Apple Inc.
Method and apparatus for digital envelope tracking with dynamically changing voltage levels for power amplifier

Abstract:

A device for digital envelope tracking with dynamically changing voltage levels for a radio frequency (RF) power amplifier is disclosed. A power management unit generates a set of supply voltages for a power amplifier based on a control signal. A setpoint generator in the power management integrated circuit gradually increases or decreases a target voltage such that the set of supply voltages output from the voltage converter gradually increase or decrease in response to a gradual transition of the target voltage. A transceiver includes digital models for replicating a behavior of the setpoint generator and a voltage regulator in the voltage converter such that a signal pre-distortion unit may use an instantaneous voltage level for signal predistortion.