- Volume 29 Issue 2
This paper proposes a dimming method and a hybrid LED driving circuit suitable for the ultra high definition (UHD) broadcasting. There are major two problems during the dimming control for traditional LED broadcast lightings; one is a flicker that occurred when camera filming to these lightings, and the other is that linear control is impossible for LED luminous intensity under 10% due to LED electrical characteristics. The proposed dimming method and the driving circuit are designed to solve two problems simultaneously. For high level dimming control region from 10 to 100%, the analog control method was applied to the switching regulator constructed by MOSFET operated in the saturation region. For low level dimming control region under 10%, the fast PWM control method with the linear regulator constructed by MOSFET in the ohmic region was used. We verified experimentally that the dimming method is able to control the luminous intensity linearly from 1 to 100% and the flicker disappears on images taken by the charge coupled device (CCD) and the complementary metal oxide semiconductor (CMOS) cameras. Therefore, the proposed method is suitable for the UHD broadcasting.
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- Sook-Hee Cho, Dong-San Jeon, Jin-Soo Choi, "ICT Standard & Certification TTA Journal", TTA, Vol.140, pp.49-54, Apr, 2012.
- M. Dyble, N. Narendran, A. Bierman, and T. Klein, "Impact of Dimming White LEDs: Chromaticity Shifts Due to Different Dimming Methods," Fifth International Conference on Solid State Lighting, Proceedings of the SPIE 5941, pp. 291-299, Sep, 2005.
- Guang-Xu Jin, Sung-Ho Kang, Ki-Sang Hong, "Prediction of Flicker for PDP Devices", IEIE, Vol.42-SP, No.2, pp.9-18, Mar, 2005.
- Philips Lumileds, "LUXEON Rebel General Purpose Datasheet DS64", 2011.
- Kwang-Hyun Jung, Dong-Seok Shin, Chong-Yeon Park, "The analysis of flickering effect for LED stage lighting systme", 42th KIEE Summer Conference, pp.1195-1196, Jul, 2011.
- Chong-Yeun Park, Jae-Wook Song, Jin-Wan Yoo, "The Reduction Method of Strings Current Unbalancing in LED Lighting Driving System", KIIEE, Vol.27, No.5, pp.26-32, May, 2013.
연구 과제 주관 기관 : 대학산업기술지원단