EPC Demonstrates 800 V To 12.5 V AI Power Converter Without 48 V Stage

Efficient Power Conversion (EPC) has provided additional details on the EPC91123 evaluation board, a 6 kW isolated DC-DC converter designed to convert 800 VDC directly to 12.5 VDC for next-generation AI server architectures. The board uses an input-series, output-parallel (ISOP) LLC topology and achieves up to 98.2% peak efficiency while eliminating the need for a traditional 48 V intermediate conversion stage.

The EPC91123 is a high-voltage DC-DC conversion platform intended for rack-level AI power systems. By converting directly from 800 VDC to 12.5 VDC, the board reduces the number of power conversion stages between incoming power and downstream computing hardware.

According to EPC, removing the intermediate 48 V rail can improve overall system efficiency by between one and two percentage points. While that may appear modest at first glance, efficiency gains become increasingly valuable as power levels continue rising across modern AI infrastructure.

Removing The 48 V Intermediate Rail

Many server power architectures rely on multiple conversion stages before power reaches processors, accelerators, and memory subsystems. The EPC91123 takes a different approach by converting directly from 800 VDC to 12.5 VDC in a single isolated stage. Reducing the number of conversion steps lowers cumulative conversion losses and simplifies part of the power delivery chain. The board forms part of EPC's wider work around 800 VDC distribution systems, which are receiving increasing attention as AI compute platforms continue scaling in power consumption. The company states that direct conversion can improve overall system efficiency while reducing distribution losses within the rack.

6 kW In A Compact Form Factor

The EPC91123 delivers up to 6 kW of output power while measuring 104 mm × 47 mm × 8 mm. At those dimensions, the board is intended for environments where available space is limited but power demand continues increasing. AI servers and accelerator platforms are placing growing pressure on power delivery systems, forcing designers to look for higher power density alongside efficiency improvements. EPC specifies 98.2% peak efficiency and 97% efficiency at full load. The converter is designed as an evaluation platform, allowing engineers to assess the performance of the architecture and supporting power devices before moving into production designs.

ISOP Topology And Gen7 GaN Devices

The board is built around an input-series, output-parallel LLC architecture. EPC notes that ISOP topologies are particularly well suited to high step-down-ratio conversion because they allow improved transformer utilization while supporting interleaved operation.

The EPC91123 also incorporates the company's latest Gen7 eGaN technology, including the EPC2366 and EPC2305 devices. The EPC2366 is a 40 V device with an on-resistance of 0.8 mΩ housed in a 3.3 mm × 2.6 mm package, while the EPC2305 is a 150 V device specified at 2.2 mΩ.

Part Of EPC's 800 VDC Roadmap

The EPC91123 forms part of a broader development effort covering 800 VDC conversion architectures for AI infrastructure. In addition to direct conversion to 12.5 VDC, EPC is also developing solutions targeting 48 VDC and 6 VDC outputs to support different server and rack-level power architectures.

The company is contributing these technologies to the NVIDIA MGX AI Factory ecosystem, where 800 VDC distribution is being explored as a route toward higher power density and improved efficiency in future accelerated computing platforms.

The EPC91123 evaluation board is available now as part of EPC's portfolio of GaN-based power conversion solutions.

Learn more and read the original announcement at www.epc-co.com

Technology Overview

The EPC91123 is a 6 kW isolated DC-DC converter evaluation board that converts 800 VDC directly to 12.5 VDC using an ISOP LLC topology. The design incorporates EPC's Gen7 eGaN devices, including the EPC2366 and EPC2305, and achieves up to 98.2% peak efficiency while eliminating the need for an intermediate 48 V conversion stage.

Frequently Asked Questions

What is the EPC91123 used for?

The EPC91123 is an evaluation board designed for AI server and data center power architectures that require efficient conversion from 800 VDC to low-voltage rails.

Why does the EPC91123 eliminate the 48 V stage?

The board converts directly from 800 VDC to 12.5 VDC, reducing the number of conversion stages and improving overall system efficiency.

Which GaN devices are used on the EPC91123?

The design uses EPC's Gen7 eGaN devices, including the EPC2366 and EPC2305 power transistors.