Ultra-fast Voltage Modulator for High-efficiency Radio Frequency Power Amplifiers

This paper presents a compact and ultra-fast voltage modulator for high efficiency radio frequency power amplifiers. A single DC/DC converter with multiple fast switched output stage is introduced, a unique nonlinear control scheme is developed to adapt the dynamical state variables and regulate output levels. Fast transient response and high efficiency is archived as close to the constant output DC/DC converter. A 4-level fast voltage modulator is built with voltage transition speed in tens of nanoseconds and efficiency up to 95%.