Implementation of Bi-level current driving technique for improved efficacy of high-power LEDs

Wai Keung Lun, Ka Hong Loo, Siew Chong Tan, Y. M. Lai, Chi Kong Tse

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

6 Citations (Scopus)


Presently, amplitude mode (DC mode) and pulse-width modulation (PWM) represent the two main driving techniques used in LED drivers. The dimming function with PWM driving technique is attractive although lower luminous efficacy and stresses on the LEDs due to pulsating power are the disadvantages in comparison to amplitude mode. This paper introduces a current driving technique to improve the luminous efficacy over the conventional PWM technique while maintaining the dimming capability. This is achieved by introducing a DC-offset into the conventional PWM current waveform. It is found that the luminous efficacy increases with increasing DC-offset while the stresses due to pulsating power are reduced. Implementation and verification of the proposed driving technique using a prototype driver are presented.
Original languageEnglish
Title of host publication2009 IEEE Energy Conversion Congress and Exposition, ECCE 2009
Number of pages7
Publication statusPublished - 28 Dec 2009
Event2009 IEEE Energy Conversion Congress and Exposition, ECCE 2009 - San Jose, CA, United States
Duration: 20 Sep 200924 Sep 2009


Conference2009 IEEE Energy Conversion Congress and Exposition, ECCE 2009
Country/TerritoryUnited States
CitySan Jose, CA


  • Bi-level current
  • Buck converter
  • Control
  • Dimming
  • Light-emitting diode (LED)
  • Luminous efficacy

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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