3D Die Stacking Data Bit Alignment via Delay Lines
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Solution Overview
Problem
In 3D integrated circuits, the mismatch in timing of multiple data bits arriving at a sampling device leads to errors in data reading due to the reduction or elimination of the combined 'eye opening' time, causing performance degradation and potential system failure.
Innovation Solution
A system and method using digitally-controlled delay lines (DCDLs) and phase detection arrays to align multiple data bits by determining the relative timing of each bit and adjusting the delay to ensure that all bits are sampled within their respective 'eye opening' times, thereby maintaining accurate data reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple data bits are read simultaneously on the same clock pulse in 3D integrated circuits, then data throughput increases, but timing mismatch between chips reduces the effective 'eye opening' time and causes reading errors
Solution Approach 1:
The patent applies preliminary action by measuring the arrival time of each data bit at the sampling device before the actual sampling operation. The system determines the first-to-arrive and last-to-arrive bits in advance, then uses this information to adjust delay lines so that all bits are properly aligned during the sampling clock pulse. This preliminary timing measurement and adjustment ensures that the effective eye opening is maximized before data reading occurs, thereby maintaining high reliability while enabling simultaneous multi-bit throughput.
2Measurement precision
If the reading clock pulse is aligned with the center of the 'eye opening' for a single bit, then that bit is read correctly, but other bits arriving at different times may be misread
Solution Approach 1:
The patent applies dynamics by making the delay line adjustments dynamic and adaptive based on actual bit arrival times. Rather than using a fixed clock alignment, the system continuously measures which bits arrive first and last, then dynamically adjusts the delay lines to equalize arrival times. This dynamic adaptation allows the system to maintain precise timing alignment for all bits simultaneously, enabling accurate multi-bit reading while preserving the benefits of simultaneous sampling.
3Reliability
If delay lines are adjusted to align bit arrival times, then all bits can be sampled within their eye opening times, but the system complexity increases
Solution Approach 1:
The patent applies feedback by using the measured arrival time information to control the delay line adjustments. The system measures which bits arrive first and last, feeds this information back to the delay line control logic, and uses it to adjust the delay amounts accordingly. This feedback mechanism ensures that delay lines are optimally configured based on actual timing conditions, maintaining high reading accuracy while using a relatively simple control structure that adapts to varying timing scenarios.
Data Source
AI summary
Systems and methods are disclosed for aligning multiple data bits by adjusting the timing of input lines for those data bits. Embodiments include a hierarchical structure for comparing the timing of multiple sets of bits. Other embodiments include aligning data bits from multiple chips in a 3D die stacking architecture.