Integrated DC-DC converter design for improved WCDMA power amplifier efficiency in SiGe BiCMOS technology

We present a DC-DC converter design for on-chip integration with a WCDMA power amplifier to provide supply voltage modulation and efficiency enhancement. It operates from a 3.3 V supply using 0.35 /spl mu/m 'high-breakdown' CMOS transistors available in IBM's SiGe BiCMOS 6H:P process. Five selectable output voltage levels are available ranging from 1.3 V to 3.3 V. The converter is optimized for operation at 88.7 MHz. Simulation results show an average efficiency of 78.8% over the power amplifier operating conditions and a peak enabled efficiency of 86%. CCM-DCM mode switching and transistor width switching are used to minimize losses at the different output voltage and current load levels.