Apparatus and methods for calibration of envelope trackers

摘要

Apparatus and methods for calibration of envelope trackers are provided. In one embodiment, a power amplifier system includes a VGA that amplifies an RF input signal to generate an amplified RF input signal, a power amplifier that amplifies the amplified RF input signal to generate an RF output signal, and an envelope tracker that generates a supply voltage for the power amplifier. The envelope tracker includes a scaling module that generates a scaled envelope signal based on a power control level (PCL) signal and an envelope signal that changes in relation to an envelope of the RF input signal. The envelope tracker further includes a calibration module that controls an amount of scaling of the scaled envelope signal based on calibration data to compensate for an envelope amplitude misalignment of the envelope tracker. The envelope tracker controls the voltage level of the supply voltage based on the scaled envelope signal.

主权项

1. A power amplifier system comprising:
a variable gain amplifier configured to amplify a radio frequency input signal to generate an amplified radio frequency input signal, the variable gain amplifier having a variable gain that is controllable by a gain control level signal; a power amplifier configured to amplify the amplified radio frequency input signal to generate a radio frequency output signal, the power amplifier configured to receive power from a supply voltage; and an envelope tracker configured to generate the supply voltage, the envelope tracker including a scaling module configured to generate a scaled envelope signal based on a power control level signal and an envelope signal that changes in relation to an envelope of the radio frequency input signal, the envelope tracker further including a calibration module configured to control an amount of scaling of the scaled envelope signal based on calibration data to compensate for an envelope amplitude misalignment of the envelope tracker, the envelope tracker further configured to control a voltage level of the supply voltage based on the scaled envelope signal.