USB Controller Electrical Termination Control via Single Signal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing USB communication systems face complexity in implementing the required electrical termination for USB controllers operating in dual-role modes, which complicates control logic and circuit board layout due to inadequate adherence to USB specification.
Innovation Solution
The implementation of termination circuits controlled by a single control signal (HOST_SEL) that dynamically switches between pull-up and pull-down resistors to provide appropriate electrical termination for USB Type-C connectors, allowing the USB controller to operate in both host and device modes without additional control signals, thereby simplifying the logic and reducing the number of circuit elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate control signals are used for pull-up and pull-down termination circuits, then electrical termination compliance is achieved, but device complexity and control logic increase
Solution Approach 1:
The patent combines the control of pull-up and pull-down termination circuits into a single control signal (HOST_SEL). When HOST_SEL is high, the pull-up termination is enabled; when HOST_SEL is low, the pull-down termination is enabled. This merging of control functions reduces the number of control signals from two to one, simplifying the control logic while maintaining proper electrical termination for both USB host and device modes.
Solution Approach 2:
The single HOST_SEL control signal serves multiple functions: it simultaneously controls both the pull-up termination circuit and the pull-down termination circuit. This multi-functionality allows one signal to manage the electrical termination state for different USB operational modes (host and device), reducing overall system complexity while ensuring specification compliance.
2Manufacturing precision
If multiple control signals are used for termination control, then precise electrical termination is achieved, but the number of pins and circuit elements increases
Solution Approach 1:
The patent merges the control functions for pull-up and pull-down termination into a single HOST_SEL control signal. This reduces the number of control pins required from two to one, and consequently reduces the number of circuit elements needed for signal distribution and control logic, while maintaining precise electrical termination through the complementary activation of pull-up and pull-down circuits.
3Adaptability or versatility
If dual-role USB controller operates in both host and device modes, then operational flexibility is improved, but electrical termination control becomes more complex
Solution Approach 1:
The HOST_SEL control signal provides universal control for both USB host and device mode operations. In host mode, HOST_SEL high enables pull-up termination; in device mode, HOST_SEL low enables pull-down termination. This single multi-functional control mechanism manages the electrical termination requirements for both operational roles, maintaining adaptability while reducing control complexity.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Some embodiments include apparatuses and methods having a node to couple to a serial bus, and a controller to provide a control signal to one of a first circuit path and a second circuit path in order to change electrical termination of a signal at the node between a first electrical termination through the first circuit path during a first mode of the controller and a second electrical termination through the second circuit path during a second mode of the controller. The controller can be arranged to provide the control signal to the first and second circuit paths during the first and second modes without providing another control signal from the controller to the first and second circuit paths during the first and second modes.