Isolated DC/DC converter targets digital conversion

The BMR481 DC/DC converter has an input range of 40 to 60V for 48 to 54V nominal supplies, and a programmable 0.5 to 1.35V output. A main module, measuring 12 x 27.7mm, provides a maximum output current of 70A and has a digital interface for monitoring, configuration and control. This module can be supported by up to five additional satellite modules for a current rating of up to 420A.

Unlike a conventional two-stage intermediate bus converter (IBC) and point of load (PoL) architecture, no extra conversion step is required. The Direct Conversion module achieves up to 92% efficiency from a 1.0V output at 53V in. This, explains the company, is up to 3% higher than what an equivalent IBC-based deployment can deliver. It also allows a reduction in board area of up to 50%. MTBF for the main module is over 8.7Mhrs.    

Efficiency is optimised by automatic enabling and disabling of phases/satellite modules depending on the required load. Another characteristic is dynamic voltage adjustment to provide optimum supply rails to connected ICs. Output ripple and noise is typically just 1mV p-p, due to the zero voltage/zero current switching. Load and line regulation are typically kept to just 1mV. At 53V input and 0.5V output, the full 70A output current is available from the main module to over 75°C ambient temperature with 0.5m/s airflow and to over 90°C with just 2m/s airflow. Digital control is implemented with a PMBus v1.3 interface compliant with PMBus or AVS / SVID. Isolation is rated at 1500V DC (functional).

The BMR 481 is sampling now.