OPTOISOLATED DC-DC

Gentlemen, I was curious on any ideas of an opto dc-dc converter providing 20mA. Small footprint and heighth.. Any ideas? Please and Thank You.

VIN-8-16VDC VOUT 5VDC 20mA,

Reply to
Johnny5
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OPTO ??? what !!

dc-dc converters are all transformer based.

Digikey has 1W units with 5000V isolation, they work just fine.

hamilton

Reply to
hamilton

Do you mean LED to PV? The ones you can buy deliver ballpark 100 microwatts at insanely low efficiency. They can be very handy for things like slow fet gate drives, like making your own SSR.

There are some serious laser+fiber+PV power delivery things, but they cost kilobucks.

If a laser were 50% efficient and a PV was 15% and you lost 20% from optics, overall efficiency becomes 6%. And it would be hard to do that well.

Little transformer-based potted dc/dc bricks start around $4. Murata and CUI make nice ones. They run around 85% efficient. I tested some of both recently and was impressed.

There is of course my Groucho Marx generator circuit, which uses optoisolated SSRs to make a sort-of-isolated power coupler. It can do watts at high efficiency and is relatively quiet.

John

Reply to
John Larkin

"Johnny5" Gentlemen, I was curious on any ideas of an opto dc-dc converter

** Ever though of using solar cells and a 12 volt lamp ??

.... Phil

Reply to
Phil Allison

Done carefully, that might approach 1% efficiency.

John

Reply to
John Larkin

... and go PHUT after a few thousand hours, requiring a quick trip to the autoparts store.

--
Regards, Joerg

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Reply to
Joerg

Even that I'd try to power magnetically through some porcelain or glass insulation.

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Reply to
Joerg

It's certainly possible (since you don't specify efficiency), but it probably would cost in the thousands of dollars. JDS Uniphase might be a place to start. It could well be a practical solution for such challenging problems as powering instrumentation that's at 100's of kV potential relative to ground.

Reply to
Spehro Pefhany

That's not opto isolation, its magnetic, right ??

So the OPs request is not feasible.

hamilton

PS: OK, solar cells maybe.

Reply to
hamilton

Yes, just meant as a hint that you can do this stuff at high isolation voltages.

Maybe feasible but it gets expensive.

With small footprint and height that can become a challenge.

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Regards, Joerg

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Reply to
Joerg

Thanks , yes galvonic isolation. I apologize. It seems I cant find anything in smt from Murata. the .25w would be nice. That sip package really blows.

Reply to
Johnny5

TDK's CC-E series is pretty nice, but won't quite get down to 8V on the input (9-18V, IIRC). We've used them in a bunch of places.

Reply to
Spehro Pefhany

There are isolated surface-mount DC/DC blocks around, like in the Digikey catalog. I like the sips because they use available height and save pcb footprint area.

We sometimes use cheap (about $1) IDSN line transformers and 2N7002s to make our own isolated power supplies.

John

Reply to
John Larkin

Motor. Long fiberglass rod. Generator. Megavolts of isolation.

John

Reply to
John Larkin

... minor imbalance, some rumbling is heard, bigger imbalance, snapping noise, stuff flying about, hissing, amperage stench develops, siren begins to wail, the captain from engine company 89 hollers something, his guys hurriedly don their helmets ...

:-)

--
Regards, Joerg

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Reply to
Joerg

Acoustic coupling through capacitor-like ceramic thingy -- used on high kV isolated instrumentation amps?

Opto power is very low transfer efficiency.

Grant.

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Reply to
Grant

Yes, you can possibly use ultrasonic transformers. Unfortunately they have remained boutique parts, probably quite expensive.

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Regards, Joerg

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Reply to
Joerg

You would enjoy that, wouldn't you?

John

Reply to
John Larkin

That's still a lot higher than dimbulb's efficiency.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.
Reply to
Michael A. Terrell

On a sunny day (Thu, 29 Apr 2010 13:27:16 -0700) it happened John Larkin wrote in :

Well, been thinking: Motor, belt, generator. It is not optical, but OK, if the belt is isolating you get a very good efficiency :-)

Reply to
Jan Panteltje

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