25 June 2009
High efficiency ac/dc converter targeted at medical applications
XP Power has launched the CCM250, a 250W ac/dc power supply which is said to achieve up to 95% efficiency. According to the company, this is 5% better than the efficiency of similar products.
Sales director Steve Elliott noted the product addressed three challenges: reducing the amount of energy wasted; making the device smaller; and removing the need for cooling fans.
"The starting point is to have a low loss switching stage," he noted. "The CCM250 uses a three stage interleaved resonant topology, which enables low switching loss. Mosfets are switched when the current is at zero, reducing transformer losses to less than 50%."
The device delivers its full output with convection cooling from inputs ranging from 90 to 275V ac. It can also deliver 200W from an 80V ac supply in ambient temperatures ranging from -10 to 50°C.
With a footprint of 6 x 4in and a height of 1.54in, XP says the supply is one of the smallest products of its type and suited to 1U enclosures.
"Synchronous rectification means we can replace diodes with mosfets," Elliott continued, "and lower losses mean smaller capacitors can be used."
A target application is medical devices. Elliott pointed out that space is at a premium in such applications, while ventilations is often not an option as manufacturers need to protect against contamination. "That means they need a small product with no fan and we wouldn't have been able to do this without achieving 95% efficiency."
Other applications will include industrial systems, where the wide input voltage range will help to cope with brownouts and voltage surges.
Author
Graham Pitcher
Supporting Information
Websites
http://www.xppower.com
Companies
XP Power
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