Patent ID: 8174212

Claim:
A driving arrangement for a plurality of light emitting diodes (LEDs), the driving arrangement comprising: a plurality of serially connected first LEDs coupled to a source voltage; a plurality of first electronically controlled switches, each associated with a particular one of the plurality of serially connected first LEDs and arranged to provide, when closed, a bypass current path for said associated first LED; a control circuitry coupled to a control terminal of each of said plurality of first electronically controlled switches, said control circuitry arranged to close a number of said plurality of first electronically controlled switches, said number responsive to a voltage level of the source voltage; a second LED serially coupled with said plurality of serially connected first LEDs; a second electronically controlled switch arranged to provide, when closed, a bypass current path for said second LED, said control circuitry coupled to a control terminal of the second electronically controlled switch; and a plurality of thermal sensors each associated with one of the plurality of serially connected first LEDs, the output of each of said thermal sensors coupled to said control circuitry, wherein said control circuitry is further arranged to monitor said plurality of thermal sensors, and in the event that the output of any of said thermal sensors are indicative that the temperature of the associated LED has exceeded a predetermined value, said control circuitry is arranged to close said first electronically controlled switch associated with said LED exhibiting said excessive temperature thereby bypassing said LED exhibiting said excessive temperature, and substitute said second LED and said second electronically controlled switch for said LED exhibiting said excessive temperature and said associated first electronically controlled switch.