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ATX power distribution board.

Posted by TbirdMan 
ATX power distribution board.
March 27, 2016 12:46AM
I am working on designing an ATX PSU power distribution board with the current features:

20 or 24 pin ATX plug in mainly for control
5V USB output coming from the 5Vsb (possibly a jumper to choose 5Vsb or main 5Vline?) to power electronics
2 pin terminal for PS_ON (can be jumpered or have a switch added to manually control)
LED + terminal for PWR_OK
provision for a 10W10Ohm resistor to stabilize 5V power (some supplies require this, mine doesn't seem to like it.)
2 voltage rails, fed from PCIe power plugs or screw terminals each with a blade fuse provision targeting a 15A rating on each rail.

I am looking for input for other features people might want to see, any ideas?
Re: ATX power distribution board.
March 27, 2016 01:41AM
you mean a bit like this

Re: ATX power distribution board.
March 27, 2016 01:57AM
closer to this Dangerous Prototypes ATX breakout board.
but engineered to power a 3d printer. those breakout boards can't provide the current (ATX 24 pin only has 2 12V lines running through 18ga wire) and don't breakout 5Vsb, or the PS_ON for control by the arduino etc.
Mine will have provisions for the PCIe rails to plug in or screw terminals if you want a different power source. I am still in the early planning phase of this, gathering ideas and researching components/design.
Re: ATX power distribution board.
March 29, 2016 05:45AM
Considering there are at least two this sort of thing already readily available for quite cheap, I suspect your wasting your time...also trying to compete with china is doomed to failure. But hey its your time to waste if you wish.
Re: ATX power distribution board.
March 29, 2016 12:31PM
Neither of these breakout boards is capable of powering a printer, they are for low current bench testing. They really aren't anything like what I want to build. they typically have fuses around 1-2A. they also only breakout the ATX motherboard connector which only has 2 18ga 12V wires from a single rail. My design will have the PCIe plugs providing two ~15A +12v rails (assuming the PSU is capable of providing at least that) with replaceable fuses, will breakout the 5V standby line to run the electronics with the main PSU turned off, and the PS_ON line to allow the electronics to turn the PSU on/off at will. And I would only be designing this and put it out as an open source design, so I wouldn't mind the Chinese making them.
Re: ATX power distribution board.
April 01, 2016 07:33AM
One wonders a bit what the purpose of such a board could be. For just getting juice out of an ATX supply a bent paperclip is entirely sufficient.

Generation 7 Electronics Teacup Firmware RepRap DIY
Re: ATX power distribution board.
April 01, 2016 09:36PM
An atx psu, even at low load, will waste power. Being able to turn the main psu off but leave the electronics running off the 5Vsb and have the controller turn the psu on and off will save energy and make it more stand alone. And using the standard plugs will make using an atx psu more plug and play. Also, using a bent paperclip is lazy and prone to bad connection and getting shorted out. Also, some power supplies require a load on the 5V line to properly regulate voltages.
Re: ATX power distribution board.
April 16, 2016 12:40AM
I have a design I am happy with so far, but would like some input from others. How do I go about posting the design, do I upload it in Gerber or will the diptrace file work?
Re: ATX power distribution board.
April 16, 2016 11:09AM
I figured out how to turn them into .png files, these are the top and bottom. based on some input i got elsewhere I think I am gonna make the board a bit wider and make the 12Vin traces a bit wider.
open | download - ATX_Power_Board_Top.png (41.6 KB)
open | download - ATX_Power_Board_Bottom.png (29 KB)
Re: ATX power distribution board.
May 05, 2016 02:29AM
Output connectors should be rated at least 20A and all traces should be the same..... the ground plane looping around the atx24 looking a little thin on the edge of the board unless or using 2oz copper

you may as well connect in the 12V rails from the ATX24 connector.

I've designed a couple of these over the years but find that by the time you buy the required connectors in one off quantities you can nearly just straight out buy a meanwell (clone) 350W SMPS.
Re: ATX power distribution board.
August 10, 2016 07:44PM
The ground plane around the edge should not be carrying any significant current. the main power ground will be the connections between the PCIe input grounds and the V1/V2 grounds, the other grounds will be for electronics (Raspi 3 + 7in touchscreen+RAMPS). I rated the connectors at 16A since the RAMPS board is not rated higher then that anyway and if I need more there is the option of an SSR. I avoided Connecting the ATX24 12V connectors because i wanted to keep the V1 and V2 +V lines independent of each other in case I or anyone wanting to use my design wanted to run 24V on one from a secondary PSU. My goal was flexibility. I have put in an order for 5 of these boards and the parts for one. Yes, it was pricy all together (around $80) but I view it as an educational expense as a student. I don't think it would be right to graduate with a Masters in Systems & Laboratory Automation without ever having designed and built a PCB of my own.

EDIT: I also left the solder mask off the main power traces to allow for adding solder to beef up current capacity if it is too weak.

Edited 1 time(s). Last edit at 08/10/2016 07:46PM by TbirdMan.
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