Virtual Ground Compensation for USB-PD Communication Stability
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Solution Overview
Problem
High current power transfer through USB-PD can cause significant ground shifts between devices, leading to communication disruptions or disconnections, which existing methods like using larger copper wires or shorter cables cannot effectively address without increased costs and limited flexibility.
Innovation Solution
A communication device with a converter circuit that provides a virtual device ground to compensate for potential differences between the host and communication devices, using a buck converter and compensator to maintain a stable connection, independent of the host device's implementation, allowing for flexible and cost-effective solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If larger copper wire diameters or shorter cable lengths are used to minimize ohmic resistance, then ground potential difference is reduced, but cost increases and wiring flexibility is limited
Solution Approach 1:
The patent introduces a virtual ground as an intermediary reference potential that mediates between the host device ground and the communication device ground. This virtual ground, generated by the converter circuit, allows communication signals to be referenced to a stable potential without requiring low-impedance physical ground connections, thus resolving the contradiction between communication reliability and wiring flexibility
Solution Approach 2:
The patent replaces the mechanical/electrical solution of using thicker wires or shorter cables with an electronic solution - a converter circuit that generates a virtual ground. This substitution eliminates the need for physical ground optimization while maintaining communication stability under high current conditions
2Power
If USB-PD allows up to 100 W of electrical power per port, then power transfer capability is enhanced, but ground shift between devices increases causing communication failures
Solution Approach 1:
The virtual ground acts as a mediator that isolates the communication circuitry from the high-current power transfer effects. By providing a stable reference potential that is not directly coupled to the power ground, the converter circuit enables high power transfer (up to 100W) without the ground shifts that would otherwise disrupt communication
Solution Approach 2:
The patent segments the ground system into multiple domains: the power ground for high-current transfer and the virtual ground for communication reference. This segmentation allows each domain to operate independently - the power ground handles high currents while the virtual ground maintains stable communication references, resolving the contradiction between power capability and communication reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The virtual device ground ensures stable communication by compensating for ground shifts, preventing disconnections and allowing higher power transfer without the need for costly physical changes in wiring, thus enhancing communication reliability and flexibility.
Implementation Method 1
a converter circuit, which converter circuit is configured to provide a virtual device ground at least to the device controller to compensate a ground potential difference between the host device and the communication device
Data Source
AI summary
A communication device for connection with a power source and a host device is provided. The communication device comprises a device controller and a converter circuit. The device controller is adapted for data communication with the host device and the converter circuit is configured to provide a virtual device ground at least to the device controller, so as to compensate a ground potential difference between the host device and the communication device.