OPERATING CIRCUIT FOR A DIELECTRICALLY IMPEDED DISCHARGE LAMP HAVING AN OVERVOLTAGE PROTECTION CIRCUIT

摘要

The circuit has an inductive converter for coupling power into the lamp, a switching transistor in a supply line to the converter and an overvoltage protection circuit. The operating circuit applies at least one test pulse to the converter for a re-start of lamp operation that is made too small to damage the switching transistor and the overvoltage protection circuit responds to the voltage produced at the transistor by the test pulse if no lamp is present and does not respond if a lamp is present. Independent claims are also included for the following: (A) an illumination system with an operating circuit and discharge lamp (B) a monitor with an inventive illumination system (C) and a method of igniting a dielectrically inhibited discharge lamp.