IN Brief:
- Infineon and Enphase have announced 900 V monolithic GaN bidirectional switches for solid-state transformer modules.
- Testing has been completed and devices are being integrated into Enphase IQ SST development builds.
- Production qualification is expected next; no commercial deployment date has been confirmed.
Infineon Technologies and Enphase Energy have announced 900 V gallium nitride monolithic bidirectional switches for solid-state transformer modules intended for artificial intelligence data centres. The companies said on 26 October 2026 that the CoolGaN devices have been successfully tested and are being integrated into development builds of Enphase’s IQ Solid-State Transformer platform. Production qualification is expected to follow, but neither company has specified a date or confirmed commercial deployment. The development concerns higher-voltage power conversion components under evaluation, not the commissioning of a new data centre electrical system.
Infineon describes the devices as the first 900 V GaN monolithic bidirectional switches, extending its existing collaboration with Enphase on 650 V devices. GaN is a semiconductor material used in power electronics where fast switching can make conversion equipment more compact. The new rating increases the voltage a device is designed to block while retaining high-frequency operating characteristics. This may allow system designers to use fewer conversion stages or series-connected building blocks in some architectures. Those system-level benefits depend on the eventual circuit design, its thermal management and the performance established during qualification.
Bidirectional switching is an important part of the proposed power conversion architecture. Infineon says its monolithic bidirectional devices integrate voltage blocking and current conduction in both directions within one component. This can simplify arrangements that otherwise require additional semiconductors to control power flow or withstand voltage of opposite polarity. In a solid-state transformer, those characteristics are relevant where power conversion stages need to manage energy flow between different voltage levels. They do not imply that every transformer using the device will automatically be bidirectional at the full system level.
A conventional transformer changes alternating-current voltage through magnetic induction and operates at the network frequency. A solid-state transformer combines power electronic conversion with high-frequency magnetic components to perform voltage adaptation and potentially support more active control of power flows. High-frequency operation can allow certain magnetic components to be smaller for a given power-processing requirement. It also creates engineering demands in switching loss, electromagnetic compatibility, cooling, insulation and protection. The claimed advantages of the 900 V switches therefore have to be assessed within the complete electrical design rather than from the semiconductor voltage rating alone.
Enphase says the 900 V components will contribute to a more compact power architecture for its IQ SST system, which is being developed for megawatt-class AI computing installations. High-density computing loads place pressure on the space, efficiency and reliability of electrical distribution equipment. Reducing the number of power conversion stages could cut the number of devices and electrical connections in the power path. However, the partners have not released measured full-system efficiency figures, comparative failure-rate results or the qualified power rating of a finished installation using these new devices.
Enphase’s technical explanation also sets out how higher-voltage components could serve future direct-current distribution systems. It describes the industry shift towards an 800 VDC bus and possible 1,500 VDC architectures. The company’s release distinguishes its new bidirectional devices from higher-voltage unidirectional switches used for particular DC generation stages. Accordingly, the 900 V rating should not be interpreted as a claim that a single 900 V device can by itself switch a complete 1,500 V DC network. Converter topology, the number of series stages and insulation arrangements remain essential to the voltage an assembled system can handle.
The partnership draws on previous Enphase experience with gallium nitride in solar microinverters. The company says GaN technology is already deployed in its IQ9 Microinverter products, and that it worked with Infineon on 650 V bidirectional switches. That operating history is relevant to the organisations’ confidence in the material, but the 900 V devices constitute a further product development requiring their own qualification. Field experience from one power electronics application is not a substitute for proving reliability under the electrical and thermal conditions of an AI data centre transformer.
Both companies also identify possible applications outside computing infrastructure. Higher-voltage GaN switches may support commercial solar inverters using three-phase designs at 480 V in the United States and 400 V in other markets. The proposed benefit is simpler power stages with lower losses and fewer components. These are anticipated applications rather than announced supply contracts or installations. The companies have not disclosed component prices, manufacturing volumes, customer delivery commitments or a commercial production schedule for the 900 V devices.
For electrical designers, the technical challenge is to translate high-frequency switching into a robust conversion system with suitable fault response, electromagnetic compatibility and maintainable operation. Increasing power density can change thermal concentration, while removing conversion stages may also alter protection and redundancy choices. Bidirectional devices add configuration possibilities but the required control and system architecture must still be engineered. The companies have not published independently verified operating data establishing energy, space or lifecycle cost savings for a completed installation using the new switches.
The immediate milestone is the successful testing of the CoolGaN 900 V monolithic bidirectional switches and their integration into IQ SST development builds. Production qualification is the next identified step, with no public timetable established. If the devices meet Enphase’s system requirements, they could broaden the options for compact medium-voltage conversion and emerging high-voltage DC distribution in AI infrastructure. Until qualification and commercial commissioning occur, the technology should be described as an active semiconductor and power-system development, not as an already deployed 900 V GaN transformer product.
