A control circuit of a driving circuit for supplying a driving current to a light source includes: a pulse width modulation (PWM) input terminal configured to receive an input dimming pulse having an input duty ratio corresponding to a target light quantity of the light source, the input dimming pulse being pulse-width modulated; and a dimming controller configured to convert a period and a pulse width of the input dimming pulse into digital values, reconvert the digital values into an output dimming pulse having an output duty ratio which is the same as or different from the input duty ratio, and control the driving current to be on and off based on the output dimming pulse.