Infineon Fuses the Power of Si, SiC, and GaN in New Power Supply Units
With the goal of decarbonizing AI server racks, the new series of power supply units (PSUs) focus on efficiency, ranging from 3 kW to 12 kW.
Infineon Technologies recently introduced a new range of advanced power supply units (PSUs) specifically designed for AI data centers. These PSUs, ranging from 3 kW to 12 kW, leverage new semiconductor technologies to achieve extremely high efficiencies.
Included in the expanded PSU offerings is the "world's first 12 kW power supply unit".
A Closer Look at Infineon’s 8-kW AI PSU
To better understand Infineon's solutions, let’s examine the 8-kW PSU solution specifically.
This PSU uses a hybrid switch approach, integrating three types of semiconductors: silicon carbide (SiC), gallium nitride (GaN), and silicon. Each material is strategically included to optimize performance. SiC is used in the bridgeless totem-pole power factor correction (PFC) for its lower temperature coefficient of RDS(on), enhancing efficiency at high temperatures. GaN transistors are used in the high-frequency full-bridge resonant converter (LLC) because of their lower capacitances, enabling higher switching frequencies and improved power density. Silicon devices are employed where switching losses are minimal, providing low RDS(on).
Functional blocks of the 8-kW PSU solution.
Key components include CoolSiC MOSFETs (650 V), CoolGaN transistors (650 V), CoolMOS 8 SJ MOSFETs (600 V), CoolSiC Schottky diodes (650 V), and OptiMOS 5 power MOSFETs (80 V). Additionally, digital isolators (ISOFACE) and various EiceDRIVER components contribute to the PSU's high performance and safety.
Efficiency
Achieving a benchmark efficiency of 98%, the PSU reduces cooling requirements and improves overall system reliability. It boasts a high power density of 100 W/in³, twice the ORv3 specification, contributing to its compact form factor and suitability for modern AI rack infrastructure. Operating with a single-phase high-line grid input ranging from 180 VAC to 305 VAC, the PSU outputs a nominal 50 VDC. It can deliver up to 160 A, resulting in a maximum output power of 8 kW, sufficient for power-intensive AI applications.
Power Management
Featuring full digital control for both the interleaved bridgeless totem pole PFC and the full-bridge LLC, the unit enhances precision and flexibility in power management, ensuring optimal performance under varying load conditions. The proprietary and integrated magnetics design further optimizes the PSU's efficiency and performance. To comply with strict hold-up time requirements while maintaining high power density, the PSU incorporates an auxiliary boost circuit. This circuit capitalizes on the intermediate energy storage, reduces the need for bulky capacitors, and enhances system reliability.
Addressing AI Concerns
As AI workloads account for a larger portion of data center computing, developers need more highly performant and efficient power supplies. With a hybrid switch approach that judiciously leverages the benefits of silicon, SiC, and GaN all within the same device, Infineon’s new suite of AI PSUs is a step toward tackling this problem. This solution scales with the growing energy needs of AI applications, allowing data centers to freely adapt to future demands while maintaining energy efficiency and reducing environmental impact.
All images used courtesy of Infineon.
