A highly efficient GHz switching GaN-based synchronous buck converter module. Issue 10 (23rd December 2020)

• Record Type: Journal Article
• Authors: Wentzel, Andreas; Hilt, Oliver; Würfl, Joachim; Heinrich, Wolfgang
• Is Part Of: International journal of microwave and wireless technologies. Volume 12:Issue 10(2020)
• Page Start: 945
• Page End: 953
• Publication Date: 2020-12-23
• Subjects: Buck converter, -- DC/DC converter, -- GaN, -- power amplifiers, -- envelope tracking; Wireless communication systems -- Periodicals; Microwave circuits -- Periodicals; Radio frequency -- Periodicals; 621.381305
• DOI: 10.1017/S1759078720000380
• Languages: English
• ISSNs: 1759-0787

Abstract

Abstract: The paper presents a highly efficient GaN-based synchronous buck converter suitable for switching in the lower GHz range. The module includes a very compact 2-stage GaN half-bridge converter MMIC (monolithic microwave integrated circuit) for low parasitic inductances between switches and drivers and a hybrid output network with core-less inductors to avoid ferrite losses. At 1 GHz switching frequency the buck converter achieves with pulse-width modulated (PWM) input signals power loop conversion efficiencies up to 78% for 40 V operation and output voltages up to 33 V. For 100 MHz the power loop efficiencies peak at 87.5% for 14.5 W conversion to 25 V. By changing the output network to a 2 nd order low-pass with 700 MHz cut-off frequency the module has been characterized for the use as a supply modulator in very broadband envelope tracking systems with modulation bandwidths of up to 500 MHz. For 1 GHz switching frequency the power-added efficiency peaks at 74% for a 90% duty-cycle PWM input signal. The novelty of this work is that for the first time a buck converter design proves highest flexibility supporting different applications from very compact DC converters to microwave power amplifier efficiency enhancement techniques as well as efficient high frequency switching up to 1 GHz.