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Author Topic: Doubling pwm output voltage.  (Read 5818 times)
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I understand the pwm output on the arduinos is 0-5V. Is there a way i could make this voltage go from 0-10V?

Would a king of voltage doubler circuit work on the end of the output. Similar to a voltage divider, but a multiplier instead???

VR
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U of A, Tucson, AZ
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See if this playground article is what you're after:

http://www.arduino.cc/playground/Main/RegulatedPositiveVoltageBooster
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I was looking at keeping things something simple. So would something like this work:

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this voltage doubler would work for something that is on or off for long periods of time, cause it takes some time for the caps to charge. Therefore you will never get a full resolution pwm to work with this circuit.

You are better off working with active components like transistors or op amps? but you need a source of 10+V. Do you have that source available?
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Getting the +10v source is not a problem. Just figuring out a way to control the pwm linearly is the problem!
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You need a transistor driver like the following:



This will give you up to 500mA at 10VDC (minus about .7v drop of the transistor)
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koyaanisqatsi:

i cant see any diagram and it asks me for a password everytime i open up the page.

VR
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Ugg!  Sorry, I do that all the time.  :smiley  Fixed now.
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im trying to dim a flourescent light driver that has pwm and 0v pin, so how would i attach it to that circuit???

Is there a way to have just the doubled voltage outputted?

ie:



I know that circuit you showed would work for a fan etc, but how would i connect the ballast?
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In that case, the load resistor in my diagram becomes a pull-up resistor and the connection to your ballast input comes off of the circuit between the pull-up resistor and transistor.

This will invert the PWM signal, so you'll have to account for that in software.  When the PWM signal is high, the transistor will conduct to ground and put a low on the ballast input.  When the PWM is low, the transistor will be off and the pull-up resistor will put a high on the ballast input.

The values of the resistors can be higher in this case too.  You could probably use 10k resistors for both, depending on how the ballast reacts.  You may need to test with different values to find the best setup.

EDIT: I modified and reuploaded the diagram, which I realized is not the best thing to do right after doing it.  I should have put up a new image instead.  Oh well...   smiley-razz
« Last Edit: April 21, 2009, 10:19:57 pm by koyaanisqatsi » Logged

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You mean like this:



Then arduino pwm 0 - 259 will dim from on to off ( 100% - 0% brightness) and vice versa, if im reading you correct?????
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Yep, that's it.  I am a slightly concerned about tying the Arduino ground to the ballast 0V input.  Be sure that's an OK thing to do before doing it.  It should be explained in the ballast documentation.
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This is the kind of thing im looking at:

http://www.1000bulbs.com/images/PDF/Mark7-0-10V-brochure.pdf

Just scroll down a little to the diagrams and let me know what you think.

VR
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Man, there just isn't very much information on what the "Mark 7 0-10v" signal should look like.  A few docs I found through Google all said something like "supports 0-10v dimming" but none of them spec'd the actual signal.

So I'm not sure what you're going to get when you hit it with a PWM signal.
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Yeah i know what you mean. I know you can hit it with a POT. looks like more research is involved, but at least now i now how to get the pwm signal to it.

Thanks for all your help.

VR
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