Five-Megahertz PWM-Controlled Current-Mode Resonant DC–DC Step-Down Converter Using GaN-HEMTs

Abstract

High power efficiency and high power density are required in regulated isolated DC-DC converters. In this paper, a novel pulse width modulation (PWM) control method which is suitable for the isolated current-mode resonant DC-DC converter operated at MHz level switching frequency is proposed. The output voltage with the proposed method can be regulated with no additional components at fixed switching frequency. In addition, zero voltage switching (ZVS) of primaryside switches at turn-on can be maintained. The principle of the proposed method and the method of ZVS operation in the proposed method are explained. Some experiments have been performed with a 5MHz isolated step-down DC-DC converter using Gallium Nitride High Electron Mobility Transistors (GaN-HEMTs); the output voltage is 12V and the total volume of the circuit is 16.14cm 3 . With the proposed PWM control method, input voltage range is 42-45.5V, and maximum load current range is 10A at V i = 45.5V. The ZVS of the primary-side switches at turn-on is confirmed in all experimental regions, and the maximum power efficiency is 89.2%.

Parseval’s Theorem Used for the Inductor Analysis in High-Frequency Boost Converters

“…Traditional analysis of power converters requires design tools intended to deal with operation frequencies around hundreds of kilohertz [1]. However, outstanding advances in Gallium Nitride -High Electron Mobility Transistors (GaN-HEMTs) enlarge the operation condition of power converters to the range of megahertz [2] [3]. Indeed, this extended bandwidth requires innovative design methodologies to achieve a trade-off between high-frequency and high-power conditions [4].…”