Daily Archive for August 24th, 2010

LED Wall Lamp Schematics and PCB Layout

(Note: a hardware failure caused this post, originally posted August 17, to be lost…)

I’ve pretty much finalized the schematics for the wall lamps. They’re available as a PDF or as a gschem file (with a symbol for the TLC5926).

I chose TI’s TLC5926 to drive the LEDs. It is a constant current sink, so it can drive common anode LEDs. It has 16 output channels, each capable of sinking up to 120mA, and the outputs can be placed in parallel.

I decided to order some professionally-printed boards from ExpressPCB. I used their PCB layout tool (which runs fine in Linux under Wine) to create a board that could handle sinking up to a total of about 6A (roughly 2A per channel):

You can grab the PCB layout file here.

The 5926 is controlled by serial input, which should be a good way to get data over long distances. So, I wired up a DB9 connector with all of the relevant data lines that will come from the FPGA.

The boards should be here in a few days; ExpressPCB has really fast turnaround time for their MiniBoard service. I’ll end up with 6 of them, which will probably be useful if (i.e. when) I mess something up.