Not 100% what you want, but I have this thing that works great. USB powered POE injector.

If you only plug in 1 USB you don't get the full 15 watts, but for low powered devices it works fine. Bigger devices, you use both USB connectors.

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https://www.amazon.com/gp/product/B00PZ02AA8/ref=ppx\_yo\_dt\_b\_search\_asin\_title?ie=UTF8&psc=1