LEDs

EDN Staff

Information on LEDs (light emitting diodes) and their various applications that runs the gamut from individual LED components to LED light teardowns, as well as in-depth technical design articles, regulatory and industry news, and product features.

Studying the green gap in LED efficiency

Within the green LED spectral range, efficiency deteriorates based on diminishing electron-hole wave function overlap when compared with blue LEDs. Read More...

Details emerge on OLED TVs at CES

As TVs grow paper thin, they require ever-greater energy efficiency, which is the hallmark of OLED technology. Read More...

Why are these LED aisle lights being pulsed?

After snapping a photo of the LEDs lining the edges of a movie theater aisle, this engineer wondered why the lights were being pulsed. Read More...

Clean water courtesy of LEDs

Metal foil-based LEDs being researched at Ohio State University could provide portable sterilization equipment for clean drinking water. Read More...

Cree calls out counterfeit LEDs in patent infringement suit

Cree has filed a patent infringement suit against a distributor of a flashlight that it says uses counterfeit LEDs. Read More...

LED lamp cycles on and off, why?

When an LED flood lamp started cycling, I suspected temperature. Now, how can we find what's the root cause? Read More...

How to design a flyback converter as a front-end for a two-stage LED driver

A two stage LED driver consists of a PFC flyback converter with constant voltage regulation for the front-end followed by a constant current regulating buck stage. Read More...

LED strings driven by current source/mirror

This unusual dual-output current source can, for example, drive LED strings at any desired current ratio. Read More...

The largest LED video display in all of sports

The largest LED video display in sports, engineered by Daktronics, will be housed at the new Mercedes-Benz Stadium, opening next year. Read More...

Medicinal cannabis improves under LED lighting

Here’s interesting information regarding a study of medicinal cannabis and how it does under LED lighting. Read More...

LTC Design Note: 60V Buck-Boost LED driver has up to 98% efficiency, PWM dimming, spread spectrum

LED driver design is highly efficient, flicker-free, minimizes EMI, and plays well in the automotive environment. Read More...

Thermal design: Get the heat out of the electronics

Whether you are designing an LED lamp or an electric drag racer, know your options and the need to get the heat out of the electronics. Read More...

Patent diving: Apple’s OLED plans

Sometimes it’s hard to get a pulse on how certain technical challenges will be overcome, but for top companies with loads of competitors, patent diving yields a spotlight on potential solutions. Read More...

A possible upside of artificial light

Is artificial light really able to replace my coffee? Nah. Read More...

LED features single photon emission

Researchers have created an all-electrical quantum LED with single-photon emission that is atomically thin and has potential as an on-chip photon source for quantum information apps. Read More...

People not immune to health impact of LEDs, according to the AMA

The American Medical Association has warned that high-intensity LED streetlights that emit blue light can disturb our sleep rhythms and health. Read More...

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LED strings driven by current source/mirror

This unusual dual-output current source can, for example, drive LED strings at any desired current ratio. Read More...

LED current regulator has low dropout

Meet an interesting addition to the field of LED current regulators. Read More...

HB-LED flashing beacon repurposes switching regulator

A classic, low-cost “switcher” IC is repurposed to flash a high-brightness LED in this minimal-parts-count Design Idea. Read More...

Two PIC pins drive six LEDs

Here’s a take on LED multiplexing with minimal output pins. Read More...

Failsafe multichip LED module driver

Keep a power LED module with multiple strings operating despite fault conditions. Read More...

Design Notes: 60V, Synchronous Step-Down High Current LED Driver

Highly efficient high-power LED controller/driver also facilitates MPPT. Read More...

H-bridge paves new ways for LED lighting

Drive a LED array directly from the AC mains in full-wave current-limited mode to realize a flicker-free, energy-efficient solid-state lamp. Read More...

Pocket white-LED torch is power efficient

This single white-LED torch can be housed in an empty glue-stick tube and has a long rechargeable-battery life. Read More...

An improved offline driver lights an LED string

Keep the current constant and the voltage low for improved power efficiency. Read More...

