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:
Mar. 10, 2015
Filed:
Apr. 29, 2014
Linear Technology Corporation, Milpitas, CA (US);
Keith D. Szolusha, Saratoga, CA (US);
Joshua W. Caldwell, Los Gatos, CA (US);
Linear Technology Corporation, Milpitas, CA (US);
Abstract
In a method for controlling a current regulator for dimming an LED load, an adjustable delay circuit generates a delayed second dimming signal from an original first dimming signal. The second dimming signal has a duty cycle that controls the LED ON-time and LED OFF time at a fixed frequency. An ON-time pulse of the first dimming signal starts a pre-charging of the regulator's inductor to approximately the inductor current previously detected at the end of the previous ON-time of the LEDs. The pre-charging ends at the leading edge of the delayed ON-time pulse of the second dimming signal. The second dimming signal controls the regulator to only supply current to the LED load during the LED ON-time. The delay time is adjusted by a feedback loop. Therefore, the current pulse magnitudes applied to the LED load are constant at every duty cycle even with very low duty cycles.