Choosing MOSFETs | So Many Options! - Circuit Tips and Tricks
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- เผยแพร่เมื่อ 2 ก.ค. 2021
- Choosing MOSFETs | So Many Options! - Circuit Tips and Tricks
The long awaited follow up to my original MOSFET video. This focuses on how to decide which specific MOSFET to choose. I also clarify something I missed covering in the first video.
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So perfect, almost all other videos start with a component and build a project around it, whereas you start with a project and show how you select components.
This, and the predecessor video, are sooo good! They give an additional level of understanding beyond the typical "how to make a MOSFET switch" videos, and with actual calculations. I love it :-D
Thanks for sharing this! I like the hand-on and pragmatic approach to your selections and find it very straightforward and understandable. Thanks!!
Glad it was helpful!
I love this video, easy, direct, and to the point.
Have you thought about doing a follow-up video to address GAN FETs and their drivers? For higher voltage circuits the EPC and others look very interesting to me, such as the EPC2305ENGRT.
Very intresting thinking. Great Video!
This is just the kind of video I've been thinking of doing for years, whenever I finally get around to starting a channel. Awesome to see someone else taking this approach.
very informative video,thank you sir
Wow, another detailed video. I now feel reasonably confident to pick out some power FETs that should work well the first time for my rather odd project. Thanks!
For calculating the max switching frequency will it not be limited by RC settling?
Gate Charge @10V = 42nC
Gate Cap = 42nC/10V = 4.2nF
Rdriver = 5.1 Ohm
T5RC = 5*5.1*4.2n = 107ns
F5RC = 1/(2*107n) = 4.7MHz
Also you say the driver has a max current 4.7A but if:
Vdriver = 12V
Rdriver = 5.1 Ohm
Idriver max = 12/5.1 = 2.4A
What a great video! It provides and excellent understanding of the requirements and component selection process.
You make exceptional videos. My favorite source easily.
Yes!!! You made this video! Thank you so much. :D
You are so welcome!
good video. thank you!
TH-cam suggested your vids at quite a good time for me... All that's missing now is something on inductive loads, I have a project that's going to have a fair inductive load on a mosfet.. already took a good look at that NCP gate driver which looks well suited. In my case I'm looking at a coil with a resistance of 1.3 ohm and 35mH run at a nominal 12V, probably drive in in the 5-20 khz range,..
Good minimum calculation and speedy selection process!
Hehe yeah maybe you can save time by testing instead of looking up all the data and calculating everything.. But before you can test it, you'll need to order it as well, so then you need to factor in the time it takes for it to be delivered. But I get what you're saying. With the amount of mosfets out there if you're trying to calculate everything, you could easily descend into analysis paralysis and never come to actually select a part to order, which causes even more delay..
By the way, we're only talking about N channel mosfets here, but I've had several use cases for p channel as well.. For instance, in an EEPROM programmer that I'm working on, I have multiple power options for different chip types, so I need to switch on and off ground and power lines using a microcontroller. I typically switch the ground lines with N channel mosfets, but I switch the positive power lines using a combination of an N channel mosfet that grounds the gate of a P channel mosfet (or in the case of a 5V power line I just drive a P channel mosfet with an inverted output from the MCU directly, using a 0 to switch it on).
But even the N channel and P channel mosfets we're talking about here are enhancement types.. What would be some use cases for N or P channel depletion type mosfets? And what are some "common" depletion type mosfets that I could experiment with? I tried to find some, but it seems there is much less choice in that area..
Nice video, thanks for sharing it, keep it up :)
Thanks like always intersting video👍
Glad you enjoyed it
Great video as always. Please do a GaN design video.
great. testing prototype gunna save a lot of time
I'd love to see a follow up of the device under test
Yes! I am planning on it
Thank you
Great video on describing the PWM calculation and selection, clears a lot of immense research and confusion for DIYers. I have one question, lets say that the frequency needs to be 50Mhz, how do we know for a fact that the Mosfet is able to drive at that frequency, are there any specification on the datasheet that gives an idea what the maximum ideal frequency the mosfet can handle if the circuit is properly designed? Thanks.
Mint!
Great subject for a video... this is a source of great confusion for me... but those screen shots? Ouch! Some of us watch this stuff on our phones... and I can't read a thing.
How do you derate for forced air convection (with a heatsink of course)?
How would you add a heatsink for the SMD in scenario 2?
Why should i care about the gate charge, when i have a gate driver that can dump a few amps?
You normally don't ;). That's a big reason to use a dedicated gate driver. But still, when switching at really high speeds it can become an issue again.