The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 07, 1993
Filed:
Sep. 21, 1992
Wolfgang Daub, Lippstadt, DE;
Friedrich-Karl Wendt, Salzkotten, DE;
Hella KG Hueck & Co., Lippstadt, DE;
Abstract
A power-supply apparatus, or ballast, for starting and operating a high-pressure gas discharge lamp is fed from a battery and has at least one current- and/or power-controlled voltage converter which is coupled to a high-pressure gas discharge lamp via an ignition device and to a current/power control device via input and output terminals. A comparator of the current/power control device produces a switching signal dependent upon a lamp voltage input signal, and a capacitor, dependent upon the switching signal, is charged with a circuit having a first time constant and discharged with a circuit having a second time constant. The charge voltage of the capacitor is applied to the output to determine the level and duration of additional power supplied to the high-pressure gas discharge lamp after ignition. When the power-supply apparatus is turned off, the capacitor is coupled to a second reference voltage source and is charged by means of the first time constant. The comparator produces, when the power-supply apparatus is switched on, a switching signal when a lamp voltage limit is exceeded.