Thank you for posting on the Intel® communities.
I would like to inform you that the Internal Power Supply connector of the board is mainly used as an alternative way to power the board, it works as an Input power connector as you can see in the Technical Product Specifications.
Therefore, the internal connector can't be used to power an external device.
I hope that the information provided answers to your question. If you need further assistance please let us know.
Intel Technical Support Technician