Flip-Flop Transition Detection for Faster Set-Up Timing
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Solution Overview
Problem
Existing signal value storage circuitry, such as D-type flip-flops, face significant performance penalties due to increased set-up time requirements for error detection and correction, which are exacerbated by process variations and voltage fluctuations, leading to inefficiencies in data processing systems.
Innovation Solution
The integration of transition detector circuitry downstream of the storage circuitry, along with delay and tristate inverter circuitry, allows for direct monitoring of signal transitions within the storage circuitry during error detection periods, reducing uncertainty and enabling smaller margins, thus improving set-up times and operational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transition detector circuitry is placed upstream to monitor the input of the master latch, then late arriving signals can be detected, but the set-up time increases significantly due to the need for timing margins
Solution Approach 1:
Instead of placing the transition detector upstream at the master latch input (conventional approach), the patent inverts the approach by placing the transition detector downstream at the slave latch input. This inversion allows detection of transitions that occur during the error detection period without requiring additional timing margins at the critical master latch setup time, thereby resolving the contradiction between error detection capability and set-up time penalty.
2Reliability
If timing margins are increased to guarantee detection across process, temperature, and voltage variations, then reliability improves, but set-up time increases significantly
Solution Approach 1:
The patent introduces an intermediary error detection period controlled by dedicated control logic that operates independently from the critical data path timing. This intermediary mechanism allows the system to detect transitions under varying process, temperature, and voltage conditions without imposing timing penalties on the main data path, thus resolving the contradiction between detection reliability and set-up time.
3Productivity
If operating frequency is increased to improve productivity, then errors occur more frequently, but the overhead for error recovery is less than the gain achieved
Solution Approach 1:
The system performs self-diagnosis by automatically detecting transitions during the error detection period and triggering error recovery operations without external intervention. This self-service capability enables the system to operate at higher frequencies with increased error rates, as the error detection and recovery overhead is minimized through automated operation, resolving the contradiction between productivity and reliability.
Data Source
AI summary
A D-type flip-flop includes tristate inverter circuitry passing a processing signal through to storage circuitry 8 from where the processing signal passes via a transmission gate to slave storage circuitry. A transition detector is coupled to the input node of the storage circuitry and serves to generate an error signal if a transition is detected upon that input node during an error detecting period. Other forms of this technique may provide clock gating circuitry.