Finding the ideal power architecture for AI data centers
Optimizing power electronics
With the rise of AI, machine learning, and more intensive cloud computing, modern data centers are tackling unprecedented levels of energy demand. These power-hungry applications place immense pressure on CPUs and GPUs, requiring innovative solutions to balance performance with energy efficiency. In this blog, we explore strategies for optimizing power distribution in data centers, highlighting intermediate bus converters (IBCs) as a critical component for handling increasing power loads while maintaining system efficiency.
The growing energy challenge
Emerging technologies like AI and cryptocurrency mining are accelerating data center energy consumption. According to the International Energy Agency (IEA), global data center electricity use in 2022 reached 460 terawatt-hours (TWh) and could more than double by 2026. To put this into perspective, these energy demands rival the total electricity consumption of Japan. This rapid growth highlights the urgent need for efficient power delivery networks (PDNs). By optimizing power architectures, data centers can achieve environmental sustainability and reduce operational costs.
Scaling cabinet power
Current data centers typically supply 30-40kW per cabinet, but future configurations may exceed 200kW as CPUs and GPUs grow more powerful. For instance, Nvidia’s H100 AI accelerator operates at a thermal design power (TDP) of 700W, and next-gen models like the Blackwell B200 are expected to reach 1200W. Handling these power levels requires PDNs to address challenges such as managing high currents at low voltages, minimizing voltage drops and power losses, and implementing effective cooling solutions. Optimizing the PDN involves metrics like energy efficiency, power density, rack space utilization, and cost-effectiveness.
Why Intermediate Bus Architecture (IBA)?
Given the inefficiencies of direct high-to-low voltage conversion, data centers are increasingly adopting Intermediate Bus Architecture (IBA). This strategy divides DC/DC conversion into two stages, leveraging intermediate voltages to improve overall efficiency. For example, distributing power at 48V or 52-54V reduces current levels and minimizes resistive losses. In an IBA system, an Intermediate Bus Converter (IBC) handles the first stage of voltage reduction. These converters can be isolated or non-isolated, with recent advances favoring non-isolated designs due to their higher power densities and the requirement for isolation in the board-mounted DC/DC converters can be reduced, as the safety responsibility is shifted to the AC/DC power supply unit (PSU).
Innovative IBC solutions
Modern IBCs offer unprecedented power density and efficiency. For instance, Flex Power Modules’ BMR316 delivers 1kW of continuous power and up to 2.8kW of peak power in a package 80% smaller than traditional designs. This compactness enables AI-focused data centers to adopt non-isolated, unregulated IBCs for superior energy management.
Picture: BMR316
Fixed-ratio IBCs, like those with 4:1 or 8:1 conversion ratios, provide tailored solutions for specific system needs. For example, a 4:1 ratio yields higher power density and improved thermal performance whilst an 8:1 ratio is more suitable for lower input/output voltage differentials, balancing efficiency and current demands.
Advanced cooling techniques
As data center power density increases, traditional air-cooling methods fall short. Liquid cooling technologies such as Direct-to-Chip cooling from associate companies such as JetCool, and immersion cooling, are gaining traction. These solutions ensure efficient heat dissipation, critical for handling the thermal loads of compact, high-power components.
Vertical Power Delivery (VPD): A game-changer
To optimize space and performance, Vertical Power Delivery (VPD) integrates Voltage Regulator Modules (VRMs) directly below CPUs or GPUs. This design minimizes connection lengths, reduces power losses, and frees up valuable PCB space. By coupling VPD with IBA systems, data centers achieve even greater efficiency and flexibility.
Conclusion
Data centers face complex challenges in optimizing power delivery. Selecting the right IBC solution depends on system-specific factors, from voltage levels to thermal management. Considering electrical, thermal, and mechanical requirements, a holistic approach is key to achieving the ideal balance of performance and efficiency. For power engineers navigating these decisions, software design tools like Flex Power Designer can streamline the design process, ensuring tailored solutions for modern data center needs. With the right power architecture, the future of AI and cloud computing is not just powerful but sustainable.