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Comment by Causality1 | Hacker News Reader

It would be interesting to get a real expert's explanation of how the ways the Nintendo Switch violates the USB specifications leads to third party docks sometimes frying consoles, or maybe an explanation of how phone manufacturers can charge batteries at absurd C rates without killing them.

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> third party [Switch] docks sometimes frying consoles

Simple: an early third-party dock for the Switch, made by Nyko, implemented USB-C incorrectly and could deliver up to 9V on the CC1/CC2 (configuration channel) pins. These pins are only supposed to have 5V on them, and a USB-C interface IC in the Switch was frequently damaged by that voltage.

The Switch was fine. The fault was entirely in the dock.

The Switch violates protocol in many ways: https://web.archive.org/web/20190201011444/https://plus.goog...

From what I'm reading, most of the violations Nathan is complaining about are on the part of Nintendo's dock, not the Switch itself. Moreover, these violations are all relatively minor (especially compared to Nyko's 9V CC howler!) and are unlikely to cause any serious issues under normal use.

The point was not whether the implementation in the Switch was perfect, it was about frying the console. Minor spec violations won’t do that, but a wildly out-of-spec charger might.

> The Switch was fine. The fault was entirely in the dock.

... and now those of us who design things with USB-C ports have a very clear market study in "should we shell out the $ to protect the CC pins against a short to VBUS?"

Out of random interest, how would one go to do that? Zener diodes?

TI's solution that they offer in the TPD6S300A is to monitor voltage on the CC pins and cut its connection using a fet if an overvoltage condition is detected.

There were a few specialized IC solutions floating around for this when the max VBUS was at 20V, but now that the 2.1 spec brings it up to almost 50V, it's not clear what the best answer will be.

Zener diodes will burn out mighty quickly if shorted to an actual supply. Would help for a leakage path, but an actual short you need a real solution.

That said, the Switch dock issue is due to poor implementation... not an accidental short.

10C isn't an absurdly fast charge rate if your battery has very low internal resistance. Drone / RC people have been doing that (and more) for years, as their batteries are often made for 50C+ discharge rates.

As a drone guy, 5C charge rate is a bit scary. 2C is reasonable.

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