Patent ID: 6329754
Filing Date: 2001-12-11
Classification: B60Q,G01R

Abstract:
Diagnostic system for a ballast of a high-pressure gas discharge lamp of a motor vehicle, said system including said ballast and a light control module, with the light control module connecting the ballast to an operating voltage source (UB) via a supply line (V) extending between said light control module and ballast and monitoring on said supply line (V) a current reception of the ballast, wherein said ballast and said light control module are spatially separated from one another, said ballast including a voltage converter for supplying voltage to the high-pressure gas discharge lamp, a safety circuit for recognizing failed functions of the ballast and the high-pressure gas discharge lamp, which safety circuit turns the voltage converter off in case of fault, and a diagnostic circuit, which generates a fault signal in case of fault; wherein, in case of a fault, the diagnostic circuit of the ballast modulates the current reception of the ballast on said supply line (V), using a switchable current sink (Tr, R.sub.1) as a function of a type of fault that has occurred and the light control module transforms the modulated current into a voltage signal and recognizes the type of fault that has occurred from the voltage signal.