What is the best topology for an offline SMPS 330W?

How about: Multiphase Cuk converter.

What is that?

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

A real easy design is to take a cheap, off-the-shelf class D amp chip, and put an oscillator in front of it to drive your output stage with a nice sine wave. Put a feedback loop in to push the "volume control".

Make a super clean, low ripple linear fed by what is technically a switcher inside the amp chip. Even if you only run it at like 17kHz, the chip is at like 400kHz sample rate inside. This 'noise' can be detected in your output if not managed properly.

Don't too many Cuks spoil the broth ?:-)

...Jim Thompson

I thought it was pronounced chewk. Rhymes with puke.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

The reason I ask is that I'm taking a trip at the end of the month and where I'm going there will be a lot of places were I can get Ferrite cores. Who knows if I'm nice they may even wind up an ETD39 or 44 transformers for a half bridge. After some reading that is the best topology for the power range.

I can pick up an assortment of cores for 50 to 150W range while I'm at it.

Or perhaps 3, but yes running multiple Cuks out of step was what I was suggesting as another way to go.

The ideal transformer coupled Cuk converter can be made to have no input or output ripple. It is still useful to consider making more than one section and putting them in parallel.

I've noticed that most controller ICs seem to be for non-cuk topologies. (Or perhaps it can be used but Cuk is not mentioned.) By any chance you know a nice controller chip for a Cuk supply? I need a supply that can vary from 10% to 80% duty.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

I thought it rhymed with "buck", a la, one rev. higher than a Buck is a Cuk. ;-)

Cheers! Rich

I think I remember now.. I think Cuk is pronounced 'Chook'. Rhymes with book.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Sheeeesh! I was only trying to be a little funny ;-)

...Jim Thompson

Cuk-a-doodle-do.

It appears that google lost my earlier reply Booster chips. Lets see if this works.

Ok it worked.

Nearly any of the booster chips will work as the controller for a Cuk converter if you get the voltage feedback right.

Even an oldish design like an LT1246 will work.

I'll check'm out. Thanks

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Four higher is what you would like.