Abstract
A control circuit of a driving circuit for controlling a light emitting diode (LED) light source having a plurality of areas is provided. The control circuit includes the error amplifiers receiving a feed back current signal and a external reference voltage, and generating an error signal; a buffer register receiving a serial digital signal and generating the parallel digital signals; a work register receiving the parallel digital signals and a trigger signal, and outputting the parallel digital signals when the trigger signal is at a relatively high level; and a switch module having the power switches, each of which receives the error signal and the parallel digital signal for generating a driving signal to control a driving current of a specific area of the light source, in order to control the brightness in each area of the LED light source.