High efficiency, high switching speed, AlGaAs/GaAs P-HEMT DC–DC converter for integrated power amplifier modules

摘要

This paper presents a high efficiency, high switching frequency DC–DC buck converter in AlGaAs/GaAs technology, targeting integrated power amplifier modules for wireless communications. The switch mode, inductor load DC–DC converter adopts an interleaved structure with negatively coupled inductors. Analysis of the effect of negative coupling on the steady state and transient response of the converter is given. The coupling factor is selected to achieve a maximum power efficiency under a given duty cycle with a minimum penalty on the current ripple performance. The DC–DC converter is implemented in 0.5 μm GaAs p-HEMT process and occupies 2 × 2.1 mm2 without the output network. An 8.7 nH filter inductor is implemented in 65 μm thick top copper metal layer, and flip chip bonded to the DC–DC converter board. The integrated inductor achieves a quality factor of 26 at 150 MHz. The proposed converter converts 4.5 V input to 3.3 V output for 1 A load current under 150 MHz switching frequency with a measured power efficiency of 84%, which is one of the highest efficiencies reported to date for similar current/voltage ratings.