IKEA SMÅHAGEL USB charger teardown (shorter version)
For those who just want to know the bare facts about this charger, here's a super-short 2 minute version.
If you want to know more the full version of the video has schematics, circuit description and data on specific components.
https://www.youtube.com/watch?v=G0yrCSD3FAM
Long story short, it looks a well designed and safe charger. Just as we'd expect from IKEA.
It's also VERY affordable.