App note: How to select an ambient light sensor for your end equipment

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Another application note from Texas Instruments about ambient light sensors and how to effectively use them. Link here (PDF)

Generally, when someone thinks of trying to design a system with an ambient light sensor there are four main concerns or problems that need to be addressed. The most important features of an ambient light sensor are spectral response, power, size, and range of lux measurement.

App note: How to isolate signal and power in isolated CAN systems

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CAN system isolation app note from Texas Instruments, Link here (PDF)

With the increase in the usage of signal isolation in many industrial and automotive applications, the need for isolated power has also increased. The benefits of isolation are lost if the power supplies on either side of the isolation barrier are simply shorted. At the same time, if the isolated power sub-systems are not designed carefully, it affects the overall system performance like temperature rise due to poor power transfer efficiency, data corruption due to emissions, and so on. To simplify the design process of isolated CAN sub-systems, this document provides various options (discrete and integrated) to isolate CAN signals and power.

App note: Detecting selfie sticks using TI audio jack switches TS3A227E and TS3A225E

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Old app note from Texas Instruments on smart phone selfie sticks button detection. Link here (PDF)

Selfie sticks are becoming as common of a smart phone accessory as a pair of headphones. Because of the selfie stick’s increasing popularity, smart phone manufacturers need to be able to accommodate the accessory. This report describes the procedure required for a smart phone to detect when a selfie stick accessory is inserted into a smart phone’s audio jack receptacle using TI audio jack switches TS3A227E and TS3A225E. It shows how these devices respond to common selfie-stick implementations and how to adjust the audio jack switch’s register settings to accommodate both traditional audio accessories as well as the new selfie stick accessory.

App note: EMI-hardened operational amplifiers reduce inaccuracies

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EMI reduction built-in on op amps, app note from Texas Instruments. Link here (PDF)

Operational amplifiers (op amps) with electromagnetic interference (EMI) filters can reduce significant errors. These types of errors are not always obvious to the system designers. They often impact the signal chain, in particular the analog-to-digital converter in the form of a loss of digital counts.

App note: How to properly configure unused operational amplifiers

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Good read app note from Texas Instruments about configuring unused op amps on multi amp chips. Link here (PDF)

Multi-channel operational amplifiers (op amps) are often implemented in circuits that do not require the use of all channels. Undesired behavior in an unused amplifier channel can negatively impact system performance, as well as the performance of the channels in use. To avoid degradation of both the op amp and system performance, the unused op amp channels must be configured properly.

App note: Current sense amplifiers in class-D audio subsystems

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App note from Texas Instruments about output current sensing in class-D amplfiers. Link here (PDF)

Current sensing in audio subsystems are widely used in conjunction with CLASS-D amplifiers for diagnostics or to provide speaker current feedback to the DSP for speaker enhancement to emulate smartamp. The most expensive component in the audio subsystem is the speaker. The impedance of the speakers ranges from 2Ω for subwoofer to a 8Ω for stereo speakers. Exceeding the current flowing through the speakers has a potential to create excessive heat in the voice coil which can lead to permanent damage of the speakers.

App note: Implementation of a single-phase electronic watt-hour meter using the MSP430AFE2xx

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Another energy meter from Texas Instruments using MSP430AFE2xx. Link here (PDF)

This application report describes the implementation of a single-phase electronic electricity meter using the Texas Instruments MSP430AFE2xx metering processors. It includes the necessary information with regard to metrology software and hardware procedures for this single chip implementation.

App note: Extend current transformer range

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Design note from Texas Instruments on technique in resetting and negative voltage generation from current transformers. Link here (PDF)

Transformers are used extensively for current sensing because they can monitor currents with very low power loss and they have wide bandwidth for good waveform fidelity. Current transformers perform well in applications with symmetrical AC currents such as push-pull or full bridge converter topologies. In single-ended applications, especially boost converters, problems can arise because of the need to accurately reproduce high duty factor, unipolar, waveforms. Unipolar pulses may saturate the current transformer and, if this happens, overcurrent protection will be lost and, for current mode control, regulation will be lost and an over voltage condition will result.

App note: Understanding undervoltage lockout in display power devices

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Texas Instrument’s application note about how undervoltage lockout (UVLO) protect devices from undefined behavior. Link here (PDF)

Many integrated circuits include an undervoltage lockout (UVLO) function to disable the device at low supply voltages. Below the minimum supply voltage the function and performance of a device may be undefined, making it impossible to predict system behavior. This application note explains how to correctly understand the undervoltage lockout specification in the data sheets of TI’s Display Power products.

App note: Load switches: What are they, why do you need them and how do you choose the right one?

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Application report from Texas Instruments on load switches to simplify power supply design. Link here (PDF)

Integrated load switches are electronic relays that can be used to turn on and turn off power supply rails in systems. Load switches offer many other benefits to the system and can include protection features that are often difficult to implement with discrete components. There are many different applications where load switches can be used including, but not limited to:

-Power Distribution
-Power Sequencing and Power State Transition
-Reduced Leakage Current in Standby Mode
-Inrush Current Control
-Controlled Power down

This application note will provide the fundamental basics of what load switches are, when they should be used, and how they can be implemented in a system.