A 10-MHz GaNFET-Based-Isolated High Step-Down DC–DC Converter: Design and Magnetics Investigation

Abstract

This paper presents design of an isolated high-step-down DC-DC converter based on a class-DE power stage, operating at a 10 MHz switching frequency using enhancement mode Gallium Nitride (GaN) transistors. The converter operating principles are discussed, and the power stage design rated for 20 W is presented for a stepdown from 200-300 V to 0-28 V. Commercially available magnetic materials were explored and the highfrequency (HF) resonant inductor and transformer designs using a low-loss Fair-Rite type 67 material are presented. Finite element simulations have been performed to estimate the parameters of magnetics at 10 MHz. Experimental results are presented at 12 W, 254 V to 22 V and 5 W, 254 V to 14 V on a laboratory prototype operating at 10 MHz. At 20 W the experimental prototype achieved an efficiency of 85.2%.

A Family of DC–DC Converters With High Step-Down Voltage Capability Based on the Valley-Fill Switched Capacitor Principle

“…Substituting the equations presented in Tables I and II in (11) and having the boundary operational conditions defined by (10), the total losses of the converter I-HSD-2 can be estimated for the entire range of D a and D b . The loss behavior, based on the trajectory of the duty cycles D a and D b , is shown in Fig.…”

“…There are two main categories of step-down converters in the literature: isolated and non-isolated converters. On one hand, isolated converters [10] are able to achieve a high stepdown conversion ratio with minimal number of components in the power stage although the magnetic design of the isolated transformers is the main challenge in these circuits [11]. Transformerless converters, on the other hand, do not introduce the magnetic design challenges but suffer from a higher number of power semiconductors in the power stage.…”

Comprehensive and Simplified Numerical Design Procedure for Class-E Switching Circuits

“…H IGH frequency amplifiers have been used in a wide range of applications, such as wireless power transfer (WPT) systems [1]- [5], resonant power converters [6]- [13], and induction heating [14], [15]. It is effective to increase the switching frequency for the size reduction of the magnetic components.…”

“…It is effective to increase the switching frequency for the size reduction of the magnetic components. With the development of the nextgeneration wide-bandgap semiconductors such as Gallium Nitride (GaN), it becomes possible to push the switching frequency up to the ISM-frequency band, such as 6.78 MHz and 13.56 MHz [1]- [4], [12], [13].…”

“…For reducing the switching loss, the soft-switching technique is mandatory. The class-E switching circuit families, such as class-E [1], [3]- [5], [7]- [10], [14], [16]- [28], class-DE [13], [29], and class-EF [1], [30] ampifiers, have gained researcher's interest in recent years. This is because they can achieve the class-E zero-voltage switching (ZVS) and zero-derivative switching (ZDS) conditions, which reduces the switching loss significantly.…”