Infineon has introduced a 24 kW battery backup unit (BBU) DC-DC reference design intended for high-voltage DC bus architectures in AI data centers. The design targets an 800 V DC bus and operates directly from a battery stack using 650 V and 1200 V silicon carbide (SiC) devices. Infineon lists 450 W/in³ power density and efficiency exceeding 99 percent, while keeping the same physical form factor as current low-voltage BBU implementations.
Moving rack power distribution to higher-voltage DC can reduce current for a given power level, which eases conductor losses and distribution hardware constraints. But it also forces a rethink of BBU conversion stages, protection, and hot-swap behavior at higher bus voltages, especially as AI racks push higher, faster-changing loads.
Infineon’s reference design uses a multi-level, multiphase non-isolated architecture that combines stacked, interleaved, and coupled boost and buck stages. Infineon says the approach reduces magnetic component volume without using flying capacitors. The charger and discharger share a switching-leg topology to establish a common current path between charge and discharge stages, enabling zero-voltage switching (ZVS) across the operating range. Infineon also calls out reduced current ripple, integrated magnetics, and fast transient response as design outcomes.
The module measures 112 x 88 x 118 mm and integrates a 24 kW main power stage plus a 2.4 kW auxiliary supply. Infineon says the charger and discharger blocks share the EMI filter, capacitors, and protection MOSFETs to reduce total component count. The auxiliary SMPS uses a planar transformer combined with CoolSET.
The DC-DC conversion stage is built around the CoolSiC MOSFET IMT65R033M2H, a 650 V device that Infineon positions for bidirectional buck-boost DC-DC operation in high-voltage BBU applications. Infineon attributes stage efficiencies above 99 percent to low conduction and switching losses and says that helps reduce thermal load at the rack level. Infineon lists a 175 °C junction temperature rating, a robust body diode, a 650 V breakdown rating, and .XT packaging technology for resilience under voltage spikes, high dv/dt transients, and thermal cycling.
“Powering AI at scale demands a systemic approach that optimizes every stage of the power delivery chain, from grid connection to the processor core,” said Magdalene Boebel, Senior Vice President and Business Line Head Power System ICs at Infineon.
Availability details and technical documentation for Infineon’s BBU solutions for AI data centers are posted at infineon.com/bbu-ai.
Source: Infineon
