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Article: Bilevel current driving technique for LEDs

TitleBilevel current driving technique for LEDs
Authors
KeywordsBilevel current
Buck converter
Control
LED
Luminous efficacy
Issue Date2009
Citation
Ieee Transactions On Power Electronics, 2009, v. 24 n. 12, p. 2920-2932 How to Cite?
AbstractThe significant improvements recently achieved in LED technology in terms of lifetime, luminous efficacy, power rating, and color property render LED one of the most promising candidates to replace conventional light sources in various residential and industrial applications. The rapid advancement in the device characteristics has simultaneously stimulated interests in developing efficient LED drivers with optimized control circuitries. The two conventional techniques currently employed in most LED drivers, namely the amplitude-mode and pulsewidth modulation (PWM) mode driving techniques, suffer from the disadvantage that high luminous efficacy in the amplitude mode has to be traded for control flexibility in the PWM mode and vice versa. In this paper, a method is proposed to improve the luminous efficacy of conventional PWM-mode driving technique while retaining their control flexibility by introducing a dc-offset component into the PWM current. Two LEDs were used in the experimental verifications. Improvements of 17.6% and 18.1% on average were measured by maintaining a dc offset of 100 and 200 mA, respectively, in the LED current. Further improvement can be achieved by increasing the dc-offset current. The main tradeoff is the reduction of the dynamic range over which the average LED current can be controlled. For a given set of performance criteria, the proposed method offers designers of LED drivers the flexibility of balancing between luminous efficacy and dynamic range for control. © 2006 IEEE.
Persistent Identifierhttp://hdl.handle.net/10722/148905
ISSN
2015 Impact Factor: 4.953
2015 SCImago Journal Rankings: 3.005
ISI Accession Number ID
Funding AgencyGrant Number
University Grants Committee of the Hong Kong Special Administrative RegionPolyU 5272/07E
Funding Information:

This work was supported by the University Grants Committee of the Hong Kong Special Administrative Region, Research Grant Council Earmarked Research Grant (ERG) PolyU 5272/07E. A shortened version of this paper was presented at the IEEE Energy Conversion Congress and Exposition (ECCE), San Jose, CA, USA, September 20-24, 2009. Recommended for publication by Associate Editor M. Alonso.

References

 

DC FieldValueLanguage
dc.contributor.authorLun, WKen_HK
dc.contributor.authorLoo, KHen_HK
dc.contributor.authorTan, SCen_HK
dc.contributor.authorLai, YMen_HK
dc.contributor.authorTse, CKen_HK
dc.date.accessioned2012-06-20T06:16:14Z-
dc.date.available2012-06-20T06:16:14Z-
dc.date.issued2009en_HK
dc.identifier.citationIeee Transactions On Power Electronics, 2009, v. 24 n. 12, p. 2920-2932en_HK
dc.identifier.issn0885-8993en_HK
dc.identifier.urihttp://hdl.handle.net/10722/148905-
dc.description.abstractThe significant improvements recently achieved in LED technology in terms of lifetime, luminous efficacy, power rating, and color property render LED one of the most promising candidates to replace conventional light sources in various residential and industrial applications. The rapid advancement in the device characteristics has simultaneously stimulated interests in developing efficient LED drivers with optimized control circuitries. The two conventional techniques currently employed in most LED drivers, namely the amplitude-mode and pulsewidth modulation (PWM) mode driving techniques, suffer from the disadvantage that high luminous efficacy in the amplitude mode has to be traded for control flexibility in the PWM mode and vice versa. In this paper, a method is proposed to improve the luminous efficacy of conventional PWM-mode driving technique while retaining their control flexibility by introducing a dc-offset component into the PWM current. Two LEDs were used in the experimental verifications. Improvements of 17.6% and 18.1% on average were measured by maintaining a dc offset of 100 and 200 mA, respectively, in the LED current. Further improvement can be achieved by increasing the dc-offset current. The main tradeoff is the reduction of the dynamic range over which the average LED current can be controlled. For a given set of performance criteria, the proposed method offers designers of LED drivers the flexibility of balancing between luminous efficacy and dynamic range for control. © 2006 IEEE.en_HK
dc.languageengen_US
dc.relation.ispartofIEEE Transactions on Power Electronicsen_HK
dc.subjectBilevel currenten_HK
dc.subjectBuck converteren_HK
dc.subjectControlen_HK
dc.subjectLEDen_HK
dc.subjectLuminous efficacyen_HK
dc.titleBilevel current driving technique for LEDsen_HK
dc.typeArticleen_HK
dc.identifier.emailTan, SC:sctan@hku.hken_HK
dc.identifier.authorityTan, SC=rp01606en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1109/TPEL.2009.2021687en_HK
dc.identifier.scopuseid_2-s2.0-74349117243en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-74349117243&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume24en_HK
dc.identifier.issue12en_HK
dc.identifier.spage2920en_HK
dc.identifier.epage2932en_HK
dc.identifier.isiWOS:000273136800025-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridLun, WK=35230435400en_HK
dc.identifier.scopusauthoridLoo, KH=7003558724en_HK
dc.identifier.scopusauthoridTan, SC=26642772000en_HK
dc.identifier.scopusauthoridLai, YM=7401512093en_HK
dc.identifier.scopusauthoridTse, CK=7103295097en_HK

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