High power light-emitting diode junction temperature determination from current-voltage characteristics

Keppens, Arno; Ryckaert, Wouter; Deconinck, Geert; Hanselaer, Peter

doi:10.1063/1.3009966

Cited by 117 publications

(68 citation statements)

References 11 publications

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“…(1) and (2) can be expressed as a linear approximation when T ) 0 K. 18 Since the temperature range during our measurements was between 279 K and 398 K, the linearized band gap energy can be approximated as…”

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confidence: 99%

Temperature invariant energy value in LED spectra

Baumgartner

Vaskuri

Kärhä

et al. 2016

Applied Physics Letters

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Relative emission spectra of light-emitting diodes (LEDs) depend on the junction temperature. The high-energy region of the emission spectrum can be modelled with Maxwell-Boltzmann distribution as a function of energy and junction temperature. We show that according to the model and our experiments, the normalized emission spectra at different junction temperatures intersect at a unique energy value. The invariant intersection energy exists for many types of LEDs and can be used to determine the alloy composition of the material. Furthermore, the wavelength determined by the intersection energy can be used as a temperature invariant wavelength reference in spectral measurements.

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mentioning

confidence: 99%

Temperature invariant energy value in LED spectra

Baumgartner

Vaskuri

Kärhä

et al. 2016

Applied Physics Letters

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“…The behavior depends on the particular HB-LED that is used, but certain general characteristics can be identified [20]- [22]. It can be assumed that the light intensity is proportional to the current.…”

Section: A Driving Requierementsmentioning

confidence: 99%

Performance evaluation of a VLC transmitter based on the split of the power

Rodríguez

Aller

Lamar

et al. 2018

2018 IEEE Applied Power Electronics Conference and Exposition (APEC)

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Abstract-Visible Light Communication (VLC) has gained relevance during last years. It consists in using High-Brightness LEDs (HB-LEDs) both for lighting and for transmitting information changing the light intensity rapidly. However, there are some bottlenecks that are slowing down the deployment of this technology. One of the most important problems is that the HB-LED drivers proposed for addressing high data rates in VLC achieve poor power efficiency. Since these HB-LED drivers must be able to reproduce fast current waveforms, the use of Linear Power Amplifiers (LPAs) has been adopted, which clearly damage the power efficiency of HB-LED lighting. In order to alleviate this problem, a HB-LED driver made up of two DC-DC power converters is presented in this work. One of them is responsible for performing the communication functionality by operating at high switching frequency (10 MHz), whereas the second one fulfills the illumination functionality by ensuring a certain biasing point. The split of the power allows to minimize the power delivered by the fast-response DC-DC power converter. Thus, the efficiency can be maximized for scenarios with changing conditions (i.e., mobile transmitter and/or receiver, presence of mobile obstacles, etc.). In this sense, how the lighting level and the communication signal power affect both the power efficiency and the communication efficiency is deeply analyzed. The implemented prototype achieves an overall efficiency around 90%. In addition, the proposed VLC transmitter is able to reproduce a wide range of digital modulation schemes, including Orthogonal Frequency Division Multiplexing (OFDM).

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“…4 also shows the dependence of the voltage waveform on the junction temperature of the HB-LEDs (TJ). Basically, VK falls when TJ rises while RD remains constant [41]- [43]. Consequently, ensuring a certain voltage level does not guarantee the desired lighting level.…”

Section: Driving Hb-leds For Performing Vlcmentioning

confidence: 99%

Power-Efficient VLC Transmitter Based on Pulse-Width Modulated DC–DC Converters and the Split of the Power

Rodríguez

Lamar

Miaja

et al. 2019

IEEE Trans. Power Electron.

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Abstract-Visible Light Communication (VLC) has gained relevance during the last years. It consists in using High-Brightness LEDs (HB-LEDs) both for lighting and for transmitting information by changing the light intensity rapidly. However, there are some bottlenecks that are slowing down the deployment of this technology. One of the most important problems is that the HB-LED drivers proposed for addressing high data rates in VLC achieve poor power efficiency. Since these HB-LED drivers must be able to reproduce fast current waveforms, the use of Linear Power Amplifiers (LPAs) has been adopted, which clearly damages the power efficiency of HB-LED lighting.In order to alleviate this problem, a HB-LED driver made up of two DC-DC power converters is presented in this work. One of them is responsible for performing the communication functionality by operating at high switching frequency (10 MHz), whereas the second converter fulfills the illumination functionality by ensuring a certain biasing point. The split of the power allows us to minimize the power delivered by the fast-response DC-DC power converter, which suffers from high switching losses. Thus, the overall efficiency can be maximized for each particular communication scenario and for scenarios with changing conditions (i.e., mobile transmitter and/or receiver, presence of mobile obstacles, etc.). In this sense, how the lighting level and the communication signal power affect both the power efficiency and the communication efficiency is deeply analyzed in the experimental section. The implemented prototype achieves an overall efficiency around 90%. In addition, the proposed VLC transmitter is able to reproduce a wide range of digital modulation schemes, including the preferred one for wireless communications:Orthogonal Frequency Division Multiplexing (OFDM). Index Terms-High switching frequency, Orthogonal Frequency Division Multiplexing (OFDM), Visible Light Communication (VLC), High-Brightness LED (HB-LED), outputseries connection. I. INTRODUCTIONIRELESS communication is essential for the present and future society. A lot of emerging topics, such as the smart city concept or the development of the smartphones technology, promote the communication between humans and many devices placed into the environment. As a result, the mobile data traffic has grown exponentially during the last decade and it is expected that it keeps growing by 2021 [1]. However, enabling the predicted data traffic is not straightforward because the Radio Frequency (RF) spectrum is close to congestion.Visible Light Communication (VLC) is one of the most promising solutions for alleviating the problem [2]- [5]. It consists in using the High-Brightness LEDs (HB-LEDs) not only for lighting, but also for transmitting information by changing the light intensity rapidly. In this application, the light intensity has a DC component that determines the lighting level and an AC component that represents the transmitted information. Obviously, the light intensity modulation is fast enough to be u...

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High power light-emitting diode junction temperature determination from current-voltage characteristics

Cited by 117 publications

References 11 publications

Temperature invariant energy value in LED spectra

Temperature invariant energy value in LED spectra

Performance evaluation of a VLC transmitter based on the split of the power

Power-Efficient VLC Transmitter Based on Pulse-Width Modulated DC–DC Converters and the Split of the Power

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