A current controlled buck converter for driving high-power LEDs. The PIC12F675 microcontroller has an integrated comparator, which in combination with a low pass filter provides a control circuit for the SMPS.
The circuit is based on a buck topology switching power supply using the on-chip comparator peripheral within the PIC12F675 microcontroller. The switching power supply design ensures efficient power transfer between the system battery and the output LED. Using the attached Flash microcontroller as a control for the driver circuit expands the capability of the circuit to include intensity control, automated intensity compensation for low battery conditions, and the ability to playback preprogrammed Flash sequences. The Flash microcontroller also allows the creation of a custom PC-based graphical user interface, using the PICkit Flash Starter Kit for programming the preprogrammed Flash sequences. The combination of the switching power supply design and the microcontroller results in an efficient circuit with advanced automated features while keeping the circuit simple and inexpensive.