Theoretical considerations for the design of self-diagnostic circuit for LED based street lightings

Nowadays street lights employing Solid State Lightning devices are increasingly gaining ground. This paper deals with measurement methods of self-diagnostic electronic circuits for street lamps. Diagnostics is based on thermal transient measurement of LEDs. The measurement is achieved via the change in the forward voltage of the p-n junction. This paper shows and compares three different measurement schemes. One of the schemes is demonstrated with a concrete circuit realization. Shunted LED method was selected for demonstration.