Journal of the Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회논문지)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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Design of the High Brightness LED Driver IC with Enhanced the Output Current Control Function

출력전류 제어 기능이 향상된 고휘도 LED 구동 IC 설계

  • Song, Ki-Nam (Department of Electronic Engineering, Gyeongsang National University) ;
  • Han, Seok-Bung (Department of Electronic Engineering and Engineering Research Institute, Gyeongsang National University)
  • 송기남 (경상대학교 전자공학과) ;
  • 한석붕 (경상대학교 전자공학과, 경상대학교 공학연구원)
  • Received : 2010.05.17
  • Accepted : 2010.07.23
  • Published : 2010.08.01
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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.

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References

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