Selecting GaN transistors for avionics power
German aerospace company AES Aircraft Elektro/Elektronik System has launched its first avionics power supplies using 650V gallium nitride GaN FET transistors.
The company’s latest Switch Mode Power Supplies are currently used by large CS-25 aircraft manufacturers such as the Airbus A318-A321, A330, A340, A380 and Boeing B767, B787 VIP aircraft and use Transphorm’s GaN FETs to increase overall system efficiency by more than 10 percent over silicon-based designs.
The two GaN based avionics Switch Mode Power Supplies are the PS250X 500 W system and the PS6120 1200 W system. Both products support a 96-130 VAC/360 Hz – 800 Hz input voltage with a 28 VDC continuous power output at 15 amps for the 500 W system and 42 amps for the 1200 W system.
AES certified the PS250X and PS6120 as DO-160 compliant, meeting the more than 25-point stringent Standard of the Radio Technical Commission for Aeronautics (RTCA). This Standard assesses system impact and performance under various external and internal conditions on aircraft, ranging from pressure and temperature to voltage spikes and RF emissions.
The flagship 1.4 kg 500 W PS250X is the industry’s first passively cooled power supply at 420 W and deploys Transphorm’s GaN in a single-phase CCM boost power factor correction (PFC) topology. It offers more than 92 percent overall system efficiency at full load, with a 0.98 power factor and 200 mVpp nominal at 115 VAC/400 Hz input at full load.
The 4.0kg 1200 W PS6120 deploys Transphorm’s GaN in a fan-cooled, three-phase CCM boost PFC topology. It offers more than 91.5 percent overall system efficiency at full load, and has the same power factor and nominal ripple voltage at 115 VAC/400 Hz input at full load as the PS250X.
“The aviation industry is working toward reducing climate impact through any means possible,” said Dr Andreas Hammer, Head of Competence Center Power at AES.
Next: Selecting GaN FETs
“Considering, we sought out Transphorm’s GaN to replace previously used Silicon MOSFETs so that we could provide a more efficient, lighter weight power supply,” he said. “These supplies have the potential to make a notable impact when considering each aircraft deploys several such PSUs. After only a year of redesign, we were able to offer our customers a better power solution, while also raising the performance bar within our own industry.”
AES reviewed GaN power switch converters from several semiconductor manufacturers. The company ultimately selected Transphorm’s 650 V devices due primarily to its ease of drivability and designability—specifically because Transphorm’s GaN FETs do not require custom drivers. As a result, system design is simplified while engineers can drive the switches using technology they are already familiar with (i.e. drivers and packages). Other factors affecting AES’ selection included Transphorm’s proven reliability—which is underscored by its power supply platform earning both a JEDEC qualification and AEC-Q101 qualification at 175°C.
“Transphorm designed its GaN devices to enable designers, not challenge them,” said Philip Zuk, VP of Worldwide Technical Marketing and NA Sales, Transphorm., “Our two-switch normally-off GaN devices come in standard packages and require minimal supporting circuitry to drive them, which reduces the overall system size, increases reliability, and simplifies design. It’s crucial to us that our customers can come to market quickly with a product they have confidence in. We’re honored to be AES’ GaN supplier of record and are proud that they appreciate the work we’ve done to bring the benefits of GaN technology to the masses.”