Wide Range DC to DC Converter

Aug 19, 2010 2 Replies

Hi There,



I have an application for a 500W DC to DC converter. The input is



15VDC-->60VDC and the output is 10VDC. I ran through some numbers and using a full bridge with ZVS I don't think I can get 90% eff at full load over the input range. Also the ripple and 60VDC input may be a problem too.

If I were to use a boost converter (CCM) before the full bridge can I get higher overall efficiency? I read a few posts and am a little confused. Lets say if boost to 80V first then use a full bridge to get from 80V to 10V. The boost would still have to deal with the wide input range of 15VDC->60VDC. However, I notice the transfer function is not linear, Vo = Vin (1/(1-d)) unlike the full bridge (CCM). Is the non linear transfer function the reason the CCM boost can handle wide input ranges with better eff than a full bridge or buck topology?


Kooner.


Push pull forward converter. Synchronous rectifier if higher efficiency is desired.

Full bridge has double losses no matter what you do.

Tim

-- Deep Friar: a very philosophical monk. Website:

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Do you need isolation? If not, it's just a buck regulator, maybe one of those newfangled polyphase ones.

John

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