DocumentCode :
2283053
Title :
Implementation of bi-level current driving technique for improved efficacy of high-power LEDs
Author :
Lun, Wai-Keung ; Loo, K.H. ; Tan, Siew-Chong ; Lai, Y.M. ; Tse, Chi K.
Author_Institution :
Dept. of Electron. & Inf. Eng., Hong Kong Polytech. Univ., Kowloon, China
fYear :
2009
fDate :
20-24 Sept. 2009
Firstpage :
2808
Lastpage :
2814
Abstract :
Presently, amplitude mode (DC mode) and pulsewidth 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.
Keywords :
LED displays; lighting; -level current driving technique; DC mode; DC-offset; PWM driving technique; amplitude mode; high-power LED; pulsewidth modulation; Light-emitting diode (LED); bi-level current; buck converter; control; dimming; luminous efficacy;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Energy Conversion Congress and Exposition, 2009. ECCE 2009. IEEE
Conference_Location :
San Jose, CA
Print_ISBN :
978-1-4244-2893-9
Electronic_ISBN :
978-1-4244-2893-9
Type :
conf
DOI :
10.1109/ECCE.2009.5316560
Filename :
5316560
Link To Document :
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