Predictive Level-Crossing ADC Circuit for Lower Comparison Power
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Solution Overview
Problem
The power consumption of analog-to-digital converters (ADCs), particularly in level-crossing ADCs, is high due to frequent comparisons of the input signal with reference signals, which is not aligned with the reduced power consumption in semiconductors, and there is a need for a more power-efficient solution.
Innovation Solution
A predictive level-crossing ADC method and circuit that adjusts threshold levels based on previous level crossings, reducing comparisons by using one threshold level when no crossing occurs and alternating between threshold levels to track sparse signals efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent comparisons of input signal with reference signals are performed in level-crossing ADC, then signal conversion accuracy is maintained, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by predicting future threshold levels based on current and past signal values before actual comparisons occur. The predictor circuit pre-calculates which threshold level will be appropriate for the next comparison, allowing the system to skip unnecessary comparisons and directly compare with the predicted threshold, thereby reducing power consumption while maintaining accuracy
Solution Approach 2:
The patent implements partial action by performing comparisons only when necessary - specifically, only when the input signal is expected to cross a threshold level. Instead of continuously comparing with all possible threshold levels, the system selectively performs comparisons based on predicted signal behavior, reducing the total number of comparisons by up to 50% while maintaining adequate measurement precision
2Use of energy by moving object
If the number of comparisons is decreased to reduce power consumption, then power efficiency improves, but signal tracking accuracy may deteriorate
Solution Approach 1:
The patent uses feedback mechanisms where the output of each comparison is fed back to the predictor circuit, which uses this information along with past signal values to refine its predictions of future threshold levels. This feedback loop ensures that even with fewer comparisons, the system adapts to actual signal behavior and maintains accurate tracking by continuously improving its prediction accuracy based on observed crossing patterns
Solution Approach 2:
The predictor circuit performs self-service by autonomously determining the optimal threshold level for comparison based on historical signal data and current conditions. The system serves itself by internally predicting and selecting the appropriate reference threshold without requiring external control or continuous full-scan comparisons, thereby reducing power consumption while maintaining autonomous accurate signal tracking
Data Source
AI summary
A method for predictive level-crossing, LC, in an analog-to-digital converter, ADC, is provided. The method comprises the steps of comparing a first input signal sampled during a first sampling period with one of an upper threshold level and a lower threshold level to determine if a level crossing has occurred during said first sampling period. Which one of said two threshold levels that is compared with said first input signal is based on if a level crossing occurred during a prior sampling period directly prior to the first sampling period, and which one of the two threshold levels was compared to a prior input signal sampled during said prior sampling period.