BUS PIRATE: three inexpensive SPI Digital to Analog Converters

As much as possible, we’d like to move control of all the Bus Pirate peripheral hardware to the FPGA. Then everything can be controlled through the state machine command pipeline. In Ultra v1c we moved analog voltage measurement to the FPGA by adding an SPI ADC. In a future revision it would make sense to […]

App note: MUX-friendly precision operational amplifiers

Another App note from Texas Instruments on op-amp input safety from breakdown voltages during source switch-over. Link here (PDF) Multiplexing is a frequently used technique to perform data acquisition in multichannel systems with minimal signal-chain requirements. In this context, the role of the multiplexer (MUX) in an acquisition system is to switch between channels, and […]

App note: Precision current measurements on high-voltage powersupply rails

Two methods for measuring current and what sense amplifier used are tackled in this app note from Texas Instruments. Link here (PDF) Current is a signal that can provide valuable insight into how a system is operating. Under defined conditions, the amount of current required to perform a task is consistent, making the current information […]

App note: Simplify home audio systems With the PCM9211 – A versatile audio interface transceiver

A digital interface PCM9211 from Texas Instruments app note. Link here (PDF) Large-screen HDTVs are selling in huge volumes over last few years, primarily driven by amazing improvements in picture quality & form factor (thinner screens). The form factor constraints from having skinny screens result in tiny built-in speakers that are undersized, under-powered and are […]

App note: Overcurrent event detection circuit

Sample overcurrent detection circuit from Texas Instruments. Link here (PDF) This is a unidirectional current sensing solution generally referred to as overcurrent protection (OCP) that can provide an overcurrent alert signal to shut off a system for a threshold current and re-engage the system once the output drops below a desired voltage lower than the […]

App note: Active filtering in automotive audio applications

App note from Texas Instruments on isolating DC and high frequency noise in audio using their automotive op amps. Link here (PDF) Phone calls, emergency alerts, and music are just a few of the reasons that a high quality audio system is vital in automotive infotainment and clusters. Operational amplifiers (op amps) are one of […]

App note: Capacitive sensing: Direct vs remote liquid-level sensing performance analysis

Capacitive liquid level sensing method comparison discussed in this app note from Texas Instruments. Link here (PDF) Capacitive-based liquid level sensing is making its way into the consumer, industrial, and automotive markets due to its system sensitivity, flexibility, and low cost. With using TI’s capacitive sensing technology, the system flexibility allows designers to have the […]

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

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 […]

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

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 […]

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

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 […]

App note: EMI-hardened operational amplifiers reduce inaccuracies

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 […]

App note: How to properly configure unused operational amplifiers

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 […]

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

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 […]

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

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

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 […]

App note: Understanding undervoltage lockout in display power devices

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 […]

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

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 […]

App note: Low-power battery temperature monitoring

Low current consumption temperature battery monitoring TMP303 from Texas Instruments. Link here (PDF) Charging a battery cannot be independent of temperature. In fact, most batteries specify a range of temperatures where charging is permitted. Charging outside these bounds risks damage, failure or worse. To prevent charging when the temperature is too hot or too cold, […]

App note: Stopping reverse current flow in standard hot swap applications

Application report from Texas Instruments about a simple circuit that blocks reverse currents. Link here (PDF) The proposed circuit uses an inexpensive operational amplifier to sense the condition of the output voltage exceeding the input voltage, and subsequently disable the hot swap controller, stopping the flow of reverse current (current flow from the output (load) […]

TI’s Little Professor

A teardown of TI’s Little Professor vintage calculator from KuzyaTech: This thing was sold for parts and repair since the seller did not think it was working. As it turned out, everything worked just fine, but not in an expected way. This is not your typical calculator, but rather a teaching one. More details at KuzyaTech.com.