Time-Interleaved ADC Clock Correction for Sampling Mismatch
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Solution Overview
Problem
Time-interleaved analog-to-digital converters (ADCs) face performance degradation due to mismatched sampling instants, which are affected by temperature and other factors, and existing solutions have been ineffective in providing reliable alignment.
Innovation Solution
A system comprising a first and second ADC, a correction circuit with delay and multiplier circuits to generate error signals, and a clocking circuit that uses these signals to produce corrected clocking signals for maintaining proper timing alignment between the ADCs, ensuring sampling instants are separated by half the clock period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time-interleaved ADCs are used to double the sampling speed, then the productivity is improved, but the reliability deteriorates due to sampling instant mismatch and performance degradation
Solution Approach 1:
The patent implements a feedback mechanism where the sampling instant mismatch is detected and used to generate correction signals that adjust the clock phases. The system continuously monitors the mismatch between ADC sampling instants and applies corrective feedback to maintain proper timing alignment, thereby resolving the reliability issue while preserving the high-speed advantage of time-interleaved architecture.
Solution Approach 2:
The patent dynamically adjusts the clock signal parameters (phase and timing) based on detected sampling instant mismatches. By changing the clock phase parameters in response to measured errors, the system compensates for timing deviations caused by temperature and other factors, maintaining reliable operation at doubled sampling speeds.
2Device complexity
If conventional correction approaches are used, then the device complexity is reduced, but the reliability remains ineffective due to inability to compensate for temperature and timing variations
Solution Approach 1:
The patent replaces complex mechanical or hardware-based timing adjustment mechanisms with an electronic signal processing approach. Instead of physically adjusting clock routes or using complex delay lines, the invention uses digital signal processing to detect timing errors and generate correction signals, achieving high reliability with reduced hardware complexity.
Solution Approach 2:
The patent introduces an intermediary correction signal that mediates between the detected timing mismatch and the clock generation system. This intermediary error signal serves as a bridge, translating timing deviations into actionable correction commands that adjust the clock phases without requiring direct complex interaction between the ADCs and clock sources.
3Productivity
If sampling instants are separated by 180 degrees for time-interleaved operation, then the productivity is improved, but the manufacturing precision deteriorates as maintaining exact phase matching becomes difficult due to temperature and other factors
Solution Approach 1:
The patent transitions from a static fixed-phase clocking system to a dynamic adaptive system. The clock phases are no longer fixed at manufacturing but are dynamically adjusted during operation based on real-time detection of sampling instant mismatches. This dynamic approach allows the system to maintain 180-degree separation for high-speed operation while automatically compensating for phase drift caused by temperature and manufacturing variations.
Solution Approach 2:
The patent performs preliminary detection and correction of timing mismatches before they significantly degrade performance. By continuously monitoring sampling instants and applying corrections in advance, the system prevents accumulation of timing errors that would otherwise require complex manufacturing precision to avoid.
Data Source
AI summary
A time-interleaved analog-to-digital converter (ADC) is provided. The ADC generally comprises a first ADC, a second ADC, correction circuit, a divider, and a clocking circuit. The first ADC receives an analog input signal and generates a first output and a differentiated output. The second ADC receives the analog input signal and generates a second output. The correction circuit receives the first output, the second output, and the differentiated output and generates a first error signal and a second error signal. The divider receives the first error signal and the second error signal and generates a timing error by dividing the second error signal by the first error signal, and the clocking circuit receives a clock signal and the timing error and generates a plurality of corrected clocking signals, where each of the first and second ADCs receives at least one of the clocking signals.