Special Issue "Latest Developments in LED Drivers"

A special issue of Electronics (ISSN 2079-9292). This special issue belongs to the section "Power Electronics".

Deadline for manuscript submissions: 30 November 2019.

Special Issue Editor

Guest Editor
Prof. Dr. Diego Gonzalez Lamar

Electronic Technology Area of the University of Oviedo, 33204 Gijón, Spain
Website | E-Mail
Interests: power electronics; DC–DC converters; power factor correction; LED drivers (VLC); WBG in power converters

Special Issue Information

Dear Colleagues,

LEDs are increasingly becoming our main source of artificial light in many applications (e.g., street lighting, automotive, residential lighting). This is due to the excellent characteristics of LEDs: Long lifetime, low maintenance requirement, environmental friendliness, luminous efficiency, controllability in both light and color, lack of warm-up period, and reliability.

Due to the fact that LEDs are diodes, it is necessary to control their DC forward current. The piece of equipment fulfilling this task is the called LED drivers. It is important that they do not limit the LED benefits and performances. Therefore, LED drivers must be efficient, compact, and they must operate with a wide input voltage range, comply with very strict regulations, dispose the most limiting component in terms of lifetime that are electrolytic capacitors, and adequately control the output current in order to achieve dimming and equalizing. These requirements have made the driving of LED lamps a challenging topic in power electronics.

The main objective of this Special Issue is to collect the latest developments in LED drivers. Prospective authors are invited to submit original contributions for review and for publication in this Special Issue. Topics of interest include, but are not limited to:

  • Modeling of LED lamps and LED drivers;
  • Efficient AC–DC and DC–DC LED drivers;
  • Power factor correction in AC–DC LED drivers;
  • AC–DC flicker-free LED drivers without electrolytic capacitor;
  • EMI/EMC issues in LED drivers;
  • Efficient dimming in LED drivers;
  • Efficient current equalizing in multiarray LED lamps;
  • Digital control applied to LED drivers;
  • Significant trends in LED lighting applications: Display, indoor, outdoor, architectural, automotive, visible light communication systems, horticulture, etc.

Prof. Dr. Diego Gonzalez Lamar
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Electronics is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (5 papers)

