Wireless-Modem Power for Hand-Held Devices

Abstract: Thanks to lackluster efficiency in currently available RF power amplifiers (PAs), the addition of wireless communications to hand-held computing devices entails unusual power-management techniques. Some communications protocols allow burst-transmission techniques and shutdown when not transmitting (duty-cycle control), but during a transmission the typical PA efficiency is no greater than 40% to 60%. In contrast, efficiency for the main power supply in a hand-held device is typically 90% to 95%.