the power amplifier supply voltage from the envelope tracker; amplifying the first amplified RF signal to generate a second amplified signal using the second amplification stage; and compensating for a variation in an input impedance of the second amplification stage associated with changes in the voltage level of the power amplifier supply voltage using a compensation circuit.