Method and apparatus for an enhanced efficiency power amplifier

A method for amplifying an input signal comprising the steps of:

• sampling an input signal having an input amplitude and an input phase angle value;
• comparing the input amplitude to a threshold value;
• determining an outphasing angle value based on the input amplitude;
• generating a first drive signal having a first amplitude and a first phase angle value that is substantially the input phase angle value plus at least a portion of the outphasing angle value;
• generating a second drive signal having a second amplitude and a second phase angle value that is substantially the input phase angle value minus at least a portion of the outphasing angle value;
• generating at least a third drive signal having a third amplitude and a third phase angle value;
• amplifying the at least first, second and third drive signals;
• and
• combining the amplified first, second and third drive signals to generate an output signal, wherein when the input amplitude is less than the threshold value the amplified third drive signal has substantially a zero amplitude, and wherein when the input amplitude is at least equal to the threshold value the outphasing angle value is substantially equal to a constant value.