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US 6,646,390 B2Granted
EOL detection with integrated filament interrogation
AssigneePatent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH
InventorsMartin Grabner, Markus Heckmann
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Abstract
The invention relates to a novel operating circuit for a low-pressure discharge lamp 1 with early EOL detection via a measurement of the DC voltage between the electrodes 2, 3. In this case, an electrode interrogation can be carried out by checking a respective connection via the electrodes 2, 3 to a respective reference potential.
Claims11
An operating circuit for a low-pressure discharge lamp (1, 1′) with lamp electrodes (2, 3, 2′, 3′) and an EOL detection circuit (4-13) for early detection of an expected electrode failure,
- characterized in that the EOL detection circuit (4-13) can measure the DC voltage between the electrodes (2, 3, 2′, 3′) in order to carry out the early detection with the aid of the measured DC voltage,
- and the EOL detection circuit (4-13) has an electrode interrogation function,
- the EOL detection circuit (4-13) being connected to in each case a first terminal of at least one electrode (2, 3, 2′, 3′) whose other second terminal is connected to a reference potential (12) such that an electrode interrogation can be carried out by checking the electric connection via the electrode (2, 3, 2′, 3′) to the reference potential (12).
Dependencies are inferred from the claim text.