Abstract: An LED dimming method, a dimming controller and system are disclosed. In a phase where a duty cycle of a PWM signal does not exceed a first threshold, every n periods of the PWM signal is taken as one set, taking a set as an output unit, and the duty cycle of the PWM signal is changed by incrementing or decrementing a average duty cycle by a first predetermined amount ?P1 (0<?P1<0.2%), thereby adjusting an output current of an LED. In this way, the duty cycle of the PWM signal can be configured to increment by the first predetermined amount ?P1 that is smaller than 0.2%. Moreover, when the first threshold is 10%, it can be ensured that each period of the PWM signal with duty cycle value within the range of 0-10% can be identified.

Abstract: An LED dimming method, a dimming controller and system are disclosed. In a phase where a duty cycle of a PWM signal does not exceed a first threshold, every n periods of the PWM signal is taken as one set, taking a set as an output unit, and the duty cycle of the PWM signal is changed by incrementing or decrementing a average duty cycle by a first predetermined amount ?P1 (0<?P1<0.2%), thereby adjusting an output current of an LED. In this way, the duty cycle of the PWM signal can be configured to increment by the first predetermined amount ?P1 that is smaller than 0.2%. Moreover, when the first threshold is 10%, it can be ensured that each period of the PWM signal with duty cycle value within the range of 0-10% can be identified.