PRESERVING LINEARITY OF AN ISOLATOR-FREE POWER AMPLIFIER BY DYNAMICALLY SWITCHING ACTIVE DEVICES

摘要

An amplifier circuit (100) includes a driver stage (120) with active devices (140) for pre-amplification and output of a pre-amplified signal; and an output stage (160) with active devices (180) for further amplification of the pre-amplified signal and output of an amplified signal. A detector (190) measures levels of forward and reflected parts of the amplified signal, and a control circuit (145) independently and selectively controls turning on and off of the active devices (140, 180) of the driver and output stages (120, 160) as a function of the levels of the forward and reflected signals to substantially maintain linearity of the amplifier circuit (100) with load variations.