Wide dyanmic range 2^nd order nested envelope tracking power amplifier with GaN modulator

Abstract

In this paper, a wideband envelope tracking base-station power amplifier with a 2 nd order nested scheme utilizing GaN devices for both linear and current source array was presented, which boosts envelope tracking power amplifier efficiency over wide dynamic range. Tuneable peak efficiency points in the 1 st order nested structure make a flexible efficiency adaptation for various wideband modulated signal besides efficiency boosting. Further, the 2 nd order nested scheme was proposed to enhance power saving mode for base station, e.g. LTE/LTE-A, reducing the OPEX by lower power operation according various traffic profiles.

Demystifying Envelope Tracking: Use for High-Efficiency Power Amplifiers for 4G and Beyond

“…The experimental results of prototypes were built based on a silicon metal-oxide-semiconductor field-effect transistor (MOSFET) [29] and a gallium nitride (GaN) MOSFET [48], as shown in Figure 11. By means of the multinested or high-order nested scheme, which combines "fast and slow" nested ET [31] at the same time, the instantaneous supply voltages to RF PA are not only correlated with the instantaneous envelope shape but they also track the average power of long-term RF levels for power saving. Therefore, the average efficiency boosting capability of the multinested technique enhances the dynamic range of ET.…”