Patent ID: 8461931

Claim:
A power amplifier circuit for amplifying at least one radio frequency (RF) signal applied to an output load, the power amplifier circuit operating at a plurality of frequency bands, the power amplifier circuit comprising: a wideband power amplifier configured to have a constant output impedance, wherein the constant output impedance of the wideband power amplifier is equal to a load impedance of the output load; a power controller configured for changing a bias voltage provided by a power supply to the wideband power amplifier, wherein the output impedance of the wideband power amplifier remains equal to the load impedance of the output load when the power controller changes the bias voltage from a first voltage level to a second voltage level; and a secondary power amplifier configured for amplifying a low power radio frequency signal, the secondary power amplifier by-passing the wideband power amplifier when the low power radio frequency signal is to be amplified.