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 2nd 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.

中文翻译：

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基于 GaN 的高效 GHz 开关同步降压转换器模块

本文提出了一种高效的基于 GaN 的同步降压转换器，适用于在较低 GHz 范围内进行开关。该模块包括一个非常紧凑的 2 级 GaN 半桥转换器 MMIC（单片微波集成电路），用于在开关和驱动器之间实现低寄生电感，以及一个带有无芯电感器的混合输出网络，以避免铁氧体损耗。在 1 GHz 开关频率下，降压转换器通过脉宽调制 (PWM) 输入信号实现高达 78% 的 40 V 操作和高达 33 V 输出电压的功率环路转换效率。对于 100 MHz，功率环路效率峰值为 87.5%将 14.5 W 转换为 25 V。通过将输出网络更改为 2nd该模块具有 700 MHz 截止频率的阶低通特性，可用作调制带宽高达 500 MHz 的超宽带包络跟踪系统中的电源调制器。对于 1 GHz 开关频率，90% 占空比 PWM 输入信号的功率附加效率峰值为 74%。这项工作的新颖之处在于，降压转换器设计首次证明了最高的灵活性，支持从非常紧凑的直流转换器到微波功率放大器效率增强技术以及高达 1 GHz 的高效高频开关等不同应用。