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LED-Wiz on 12V circuit

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Green Giant:


--- Quote from: drventure on January 23, 2012, 12:18:36 pm ---Yep, that circuit should do the trick.

Really, you could use an opto-isolator or a solid state relay (SSR), but then, a lot of SSRs actually use opto-isolators internally...

What sucks is that'll be a bit of wiring..

--- End quote ---
Thanks.  I am not to worried about the wiring cause this will be for just 3 RGB signals so 9 little circuits total.

Almost all my signals are for my electric ice buttons, but I think I had a few extra ports that can be utilized for a side project.

yaksplat:

Given the choice, I'd just buy a new LED wiz and sell off the old one, or save it for 5V led's.

MonMotha:

I was of the impression that all LED-Wiz outputs are sink-only and "high voltage" tolerant.  You can hook them up to any voltage you want, subject to a maximum (probably 25V or greater) as long as the ground is referenced to the same ground as the LED-Wiz.  This is a very typical arrangement.  The "bank voltage select" is only for hooking up the on-board freewheeling diodes, which are not necessary for LED loads.

If indeed your LED-Wiz is only 5V compliant (I very much doubt it), you can actually get by with just a transistor rather than needing an optoisolator.  The circuit you posted above probably doesn't do what you want here, anyway.

I'd ask RandyT.  I suspect this is far simpler than you are making it to be.

Green Giant:


--- Quote from: MonMotha on January 25, 2012, 12:07:55 am ---I was of the impression that all LED-Wiz outputs are sink-only and "high voltage" tolerant.  You can hook them up to any voltage you want, subject to a maximum (probably 25V or greater) as long as the ground is referenced to the same ground as the LED-Wiz.  This is a very typical arrangement.  The "bank voltage select" is only for hooking up the on-board freewheeling diodes, which are not necessary for LED loads.

If indeed your LED-Wiz is only 5V compliant (I very much doubt it), you can actually get by with just a transistor rather than needing an optoisolator.  The circuit you posted above probably doesn't do what you want here, anyway.

I'd ask RandyT.  I suspect this is far simpler than you are making it to be.

--- End quote ---
I am only trying to get 3 inputs off the board, maybe 9, to cover 0-12V while the rest will be putting out a 0-5V signal.

Even if my LED-wiz's could handle a 12V signal, I can't send that much juice to my electric ice buttons.

A transistor would only work for on-off, but I really want to run a RGB attract mode with these separate 12V led lights; so I need to handle 0-48 PWM intensity.

Do you have any suggestions for a 0-12V signal from a 0-5V controlling signal?

MonMotha:

As the LED-Wiz is sink only, you should be able to mix voltages within a bank.  The LED-Wiz doesn't actually provide a "5V signal", it just effectively turns on/off a switch to ground to provide or interrupt a path for electricity to flow from whatever voltage supply you select back to ground.  Now, if the rev 1 LED-Wiz hooks the bank common up to 5V internally, you've got a problem unfortunately.  I'd really recommend just trading out for a new one, if that's the case, since all your problems will magically go away, and you can get by without a single external component, then.

Please just ask Randy about this.  The documentation on the website for the old model doesn't answer a very important question for this usage.  It's somewhat likely that you have no problem at all, here.

If you must use what you have, and what you have is really limited to 5V, by far the easiest solution is a solid state relay.  You can get smallish ones that'll do what you want, here.

There are some other options that may be cheaper if you're willing to string a few components together and/or don't need a ton of current handling per channel.  Basically, take the original optoioslated circuit you posted and remove Rout.  In its place, substitute your LED load, including appropriate resistor for 12V.  Rin should be ~220 ohms. Use something like an LTV-815 for the optoisolator.  That'll get you about 80mA per channel with only 2 extra parts per channel.  If you need more than 80mA per channel, another resistor and a suitably sized transistor will get you well more than the LED-Wiz could originally handle, if you want.

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