App note: Comparison of LED circuits

Another application note from OSRAM on different LED circuit design failure mode. Link here (PDF) In recent years, Light Emitting Diodes (LEDs) have become a viable alternative to conventional light sources. The overriding advantages long life, high efficiency, small size and short reaction time have lead to the displacement, in ever increasing numbers, of incandescent […]

App note: Dimming LEDs with respect to grouping current

App note from OSRAM describing the behaviour of LEDs in respect to brightness by varying the current and to suggest solutions for avoiding negative influence for the application. Link here (PDF) In the design of a driving circuit for LEDs, the dimming behaviour is an important topic to fulfill the end customer requirements. The behaviour […]

App note: Digital potentiometer (POT) to control LED brightness

Controlling LED brightness through digital potentiometer and a LED driver from ON Semiconductor. Link here (PDF) Light-emitting diodes (LEDs) require a regulated current, and their brightness is proportional to the current that flows through them. Some LED drivers use an external resistor to set the LED current. A digital POT can replace a discrete resistor […]

App note: Thermal consideration of flash LEDs

Pulsed LED application like flash LEDs requires adequate thermal management to counter the heavy heat caused by larger current, here’s an app note from OSRAM discussing on thermal management of LEDs. Link here (PDF) This application note focuses on how to develop an adequate thermal management for LEDs in camera flash applications. It provides information […]

App note: Dimming InGaN LEDs

App note from OSRAM on InGaN LEDs dimming method without penalty on its wavelength. Link here (PDF) While the InGaN technology produces the brightest light output across Blue, Deep blue, Verde, True green and White, it is important to understand that the wavelength of the light emitted depends on the forward current. In order to […]

App note: Driving LEDs with a PIC Microcontroller

An App note from OSRAM on an Intelligent control circuitry example using a PIC Microcontroller. Link here (PDF) Nowadays, applications increasingly make use of LEDs as a replacement for traditional light bulbs. For example, LEDs are frequently used in the design of automobile tail lights, signal lights, traffic signals, and variable message signs. LEDs provide […]

App note: Package-related thermal resistance of LEDs

App note from OSRAM on thermal resistance for LEDs and IREDs (IR emitting diodes). Link here (PDF) In order to achieve the expected reliability, lifetime and optimal performance of LEDs, especially for high-power LEDs, appropriate thermal management is of the utmost importance. One of the key parameters for good thermal management is the temperature of […]

App note: Pulsed Over-Current Driving of LEDs

App note from CREE on driving LEDs over its specified current capability. Link here (PDF) The Applications Engineering team at Cree is often asked whether it is safe to operate Cree XLamp® LEDs with pulsed currents above the maximum data-sheet rating. This question is usually asked in the context of legitimate product requirements such as […]

App note: Avoidance of ceramic-substrate-based LED chip cracking induced by PCB bending or flexing

Application note from CREE on the causes of ceramic-substrate-based failures due to PCB board stresses and how to minimize their occurrence. Link here (PDF) Printed circuit board (PCB) bending and/or flexing is an unavoidable phenomenon that is known to exist and is easily encountered during electronic board assembly processes. PCB bending and/or flexing is the […]

App note: Preventing LED failures caused by corrosive material

Chemical compatibility of LEDs application note from OSRAM. Link here (PDF) The performance and stability of light emitting diodes (LEDs) may be influenced by various chemical incompatibilities arising from chemicals and materials used, amongst other things, in luminaire construction, or by gases in the proximate environment of LEDs during field operation. Nevertheless, LEDs have to […]

App note: Advanced LED rework procedure for video wall and signage applications

App note from OSRAM about LED rework on signages and their demand for more sophosticated tools. Link here (PDF) SMT LEDs have became more and more popular in video wall and signage applications, replacing radial LEDs. This leads to more difficulties during the repair or replacement of failed LEDs on PCBs, especially for QFN (Quad […]

App note: Matrix LED and where they are used

White paper about matrix LED usage from Integrated Silicon Solution Inc. (ISSI). Link here (PDF) People today come in contact with a wide range of consumer electronics (CE) devices in their daily lives. CE devices have become increasingly complex with added functionality enabled by MCU’s which provide the intelligence for automating functions. Control panels used […]

App note: 12Vac LED Driving without smoothing capacitors

Application note from Diodes Incorporated on driving 12Vac LED without smoothing capacitors with their Zetex ZXLD1360 LED driver IC and SBR2A40P1 super barrier rectifier. Link here (PDF) LED based architectural lighting is now coming of age, but there are still some problems to be considered when designing luminaires to be fitted into existing installations. This […]

App note: How to measure thermal resistance of LED emitters and LED arrays

Another white paper from Lumileds about LED thermal resistance. Link here (PDF) Thermal performance is the most critical factor of a well-designed LED lighting system. A lighting system with proper thermal design has higher efficacy, meaning more light can be extracted using less energy, and better long term reliability.

App note: Flash for “Selfies”

Effective front facing camera flash discussed in this white paper from Lumileds. Link here (PDF) Smartphones are ubiquitous in everybody’s daily lives, a trend that shows no sign of slowing. A key component of the smartphone is the camera, which has gained market share over Digital Still Cameras due to its convenience. As the demand […]

Comfort Thermometer display built with 517 individual LEDs

Richard wrote in to tell us about a ‘Comfort Thermometer display built with 517 LEDs’ that he has just finished building: Comfort Thermometer Display built with 517 individual LEDs and the following microprocessors: 1) PiC24FV16KA301 – controlling outer 36 RGB LEDs 2) PIC16F886 – bargraph and pink LEDs animations 3) ATmega328 – controlling 7-segment display […]