Efficiency optimization of totem pole PFC with Gallium Nitride semiconductors

99% Efficiency True-Bridgeless Totem-Pole PFC Based on GaN HEMTs

Liang Zhou, member IEEE and YiFeng Wu, member IEEE Transphorm, Inc. 75 Castilian Dr., Goleta, CA, 93117 USA [email protected] Abstract: This paper presents a true bridgeless totem-pole Power-Factor-Correction (PFC) circuit using GaN HEMT. Enabled by a diode-free GaN power HEMT bridge with low reverse-recovery charge, very-high-efficiency single-phase AC-DC conversion is realized using a t...

Gallium Nitride Photoconductive Detectors

Since 1994, the Applied Physics Laboratory has been collaborating with NASA Goddard Space Flight Center to develop photodetectors based on gallium nitride and aluminum gallium nitride material produced in the Milton S. Eisenhower Research and Technology Development Center. This article describes the results of our collaboration and highlights the development of gallium nitride photodetectors wi...

Ultralow wear of gallium nitride

Development of Gallium Nitride Substrates

Prominent progress has been made in nitride semiconductor since high bright blue LED has developed in 1993. It has also expanded to an industry after applied to white LED. These LEDs are produced by the epitaxial growth of nitride semiconductor layers on sapphire (a Al2O3) substrate. On the other hand, recording density in optical disks has increased from CD in 1980s to DVD in latter 1990s. Las...

Carrier Localization in Gallium Nitride

In wide bandgap GaN a large number of interesting and important scientific questions remain to be answered. For example, the large free electron concentration reaching 1019 to 1020 cm-3 in nominally undoped material are ascribed to intrinsic defects because no chemical impurity has been found at such high concentrations. According to theoretical models a nitrogen vacancy acts as a donor but its...