A lighting device comprising a lighting unit comprising a plurality of lighting modules and a termination module, wherein the termination module is configured to have an electrical characteristic different from that of each lighting module, such that it draws a different amount of current in response to an applied drive voltage. The present invention suggests automatically determining a lighting module count of the lighting unit upon detection of the termination module, by measuring a change of a current passing through the lighting unit while sequentially activating the modules of the lighting unit.