This is a compact single-sided circuit based on a small 8-bit microcontroller (PIC16F18313) that controls a LED2001, a buck LED controller with current feedback. It enables powering a high-power LED with up to 10W.
First prototype
Firstly, I created a functional prototype by producing the PCB in my laboratory using the “press ‘n’ peel” technology.
This initial prototype also includes a rotary encoder for adjusting brightness.
The quadrature signal from the rotary encoder is interpreted by the CPU, which translates this command into a variation of the PWM signal output to the LED2001. The LED is controlled by the buck in current mode.
PCB design
After finalizing the design, I proceeded to order the PCB. In this new version I replaced the rotary encoder with a button to reduce the footprint. The brightness adjustment is now controlled by short and long presses, entirely managed and interpreted by the firmware.
Here is an example of a test for the status LED, which is used to indicate low battery or temperature warning.
Finally the circuit is mounted on the mechanical structure of the flashlight, designed to manage the heat dissipation of both the LED and the buck converter.
ing DIY 
