DC transformer

formatting link

Read carefully. It seems I have always underestimated the technological progress... :-)

Best regards, Piotr

Reply to
Piotr Wyderski
Loading thread data ...

I think they forgot the "m". 350mW?

Reply to
edward.ming.lee

A common shorthand, what they mean is for a typical (probably [active clamp] flyback or the like) topology with that as the DC supply.

Digi-Key's catalog shows a similar shorthand on hundreds of parts.

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Design 
 Click to see the full signature
Reply to
Tim Williams

And a generous interpretation indeed of "planar" IMHO.

--
This message may be freely reproduced without limit or charge only via  
the Usenet protocol. Reproduction in whole or part through other  
 Click to see the full signature
Reply to
Cursitor Doom

No. These planar transformers are impressive.

Coilcraft has planars up to 800 watts.

formatting link

--
John Larkin         Highland Technology, Inc 

lunatic fringe electronics
 Click to see the full signature
Reply to
jlarkin

Probably forward converter, which doesn't have to store energy so allows a small core.

--
John Larkin         Highland Technology, Inc 

lunatic fringe electronics
 Click to see the full signature
Reply to
jlarkin

The windings are planar, namely PC boards,

One can build transformers like this with the windings part of the main power supply PCB.

--
John Larkin         Highland Technology, Inc 

lunatic fringe electronics
 Click to see the full signature
Reply to
jlarkin

snipped-for-privacy@highlandsniptechnology.com wrote in news: snipped-for-privacy@4ax.com:

Just use an Archimedean spiral and one can even pair up the windings if it is low voltage.

Reply to
DecadentLinuxUserNumeroUno

No, the largest type are 350W max, but only with a heat sink (PCB with Aluminum substrate). That one has two "planar" PCBs with the turns. The smallest 40W version has only one PCB with both primary and secondary turns. Payton calls them planar, even tho they mount above your PCB, 14mm high in the case of the 350-watt version.

--
 Thanks, 
    - Win
Reply to
Winfield Hill

Winfield Hill wrote in news: snipped-for-privacy@drn.newsguy.com:

'Planar' in transformer nomenclature, used to refer to how the winding is arrayed. Not so much 'co-planar' to the PCB, but each turn in the same plane.

Reply to
DecadentLinuxUserNumeroUno

"Up to 350W planar transformers" clearly boasts the *transformers* themselves are planar, John.

Not relevant in this instance.

--
This message may be freely reproduced without limit or charge only via  
the Usenet protocol. Reproduction in whole or part through other  
 Click to see the full signature
Reply to
Cursitor Doom

Does it? The industry refers to this construction as a planar transformer. Google it.

formatting link

But "boast" ? In lowercase grey type? They are, among other things, establishing a search target.

It might be to people who actually design electronics. You know, people who aren't hostile to having ideas.

I think I might try making a transmission-line transformer embedded in a multilayer PC board. They are usually a nuisance to make. I'll throw some test cases on my next multi-idea proto board.

The little Murata dc/dc converters that I like are all PCB construction, but with a ferrite toroid embedded inside the board, and windings a combination of traces and vias.

formatting link

--
John Larkin         Highland Technology, Inc 

lunatic fringe electronics
 Click to see the full signature
Reply to
jlarkin

Great! I look forward to seeing the pictures in due course.

--
This message may be freely reproduced without limit or charge only via  
the Usenet protocol. Reproduction in whole or part through other  
 Click to see the full signature
Reply to
Cursitor Doom

You do need to go to a specialist printed circuit board shop if you want to do it right. It needs a lot layers of of thin substrate and some very thick copper winding tracks if you want to fill even half of the winding window with copper.

The outer layers can get by thinner copper (which does allows narrower tracks).

--
Bill Sloman, Sydney
Reply to
Bill Sloman

Half!? Impossible from any fab I'm aware of. Fortunately the winding length is short and the heat transfer is good, so it's not a big deal to use high current density. 10% winding factor is good when you're talking planars, and it's really not very different from say a toroid winding, which has similar aspect ratios.

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Design 
 Click to see the full signature
Reply to
Tim Williams

t
y
g

use

ich

Perhaps. I spent half an hour at a trade show some years ago talking to a p rinted circuit guy who specialised in the business, and a couple of years a go we had thread here about a similar sort of firm. They could get the copp er layer thicker than the substrate.

It's certainly going to worth talking to somebody like that.

--
Bill Sloman, Sydney
Reply to
Bill Sloman

A buried strip-line should be non-dispersive - if you take the trouble to use a proper microwave substrate. It's not exactly an original idea.

You'd need X-rays to get a useful image.

--
Bill Sloman, Sydney
Reply to
Bill Sloman

The flat turns reduce skin loss, and some air can get in there to cool the windings.

--
John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
 Click to see the full signature
Reply to
John Larkin

It's certainly going to worth talking to somebody like that.

Wonder if it's more of a potting operation than lamination -- or if the result simply has voids; give or take what spec you order?

You can of course get more copper density within a given layer, by using wide traces, but you can't fill in those gaps with regular prepreg of inferior thickness.

Typical dimensions might be, like...

2oz/layer: ~2.8 mil copper, 7-10 mil prepreg. Fills in fine. Trace width/space minimum about 7 mils (some 8 or 10, some down to 5 or 4). Meager winding factor (~15%).

Heavy copper, say 12oz/layer: ~20 mil copper. 5-10 mil prepreg is just going to sit on top of it. Can't deposit copper that heavy on a flimsy core, either (so at least one dielectric layer has to be thicker). Apparently they need closer to 20 mil (as finished?) prepreg to fill in the gaps (and it's probably high-resin% prepreg at that?). Width/space about 30 mils, so you can't get many turns in a given area (should you happen to need them). Result, still a meager winding factor (~20%?).

But yeah, if someone can do thin prepreg + fill, and someone else can do vertical sidewalls (Lintek comes to mind?), the fill rate could get pretty amazing.

Actually that's even a bit concerning, simply because all the facing area (edges between adjacent turns), and the sharp corners, are going to make for wicked eddy currents / skin / proximity effect (whatever, all basically the same jumble of up-close AC effects).

I know! Bring back that laminated-wire-PCB technology and make printed litz windings! :^)

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Design 
 Click to see the full signature
Reply to
Tim Williams

At that power level it is more likely to be copper sheets, with a lacquer layer.

This datasheet for the same part, looks like copper sheets:

formatting link

Cheers

Klaus

Reply to
klaus.kragelund

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.