DAC Cell Weight Calibration Through Composite Reference Outputs
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Solution Overview
Problem
Existing digital-to-analog converters (DACs) face challenges in achieving high accuracy and linearity due to variations in DAC cell weights, which can increase size, cost, and power consumption when using multiple reference cells, and may not be calibrated linearly when reference cells are not adjusted relative to each other.
Innovation Solution
A calibration method for DACs using a single reference cell, where DAC cells are combined and compared to form equations to determine cell error values, allowing for calibration without the need for multiple reference cells, thereby reducing power consumption and processor load while improving linearity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple reference cells are used to calibrate DAC cells, then manufacturing precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent combines multiple DAC cells under test into composite reference cells that serve as reference standards. By merging the functionality of multiple cells and using them collectively as references, the system achieves accurate calibration without requiring separate dedicated reference cells for each DAC cell, thereby reducing device complexity while maintaining manufacturing precision.
Solution Approach 2:
The calibration system uses the DAC cells themselves to generate their own reference values by combining them in specific patterns. The cells under test serve dual purposes: they are both the objects being calibrated and the means by which reference values are generated, eliminating the need for external or separate reference cells and reducing overall device complexity.
2Manufacturing precision
If multiple reference cells are used to calibrate DAC cells, then manufacturing precision is improved, but power consumption increases
Solution Approach 1:
By merging multiple DAC cells into composite reference structures, the system reduces the total number of active reference cells needed. This consolidation decreases the overall power consumption while maintaining the precision benefits that would otherwise require multiple independent reference cells.
Solution Approach 2:
The DAC cells serve multiple functions: they are simultaneously the objects being calibrated and the sources of reference values. This multi-functionality eliminates the need for dedicated reference cells that would consume additional power, as the same cells provide both test and reference functions.
3Manufacturing precision
If DAC cells are calibrated individually against separate reference cells, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent merges multiple DAC cells into composite reference groups that can be used simultaneously for calibration. This allows multiple calibration operations to proceed in parallel or with fewer sequential steps, significantly improving productivity while maintaining the precision that comes from using multiple reference points.
Solution Approach 2:
The system pre-establishes composite reference cells by combining DAC cells in specific configurations before the actual calibration process. This preliminary arrangement of reference values allows for faster calibration execution, as the reference structures are already prepared and can be efficiently utilized during the calibration measurement phase.
4Device complexity
If reference cells are not calibrated relative to each other, then device complexity is reduced, but linearity deteriorates
Solution Approach 1:
By merging DAC cells into composite reference structures, the system inherently establishes relative relationships between the constituent cells. The composite references provide a framework that ensures linearity is maintained across all DAC cells, as the combined structures serve as interconnected reference points that define the linear scale without requiring separate calibration of individual reference cells.
Data Source
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AI summary
A digital-to-analog converter (DAC) calibration system for calibrating NDAC cells in a DAC, where N can be an integer number of DAC cells greater than 2, can include a processor, which can be configured to configure the DAC to generate N reference outputs, configure the DAC to generate N calibration outputs, and determine N overall error values corresponding to a difference between respective individual ones of the N calibration outputs and the N reference outputs. The processor can also be configured to determine, such as using the N overall error values, a cell error value for each of the N DAC cells.