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:
Feb. 14, 2012
Filed:
Jun. 20, 2007
Michael Haubmann, Vienna, AT;
Michael Haubmann, Vienna, AT;
Arnold & Richter Cine Technik GmbH & Co. Betriebs KG, Munich, DE;
Abstract
A method for driving series-connected light-emitting diodes of an illumination device, in particular an illumination device for film, video and photographic recordings with a pulse-width-modulation of the light-emitting diode current, is provided. In the method the pulse-width-modulated light-emitting diode current is detected and a current sensor signal is derived and fed to a microprocessor, which outputs a drive signal for the pulse-width-modulation and for the setting of the light-emitting diode voltage applied to the light-emitting diodes, depending on the detected current sensor signal. The current-time integral of the pulse-width-modulated light-emitting diode current flowing through the light-emitting diodes is determined and a controllable voltage source for setting the light-emitting diode voltage is driven in such a way that a predetermined pulse-width-modulated light-emitting diode current flows through the light-emitting diodes.