Patent ID: 8686654

Claim:
A dimmable light emitting diode (LED) illumination system, comprising: a LED driver coupled to receive a DC power supply and a dimming control, the LED driver operates at a plurality of brightness modes and generates a drive voltage and a current control according to the dimming control, the LED driver operates in an active duration mode and an inactive duration mode; a current sink coupled to receive the current control, the current sink controls an LED current through an LED to a substantially direct current during an active duration and an inactive duration; an output capacitor, coupled to receive the drive voltage, the output capacitor provides a supplemental current to the LED during the inactive duration; and wherein when the LED driver alternates between the active duration mode and the inactive duration mode, the LED driver is operating in a first mode that is associated with moderate brightness modes within plurality of brightness modes, and wherein when the LED driver operates only in the active mode, the LED drive is operating in a second mode that is associated with high brightness modes within the plurality of brightness modes, wherein in the first mode, the LED current is smaller than a maximum driver efficiency LED current, and wherein in the second mode, the LED current is larger than the maximum driver efficiency LED current.