U.S. Philips Corporation

Ralf Schafer

Lodewijk H Meessen

Petrus H Antonis

Hilbert Palmers

Steven Kemmink

A circuit arrangement suitable for operating a high-pressure discharge lamp (80) in conjunction with a controlled current limiter (6) by means of a control signal which is at least composed of the sum of a lamp-voltage-dependent signal part and a lamp-current-dependent signal part. The invention, the absolute value of the lamp-current-dependent signal part is chosen to be smaller than the absolute value of the lamp-voltage-dependent signal part. The circuit arrangement provides a rapid control, which keeps the lamp voltage substantially constant.

Operating circuit for a high-pressure discharge lamp

A high-pressure sodium vapor discharge lamp having a ceramic discharge vessel, which has over a length L a substantially constant inner diameter and in which electrodes are arranged opposite to each other at a relative distance D. The lamp emits white light during operation and consumes a power of at most 50 watts. The lamp has a high efficiency and good color rendering due to the fact that D/L.ltoreq.0.5.

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Eindhoven, Netherlands

Ralf Schafer