The Supply Modulation Circuit for Dynamic Drain Voltage of the Sub-amplifiers in the Doherty Topology

In this study, the supply modulation circuit for the sub-amplifiers of the Doherty topology is described, designed, and measured. Doherty power amplifiers (PAs) assume different topologies to increase back-off power and efficiency values. However, their main concern is not about increasing the low-power region efficiency of the PA. Rather, they focus on the region between the peak power and the maximum back-off efficiency points. In this paper, a supply modulation circuit is designed and measured so that the low-power region efficiency of the Doherty PA is increased substantially by creating multiple maximum back-off efficiency points at different input power levels through adjusting the voltage supply of the PA.