Second-generation direct DC/DC converter for data centers

11th June 2021

Flex

Alex Lynn

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Flex Power Modules has introduced the BMR482, its second generation of direct conversion isolated DC/DC converter. By converting directly from a 48V supply to the load voltage without an intermediate stage, the BMR482 delivers increased efficiency in a compact package, enabling it to meet the higher power needs of today’s data centers and cloud computing.

The BMR482 can achieve up to 91.3% efficiency with a 0.8V output at 53 Vin, which is two to three percent better than an equivalent solution based on an intermediate bus converter (IBC) and point of load (PoL). The single-stage BMR482 also requires up to 50% less board space than a conventional two-stage solution, helping reduce overall costs.

The new converter is available as a ‘main unit’, measuring just 30x12.7x16.8mm, which includes a digital interface for monitoring, configuration and control, and can deliver a maximum output current of 110A. If a higher output current is required, up to five ‘satellite’ modules can be added, measuring 30x12.7x15.4mm each, to provide a maximum total output current of 660A. These are automatically enabled and disabled by the main unit depending on the output current drawn, meaning efficiency is optimised across the entire current range dynamically.

Designed for server applications, the BMR482 has an input range of 40 to 60V, enabling it to operate with supplies nominally rated at 48 or 54V. It has a programmable 0.5 to 1.35V output voltage, and the main power train has 1,500V isolation from input to output.

The BMR482 is compliant with the PMBus v1.3, AVSBus and Intel SVID interfaces, offering complete digital control. It is supported by the Flex Power Designer software tool, making power system design easier and quicker.

The new converter provides a fast load transient response and high current monitoring accuracy. It offers excellent thermal performance and is designed with optimal cooling in terms of terminals, footprint and component placement. Reliability is critical in such applications, and the BMR482 offers a mean time between failure (MTBF) of over 13.1M hours.

Olle Hellgren, Director Product Management and Business Development at Flex Power Modules, said: “Today’s data centers are testing the limits of conventional IBC/PoL architectures, with up to 3kW or 4kW required per board. The BMR482 solves this problem by converting directly from the 48Vor 54V system bus voltage to the PoL voltage, which is typically less than two volts.”

The BMR482 will be available in July 2021, and samples are available now.