So here we have it the first LED design on my website.
Not my first actual design by any means but one I just installed and hence have fresh pictures of!
These were built as a friends birthday present/housewarming gift and were originally intended to be separate and wall hanging. As can seen above though, that didn't quite pan out. The lighting in the friends initial apartment was abysmal and needed an overhaul whereas the lighting in the second place was already pretty good. Also whereas in the first apartment the lights were to provide the majority of the illumination, in the second, they only really needed to provide some accent lighting.
The LEDs chosen were CREEs XH-G LEDs and are a reasonably powerful lighting class LED. As is typical of CREEs LEDs they come in a variety of specifications which helps makes the appropriate design of domestic lights a breeze. For a long time I have been unimpressed with the overall quality of light that CFLs and low CRI LEDs provide. As a result I take advantage of the higher CRI binned parts whenever I can. Of course this comes at an efficiency penalty but it's well worth it for the quality of light and atmosphere the right lighting can create in a room.
Each XH-G is a 1 watt device and I used the 90 CRI part with a warm white CCT of 2700K. Given the LEDs relatively high efficacy the 15 LEDs used in this design have the potential to put out a significant amount of light. When driven hard each lamp can put out in excess of 1000 lumens. This is a decent amount brighter than your typical 60 watt incandescent bulb, with both lamps putting out significantly more light than a single 100 watt.
The original power supply was going to be a laptop brick, split between the two lamps, so I had to come up with some sort of solution for driving the LEDs. As I was already familiar with the ZXLD1371 from Diodes Inc. this was the route I decided to go.