Differential Slew Rate Control Using Eye Crossing Feedback
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Solution Overview
Problem
Existing slew rate control systems require complex circuits and adjustable voltage or current sources to change slew rates, which is inefficient and cumbersome.
Innovation Solution
A slew rate control device comprising a signal generation circuit, a comparator circuit, and a control circuit that generates differential signals and adjusts their slew rates based on the relative positional relationship between an eye crossing point and a reference clock edge, using phase interpolators with switches and current sources to control the slew rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional slew rate control methods are used with adjustable voltage or current sources, then the slew rate can be changed, but the circuit complexity increases and the system becomes cumbersome
Solution Approach 1:
The patent replaces traditional mechanical/physical adjustable voltage or current sources with a digital control mechanism. The control circuit generates digital control signals that directly switch between different slew rate states, eliminating the need for complex analog adjustment components and reducing overall circuit complexity while maintaining slew rate adaptability
Solution Approach 2:
The patent changes the control parameter from continuous analog voltage/current adjustment to discrete digital control signals. By using digital signals to select between predefined slew rate states, the system achieves adaptability without requiring complex continuous adjustment mechanisms, thereby reducing device complexity
2Manufacturing precision
If complex circuits are used for slew rate detection and control, then the slew rate can be controlled, but the ease of operation deteriorates
Solution Approach 1:
The control circuit automatically detects the eye crossing point position relative to the reference clock edge and self-adjusts the slew rate without requiring external intervention. The system monitors its own performance and makes corrections autonomously, simplifying operation while maintaining precise control through the automatic feedback mechanism
3Adaptability or versatility
If adjustable voltage or current sources are provided for slew rate control, then the slew rate can be changed, but the device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the complex adjustable voltage or current source components from the slew rate control system. Instead, it uses a simplified digital control circuit that switches between fixed slew rate states, achieving variability without the need for complex continuous adjustment sources, thereby reducing both device complexity and cost
Data Source
AI summary
A slew rate control device and a slew rate control method are provided. The slew rate control device includes a signal generating circuit, a comparator circuit, and a control circuit. The signal generating circuit generates a first voltage signal and a second voltage signal having a slew rate, and the first voltage signal and the second voltage signal are a pair of differential signals. The comparator circuit outputs an enabling signal according to a relative positional relationship between an eye crossing point of the pair of differential signals and a signal edge of a reference clock. The control circuit generates at least one control signal according to the enabling signal to control the signal generating circuit, such that the signal generating circuit changes the slew rate of the first voltage signal and the second voltage signal according to the at least one control signal.