Patent ID: 6522201
Filing Date: 2003-02-18
Classification: H03G

Abstract:
An RF power amplifier operable at two output power levels comprising:a) a first signal power amplification unit having an input terminal for receiving an input signal, an output terminal for producing an amplified power output signal, and a power terminal for receiving a voltage, and b) a first load coupling the output terminal of the first signal power amplification unit to an RF output, the load having a plurality of values corresponding to a plurality of power levels including a first value for a full power output signal and a second value for a back-off power level, the second value being greater than the first value, the load value being greatest for the lowest power level, and c) a second signal power amplification unit in parallel with the first signal power amplification unit and a second load coupling the output terminal of the second signal power amplification unit to the RF output, the second load having higher impedance than the first load, and switch means for alternately connecting the first signal power amplification unit and the second signal power amplification unit to the RF output.