Delay Lock Loop Initial Delay Compensation for Clock Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuits (ICs) face issues with clock signal stability due to manufacturing processes and temperature variations, leading to normal operation failures.
Innovation Solution
A delay lock loop comprising a delay unit, an elimination unit, a phase detection unit, and a control unit, which adjusts the delay factor to synchronize clock signals, reducing initial delays and minimizing component count, thereby increasing usable space and reducing consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional delay lock loop is used to delay clock signals, then the delay function is achieved, but an initial delay cannot be eliminated and more components are required
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the initial delay value of the delay unit in a register before the delay lock loop operation begins. This initial delay characterization is performed once during manufacturing or initialization, and the stored value is then used to compensate for the initial delay during normal operation, eliminating the need for additional components while achieving accurate delay cancellation
Solution Approach 2:
The patent changes the delay parameter dynamically by adjusting the delay factor based on the stored initial delay value. The control unit modifies the delay unit's delay factor using the pre-characterized initial delay information, allowing the system to compensate for initial delay through parameter adjustment rather than adding more hardware components
2Reliability
If more components are added to eliminate initial delay, then delay accuracy is improved, but usable space decreases and consumption increases
Solution Approach 1:
The patent makes the existing delay unit serve multiple functions: it provides both the intended delay function and the initial delay cancellation function. By characterizing and storing the initial delay value in a register and using the same delay unit with adjusted delay factor, the system eliminates initial delay without requiring separate cancellation components, thus preserving usable space while improving clock signal stability
Solution Approach 2:
The delay unit characterizes its own initial delay and uses this self-measured information to compensate for its own imperfections. The system measures the initial delay of the delay unit, stores it, and then uses this information to adjust the delay factor, allowing the delay unit to self-correct its initial delay error without external intervention or additional components
3Reliability
If the delay factor is adjusted to eliminate initial delay, then clock signal synchronization is improved, but control complexity increases
Solution Approach 1:
The patent performs preliminary characterization of the delay unit's initial delay and stores this value in a register before normal operation. This pre-computed initial delay value simplifies the control mechanism during operation, as the control unit only needs to add this stored value to the delay factor adjustment, rather than implementing complex real-time measurement and control circuits
Solution Approach 2:
The patent implements a feedback mechanism where the phase detection unit monitors the phase difference between clock signals and feeds this information back to the control unit. The control unit then adjusts the delay factor based on both the feedback signal and the pre-stored initial delay value, creating a closed-loop system that achieves accurate phase synchronization through relatively simple control logic
Data Source
AI summary
A delay lock loop is provided. A delay unit includes a delay factor and delays a first clock signal to generate a second clock signal according to the delay factor. An elimination unit delays a third clock signal to generate a fourth clock signal. A phase detection unit is coupled to the delay unit and the elimination unit and generates an indication signal according to a phase difference between the second and fourth clock signals. A control unit is coupled to the phase detection unit and the delay unit. The control unit controls the delay unit according to the indication signal to adjust the delay factor. When the delay factor is equal to an initial value, an initial time difference occurs between the first and second clock signals. A time difference between the third and fourth clock signals is equal to the initial time difference.