Torches (flashlights) are quite cool, and spectacularly bright torches are even cooler. However, most DIY torches over a few thousand lumens are cumbersome and impractical, and often have an unusably short battery life. For this project I sought to fix all those issues and more -- a lofty goal of which I ultimately fell somewhat short.
The bulk of the work went into designing the PCB above. It is a boost converter aimed specifically at high power LEDs, and for its design I had the following requirements:
1. Wide input and output voltage range
2. Input current up to 12 amps
3. Output current up to 3 amps
4. Low profile construction, diameter of 1.75" (44mm)
5. Overtemperature and undervoltage cutoff
These goals were met, though with some qualifications. Its input voltage range is 5-40V, and the maximum output is 80V. The physical constraints were also satisified.