Coarse-Incremental ADC Feedback Correction for Higher Accuracy
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Solution Overview
Problem
Existing analog-to-digital converter (ADC) systems, particularly those combining coarse and incremental ADCs using sigma-delta modulation, face accuracy deficiencies, especially in signal regions where coarse conversion variations occur, leading to numerical errors that affect the overall conversion accuracy.
Innovation Solution
An improved ADC system structure that includes a coarse ADC for determining a digital coarse word and an incremental ADC for determining a digital fine word, with a feedback path and correction block to generate a correction word based on the coarse word and conversion parameters, reducing numerical errors and improving accuracy by iteratively refining the conversion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a combination of coarse ADC and incremental ADC is used, then the conversion accuracy is improved, but numerical errors occur due to feedback from the joint combination
Solution Approach 1:
The patent applies feedback by using the joint combination of coarse and fine conversion results as a feedback signal to the incremental ADC. This feedback mechanism allows the system to iteratively refine the conversion, reducing numerical errors while maintaining improved accuracy. The feedback loop enables the incremental ADC to adjust its conversion based on the coarse conversion result, thereby minimizing the harmful numerical errors that arise from the combination approach.
Solution Approach 2:
The patent introduces an intermediary correction mechanism that processes the joint combination of coarse and fine words. By using an intermediate correction step, the system can identify and compensate for numerical errors before they propagate through the feedback path. This intermediary approach allows the system to maintain the benefits of combined coarse-fine conversion while mitigating the numerical errors that would otherwise degrade accuracy.
2Measurement precision
If the fine conversion is performed iteratively with a predefined number of integration cycles, then the conversion accuracy is improved, but the power consumption increases
Solution Approach 1:
The patent implements partial action by allowing the iterative fine conversion to perform only the necessary number of integration cycles required to achieve the desired accuracy threshold. Rather than always executing a fixed, potentially excessive number of cycles, the system dynamically determines when sufficient accuracy has been reached and terminates the iterative process. This approach maintains high conversion accuracy while significantly reducing power consumption by avoiding unnecessary computational cycles.
3Use of energy by moving object
If the number of integration cycles is reduced to minimize power consumption, then the power consumption is reduced, but the conversion accuracy deteriorates
Solution Approach 1:
The patent uses feedback from the coarse conversion result to guide the iterative fine conversion process. The coarse word provides initial information that reduces the search space for the incremental ADC, allowing it to achieve high accuracy with fewer integration cycles. The feedback mechanism enables the system to adapt the number of cycles dynamically, ensuring that accuracy requirements are met while minimizing power consumption by avoiding excessive iterations.
Solution Approach 2:
The patent performs preliminary coarse conversion before the iterative fine conversion. This preliminary action provides an initial approximation that significantly reduces the complexity and computational requirements of the subsequent fine conversion. By establishing this preliminary result first, the system can achieve the final high-accuracy result with fewer integration cycles, thereby reducing power consumption while maintaining conversion accuracy.
Data Source
AI summary
An ADC system comprises a coarse ADC for determining a coarse word representing an input signal, and an incremental ADC for determining a fine word based on a combination of the input signal and a feedback signal. A first combiner generates a first intermediate output word by joining the coarse word and the fine word. A feedback path generates the feedback signal based on the first intermediate output word. A decimation filter generates a second intermediate output word by filtering the first intermediate output word. A correction block determines a correction word based on the coarse word, on the first and the second predetermined number of bits and conversion parameters of the incremental ADC. A second combiner generates an output word by addition of the second intermediate output word and the correction word.