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Research

Open AccessArticle
A Single-Stage LED Streetlight Driver with Soft-Switching and Interleaved PFC Features
Electronics 2019, 8(8), 911; https://doi.org/10.3390/electronics8080911
Received: 10 July 2019 / Revised: 14 August 2019 / Accepted: 15 August 2019 / Published: 18 August 2019
PDF Full-text (2315 KB)
Abstract
This paper presents a single-stage driver with soft-switching and interleaved power-factor correction (PFC) features suitable for light-emitting diode (LED) energy-saving streetlight applications. The proposed LED streetlight driver integrates an interleaved buck-boost PFC converter with coupled inductors and a half-bridge LLC resonant converter into [...] Read more.
This paper presents a single-stage driver with soft-switching and interleaved power-factor correction (PFC) features suitable for light-emitting diode (LED) energy-saving streetlight applications. The proposed LED streetlight driver integrates an interleaved buck-boost PFC converter with coupled inductors and a half-bridge LLC resonant converter into a single-stage power-conversion circuit with reduced voltage stress on the DC-linked capacitor and power switches, and it is suitable for operating at high utility-line voltages. Furthermore, coupled inductors in the interleaved buck-boost PFC converter are operated in discontinuous-conduction mode (DCM) for accomplishing PFC, and the half-bridge LLC resonant converter features zero-voltage switching (ZVS) to reduce switching losses of power switches, and zero-current switching (ZCS) to decrease conduction losses of power diodes. Operational modes and design considerations for the proposed LED streetlight driver are introduced. Finally, a 144 W (36V/4A)-rated LED prototype driver is successfully developed and implemented for supplying a streetlight module and operating with a utility-line input voltage of 220 V. High power factor, low output-voltage ripple factor, low output-current ripple factor, and high efficiency are achieved in the proposed LED streetlight driver. Full article
(This article belongs to the Special Issue Latest Developments in LED Drivers)
Open AccessArticle
Single-Switch LED Post-Regulator Based on a Modified Class-E Resonant Converter with Voltage Clamp
Electronics 2019, 8(7), 798; https://doi.org/10.3390/electronics8070798
Received: 25 June 2019 / Revised: 12 July 2019 / Accepted: 15 July 2019 / Published: 16 July 2019
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Abstract
The strict restrictions imposed both by mandatory regulations and by the recommendations contained in current standards have led to the fact that most commercially available LED ballasts nowadays use two-stage topologies. The first stage is intended to comply with the harmonics standards and [...] Read more.
The strict restrictions imposed both by mandatory regulations and by the recommendations contained in current standards have led to the fact that most commercially available LED ballasts nowadays use two-stage topologies. The first stage is intended to comply with the harmonics standards and the second stage is used to control the LED current and reduce the low frequency ripple. In this work, a new DC–DC resonant converter topology is presented. This topology is derived from a modified Class-E resonant inverter by adding a clamping diode. This diode achieves a double goal: it limits the maximum switch voltage and works as a power recirculating path. This way, the proposed topology behaves as a loss-less impedance placed in series with the LED thus allowing to control the output power. This converter maintains the extremely small switching losses inherent to the Class-E inverter while reducing the voltage stress across the switch. This work presents a simplified design methodology based on the fundamental approach. This methodology was used to design and build a DC–DC post-regulator for a 40 W LED lamp. The results obtained with the laboratory prototype show that this circuit can be used to stabilize and dim the LED current while maintaining very small losses. The measured efficiency was 95.7% at nominal power and above 90% when dimmed down to 25%. Full article
(This article belongs to the Special Issue Latest Developments in LED Drivers)
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Open AccessArticle
Optimization of a Series Converter for Low-Frequency Ripple Cancellation of an LED Driver
Electronics 2019, 8(6), 664; https://doi.org/10.3390/electronics8060664
Received: 8 May 2019 / Revised: 31 May 2019 / Accepted: 10 June 2019 / Published: 12 June 2019
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Abstract
In this paper, the optimization of the power and control stages of a previously proposed topology for an off-line LED electronic driver is presented. The full system avoids the use of electrolytic capacitors at the DC link, therefore increasing the lifespan and [...] Read more.
In this paper, the optimization of the power and control stages of a previously proposed topology for an off-line LED electronic driver is presented. The full system avoids the use of electrolytic capacitors at the D C link, therefore increasing the lifespan and reliability of the driver. As a consequence of having a relatively small capacitance, the D C link operates with a large Low-Frequency ( L F ) voltage ripple. This work presents a design optimization for the power and control stages of a current-fed bidirectional buck converter, operating as the LED current control stage. As this block processes only the A C power arising from the L F voltage ripple, it can increase the system efficiency against the typical two-stage solution. In the original proposal, the main drawback was the high inductor losses due to the resulting large inductor currents and large inductance value. The proposed optimization ensures an enhanced design of the inductor while keeping a constant current through the LEDs. A new optimization methodology is proposed and the theoretical results have been validated in a built prototype for a 40 W LED lamp. Full article
(This article belongs to the Special Issue Latest Developments in LED Drivers)
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Open AccessArticle
Heterogeneous Integration of GaN and BCD Technologies
Electronics 2019, 8(3), 351; https://doi.org/10.3390/electronics8030351
Received: 7 January 2019 / Revised: 12 March 2019 / Accepted: 18 March 2019 / Published: 22 March 2019
Cited by 1 | PDF Full-text (5926 KB) | HTML Full-text | XML Full-text
Abstract
Light-emitting diodes (LEDs) are solid-state devices that are highly energy efficient, fast switching, have a small form factor, and can emit a specific wavelength of light. The ability to precisely control the wavelength of light emitted with the fabrication process enables LEDs to [...] Read more.
Light-emitting diodes (LEDs) are solid-state devices that are highly energy efficient, fast switching, have a small form factor, and can emit a specific wavelength of light. The ability to precisely control the wavelength of light emitted with the fabrication process enables LEDs to not only provide illumination, but also find applications in biology and life science research. To enable the new generation of LED devices, methods to improve the energy efficiency for possible battery operation and integration level for miniaturized lighting devices should be explored. This paper presents the first case of the heterogeneous integration of gallium nitride (GaN) power devices, both GaN LED and GaN transistor, with bipolar CMOS DMOS (BCD) circuits that can achieve this. To validate this concept, an LED driver was designed, implemented and verified experimentally. It features an output electrical power of 1.36 W and compact size of 2.4 × 4.4 mm2. The designed fully integrated LED lighting device emits visible light at a wavelength of approximately 454 nm and can therefore be adopted for biology research and life science applications. Full article
(This article belongs to the Special Issue Latest Developments in LED Drivers)
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Open AccessArticle
Improvement of the Approximation Accuracy of LED Radiation Patterns
Electronics 2019, 8(3), 337; https://doi.org/10.3390/electronics8030337
Received: 21 February 2019 / Revised: 15 March 2019 / Accepted: 18 March 2019 / Published: 20 March 2019
PDF Full-text (2528 KB) | HTML Full-text | XML Full-text
Abstract
For the great variety of light-emitting diodes (LEDs), there exists a wide range of LED radiation patterns. An approach for constructing patterns of higher accuracy is here considered. The latter is required when the design of optoelectronic systems or their optimization is carried [...] Read more.
For the great variety of light-emitting diodes (LEDs), there exists a wide range of LED radiation patterns. An approach for constructing patterns of higher accuracy is here considered. The latter is required when the design of optoelectronic systems or their optimization is carried out analytically. A weighting function is introduced that allows increasing the gradient of the diagram of different widths. It has been selected through mathematical analysis of the emission diagrams of different LEDs used in optoelectronic systems. Based on the least squares method an algorithm is created, and programs are developed in MATLAB environment to estimate the parameters of the approximation function. Its accuracy is evaluated by comparison with the approximation with Lambert source of order n. The results show higher accuracy of the proposed approximation function compared to those obtained by conventional methods. Recommendations on the application of the proposed approach are given. Full article
(This article belongs to the Special Issue Latest Developments in LED Drivers)
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