Two stage doherty amplifier

A Doherty power amplifier comprising:

• a first power amplifier adapted to receive an input signal and adapted to provide a first output signal which is phase shifted with respect the input signal;
• a second power amplifier, adapted to receive a phase shifted input signal and adapted to provide a second output signal;
• characterized in that each one of the first and the second power amplifiers comprises
• a first driver power amplifier comprising a first gate input and a first drain output;
• the first driver power amplifier being coupled to a first output power amplifier comprising a second gate input and a second drain output;
• the first gate input and the second gate input being adapted to receive a control signal, the control signal being obtained after an envelope detection provided by an envelope detector coupled to the input signal.

A method of operating a Doherty power amplifier comprising steps of:

• receiving an input signal by a first power amplifier and providing a first output signal which is phase shifted with respect to the input signal;
• receiving a phase shifted input signal by a second power amplifier, and providing a second output signal;
• characterized in that the method further comprises steps of
• receiving a control signal representing a signal that would be obtained by an envelope detection of the input signal;
• applying the control signal to a circuit comprising a first driver power amplifier comprising a first gate input and a first drain output, the first driver power amplifier being coupled to a first output power amplifier comprising a second gate input and a second drain output, the first gate input and the second gate input being adapted to receive a control signal, the control signal being obtained after an envelope detection provided by an envelope detector coupled to the input signal.