Multi-branch outphasing system and method

A multi-level, multi-branch outphasing amplifier comprising:

• a first branch group circuit including:
• a first branch circuit including a first activation circuit and a first power amplifier, the first activation circuit coupled to receive an RF first input signal and a first control signal, the first activation circuit configured to selectively enable and disable the RF first input signal from being transmitted to the first power amplifier responsive to the first control signal;
• and
• a second branch circuit including a second activation circuit an a second power amplifier, the second activation circuit coupled to receive the RF first input signal and a second control signal, the second activation circuit configured to selectively enable and disable the RF first input signal from being transmitted to the second power amplifier responsive to the second control signal;
• a second branch group circuit including:
• a third branch circuit including a third activation circuit and a third power amplifier, the third activation circuit coupled to receive an RF second input signal and a third control signal, the third activation circuit configured to selectively enable and disable the RF second input signal from being transmitted to the third power amplifier responsive to the third control signal;
• and
• a fourth branch circuit including a fourth activation circuit and a fourth power amplifier, the fourth activation circuit coupled to receive the RF second input signal and a fourth control signal, the fourth activation circuit configured to selectively enable and disable the RF second input signal from being transmitted to the fourth power amplifier responsive to the fourth control signal;
• combiner circuitry for combining output signals of the first, second, third and fourth power amplifiers and producing an output signal across a load;
• and
• a single constant-value voltage supply for supplying power to the first branch group circuit and to the second branch group circuit;
• wherein a number of enabled RF input signals in the first branch group circuit and a number of enabled RF input signals in the second branch group circuit are selected to be the same or different, depending on a power demand of the load or on a backoff load current.