Enphase and Infineon Push GaN to 900 V for AI Data Center Solid-State Transformers

Overview

Enphase Energy and Infineon Technologies announced on Oct. 26, 2026, what the companies describe as the world’s first 900 V gallium nitride (GaN) monolithic bidirectional switch (BDS) devices. Enphase will deploy the devices, which are designed to operate in Enphase solid-state transformer power modules. The 900 V rating extends GaN technology while retaining the high-frequency switching capabilities that enable compact, efficient power conversion.

The announcement links a device-level milestone to a system-level platform: Enphase’s IQ Solid-State Transformer (IQ SST), aimed at AI data centers. Enphase says it has 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 already operates in Enphase IQ9 Microinverters deployed in the field. Enphase describes itself as the world’s leading supplier of microinverter-based solar and battery systems, with approximately 89.4 million microinverters shipped and approximately 5.3 million Enphase-based systems deployed in more than 165 countries.

Technical Details: 900 V BDS and Single-Stage Architecture

The 900 V GaN devices allow Enphase to continue using components rated below 1 kV, expanding design options toward high-performance power conversion typically governed by silicon carbide (SiC). According to the companies, 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.

In a solid-state transformer, higher-voltage switches within that low-voltage envelope change the economics of power conversion. 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. They also support future 1,500 VDC bus architectures through split +/-750 V generation with fewer switches and lower bridge losses.

Qualification and Deployment Path

The 900 V GaN BDS devices have been successfully tested and are now being integrated into IQ SST development builds, with production qualification expected to follow. The move beyond 650 V, using Infineon’s CoolGaN bidirectional switch portfolio, opens the door further to medium-voltage systems. Enphase’s prior 650 V volume production and IQ9 field deployment provide the company with a bridge from proven lower-voltage GaN to higher-voltage system designs.

Market Context: GaN Versus Silicon Carbide

High-performance power conversion at higher voltages has been strongly associated with SiC. The 900 V GaN BDS does not simply replace SiC; it broadens the design space below 1 kV. By staying within that envelope, Enphase can use GaN’s high-frequency switching and intrinsic bidirectionality while avoiding a move to a higher-voltage device class. The article frames the shift as changing the economics of power conversion: fewer parts in the power path, lower system-level losses, and a lower total switch count rather than optimizing around a more complex architecture.

Implications for AI Data Centers

The technology is particularly relevant to IQ SST, Enphase’s solid-state transformer platform for AI data centers, where power density, efficiency, and uptime drive the economics of every megawatt deployed. A medium-voltage input handled by fewer series-connected inverters can reduce system-level losses and component count. On the DC side, unipolar 800 V generation and future 1,500 VDC architectures supported through split +/-750 V generation point to higher-voltage, more efficient power distribution for next-generation AI data centers.

Commercial Solar and Broader Power Conversion

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. That suggests the 900 V platform is not limited to data-center SSTs; it can also cascade into Enphase’s core commercial solar business.

Industry Impact and Future Outlook

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

The announcement signals a push toward medium-voltage solid-state transformers and higher-voltage DC buses, with 900 V GaN BDS devices positioned between established 650 V GaN and higher-voltage SiC. If production qualification and integration proceed as expected, the devices could influence AI data center power delivery, commercial solar inverters, and other high-performance conversion applications. The companies’ forward-looking statements nonetheless frame these benefits as expected capabilities subject to qualification and deployment.