—This paper presents and compares three circuit architectures that are promising candidates to efficiently and dynamically supply GSM and EDGE RF power amplifiers in handsets. The candidate architectures include a switcher with hysteretic control, and two linear-assisted switcher configurations. The architectures have been implemented and tested by simulation in a standard 0.5µ,µ,µ,µ, 5V CMOS process. The circuits are compared in terms of efficiency and reference tracking capabilities.