Control Signal Delay Circuit for Setup and Hold Timing
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Solution Overview
Problem
As clock frequencies increase, the setup and hold times in flip-flops become a larger portion of the clock cycle, leaving less time for input data to change state without violating timing requirements, making it challenging to correctly latch signals relative to clock edges.
Innovation Solution
The proposed solution involves a circuit with series-coupled delay buffers and logic gates that assess and adjust the delay of control signals relative to clock signals, using flip-flops and registers to determine suitable delay values, ensuring that signals are latched correctly without violating setup and hold timing margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If clock frequency is increased, then productivity is improved, but setup and hold times represent a larger portion of the clock cycle, reducing the time available for input data to change state
Solution Approach 1:
The patent applies preliminary action by measuring and determining the appropriate delay value before the actual data latching operation. The delay assessment circuit evaluates setup and hold timing margins in advance, allowing the system to pre-calculate the optimal delay value that will ensure correct timing compliance when the high-frequency clock operates, thus resolving the contradiction between high productivity and sufficient time for data changes
2Productivity
If clock frequency is increased, then productivity is improved, but setup and hold times become a larger portion of the clock cycle, making it more difficult to meet timing requirements
Solution Approach 1:
The patent implements feedback through the delay assessment circuit that continuously monitors setup and hold timing margins. The circuit measures the actual timing relationships between clock edges and control signals, feeds this information back to determine the appropriate delay value, and adjusts the delay accordingly to maintain reliable timing compliance even at increased clock frequencies
Solution Approach 2:
The patent applies dynamics by making the delay value adjustable and adaptive rather than fixed. The delay assessment circuit dynamically determines the appropriate delay based on actual timing conditions, allowing the system to adapt to varying clock frequencies and timing requirements, thus maintaining reliability while enabling higher productivity
3Measurement precision
If delay assessment circuit is implemented, then measurement precision of timing margins is improved, but device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a dedicated delay assessment circuit that acts as a mediator between the clock signal and the data latching operation. This specialized circuit precisely measures setup and hold timing margins without significantly complicating the overall system, as it performs a specific function (timing measurement) that enables accurate delay determination
Data Source
AI summary
A circuit includes a plurality of series-coupled delay buffers and a plurality of logic gates. Each logic gate includes first and second inputs. The first input of each logic gate is coupled to a corresponding one of the delay buffers. The circuit also includes a plurality of flip-flops. Each flip-flop includes a data input and a data output. The data input is coupled to an output of a corresponding one of the logic gates and the data output is coupled to the second input of one of the corresponding logic gates.