Freescale Semiconductor,inc.

Pravinkumar Premakanthan

Mahibur Rahman

Jorge Ivonnet

Methods and apparatus are provided for gain and phase compensation in a radio frequency (RF) transmitter (). The RF transmitter () has at least one power amplifier (PA) () for providing a transmitted signal having a signal power therefrom. An RF power detector () is coupled to the at least one PA () for detecting the signal power of the transmitted signal and an analog to digital (A/D) converter () is coupled to the RF power detector (). A hysteresis unit () is coupled to the A/D converter () for generating a pulse () in response to a power threshold being crossed and a load switch control unit () is coupled to the hysteresis unit and the at least one power amplifier for providing gain and phase compensation in response to the pulse.

Dynamic gain and phase compensation for power amplifier load switching

An adaptive closed loop transmit power control system which does not require extensive factory calibration of power control loop bandwidths and feedback detect path gain settings over the power transition ranges, frequency bands of operation, temperature, and supply voltage is disclosed. The system automatically compensates for any gain or slope variations in the analog feedforward and feedback paths to maintain system stability and meet performance specifications. The system achieves this by using an adaptive digital signal processing (DSP) system architecture within the feedback path of this closed loop power control system. The system eliminates the need for extensive factory calibration of such parameters as loop bandwidths and feedback detect path gain settings over power transition ranges, frequency bands of operation, temperature, and supply voltage.

Adaptive transmit power control system

A method () and apparatus () facilitate closed loop transmit power control in a power control loop at and during a transition from one transmit power level to another transmit power level in a transmitter. The apparatus includes a reference path () configured to provide a reference signal () and a gain compensation signal (), a detect path () configured to process, in accordance with the gain compensation signal, a detected signal corresponding to a power level to provide a gain compensated detected signal; and a power control path () configured to generate a power control value in accordance with the reference signal, the gain compensated detected signal, and a loop compensation factor associated with the gain compensation signal where the power control value is suitable for setting the power level for the transmission.

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Delray Beach, FL, United States of America

Pravinkumar Premakanthan