Patent attributes
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.
