Peer-to-peer, engineer-to-engineer questions and answers from the EDABoard.com engineering community around power electronics. Click the “Read more” link and follow the entire conversation and maybe add your two cents by logging in to EDAboard.com

24V to 5V buck converter – I want to design a simple buck converter that converts a 24V input to a 5V output. I made a schematic but it doesn’t work, it gives a higher output voltage (even when I reduce the duty cycle to 1%) than desired which is confusing me. Could anyone please tell me where the problem is? Read more

Simple power supply with noise problems – I’ve got this simple power supply with clean sinusoidal input, but after the bridge rectifier some noise is introduced and I have no idea why. Read more

DC-DC step down possible circuit? –  I want to step down solar panels and a waterfall generator to 12V. It does not need to be very efficient and can be quick and dirty. Could this work? Kind of like a hybrid between a linear supply and a buck converter. Or is this just a dead end idea? Read more

Possessed IGBT will not turn ON – I made a PCB for my power supply and assembled it, but now Q2 won’t turn ON, and I swear it did when it was a rats nest. I have tested Q1, and that one works fine, but Q2 just makes a little 1uS burst on pin2/q2 even though the gate pulse is 50uS. And if I connect pin3/u6 directly to the gate pin1/q2 it still only makes that 1uS burst on pin2/q2 regardless of how long I keep the connection. (q1, q5 and q6 are off at the moment). Either Q2 must be possessed or I’m missing something obvious. Read more

Choosing MOSFET for boost converter – I have a circuit with one 150W MOSFET.If I want to double the current load, is it better to parallel the MOSFET or use a 300watt rated MOSFET? Read more

Flyback converter – Could anyone please clarify for me how this flyback circuit work? You’ll find attached the circuit and the properties of the transformer TR1. Read more

 

 

 

 

Multiple relays with controllers – In my project, there are 8 relays use. To reduce the usage of I/O pins from PIC controller. I tried to use multiplexer and shift registers. If the multiplexer is used it means I can’t switch ON the pair of relays at the same time. Read more

Voltage inverter feedback for microcontroller – I am trying to develop a feedback system for my sine wave inverter.
The power is shifted to 12V using a voltage divider, as we can see in the diagram below. The intention is to use the TL431 together with the 4N25 to isolate the output circuit of the control circuit to maintain safety and prevent interference from switching. However, the prototype was assembled and results were not expected. Read more

 

Gate driver with fault detection – I am looking for an off the shelf gate IGBT/ MOSFET driver that detects faults and discriminate between short and open circuit fault. I searched all major distributor and looked at numerous datasheets, but I could not find one. Read more

Hbridge control from MCU – In the past, I’ve connected an Arduino to MOSFETs.  One MOSFET is a low side switch and the other PMOS is controlled by another NMOS allowing the Arduino to run it from 0-5V although the power supply may be 20V for instance. But I was wondering if I cant dispense with the extra NMOS running the PMOS by running the Arduino output as an input which has high impedance? Read more