Programmable Strobe Clock Generation Using Dual DLL Phase Intervals
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Solution Overview
Problem
Existing solutions for programmable delay strobe generation in timing test and measurement applications require excessive circuit complexity and high manufacturing costs due to the need for numerous delay circuit elements and stringent component matching, which complicates achieving precise timing signals with high resolution without increasing semiconductor real estate.
Innovation Solution
The use of two delay-locked loops (DLLs) with differing numbers of delay elements, synchronized to a common reference clock, allows for the generation of multiple timing signals with various phase relationships, enabling precise timing intervals with fewer components and less critical component tolerances, thus reducing costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single DLL with many delay elements is used to achieve high resolution timing signals, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention divides a single complex DLL into multiple simpler DLLs (typically two or three), each with fewer delay elements. By combining the outputs of these segmented DLLs through logical operations, the system achieves the same high measurement precision as a single large DLL would provide, but with reduced complexity in each individual unit.
Solution Approach 2:
The invention merges the outputs of multiple DLLs with fewer delay elements each to achieve the equivalent functionality of a single DLL with many more delay elements. The combination logic integrates the phase information from multiple sources to generate timing signals with fine resolution, effectively combining simple units to create a complex function.
2Measurement precision
If stringent component matching is used to achieve precise timing signals, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
By segmenting the delay elements across multiple DLLs, each DLL requires fewer delay elements with less stringent matching requirements. The segmentation distributes the precision requirement across multiple components rather than demanding high precision from each individual delay element in a single chain.
Solution Approach 2:
The invention employs feedback mechanisms where the outputs of multiple DLLs are combined and compared, allowing for self-correction and calibration. This feedback approach enables the system to achieve high measurement precision even when individual components have moderate tolerances, as the system can compensate for variations through the combination logic.
3Measurement precision
If many delay circuit elements are used to achieve sufficient performance, then timing signal resolution is improved, but semiconductor real estate increases
Solution Approach 1:
The invention segments the total number of delay elements across multiple DLL units, allowing for more efficient layout and utilization of semiconductor real estate. Each DLL occupies a smaller area, and their combined functionality achieves the same timing resolution as a single large DLL would require, thereby reducing the total area footprint.
Solution Approach 2:
By merging multiple compact DLLs with fewer elements each, the invention achieves high timing resolution without requiring a single large array of delay elements. The combined output of multiple small units provides the same measurement precision as a large unit would, but with better space efficiency and reduced semiconductor real estate requirements.
Data Source
AI summary
Timing test circuits, including programmable strobe and clock generators, may include at least two DLLs having differing numbers of delay elements thereby producing many timing signals having various phase relationships. A detector circuit can generate many different timing intervals as may be defined by independently selected events in signals arising from both of the DLLs.