Should you buy a GaN Power Adapter? Or is it a scam? Testing GaN FETs!
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Date: 2021-03-21
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Comments and reviews: 10
tenkowal
So, a randomly picked GaN is better than a randomly picked MOSFET. Measuring their RDSON is just silly, as you could just look into their datasheets and read the values (and also cherrypick transistors to get preferred result.
Measurement of turn off and turn on times is also flawed. Your generator most likely has 50 ohm series resistance, which (along with 1 ohm resistor and needless transformer) are slowing down the gate charging process. You could also just open the datasheets of the transistors and read the values there, which you did, but did not make any remark about how picking different transistors would give different results, as MOSFETs and GaNs come in whole variety of parameters - there are series of transistors made with same parameters, but different tradeoffs between RDSON and gate charge.
Your GaN ringing is a result of absolutely horrible layout. GaN are fast and thus are susceptible to poor layout with parasitic inductances all over the place. There is no capacitance on the 12 V close to the switching circuit, hence it will oscillate. I've worked with GaNs in QFN packages with practically perfect layout and they still oscillated a little, so a circuit made with wires and THT packages just has to resonate madly.
Scott, what's happening? It's second video of yours I've seen recently which is below the quality you've set in past years.
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So, a randomly picked GaN is better than a randomly picked MOSFET. Measuring their RDSON is just silly, as you could just look into their datasheets and read the values (and also cherrypick transistors to get preferred result.
Measurement of turn off and turn on times is also flawed. Your generator most likely has 50 ohm series resistance, which (along with 1 ohm resistor and needless transformer) are slowing down the gate charging process. You could also just open the datasheets of the transistors and read the values there, which you did, but did not make any remark about how picking different transistors would give different results, as MOSFETs and GaNs come in whole variety of parameters - there are series of transistors made with same parameters, but different tradeoffs between RDSON and gate charge.
Your GaN ringing is a result of absolutely horrible layout. GaN are fast and thus are susceptible to poor layout with parasitic inductances all over the place. There is no capacitance on the 12 V close to the switching circuit, hence it will oscillate. I've worked with GaNs in QFN packages with practically perfect layout and they still oscillated a little, so a circuit made with wires and THT packages just has to resonate madly.
Scott, what's happening? It's second video of yours I've seen recently which is below the quality you've set in past years.
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education
Hi Scott, GaN PD charger is already quite popular in China, to a point where most people buy one right away if they have a new MacBook / laptop that supports PD. Also I wouldn t trust the charger you ve got as they are not well known brand even in China. There s a very useful website (unfortunately Chinese language only so you ll need google translation) called www. chongdiantou. com which does in-depth testing, review and tear down of chargers and power banks (mostly GaN nowadays, as well as articles on GaN components and supply chains, worth taking a look.
P. S. feel free to contact me if you need help on understanding any of the articles on the website. Great content as always!
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Hi Scott, GaN PD charger is already quite popular in China, to a point where most people buy one right away if they have a new MacBook / laptop that supports PD. Also I wouldn t trust the charger you ve got as they are not well known brand even in China. There s a very useful website (unfortunately Chinese language only so you ll need google translation) called www. chongdiantou. com which does in-depth testing, review and tear down of chargers and power banks (mostly GaN nowadays, as well as articles on GaN components and supply chains, worth taking a look.
P. S. feel free to contact me if you need help on understanding any of the articles on the website. Great content as always!
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Marinus
I missed the important emphasis on the fact that if the whole world moves on to GaN MOSFET's, the power save will be huge, even if it's only a few percent and only in the products that actually use them of course. So, for one person it might not seem to make a big difference, but when talking about quantity, this is a great development worldwide on a bigger scale: )
The downside will be that it implies that all the equipment in use today will have to be moved to electronic waste, these things cost power to produce, so in theory, I think it doesn't make much of a difference for at least 50 years. But after that it will start paying off.
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I missed the important emphasis on the fact that if the whole world moves on to GaN MOSFET's, the power save will be huge, even if it's only a few percent and only in the products that actually use them of course. So, for one person it might not seem to make a big difference, but when talking about quantity, this is a great development worldwide on a bigger scale: )
The downside will be that it implies that all the equipment in use today will have to be moved to electronic waste, these things cost power to produce, so in theory, I think it doesn't make much of a difference for at least 50 years. But after that it will start paying off.
reply
Richard
Great video! I was skeptical when I first saw GaN chargers. I didn't doubt the tech, just the companies that advertise using it. Glad to see this is something real and tangible for mass production unlike X college students discover Y battery tech to charge an electric car in 2 seconds! , However, it's still crazy to see your product was actually missing the component it needed. You should take a closer look, I'd love to see if they snuck a small one in for something useless, like driving an LED. Thanks for the info and your investigation!
