White Papers

VPX versus VME: The Power to Create More Powerful Systems.

By Jerry Hovdestad, Director COTS Engineering
Behlman Electronics

VME has been around since the 1980s and will continue to be used on various programs. As VPX technology grows, it is gradually replacing VMEbus in applications requiring very high speed switched fabric data transfer. The need for power supplies to keep up with the demands of such continuously evolving technology has always been a system design limitation, with power ceilings stalled for some time at 400-600 watts. This gating factor was due, at least in part, to the difficulty of cooling the high-density power supply cards essential for compliant profiles.

Network topologies based on the OpenVPX architecture enable multiple processors and multiple network switches to communicate efficiently and reduce R&D cost and risk. VPX is also highly compatible with VMEbus, and gives VMEbus users access to the high speed switch fabric.

Two facts are undeniable:

  1. If you have an OpenVPX™ system, you need a compliant power supply.
  2. If you need higher power ranges, they are now available.

Behlman currently offers three VPXtra™ high-power, high-efficiency, 6U power supply cards designed to support “OpenVPX Systems.” All the cards are designed to be compliant with ANSI VITA 62 which was released in June 2012.

Heat problems solved by Behlman’s Xtra-Cooling™ technology.

Behlman’s engineering breakthrough -- Xtra-Cooling™ technology -- has been achieved by unique card-edge conduction cooling that enables these power supplies to operate at full power up to a maximum rail temperature of 71°C. All cards are designed in accordance with VITA 46 Requirements; VITA 47 Environmental Considerations, and VITA 48 REDI, and are for use in VITA 65, Interoperability Specifications for VPX Systems.

Late in 2012, Behlman broke through the VPX power ceiling with its VPXtra™ 1000CD Power Supply. This unit is a high-power 12 V card that delivers a full 1000 watts of power at a typical efficiency of 91%. It is designed to be used in systems which require 12 V primary power. Multiple cards can be paralleled to deliver higher power to support as much current as modern backplanes require. This card also has a 3.3 V auxiliary output for system housekeeping functions. The input to the card is 28 VDC in accordance with MIL-STD-704 and MIL-STD-1275.

Behlman also offers the multiple output power card VPXtra™1000CM, for systems that require additional +5 V power as well as +12 V, 3.3 V and +/- 12 V AUX power. This card will produce up to 700 W of power at a typical efficiency of 88%, and can also run on +28 VDC.

The outputs of all Behlman cards can be paralleled with similar voltages of other cards to increase total system capability.

For systems that have an AC input, Behlman offers the VPXtra™1500. This card will take up to three phases of 115 VAC, from 47 to 440 HZ, in accordance with MIL-STD-704 and produce 1500 W of DC to drive our CD and CM models. The VPXtra™1500 has power factor correction and an efficiency of 92%. This high efficiency allows the card to be used at up to full power if the chassis cooling can handle the 130 W slot dissipation.

All Behlman VPXtra™ power cards are designed for a 1.0” pitch and have card ejectors which facilitate both insertion and extraction. Mechanically, they are designed to meet the shock, vibration, and humidity requirements of MIL-STD-810. Over-voltage, over-current, and over-temperature protections are included in the design. Circuitry is conformal coated for optimal humidity performance. They are also designed to meet the applicable sections of MIL-STD-461 for conducted emissions, conducted susceptibility, and radiated susceptibility. In accordance with MIL-HDBK-217F Notice 2, MTBFs are 336,000 for VPXtra™1000CM, 277,000 hours for VPXtra™1000CM, and 209,000 hours for VPXtra™1500.

All units incorporate Behlman’s Xtra-Reliable™ design and Xtra-Rugged™ construction. They are designed and manufactured to meet MIL-STD-810 for shock, vibration, and humidity, and MIL-STD-461 for EMI.