Photo meter assesses ambient light

When most PN-junction diodes are reverse biased, they will produce a small photovoltaic output as the light level is increased. Read More...

Use an LED matrix horizontally

Using one 5×7 LED matrix horizontally instead of vertically allows the display of two characters instead of one. Read More...

Eight LEDs make a 100-division voltmeter

Use a counter IC to drive two sets of four LEDs. Read More...

An LED's intrinsic capacitance works in a 650-mV LRC circuit

The LED and a discrete inductor form an LC tank circuit. Read More...

LEDs indicate sound level

Build a battery-operated portable meter to measure sound-pressure levels. Read More...

Driver circuit lights architectural and interior LEDs

Hold the current constant and within tolerance. Read More...

LED-current limiter accepts ac or dc

Prevent excessive current from overdriving your LEDs. Read More...

Protect power-LED strings from overcurrent

Add diodes and a transistor to a current mirror to prevent LED damage. Read More...

Efficient LED power supply has battery backup

Power three to six LEDs from an ac- or dc-power source and charge a backup battery. Read More...

High-power LED drivers require no external switches

Suiting a variety of applications, these circuits transform a switching regulator into a current source for driving power LEDs. Read More...

Line-powered driver lights up high-power LEDs

LED array reduces power and maintenance expenses. Read More...

Linear and switcher LED supplies combine, overcome disadvantages of each topology

Linear and switcher LED supplies combine to overcome disadvantages of each topology. Read More...

Readers' Choice: Vote for your favorite Design Ideas

Community driven, Design Ideas have always resonated deeply with EDN’s audience, with their inspired, hands-on, practical, and useful circuit-design contributions. Vote for the ‘best of the best’ here. Read More...

Adjust power-efficient LED switch to any light intensity

Drawing only microamps (other than load current), this circuit switches in accordance with ambient light levels. Read More...

LED bar-graph display represents two digits

Novel circuit uses a reference ladder signal based on the most-significant-digit display. Read More...

Arrange LEDs as seven-segment displays

If you have a pin-limited PIC microcontroller, you can still produce a seven-segment display. Read More...

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Lighting manager offers spectral tuning

A smart-lighting manager, the AS7221 from ams is a network-enabled device that provides CCT tuning for white LED smart lighting. Read More...

LED driver handles 100 W

Thomas Research Products’ LED100WPS1-24 constant-voltage driver can be used in both indoor and outdoor commercial and industrial applications. Read More...

Broadband IR LED enables food analysis

Osram’s SFH4735 LED emits broadband IR light over a wavelength range of 650 nm to 1050 nm to serve as a light source for near-IR spectroscopy. Read More...

Multichip LEDs suit entry-level ADB headlights

Osram’s Oslon Black Flat S series of surface-mount LEDs comprises configurations containing up to five individually controlled chips. Read More...

LED driver furnishes up to 40 W

A hysteresis-mode DC/DC step-down converter, the AL8860 from Diodes Inc. drives single or multiple series-connected LEDs. Read More...

LED driver fits small screens

A current-mode boost LED driver, Diodes’ AL3050 packs a 30-V MOSFET and Schottky diode to enable it to drive up to eight LEDs in series. Read More...

Control device simplifies LED dimming

Inspired LED’s Triac Analyzer allows low-voltage LED systems to be controlled using almost any standard triac wall dimmer. Read More...

Lighting system brightens enclosures

Rittal offers the SZ 2500 series of LED system lights to illuminate every corner of an industrial enclosure, from ceiling to floor. Read More...

Multi-die LEDs simplify optical design

Luxeon 5050 LEDs from Lumileds are housed in a multi-die package with a round light emitting surface that is just 4.6 mm. Read More...

Step-up converter drives LED strings

A monolithic synchronous step-up DC/DC converter, the LT3922 from Linear Technology, packs 40-V, 2-A power switches and a PWM generator. Read More...

Side-view LEDs enhance gaming experience

Cree’s QLS6A and QLS6B bright side-view LEDs deliver up to 66% higher luminous intensity than other side-view LEDs. Read More...

