A Monolithic GaN DCDC Buck Converter With an Antibootstrap Level Shifter for Envelope-Tracking Amplifier

DC-DC buck converters have become a key module for improving the overall efficiency of modern communication systems. This article reports a novel monolithic GaN dc-dc buck converter with an integrated power stage and driver for envelope-tracking applications. An antibootstrap level shifter with a power consumption of nearly zero is proposed for the first time to effectively reduce the driver power consumption and improve the total efficiency of the buck converter by at least 12%. The buck converter can be controlled by a signal with a swing of only 0.7V. The measured peak-power-stage efficiency and total efficiency of the fully integrated buck converter are over 92% and 84%, respectively, with an output power over 6W at 100MHz switching frequency. Moreover, the proposed GaN converter was tested as an envelope-tracking amplifier and achieved a total efficiency of 72.2% and normalized root-mean-square error of 2.7% for a 256QAM signal with a 20MHz bandwidth envelope.