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http://dx.doi.org/10.5370/KIEE.2012.61.4.612

Design of an Active Current Regulator for LED Driver IC  

Yun, Seong-Jin (강원대 공대 전기전자공학과)
Oh, Tak-Jun (강원대 공대 전기전자공학과)
Jo, A-Ra (강원대 공대 전기전자공학과)
Ki, Seok-Lip (강원대 공대 전기전자공학과)
Hwang, In-Chul (강원대 전기전자공학과)
Publication Information
The Transactions of The Korean Institute of Electrical Engineers / v.61, no.4, 2012 , pp. 612-616 More about this Journal
Abstract
This paper presents an active current regulator for LED driver IC. The proposed driver circuit is consists of DC-DC converter for supplying constant DC voltage to LED, active current regulator for compensating channel-to-channel current error from LED strings and feedback circuit for controlling duty ratio of the converter. The proposed active current regulator senses current of LED channels by equalizing both $V_{DS}$ and $V_{GS}$ at LED current control transistor. Because the proposed circuit directly measures the LED channel current without a sensing resistor and regulates all channel with same regulation loop, the power consumption and the current error are much small compared with previous works. The measured maximum efficiency of overall LED driver IC is approximately 94% and current error of LED channel-to-channel is under ${\pm}1.3%$. The proposed LED driver IC is fabricated Dongbu 0.35um BCD process.
Keywords
Active current regultor; Current mirror; LED driver IC;
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