I found this step up converter that might work, if it fits. The adapter's jack is 5.5mm x 2.1mm. I'm not sure if the barrel jack dimensions are right for the Mighty, though, since I'm at work.

You will need a 12V supply for the left connector. I've never used one, but this looks like it might be what you need to connect to USB. Otherwise there are little boost converters out there that would work.

The right connector is for the photodiode which you only need if you want some sort of information about the illumination level outside the camera, it is usually used to control an IR Cut filter.

I got this step up converter on Sunday.

It's a partial success. It works on half of the USB 3 ports that I tried it on, and it worked with an Anker PowerPort 2 charger. For my needs, that is sufficient. Ymmv.