Programmable Delay Circuit for Fractional Clock Alignment
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Solution Overview
Problem
Synchronous circuits face challenges in aligning data and clock signals due to different propagation delays, which limits their operational speed and timing margins.
Innovation Solution
A programmable delay circuit that provides integer and fractional time resolution, allowing for precise delay matching of clock signals with data signals, utilizing a series of delay circuits and NAND gates to achieve time alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data and clock signals are not time aligned due to different propagation delays, then the synchronous circuit can operate, but the operational speed is limited and timing margins are reduced
Solution Approach 1:
The delay circuit is segmented into multiple delay units (first delay unit, second delay unit, third delay unit) that can be independently controlled. Each delay unit introduces a specific delay amount, allowing the total delay to be precisely adjusted to match propagation delays and optimize timing alignment between data and clock signals.
Solution Approach 2:
The delay circuit provides dynamically adjustable delay through control signals that enable or disable specific delay units. This dynamic adjustment capability allows the system to adapt to different propagation delay conditions and optimize timing margins under varying operational conditions.
2Reliability
If a delay circuit is added to time align data and clock signals, then timing margins are improved, but the device complexity increases
Solution Approach 1:
The delay circuit is divided into modular delay units that can be independently controlled. This segmentation allows for precise delay adjustment while maintaining a relatively simple overall structure, as each unit performs a specific function and can be enabled or disabled based on timing requirements.
Solution Approach 2:
The delay circuit serves multiple functions: it provides timing alignment between data and clock signals, adjusts for different propagation delays, and can be dynamically reconfigured for different operational modes. This multi-functionality reduces the need for separate circuits for different timing adjustments.
3Productivity
If the column control circuit operates without optimal timing adjustment, then the circuit structure remains simple, but the bus occupation rate and data throughput are reduced
Solution Approach 1:
The timing control system uses dynamic delay adjustment through control signals that can enable or disable specific delay units based on operational requirements. This dynamic control allows the system to optimize bus occupation rate and data throughput without requiring a completely complex control architecture.
Solution Approach 2:
The system optimizes performance by changing the delay parameter introduced by the delay circuit. By adjusting the delay amount through different control signal combinations, the system can achieve optimal timing for maximum bus occupation rate and data throughput without fundamentally changing the circuit structure.
Data Source
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AI summary
A programmable delay circuit capable of providing a delay with integer and fractional time resolution is described. In one exemplary design, an apparatus includes first and second (500) delay circuits. The first delay circuit provides a first delay of an integer number of time units. The second delay circuit (500) couples to the first delay circuit and provides a second delay of a fraction of one time unit. The first delay circuit may include multiple unit delay cells coupled in series. Each unit delay cell may provide a delay of one time unit when enabled. The second delay circuit (500) may have first and second paths. The first path may provide a shorter delay when selected, and the second path may provide a longer delay when selected. The second path may be coupled to at least one dummy logic gate (518) that provides extra loading to obtain the longer delay for the second path.