Patent ID: 8531115

Claim:
A method for controlling a string of multiple light sources operatively connected in series and powered by a driver circuit having an unloaded power source voltage by providing an alternative current path around each of one or more substrings having one or more of the multiple light sources, each substring having an operating voltage comprising: (a) allowing significantly less than operating current through the alternative current path until an open circuit condition in the substring indicative of a failure of a lighting source of the substring; and (b) triggering substantially all operating current to pass through the alternative current path of the substring by a triggering voltage which is effective over a range of ambient temperatures and operating conditions by the unloaded power source voltage of the driver circuit being greater than the operating voltage of the substring and the trigger voltage needed over the temperature range; (c) to allow operating current to automatically bypass the substring of light sources including the light source or sources sensed to have failed so it is available for other light sources in the string over the range of ambient temperatures and operating conditions.