Delay Lock Loop Initialization Using Propagation Time Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing delay lock loop (DLL) systems in integrated circuit systems face inefficiencies in determining the optimal delay time due to their reliance on incremental adjustments, which can prolong the time required to achieve synchronization between clock and device signals.
Innovation Solution
A test circuit measures the elapsed time between sending a test signal and receiving a response signal, using this measurement to determine an initial delay value for the DLL, which is then incremented or decremented to quickly identify the preferred delay time, thereby reducing the time needed to achieve synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If incremental delay adjustment is used in DLL, then measurement precision of delay time is improved, but time required to determine preferred delay increases
Solution Approach 1:
The patent applies preliminary action by using a test circuit to measure propagation time through the delay circuit before the DLL begins its incremental search. This initial measurement provides a starting point or initial estimate for the delay adjustment, allowing the DLL to begin from a closer approximation of the optimal delay value rather than starting from zero or a fixed default, thereby reducing the number of incremental steps needed to reach the preferred delay.
Solution Approach 2:
The test circuit acts as an intermediary that provides propagation time information to the DLL. This intermediary measurement mechanism bridges the gap between the physical delay characteristics of the circuit and the control logic of the DLL, enabling the system to use this intermediate information to optimize the delay adjustment process and reduce the time required to achieve synchronization.
2Measurement precision
If smaller increment size is used for delay adjustment, then precision of preferred delay is improved, but number of adjustments required increases
Solution Approach 1:
By performing a preliminary propagation time measurement through the delay circuit using the test circuit, the system obtains an initial estimate of the optimal delay value. This allows the DLL to start its adjustment process from a point much closer to the optimal delay, significantly reducing the number of small incremental adjustments needed to achieve the desired precision, thereby improving the speed of determining the preferred delay.
Solution Approach 2:
The patent changes the parameter of delay adjustment by using propagation time measurement to determine an initial delay value rather than starting from a fixed point and using only small fixed increments. This parameter change enables the system to adapt the starting point of the adjustment process based on actual circuit characteristics, reducing the total number of adjustment steps required while maintaining precision.
Data Source
AI summary
Systems and methods for synchronizing communication between devices include using a test circuit to measure a propagation time through a delay circuit. The propagation time is used to determine an initial delay value within a delay lock loop. This delay value is then changed until a preferred delay value, resulting in synchronization, is found. In various embodiments, used of the initial delay value increases the speed, reliability or other beneficial features of the synchronization.