Digital Control of Power Amplifiers for Wireless Communications

The advance of CMOS-based digital circuits enables new strategies for optimisation of wireless transmitters. Co-design of DSP algorithms and power amplifier characteristics can lead to improved efficiency and linearity through a variety of strategies, including: a) DSP control over bias conditions, particularly the power supply voltage; b) predistortion, in simple amplifiers, and in compound architectures such as LINC and Doherty amplifiers; and c) DSP generation of digital input signals for switching amplifiers. We envision for the future a generation of "smart power amplifiers" in which DSP optimization of amplifier parameters is carried out for changing environments.