Linearizing CMOS Switching Power Amplifiers Using Supply Regulators

In high-speed communications systems, the power amplifier (PA) is the dominant source of power consumption from the battery and, thus, one of the main limitations in increased mobility. Switching PAs are more efficient than their linear counterparts and, thus, demand less power from the battery; however, they do not have sensitivity to the amplitude variations seen in nonconstant-envelope modulation. This brief discusses supply modulation, a technique that enables use of switching PAs for improved power efficiency, by providing a means of linearizing the PA.