App note: Op-amp/comparator module for dsPIC

Some dsPIC33E and PIC24E microcontrollers have an comparator module that can function as an op-amp [PDF]. The module can be used as a simple non-inverting amplifier by adding two external resistors, no external op-amp chip needed. The output can be read internally by the ADC module, or routed externally to use in your circuit.

App note: Understanding and preventing LED Failure

When using LEDs in projects it’s good to know what could cause their failure, and design your device to prevent it: LEDs have a well-deserved reputation for high-efficiency operation, not to mention high reliability. Properly specified and implemented, LEDs should and do satisfy virtually every lighting application. Still, there are times when actual device lifetimes […]

App note: Enhancing ADC resolution by oversampling

Better ADC resolution can be accomplished by oversampling two or more ADC readings and then averaging them. If you’re not satisfied with a microcontroller’s 10 bit ADC and need more resolution, check out this application note from Atmel. Increasing the ADC resolution by one bit requires 4 ADC measurements.  Four 10 bit readings are needed […]

App note: Interfacing 4/5/8 wire resisitve touch screens

Resistive touch screens are pretty cheap, and make it easy to interface with device without placing a lot of buttons. This app note describes how to interface with 4, 5, and 8 wire resistive touch screens on your next project. All analog touch screens consist of a ridged layer and a flexible layer with a […]

App note: Advanced 1-Wire Network Driver

This reference design shows how to drive long 1-Wire networks. 1-Wire is a communications protocol used by some Dallas/Maxim parts. The protocol uses only one wire for power, transmission, addressing, and synchronization. This document describes a microcontroller-based 1-Wire master interface for reliable operation of small, medium size and large 1-Wire networks. This is accomplished using […]

App note: File IO function reference for Microchip’s Memory Disk Drive File System Library

Here is a function reference for Microchip’s memory disk drive file system library. This library interfaces a PIC microcontroller with FAT16 or FAT32 file systems. It allows you to interface with storage mediums like USB flash drives or microSD cards in the same way a PC would. Save data on a storage device, and later […]

App note: HV boost power supply for Nixie tubes

Here is a app note from Microchip describing how to implement a high-voltage boost DC-DC converter intended for Nixie tube designs. The basic principle of Nixie tubes is that they require more than 170V to function properly. This design uses the internal PWM generator of a PIC16 microcontroller to drive the DC-DC converter. A comparator […]

App note: Buck-boost converter

Here is an article from Texas Instruments featured on EETimes describing how to design a buck-boost converter. These converters are used when the input voltage can be both above and below the output voltage. One example are 3.3V systems powered by lithium-ion batteries which swing from ~3V to ~4V. This design is in effect a […]

App Note: Optimizing visibility and battery life of portable displays

Here is an app note from Maxim describing how to implement light intensity sensing in the visible spectrum. This is used to adjust the brightness of displays in portable devices. Human eyes only perceive a limited light spectrum. Sensors used to detect light intensity require complex conversions of their spectrum to emulate human eyes. Another […]

App note: Trouble shooting EZ-USB FX USB peripheral ICs

Here is an app note from Cypress with design guidelines for their EZ-USB FX1 and FX2LP USB peripheral ICs. They are basically 8051 microcontrollers with a built in USB serial interface engine. While these devices are easy to use, sometimes getting a new board up and running is tricky  due to the various details that […]

App note: PSoC I2C to SPI bridge.

Here is an app note from Cypress that describes how to implement a I2C to SPI bridge on a PSoC IC. PSoCs are devices that incorporate a microcontroller, a logical gate array, and some analog peripherals. What makes them different than microcontrollers is that all the peripherals are separated from the microcontroller. They can function […]

App note: Single battery boost converter

Here is an app note from Microchip that describes how to built a single battery boost converter. It provides a way to power higher voltage circuits with a lower voltage battery. The design is based around the MCP1640 IC. It is a 350mA 500Khz boost converter with an integrated switch. Due to it’s design the […]

App note: Dual 1.4MHz buck regulator with USB ‘Dying Gasp’ support

This app note from Maxim describes how to build a USB powered circuit that will provide a short power-failure notice before losing power. This is called the “Dying Gasp” and it allows devices to preform a proper shut-down when USB power fails. A safe USB “dying gasp” shutdown requires a local energy storage capacitor to […]

App note: Pushbuttons Control Regulated Switching Converter

Here is an app note from Maxim describing how to implement a digital potentiometer to adjust the output of a boost converter. Digipot is controlled through two push buttons. One controls the direction of the wiper, while the other moves the digipot wiper in the selected direction. The digipot is implemented on the DC/DC boost […]

App note: Implementing bidirectional interface with a single common LED

Here is an app note from Mitsubishi Electric Research Laboratories describing how to implement short-range low-bandwidth bidirectional communication using common LEDs. It’s called LEDComm and requires only two pins of a microcontroller and a current limiting resistor to function. It works by making use of the fact that LEDs, once reverse biased, are also pretty […]

App note: 1000VA Digital pure sine UPS

Here’s a reference design from Microchip for a 1000VA pure sine uninterpretable uninterruptible power supply. UPS usually use 3 circuits to function. A charger for battery, a inverter to convert DC battery power to mains AC, and a controller that switches from mains to battery when the power is interrupted. This design utilizes a single […]

App note: Battery/charger load switch approximates ideal diode

Portable devices require a circuit that switches the power supply between battery and charger. This is usually done by using a diode on the battery line – when the charger is plugged in, the diode is reversely polarized and disconnects the battery from the rest of the circuit. This method however has drawbacks, namely power […]

App note: Acoustic thermometry

Orcinus tiped us about this interesting app note on acoustic thermometry from Linear Technology: People usually measure temperature in order to correct the distance determined using ultrasonic transducers. Acoustic thermometry takes the opposite approach – the distance is fixed and the time it takes for an acoustic pulse to make a round trip is used […]

App note: Layout and physical design guidelines for capacitive sensing

We think DIY capacitive touch sensing buttons, and sliders are cool. Designing and shaping your capacitive panels can be a pain. Here is an app note by Microchip that covers all the basics required to get your capacitive touch sensing project started. This app note starts with which pad shape and size is best suited […]