Operating Modes of Dynamic Power Supply Transmitter Amplifiers

Any amplifier operated with a varying supply voltage is actually a three-port circuit, having two inputs and one output. When an amplifier is characterized as a three-port for dynamic supply voltage operation, three separate operating modes appear: linear L-mode and the two nonlinear modes C-mode and P-mode. Each of these modes, along with their relationships and differences, are identified, characterized, and discussed. Relations of these modes to the dynamic power supply transmitter techniques of envelope tracking and/or direct polar are presented. Measurements are reported that provide experimental verification for these amplifier operating modes.