A current driver connected with light emitting diode (LED) bars of the maximum number N of channels and driving LED bars of M channels to be driven, includes: PWM input terminal configured to receive PWM-modulated external dimming pulse having duty cycle with a target light quantity common to the LED bars of the M channels; pulse measurement circuit configured to measure period and pulse width of the external dimming pulse and generate digital period data and pulse width data; interface circuit connected to external processor and configured to receive enable data and phase difference setting data; M current sources of the M channels to be driven and respectively connected with corresponding LED bars, and configured to be On-and-Off-switched in response to internal dimming pulse; and pulse generator configured to generate M internal dimming pulses and distribute the M internal dimming pulses to the M current sources.