I’ve just soldered up the prototype of a busboard I’ve been working on for a little while and am rather happy to say it works rather nicely indeed.
It uses a couple of DC-DC converters to provide a bipolar 12v supply from a 15.5 to 18.5v DC brick. There’s no 5v rail as…I don’t have any 5v modules, basically. Modern modules now use on-board 5v regulators, so I relegated it to the rubbish bin.
I designed it with 3 primary considerations:
- That it be relatively inexpensive,
- That it be as low-profile as possible for maximum skiffage, and
- That it be relatively high-performance in terms of noise, ripple etc.
1 and 2 were easy to achieve - the parts cost is about 50 dollars excluding the headers/power brick.
The height of the board at its maximum is 12mm. It would be 10mm if I hadn’t used insulated spade connectors. You could always directly solder wires to the holes for the faston terminals if you really wanted to get it as low as possible, I suppose, but I like tab terminals. It’s designed to be mounted with the components on the underside, although either orientation is fine.
3 on my list is ongoing as I haven’t had a chance to measure the ripple using my oscilloscope apart from a rudimentary check of the +ve rail which came to about 10mVp-p. I need to fully stress test the board at max current draw though before I can be sure of the performance. According to my calculations and the datasheets for the converters, it should be pretty good as I used their recommended pi filter on the output. I also added EMI filtering so it shouldn’t cause any radiated EMI.
Anyway, it’s still in its prototyping stage, but I thought I’d announce it to see what people think. Once it’s finalised, I’ll probably make the PCBs available.