Design and implementation of dimmable LED control circuit with DALI protocol

In this paper, a digital addressable lighting interface (DALI) protocol is studied and applied to a Light Emitting Diode (LED) lighting system. The DALI protocol was introduced and the dimmable LED drivers were realized. The user interface program in this system was developed by using the Microsoft Visual C#. Also, an USB-DALI conversion bridge circuit was built for communication between the computer and the LED driver. In addition, a micro-controller PIC 16F684 was used for dimming control, processing DALI signal, and coding the protocol program. Finally, a lighting system prototype based on DALI protocol was implemented. The output loads are three LED modules, each module includes 36 red LEDs and 13 blue LEDs. The DALI lighting control can not only use electrical control devices to individually control the dimming, but also can cope with groups of lights, and use broadcast modes to control the lights in group, which can be realized in the laboratory prototype.