Why 48 V still matters in AI/ data-center systems
Introduction
As the power demands of AI and cloud computing accelerate, data-center design is evolving faster than ever. New high voltage direct current (HVDC) architectures like ±400 V DC and 800 V DC promise higher power density, lower transmission losses, and reduced power system complexity. Yet despite these rapid changes, one voltage remains at the heart of modern data center compute platforms: 48 V DC.
With these new HVDC architectures emerging, 48 V may appear mature or even transitional - a legacy from telecom systems or earlier server generations. But the reality is more complex, especially within the rack. For today’s AI-driven infrastructure, 48 V remains a critical enabler of scalable, efficient power delivery from rack to processor, and will continue to provide distinct benefits as system architectures evolve.
A proven balance between safety and efficiency
The enduring strength of 48 V lies in its sweet spot between power density and safety. At this voltage, distribution currents are significantly lower than in traditional 12 V systems, reducing copper losses and cable sizes. Yet 48 V still remains within the Safety Extra-Low Voltage (SELV) range, simplifying insulation, protection, and system certification. It also offers the commercial benefits of a well-established, long-standing ecosystem.
In practice, most 48 V systems operate closer to 50 V or 54 V DC to compensate for voltage drops and optimize converter efficiency – but the principle remains the same: high efficiency without high-voltage complexity. 48/54 V power shelves, busbars, and rack distribution networks can be implemented with mature technology, proven reliability, and globally available components.
Essential in both legacy and next-generation architectures
While hyperscalers are exploring ±400 V DC and 800 V DC distribution for the next wave of AI power racks, it’s important to remember that those numbers represent the maximum voltage of the system, and don’t tell the entire story. In fact, HVDC systems will typically terminate at 48 V (or 54 V) conversion stages within the rack or power shelf.
This intermediate bus remains the link between high-voltage distribution and low-voltage point-of-load (PoL) regulation, supplying hundreds of amps to processors, GPUs, and accelerators.
Even as overall data center voltages increase, 48 V continues to bridge system-level efficiency and board-level precision. In many platforms, 48 V feeds further intermediate buses at 12 V or 6 V, before final sub-1 V regulation at the chip through either lateral or vertical power delivery solutions. This tiered approach allows designers to balance efficiency, transient performance, and layout flexibility across densely packed boards.
Ready for the next decade of compute
Far from being replaced, 48 V continues to be a key piece of the puzzle for even the most ambitious and forward-thinking data centers.
It is the unifying layer between evolving HVDC distribution and advanced board-level regulation - a stable, flexible standard that allows system designers to innovate without constant redesign of the power backbone.
As AI workloads grow from kilowatts to tens or even hundreds of kilowatts per rack, 48 V (and its practical 50 V or 54 V implementations) continue to provide the efficiency, scalability, and safety the industry depends on.
At Flex Power Modules, we believe powering intelligence starts with intelligent power architecture, and 48 V remains one of the smartest choices you can make.