Completed 1 foot tile

LED Lighting Design

By admin, July 3, 2015

LED lighting panel prototype designed, with printed circuit boards laid out and assembled…

PCB chaining

The PCBs connect in series to create large arrays of LEDs

Two chained boards

Two boards chained together for first testing

I’ve been working on hardware to do “proof of concept” in the arena of LED lighting. I developed and breadboarded circuits to control large arrays of Cree LEDs (single color and RGB) using Texas Instruments driver chips. I then laid out printed circuit boards (PCBs) prototype circuit boards. The PCB design was complicated by the requirement to keep all LEDs in fixed positions, and do no “gate swapping” to make trace routing and pin assignments easier.

Custom PCBs

Four layer PCBs for LED lighting project

I ordered boards from Advanced Circuits, who provide pretty good online tools to review designs for problems before ordering. I also like that Advanced builds all their boards in the USA. While they are not the cheapest source, they are easy to work with, can build almost any conceivable PC board you would ever need, and seem to provide quality product.

Hot air rework station

Building boards with 0.5mm fine pitch parts using hot air rework

We now have our first round of PCBs, which I built myself on my Aoyue SMT hot-air rework station. Fine pitch SMT is always a pain, but this station makes it reasonable to build small batches of boards without a bunch of setup and tooling costs. I have learned that Kapton solder stencils work ok for building simple boards, but a stainless steel stencil is a wise investment for fine lead spacing.

Completed 1 foot tile

Completed 1 foot square LED lighting tile

Processor and Supply

Processor and Power Supply

A completed 12 x 12 inch prototype “tile” is now in the customer’s hands while we evaluate next steps in the evolution of this product. The light output is impressive, and unfortunately quite difficult to photograph!