A high-efficiency, high-frequency boost converter using enhancement mode GaN DHFETs on silicon

• Published in: 2010 IEEE Energy Conversion Congress and Exposition pp. 3296 - 3302
• Main Authors: Everts, Jordi, Das, Jo, Van den Keybus, Jeroen, Genoe, Jan, Germain, Marianne, Driesen, Johan
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.09.2010
• Subjects: boost converter; Converters; Current measurement; DH-HEMTs; enhancement mode (E-mode); Gallium nitride; GaN DHFET; high efficiency; Inductors; Logic gates; very high frequency; Voltage measurement; wide bandgap
• ISBN: 1424452864; 9781424452866
• ISSN: 2329-3721
• DOI: 10.1109/ECCE.2010.5618323

A boost converter was constructed using a high voltage enhancement mode (E-mode) AlGaN/GaN/AlGaN DHFET transistor grown on Si<;111>. The very low dynamic onresistance (R dyn ≈ 0.23 Ω) and very low gate-charges (e.g. Q gate ~15 nC at Vos = 200 V) result in minor transistor losses. Together with a proper design of the passive components and the use of SiC diodes, very high overall efficiencies are reached. Measurements show high conversion efficiencies of 96.1% (P out = 106 W, 76 to 142 V at 512.5 kHz) and 93.9% (P out = 97.5 W, 78 to 142 V at 845.2 kHz). These are, to our knowledge, the highest efficiencies reported for an enhancement mode GaN DHFET on Si in this frequency range. The transistor switching losses are concentrated in the turn-on interval, and dominate at high frequencies. This is due to a limited positive gate-voltage swing, as the gate-source diode restricts the positive drive voltage.