System for starting a high intensity discharge lamp

Abstract

A ballast circuit arrangement with hot restrike capabilities includes an input transformer having a primary winding receptive of line power and a secondary winding over which an output voltage is made available. A first capacitor coupled across the secondary winding of the input transformer develops a voltage charge thereon. A resistor and a second capacitor are series connected to one another and are parallel coupled across the first capacitor. A starting aid device is coupled to the secondary winding of the input transformer and produces an output voltage of a predetermined magnitude. The output voltage of the starting aid is coupled to a spark gap device having first, second and third electrodes associated therewith. A first spark gap formed between the second and third electrode is first fired by the output voltage of the starting aid which in turn triggers the firing of a second spark gap formed between the first and second electrodes. A pulse transformer having a primary winding coupled between the spark gap device and the series connection between the resistor and second capacitor provides a discharge path for the second capacitor. Upon the firing of the second spark gap, the primary winding of the pulse transformer produces a starting pulse through a secondary winding of the pulse transformer. The starting pulse is effective for starting the discharge lamp under predetermined conditions including a condition where it is desired to restart the discharge lamp immediately following the discharge lamp being extinguished.