DLL Pattern Injection for Accurate In-Lock Delay Measurement
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Solution Overview
Problem
Existing delay locked loop (DLL) circuits face challenges in accurately measuring delay, which is crucial for phase alignment and operational regulation in electronic devices like memory systems, as current methods may disrupt system environments and lack precision.
Innovation Solution
A DLL circuit and method that includes a delay line, pattern injecting circuit, pattern detecting circuit, and counter, allowing for accurate delay measurement by injecting a predetermined pattern into the reference clock signal and detecting it in the feedback clock signal, even during the locked state, without disrupting the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional delay measurement methods are used, then measurement can be performed, but system environment is disrupted and measurement precision is reduced
Solution Approach 1:
The patent introduces a pattern injecting circuit as an intermediary that inserts a predetermined pattern into the reference clock signal without disrupting the normal clock signal. This pattern serves as a marker that can be detected downstream to measure delay, while the original clock signal continues to operate normally, thus avoiding system environment disruption while enabling precise measurement.
Solution Approach 2:
The patent changes the parameter of the reference clock signal by injecting a predetermined pattern (such as a specific sequence of high/low states) into the clock signal. This pattern injection modifies the signal characteristics temporarily, allowing the measurement circuit to identify the signal's position and calculate delay accurately without affecting the overall system operation.
2Measurement precision
If delay measurement is performed during DLL operation, then real-time delay information is obtained, but measurement timing flexibility is limited
Solution Approach 1:
The patent performs preliminary action by injecting the predetermined pattern into the reference clock signal before the signal passes through the delay line. This allows the measurement system to capture the pattern at a known point in time and compare it with the pattern's position after delay, enabling flexible measurement timing while maintaining real-time accuracy. The pattern injection can be triggered at any appropriate moment without waiting for specific system states.
3Measurement precision
If pattern injection method is used, then delay measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the delay measurement function into distinct modular components: a pattern injecting circuit that inserts markers into the clock signal, a delay line that processes the signal, and a pattern detecting circuit that identifies the markers. This segmentation allows each component to perform its specific function independently, improving measurement accuracy while making the overall system more manageable and maintainable despite the increased complexity.
Data Source
AI summary
A delay locked loop (DLL) circuit that includes a delay line, a pattern injecting circuit, a pattern detecting circuit and a counter is introduced. The delay line may align a phase of a reference clock signal with a phase of a feedback clock signal. The pattern injecting circuit injects a predetermined pattern to the reference clock signal to generate an injected reference clock signal and asserts the injected reference clock signal to the delay line. The pattern detecting circuit detects the predetermined pattern in the feedback clock signal. The counter determines a delay of the delay locked loop circuit according to a first timing when the injected reference clock signal is asserted to the delay line and a second timing when the predetermined pattern is detected in the feedback clock signal. A method of measuring a delay of the DLL circuit is also introduced.