Small, USB powered LED lamp with up to 6 1W power LEDs. It uses diodes without a radiator, soldered directly onto the PCB. The power is delivered by the AP63203 step-down converter with up to 2A output current. The LEDs have forward voltage of about 3.1-3.2V at currents around 200mA, that is why I decided to use a simple and cheap 3.3V converter with 1Ohm resistors splitting the power to every LED connected in parallel. This way I could also not solder in all of the LEDs, in the end I went with only 3 of them, as I thought it was enough for my usage.
Schematic
The schematic and PCB were both designed using Altium Designer. Plase don’t mind the LED pin 3 to GND conenction. It turned out that my LEDs actually don’t have the center pin connected to anything, that is why I could do that to better manage the heat. It might be different for your LEDs though, so please check that.
PCB design
The PCB is a single layer design, because I wanted to make it at home. I used an FR-4 board and etched it using B327 after doing the thermal transfer.
3d CASE
The 3d model for the case was designed with Autodesk Fusion 360. It consists of the bottom case and top cover with empty space for a plexi panel. They are fastened together using M3 screws.
Author
Krzysztof Sikora
Cracow, 04.2023