Abstract: A dimming controller can operate in a first mode or a second mode to control dimming of a light source. A voltage control terminal provides a driving signal to control a control switch. When the dimming controller operates in the first mode, the driving signal controls the control switch in a first state and a second state alternately to adjust a first current flowing through the first light element to a target level. When the dimming controller operates in the second mode, the driving signal controls the control switch in the second state to cut off the first current. A high voltage terminal conducts a current flowing through the control circuit and the second light element when the dimming controller operates in the second mode. The control circuit conducts a second current flowing through the second light element during the second mode.