Envelope tracking technique for mobile handset application (Inviter Paper)

Envelope tracking technique is suitable to the transmitters for mobile handset and becomes a hot research item in recent years. In this paper, we will overview the research trends in this area. The supply modulator handles the modulated signal and the PA works only for RF amplification. Because of the separated functions, the architecture is a favored structure for multimode/multiband operation. The supply modulator is an ideal power management IC for a PA. This technique is perused to improve the efficiency at a high power level as well as at a low power level. Because of the enhanced efficiency at a low power level, the transmitter can provide good performance at a low/high mode PA for handset. These new developments of the ET technology will be introduced.