App note: Multiple Capture/Compare/PWM (MCCP): Extending the functionality for low-cost motor control applications


Microchip’s MCCP module on PIC32 devices demonstrate the built-in majority detection filter for simpler motor control drives. Link here (PDF)

The motor control industry has been focusing on designing low-cost motor control drives for various applications. The consumer demand for low-cost motor control applications is driving this trend.

Microchip has recently introduced the PIC32MM family of microcontrollers, which is capable of addressing the low-cost motor control requirements. The low-cost solution benefits from the capability of the Multiple Capture/Compare/PWM (MCCP) module available in Microchip’s PIC32MM controllers. This document
illustrates the usage of the MCCP module in the PIC32MM0064GPL036 controller, from Microchip Technology, to deliver a development platform for motor drive applications.

MCCP implementation, similar to the motor control solution discussed in this document, can also be extended to Microchip’s PIC24 and dsPIC33 family of devices which feature MCCP.

App note: Add a “Black Box” fault logger to your “Big (or Small) Box” system


Application notes from Maxim Integrated on adding log functionalities in your system. Link here (PDF)

This article describes how to add a “black box” functionality – nonvolatile fault logging – to networking, communications, industrial, and medical equipment. It outlines the benefits of recording fault data, including faster, more definitive failure analysis.

App note: Selecting current sensors and transformers


Selection guidelines from Coilcraft. Link here (PDF)

Current sensors detect the flow of AC or DC current in a wire or circuit trace. They can be used to detect an on/off/ pulse current condition or to measure the magnitude of the current in the wire or trace. This discussion is limited to AC current sensors. Ideal current sensors would not use any power to detect the current in the wire or trace, but real current sensors require some of the circuit energy to provide the information.

Current sensors are frequently used to measure and control the load current in power supplies, safety circuits and a variety of control circuits. In applications where controlling the current is required, such as in power supplies, accurately sensing the magnitude of the current is a fundamental requirement.

In pulsed-current applications or where it is only required to detect an on condition such as some safety circuits, the precise magnitude of the current may not be required. In other safety circuits, the sensed current can be used to trigger a shut down when the current exceeds a pre-set limit.

App note: IR remote control transmitter


IR remote control transmitter application note (PDF!) from Microchip:

This application note illustrates the use of the PIC10F206 to implement a two-button infrared remote controller. The PIC10F2XX family of microcontrollers is currently the smallest in the world, and their compact sizes and low cost make them preferable for small applications such as this one.
Two example protocols are shown. The first is Philips® RC5, and the second is Sony™ SIRC. These two protocols were chosen because they are fairly common and their formats are well documented on professional and hobbyists’ web sites. They also demonstrate two differing schemes for formatting the transmission.

App note: Solid state relays input resistor selection


SSR or solid state relays input resistor recommendation app note from Vishay. Link here (PDF)

Solid state relays (SSRs) are commonly driven by TTL or buffered CMOS logic gates. These gates, when used to sink current, provide adequate drive for SSRs. An open-collector output is not required to drive the SSRs, but it can be useful to perform a logic OR function.

A quick recommendation for 5 V power supply operation of most SSRs is to use a 560 ohm resistor. This combination provides an LED current range of 5 mA to 9 mA, thereby optimizing LED current, surge capability, and turn-on/off times. This calculation has taken into consideration power supply variations, temperature variations from – 40 °C to + 85 °C, and manufacturing variations. It uses a 10 % tolerance, 300 ppm/°C input resistor. Likewise, for operation to only 70 °C, a 680 ohm resistor would suffice.

App note: Audible noise reduction techniques for FPS (Fairchild Power Switch) Applications


Reducing audible noise in switch mode power supplies app note from ON Semiconductors. Link here (PDF)

In general, switched mode power supplies do not generate audible noise when they operate at constant ultrasonic frequencies (>20kHz). However, some switched mode power supplies can produce audible noise at certain load conditions. Most Fairchild Power Switches are designed to enter into burst switching operation at light load conditions to reduce standby consumption, which can cause audible noise when the fundamental frequency of the burst switching bundles is in the range of human hearing.

This application note explains the major sources of audible noise and offers useful tips to engineers to solve the audible noise problem in their Fairchild Power Switch (FPS) applications.

App note: Applications of zero voltage crossing optically isolated triac drivers


App note from Fairchild Semiconductors about their zero voltage crossing isolators. Link here (PDF)

The zero-cross family of optically isolated triac drivers is an inexpensive, simple and effective solution for interface applications between low current dc control circuits such as logic gates and microprocessors and ac power loads (120, 240 or 380 volt, single or 3-phase).

This paper describes the operation of a basic driving circuit and the determination of circuit values needed for proper implementation of the triac driver. Inductive loads are discussed along with the special networks required to use triacs in their presence. Brief examples of typical applications are presented.

App note: Using the Configurable Logic Cell (CLC) to interface a PIC16F1509 and WS2811 LED driver


An application note (PDF!) from Microchip on how to use CLC to interface a PIC16F1509 and WS2811 LED driver:

The Configurable Logic Cell (CLC) peripheral in the PIC16F1509 device is a powerful way to create custom interfaces that would otherwise be very difficult. One example is the single-wire PWM signal, used by the WS2811 LEDs, well known in LED video display systems. This application note will provide a simple demonstration of a WS2811 LED Strip driver.

App note: Transponder coils in an RFID system


A short application note from Coilcraft about transponder coils. Link here (PDF)

Radio Frequency Identification (RFID) is the system of using radio signals to send information identifying a particular situation or item. It can be used to track and locate any item including material, people and animals.

The RFID transponder coil is part of the coupling device and acts as the transmitting antenna. The key specifications of the transponder coil are sensitivity and read distance, however, the inductance of the transponder coil directly influences the sensitivity and the read distance. Generally, a higher inductance provides greater sensitivity resulting in a longer read distance. The manufacturer of the tag usually specifies the inductance of the coil to be used. The read distance is defined as the maximum distance from the reader that the transponder responds to the reader’s magnetic field.