Question with the Switch and Charging

[LinktheDeme]

Okay so the nintendo switch has both a 5.0V-1.5A and a 15V-2.6A.

I was wondering if someone more electronic savy can explain how this works?

My understanding is that with Amps the device will only draw as much as it's capable of so there's no real concern with that.

However with Volts you can cause some serious issues on underpowering or overpowering.

I'm wondering how the charger can draw either a 5V or a 15V. And what would happen if I sent it through 5V but a higher amp like a battery pack that has a 2.4 at 5V?

[Deejay]

I'm pretty sure that means that the Switch can draw up to 15v. The wall brick outputs 15v, but most portable chargers are 5v. If you have the switch connected to a 5v charger while in use, the battery will still drain but at a lesser rate than if it weren't plugged in to anything.

I learned this watching a switch accessories review on youtube so take it with a grain of salt.

[Niya]

Since the switch has a type C USB charger it can use the power delivery mode/negotiation specified with USB 3.x (not sure it if was 3.1 or already 3.0).
PD means the charger and device negotiate what modes each of them supports and select the highest possible supported by both. Through PD the voltage can AFAIK be raised up to 20V.
All chargers that support PD have to start with 5V and wait for negotiation signals, so a "normal" USB device that doesn't support higher modes can't be fried.

And for the amp values. Even "dumb" USB devices can tell the charger how much they support at max, and some other stuff like cable quality is also factored in, so the charger only outputs what the device requests. This process can fail if either side doesn't play by the rules, that's why 3rd party phone chargers are sometimes way slower than the original one even though they support high-amp modes.

This whole signalling/negotiation system is the reason why the switch is so picky with 3rd party chargers. Many type C chargers support PD modes, but if they don't offer a 15V mode nego will fail and it has to fall back to the highest-amp 5V mode.

[LinktheDeme]

Thanks!