RF Power Amplifier Controller Circuit Including Calibrated Phase Control Loop

A method of controlling a power amplifier receiving and amplifying an RF input signal to generate an RF output signal, the method comprising the steps of:

• comparing an amplitude of the RF input signal with an attenuated amplitude of the RF output signal to generate an amplitude correction signal indicative of an amplitude difference between the amplitude of the RF input signal and the attenuated amplitude of the RF output signal;
• adjusting a supply voltage or bias to the power amplifier based upon the amplitude correction signal;
• comparing a phase of the RF input signal with a phase of the RF output signal to generate a phase error signal;
• filtering the phase error signal to allow frequency components of the phase error signal higher than a predetermined frequency to pass;
• and
• shifting the phase of the input signal to the power amplifier based upon the passed frequency components of the phase error signal.

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:
• one or more variable phase delays introducing a phase delay in the phase control loop to adjust a phase difference between phases of the RF input signal and the RF output signal;
• 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 the phase difference between phases of the RF input signal and the RF output signal;
• and
• a phase shifter coupled to the phase comparator and 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.

A method of controlling a power amplifier receiving and amplifying a radio frequency (RF) input signal to generate an RF output signal, the method comprising the steps of:

• comparing an amplitude of the RF input signal with an attenuated amplitude of the RF output signal to generate an amplitude correction signal indicative of an amplitude difference between the amplitude of the RF input signal and the attenuated amplitude of the RF output signal;
• adjusting a supply voltage or bias to the power amplifier based upon the amplitude correction signal;
• introducing a relative phase delay between the RF input signal and the RF output signal to adjust a phase difference between phases of the RF input signal and the RF output signal to be within a predetermined phase range;
• comparing a phase of the RF input signal with a phase of the RF output signal with the introduced relative phase delay to generate a phase error signal;
• and
• shifting the phase of the RF input signal to the power amplifier based upon the phase error signal.