USB PD Source

USB C all the things!
Like many hobbyists, I find myself regularly hanging on to old laptop/DC power supplies. On one hand I've always planned on using them for something, on the other, I've been trying to minimize my e-waste.
So, I designed this! Using a screw terminal or a DC barrel jack as an input, and a USB C connector as an output, we can power modern devices that take advantage of the USB C Power Delivery specification. From phones to laptops, USB C should be the connector of the future!

USB PD can negotiate 5-20V at up to a current of 5A. This means a max power of 100w!
I've chosen to design a board that contains a buck converter capable of a 100% duty cycle. This means that any power supply capable of 19.5 - 36V will allow generation of all possible PDOs.

By default the device is configured to negotiate 5 preconfigured PDOs:
- 20V @ 5A
- 15V @ 5A
- 12V @ 5A
- 9V @ 5A
- 5V @ 5A

However, these can easily be adjusted using an I2C programming interface, as well as 0603 strapping resistors.

This board features:
- 8A Buck Converter with 100% max duty cycle
- LED indication of input power, output power, and negotiated voltage
- DC barrel jack or screw terminal input rated at 8A
- I2C solder points with pullup resistors
- GPIO solder points indicating contract negotiation
- 3.3V LDO