USB Power Delivery Vendor Defined Message Tunneling
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Solution Overview
Problem
There is a risk of unsafe charging when using a power adapter not manufactured by the computer's manufacturer, as it may not provide reliable power delivery, and existing technologies lack effective methods to authenticate and manage power allocation securely across USB Power Delivery interfaces.
Innovation Solution
The system employs an embedded controller in the computer to tunnel commands through a USB Power Delivery interface to a power adapter, using vendor-defined messages and GPIO pins to authenticate and manage power allocation, ensuring safe and reliable charging by decoupling USB PD controllers from transaction details and allowing flexible communication protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a power adapter not manufactured by the computer's manufacturer is used, then device compatibility and user choice are improved, but charging safety and reliability deteriorate
Solution Approach 1:
The system performs authentication and power capability negotiation before actual power delivery begins. The computer PD controller and adapter PD controller exchange messages to verify identities and determine safe power levels in advance, preventing unsafe charging before it can occur.
Solution Approach 2:
The authentication and power negotiation process uses bidirectional communication where both the computer PD controller and adapter PD controller exchange capability information and verification responses. This feedback mechanism ensures both parties confirm compatibility and safety before power transfer.
2Adaptability or versatility
If USB Power Delivery interface is used for power negotiation, then power allocation flexibility is improved, but security risks from untrusted adapters increase
Solution Approach 1:
Authentication occurs before power allocation. The system verifies the identity and trustworthiness of the adapter through a challenge-response mechanism using cryptographic keys stored in secure elements, ensuring security is established before any power negotiation takes place.
Solution Approach 2:
Secure elements act as intermediaries that store cryptographic keys and perform authentication operations. These secure elements mediate between the USB PD controllers and the power delivery process, providing a trusted layer that verifies adapter authenticity before allowing power negotiation.
3Adaptability or versatility
If vendor-defined messages are tunneled through USB PD interface, then communication flexibility with slave devices is improved, but protocol complexity increases
Solution Approach 1:
The USB PD communication interface serves multiple functions: it performs standard power negotiation, authentication, and also tunnels vendor-defined messages to communicate with slave devices. This multi-functionality reduces the need for separate communication channels while maintaining flexibility.
Solution Approach 2:
The USB PD controllers act as intermediaries that translate and tunnel vendor-defined messages between the host system and slave devices through the power delivery interface. This mediation allows existing USB PD infrastructure to carry additional communication protocols without requiring completely separate communication channels.
Data Source
AI summary
An electronic system includes a computer and a power adapter. The computer includes an embedded controller (EC) coupled to a computer power delivery (PD) controller. The power adapter includes a power adapter PD controller connected to a slave device and is configured to communicate with the computer over a communication link. The computer PD controller is configured to receive a command from the EC and, to transmit a universal serial bus (USB) vendor defined message (VDM) header and one or more vendor defined objects (VDOs) including the information of the payload of the transmit command. The power adapter PD controller responds to the one or more VDOs either by changing an output signal to the slave device connected to the power adapter PD controller, reports a state of a general purpose input/output (GPIO) pin of the power adapter PD controller, or changes the state of the GPIO pin.