ADC Self-Measurement Circuit for DAC Capacitance Mismatch Correction
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Solution Overview
Problem
Conventional methods for measuring D/A conversion units in delta-sigma analog-to-digital converters (ADCs) require additional circuit components, increasing design complexity and hardware cost, which complicates the correction of mismatch errors among multiple D/A conversion units.
Innovation Solution
An analog-to-digital converter (ADC) with a dual operation mode that includes an input path selection module and a processing circuit, allowing for the measurement of capacitance ratios between D/A conversion units without significant additional circuit components, thereby correcting mismatch errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional circuit components are introduced to measure the relative sizes between multiple D/A conversion units, then the mismatch errors can be corrected, but the design difficulty and hardware cost increase
Solution Approach 1:
The ADC is designed to perform both A/D conversion and measurement functions using the same core circuit components. The input path selection module enables the ADC to switch between conversion mode and measurement mode, allowing the same hardware to serve multiple purposes without requiring separate dedicated measurement circuits.
Solution Approach 2:
The ADC uses itself to measure the relative sizes of D/A conversion units. By configuring the input path selection module to connect D/A unit inputs to reference voltage terminals instead of the analog signal input, the ADC performs self-diagnosis and self-characterization, eliminating the need for external measurement equipment.
2Manufacturing precision
If additional circuit components are introduced to measure the relative sizes between multiple D/A conversion units, then the mismatch errors can be corrected, but the hardware cost increases
Solution Approach 1:
The ADC is designed to perform both A/D conversion and measurement functions using the same core circuit components. The input path selection module enables the ADC to switch between conversion mode and measurement mode, allowing the same hardware to serve multiple purposes without requiring separate dedicated measurement circuits.
Solution Approach 2:
The ADC uses itself to measure the relative sizes of D/A conversion units. By configuring the input path selection module to connect D/A unit inputs to reference voltage terminals instead of the analog signal input, the ADC performs self-diagnosis and self-characterization, eliminating the need for external measurement equipment.
3Manufacturing precision
If the ADC operates in measurement mode to measure capacitance ratios, then the mismatch errors can be corrected, but the A/D conversion operation may be affected
Solution Approach 1:
The ADC dynamically switches between A/D conversion operation mode and measurement operation mode through the input path selection module. This dynamic reconfiguration allows the system to adapt its function based on operational needs, performing measurements when calibration is required and normal conversion during operational phases.
Solution Approach 2:
The measurement operation can be performed periodically or on-demand to update the capacitance ratio information for correction purposes. The system alternates between normal A/D conversion operations and measurement/calibration operations, ensuring that correction data is current without continuously disrupting the primary conversion function.
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
The solution enables accurate measurement and correction of mismatch errors among D/A conversion units, enhancing the performance of the ADC while minimizing the impact on the A/D conversion operation mode.
Implementation Method 1
the input path selection module couples the unit input terminal of a D/A conversion unit to be measured among the plurality of D/A conversion units to a first reference voltage, and couples the unit input terminals of the other D/A conversion units among the plurality of D/A conversion units to a second reference voltage
Implementation Method 2
the plurality of D/A conversion units generates an output signal according to the unit input terminals of the plurality of D/A conversion units
Data Source
AI summary
The present application discloses an ADC (10). The ADC has an A/D conversion operation mode and a measurement operation mode. The ADC includes an input terminal (100), a DAC (104), and an output terminal (102). The input terminal is configured to receive an analog signal. The output terminal is configured to output a digital signal. The DAC includes a plurality of D/A conversion units. When the ADC operates in the A/D conversion operation mode, the ADC is configured to convert the analog signal into the digital signal, and when the ADC operates in the measurement operation mode, the digital signal related to a ratio of a capacitance of the D/A conversion unit to be measured to a total capacitance of the plurality of D/A conversion units.