A controller for controlling dimming of a light source includes a detector, a dimming signal generator coupled to the detector, and a pulse generator coupled to the dimming signal generator. The detector can detect a startup phase of a burst dimming cycle of the light source and can generate a triggering signal when the startup phase ends. The burst dimming cycle includes an ON period and an OFF period. The dimming signal generator can trigger the ON period of the burst dimming cycle for a predetermined duration in response to the triggering signal. The pulse generator operable for generating a pulse signal to control a current through the light source can be enabled during the ON period and disabled during the OFF period.