Enphase Energy, Inc., a global energy technology company, and Infineon Technologies AG today announced that Enphase will deploy the world’s first 900 V gallium nitride (GaN) monolithic bidirectional switch (BDS) devices, designed to operate in Enphase solid-state transformer power modules. The devices extend GaN technology to 900 V while retaining the high-frequency switching capabilities that enable compact, efficient power conversion.

Enphase has pioneered the system-level development and demonstration, building on more than 10 years of in-house research into GaN power conversion, with device technology and engineering expertise from Infineon. Enphase is among the first to bring 650 V GaN BDS devices into volume production power electronics, and GaN HEMT technology is already operating in Enphase IQ9™ Microinverters deployed in the field. Extending that work with Infineon beyond 650 V, using Infineon's CoolGaN™ bidirectional switch portfolio, opens the door further to medium-voltage systems.

The 900 V GaN devices allow Enphase to continue using components rated below 1 kV, expanding the design options towards high-performance power conversion typically governed by silicon carbide (SiC). This supports a single-stage architecture with high-frequency switching, low electromagnetic interference (EMI), and fewer points of failure. Switching at such high frequency shrinks the transformers and other magnetics needed in the power stage, cutting size, weight, and cost.

Higher-voltage switches within that low-voltage envelope change the economics of power conversion. In a solid-state transformer, a medium-voltage input can be handled by fewer inverters connected in series while retaining the low switching losses and intrinsic bidirectionality of GaN BDS. Fewer building blocks means lower system-level losses at the same input current, fewer components in the power path, and a lower total switch count. On the DC side, higher-voltage unidirectional switch (UDS) devices allow power to be generated at a unipolar 800 volts rather than split +/-400 V buses, and support future 1,500 VDC bus architectures through split +/-750 V generation with fewer switches and lower bridge losses.

The technology is particularly relevant to the Enphase IQ® Solid-State Transformer (IQ SST), the company's solid-state transformer platform for AI data centers, where power density, efficiency, and uptime drive the economics of every megawatt deployed. The same devices are expected to benefit commercial solar inverters by enabling three-phase, line-to-line designs for 480 V applications in the United States and 400 V applications elsewhere, again with fewer switches, lower losses, and lower cost

"Enphase asks more of our technology than almost anyone, and medium-voltage solid-state transformers are exactly where high-voltage GaN proves its value," said Johannes Schoiswohl, senior vice president and head of GaN Systems Business Line at Infineon. "Moving past 650 V lets system designers strip cost and loss out of the architecture rather than optimizing around it."

"GaN is not new to us. It has been running in Enphase IQ9 Microinverters in the field, and that field data is why we trust it in a megawatt-class system," said Hans van Antwerpen, senior vice president and chief technology officer at Enphase Energy. "Moving to 900 V gives us more voltage headroom without giving up high-frequency switching, and it allows us to stay with components rated below 1 kV while reducing the number of converters in the system. Fewer parts in the power path means higher efficiency and fewer things that can fail."