Time-Interleaved ADC Timing Skew Detection and Compensation
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Solution Overview
Problem
Multi-channel time-interleaved analog-to-digital converters face significant challenges in achieving exact matching of sampling times across channels, leading to timing skew errors that severely affect dynamic performance, especially due to process deviations and environmental changes.
Innovation Solution
The proposed solution involves a multi-channel time-interleaved analog-to-digital converter architecture that includes a clock generation circuit, channel mismatch parameter detection circuit, signal compensation and reconstruction circuit, and energy detector, utilizing notch filters, mismatch error discriminators, alpha filters, and adaptive iterative circuits to detect and correct timing skew errors, allowing for accurate calculation and compensation of timing skew errors, even when individual channel sampling frequencies do not meet the Nyquist criterion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple ADC channels are connected in parallel with staggered clocks to achieve high-speed conversion, then the sampling rate increases in direct proportion to the quantity of interleaved parallel ADC channels, but timing skew errors occur due to process deviations and environmental changes
Solution Approach 1:
The patent implements a feedback mechanism by detecting timing skew errors through mismatch error discriminators and using adaptive iterative circuits to calculate correction values. The detected timing skew information is fed back to adjust the sampling clocks of individual ADC channels, creating a closed-loop system that continuously compensates for timing deviations and maintains synchronization accuracy.
Solution Approach 2:
The patent dynamically adjusts the sampling clock parameters (phase and timing) of individual ADC channels based on detected timing skew errors. By changing the clock parameters adaptively rather than maintaining fixed timing, the system compensates for process deviations and environmental changes, allowing the ADC channels to operate with corrected timing relationships.
2Reliability
If timing skew errors are corrected using foreground or background correction technologies, then dynamic performance of the Time-interleaved ADC is improved, but the device complexity increases due to additional detection and correction circuits
Solution Approach 1:
The patent divides the timing skew correction function into separate modular components: mismatch error discriminators for detecting errors, adaptive iterative circuits for calculating correction values, and separate clock adjustment mechanisms for each ADC channel. This segmentation allows each component to perform a specific function independently, making the overall correction system more manageable and less complex than a monolithic approach.
Solution Approach 2:
The patent implements self-service by enabling the ADC system to automatically detect its own timing skew errors and generate correction values without external intervention. The mismatch error discriminators monitor the system's own performance, and the adaptive iterative circuits autonomously calculate and apply corrections, allowing the system to self-diagnose and self-correct timing issues.
3Ease of manufacture
If individual ADC channels operate at low frequency, then each ADC can be designed with simpler circuitry, but the equivalent sampling frequency must meet the Nyquist criterion requiring precise timing synchronization
Solution Approach 1:
The patent applies dynamics by making the sampling clock frequencies and phases of individual ADC channels adjustable rather than fixed. The adaptive iterative circuits dynamically modify the clock parameters based on real-time timing skew detection, allowing the system to adapt to varying conditions and maintain precise effective sampling frequency even though individual channels operate at lower, simpler frequencies.
Data Source
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AI summary
The present invention provides a multi-channel time-interleaved analog-to-digital converter, where the multi-channel time-interleaved analog-to-digital converter includes: a clock generation circuit, configured to generate a work clock of the analog-to-digital converter; a channel ADC group, including M ADC channels, arranged to be in a time-interleaved architecture, and configured to convert, under the control of the clock generation circuit and in a time division multiplexing manner, one high-speed analog input signal into M low-speed digital output signals, where M is an integer not less than 2; a channel mismatch detection circuit, configured to detect in real time timing skew errors of output signals of the M ADC channels, to obtain a timing skew parameter of each ADC channel relative to a reference ADC channel; a signal compensation and reconstruction circuit, configured to perform, according to the timing skew parameters detected by the channel mismatch detection circuit, compensation and reconstruction on the digital output signals output by the channel ADC group; and a signal combining circuit, configured to combine the M low-speed output signals that are of the channels and generated after the compensation by the signal compensation and reconstruction circuit, to obtain one final high-speed digital output signal.