Time-Interleaved ADC Timing Calibration for Skew Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed analog-to-digital conversion circuits face data distortion due to time skewing errors, which are difficult to correct, especially for higher frequency signals using existing auto-correlation methods.
Innovation Solution
An analog-to-digital conversion circuit employing a timing calibration circuit that calculates correlation values and adjusts the phase of a clock signal applied to ADCs based on differences in correlation values, effectively correcting timing skew errors during high-speed conversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple ADCs are used in time-interleaving configuration to achieve high-speed conversion, then conversion speed is improved, but time skewing errors occur between ADCs causing data distortion
Solution Approach 1:
The system divides the high-speed conversion task into multiple parallel ADC channels operating in time-interleaved fashion, where each ADC handles a portion of the sampling process. This segmentation enables high-speed conversion while the patent subsequently applies calibration techniques to correct the timing skew introduced by this segmented approach.
Solution Approach 2:
The patent applies parameter changes by adjusting the phase of clock signals applied to individual ADCs based on calculated time skew errors. The timing calibration circuit dynamically modifies clock phase parameters to compensate for timing mismatches, thereby maintaining data accuracy despite the segmented parallel architecture.
2Measurement precision
If auto-correlation operation is used to correct time skew error, then timing calibration is achieved, but the method is unsuitable for higher frequency signals
Solution Approach 1:
The patent implements a feedback mechanism where the timing calibration circuit continuously monitors timing skew errors and adjusts clock phases accordingly. This closed-loop feedback approach enables effective calibration for high-frequency signals by dynamically adapting to timing variations that occur at higher frequencies, overcoming the limitations of open-loop auto-correlation methods.
3Reliability
If timing calibration circuit dynamically adjusts clock phase to correct time skew, then data distortion is reduced, but circuit complexity increases
Solution Approach 1:
The timing calibration circuit is designed to perform multiple functions: it calculates time skew errors, determines phase adjustment amounts, and controls clock signal phases for multiple ADCs. This multi-functional design consolidates what could be separate complex circuits into a single integrated unit, reducing overall system complexity while maintaining signal integrity.
Data Source
AI summary
An analog-to-digital conversion circuit includes; a first analog-to-digital converter (ADC), a second ADC and a third ADC collectively configured to perform conversion operations according to a time-interleaving technique, and a timing calibration circuit configured to calculate correlation values and determine differences between the correlation values using first samples generated by the first ADC, second samples generated by the second ADC, and third samples generated by the third ADC during sampling periods, wherein the timing calibration circuit is further configured to control a phase of a clock signal applied to the second ADC in response to a change in absolute value related to the differences generated during the sampling periods.