Time-Interleaved ADC Clock Synchronization Without Global Reset
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Solution Overview
Problem
Synchronization of sampling clock signals between distributed groups of unit ADCs in massively time-interleaved ADCs is challenging, and synchronization errors are difficult to detect and correct, leading to performance degradation due to misalignment of sampling windows across Process-Voltage-Temperature-Extraction (PVTE) corners.
Innovation Solution
An autonomous synchronization architecture utilizing a multi-group multiple input multiple output phase interpolator (MG-MIMO-PI) and an adaptation engine to synchronize inter-group and intra-group ADC clocks without relying on global reset signals, employing foreground and background calibration schemes to align clock and token signals, and adapt to ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a large number of unit ADCs are connected to support higher speed communications, then the ADC operating speed increases, but synchronization of sampling clock signals between distributed groups becomes more difficult and errors are harder to detect
Solution Approach 1:
The system divides the large number of unit ADCs into multiple distributed groups, with each group having its own autonomous synchronization mechanism. This segmentation allows each group to maintain synchronization independently, reducing the complexity of global synchronization across all ADCs while enabling higher overall operating speeds.
Solution Approach 2:
The patent implements feedback mechanisms where each ADC group monitors its own synchronization status and automatically adjusts its sampling clock signals. The system detects synchronization errors within each group and provides corrective feedback to maintain alignment, ensuring reliable synchronization even as the number of unit ADCs increases.
2Device complexity
If traditional global reset signals are used for synchronization, then the architecture is simpler, but the system cannot adapt to ambient conditions and synchronization errors cannot be corrected on-the-fly
Solution Approach 1:
The system transitions from static global reset signals to dynamic autonomous synchronization where each ADC group can adapt its timing in real-time. The synchronization architecture allows continuous adjustment of sampling clock signals based on detected errors and ambient conditions, providing both adaptability and maintainable complexity through modular design.
Solution Approach 2:
Each ADC group is equipped with autonomous synchronization capabilities that allow it to self-correct timing errors without external intervention. The groups independently detect synchronization errors and adjust their own clock signals, eliminating the need for complex global control while adapting to changing ambient conditions.
3Adaptability or versatility
If sampling windows are not precisely synchronized across PVTE corners, then the system is more tolerant of manufacturing variations, but performance degrades due to misalignment
Solution Approach 1:
The system dynamically changes timing parameters of sampling clock signals to maintain precise synchronization across PVTE corners. Each ADC group adjusts its clock signal characteristics (phase, frequency, timing offsets) based on detected synchronization errors, ensuring manufacturing precision is maintained despite process-voltage-temperature variations.
Data Source
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AI summary
An apparatus includes a first phase interpolator configured to receive a first clock signal and generate a second clock signal, and an ADC (105) that includes a clock divider (110, 235) configured to generate a third clock signals based on the second clock signal, a token generator (110, 235) configured to generate a first token signal, a first phase detector (1000A) configured to generate a first and second output based on the first and third clock signals, and a second phase detector (1000B) configured to generate a third output based on the token signal. Control logic may be provided to perform a foreground calibration to align the first token signal with a second token signal of a second ADC-group (105a-105k), and a background calibration to align the third clock signal with the first clock signal.