LED floodlights meet diverse market needs

Eaton has expanded its Lumark Night Falcon LED floodlight series with large and small models to replace HID lamps rated from 70 W to 1000 W. Read More...

LEDs brighten food display cases

Lumileds now offers its Luxeon Stylist Series COB LEDs with FreshFocus technology to showcase breads and pastries in an appetizing light. Read More...

Rugged indicators employ recessed LEDs

Front panel-mount diffused LED indicators in the L65 series from VCC snap into a 0.315-in. (8.0-mm) panel hole without additional hardware. Read More...

ICs drive up to 192 LEDs

ISSI’s IS31FL3733, IS31FL3736, and IS31FL3737 driver ICs handle LED matrices comprising 192, 96, and 144 LEDs, respectively. Read More...

High-power LEDs lower system costs

Optimized to simplify directional and semi-directional LED system designs, the XLamp MHB-B series from Cree delivers up to 931 lumens at 85°C. Read More...

HID LEDs deliver up to 20,000 lumens

Lunera’s third-generation of HID LED lamps includes one of the first line-driven 20,000-lumen HID LEDs to replace 400-W MH and HPS lamps. Read More...

Mid-power UV LED operates at 365 nm

A ceramic-based UV LED, the VLMU1610-365-135 from Vishay provides typical radiant power of 18 mW at 20 mA and 50 mW at 60 mA. Read More...

Energy-efficient LED lamp replaces HID lamps

Lunera’s HID LED 360 lamp for architectural post-top fixtures replaces MH and HPS HID lamps, while lowering energy and maintenance costs. Read More...

Display driver shield speeds prototyping

The MAXREFDES99# Arduino and mbed-compatible reference design from Maxim enables the creation of 16×16 LED arrays for signage applications. Read More...

LED driver suits buck topologies

LYTSwitch-1 from Power Integrations is a family of single-stage, nonisolated buck LED drivers that ensures high power factor and low THD. Read More...

Backlighting kit offers trimmable panels

Lumitex offers the Cut-2-Size backlighting kit for easy prototyping of membrane switches, keypads, overlays, LCDs, and other graphic displays. Read More...

Latching connectors secure LED fixtures

Phoenix Contact has expanded its PTSM line of miniature connectors with versions that lock together for use in LED lighting applications. Read More...

LED canopy shines bright at 143 lumens per watt

An LED canopy and soffit luminaire from Cree, the CPY-20L produces 20,784 lumen with an efficacy of up to 143 lumens per watt at 5700K. Read More...

LED headlight connector mates securely

The single-row, wire-to-board MiniBridge Koshiri connector from ERNI improves mating integrity in intelligent LED headlight systems. Read More...

Buck-boost LED driver supplies over 100 W

Using four external N-channel MOSFETs, the LT8391 synchronous buck-boost DC/DC controller from Linear Technology drives a wide range of LEDs. Read More...

Supplies power commercial and industrial lighting

The first member in LinkCom’s Incore family of constant-current LED power supplies is the slender, low-profile 45-W DBFN line. Read More...

LED controllers are digitally enhanced

Two analog power controllers from Microchip, the MCP19116 and MCP19117 enable intelligent, configurable, and accurate LED lighting. Read More...

LED control module offers touch dimming

A touch-operated dimming control module for constant-voltage indoor LED lighting, the PDA-DIM10A from Phihong delivers 10 A of output current. Read More...

Retrofit conversion kit promotes LED lighting

Lunera’s Susan Lamp E26 LED kit converts existing metal-halide or high-pressure sodium fixtures into energy-efficient HID LED lights. Read More...

LED drivers enable efficient TRIAC dimming

Power Integrations’ LYTSwitch-3 single-stage LED driver ICs provide power factor correction and constant-current output for TRIAC dimming. Read More...

Bright PAR30 LED bulbs produce 850 lumens

Cree’s TW series of PAR30 LED bulbs delivers bright focused light to provide better lit spaces for both homeowners and retailers. Read More...

