US Patent 8706064 Systems and methods to adjust the bias of an amplifier

A system and method improve amplifier efficiency of operation relative to that of an amplifying transistor with a fixed bias current. A power level representing a level of transmission power from an amplifier circuit and an indicator of amplifier circuit operation are provided. The indicator is at least one of channel, channel bandwidth, out-of band spectral requirements, spectral mask requirements, error vector magnitude, modulation rate, and modulation type. The amplifying transistor is biased with a bias current that is determined based at least in part on the power level and the indication where the bias current is different for channels at an edge of a channel band than for channels nearer a center of the channel band.