Using the Right Power Supply Setup

Hi there,

I’m finishing up the design for a project of mine, and I want to see if my final idea is feasible - if I want to power two 12V, 1.3A/phase steppers with two DRV8825 Drivers, and I want to also power a 12V ‘P’ model Firgelli (using the Linear Actuator Control Board: http://www.firgelli.com/Uploads/LAC_Datasheet.pdf):

  1. How can I connect a single power supply to the three different drivers?

  2. is it okay if I supply a single 12V 6A power supply to all three of these boards - the two DRV8825s and the LAC board?

  3. Also, will supplying the 6A to the different drivers damage them in any way?

The reason I have these questions is because all three of these drivers support 12V of voltage supply, but I don’t know how much current I’m allowed to supply to the drivers.

I really would like to limit my project to using only one power supply. I’ve included a drawn diagram of my setup below. Thanks so much in advance.

You must connect the Arduino GND to the ground of the motor drivers !

The Arduino board is powered with usb, but you can also power that with your power supply. The 6A is not a problem, as long as it is 12V it is okay. Even 12V with 6000A is not a problem. You have to take care about your wiring, when you make a shortcut, the 6A can do a lot of damage.

So what’s a good connector or solution to power all 4 devices if my power supply has only one or two outputs?

Thanks for your input, it’s greatly appreciated!

Looks okay, just make sure Arduino Gnd goes to motor Gnd as noted. Make yourself a 4-way splitter cable, all originating at the 12V supply. Arduino will run from 12V supply if it's connected, and switch to USB when it's not.

Thank you all for your advice! It helped immensely

Hey all,

I just wanted to confirm my final design. I have a separate logic/motor power supply setup, but could easily use one more split connection from my external power supply to connect to the VIN and GND pin on the Arduino to remove USB supply.

I have my drivers and LAC hooked up to a 12V 10A power supply, with the ‘+’ and ‘-’ going to each, and then the ‘-’ from each driver also going to the GND on the Arduino as you all suggested.

I had to do this project for a work assignment, which is why I couldn’t start with a smaller setup. Below is a picture of my final diagram, and if this has any errors if you would let me know that would be phenomenal! Thanks guys

Looks ok.

Awesome, thanks CrossRoads

Also, would it be a good idea to use some kind of fuse between the wall outlet and the power supply such as:

And if so, what fuse should I be using?

Thanks again!

Also, would it be a good idea to use some kind of fuse between the wall outlet and the power supply

What are you trying to protect? In electronics a fuse is useless because it takes too long to blow, by which time the electronics is dead anyway.

I really just liked the one piece switch mechanism on this particular part, but it appears to require a fuse to function. The power supply has it's own protection. Are there any switches you would recommend that have a removable ac power cord?

No not particularly it depends on what you like. You can get that connector without the fuse but if you just ignore the fuse it does no harm, not much good though in my oppinion.