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Unread 02-22-2015, 11:12 PM
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Re: LED Strip Power

Would throwing a couple of 5v regulators in parallel work for your application? Something like 4 LM323's on a perf board (with appropriate filtering) should be enough for your application.

Edit: See below and apparently don't do this. Also I may have a soon-to-be-crispy board floating around and should actually learn to EE.
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Last edited by wmarshall11 : 02-23-2015 at 10:16 AM.
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Unread 02-23-2015, 12:25 AM
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Re: LED Strip Power

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Originally Posted by wmarshall11 View Post
Would throwing a couple of 5v regulators in parallel work for your application?
AAAAAAAAAAAAA!

Putting regulators in parallel is never a good idea unless you put enough resistance between each of the outputs to allow the variation in output voltage to go somewhere other than frying electronics.
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Unread 02-23-2015, 08:00 AM
Mike Bortfeldt Mike Bortfeldt is offline
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Re: LED Strip Power

I've used this successfully in the past.
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Unread 02-23-2015, 01:06 PM
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Re: LED Strip Power

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Originally Posted by Mike Bortfeldt View Post
I've used this successfully in the past.
Use this or one of the 12V to 5V Voltage Converters from previous years (check the output current capacity first).


Quote:
Originally Posted by wmarshall11 View Post
Would throwing a couple of 5v regulators in parallel work for your application? Something like 4 LM323's on a perf board (with appropriate filtering) should be enough for your application.

Edit: See below and apparently don't do this. Also I may have a soon-to-be-crispy board floating around and should actually learn to EE.
A single LM323 would be sufficient if you have a large enough heat sink. Putting multiple linear regulators in parallel will not give you more output current capacity than with just one. Increasing the output current capability of a linear voltage regulator is done by adding a large output device.


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Originally Posted by GeeTwo View Post
AAAAAAAAAAAAA!

Putting regulators in parallel is never a good idea unless you put enough resistance between each of the outputs to allow the variation in output voltage to go somewhere other than frying electronics.
The internal circuitry of all the linear regulators I have ever looked at are such that they can only source current and cannot sink current. Because of this, they cannot "fight" each other. The one that has the highest output voltage, by even a few millivolts, will end up supplying most or all of the output current. The other ones will sense the higher output voltage and shut off their output stage so that they supply little or no current to the load. In this mode of operation, they are not likely to be damaged.

The output isolating resistors will cause the output voltage to be lower than what you may want unless there is circuitry to compensate for them.
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Unread 02-23-2015, 02:32 PM
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Re: LED Strip Power

I second the 9A Pololu converter. This is a newer model than what we used last year, and handles over-voltage better. Make sure you add a decently beefy capacitor on the output. For the further paranoid, you can add a reverse biased zener diode to short power and ground when you go over voltage.

Quote:
Originally Posted by philso View Post
Use this or one of the 12V to 5V Voltage Converters from previous years (check the output current capacity first).
Nothing in previous KoP's goes over 3 amps I believe.



Quote:
Originally Posted by philso View Post
The internal circuitry of all the linear regulators I have ever looked at are such that they can only source current and cannot sink current. Because of this, they cannot "fight" each other. The one that has the highest output voltage, by even a few millivolts, will end up supplying most or all of the output current. The other ones will sense the higher output voltage and shut off their output stage so that they supply little or no current to the load. In this mode of operation, they are not likely to be damaged.

The output isolating resistors will cause the output voltage to be lower than what you may want unless there is circuitry to compensate for them.
Correct, you get pretty vicious leader/follower cycles. There are some switching power supplies that do support paired regulators, but they're not very common or cheap.

What you can do is independently power a subset of the strips. Last year we had 10 meters of WS2812 broken up into 5 strips, and used 3 separate regulators. You can see the cable bundle here: http://hackcasual.io/images/bling_installed.jpg
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