AC-DC brick packs 54 W/in3 into a small space

Nov. 19, 2012
The VI Brick AC Front End module is a complete AC/DC converter operating over 85-264Vac to deliver a fully isolated and PFC regulated 48-V output.

The VI Brick ac Front End module is a complete ac–dc converter which operates over the universal ac input range of 85 to 264 V delivering a fully isolated and PFC-regulated 48-V output.

In a low profile package measuring 3.75x1.91 in (95.3x48.6 mm) and 0.38 in (9.55 mm) high, the ac Front End module provides a power conversion density of 121 W/in3 (7.5 W/cm3) or 54 W/in3 for a complete supply that includes all necessary components including hold-up capacitance.

Developed by Vicor, the ac Front End module is said to simplify the design of a complete front end system that meets IEC 61000-3-2 harmonic noise and Class B EMI conducted emission limits supplying 330 W to external output storage capacitance. The Module uses a proprietary Double-Clamp ZVS high switching frequency topology to yield efficiencies of up to 92% across the ac input voltage range, including operation down to 85 Vac and cuts power losses by more than 50% compared to competing offerings, according to Vicor.

The new VI Brick ac Front End module is compatible with numerous downstream dc–dc power conversion components. The VI Brick ac Front End modules will be available in consumer (-20°C to 100°C), telecom (-40°C to 100°C) and military (-55°C to 100°C) temperature grades.

Vicor has also developed higher power versions of its VI Chip PRM non-isolated voltage regulators. The regulators deliver up to 500 W at twice the power density of previous generation modules.

The firm's Factorized Power Architecture (FPA) separates, or ‘factorizes’, regulation and voltage transformation functions into building blocks. PRM modules accept an unregulated input voltage and produce a regulated output; VI Chip VTM Current Multipliers provide isolation and voltage and current transformation. Together, they convert an unregulated 48-V bus to as low as 0.5 Vdc.

Incorporating an advanced version of the firm's proprietary high-frequency ZVS buck-boost technology, the new PRM modules can deliver up to 500 W at over 97% efficiency, at power densities of up to 1,700 W/in3 (103 W/cm3). Models are available in both full-chip and half-chip packages, with input voltage ranges of both 36-75 V and 38-55 V, and can generate an isolated 0.5 V to 55 Vdc output when used with VTM current multipliers.

The firm has also developed 14 new additions to its PI33XX Picor Cool-Power ZVS buck regulator product line for high efficiency point of load dc-dc regulation. This product line extension includes higher current devices and optional I2C fault telemetry and programmability. The PI33XX products are designed to convert 8 to 36-V inputs to high current, low voltage point-of-load system rails such as 3.3, 2.5, 1.8 and 1 V, and deliver advanced power management functions.

The PI33XX series can support high-performance conversions with large step-down ratios up to the rated input voltage of 36 V. All products in the PI33XX series are highly integrated with control circuitry, power semiconductors and support components in a 10x14x2.56-mm LGA System in Package (SiP). Power delivery can be further increased by interleaving multiple Cool-Power ZVS buck regulators using single-wire current sharing without the need for any additional components.

Picor PI33XX-01-LGIZ Cool-Power ZVS buck regulators are priced at $15.41 for 1,000-unit quantities. Optional I2C devices, PI33XX-20-LGIZ and PI33XX-21-LGIZ are priced at $14.13 and $16.96 for 1,000-unit quantities, respectively.

Vicor Corp.,


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