Patent ID: 7045973
Filing Date: 2006-05-16
Classification: H05B

Abstract:
1. An operating circuit for a dielectrically impeded discharge lamp having an inductive converter for inputting power to the lamp, a switching transistor in a line supplying current to the converter, and an overvoltage protection circuit for detecting a voltage across the switching transistor and preventing lamp operation if a voltage which is above a predetermined threshold value is detected, in order to prevent the switching transistor being destroyed by energy input from the converter in the event of a lamp being absent, and the operating circuit being designed to apply, when restarting lamp operation, initially at least one test power pulse to the converter which is so small that destruction of the switching transistor as a result of this test power pulse is ruled out, and the overvoltage protection circuit responds to a voltage, produced by this test power pulse, across the switching transistor when no lamp is connected and does not respond when the lamp is connected.