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:
Aug. 11, 2015
Filed:
Sep. 27, 2013
Applicant:
Shanghai Bright Power Semiconductor Co., Ltd., Shanghai, CN;
Inventors:
Assignee:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B 33/08 (2006.01);
U.S. Cl.
CPC ...
H05B 33/0815 (2013.01);
Abstract
A current ripple canceling light-emitting diode (LED) driver is disclosed. The input current source contains a current ripple. The LED load is connected to the drain of a power switch. The source of the power switch is connected to a current sensing resistor. The gate of the power switch is connected to the output of an operational amplifier. The operational amplifier compares the voltage signal across the current sensing resistor with a dynamic reference voltage. The dynamic reference voltage is adjusted according to the gate or drain voltage of the power switch. The LED load current is controlled to be a nearly no ripple DC current.