Alternative power supply for front input
Alternative power supply for front input
The USB connector won't deliver the same power output, so I wouldn't go that route. Instead of wiring it directly, you could wrap the cables and it would work fine. It seems you only need 12 and 5 volts from the existing cables connected to the motherboard. For my HTPCs, I had to modify a 24-pin cable for the remote connection. To avoid altering the PSU wiring, I used short ATX extensions—about 6 inches—and connected the wires there. Would you be able to source the required wires from that location or another PSU port?
Consider using a dual rail power source and crafting your own adapter cable. Keep in mind that yellow represents 12V and red stands for 5V. You'll still have to supply AC to the power unit, making this option less appealing compared to connecting the PC's 12V/5V directly.
Where exactly are you sourcing that 2A rating? It usually isn't from any USB A port on a motherboard. Those typically max out between 0.5 to 0.9 A, depending on the model. It seems they're just indicating the maximum it can manage, maybe with a phone charger or another source.
It should probably provide more power than your PC motherboard, though you’ll need to verify your surge protector guidelines. The main concern is whether the connector with both 5V and 12V in on your IO panel works—your USB-to-SATA adapter only supports 5V, so the extra 12V isn’t required unless it’s for a specific device.
You're unsure about the voltage details, as most sources mention 5V. The USB rating you found refers to current, not voltage. It's possible the numbers are mixed up.
SATA power also delivers 12V. It seems the 12V is required to supply 9V for QC3.0.