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:
Oct. 09, 2001
Filed:
Jan. 13, 2000
Wolfgang Daub, Anroechte, DE;
Hella KG Hueck & Co., Lippstadt, DE;
Abstract
A ballast for a high-pressure gas discharge lamp of a motor vehicle has: a primary pulsed direct-voltage converter including a conversion transformer, a primary-side converter switch (switching transistor), and a secondary-side rectifier circuit; an H-bridge circuit and an ignition circuit downstream of the direct-voltage converter; a pulse-width modulator whose output signal is applied to a control input of the primary-side convert switch; and a regulator whose output signal value is applied to an input of the pulse-width modulator and determines a pulse width of an output signal generated by the pulse-width modulator. In order to obtain a particularly-reliable ignition of the high-pressure gas discharge lamp, even when an operating voltage is reduced, the regulator controls the pulse width of the output signal generated by the pulse-width modulator as a function of a level of the operating voltage, specifically such that as the operating voltage decreases, an output voltage of the direct-voltage converter is increased.