A Tuning Technique for Temperature and Process Variation Compensation of Power Amplifiers with Digital Predistortion

Radio frequency (RF) power amplifiers (PAs) are the most power consuming and inefficient devices in RF transceiver systems and are often integrated with performance enhancement techniques such as digital predistortion (DPD). However, the performance of the integrated system (PA with DPD) is significantly impacted by temperature drift and process variations and thus it is essential to have a tuning mechanism that compensates for these variations. This paper presents the idea for a novel tuning technique that incorporates a digital-to-analog converter (DAC) in the integrated system (PA with DPD) to utilize the error signal generated by the digital predistortion technique to automatically tune the power amplifier's bias voltage for optimal performance. To evaluate the proposed tuning mechanism, simulation results from a closed-loop system consisting of an inverted Doherty power amplifier with digital predistortion integrated are presented.