Switching regulators drive automotive LEDs

The A6216 switching regulator from Allegro MicroSystems provides constant-current 2-A output and internally generated PWM dimming capability. Read More...

LED module teams with off-the-shelf quadruple lenses

Based on a metal-core PCB, Vishay’s VLSL12A03-3Q3T-50A comprises 12 cool white LEDs with a luminous flux of 4000 lm each at 1 A. Read More...

LED dimmer simplifies matrix designs

An LED bypass switching device, the LT3965 from Linear Technology, enables independent dimming of eight individual LEDs or LED segments. Read More...

LED intensifies projection lighting

Osram’s Ostar Projection Power LED enables projectors with luminous intensities of 2500 to 3500 lumen to be equipped solely with LED lighting. Read More...

Platform simplifies digital control of power supplies for LED lighting

Digitally-configurable power controllers offer smooth LED dimming, high PFC, and low solution cost. Read More...

High-intensity color LEDs claim industry's highest candela performance

Cree's XLamp XQ-E series offers white and color LEDs with high performance and small size. Read More...

Supplies deliver constant current to LEDs

Comprising eight models, the LDC-185 series of AC/DC LED drivers from MicroPower Direct produces a constant-current output of 0.50 A to 5.25 A. Read More...

MCU dev kit secures your connection to the cloud

TI’s TM4C MCU family and low-cost LaunchPad development kit with hardware-encryption security features provide a secure cloud connection. Read More...

LED drivers ensure flicker-free dimming for white and color-mixing LED bulbs

Diodes Inc's DC to constant current LED driver ICs offer a cost-effective solution that enables accurate color mixing and flicker-free dimming. Read More...

IoT platform brings distributed intelligence to smart lighting and applications

WiSilica's WiSe Connect IoT platform integrates a suite of intelligent lighting control functions into a platform that can be tailored to meet the building automation needs of nearly any residential, commercial, or industrial application. Read More...

Harmonic analyzer provides power waveform measurements

Vitrek’s PA900 Precision Power Analyser is positioned as the first of a new class of affordable graphical power analyzers. Read More...

Innovative 8-bit PIC MCU family is tailored for demanding Smart Lighting applications

Microchip has introduced two new families of genuinely innovative 8-bit PIC MCUs, including one specifically designed for Smart Lighting and motor control applications. These minimalist machines are designed to meet the tight cost constraints of IoT applications with elegant architectures which can squeeze out the greatest possible functionality from the smallest possible number of transistors, miliwatts and pins. Read More...

Smart, low-cost daylight harvesting enabled by multi-sensor controller

Deep Roof Lighting as come up with an inexpensive and highly-effective daylight harvesting system that's easy to install in a variety of configurations. Priced at under $200, it can control mixed groups of 30 or more LED, incandescent, and fluorescent fixtures – even if they require different control interfaces. Read More...

Surface-mount LED chip array offers lower solution costs, higher light quality

Aimed at reducing assembly and optic design costs of retrofit bulbs and lighting equipment, Osram Opto Semiconductors' Duris S 10 Chip Array SMD (CAS) boasts high efficiency, high light output and uniform color appearance. The LED’s compact 7.7mm light-emitting surface enables compact optics with beam angles as narrow as 120° and helps simplify the integration of lenses, reflectors and other standard accessories. Read More...

$49 Arduino-compatible board features enhanced Cortex M7 MCU

STMicro's Arduino-compatible STM32F7 Discovery Kit is an exciting development for DIY-ers interested in IoT applications. Read More...

Wood-fired LED lantern converts waste heat into light & power

Don't let the Stove Lite LED lantern's appearance deceive you. Beneath those old-timey looks, lies a modern thermo-electric generator (TEG), which uses the Seebeck effect to convert the heat of your wood stove into enough energy to run its LED lamp. This rugged wood-powered wonder also doubles as a battery charger for your phone or other mobile device. Read More...

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Teardown: What killed this LED bulb?

A failed 60W-equivalent A19 LED light bulb provided an intriguing teardown opportunity, but what caused the failure? Read More...

