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 in appliances and other equipment leverage MCUs and several integrated circuits to enable functions, such as sensing, process control and user interface (UI).
The user interface consists of input controls, visual and audio feedback used to configure the product to perform complex tasks. An aesthetically pleasing UI is a major differentiating feature for home appliances such as ovens, washing machines and refrigerators. Home appliance UIs commonly use capacitive or inductive touch sensing to provide an easy to clean interface unmatched by mechanical buttons. In addition to touch sensing, a UI has to provide audio and visual feedback in response to the user selection. The UI may not be the most important factor in determining the commercial success of CE devices. However, once parity is established on the major functions such as washing capacity, energy efficiency, etc, the UI becomes a key differentiator. Today, parity has been established on most of the important factors making the UI a product differentiating factor.
As the trend continues to move away from purely mechanical switches to a fully electronic interface expect to see demand for LEDs and drivers to continue increasing.
App note from ON Semiconductor about eFuse or Electronic fuse. Link here (PDF)
The primary function of an Electronic Fuse, or eFuse, is to limit current, the same function provided by any fuse or positive temperature coefficient device (PTC). An eFuse, however, provides this function with much more versatility than either of these devices. An eFuse, unlike a standard fuse, need not be replaced after it functions and eFuses also respond more rapidly than a either a fuse or PTC. eFuses can also limit current in situations in which a traditional fuses and PTCs will not work. This is especially true when voltage is first provided to a circuit, such as during a hot plug operation, when inrush current can be extremely high. This application note will explain the basic operation of an eFuse’s current limit function and explain important eFuse concepts such as Overload and Short Circuit currents, and Kelvin versus Direct connection of the eFuse’s current sense resistor.
App note discussing extended features of NCP12600, NCP12600 is a multi-mode controller for offline power supplies by ON Semiconductor. Link here (PDF)
Beside the novel multi−mode structure it embarks, the NCP12600 packs a lot of features such as an efficient short−circuit protection architecture, a start−up sequence with a slow switching frequency ramp−up, a fast reset when latched and an auto−recovery scheme when line cycle dropout occurs in latched versions. Let’s discover these novelties in the present application note.
LEDs used in a controlled environment greenhouse farms, an app note from Würth Elektronik. Link here (PDF)
Greenhouse farms may not be a new technology but with an every growing world population and the move towards sustainability, intensive yet highly efficient and standardized food production will increasingly become the norm in future years opening a potentially huge new agricultural sector that incorporates the latest technologies from the bioscience and engineering fields. But how can researchers and personnel from these separate fields understand the mutually dependent requirements of indoor greenhouses? Photosynthesis is the process that converts water and carbon dioxide into complex carbohydrates (i.e. sugars) and oxygen using energy from light. However, although the energy radiated by the sun that reaches the earth’s surface consists of the entire spectrum of visible light (and more), plants only utilize specific frequencies of light for photosynthesis. These frequencies are related to the absorption characteristics of different pigments that are present within organelles called chloroplasts that are responsible for different functions of photosynthesis.
Light emitting diodes are solid-state, light generating components that, have become and will continue to be one of the greatest drivers in the expansion of internal greenhouses due to their advantages over incandescent bulbs, fluorescent bulbs, high-pressure sodium lamps and mercury lamps. Their main advantage stems from their ability to generate specific wavelengths of light. To meet the requirements for Horticultural LED’s for Indoor-farming, Würth Elektronik offers the WL-SMDC SMD Mono-color Ceramic LED Waterclear series of LEDs. The WL-SMDC range has been expanded to include wavelengths of 450 nm (Deep Blue), 660 nm (Hyper Red) and 730 nm (Far Red), which have been selected to match the absorption spectra of photosynthetic pigments. In addition to the existing products in the range, a diverse range of combinations is possible that can be catered to the target cultivar.
Application note form Würth Elektronik about EM radiation radiated from inductors in DC-DC converters. Link here (PDF)
This Application Note focuses on the Electro-Magnetic (EM) radiation behavior of power inductor(s) in DC-DC converters, which is dependent on several parameters such as ripple current, switching frequency, rise & fall time of a switching device, the core material and its permeability and suggests several design tips to mitigate these EMI effects.
App note from TT Electronics about infrared diode specs, how they vary from different manufacturers, and help clear things about infrared definition of parameters. Link here (PDF)
Infrared emitting diode power measurement is dependent upon a number of variables which must be precisely defined in order for design engineers to utilize data sheet information. Manufacturers differ not only in the techniques used in measuring power, but also in their interpretations of the definitions of the parameters which are measured. This application bulletin is intended to clarify this misunderstanding, especially for GaAs and GaAlAs solution grown epitaxial devices.
Application notes from TT Electronics on optical encoders versatile sensing. Link here (PDF)
Linear and rotary encoders have come in a wide variety of design styles over the years, the most common being rotary switches, potentiometers, capacitive, magnetic, and optical types. The optical encoder has become the most popular of these encoding methods due to its long life, simplicity of construction, versatility, high accuracy and high resolution. This application bulletin will briefly define an optical encoder, and bring the designer up to date on encoder terminology, design techniques and limitations.
Inrush current evaluation from Aimtec. Link here
In AC/DC power converters beyond a few watts, during the initial application of power an excessive inrush current will flow when the input capacitors are suddenly charged. If unhindered the inrush current can easily exceed 50 A at the peak of the AC cycle and severely stress the converter’s fuse and input rectifiers, thereby significantly reducing the reliability and life expectancy of the modules. Universal power supplies (supplies which accept a wide range of input voltages) are particularly susceptible to high inrush current since their input capacitors must be large enough to handle line voltages as low as 110 VAC, as well as voltages as high as 305 VAC at start-up. In these environments, a power-supply failure or a tripped circuit breaker can be inconvenient at best, and expensive or dangerous at worst.
App note from Aimtec on dimming LEDs. Link here
With the phenomenal growth of the LED lighting market, there has been a natural growth in demand for highly efficient and controlled LED drivers. Applications from ‘smart’ street lights, flashlights, digital signage and many others require not only highly regulated currents, but in many cases dimming capability in order to sustain the energy efficient scheme and end use flexibility behind LED design.
As there are several ways to achieve dimming of an LED, we describe here the main methods that are used to provide dimming for LED’s from a switch mode LED driver.
Save PCB space by utilizing EEPROM SOIC-8 area, here’s an application note from Microchip. Link here (PDF)
For many years, the 8-lead SOIC package has been the most popular package for serial EEPROMs, but now smaller packages are becoming more commonplace. This offers a number of benefits; the reductions in footprint size and component height are some of the more obvious ones. Smaller packages also generally offer a cost advantage over their larger counterparts.