Patent ID: 9106293
Filing Date: 2015-08-11
Classification: H03F,H04B

Abstract:
1. A method for delay calibration in an envelope tracking power amplifier system, the method comprising: generating an envelope tracking signal tracking a detected amplitude of an input signal to the power amplifier; generating a supply voltage to the power amplifier, wherein the supply voltage comprises a substantially constant voltage when an input voltage of the input signal is below an amplitude threshold and wherein the supply voltage comprises a dynamically varying envelope tracking voltage based on the envelope tracking signal when the input voltage is above the amplitude threshold; determining a first delay between the input signal and an output signal of the power amplifier based on portions of the input signal and the output signal captured when the input signal is below the amplitude threshold; determining a second delay between the input signal and the output signal based on portions of the input signal and the output signal captured when the input signal is above the amplitude threshold; configuring a delay block to compensate for a determined delay mismatch between the input signal to the power amplifier and the supply voltage, the determined delay mismatch based on a difference between the first delay and the second delay; and amplifying, by a power amplifier, the input signal to generate an output signal, the power amplifier powered from the supply voltage.