News: Microelectronics
29 June 2026
Infineon introduces first 24kW SiC-based battery backup unit reference design for high-voltage DC bus architectures in AI data centers
Infineon Technologies AG of Munich, Germany has introduced a 24kW battery backup unit (BBU) DC–DC reference design for high-voltage (HV) DC bus architectures in artificial intelligence (AI) data centers. The design is said to be the first of its kind to operate directly from a battery stack to an 800V DC bus, using 650V and 1200V silicon carbide (SiC) technology. It achieves a power density of 450W/in3 and efficiency exceeding 99% within the same physical form factor as existing low-voltage (LV) BBU implementations, addressing a key infrastructure bottleneck as data centers transition to higher-voltage DC distribution.
“Powering AI at scale demands a systemic approach that optimizes every stage of the power delivery chain, from grid connection to the processor core,” says Magdalene Boebel, senior VP & business line head Power System ICs at Infineon. “Our 24kW high-voltage BBU reference design, operating directly on an 800V DC bus, sets a new benchmark in power density and efficiency, giving data-center architects a fully integrated solution to meet the most demanding AI infrastructure requirements.”
The reference design is based on a multi-level, multi-phase non-isolated architecture combining stacked, interleaved and coupled boost and buck stages. This approach reduces magnetic component volume directly, without relying on flying capacitors. A shared switching-leg topology establishes a common current path between the charge and discharge stages, enabling zero-voltage switching (ZVS) across the operating range. The outcome is reduced current ripple, fully integrated magnetics, and fast transient response, which are characteristics increasingly critical as AI server power draw becomes more dynamic and less predictable.
Picture: Infineon’s new 24kW battery backup unit DC–DC reference design for high-voltage DC bus architectures in AI data centers.
The compact module measures 112mm x 88mm x 118mm and integrates a 24kW main power stage with a 2.4kW auxiliary supply. Charger and discharger blocks share the EMI filter, capacitors and protection MOSFETs, reducing total component count. Best-in-class SiC junction gate field-effect transistors (JFETs) provide ORing and hot-swap capability. A planar transformer combined with CoolSET implements the auxiliary SMPS in a compact, cost-efficient footprint.
The DC–DC conversion stage is built around the CoolSiC MOSFET IMT65R033M2H, a 650V device qualified for bidirectional buck-boost DC–DC operation in HV BBU applications. Its low conduction and switching losses support stage efficiencies of higher than 99%, reducing thermal load at rack level. During grid disturbances, generator switchovers or outages, the device transfers energy rapidly between the HV DC bus and the battery with minimal losses, extending hold-up time reliably. A 650V breakdown rating, robust body diode, 175°C junction temperature rating, and .XT packaging technology provide resilience under voltage spikes, high dv/dt transients, and continuous thermal cycling. Consistent Vgs(th) characteristics across devices simplify multi-phase design and support redundant rack configurations. This architecture is documented in Infineon's REF_12KW_HFHD_PSU reference design, which demonstrates the IMT65R033M2H in high-power DC–DC stages for rack-level HV BBU applications.
The complete bill of materials comprises the following Infineon components: CoolSiC MOSFET 650V Generation 2 including the IMT65R033M2H, EiceDRIVER gate drivers, TLE497x current sensors, PSOC Performance line MCU, CoolSET IC for the auxiliary SMPS, and a 1.7kV SiC MOSFET.
Further design characteristics include reduced common-mode noise with negligible AC components, and fully integrated magnetics. Three power cards provide mechanical connections for the DC positive, DC negative and midpoint rails while simultaneously serving as structural elements of the assembly, contributing to the solution’s overall compactness.
The transition to higher-voltage DC bus architectures in data centers is driven by efficiency and distribution loss advantages at rack and facility scale. BBUs are a key component of this infrastructure shift, maintaining continuous power delivery to AI servers during grid events. The 24kW HV BBU reference design demonstrates how SiC-based DC–DC conversion can meet the density, efficiency and reliability requirements of this transition. Infineon’s portfolio spanning silicon (Si), SiC and gallium nitride (GaN) covers the full power delivery chain from grid to processor core.
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