Dimming Techniques Focusing on the Improvement in Luminous Efficiency for High-Brightness LEDs
نویسندگان
چکیده
The pulse width modulation (PWM) dimming mode features good linearity and has been widely used for driving high-brightness light-emitting diodes (HBLEDs), in which the brightness change is reached by modulating duty cycle of signal to regulate average current flowing through LEDs. However, current-illuminance characteristic curve most LEDs nonlinear nature. Namely, under same lighting power fed, conventional PWM cannot make LED exert its best luminous efficiency (LE) specified datasheets. This paper focuses on study further improving efficacy via manipulation. Thereby, two multilevel techniques with varied voltage sensing resistance are presented. With limited capability, proposed strategies can efficiently raise flux ratio without increasing consumption. A prototype constructed a 115 W HBLED driver developed devised schemes realized digital controller (DSC). Experimental results exhibited illuminance-power curves CIE1931 CIE1976 chromaticity diagrams given validate theoretical derivation effectiveness. Compared dimming, illuminance, output respectively reduced 17.08% 13.17%; improvement illuminance 13.66% 11.17%, respectively. In addition, entire LE boost increased 21.36% 16.37%.
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ژورنال
عنوان ژورنال: Electronics
سال: 2021
ISSN: ['2079-9292']
DOI: https://doi.org/10.3390/electronics10172163