SAR ADC Capacitor Calibration for Reference Ripple Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of successive approximation analog-to-digital converters (SAR ADC) in wireless electronic communication systems leads to errors in comparison results due to changes in reference voltage caused by the extraction of electrical charge, resulting in incorrect comparison outcomes.
Innovation Solution
An analog-to-digital converting device comprising a comparator, digital-to-analog converters with capacitors, and a reference buffer, where the capacitors' capacitance is adjusted based on ripple signals generated by changes in the reference voltage, allowing for accurate calculation and compensation of errors introduced by voltage ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the SAR ADC extracts electrical charge from the reference buffer, then the conversion operation can be performed, but the reference voltage changes causing comparison errors
Solution Approach 1:
The patent implements a feedback mechanism where the ripple signal from the reference buffer is detected and used to adjust the capacitor values in the DAC. The system measures the actual voltage ripple caused by charge extraction and uses this information to compensate for the reference voltage changes, thereby maintaining comparison accuracy despite continuous conversion operations.
Solution Approach 2:
The patent dynamically adjusts the capacitance values of the capacitors in the digital-to-analog converter based on the detected ripple signal. By changing the capacitor parameters in response to the reference voltage variations, the system compensates for the voltage drops caused by charge extraction, ensuring accurate comparisons throughout the conversion process.
2Measurement precision
If the capacitance of capacitors is adjusted to compensate for voltage ripple, then comparison accuracy improves, but device complexity increases
Solution Approach 1:
The system performs self-calibration by automatically detecting its own ripple signal and using this information to adjust its own capacitor values. The ADC system serves itself by measuring the reference buffer ripple and autonomously compensating for it through capacitor adjustment, eliminating the need for external calibration equipment or complex control systems.
Solution Approach 2:
The patent combines the ripple detection function and the capacitor adjustment function into the existing ADC structure. The same comparator and control logic that perform the main conversion function are also used to detect the ripple and control the capacitor adjustments, merging multiple functions into existing components rather than adding separate dedicated circuits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables accurate error calculation and compensation of capacitance in the analog-to-digital converting device, improving the accuracy of comparison results by addressing the voltage ripple-induced errors in SAR ADC systems.
Implementation Method 1
the at least one digital to analog convertor comprises at least one capacitor... a first ripple signal is generated according to a change of a voltage of the reference signal
Data Source
AI summary
An analog to digital converting module includes a comparator, at least one digital to analog convertor, and a reference buffer. The comparator is configured to compare a first input signal and a second input signal so as to output a comparing signal. The at least one at least one digital to analog convertor includes at least one capacitor. The reference buffer is configured to provide a reference signal. The at least one digital to analog convertor receives the reference signal such that a ripple signal is generated according to a change of a voltage of the reference signal. The capacitance of the capacitor of the at least one digital to analog convertor is adjusted based on the ripple signal.