Isolating usb pd? Difficulties doing usb pd in a test equipment

[gmariz]

Hello!

Recently I started a project with the intention of turning it into a comercial product, more specifically a 10A micro-ohmmeter with decent capabilities. Problem is, for continuous measurement operation it draws at most 20W (ouch!) which would make it so that, for charger only (power could be buffered by the battery) use, it would need a decently large power input. The idea then, so that I would not need to certify any mains operation, was to use usb-pd for charging at 20W.

The real problem came with complying to the isolation and protection requirements that come with having the usb port by the iec61010 standard. My first instinct is to isolate the usb port with a flyback converter but no transformers seem to be able to handle the isolation + power requirements that I need. Am I missing something really obvious or is this impossible with off the shelf parts?