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. 17, 2017
Filed:
Oct. 25, 2013
Cree, Inc., Durham, NC (US);
Everett Bradford, Apex, NC (US);
Cree, Inc., Durham, NC (US);
Abstract
A lighting device employs an array of LEDs as a lighting source. The array of LEDs may be coupled in series between a power supply node and ground. In order to determine whether the input drive signal to the array of LEDs is a pulse width modulated (PWM) signal or a linear signal, the voltage across the string of LEDs is sampled and stored in a cyclical buffer. The variance of the samples stored in the cyclical buffer is then calculated and used to determine whether the input signal provided to the string of LEDs at the power supply node is a PWM signal or a linear signal. In one embodiment, the variance is compared to a predetermined threshold value to determine whether the input signal is a PWM signal or a linear signal.