Digital Bias Adjustment in a Variable Supply Radio Frequency Power Amplifier

A radio frequency (RF) power amplifier comprising:

• an RF amplifier stage coupled to receive an RF input signal and supply an RF output signal, the RF amplifier stage including one or more active gain elements to amplify the RF input signal, the RF amplifier stage being further coupled to a variable supply voltage and to one or more bias signals to set a bias state for the RF amplifier stage;
• a bias circuit coupled to receive a control input specifying the bias state, the bias circuit coupled to supply the one or more bias signals to the RF amplifier stage, operation of the RF amplifier stage being varied in response to change in the bias state;
• and
• a digital control block coupled to receive a sense input representing the variable supply voltage, the digital control block operable to determine the bias state for the RF amplifier stage responsive to the sense input, the bias state varying according to the variable supply voltage, the digital control block coupled to the bias circuit to provide the control input.