319 / 2017-12-08 17:25:08

Design of a Four-Phase Interleaved Buck Converter for Envelope Tracking Application Based on GaN HEMTs

Envelope tracking,GaN HEMT,modulation strategy,high power level

全体主题 > Hard-switched and soft-switched applications

Envelope tracking (ET) is a crucial technology which is aimed to improve the efficiency of ratio frequency power amplification (RFPA) system. Benefitting from the excellent switching performance of GaN HEMTs, envelope tracking power amplifiers (ETPAs) are tending to higher bandwidth and larger power. This paper develops a four-phase interleaved buck converter operating as ETPA. Diffient carrier phase shift modulation strategies based on diffident carrier waveforms and PWM sampling methods are investigated in detail and the optimal one is choosen. A pulse width compensation method is utilized to achieve higher tracking precision and reduce the amplitude of harmonic components. Moreover, a half-bridge circuit cell based on GaN HEMTs with themal design is introduced. Finally, a prototype with peak power up to 500W and bandwith up to 200kHz is developed to verify the proposed method and anlysis.