Abstract: A radio frequency (“RF”) power amplifier circuit as described herein is configured to detect and measure an output load mismatch and to adjust the operating characteristics of the RF power amplifier to reduce output signal distortion. The circuit includes a directional RF signal coupler that obtains a coupled reflected RF signal that is indicative of the output load mismatch. The coupled reflected RF signal is processed to generate one or more bias control signals for the RF power amplifier. In operation, a mismatch condition will result in a measurable coupled reflected RF signal and a corresponding reduction in output power from the RF power amplifier. Ultimately, the output power control mechanism strives to maintain the RF power amplifier within a linear operating range.

Abstract: An amplifier circuit (10) and a method for increasing linearity of the amplifier circuit. The amplifier circuit (10) has a limiter (13) that generates a phase modulated signal (30) in accordance with a phase modulated component (22) of an RF input signal (20). The amplifier circuit (10) also has an envelope detector (16) that generates an envelope signal (40) in accordance with the amplitude modulated component (21) of the RF input signal (20). A delay compensation circuit (17) receives the envelope signal (40) and generates a lead phase envelope signal (50) and an envelope amplifier (18) receives the lead phase envelope signal (50) and generates a bias signal. An RF amplifier (14) amplifies the phase modulated signal (30) in accordance with the bias signal.