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EP0445882A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Switching arrangement

Assignee: Koninklijke Philips NV
•
Filing: 1991-03-04
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Granted: —
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Expires: 2011-03-04
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Abstract

Abstract The invention relates to a switching arrangement for operating a high-pressure sodium lamp (1) which radiates white light in stable operating conditions. The switching arrangement is provided with switching means (5) for switching current through the lamp by means of a drive signal generated in a drive circuit (6), which signal is based on a comparison between a reference value C and a drive signal V+βI, in which V is the lamp voltage, I is the lamp current, and β is a constant. According to the invention, C may be adjusted in steps in dependence on the lamp voltage. Thus the duration over which the lamp radiates white light can be prolonged and brought into better accordance with the electrical lamp life.

Inventors

  • 👤 Robertus Antonius Johannes Keijser
  • 👤 Petrus Antonius Maria Weerdesteijn

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-03 20:41
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/36; H05B41/38; H05B41/39; H05B41/392; Y; Y10; Y10S; Y10S315/00; Y10S315/07

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 99 words
A switching arrangement for operating a high-pressure sodium lamp which radiates white light in stable operating conditions, which switching arrangement is provided with switching means for switching current through the lamp by means of a drive signal generated in a drive circuit and derived from a comparison between a reference value C and a drive signal having the form V+βI, where V is the lamp voltage, I is the lamp current, β is a constant, characterized in that the switching arrangement comprises a drive circuit with means for adjusting the reference value C in dependence on the lamp voltage.
Claim 2
Dependent Claim 33 words
A switching arrangement as claimed in Claim 1, characterized in that the means for adjusting the reference value C serve to reduce C when the lamp voltage rises above a preset upper level.
Claim 3
Dependent Claim 35 words
A switching arrangement as claimed in Claim 1 or 2, characterized in that the means for adjusting the reference value C comprise a window comparator for comparing the lamp voltage with the preset upper level.

References Cited (Backward Citations)

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