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:
Jan. 20, 2009
Filed:
Jun. 28, 2004
Lukas Haener, Duebendorf, CH;
Juerg Fries, Zurich, CH;
Lukas Haener, Duebendorf, CH;
Juerg Fries, Zurich, CH;
DSP Group Switzerland AG, Zurich, CH;
Abstract
The invention relates to a device for lighting at least one light emitting diode to be supplied with predefined minimum forward voltage and maximum current. It comprises: —voltage supply means for supplying voltage to the light emitting diode, —a pulse generator for generating a cyclic pulse signal having predefined on-times and off-times, —a switch, controlled by the pulse generator to be turned on during said on-times to short-circuit the light emitting diode and turned off during said off-times, —an inductive device for increasing the forward voltage over the light emitting diode when the switch is turned off, so that said forward voltage gets higher that the minimum forward voltage and for decreasing said forward voltage when the switch is turned on, so that the current through the light emitting diode remains below the maximum current.