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Great video! I was skeptical when I first saw GaN chargers. I didn't doubt the tech, just the companies that advertise using it. Glad to see this is something real and tangible for mass production unlike X college students discover Y battery tech to charge an electric car in 2 seconds! , However, it's still crazy to see your product was actually missing the component it needed. You should take a closer look, I'd love to see if they snuck a small one in for something useless, like driving an LED. Thanks for the info and your investigation!
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Splod
Great content about a type of FET I hadn't heard of, thank you. I enjoy your videos, but (and feel free to ignore me) for some reason I find the way you go over and over your writing with a pen and highlighter really annoying. I realise you are just emphasising your writing but I have to skip over those parts so I don't see your highlighter soaking up more pen ink or the pen going through the wet paper. Maybe it's an OCD thing but I really don't like it.
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Great content about a type of FET I hadn't heard of, thank you. I enjoy your videos, but (and feel free to ignore me) for some reason I find the way you go over and over your writing with a pen and highlighter really annoying. I realise you are just emphasising your writing but I have to skip over those parts so I don't see your highlighter soaking up more pen ink or the pen going through the wet paper. Maybe it's an OCD thing but I really don't like it.
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Andrius
once I've tried improve monitor efficiency by replacing its MOSFET to more efficient one. Got one with 5times lower Rds (on) value and this thing showed magic smoke after few hours: D then i discovered that Chanel capacitance in new MOSFET was higher and loses remain the same. So LG made already good job back in 2006. ( in my country) was hard to find better MOSFET than original one.
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once I've tried improve monitor efficiency by replacing its MOSFET to more efficient one. Got one with 5times lower Rds (on) value and this thing showed magic smoke after few hours: D then i discovered that Chanel capacitance in new MOSFET was higher and loses remain the same. So LG made already good job back in 2006. ( in my country) was hard to find better MOSFET than original one.
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Halbostfriese
Still think GaN is a scam. While the tech and theory behind it are legit, you still get regular old MOSFETs in the Chinese devices you buy, even if marketed as GaN.
A solution may be not to buy Chinese manufactured electronics, but. good luck with that.
This is the very same deal as with the Chinese powerbanks with ridiculous capacities.
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Still think GaN is a scam. While the tech and theory behind it are legit, you still get regular old MOSFETs in the Chinese devices you buy, even if marketed as GaN.
A solution may be not to buy Chinese manufactured electronics, but. good luck with that.
This is the very same deal as with the Chinese powerbanks with ridiculous capacities.
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JL
Love the video, but seriously, get rid of the cheapo solder helping hands clip bits on the base.
Quadhands. com seriously is much better, not doin an affiliate link, etc. Just really good for detailed EE/solder work, and def worth the cost. I'm not schilling for them, I just randomly tried them, and yea, the better quality is worth the cost.
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Love the video, but seriously, get rid of the cheapo solder helping hands clip bits on the base.
Quadhands. com seriously is much better, not doin an affiliate link, etc. Just really good for detailed EE/solder work, and def worth the cost. I'm not schilling for them, I just randomly tried them, and yea, the better quality is worth the cost.
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Teth47
Another major advantage of the GaN MOSFETS is that since they draw less power and require less beefy gate drive circuitry for the same switching speeds, you can make devices significantly more compact without sacrificing capacity. I think the biggest consumer draw is your charger is less of a brick.
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Another major advantage of the GaN MOSFETS is that since they draw less power and require less beefy gate drive circuitry for the same switching speeds, you can make devices significantly more compact without sacrificing capacity. I think the biggest consumer draw is your charger is less of a brick.
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Forthereg
We already have 93%-94% PSUs in our computers.
overall topology and design is way more important. So at the moment bill of material budget can be better spent elsewhere than on a GaN.
but yeah, i think we will get slightly better (consumer) electronics 3 or 5 years down the line.
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We already have 93%-94% PSUs in our computers.
overall topology and design is way more important. So at the moment bill of material budget can be better spent elsewhere than on a GaN.
but yeah, i think we will get slightly better (consumer) electronics 3 or 5 years down the line.
reply
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