I'm fiddling around with a LED controller design - fairly typical. It will use a TI tlc5926 LED driver (nice family) which provides a constant-current sink for each of 16 channels. It can handle up to 120mA per channel, though I'm currently only targeting around 50mA or so. So one provides a power rail to the anodes of all the LEDs, and the cathodes go to each channel pin - pretty simple.
I was originally planning on using ordinary headers and IDC connectors with ribbon cable to connect the LEDs - they're on a remote board. Then I started looking at the actual currents ... 16 channels all on at 50mA is 800mA. If they're pulling the full 120mA per channel that's almost 2A. That little rinky-dink 22ga wire in the ribbon cable as the power rail just won't cut it. Or will it ? I've seen charts that show 22ga good for up to 5A for "short" runs, whatever short means. But an online calculator says I need 13ga wire for 2A at 3.3V over 2 meters.
I suppose I could double up on the power rail pins, use 2 or 3 in parallel. So 19 pins/wires to handle the 16 channels. Except I'm using 4 banks - 4 power rails - and switching between them to get 64 LEDs out there. Now we're just adding pins and adding pins ...
Another method might be to use the IDC/ribbon cable for the 16 channels only, and another connector type with heavier wire for the power rails. That would certainly work, but begins to get a little kludgy. It would be nice to have it all in a single connector.
Can anyone suggest a convenient connector type for this ? Also, what gauge wire would I need ? I've been digging and reading, but I'm a little bleary. Say worst case to supply 2A at 3.3V over 2 meters.