Method of power amplifier calibration for an envelope tracking system

摘要

A method for power amplifier (PA) calibration for an envelope tracking system of a wireless device is disclosed. The method involves measuring an output power of a PA that is a part under test (PUT) at a predetermined input power. Another step includes calculating a gain equal to the output power of the PA divided by the predetermined input power. A next step involves calculating a gain correction by subtracting the calculated gain from a desired gain. Other steps include determining an expected supply voltage for the PA at the desired gain using the gain correction applied to a nominal curve of gain versus PA supply voltage, and then storing the expected supply voltage for the PA versus input power in memory.

主权项

1. A method for power amplifier (PA) calibration for an envelope tracking system of a wireless device comprising:
measuring an output power of a PA that is a part under test (PUT) at a predetermined input power; calculating a gain equal to the output power of the PA divided by the predetermined input power; calculating a gain correction by subtracting the calculated gain from a desired gain; determining an expected supply voltage for the PA at the desired gain using the gain correction applied to a nominal curve of gain versus PA supply voltage; determining a first difference between a measured PA supply voltage and a nominal PA supply voltage value for a first input power; determining a second difference between a measured PA supply voltage and a nominal PA supply voltage value for a second input power; calculating a slope and an intercept for a line that that yields calibration values as a function of PA supply voltage using the first difference, the second difference, the first input power, and the second input power; and storing the calibration values for PA supply voltage versus input power in a look up table memory that is accessible by the wireless device.