DLL Clock Synchronization with Locked-State Power Control
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Solution Overview
Problem
High-frequency semiconductor devices face challenges in accurately synchronizing internal and external clock signals, leading to performance degradation due to the inability to efficiently manage phase differences and maintain stable locked states in delay-locked loops (DLLs).
Innovation Solution
A clock synchronization circuit incorporating a delay-locked loop (DLL) and a delay-locked control unit that detects and maintains a locked state for a predetermined period, generating a delay-locked disable signal to terminate the delay-locking operation, thereby reducing unnecessary current consumption and improving synchronization accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the delay-locking operation is continuously performed to maintain accurate clock synchronization, then the synchronization accuracy is improved, but the current consumption increases due to continuous operation of the DLL circuit
Solution Approach 1:
The delay-locking operation is performed periodically rather than continuously. The control circuit monitors the locked state of the DLL and terminates the delay-locking operation when the locked state is maintained for a predetermined period of time, thereby reducing current consumption while maintaining synchronization accuracy during active periods
Solution Approach 2:
The DLL circuit automatically maintains its locked state without requiring continuous external control signals. Once locked, the circuit sustains synchronization autonomously, allowing the control circuit to terminate the delay-locking operation and reduce power consumption while the DLL maintains accuracy on its own
2Use of energy by moving object
If the delay-locking operation is terminated early to reduce current consumption, then the energy efficiency is improved, but the synchronization stability deteriorates due to potential phase differences
Solution Approach 1:
The control circuit implements a predetermined time period threshold before terminating the delay-locking operation. This preliminary condition ensures that the DLL has maintained the locked state sufficiently long to establish stable synchronization before power reduction, preventing premature termination that would compromise stability
Solution Approach 2:
The control circuit continuously monitors the locked state of the DLL and uses this feedback to determine when to terminate the delay-locking operation. By baseing the termination decision on actual locked state duration rather than fixed timing, the system ensures synchronization stability is achieved before reducing power consumption
Data Source
AI summary
A clock synchronization circuit includes a delay-locked loop (DLL) and a delay-locked control unit. The DLL is configured to generate an output clock signal by delaying an input clock signal by a delay time, and to execute a delay-locking operation in which the delay time is adjusted to a locked state according to a comparison between the output clock signal and the input clock signal. The delay-locked control unit configured to detect the locked state of the DLL, and to control the DLL based on the determined locked state.