Really now?
USB 2.0 has the same power output as USB 1.0 and does not support fast charging.
From wikipedia. If the port on the device only supports 2.0, how does it handle the extra power input to allow fast charging? And what devices have a USB-C port that isn’t using the 3.2 standard?
It’s a little complicated. A USB-3 connection must provide higher current 900mA than a USB-2 connection 500mA. As such a USB-3 data connection can charge faster than a USB-2 connection - some people may call this “fast charging”.
However USB-PD (Power Delivery, aka fast charging) was released as part of the USB 3.1 specification, but it does not require a USB-3 data connection and neither does a USB-3 data connection require USB-PD. You can see all the different USB-C modes on Wikipedia as well, where USB-2 and Power Delivery are listed separately: https://en.wikipedia.org/wiki/USB-C#USB-C_receptacle_pin_usage_in_different_modes
That’s the part you are missing. Modern charging doesn’t use standard USB power. That’s the whole fast charging landscape is addressing.
Read this https://www.androidcentral.com/qualcomm-quick-charge
The power brick can supply more than 5 V over a standard USB port because it’s not adhering to USB standards for supplying power. As a result, data and power are decoupled, allowing the power brick to supply more than a standard USB port over a connector and cable which are identical to USB ports and cables.
