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 )
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.
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?
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?