Hi all
I want to make a device just like USB type-C audio dongle, and which can play the music via phone and charge the phone simultaneously.
For USB audio DAC, I have candidate parts in my mind, but I don't know how to choose type-C chips.

There are type-C controllers in the market, however, their functions are changing between DFP & DFP.
As far as I know, if I put a type-C controller in the dongle, then:
* If UFP, power direction is dongle to phone. Dongle as USB host, phone as USB device.
* If DFP, all directions listed above are reversed.

I need a chip which can make a phone identifies itself as a USB host, and at the same time, the phone can be charged. I teardown some dongles and find that there is type-C PD controller inside. I am curious what makes the phone as a USB host and can be charged simultaneously, with a PD controller.

 

I've only done a little with USB so I'm not an expert, but read up on the USB bus protocols and charging. There is some negotiation that happens to determine the capabilities of the devices on the bus. Understanding those parts will make it easier for you to choose the best hardware for your needs. This would be a good starting point for an overview before digging into the details: https://en.wikipedia.org/wiki/USB