ATX Breakout Board design overview

From DP

Power supplies are a constant need around our workshop. With the high volume production of computer PSUx, you can get one really cheap. Our board simply routes all the power lines, to 4mm banana jacks for simpler access. [Available for $xx.xx] at Seeed Studio. Read about the design below.

Contents 1 Overview 2 Hardware 2.1 Power line 4mm banana jacks 2.2 Power switch 2.3 Resettable fuses 2.4 LEDs 3 PCB 3.1 Partslist 4 Taking it further 5 Get one!

Overview

Other then only having easier access to the power lines, our board also has these features, for better ease of use. Resettable fuses on all the power lines Indicator LEDs on all the power lines Indicator LED on the MAINS ON line Indicator LED on the POWER GOOD line Button which pulls the 'green' wire low, telling the PSU to turn on or off, as a motherboard does 10W load resistor on the 5v line, for PSU stability

Hardware

Click for a full size schematic image. Schematic and PCB were designed with the freeware version of Cadsoft Eagle, download the latest project files from our Google Code project page.

Power line 4mm banana jacks

We broke out the 12v, 5v, 3.3v, -5, -12v power lines, as well as 2 ground lines to 4mm banana jacks. The 4mm banana plugs are the industry standard, making the cables interchangeable with any lab PSU.

Power switch

The 'green' wire from the ATX jack is routed to a switch (ON/OFF) which can pull it low. This is the way motherboards control PSU's inside computers.

Resettable fuses

All the power lines are routed through resettable 500mA fuses (F1-F5)

LEDs

Indicator LEDs are connected to the power lines making it easy to spot which fuse blew, in case of a short. We added an LED to the POWER GOOD line, it is used by the PSU to lets the motherboard that the power is safe to use. Another LED was added to the MAINS ON line which lets you know that the PSU is plugged into mains.

PCB

We used the freeware version of Cadsoft Eagle to make the schematic and PCB. Download the latest designs and firmware from the project Google Code page.

• PCB and placement notes
• soldering advise

Partslist

Click for a full size placement image.

partlist

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Taking it further

Here's some ideas for the future:

• List

We'll post the most recent firmware updates on our blog. You can also join the discussion in the [forum].

Get one!

You can [get one for $00], including worldwide shipping.

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