Integrating a low voltage 3V MCU EFM8 from Silicon Labs to 5 volt sytem. Link here (PDF)
When using a 3 V device in a 5 V system, the user must consider:
• A 3 V power supply must be provided.
• A 5 V device driving a 3 V input.
• A 3 V device driving a 5 V input.
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.
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.
Brief app note from OSRAM, LEDs for heart rate monitoring through skin reflection of emitted light. Link here (PDF)
This application note provides a short introduction into the general use of LEDs for wearable applications, with a focus on heart rate monitoring.
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.
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.