GaNの話

By Alex Lidow, CEO, Efficient Power Conversion,
Alejandro Pozo, Director of Applications Engineering, Efficient Power Conversion,
Ionel “Dan” Jitaru, CEO, Rompower Energy Systems

The industry shift toward 800 V_DC power distribution for AI server racks requires novel DC-DC converter architectures to optimize delivery. Because of its superior efficiency and power density, the Input-Series-Output-Parallel (ISOP) topology is rapidly becoming the standard. This paper analyzes three 800 V-input ISOP converters tailored for 50 V, 12 V, and 6 V nominal output rails. Implementing gallium nitride (GaN) transistors on both the primary and secondary switching sides enables these converters to establish new performance benchmarks for peak and full-load efficiency at each critical voltage node.

This technical article analyzes the design and performance of the EPCSC401 demonstration board, evaluating its radiation tolerance, thermal efficiency, and high-frequency switching topology.

Aerospace power system design faces a growing demand for power density and efficiency that exceeds the physical limits of traditional silicon MOSFETs, whose thermal losses and restricted switching frequencies heavily penalize payload weight. Consequently, GaN technology emerges as a disruptive necessity for NewSpace architectures, thanks to its wider bandgap and superior electron mobility. The EPCSC401 demonstration board facilitates this transition, allowing engineers to evaluate synchronous GaN power stages under extreme radiation conditions.

Gallium nitride (GaN) is changing the way engineers approach power conversion, enabling higher switching frequencies, greater efficiency, and higher power density than conventional silicon MOSFETs in many applications. But where does GaN really outperform silicon, and when does it make engineering and economic sense to adopt it? In the first episode of EPC GaN Q&A LIVE, EPC CEO Alex Lidow answers engineers' questions about GaN versus silicon, covering voltage ranges, switching losses, power density, transient response, PCB layout, parasitic inductance, gate drive, reliability, cost, and the comparison with silicon carbide. The discussion provides practical guidance for engineers evaluating GaN for next-generation power conversion systems.

The increasing adoption of 800 V power distribution in AI data centers and industrial automation is creating a new challenge for power-conversion designers: how to convert high-voltage DC efficiently into the 6 V, 12 V and 48 Vrails required by modern loads while maintaining high power density.

A presentation by Michael de Rooij of Efficient Power Conversion (EPC) examines how a multi-stage Input Series, Output Parallel (ISOP) architecture can distribute the high-voltage input across several conversion modules, enabling low-voltage GaN FETs to be used on both the primary and secondary sides of multi-kilowatt isolated converters.

At PCIM Asia 2026, EPC presented its Gen 8 monolithic GaN power stage for AI processor power delivery.

Developed by EPC for high-frequency multiphase POL / IVR applications on next-generation AI processors, Gen 8 integrates half-bridge power switches, high-speed gate drivers, bootstrap circuitry, level shifting, and logic on the same GaN die. With lower charge, faster switching, and stronger overvoltage capability, it targets operation from a 6 V input at frequencies approaching the 10 MHz class. The system-level significance is not simply a lower component count: integration reduces drive-loop parasitics and noise sensitivity, while allowing the control side to use high-speed processes better suited to extensive digital functionality, enabling more phases and denser processor-side placement.

Modern data centers’ power requirements are changing dramatically due to the rapid growth of AI workloads. As GPU platforms such as NVIDIA’s Vera Rubin push rack power from 200 kW toward the 1-MW level, traditional 48-V busbar power distribution becomes physically and economically impractical because of massive conduction losses. Current can exceed 4,000 A in the 48-V busbar before reaching the server boards.

To address these increasing current levels, the industry is transitioning to an 800-Vdc power distribution architecture. This approach enables high-voltage dc to be delivered directly to server boards, significantly increasing power capacity while reducing copper requirements and improving overall efficiency. One of the major challenges in the new 800-V ecosystem is the efficient conversion of high-voltage dc to the intermediate bus voltages of 12.5 V or 6 V required by POL voltage regulators powering AI processors, without needing an additional 800-V to 48-V conversion stage. Traditional single-stage topologies with such high stepdown ratios result in transformer complexity and limited efficiency.

This presentation showcases EPC’s latest gallium nitride motor drive ICs for high power, ultra compact applications. We first introduce the EPC33110, a 100 V, 20 Arms three phase motor drive demonstrated on an embedded board. We then preview the EPC33111, an 80 V monolithic three phase inverter in a 3.3 mm × 3.3 mm chip, integrated four up on a 2 cm × 2 cm board. Driving a quadcopter’s four motors with sensorless control, this design targets the world’s smallest, high density motor drive solutions.

GaN FETs, like any other form of transistor, dissipate power during switching, which manifests in the form of heat and can damage these devices if specific limits are exceeded. Heat management is therefore an important part of converter design.

In some applications, thermal management strategies are limited to solutions that can be implemented using only the PCB. Several effective board-level design techniques can be employed to maximise heat dissipation and improve GaN devices’ thermal performance without the use of a heatsink.

Artificial intelligence is pushing data-center power architectures into territory they were never designed to handle. As AI accelerators become more powerful, rack power is moving from tens of kilowatts toward hundreds of kilowatts and, ultimately, the 1 MW range. At that scale, delivering electricity efficiently is no longer simply a matter of selecting better power components. It becomes a system-level architectural challenge.

One of the most significant responses is the move toward 800 VDC distribution. NVIDIA is developing an 800 VDC architecture intended to support 1 MW-class racks and beyond, while large AI infrastructure projects are driving demand for power capacity measured in multiple gigawatts.

Gallium nitride (GaN) is entering a new phase of development. After establishing itself in applications such as lidar, satellite power, fast chargers, and AI power delivery, the technology is increasingly moving toward lower-voltage, higher-current applications where switching speed, low conduction losses and power density are critical.

For Efficient Power Conversion (EPC), this transition is particularly important. The company has built its GaN portfolio around enhancement-mode eGaN® technology and has consistently pushed GaN into applications where conventional silicon MOSFETs face limitations in switching performance, size and efficiency. The development of low-voltage devices below 100 V now opens additional opportunities in AI power delivery, robotics, motor drives and other high-current systems.