Teardown: LED touch controllers & PSU

Look inside some low-cost LED touch controllers. Read More...

Teardown: Motion-sensing LED lighting

An AC power source and motion-sensor activation combine to create some notable design differences between this LED light and its battery-powered, touch-operated Enbrighten sibling. Read More...

Teardown: Cool LED lighting

How does Jasco's Enbrighten battery-powered guide light deliver on its coverage and temperature claims? Find out in this teardown. Read More...

What's inside the Samsung 40W-replacement-LED light?

What's inside the Samsung 40W-replacement-LED light? Read More...

Remote phosphor expands reach of LED light

This Prying Eyes explores how an LED bulb is able to project light in an almost 360-degree pattern. Read More...

Visionaire Lighting’s Solar Vision Pole: shedding light on off-grid lampposts

Certain applications justify paying a premium for high efficiency, long life, ruggedness, and light-color-temperature control, and these applications represent the sweet spot for HB LEDs (high-brightness light-emitting diodes). Read More...

Compact fluorescent lights: Not always the best solution

Prying Eyes: A look inside a CFL bulb helps explain why they're no good in downward-facing installations. Read More...

Way, way off the grid: Powering the Phoenix Mars lander

Prying Eyes: An inside look at the power-generation, -regulation, and -delivery system for the Phoenix Mars lander. Read More...

LED lighting teardowns: Five lighting designs that illuminate the future of lighting

Early SSL products are making their way onto store shelves and into inventory. These products can indicate what direction SSL design will take, at least in its early stages. Read More...

Tear-down: inside a 7W LED light bulb

A 5000K version of a 7W LED bulb served as the sacrificial lamb to see what's inside. Read More...

LED bulbs reveal different design approaches

A peek into the Philips LED bulb’s electronics and the 6W, dimmable Pharox 300 contrasts two approaches in how a bulb handles the protection of the LED-power-control electronics. Read More...

Teardown: LED light shrinks size, cost with non-isolated driver

What has changed in LED bulb design to allow the steep drop in prices that is happening? Tearing apart a LED bulb provides a look at some of the design trends in LED lighting. Read More...

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Measurement basics in LED thermal management

It takes more than the ability to read a datasheet to figure out the thermal aspects necessary for your LED design—here’s some help. Read More...

The DB-100 controller: A breakthrough in simplifying LED control

The DB-100 controller will simplify high-CRI, dimmable, variable-color-temperature LED control. Read More...

LEDs will inherit the world

In 60 years, all lighting functions will be handled by LEDs, and it will be a substitute for Wi-Fi. Read More...

What you don’t know about LED light intensity curves for grow light apps

We know a lot about how light intensity curves work—but you may not know about the concept described in this article. Read More...

Basic flashlamp illumination circuitry for cellular telephones and cameras

The LT1618 is an ideal IC for providing constant current to Lumileds white LEDs from a variety of power sources. Read More...

Monolithic converter drives high-power LEDs

LED drivers must regulate a constant LED current, regardless of input and output voltages. Now a single switching regulator with the ability to be configured in a variety of topologies for high power constant LED current is available. Read More...

LEDs go everywhere

It has been a long time coming, but the cost structures normally associated with LED equivalents have dropped dramatically over the past 5 years or so, and the future is bright for LED bulbs. Read More...

LED lighting: More intelligent, more beautiful, more affordable

The LED industry's products will become more efficient, reliable, and, one can hope, interoperable in the near future. But underlying all these advances will be the relentless pressure to deliver LEDs at lower price points. Read More...

Addressing design issues when working with UVC LEDs

With careful consideration, UVC LEDs can decrease footprint and power consumption, improving cost of ownership for the end user. Read More...

Wide input range 1A LED driver powers high brightness LEDs with automotive and 12VAC supplies

The LT3474 LED driver allows today’s ultrabright LEDs to far exceed the performance of incandescent bulbs in both efficiency and lifetime. Read More...

High voltage buck converters drive high-power LEDs

The LT3474 and LT3475 LED drivers have onboard high voltage NPN power switches and internal sense resistors to minimize board space, reduce component count and simplify design. Read More...

