Embodiments of the invention may provide for enhancement systems and methods for a power amplifier output control system. In an example embodiment, driver amplifier control may be provided in conjunction with power amplifier control to improve the power efficiency and/or dynamic range of the transmitter...http://www.google.com/patents/US7768353?utm_source=gb-gplus-sharePatent US7768353 - Systems and methods for switching mode power amplifier control
