App note: High-speed lithium-ion battery charger

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C8051F300 implementation of Li-Ion battery charger from Silicon Labs. Link here (PDF)

Driven by the need for untethered mobility and ease of use, many systems rely on rechargeable batteries as their primary power source. The battery charger is typically implemented using a fixedfunction IC to control the charging current/voltage profile.

The C8051F300 family provides a flexible alternative to fixed-function linear battery chargers. This note discusses how to use the C8051F300 device in Li-Ion battery charger applications. The Li-Ion charging algorithms can be easily adapted to other battery chemistries.

App note: Preventing LED failures caused by corrosive material

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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 fulfill a wide range of customer needs and requirements in indoor and outdoor applications.

This application note provides information about the chemical compatibility of certain substances with LEDs, particularly with regard to some of their basic components. In this context, the main mechanisms of chemical incompatibility are illustrated using examples of blue and white LEDs.

App note: Fundamentals of operation and recent developments of class D amplifiers

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Good read about class D amplfiers from MAXIM Integrated. Link here (PDF)

A Class D amplifier’s high efficiency makes it ideal for portable and compact high-power applications. Traditional Class D amplifiers require an external lowpass filter to extract the audio signal from the pulse-width-modulated (PWM) output waveform. Many modern Class D amplifiers, however, utilize advanced modulation techniques that, in various applications, both eliminate the need for external filtering and reduce electromagnetic interference (EMI). Eliminating external filters not only reduces board-space requirements, but can also significantly reduce the cost of many portable/compact systems.

App note: Avoid overvoltage stresses by minimizing power supply pumping on single-ended output, class D audio amplifiers

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Here’s class D audio amplifier pumping remedy from MAXIM Integrated, power-supply pumping is a problem that occurs when playing low-frequency audio signals through a single-ended output. Link here (PDF)

This application note explains what power-supply pumping is and how it occurs in designs that employ a Class D audio amplifier with single-ended output loads. The article presents three design solutions that will reduce the problem. Mathematical equations show that use of power-supply capacitors greater than 1000µF greatly reduce the phenomenon.

App note: Performance of echo canceller of LC823450

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Audio application echo canceller LC823450 from ON Semiconductor. Link here (PDF)

This application note describes the performance of Echo canceller of LC823450 Series. The customer can improve the sound quality of hands free communication by using this canceller. Its function can be used for various products such as Wireless headset. Earbads or other voice communication products.

App note: Enable pin operation and functions of eFuses

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Get to know a number of useful usage of the enable pin of ON Semiconductor’s eFuse. Link here (PDF)

ON Semiconductor electronic fuses (eFuses) are analog integrated circuits that are used to protect circuits operating from 3.3, 5, or 12 V DC supplies. They have numerous protection functionalities such as overvoltage clamping, current limiting, thermal shutdown, and a controlled output voltage slew rate. They are available in thermal latching or thermal auto-retry configurations.

A key feature of the eFuse family is the enable pin. This application note describes the features of the enable pin and provides guidance to ensure its proper use. The enable pin of any eFuse may be left floating if the application does not require that it be controlled and does not require thermal fault notification.

App note: eFuse load current measurement

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App note from ON Semiconductor on eFuse current measurement. Link here (PDF)

This application note describes the load current measurement solution for the eFuses which do not provide load current monitoring feature. Since almost all of the eFuses provide adjustable current limit functionality by utilizing an external current limiting resistor between “ILIM” and “SRC” pins, it is possible to connect a current sense amplifier across that resistor and measure the voltage drop across it which would be proportional to the load current. This method mainly requires a current sense amplifier and allows user to measure the system load current without introducing any additional resistance in series with the load path.