Clock Distribution Timing Control With Phase Interpolators
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Solution Overview
Problem
As data transmission rates increase, ensuring that digital signals from electronic devices like memory devices and testers are transmitted at the proper time and in synchronism becomes challenging due to unequal signal path lengths and variations in propagation delays caused by process, voltage, and temperature changes, making it difficult to control the timing of DQ signals relative to DQS and DQS* signals.
Innovation Solution
A system with first and second signal distribution trees, each equipped with phase interpolators and delay lines, adjusts the timing of digital input signals to ensure synchronized output across multiple branches, compensating for variations in propagation delays and maintaining precise timing relationships between DQ and DQS signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data transmission rate is increased, then productivity is improved, but timing synchronization of digital signals deteriorates
Solution Approach 1:
The patent divides the clock distribution system into multiple independent clock trees, each serving specific pin groups. This segmentation allows independent optimization and timing control for different signal groups, enabling high-speed transmission while maintaining synchronization precision for each segment.
Solution Approach 2:
The patent implements dynamic timing adjustment through phase interpolators and delay lines that can adaptively compensate for timing variations. These dynamic elements allow the system to maintain synchronization precision even as transmission rates increase and cause greater timing skew.
2Manufacturing precision
If signal path length is made equal across all branches, then timing synchronization is improved, but device complexity increases
Solution Approach 1:
The patent introduces phase interpolators and delay lines as intermediary elements in the clock distribution path. These intermediaries actively compensate for path length differences without requiring all physical paths to be equal, thereby maintaining timing synchronization while accepting unequal signal path lengths.
Solution Approach 2:
The patent changes the timing parameters of clock signals dynamically using phase interpolators that can adjust phase shifts. This allows the system to compensate for path length variations by changing signal parameters rather than constraining physical path lengths to be equal.
3Manufacturing precision
If propagation delay variations are compensated, then timing precision is improved, but use of energy increases
Solution Approach 1:
The patent performs preliminary timing compensation by pre-calculating and pre-adjusting phase shifts and delay values before data transmission begins. This preliminary action reduces the need for continuous active compensation during operation, thereby reducing overall energy consumption while maintaining timing precision.
Data Source
AI summary
The timing of output signals can be controlled by coupling a digital signal through a signal distribution tree having a plurality of branches extending from an input node to respective clock inputs of a plurality of latches. A phase interpolator is included in a signal path common to all of the branches, and a respective delay line is included in each of the branches. Each of the latches couples a signal applied to its data input to an output terminal responsive to a transition of the digital signal applied to its clock input. The delay lines are adjusted so that the latches are simultaneously clocked. The delay of the phase interpolator is adjusted so that the signals are coupled to the output terminals of the latches with a predetermined timing relationship relative to signals coupled to output terminals of a second signal distribution tree.