DLL Harmonic State Detection Using Delayed Clock Edge Comparison
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Solution Overview
Problem
Existing delay-locked loops (DLLs) face challenges in detecting and correcting harmonic states, which can occur when the sum of delay elements' delays correspond to multiples of the input reference signal period, leading to undesirable operating conditions.
Innovation Solution
A detector apparatus and method for detecting harmonic states in DLLs by comparing delayed clock signals from at least two delay elements, using D flip-flops to evaluate rising edges, and adjusting delay times through a regulating device to transition the DLL back to a basic state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sum of delay elements' delays corresponds to multiples of the input reference signal period, then the DLL enters a harmonic state, but this leads to undesirable operating conditions
Solution Approach 1:
The detector apparatus proactively monitors the delay times of delay elements before the harmonic state fully develops. By detecting when the sum of delay times approaches a multiple of the reference signal period, the system can take preventive action (adjusting delay times) before the harmful harmonic operating condition is established, thus maintaining reliability while avoiding the harmful state.
Solution Approach 2:
The detector apparatus continuously monitors the delay times of delay elements and provides feedback signals to the controlling device. This feedback mechanism enables real-time detection of harmonic states by comparing the sum of delay times against the reference signal period, allowing the system to dynamically adjust and eliminate harmonic conditions, thereby resolving the contradiction between maintaining delay configurations and avoiding harmful harmonic states.
2Reliability
If delay times of delay elements are adjusted to correct harmonic states, then the DLL transitions back to basic state, but this requires additional detection and control mechanisms
Solution Approach 1:
The detector apparatus is designed to perform multiple functions: it monitors delay times, detects harmonic states, and generates control signals for correction. By integrating these functions into a single multi-functional device, the patent reduces overall system complexity while maintaining the ability to detect and correct harmonic states, thus resolving the contradiction between state stability and device complexity.
Solution Approach 2:
The detector apparatus automatically monitors and detects harmonic states without requiring external intervention. Once a harmonic state is detected, the system self-corrects by adjusting the delay times through the controlling device, eliminating the need for complex external detection and control mechanisms. This self-service approach maintains state stability while minimizing added complexity.
Data Source
AI summary
Detection of harmonic states in a delay-locked loop. A plurality of delayed clock signals within the delay-locked loop is evaluated and, on the basis thereof, in particular on the basis of the time points of the rising edges in the delayed clock signals, it is ascertained whether a harmonic state has arisen in the delay-locked loop.