Trezor Model T voltage and electric current tolerance

General topics About Trezor
1

the “Create wipe code to erase device” article (trezor. io/learn/a/create-wipe-code-to-erase-device) highlights that the Trezor Model T can be powered by sources other than a computer:

The Trezor Model T does not have to be connected to any kind of host interface to use the wipe code. You can wipe your device by entering the wipe code after powering the device with a power bank, USB in your car, or a socket on your bedroom wall.

the nominal voltage and its range varies across USB specifications (USB hardware - Wikipedia). what is the range of tolerance of voltage for the Model T?

also, can it affect the hardware negatively if the device is plugged into a port that can provide a high electric current?

2

not as long as the port doesn’t actually provide that high current :))

To-spec USB-C ports and chargers are safe, they’ll provide the baseline power until the device actively asks for more. I would be wary of plugging Trezor into things like, I dunno, charger for your RC car, that just happens to have a USB-C plug but is not actually USB-C.

I don’t have the exact numbers but Trezor should be OK with a power source that is at least vaguely in the USB spec tolerance.

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3

here is an actual answer:

TT uses https://www.torexsemi.com/products/single-type-voltage-regulators/series/?name=xc6210 which has operating voltage up to 6.0V
T1 uses https://www.microchip.com/en-us/product/MCP1703 which has operating voltage up to 16.0V

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4

thank you matejcik!

so non-standard sources (e.g. an RC car charger) are capable of disregarding the current the device is asking for and just force feed it with whatever they were programmed for? if they can, what would be the maximum current that is safe to use from an unregulated port? I didn’t find that information in the XC6210’s data sheet.

5

I’m not an electrical engineer and I strongly suspect that this is an electrical engineering question. There is relation between voltage and current, and from my high school physics understanding I suspect that you can’t actually “push” too much current given the same voltage, because the actual current at a fixed voltage only depends on Trezor’s resistance. My guess would be the excess power would be dissipated at the charger’s voltage regulator.

What the charger would usually do is provide unsafe voltage resulting in a higher current.

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