Electronics Weekly
“This is the most efficient power supply of its kind on the market,” sales director Steve Elliott told Electronics Weekly. “It is 93% efficient even at 90V in. There really is nothing around in the market at this size that is convection cooled.”
The open frame unit, dubbed CCM250, is 152x101x39mm and only has to dissipate 13W.
To hit this efficiency mark, XP has used a three-stage topology.
The first stage is a variable frequency resonant boost power factor corrector that produces 380V.
The last stage is a crystal-controlled fixed frequency – 51.2kHz – zero-current-switched (ZCS) resonant interleaved two-phase half-bridge. The output uses synchronous rectification.
“Providing the frequency is very well controlled, you can ensure the mosfets always switch at zero current,” said Elliott.
Fixed frequency ZCS means that this stage is unregulated, which is why an intermediate stage is needed.
The middle stage is a boost converter that produces between 380 and 420V to regulate the output.
Fixed outputs between 12 and 48V are available.
Applications are expected in the medical, IT and industrial sectors.
XP claims that fan-less operation is increasingly sought in bed-side equipment. “Avoiding audible noise is particularly important in medical applications, where it disturbs patients,” said the firm, adding: “Both conducted and radiated emissions are below Class B limits as defined by EN55011, another important consideration in achieving type approval for medical equipment.”
The power supply delivers full output with convection cooling over input voltages from 90 to 275VAC, and 200 Watts from 80VAC, in ambient temperatures of -10 to +50C.
Where short-term peak power is needed, for example for motor start-up, it will deliver 300W for 500ms.
Remote shut-down is provided, as is a 5V stand-by rail.
Standby power consumption is above 0.5W.
