Adaptive Hold-Time Clock Delay for Accurate Data Sampling
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Solution Overview
Problem
Setting the appropriate hold time in digital circuits is challenging, as insufficient hold time can lead to erroneous data capture, while excessive hold time prolongs setup and cycle times, decreasing circuit speed.
Innovation Solution
A hold-time optimization circuit that includes a delay control circuit and a correction circuit, where the delay time of the clock signal is adjusted based on a correction pulse signal generated from the transition edges of the data and clock signals, using a glitch generation circuit and voltage-controlled or digitally-controlled delay mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hold time is increased to ensure accurate data capture, then the reliability is improved, but the setup time and cycle time are prolonged, decreasing the circuit speed
Solution Approach 1:
The patent applies dynamics by making the hold time adjustable rather than fixed. The delay control circuit dynamically modifies the hold time based on operational requirements, allowing the system to optimize between reliability and speed depending on the specific operating conditions. This is achieved through the delay element that can vary its delay amount under control of the control signal.
Solution Approach 2:
The patent changes the parameter of hold time from a fixed value to a variable value that can be adjusted via the control signal. By modifying the delay amount of the delay element based on control signals, the system can adapt the hold time parameter to achieve optimal performance for different operating modes, resolving the contradiction between reliability and speed.
2Productivity
If the hold time is decreased to improve circuit speed, then the productivity is improved, but the digital circuit may capture data in erroneous cycles, worsening the reliability
Solution Approach 1:
The system dynamically adjusts the hold time based on control signals, enabling the circuit to operate at higher speeds when conditions permit while maintaining sufficient hold time for reliable data capture. The delay element's variable delay characteristic allows the system to optimize productivity without sacrificing reliability.
Solution Approach 2:
By changing the hold time parameter from fixed to variable through the delay control circuit, the system can reduce hold time to improve productivity when appropriate, while ensuring reliability is maintained through controlled adjustment based on operational requirements signaled by the control signal.
3Device complexity
If a fixed hold time is used to simplify the circuit design, then the device complexity is reduced, but the circuit cannot adapt to different operating conditions, worsening the adaptability
Solution Approach 1:
The patent introduces a delay control circuit that adds dynamic capability to the hold time adjustment. This controlled variability allows the circuit to adapt to different operating conditions while maintaining a relatively simple overall structure. The control signal mechanism provides adaptability without requiring complex redesign.
Solution Approach 2:
By implementing a controlled parameter change mechanism for the hold time, the circuit gains adaptability to different operating conditions. The delay element's ability to vary its delay amount under control allows the system to adjust to different scenarios while keeping the added complexity minimal through the use of a control signal approach.
Data Source
AI summary
A hold-time optimization circuit includes a correction circuit and a delay control circuit. The delay control circuit delays a clock signal for a delay time so as to generate a delay clock signal. The correction circuit generates a correction pulse signal according to transition edges of a data signal and transition edges of the delay clock signal. The delay time of the delay control circuit is optimized according to the correction pulse signal. The data signal is sampled according to the delay clock signal.