“True 150W” AC/DC power supply in 2 x 4-in. format

June 29, 2015 // By Graham Prophet
XP Power’s EPL225 series power supplies offer up to 95% efficiency, delivering 150W convection-cooled or 225W with forced-air cooling, across their full temperature and voltage range without derating, from a standard 2 x 4-in. open-frame outline.

These high efficiency open frame AC-DC power supplies carry approvals for industrial, IT and medical applications. The series comprises seven single-output models that offer a range of standard output voltages from +12 VDC to +48 VDC. A secondary 12 VDC / 0.5 A fan output is provided across the range. The low-profile ‘1U’ footprint has a 1.26 in. (32.3 mm) profile making it, the company says, simple to integrate. The series has a convection-cooled output power rating of 150W which XP claims is best-available for a power supply of this footprint; “150W in that space is leading-technology,” an XP spokesman commented. Output power of up to 225W is available with 10 CFM of forced airflow.

The EPL225 series offers a minimum average efficiency of 93% and a maximum efficiency of 95% resulting in less heat to dissipate and a cooler running unit, the later contributing to a more reliable longer-life power supply. The units maintain efficiency down to low power levels, still performing at over 90% down to around 20% of full load. XP re-iterates the point that incremental gains in efficiency represent significant reductions in waste heat.

The supplies’ full output is available over the specified range of of 90-264VAC input; derating only applies if the line voltage drops below 90V, down to 80V. Similarly, the units operate over -20 to +70C with no derating until +50C. In practice, XP says, this simplifies a specification process where the designer initially requests a given size and power rating supply, but is compelled to move to a higher-rated, or larger, unit to ensure operation at the limits of voltage or temperature – this is the justification for XP’s description of the units as “true” 150W. The units’ “green” attributes include a no-load power consumption of less than 0.5W enabling compliance with the latest environmental goals and legislation.

The series meets the 5000m altitude operating specification and complies with the universal safety