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:
Sep. 28, 2004
Filed:
Aug. 21, 2002
Alan Michael Rooke, Northville, MI (US);
Ibrahim S. Kandah, Canton, MI (US);
Freescale Semiconductor, Inc., Austin, TX (US);
Abstract
A circuit and method for providing closed loop control using constant current switching techniques is disclosed herein. By controlling the current supplied to high intensity light emitting diodes (LEDs) using the techniques and circuits described, high intensity LEDs can be operated at or near their maximum capacity without danger of overloading the LEDs, and without using excess amounts of current. A circuit as described herein, has multiple high side switches, each of which is connected to an LED array. The LED arrays are in turn connected through an inductor to a current switching control section that switches current to ground, or recirculates the current to maintain LED current flow within a desired range.