CIRCUIT ARRANGEMENT FOR OPERATING A HIGH-PRESSURE SODIUM DISCHARGE LAMP

摘要

Circuit arrangement for operating a high pressure sodium discharge lamp. The invention relates to a circuit arrangement suitable for operating at a supply voltage Vn a high-pressure sodium discharge lamp (4) having a lamp voltage V1a in conjunction with a current limiter circuit (3) and a first controlled semiconductor switching element (1). According to the invention, the circuit arrangement comprises - a first part for comparing a proportional part of the lamp voltage V1a with a reference voltage Vr and - a second part for comparing a proportional part of the supply voltage Vn with the resultant of the first comparison. With the circuit arrangement, it is possible to operate the lamp in such a manner that the lamp voltage V1a is substantially constant.