Patent ID: 8076974
Filing Date: 2011-12-13
Classification: H03F

Abstract:
1. An RF power amplifier comprising: 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, wherein the final stage amplifier stage performs the saturation type nonlinear amplification and the non-saturation type linear amplification and includes: wherein an RF detection signal outputted from the signal detector is supplied to the first detector, and an output voltage of the final stage transistor is supplied to the second detector, wherein 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, and wherein 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.