Electrical – USB-C as a high current power source

usbusb device

I'd like to power up a PCB that I'm design with USB-C. The main reasoning is that the connector is low-profile, reversible and can carry 5A at 5V. This PCB will have an ATmega2560 chip onboard, which will be programmed via USB.

What do I need to take into consideration to do the following:

1) Power the PCB via USB-C, providing 5A (where possible)

2) Use the USB-C to program the chip

Does some sort of negotiation need to be done between the sink (my PCB) and source (wall transformer)? Alternatively, can I just read the necessary voltage on one of the CC pins? Also I only need to use the D+ and D- lines of the USB-C as I only need to run at USB2 speeds.

As an aside, this similar question mentions:

Keep in mind that a typical Type-C receptacle needs a thin PCB (0.8 mm), which is fairly inconvenient for DIY projects

I can't see any mention of that in data sheets I've seen. Any further info?

Best Answer

With USB Type C the power can be up to 3A @ 5V without any negotiation. To go beyond that (up to 5A @ 20V) requires negotiation over the CC lines. There are USB type C connectors that work with a 0.062 board such as Wurth 632723300011.

Here is a good article on USB Power I found:

https://www.digikey.com/en/articles/techzone/2017/mar/designing-in-usb-type-c-and-using-power-delivery-for-rapid-charging