Patent attributes
An RF power amplifier has a final-stage amplifier stage which generates an RF transmit output signal, a signal detector which detects an RF transmit output level, a first detector, a second detector and a control circuit. The final-stage amplifier stage includes a transistor and a load element and performs saturation type nonlinear amplification and non-saturation type linear amplification. The first detector and the control circuit maintain the RF transmit output signal approximately constant with respect to a variation in load at an antenna at the saturation type nonlinear amplification. The second detector and the control circuit reduce an increase in the output voltage of the final stage transistor with respect to an overload state of the antenna at the non-saturation type linear amplification.
