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. 19, 2021
Filed:
Dec. 11, 2020
Viza Electronics Pte. Ltd., Charlotte, NC (US);
Jack Lula, Burlington, CA;
Robert Zamora, Huntersville, NC (US);
Viza Electronics Pte. Ltd., Charlotte, NC (US);
Abstract
A dimming and color mixing apparatus for light emitting diodes (LEDs) combines constant current distribution with reduced pulse widths. A current source provides a constant source of LED drive current to at least a pair of switches under command of an LED controller. A predefined fraction of the LED rated current that will ensure uniform light output between the LEDs is selected as a minimum drive current to be supplied from the constant current source. The LED controller causes the switches to provide alternating pulses between at least two channels of LEDs according to a switching rate for color mixing, and the current source decreases the LED drive current linearly for dimming. For dimming levels below the minimum drive current, the LED controller decreases the pulse widths in conjunction with the decreased drive current. In one arrangement, for each LED channel the percentage of a duty cycle for the pulsed current is less by a factor of 10 than the percentage of the relative current from the constant current source. The decreased pulse widths lead to increased peak current driven to the LEDs from the constant current source and helps avoid nonuniform light emission when dimming and color mixing the LEDs.