US Patent 7509102 DAC based switching power amplifier

A power amplifier for use in a transmitter includes a first transistor having an input, a first node and a second node, a second transistor having an input, a first node and a second node and a digital to analog conversion module. The input of the first transistor is operably coupled to receive a first input, while the input of the second transistor is operably coupled to receive a second input. The second nodes of the first and second transistors provide an output of the power amplifier. The digital to analog conversion module is operably coupled to control current through the first and second transistors based on at least one of a power control signal and an amplitude modulation control signal.