Configurable Clock Tree Delay Matrix Skew Minimization
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Solution Overview
Problem
High-speed data communications interfaces face challenges in managing clock skew between data and clock signals, which limits data transmission rates and reliability, especially in multi-lane links where manufacturers have limited control over connected components.
Innovation Solution
A configurable clock tree with a delay matrix is employed, allowing for selection between different clock signal versions with varying delays to minimize skew between clock and data signals, and between different clock lanes, using multiplexing logic and control signals to optimize clock distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional fixed clock tree is used, then device complexity is reduced, but clock skew between data and clock signals increases, limiting data transmission rates
Solution Approach 1:
The clock tree is made dynamically configurable through a delay matrix that can be programmed to provide different delay values to various clock lanes. This allows the system to adapt clock distribution to match the specific timing requirements of different data lanes, thereby minimizing clock skew and enabling higher data transmission rates without excessive complexity.
Solution Approach 2:
The invention changes the delay parameter of clock signals by using a delay matrix with programmable delay elements. By adjusting the delay values in the matrix, the system can compensate for timing differences between different clock lanes and data lanes, optimizing the timing alignment for high-speed data transmission.
2Reliability
If configurable delay matrix is implemented, then clock skew is minimized, but device complexity increases
Solution Approach 1:
The delay matrix is designed to serve multiple functions: it provides delay adjustment for clock lanes, supports different transmission modes (e.g., alternating polarity mode), and can be configured for various data rates. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in device complexity while achieving precise timing alignment.
3Reliability
If clock skew is not managed, then device complexity remains low, but timing windows for reliable data capture decrease
Solution Approach 1:
The delay matrix is configured in advance to provide the appropriate delay values for each clock lane before data transmission begins. This preliminary configuration ensures that clock signals are properly aligned with their corresponding data lanes from the start, creating sufficient timing windows for reliable data capture without requiring complex real-time adjustment mechanisms.
4Adaptability or versatility
If traditional clock distribution is used, then manufacturing is simpler, but adaptability to different transmission modes is limited
Solution Approach 1:
The clock tree incorporates programmable delay elements that can be configured through software or control logic to adapt to different transmission modes such as alternating polarity mode or traditional mode. This dynamic configurability allows a single hardware design to support multiple transmission modes, providing adaptability without requiring separate dedicated hardware for each mode, thus limiting the increase in manufacturing complexity.
Data Source
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AI summary
System, methods and apparatus are described that facilitate transmission of data, particularly between two devices within an electronic apparatus. A configurable clock tree includes a delay matrix that may be configured such that each the timing of clocks for each of a plurality of data lanes can be optimized for minimum skew. Selections between different versions of a base clock signal and different paths available to the selected version may provide a root clock used for transmitting data on a communications link. The versions of the one or more clock signals may include three versions of a first clock signal. Each version of the first clock signal may be subject to a different delay with respect to the clock signal.