Impact of MOSFET Gate Resistor on the EMI & Noise Spectrum of a Switch Mode Power Supply

In this video we will demonstrate why slowing down our MOSFET in a switching power supply can help us pass the EMC test. We will change our turn on and turn off times of our FET by changing our Gate Resistor and show its impact on the power supply's noise spectrum on a spectrum analyser
Please visit our website below to download the accompanying presentation PDF:
www.biricha.com/psudf-mosfet-...

[@jasongreene303]

This was my question in the previous video, thank you for a great explanation!

[@p_mouse8676]

Something that works super well, is using a ferrite bead in series with the gate resistor. (also available in SMD). If you choose these well, it will really knock down those pesky harmonics, while giving more room to keep the switching frequency a bit higher at the same time.

[@breedj1]

Excellent. Great explanation.

[@str8upkickyaindanuts289]

Outstanding demonstration, this is exactly what I was talking about in my comment on a previous video, this is the additional context needed to better understand the gate drive resistance selection. Well at least half of it, the radiated emissions are equally significant as conducted emissions demonstrated here. You are a great teacher, subscribed! It's difficult to know the right questions to ask when learning about subject material so when someone includes the hidden traps it's a little easier to understand the significance of component selection. It would be great to see this video linked with the others!

[@mahmoudgaber5347]

thank you very much for the informative presentation, big fan

[@jeyaramanr283]

Hi sir, Yes you are correct. We used this idea and worked for EMC RE to pass the limits. But this will increase loss and reduce efficiency.

[@alorro93]

Good explaination. Thank you.

[@MMichaa]

I think you missed to include the pdf in the description

[@krish2nasa]

Very informative. Thank you very much.

[@ibrahimcafe9586]

Thank you very much sir

[@ElectroWiz]

خیلی خوب و کاربردی بود ممنونم

[@akrcusat]

Thank you

[@esijal]

Excellent and thank you

[@afonsomanuel1585]

What a excelent video, like always.

[@olivermeyer9460]

Thank you very much.

[@user-ig9fu6xr2p]

❤❤❤

[@jluke6861]

Thank you.

[@shekar9237]

Super

[@andymouse]

Is it possible to say at what frequencies this starts to be needed or necessary please ? just subbed hobbyist here ....cheers.

[@bhushanparate9601]

Hey, what if I am getting certain freq oscillations in the rise time and it is causing failure in EMC testing. how do I overcome that any thoughts?

[@PSPS437]

Snubber will help

[@anismelki8482]

Hello, can you please share pdf and reference schematic of you eval board used on this explanation.

[@frankcellini9363]

I don't know if you can help with this odd behaviour... I hade built a power supply that powers 2 external Hard Discs, based on the power available on computer's USB port. When computer starts up power supply turns on first HD (12VDC) and a few seconds later (after startup current settles) the second HD is powered. The power is switched with MOSFET transistors controlled by a PICAXE PIC microcontroller (powered by 5VDC). As soon as first drive is powered on, immediately the second MOSFET switches on, without any voltage at its gate (0V). Very strange! It should turn on a few seconds later when PIC applies 5V on gate? The PIC outputs are connected to MOSFET gates with 330ohm resistor to limit PIC current. The gates is also tied to ground with 10K resistor. If the loads (HDs) are not connected, circuit behaves correctly. (I also have LED/resistor across output to show on/off state). I fail to understand how the MOSFET can turn on without any gate voltage?

[@jitendranagda4687]

Sir this is for same resistor value for Turn on and off, if we use different resistor one for turn on and one for turn off with diode, How it will act??

[@chandrasekhar744]

Sir how to reduce the noise in DC system with FPGA