Maker Pro
Maker Pro

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

H

Hammy

90VAC to 140VAC INPUT, 33Vdc out 10A.

Half-Bridge Push-Pull Converter or two switch forward.
 
A

Archimedes' Lever

How about:
Multiphase Cuk converter.


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.
 
H

Hammy

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.

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.
 
M

MooseFET

What is that?
2 Cuks with opposing ripple?

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.
 
R

Rich Grise

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

Cheers!
Rich
 
M

MooseFET

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.

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

MooseFET

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.
 
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