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Which topology for 400w

I have to design a converter for 400w. input voltage is 20-32 and output is along similar lines and is variable - under the micros command. Current is about 15amps, and supply has to be clean. I'll be getting into the project next week and I thought I would run it up the SED flagpole.

A buck-boost converter was tried using one inductor. When the commanded output voltage was near the input voltage the power supply would be in a zone where it was switching back and forth between buck and boost modes and there was some unfilterable lower frequency noise spurs showing up.

Supply obviously doesn't have to be isolated but I think a pair of interleaved forward converters might be a nice way to go. Other prospects are a single forward with maybe an active clamp type of reset. Other possibility would be seperate boost and buck controllers in series with maybe a pic to supervise them.

Profile is very short and I have a heatsink to work with so I'm thinking TO-220s on a copper plate with the board resting on top and planar magnetics. Maybe one of those Berquist boards that are bonded to an aluminum plate might work too. I have a decent heatsink to bolt the module to.

So I'm interested to hear comments on why one topology might be better than another.

Regards, Bob N9NEO

Reply to
Yzordderrex
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Come on now fellas, lets get this project started on the right foot. I tell my boss I've assembled one of the finest design teams in the world. He expects results. I've probably rambled on and given way too much information in my OP. My bad. Just pick me out a converter then and I'll do the rest.

Kind regards, NEO

Reply to
Yzordderrex

I like the one inductor BB (Buck Boost topology). You have complete control of input current, output current and voltage. Inductor always clamped to both rails so no snubbers needed. All semi voltages inside the rails and there are some great 55V MOSFETS and Schottky diodes. Only one magnetic needed for complete design. Heat spread over four MOSFETS for good heat spreading. Only drawback is both input and output currents are discontinuous so interleaving two channels would be sick, as in sweet! What is not to like? Ok, so you hate the topology because you had a problem and couldn't fix it. You can't publish the schematic so we can fix it because it is propriety information. So changing topologies will fix all problems. What control chip did you use for the BB? The better ones have robust hystersis for changing modes. Cheers, Harry

Reply to
Harry Dellamano

So you ask for help, I try to give you help but you don't answer! Why should we try to help you? Harry

Reply to
Harry Dellamano

The "Watts" designator is ALWAYS capitalized.

Reply to
Spurious Response

No it isn't. You've quoted a case where it wasn't.

Reply to
MooseFET

Watt (James) is a person's name and must be capitalized. Harry

Reply to
Harry Dellamano

It is also a unit of measure and thus *should* be capitalized. That is a different thing from *always*. I guess I should have added the :)

Reply to
MooseFET

Sorry Harry. I am moving a few hundred miles this week - furniture, cars, pets and so forth. My computer is packed up and I am now at in- laws house. I have been mulling over your first reply and I will get back to the group early next week. I would like to hear of more robust controllers. Sorry to the others who are concerned about the little w I used, and I agree that it should be capitol or perhaps it is capital. Heheh.

Later, Yzordderrex

Reply to
Yzordderrex

Wrong, dipshit. The electrical term for power is a capital W.

A lower case w is not an electrical term for power.

Reply to
Spurious Response

It has absolutely NOTHING to do with the fact that it is a "unit of measure" either, as there are several "units of measure" which do not follow your ill claimed rule.

THIS PARTICULAR unit of measure, however, IS always capitalized.

Reply to
Spurious Response

Once again you get it wrong. The very person you are complaining about didn't capitalize the "w". How can you say "something IS always done" when you quite the counter example? You can say it *should* always be done but that isn't what you said.

Reply to
MooseFET

LOL

Reply to
MooseFET

LOL!

"W" chould be capital "watts" lower-case. Bye. Jasen

Reply to
Jasen Betts

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