Quad LINC transmitter with switchable Chireix amplifiers

A circuit for a transmitter comprising:

• an in-phase branch of components;
• and a quadrature branch of components, wherein the in-phase branch is configured to receive first and second in-phase constant baseband envelope signals and a first phase signal, and comprises:
• a load;
• a first Chireix compensation circuit comprising:
• a first power amplifier,
• a second power amplifier,
• a first Chireix inductor, and
• a first Chireix capacitor, wherein an output of the first Chireix compensation circuit is coupled to the load;
• a second Chireix compensation circuit comprising:
• a third power amplifier,
• a fourth power amplifier,
• a second Chireix inductor, and
• a second Chireix capacitor, wherein an output of the second Chireix compensation circuit is coupled to the load, and the outputs of the first and second Chireix compensation circuits are coupled to the load in reverse bias relative to each other;
• first switches configured to couple the first in-phase constant baseband envelope signal and second in-phase constant baseband envelope signal to either the first or second Chireix compensation circuits in accordance with the first phase signal, wherein the quadrature branch is configured to receive first and second quadrature constant baseband envelope signals and a second phase signal, and comprises:
• a quadrature branch load;
• a third Chireix compensation circuit comprising:
• a fifth power amplifier,
• a sixth power amplifier,
• a third Chireix inductor, and
• a third Chireix capacitor, wherein an output of the third Chireix compensation circuit is coupled to the quadrature branch load;
• and
• a fourth Chireix compensation circuit comprising:
• a seventh power amplifier,
• an eighth power amplifier,
• a fourth Chireix inductor, and
• a fourth Chireix capacitor, wherein an output of the fourth Chireix compensation circuit is coupled to the quadrature branch load, the outputs of the third and fourth Chireix compensation circuits are coupled to the quadrature branch load in reverse bias relative to each other;
• and
• second switches configured to couple the first quadrature constant baseband envelope signal and second quadrature constant baseband envelope signal to either the third or fourth Chireix compensation circuits in accordance with the second phase signal.