3U form-factor PSU offers increased power benefits

May 23, 2012 // By Paul Buckley
Pulse Electronics' 3U form-factor PSU for VPX applications is now available with optimized Positronic P47 connections and can be configured to deliver more than 400 W of power plus provide an additional high power 28 V protected output.

Pulse Electronics' 3U form-factor power supply unit (PSU) is now available with optimised Positronic P47 connections allowing delivery of more than 400 W of power.

The PSU, which is intended for military and aerospace VPX-based applications, comprises a number of Pulse Electronics’ high-reliability, planar technology power modules and can be configured to have up to five DC outputs. For example, one configuration might be: +12 V, -12 V, +5 V, +3.3 V and an auxiliary +3.3 V; all referenced to a common 0 V.

Of these output voltages, +12 V tends to be the one of which the highest power and current are now demanded, rather than the historic high current outputs for either the 5 V or 3V3, in light of the trend to down-regulate closer to processors. Through the use of optimised P47 connections, and feeding out on up to four pins rather than the single pin, some 25 A (i.e. 300 W) of peak power can be provided on the +12 V output.
 
The use of P47 connections also means the PSU can be configured to provide a 28 V protected output (rated up to 320 W). This can be used as a filtered power feed to heaters, to warm the VPX rack box when operating at low temperature extremes, or used unfiltered for powering cooling fans. Again this is only available by using an optimised pin configuration associated with the P47 connector.

The PSU’s input is a nominal 28 VDC, though its input steady state is compliant with RTCA DO-160E A(CF) – i.e. 22 to 30.3 VDC – and therefore also compliant with MIL-STD-704F (22 to 29 VDC). The unit can also be configured to be compliant with MIL-STD-1275B and DEF STAN 59-41.1 land Class ‘A’.

The modules also cope with the high transient voltage ride-through requirements of DEF STAN 61.5 part 6 issue 6 (175 V for 350 mS), which again infers input voltage