USB-PD Thema. What is responsible for generating different voltages at VBUS? Is it not the CCGX chip, right? If a UFP needs 20V and negotiates with CCGX chip, then how is 20V at VBUS generated? How does CCGx chip "says" to power system that "please make 20V at VBUS"?
I hope you understand the question.
The CCGx will control a Buck or Buck-Boost converter for generating the required VBUS voltage after the PD negotiation.
The buck-boost converter can be controlled by the CCGx through select lines or through I2C depending on the type of converter.
Please refer to the hardware files in CCG3 Evaluation Kits.