We used this all last year: https://www.amazon.com/RioRand-Conve...dp/B071H39ZN5/
Wire in 12VDC from the PDP, attach a multimeter to the output pins on the regulator, twist the potentiometer until you get roughly 19V (the dev board doesn't actually need this high a voltage, pretty sure it's on board regulators can take down to 12V). The wire up a barrel jack that can plug into the TX1. You'll want to mount it on your robot in a way that ensures it cannot contact other electrical components or metal (3d print a case, Velcro on back, double side tape on back, etc).
Note the one we used was not from this seller, and there are plenty of comparable boost converters that will work in this application from alternate sites (eBay, AliExpress, etc)
Try to stay toward higher current ratings as the advertised specs aren't always accurate on these cheapy boost converters, and the tegra can draw a few amps if I remember correctly. Take a look at the AC adapter it came with for the current rating. If I remember correctly our application didn't break 2A at ~19VDC, but power usage will be completely dependant on what your vision code is doing.