Enphase and Infineon Put 900V GaN Switches Into AI Data Center Transformers

Enphase Energy and Infineon Technologies have deployed 900-volt gallium nitride (GaN) monolithic bidirectional switch (BDS) devices inside Enphase's solid-state transformer power modules — a combination the partners call a world first for the voltage class.

The switches are built for Enphase's IQ Solid-State Transformer (IQ SST), a product line aimed at AI data centers, where medium-voltage power conversion is becoming a procurement bottleneck. The devices have passed testing and now enter IQ SST development builds, with production qualification expected to follow.

What changes at 900V?

The BDS devices let Enphase keep working with components rated below 1kV while still pushing into high-performance power conversion, a domain usually served by silicon carbide (SiC). Within an SST, Enphase says, the switches cut switching losses and reduce the component count in the power path.

On the DC side, higher-voltage unidirectional switch (UDS) devices enable unipolar 800V power generation instead of split +/-400V buses. They also support future 1,500VDC bus architectures through split +/-750V generation, using fewer switches and lower bridge losses.

"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 the GaN Systems Business Line at Infineon. "Moving past 650V lets system designers strip cost and loss out of the architecture rather than optimizing around it."

Why Enphase trusts the chemistry

Enphase is not betting on unproven silicon. GaN transistors already run in the company's IQ9 Microinverters in the field, and that installed base informed the decision to scale the technology to megawatt-class systems.

"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.

Van Antwerpen framed the 900V move as a trade that gives away nothing. "Moving to 900V gives us more voltage headroom without giving up high-frequency switching, and it allows us to stay with components rated below 1kV while reducing the number of converters in the system. Fewer parts in the power path means higher efficiency and fewer things that can fail."

How hot is the SST market?

Solid-state transformers are moving from pilot projects to signed contracts across the data center sector. Vantage this month agreed a deal with SST manufacturer Heron Power to secure more than 1GW of Heron's transformers for deployment across Vantage's hyperscale data center portfolio. Heron also counts Crusoe among its partners.

Infineon is hedging across materials. Last month the German semiconductor firm signed a deal with Eaton to supply SiC power devices for Eaton's medium-voltage SST platform — a parallel track to the GaN work with Enphase.

Status and next steps

The 900V GaN BDS devices have completed successful testing. Integration into IQ SST development builds is underway, and production qualification is the next gate before volume deployment.

For AI data center operators, the significance is straightforward: higher-voltage GaN switching could lower component counts, cut losses and shorten the qualification path for medium-voltage power delivery.