An RF PA is designed to operate efficiently for average powers when biased at the system supply voltage, and uses an envelope tracking power supply to boost the bias voltage to maintain good efficiency at higher powers. As a result, for a majority of the time when transmitting average power signals, the RF PA bias voltage is the system-wide supply voltage (e.g. 3.4V in cell phones), which eliminates the need for stepping down voltages. The bias voltage is boosted during the less frequent times when higher power is needed. As a result, only a boost type of DC voltage converter is needed. The efficiency of the RF PA is therefore increased because voltage conversion is required less frequently and only when higher power RF signals are transmitted.