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http://dx.doi.org/10.4313/JKEM.2010.23.8.593

Design of the High Brightness LED Driver IC with Enhanced the Output Current Control Function  

Song, Ki-Nam (Department of Electronic Engineering, Gyeongsang National University)
Han, Seok-Bung (Department of Electronic Engineering and Engineering Research Institute, Gyeongsang National University)
Publication Information
Journal of the Korean Institute of Electrical and Electronic Material Engineers / v.23, no.8, 2010 , pp. 593-600 More about this Journal
Abstract
In this paper, High brightness LED (light-emitting diodes) driver IC (integrated circuit) using new current sensing circuit is proposed. This LED driver IC can provide a constant current with high current precision over a wide input voltage range. The proposed current-sensing circuit is composed of a cascode current sensor and a current comparator with only one reference voltage. This IC minimizes the voltage stress of the MOSFET (metal oxide semiconductor field effect transistor) from the maximum input voltage and has low power consumption and chip area by using simple-structured comparator and minimum bias current. To confirm the functioning and characteristics of our proposed LED driver IC, we designed a buck converter. The LED current ripple of the designed IC is in ${\pm}5%$ and a tolerance of the average LED current is lower than 2.43%. This shows much improved feature than the previous method. Also, protections for input voltage and operating temperature are designed to improve the reliability of the designed IC. Designed LED driver IC uses 1.0 ${\mu}m$ X-Fab. BiCMOS process parameters and electrical characteristics and functioning are verified by spectre (Cadence) simulation.
Keywords
High brightness LED driver; Current sensing circuits; PCC; HCC; Current precision;
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