Impact of dimming white LEDs: chromaticity shifts due to different dimming methods

Dyble, Marc; Narendran, Nadarajah; Bierman, Andrew; Klein, Terence R

doi:10.1117/12.625924

Cited by 132 publications

(103 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Marc Dyble intented the PWM scheme for mixed color along with phospher transformed into pure white LED outcome. [7] deals with the method used for dimming color control, current control methods for various dimming intensity of LED.M. M. Sisto overcomes the challenges faced in [7] along with it, maximation in the Color Rendering Index (CRI) which provides a accurate colors over the surface lighted by LED in [9].K.…”

Section: Introductionmentioning

confidence: 99%

“…[7] deals with the method used for dimming color control, current control methods for various dimming intensity of LED.M. M. Sisto overcomes the challenges faced in [7] along with it, maximation in the Color Rendering Index (CRI) which provides a accurate colors over the surface lighted by LED in [9].K. H. Loo proposes bi-level controlling application for the 2D driving of luminosity and pure white color in addition to duty cycle and current variation.…”

Section: Introductionmentioning

confidence: 99%

“…Various factors like change in component operating conditions and aging, the LEDs from the same case endowed by a manufacturer could result in inconsistent color temperature [7]. Most prominently, continuous changes in temperature during operable conditions may leads for notable differences in color appearance [8].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Android Based LIGHTNET for Brightness and Color Temperature Control

Hanchate¹,

Dhonde²

2017

International Journal of Advanced Research in Computer and Comm

View full text Add to dashboard Cite

These days, the LEDs used for residential, commercial and industrial sectors puposes could be configured for lively with specific lighting, which provides more efficient outcome. The basic idea is to drive the bi-color stripe (warm white stripe with cool white stripe of LEDs) for precise PWM dimming in the range of 1-10V. The dimming of LED strings is controlled by using the android phone. The most important thing that needs to be taken in consideration for controlling the light level in an energetic way, preserving the desired light level where needed while controlling light to a minimum value. However, the regulation of light intensity (brightness) and colour correlated temperature is obtained by adjusting the PWM dimming for LEDs. PWM signal enables us to attain minimum intensity levels and more linear control of light intensity compared to continuous current dimming methods. Though, accurate LEDs controlling of colors which possess color point maintenance, light intensity control along with color mixing in due with LED device lifespan and changes in temperature at a junction. Smart with efficient lighting evolves from the traditional lighting control system with feedback from integrated sensors. In order to achieve the goal of accurate color mixing of two LED strings (warm and cool white LEDs), the closed loop non-linear feedback control method is adopted instead of a linear control method.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Android Based LIGHTNET for Brightness and Color Temperature Control

Hanchate¹,

Dhonde²

2017

International Journal of Advanced Research in Computer and Comm

View full text Add to dashboard Cite

show abstract

“…Dimming decreases the power consumption and may increase the lifetime of LEDs, as heat losses are reduced [30]. A lower operating temperature may also result to possible colour variations, especially in RGB-LEDs, as each semiconductor material reacts differently to temperature changes [37].…”

mentioning

confidence: 99%

“…Therefore, LEDs are usually dimmed by modifying the input current. There are two different dimming methods: amplitude modulation and pulse-width modulation (PWM) [37]. Dimming decreases the power consumption and may increase the lifetime of LEDs, as heat losses are reduced [30].…”

mentioning

confidence: 99%

Electrical efficiency study of alternating current and direct current power topologies in office building with integrated photovoltaics in Matlab-Simulink environment

