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We have been hearing about gallium nitride power semiconductor since 2010 / 2011, and then again in 2014/2015, Why did it take so long to come to market? Cost?

( If it is cost then there is no hope of a nickel and dime fruit company to include it by default )

Mainly cost. Right now a GaN mosfet costs 10x more than a silicon one of similar power rating.

You are starting to see them in consumer goods where they can reduce the total system cost, or get the size down in premium goods.

For higher power stuff, they have to compete with silicon carbide which can handle very high temperatures, so your cooling needs are smaller.

[0]: IPAW60R380CEXKSA1 (silicon) costs $1.27, IGT60R190D1SATMA1 (GaN) costs $13.

Thanks... There goes my hope of Apple having it come with iPhone. $10 BOM is A LOT.

Cost, and the fact that it doesn't actually buy you much. I've evaluated GaN for a couple recent designs I've been involved in and found that its benefits simply didn't justify its costs.

What GaN actually does is, mainly, decrease switching losses. That means switching frequency can go up, or efficiency, or power density. These are all good things, to be sure, but the magnitude of improvement GaN brings to most designs is simply not large enough to justify the cost of the parts and the increased design attention needed to use them. (They're fussy little things.)

That said, I'm bullish on GaN in the medium-term. There are some cool tricks that are infeasible or impossible without them, and they really are better in a lot of ways. It'll just take a while for them to trickle downmarket, and even still they're not going to be replacing Si FETs anytime soon. (Part of the lag in GaN adoption is simply that Si FETs have gotten really, really good.)

Same opinion. If someone needs to improve power densities over buck, they will first switch to a better topology.

The main advantage of GaN is to allow simple buck converter to get smaller, and improve their power density. The biggest advantage is really the size.

May I know, are you working in electronics?

>The biggest advantage is really the size.

Which basically means no one is making enough marketing about this use case. Size of charger matters a lot. If it was Apple they will be very loud about it as Innovation. ( At least Consumer are willing to pay for it )

(To GP: Yes, I'm an electrical engineer.)

Yes, size is the main product-level advantage of GaN. But it only lets some of the system shrink; for something like a mains charger, you still need the isolation magnetics, so your overall size is still constrained. And at the power levels of a few watts that many chargers work with, Si FETs are simply good enough. A 5W USB charger isn't going to get any smaller with GaN. It only starts to get interesting with really high power densities.

> But it only lets some of the system shrink; for something like a mains charger, you still need the isolation magnetics, so your overall size is still constrained.

1. You can isolate with caps... if you trust their manufacturer. http://www.helixsemiconductors.com/uploads/cms_uploads/2018/...

2. Well if things go this way, one can go for "virtual isolation" with beefy mosfets, and pray that the gate fail before the junction melts to pieces. This is actually what apple recently patented.

Nice to meet an actual engineer here. What is your field of work?

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