Versatile high power LED driver controller simplifies design

Until recently, driving large arrays of individual LEDs stacked in series usually required an inefficient linear regulator scheme or a more complicated multiple IC switching regulator configuration. Now, there is a single-IC solution which offers low parts count, high efficiency, and supports several operating modes. Read More...

Open standards drive smart lighting and the Enterprise IoT

Open standard-based wireless lighting control systems are a catalyst ushering building controls into the Enterprise Internet of Things (E-IoT). Read More...

Tiny universal LED driver can gradate, blink, or turn on nine individual LEDs

As device designers strive to differentiate their products on the shelf, the number and complexity of lighting effects grows. In this chapter of Analog Circuit Design, we'll see how the LTC3219 9-output universal LED driver can be programmed to individually gradate, blink, or turn on nine individual LEDs using nine 6-bit DAC-controlled LED current sources. Read More...

Versatile TFT LCD bias supply and white LED driver in a 4×4mm QFN

Power supply designers for displays in industrial and consumer devices must contend with shrinking board area, tight schedules, and variations in display types and feature requirements. The LTC3524 simplifies the designer’s job by combining a versatile, easily programmed, TFT LCD bias supply and white LED backlight driver in a low profile 4×4mm QFN package. Read More...

μModule LED driver integrates all circuitry in a SMT package

Despite the clear advantages LEDs offer, their requirement for regulated voltage and current make LED driver circuits more complex than the venerable light bulb, but some new devices are closing the gap. Read More...

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Studying the green gap in LED efficiency

Within the green LED spectral range, efficiency deteriorates based on diminishing electron-hole wave function overlap when compared with blue LEDs. Read More...

Details emerge on OLED TVs at CES

As TVs grow paper thin, they require ever-greater energy efficiency, which is the hallmark of OLED technology. Read More...

Why are these LED aisle lights being pulsed?

After snapping a photo of the LEDs lining the edges of a movie theater aisle, this engineer wondered why the lights were being pulsed. Read More...

Clean water courtesy of LEDs

Metal foil-based LEDs being researched at Ohio State University could provide portable sterilization equipment for clean drinking water. Read More...

Cree calls out counterfeit LEDs in patent infringement suit

Cree has filed a patent infringement suit against a distributor of a flashlight that it says uses counterfeit LEDs. Read More...

LED lamp cycles on and off, why?

When an LED flood lamp started cycling, I suspected temperature. Now, how can we find what's the root cause? Read More...

The largest LED video display in all of sports

The largest LED video display in sports, engineered by Daktronics, will be housed at the new Mercedes-Benz Stadium, opening next year. Read More...

Medicinal cannabis improves under LED lighting

Here’s interesting information regarding a study of medicinal cannabis and how it does under LED lighting. Read More...

Patent diving: Apple’s OLED plans

Sometimes it’s hard to get a pulse on how certain technical challenges will be overcome, but for top companies with loads of competitors, patent diving yields a spotlight on potential solutions. Read More...

A possible upside of artificial light

Is artificial light really able to replace my coffee? Nah. Read More...

LED features single photon emission

Researchers have created an all-electrical quantum LED with single-photon emission that is atomically thin and has potential as an on-chip photon source for quantum information apps. Read More...

People not immune to health impact of LEDs, according to the AMA

The American Medical Association has warned that high-intensity LED streetlights that emit blue light can disturb our sleep rhythms and health. Read More...

LED bulbs can bring heat

When the base of an LED bulb seems hot to the touch, some testing is in order. Read More...

LED driver ICs cut low-frequency flicker

There’s an age-old flicker problem with LEDs, but it’s finally really going away, thanks in part to Infineon’s XDPL8220 driver IC. Read More...

Insect and bird behavior is influenced by LED lights

Study results have been on the rise that indicate an impact on insect and bird populations from the installation of LEDs over traditional streetlamp lighting. Read More...

LEDs will overtake ballast segment

LED lighting ballast shipments are expected to increase 30% by 2023. A new research report explains why. Read More...

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