400W front-end AC/DC modules maximise power density

January 06, 2016 // By Graham Prophet
Vicor has added to its range of high density AC-to-DC front-end modules with isolation and power factor correction, packaged in a chassis-mountable module format, and providing up to 400W of isolated 24 or 48 VDC.

These PFM AC-DC front-end modules use Vicor’s VIA package, maximising cooling performance and versatility in converter mounting. They have universal AC input (85 – 264 VAC), power factor correction, and a fully isolated 24 VDC or 48 VDC output, and deliver 400W of isolated, regulated, DC output power at efficiencies up to 93%. This equates to 127 W/in³ (8 W/cm³) in the 9 mm profile VIA package, for use in industrial, process control, telecommunications, office equipment, test and measurement, LED lighting and other “off-line” applications.

These new units integrate a full range of front-end functions required by contemporary AC line-operated power systems -- transient and inrush current protection; input power factor correction; input to output isolation; and a regulated SELV (Safety Extra Low Voltage) DC output -- and meet international safety and regulatory agency standards for isolation, conducted emissions, power factor correction, and susceptibility to AC line transients, flicker, interruptions and surges. VIA package configurations are available for both on-board mounting and chassis mounting and units are available in two operating temperature ranges.

In many applications, Vicor adds, a user can instantly implement a complete AC-DC front end by simply combining a PFM with an AIM (Universal AC Input Module), which integrates all required primary-side rectification, filtering and transient protection circuitry) – both in VIA packages – and adding suitable secondary-side storage capacitance. Alternatively, a designer can combine a PFM front-end module with rectification, filtering and secondary-side output capacitance that is optimised for a specific application.

In either case, the PFM front-end module offers a quick and easy pathway to a rugged, high-performance, high-density AC-DC front-end solution, while eliminating the uncertainties and long design cycles associated with a custom front-end design. And, whereas many alternative front end systems are configured with capacitive energy storage at the high-voltage input, the PFM offers enhanced system safety by storing energy in low voltage capacitors at the isolated SELV output.
At one-fifth the thickness of traditional “1U” front-end solutions, the VIA package simplifies mounting to an equipment side panel, chassis or other external heat sinking device and provides improved thermal performance. Moving the AC-DC conversion function to a chassis or side panel can reduce system size and cost, or free up valuable system real estate for other uses, and can provide improved thermal performance while eliminating the need for, and cost of, external heat sinks.