App note: Using Cymbet™ EnerChip™ batteries instead of coin cells and super capacitors

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High charge/discharge cycle and solid state reliability EnerChip from Cymbet make this a good replacement for super caps and coin cell backup batteries. Link here (PDF)

Primary and secondary (i.e., rechargeable) coin cell batteries, as well as super capacitors, have been in use for years as auxiliary power sources for applications including SRAM, real-time clocks, and microcontrollers. Now, a new type of rechargeable battery is available from Cymbet Corporation, the leader in thin film rechargeable micro-batteries.

App note: Battery fuel gauge IC (LC709203F) for 1-Cell Lithium-ion (Li+)

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Lithium-ion fuel gauge IC from ON Semiconductors. Link here (PDF)

The LC709203F is an IC that measures the remaining power level of 1-cell lithium-ion (Li+) batteries used for portable
equipment etc.
This product reduces fuel gauge errors with a unique correction technology during measurement of battery temperature and
voltage.
This technology has inherently high precision without the need for an external sense.

App note: Snubber capacitors for complete insurance of power semiconductors

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An application note from WIMA about snubber capacitors, Link here.

The trend of modern semiconductor technology towards increasingly powerful applications results in the fact that switched currents and voltage levels are continuously increased and that simultaneously the switching speed is also increasing markedly.
The developments in the area of power semiconductors include the component group IGBT (Insulated Gate Bipolar Transistor) or IGBT modules.
The switching capacity with shortest switching times which can be realized using IGBTs necessitates an extremely low-inductance circuit design. Even the low self-inductance of the power bus may induce dangerous voltage overshoots between collector and emitter which may result in the destruction of the valuable power semiconductors.
To protect the components, so-called snubber suppressor circuits are used. The most important component in this respect is a low-inductance pulse capacitor in order to attenuate or cut off peak voltages.

App note: Selection of capacitors for pulse applications

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Guidelines from WIMA about selecting capactiors for pulsed conditions. Link here

The maximum permissible AC voltage that can be applied to capacitors in sinusoidal waveform applications, can be determined from the graphs in the respective capacitor ranges.
However, where pulse conditions exists, the following procedure is to be observed to ensure that the correct capacitor rating is selected for a particular duty:
– Rated voltage
– Maximum current
– Dissipation
– Determining the permissible AC voltage and AC current at given frequencies

App note: Measuring a loudspeaker impedance profile using the AD5933

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An application note from Analog Devices about AD5933, this provides a low cost substitute to expensive test equipment like signal generators, oscilloscope and voltmeters in getting the speaker’s impedance profile. Link here (PDF)

This application note describes a circuit architecture using the AD5933 that allows the system designer to measure the impedance profile of the loudspeaker and integrate this circuitry into the audio signal chain. This offers many benefits. Upon system power-up, for example, the circuitry provides the ability to measure the impedance profile and thus the acoustic properties of the loudspeaker, enabling direct comparison to a factory calibrated profile stored nearby. Any changes in the impedance profile are detected and further diagnostics are carried out, preventing premature damage.

App note: Choosing the appropriate component from data sheet ratings & characteristics.

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Chossing the right power semiconductor for an application, a technical note from IXYS. Link here

This application note is intended to show how to choose the appropriate rating of a power semiconductor component for a known application using the specifications given in the datasheet. The explanations have been kept sufficiently general to be applicable to all common power circuits. However, for the sake of concreteness, they focus on IXYS IGBT modules and discretes respectively with or without diode. Proceeding as described in the following enables the designer to gain all necessary information from the data sheets for the most economic selection of power semiconductors.

App note: Voltage to current conversion

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Using Apex Microtechnology’s power op amps for voltage controlled current sources (VCCS’s) application note, Link here (PDF)

Voltage controlled current sources (or VCCS’s) can be useful for applications such as active loads for use in component testing or torque control for motors. Torque control is simplified since torque is a direct function of current in a motor. Current drive in servo loops reduces the phase lag due to motor inductance and simplifies stabilizing of the loop.

App note: Programmable power supplies

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Apex Microtechnology’s application note about programmable power supplies. Link here (PDF)

The programmable power supply (PPS) is not only a key element in automated test equipment, but it is also used in fields as diverse as industrial controls, scientific research and vehicular controls. When coupled to a computer, it bridges the gap from the software to the control task at hand. This application note examines the basic operation of the PPS, the multitude of possible configurations and the key accuracy considerations.

App note: Wear leveling in NAND flash memory

Application note/Technical note from Macronix on extending the maximum endurance limit of NAND flash memories by wear leveling. Link here (PDF)

NAND flash memory is widely used in today’s embedded systems for code and data storage applications. Some applications are required to perform numerous Program and Erase operations on the NAND flash memory after system boot-up. NAND flash memories are generally specified with a limited number of Program/Erase (P/E) cycles per block. If the P/E cycles are not evenly distributed across the memory, individual memory blocks can exceed their endurance specification limit. To prevent this scenario from happening, a technique known as “wear leveling” is widely used in NAND flash memory management. Essentially, wear leveling is a way to average out the number of P/E cycles across all usable blocks in a NAND flash device so that the number of bad blocks created over time as a result of frequent PE cycling is minimized. Today, wear leveling has become a critical part of NAND flash management in embedded systems that require frequent Program and Erase operations.