MIL-COTS Bus Converter Module Reduces System Size and Weight

June 25, 2011

Military aircraft and ships typically use an isolated 270 VDC power distribution system, specified to MIL-STD-740E/F. However the equipment it supplies, such as radar, processors, radio, satellite and GPS all requires lower regulated or unregulated DC voltages. Vicor’s new high-efficiency, non-regulated MIL-COTS BCM bus converter MBCM270F450M270A00 operates from 270 VDC power and is fully MIL-STD-740E/F compliant. It provides a nominal 45 VDC output with better than 96% efficiency and over 800 W/in³ power density.

Minimising equipment size and weight, while maintaining power capacity, is always a primary concern within mobile military applications, whether air, sea or land based. The MBCM270, which weighs just 14.5 g and has a profile of less than 7 mm, can be used either alone or as part of a power train. The resulting small, efficient and lightweight systems have sufficient power to drive the end application. Its proprietary Sine Amplitude Converter (SAC) topology employs an isolated DC-DC transformer, high-frequency switching for reduced size, and a ZCS, ZVS technique for low noise. SACs offer over 4 kV isolation and can also be paralleled for high power arrays.

Application-specific power trains comprising the MBCM270 bus converters, together with downstream PRM Regulators and VTM Current Multipliers, can power computing-intensive applications such as airborne servers or communications and monitoring systems. These require a range of POL regulated and unregulated supplies at various voltage and current ratings. Radar systems pose a different challenge by placing a high power ‘pulsed-load’ demand on the power system. The MBMC270 can trickle charge a capacitor bank, which can then discharge a peak power pulse through a downstream bus converter module. The power train design facilitates the use of smaller, lighter and more reliable discharge capacitors.

Systems based on the MBCM270, through a 3% improvement in efficiency, operate with half the power loss of earlier designs. This means a 50% reduction in fans, heatsinks and coldplates. Additionally, the BCM’s high frequency switching allows smaller, lighter filters. These factors, together with the MBCM270’s reduced dimensions, contribute to a significant reduction in system size and weight. Systems that have a 60% smaller footprint and a 66% weight saving become possible.

The MBCM270 is available with either a 45 VDC or a 28 VDC nominal output. It can deliver 350 W across a case temperature range of -55˚C to +85˚C, or 270 W across -55˚C to +100˚C. A transient power capability of 200%, or 540 W, for 10 mS is also available. Packaging options include SMT V·I Chip Module, Through-hole V·I Chip Module and thermally enhanced VI Brick Module. This MIL-COTS BCM device completes a family of V·I Chip power components designed for military mobile environments.

For datasheet CLICK HERE


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