How does STUSB4500 handle a USB Power Delivery 3.1 Source PDO?

[johnsondavies]

I've written an STUSB4500-based MCU application that displays the voltage and current options available from a USB-C adapter, and allows you to select one.

New chargers that support USB Power Delivery 3.1 can offer Source PDOs above 20V. For example, the Apple 140W charger offers a Source PDO of 28V 5A.

Do I need to filter out a PDO greater than 20V before using it to set up a Sink PDO on the STUSB4500, or is this done automatically by the STUSB4500? I'm concerned that a 28V VBUS would damage the STUSB4500 and surrounding circuitry.

[johnsondavies]

By experimenting I've confirmed that the STUSB4500 automatically filters out USB Power Delivery 3.1 Source PDOs above 20V, and PPS profiles, so your application doesn't need to do that. Here's the application I've developed based on the STUSB4500:

Power Deliverer

[johnsondavies]

Also, does anyone know where I can buy one or two STUSB4500 QFN-24 chips?

[Winfred LU]

It is done automatically by STUSB4500.

During negotiation, STUSB4500 will try to find a best match (to some Source PDO) according to its own PDO settings.

The Source PDOs above 20V simply do not match.