Author Options:

How to step down a 12v DMX LED Controller to 5v? Answered

Hey i currently have an "Abstract MFD-10" DMX controller that i want to run 64 LEDs/2meters of "LPD8806 +5v Strips" off of.

DMX Controller= http://www.abstractavr.com/products/dmx-led-drivers/60w-dmx-led-driver/
Led Strips= http://www.adafruit.com/products/306

How do i step down the 12v supply to 5v while maintaining the flow to keep the strips running effectively?
If you give me the formula for it i can work it out myself and will post here with what i worked out as i enjoy doing my own workings but i am a bit lost with this.

Also I am willing to simply change a component in the controller itself if this would be easier and cleaner (No external boards/components)

Need anymore info just ask.


You'll need a voltage regulator to step the 12V down to 5V. An LM7805 should do the trick.

7805 has a declared max output current of 1A in the datasheet. 2m of that LED strip draws close to 10A @ 5V. So simply put, the 7805 in this case will work as not-so-effective smoke machine.

Think I found a work around


And just working it out but i realised that on the website the strips take 120mA per 1/4 meter isnt 120mA X 8 = 0.98A? so a 7805 should be able to handle it as long as its got a heatsink etc?

According to the site:
Maximum 5V @ 120mA draw per 2.5" strip segment (all LEDs on full brightness)

Now that I recalculated that it seems like both of us were not very good with out numbers :)
2.5" = 6.3 cm therefore (200cm/6.3cm) * 0.12A = 3.8A

As for a working alternative - I have no real suggestion for you as I'm too inexperienced in electronics to think of something suitable, but it seems like you might be onto something with that pc power supply.

This is what I thought. So what could i do to increase the Current?
Im currently desoldering an old DELL (d275p-00) PC powersupply that has a 5v output at 18A
so is it possible to force a higher current (4A) with a low voltage (5v) using
multiple Voltage regulators arranged on a circuit and if so what would the layout of components be?

I recently used a LM1084 in my Infinity Table. It is an adjustable output, 5A voltage regulator. You wire it up just like a standard 1 Amp, LM317. Look it up in LM317 in google and use the same schematics and even the same voltage calculations! Be shure to use a massive heatsink though.

I would love to see this when you are done ! you need any help feel free to PM me

Good Luck!