Viitanen

Halonen

2014

Journal of Renewable and Sustainable Energy

View full text Add to dashboard Cite

Ene rgy e ffic ie nt l igh t ing syst e ms in buil dings w it h int e grat e d ph o t o vo l t aic s J a nne V i i t a ne n D O C T O R A L D I S S E R T A T I O N SAalto University publication series DOCTORAL DISSERTATIONS 18/2015 Energy efficient lighting systems in buildings with integrated photovoltaics Janne Viitanen A doctoral dissertation completed for the degree of Doctor of Science (Technology) to be defended, with the permission of the Aalto University School of Electrical Engineering, at a public examination held at the lecture hall S1 of the school on 6 March 2015 at 12. Aalto University School of Electrical Engineering Department of Electrical Engineering and Automation Lighting Unit AbstractThe goal of this thesis was to study how a building integrated photovoltaic system, choice of lighting technology and the selected system voltage affect the energy efficiency of an office building. The quality of the lighting was considered also, as it is essential that users accept the lighting.The energy production of photovoltaic system (PV) was evaluated in Southern Finland through onsite PV measurements from several different compass points and tilt angles during 2010-2013. Based on the measurements, the PV system was sized to provide energy for lighting and office appliances. The energy efficiency of the devices had considerable effect on the sizing of the PV system. The seasonal variations in the PV production were considerable, as only few per cent of the summer time insolation was available during the winter.The energy efficiency and quality of lighting was studied. Fluorescent lighting (FL) and LED lighting were compared, as they are the most used options in offices today. Lighting measurements and a user study was conducted. Different illuminance levels and correlated colour temperatures (CCT) were studied. The studied parameters included glare, reading task performance, identification of detail, colour naturalness and pleasantness, illuminance level sufficiency and pleasantness, pleasantness of the lighting in general and naturalness of the shadows. The subjects also set their own preferred illuminance levels and CCTs. No major differences were found in the subjective preferences at equal illuminance levels between luminaire types. On average, an illuminance level around 600 lx and a CCT around 4000 K were preferred. LEDs were found more energy efficient than FLs and the difference increased when the luminaires were dimmed.In the last part of the research the electricity consumption of an office building was compared with system voltages 12 VDC, 24 VDC, 48 VDC and 230 VAC through computer simulations in a Matlab-Simulink environment. It was found that 230 VAC was the most energy efficient option as a general system voltage, with the selected components and system variables. The 24 VDC was the most energy efficient option with fluorescent lighting and the 48 VDC with LED lighting, if only the lighting system was considered. Aurinkosähkön tuotantoa Etelä-Suomessa tutkittiin mittausten avulla eri il...

show abstract

Electrical model formulation for multicolor light‐emitting diode modules and its application to design dimmable driver

Bakshi¹,

Roy

2021

Circuit Theory & Apps

View full text Add to dashboard Cite

A multicolor light-emitting diode (LED) module comprises LED chips of more than one type or color and is frequently used for spectrally tunable lighting applications. In this paper, electrical models of such multicolor LED modules are formulated taking two basic circuit configurations into account, namely, (i) conventional, where a parallel string is made of one particular LED type, and (ii) nonconventional, where a parallel string is composed of different LED types. For deriving the model equations, the basic exponential model of a single LED chip has been applied, which is experimentally found to be the suitable option out of the four existing models, namely, linear, parabolic, exponential, and modified Shockley models. The formulated models are experimentally validated, results of which show maximum deviations of 4.71% and 4.19% from the measured data in the nonlinear and the linear operating regions, respectively. The formulated models are utilized to design dimmable, isolated LED drivers for red-green-blue (R-G-B) LED module. Performance evaluation of the drivers is conducted in Matlab-Simulink. The results reveal the satisfactory operation of the LED modules in terms of current and power regulation, branch current matching, and fast response and thus establish the effectiveness of the proposed algorithm.

show abstract

Impact of dimming white LEDs: chromaticity shifts due to different dimming methods

Cited by 132 publications

References 6 publications

Android Based LIGHTNET for Brightness and Color Temperature Control

Android Based LIGHTNET for Brightness and Color Temperature Control

Electrical efficiency study of alternating current and direct current power topologies in office building with integrated photovoltaics in Matlab-Simulink environment

Electrical model formulation for multicolor light‐emitting diode modules and its application to design dimmable driver

Contact Info

Product

Resources

About