Car charger

Some companies have been distributing these simple car power adapters - takes 12v in from car cigarette lighter and puts out 5v at whatever current. As they're often freely available at trade fairs, I've ended up with few.

Currently I have a specific one at hand, which appears to be distributed by a norwegian company, and promises 5v @ 700mA. And of course it, after some time of use, doesn't work anymore. Not too surprising, really, I expect these things to be really cheaply made.

After opening it up, I found pretty much what I expected. Simple buck converter, using a chip labeled AD85063. Well, at least this one is kinda honest - this chip is rated max 700mA. There appears to be quite a few of similar adapters that promise something like 2 amps, using this same chip.

The bad part; there appears to be no real protection on the chip, and no real current limit anywhere on the circuit. USB data pins are shorted, so devices can pull high currents, damaging the chip in process. And, apparently, based on few posts I've found, the failure mode of this chip isn't very pretty - it'll short the input to the output after which there's plenty of +12v coming in the USB. This can happen with buck converter if chopper transistor shorts out, which seems to be all too common failure mode. Hope the protections in phone are up to their job.

Now, I have few of similar converters around here, looking almost same but this one is with 2 ports and higher output current rating (total over 3 amps). Now I'm kinda curious to open it and see what's inside...