Patent ID: 7917106

Claim:
A radio frequency (RF) power amplifier system, comprising: a power amplifier coupled to receive and amplify an RF input signal to generate an RF output signal; and a power amplifier controller including: an amplitude control loop determining an amplitude correction signal indicative of an amplitude difference between an amplitude of the RF input signal and an attenuated amplitude of the RF output signal and adjusting a supply voltage or bias to the power amplifier based upon the amplitude correction signal; and a phase control loop comprising: a phase comparator comparing the phase of the RF input signal with the phase of the RF output signal to generate a phase error signal indicative of a phase difference between phases of the RF input signal and the RF output signal; a phase shifter coupled to the power amplifier, the phase shifter shifting the phase of the RF input signal to the power amplifier based upon the phase error signal to reduce phase distortion generated by the power amplifier; and a low frequency blocking module coupled between the phase comparator and the phase shifter, the low frequency blocking module allowing frequency components of the phase error signal higher than a predetermined frequency to be passed from the phase comparator to the phase shifter, wherein the amplitude control loop comprises: an amplitude comparator comparing the amplitude of the RF input signal with the attenuated amplitude of the RF output signal to generate the amplitude correction signal; a power supply coupled to receive the amplitude correction signal and generating the adjusted supply voltage provided to the power amplifier based upon the amplitude correction signal; a gain control module coupled to the amplitude comparator and receiving the amplitude correction signal to generate a gain control signal; and a variable gain amplifier coupled to the gain control module, the variable gain amplifier adjusting the amplitude of the RF input signal to the power amplifier based upon the gain control signal, and wherein the power supply comprises: a first power supply with a first efficiency, the first power supply coupled to the amplitude comparator and receiving a first portion of the amplitude correction signal in a first frequency range and generating a first adjusted supply output based upon the first portion of the amplitude correction signal; and a second power supply with a second efficiency higher than the first efficiency, the second power supply coupled to the amplitude comparator and receiving a second portion of the amplitude correction signal in a second frequency range lower than the first frequency range and generating a second adjusted supply output based upon the second portion of the amplitude correction signal, the adjusted supply voltage including a combination of the first adjusted supply output and the second adjusted supply output.