Safely use trench MOSFETs on hot swap application by determining its operation within its SOA in a limited time, app note from International Rectifier. Link here (PDF)
Hot Swap circuits are used to allow for “Hot Plugging” of circuit boards into back planes. The applications that require such functionality are mission critical, such as servers and communications equipment that must operate continuously. These circuit boards are usually employed in a rack mount system which consists of an array of boards that cannot be powered down. Thus hot swapping allows for a bad board in the array to be replaced without powering down the entire system.
In essence the Hot Swap circuit, which is between the board input rail and the rest of the board’s circuitry, is an inrush current limiter that allows for charging of the bulk capacitance in a controlled manner. Also faults, such as over current and overvoltage are managed by Hot Swap circuits.
Application note from International Rectifier on MOSFET paremeters to consider when designing a Class D audio amplifier. Link here (PDF)
Class D audio amplifier is a switching amplifier that consists in a pulse width modulator (with switching frequency in order of several hundred kHz), a power bridge circuit and a low pass filter. This type of amplifier has demonstrated to have a very good performance. These include power efficiencies over 90%, THD under 0.01%, and low EMI noise levels that can be achieved with a good amplifier design.
Key factors to achieve high performance levels in the amplifier are the switches in power bridge circuit. Power losses, delay times, and voltage and current transient spikes should be minimized as much as possible in these switches in order to improve amplifier performance. Therefore, switches with low voltage drop, fast on and off switching times and low parasitic inductance are needed in this amplifier.
MOSFET have proved to be the best switch option for this amplifier because of its switching speed. It is a majority carrier device, its switching times are faster in comparison with other devices such as IGBT or BJT, resulting in better amplifier efficiency and linearity.
Dilshan Jayakody writes, “This is an automatic Cat6 / Cat5 network cable tester designed using NE555 timer and 4017 decade counters. This unit test all 8 wire lines of twisted pair network cable and indicate pass/fail status with single LED. We design this unit to test network connectivity issues in Cat6 / Cat5 cable systems and it is capable to check both crossover and straight-through type network cables.”
This is the first video in the LinuxFu series designed to take you from knowing nothing about Linux to knowing everything. This first episode we’ll be looking at a bit of history, what Linux is and what makes it so special. The Who & Where – A bit of history Continue reading LinuxFu #01: What Is Linux? // Technology→
This week’s Weekly Roundup we’re seeing gesture sensors, ESP32, SBCs, Vehicle OBD boards and buck converters. Kickstarter First up on Kickstarter there’s … PLD/HL2 Panorama a multi-protocol wireless box that can talk Sigfox, LoRaWAN and SCAP/LTP. It contains an ATmega328P, which is the ultra low power variant allowing it Continue reading Weekly Roundup #43 – New Maker Products→
My Xi 8088 homebuilt PC is running a little short on slots, so I wanted to combine the functions of a game control adapter and an 8255 PIO board. Two functions in one slot. As to why one wants each of these things:
A game control adapter is used to interface to PC joysticks. These are the old-style analog joysticks with the 15-pin connectors.
An 8255 board is a general purpose interfacing board, providing 24 bits of digital IO that can be configured as inputs, outputs, or a mix of both. This is not in and of itself a “parallel port”, but could probably be used to implement one.
App note from Vector on three commonly encountered high speed CAN physical layer problems – bus termination, signal levels, and ground. Link here (PDF)
Determining the exact cause of a CAN problem is not at all simple.
Is the problem in hardware or software? Is the problem on the circuit board or on the CAN network wiring?
Sometimes the problem may not be at the module level – perhaps the cause is up at the system level.
This application note discusses methods used to investigate serveral of the more common CAN Physical Layer problems typically encountered when debugging high-speed CAN.