App note: High power LED driver with PIC12F675

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.

Join the Conversation

1 Comment

  1. I made turn signal lamps for my brother’s motorbike using circuit presented in this application note. I used 3W white LEDs as a light source, LM339 comparator and a PMOS transistor from Vishay. I must say it works pretty fine and it has never failed. The ripple current is very close to the calculeted one using equations given there. If you are looking for a cheap and reliable (to some point) circuit – just use it.

Leave a comment

Your email address will not be published. Required fields are marked *

Notify me of followup comments via e-mail. You can also subscribe without commenting.