OPTOISOLATED DC-DC
in [Design]
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From: Johnny5 on 29 Apr 2010 15:27 On Apr 29, 10:42 am, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 > > <dirtylogicdesi...(a)gmail.com> wrote: > >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, > > 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 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.
From: Spehro Pefhany on 29 Apr 2010 15:46 On Thu, 29 Apr 2010 12:27:11 -0700 (PDT), Johnny5 <dirtylogicdesigns(a)gmail.com> wrote: >On Apr 29, 10:42�am, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 >> >> <dirtylogicdesi...(a)gmail.com> wrote: >> >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, >> >> 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 > >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. 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.
From: John Larkin on 29 Apr 2010 16:25 On Thu, 29 Apr 2010 12:27:11 -0700 (PDT), Johnny5 <dirtylogicdesigns(a)gmail.com> wrote: >On Apr 29, 10:42�am, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 >> >> <dirtylogicdesi...(a)gmail.com> wrote: >> >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, >> >> 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 > >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. 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
From: John Larkin on 29 Apr 2010 16:27 On Thu, 29 Apr 2010 11:58:40 -0700, Joerg <invalid(a)invalid.invalid> wrote: >hamilton wrote: >> On 4/29/2010 12:09 PM, Joerg wrote: >>> Spehro Pefhany wrote: >>>> On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 >>>> <dirtylogicdesigns(a)gmail.com> wrote: >>>> >>>>> 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, >>>> >>>> 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. >>> >>> Even that I'd try to power magnetically through some porcelain or glass >>> insulation. >>> >> That's not opto isolation, its magnetic, right ?? >> > >Yes, just meant as a hint that you can do this stuff at high isolation >voltages. > > >> So the OPs request is not feasible. >> > >Maybe feasible but it gets expensive. > >> hamilton >> >> PS: OK, solar cells maybe. > > >With small footprint and height that can become a challenge. Motor. Long fiberglass rod. Generator. Megavolts of isolation. John
From: Joerg on 29 Apr 2010 16:33
John Larkin wrote: > On Thu, 29 Apr 2010 11:58:40 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > >> hamilton wrote: >>> On 4/29/2010 12:09 PM, Joerg wrote: >>>> Spehro Pefhany wrote: >>>>> On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 >>>>> <dirtylogicdesigns(a)gmail.com> wrote: >>>>> >>>>>> 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, >>>>> 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. >>>> Even that I'd try to power magnetically through some porcelain or glass >>>> insulation. >>>> >>> That's not opto isolation, its magnetic, right ?? >>> >> Yes, just meant as a hint that you can do this stuff at high isolation >> voltages. >> >> >>> So the OPs request is not feasible. >>> >> Maybe feasible but it gets expensive. >> >>> hamilton >>> >>> PS: OK, solar cells maybe. >> >> With small footprint and height that can become a challenge. > > > Motor. Long fiberglass rod. Generator. Megavolts of isolation. > .... 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 http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |