ADC Error Compensation Using DAC Feedback and Gain Correction

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Solution Overview

Problem

Existing signal processing technologies face challenges in accurately converting analog signals to digital signals due to errors in digital-to-analog converter (DAC) circuits, which affect the efficiency and accuracy of signal processing applications.

Innovation Solution

The proposed solution involves an apparatus and method for error compensation in analog-to-digital converters (ADCs) by ascertaining mismatches between DAC circuits and compensating for these mismatches. This is achieved through a compensation circuit that generates feedback signals for each DAC circuit based on the incompatibility between the analog output and digital inputs, applying gains to the digital inputs to correct the output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If DAC circuits are used to convert digital signals to analog signals in ADC systems, then signal conversion functionality is achieved, but errors and mismatches in DAC circuits degrade the accuracy of the converted output signal

Engineering Contradiction:
Improveaccuracy of converted output signalVSAvoiderror in DAC circuit output
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the output of each DAC circuit is fed back through an ADC to measure actual performance, and these measurements are used to generate correction factors that adjust the digital input signals to each DAC, thereby compensating for DAC errors and improving output accuracy

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the parameters of the digital input signals by applying correction factors (gains) to each DAC's input based on measured performance characteristics. This parameter adjustment compensates for mismatches and errors in the DAC circuits, improving the overall accuracy of the analog output signal

Inventive Principle:
Principle #35Parameter changes

2Productivity

If multiple DAC circuits are used to convert different portions of a digital signal, then conversion capacity is increased, but mismatches between individual DAC circuits degrade overall signal accuracy

Engineering Contradiction:
Improvesignal conversion capacityVSAvoidsignal accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by measuring and correcting the performance of each individual DAC circuit separately. Each DAC receives a tailored correction factor based on its specific characteristics, allowing the system to maintain high accuracy across multiple parallel conversion paths while preserving the increased conversion capacity

Inventive Principle:
Principle #3Local quality

3Measurement precision

If feedback signals are generated and gains are applied to correct DAC output errors, then output accuracy is improved, but system complexity increases due to additional compensation circuitry

Engineering Contradiction:
Improveoutput accuracyVSAvoidcompensation circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs the existing ADC circuit to serve multiple functions: its primary function of converting analog input to digital output, and a secondary function of measuring the output of each DAC circuit to generate correction factors. This multi-functionality avoids the need for separate measurement devices, thereby reducing the overall system complexity while still achieving accurate error compensation

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3637619B1Signal processing and conversion
Publication Date: 2025.04.23 NXP USA INC
  • EP3637619B1 patent drawingFigure 1
  • EP3637619B1 patent drawingFigure 2
  • EP3637619B1 patent drawingFigure 3

AI summary

Aspects of the disclosure are directed to compensating for errors in in an analog-to-digital converter circuit (ADC). As may be implemented in accordance with one or more embodiments, an apparatus and/or method involves an ADC that converts an analog signal into a digital signal using an output from a digital-to-analog converter circuit (DAC). A compensation circuit generates a compensation output by, for respective signal portions provided to the DAC, generating a feedback signal based on an incompatibility between the conversion of the signal portions into an analog signal and the value of the signal portions provided to the DAC. A compensation output is generated based on the signal input to the DAC with a gain applied thereto, based on the feedback signal.