XP Power has launched the CHD250 AC/DC power supply series of ultra-efficient 250W convection cooled single-output units for applications that require medium power in an open-frame, fanless design. With a compact 3 x 5 inch standard footprint that fits within a 1U height, the series meets international safety approvals for industrial and medical equipment. The CHD250 series offers a low no-load power consumption of less than 0.5W. Featuring an almost flat efficiency curve over the entire load range, the series achieves an exceptional efficiency of between 93 and 94% typical at 230VAC and full load, assisting end customers in meeting energy saving criteria of new ‘green’ standards and minimising waste heat. In addition, the high efficiency allows the units to be convection-cooled, eliminating the need for cooling fans, making the series especially suitable for low audible noise requirements. The range comprises five models, providing output voltages of +12, 15, 24, 28 and 48VDC. Standard features include a power fail signal, output inhibit and remote sense, plus adjustment of the output voltage by the user of +5/-4%. To ensure that customers only pay for what they need, options for this series include a 5VDC / 0.5A standby output for powering memory or logic and a covered version. The CHD250 series meets IT 60950-1 and 3rd edition medical ANSI/AAMI ES60601-1 safety approvals (achieving 2 x MOPP), as well as EMC specifications EN55022/11 for class B conducted emissions. The supplies are capable of operating over a wide temperature range of -20C to +70C with no derating until +50C. The units need no U bracket or L bracket heatsink.