Patent ID: 7781979
Filing Date: 2010-08-24
Classification: H05B

Abstract:
1. An apparatus, comprising: at least two LEDs connected in series between a first node and a second node, wherein a series current flows between the first node and the second node when an operating voltage is applied across the first node and the second node; at least one controllable current path connected in parallel with at least a first LED of the at least two LEDs for at least partially diverting the series current around the first LED; and at least one controller for monitoring at least one parameter representative of the operating voltage and determining a maximum number of LEDs of the at least two LEDs that can be energized by the operating voltage, the at least one controller controlling the at least one controllable current path so as to increase an amount of the series current that is diverted around at least the first LED when the maximum number is less than a total number of all of the at least two LEDs connected in series.