Considerations of Physical Design and Implementation for 5 MHz-100 W LLC Resonant DC-DC Converters

Akinori Hariya,Ken Matsuura,Yoichi Ishizuka,Hiroshige Yanagi,Satoshi Tomioka,Tamotsu Ninomiya

doi:10.1155/2016/4027406

Abstract

Recently, high power-density, high power-efficiency, and wide regulation range isolated DC-DC converters have been required. This paper presents considerations of physical design and implementation for wide regulation range MHz-level LLC resonant DC-DC converters. The circuit parameters are designed with 3–5 MHz-level switching frequency. Also, the physical parameters and the size of the planar transformer are optimized by using derived equations and finite element method (FEM) with Maxwell 3D. Some experiments are done with prototype LLC resonant DC-DC converter using gallium nitride high electron mobility transistors (GaN-HEMTs); the input voltage is 42–53 V, the reference output voltage is 12 V, the load current is 8 A, the maximum switching frequency is about 5 MHz, the total volume of the circuit is 4.1 cm3, and the power density of the prototype converter is 24.4 W/cc.

Highlights

High power-density and high power-efficiency isolated DC-DC converters have been required in information and communication technology (ICT) facilities
The regulated MHz-level operated isolated DC-DC converters have been studied with wide input voltage: 60–120 V input voltage, 20 V output voltage, 2.6 MHz switching frequency, and 50 W output power, series resonant DC-DC converter [8]; 36–72 V input voltage, 12 V output voltage, 5 MHz switching frequency, and 30 W output power, flyback DC-DC converter [9]; 110–250 V input voltage, 15 V output voltage, 2 MHz switching frequency, and 45 W output power, quasi-square-wave zero-voltage switching three-level half-bridge DC-DC converter [10]; 60–120 V input voltage, 15 V output voltage, 3–4.5 MHz switching frequency, and 40 W output power, zero-voltage switching (ZVS) half-bridge DC-DC converter [11]
The prototype LLC resonant DC-DC converter using GaN-HEMTs is tested with open loop

Summary

Introduction

High power-density and high power-efficiency isolated DC-DC converters have been required in information and communication technology (ICT) facilities. The regulated MHz-level operated isolated DC-DC converters have been studied with wide input voltage: 60–120 V input voltage, 20 V output voltage, 2.6 MHz switching frequency, and 50 W output power, series resonant DC-DC converter [8]; 36–72 V input voltage, 12 V output voltage, 5 MHz switching frequency, and 30 W output power, flyback DC-DC converter [9]; 110–250 V input voltage, 15 V output voltage, 2 MHz switching frequency, and 45 W output power, quasi-square-wave zero-voltage switching three-level half-bridge DC-DC converter [10]; 60–120 V input voltage, 15 V output voltage, 3–4.5 MHz switching frequency, and 40 W output power, zero-voltage switching (ZVS) half-bridge DC-DC converter [11] These isolated DC-DC converters achieve high power efficiency.

The Consideration of Circuit Parameter Design

The Physical Design Considerations of Planar Transformer

Experimental Results

Conclusions