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Electronics => Beginners => Topic started by: sk614 on July 26, 2016, 06:41:28 am

Title: Adding regulated outputs
Post by: sk614 on July 26, 2016, 06:41:28 am
I have two voltage regulator that convert to 3.3V.  Is it even possible to add them together to get higher voltage?
Title: Re: Adding regulated outputs
Post by: Simon on July 26, 2016, 06:42:29 am
if they share the same ground, NO.
Title: Re: Adding regulated outputs
Post by: Zero999 on July 26, 2016, 07:03:46 am
It depends on the regulator: Part number? Datasheet?
Title: Re: Adding regulated outputs
Post by: MosherIV on July 26, 2016, 07:15:00 am
Quote
I have two voltage regulator that convert to 3.3V.  Is it even possible to add them together to get higher voltage? 
Simple answer NO.

You can do it with 1 voltage regulator:
http://www.pcsilencioso.com/cpemma/diodes.html (http://www.pcsilencioso.com/cpemma/diodes.html)
Look at the 'fixed regulator' section and how it is possible to raise the ground pin.
It is also possible to do it with diodes and zener diodes.
Title: Re: Adding regulated outputs
Post by: Zero999 on July 26, 2016, 07:53:55 am
Quote
I have two voltage regulator that convert to 3.3V.  Is it even possible to add them together to get higher voltage? 
Simple answer NO.

You can do it with 1 voltage regulator:
http://www.pcsilencioso.com/cpemma/diodes.html (http://www.pcsilencioso.com/cpemma/diodes.html)
Look at the 'fixed regulator' section and how it is possible to raise the ground pin.
It is also possible to do it with diodes and zener diodes.
Yes. It can be done, so long as the load on the regulator use to lift ground pin is equal to or greater than the current taken by the other regulator.
Title: Re: Adding regulated outputs
Post by: sk614 on July 27, 2016, 06:56:23 am
This is what I am using, a RF to DC convertor.  http://www.powercastco.com/test566alpha/wp-content/uploads/2009/03/p2110b-datasheet-v12.pdf (http://www.powercastco.com/test566alpha/wp-content/uploads/2009/03/p2110b-datasheet-v12.pdf)

For reason not possible, why is that?
Title: Re: Adding regulated outputs
Post by: Simon on July 27, 2016, 07:01:50 am
your input and output needs to be isolated otherwise when you put them in series you will connect the ground of one to the positive of the other that has the same ground, thus short circuiting one of the outputs. If they are fed from isolated inputs you can put them in series or if they use a transformer making the inputs isolated from the outputs.
Title: Re: Adding regulated outputs
Post by: suicidaleggroll on July 27, 2016, 07:06:02 am
That device doesn't give you a continuous 3.3v.  It uses the accumulated RF energy to charge a capacitor, then when it hits a set voltage it boosts it up to the voltage you want until the cap decays back down, and then it shuts off the output.  Since the output is intermittent, you can't stack two of them and expect to get 6.6v.  Most of the time you'd get 0, sometimes you'd get 3.3 from one device or the other, and very rarely (I'm assuming, I don't know your load or what kind of duty cycle you'd get from this device) you might get 6.6v.

The two devices obviously couldn't share a ground, you'd need to stack one of their grounds on top of the other's Vout, and then take care of the myrid of problems associated with doing so (your two RF antennas wouldn't share a ground, your digital signals wouldn't share a ground, etc).