Non-isolated unregulated intermediate bus converters are widely used in modern computing and networking equipment. This was only accelerated after cloud systems and AI started gaining traction, where these modules are used for their power efficiency and simple design. Namely, because the input and output in non-isolated converters share a common ground, they are power-dense and efficient, making them the preferred choice for data centers.
Flex Power Modules, a leading manufacturer of board-mounted DC/DC converters, just introduced a new model that takes the efficiency game to a whole new level. Called the BMR323, this non-isolated, unregulated Intermediate Bus Converter (IBC) promises a significant punch in a compact form factor.
Housed in a tiny 27 x 18 x 6.7 mm (1.06 x 0.71 x 0.26 in) package, the BMR323 delivers 600W of continuous power. It can handle 1200W bursts, too. This translates into an impressive power density of 368 W/cm³, making it one of the most space-efficient power converters in its class.
The converter operates on a fixed 8:1 ratio, meaning its output voltage ranges from 5V to 7.5V depending on the input (which must be between 40V and 60V). While the output isn’t regulated, this kind of setup is ideal in applications where downstream power stages — such as POLs (Point-of-Load converters), VPDs, or VRMs like the BMR510 — perform final voltage regulation. This approach helps optimize overall system efficiency, especially in server and networking equipment.
Still, it’s efficiency where the BMR323 really shines. With peak conversion efficiency reaching 97.8%, it minimizes energy waste and thermal output — two critical factors in densely packed electronic systems. Need more power? The design supports paralleling up to six units, reaching an aggregate output of 3600W.
Flex has also paid careful attention to thermal design. The BMR323 is optimized for top-side cooling, making it compatible with heatsinks and airflow systems. Alternatively, its flat topside allows for effective liquid cooling via thermal blocks and gap pads, providing flexibility depending on the cooling strategy.
In addition to robust thermal performance, the BMR323 comes equipped with key protection features: output current limiting, over-voltage protection, over-temperature shutdown, and input under-voltage lockout. For added control and visibility, a PMBus® interface is integrated for real-time monitoring, configuration, and diagnostics.
Designers can also leverage the Flex Power Designer Tool, which simplifies the integration of the BMR323 into larger power management systems. As expected, the module is fully compliant with IEC/EN/UL 62368-1 safety standards, ensuring reliability in industrial and telecom-grade environments.
