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. 21, 2017
Filed:
Apr. 05, 2011
Kevin Peter D'angelo, Carmel, CA (US);
Kevin Peter D'Angelo, Carmel, CA (US);
ADVANCED ANALOGIC TECHNOLOGIES INCORPORATED, San Jose, CA (US);
Abstract
An active clamp current sink is used to voltage protect a low voltage rated, high power current sink that drives illumination current through a string of serially connected LEDs. When the LEDs are turned off as part of a PWM configuration, the forward voltage on the LEDs falls, and the voltage presented to the low voltage rated, high power current sink rises. The active clamp current sink monitors the voltage across the high power current sink and ensures that an adequate current flows through the LEDs. This minimally adequate current maintains a sufficiently large forward voltage through the LEDs, and therefore a sufficiently small voltage is presented to the high power current sink.