Self-Calibrating Current Sensor Using Dual-Range Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional current sensors face challenges in achieving accurate measurements due to linearity drift and environmental factors, with open-loop sensors being cost-effective but prone to recalibration issues, and closed-loop or fluxgate sensors being more accurate but costly and complex.
Innovation Solution
A self-calibrating current measuring apparatus comprising a low-range and high-range current sensor, where the low-range sensor (closed-loop or fluxgate) provides calibration data to the high-range sensor (open-loop) to correct for linearity drift, using a self-calibration circuit to generate and apply calibration data based on voltage signal comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If open-loop current sensors are used for cost-effective measurements, then device cost is reduced, but measurement precision deteriorates due to linearity drift
Solution Approach 1:
The current sensor system is segmented into two independent sensor channels: a first current sensor (open-loop, cost-effective) and a second current sensor (closed-loop or fluxgate, high-precision). Each sensor operates independently to measure the same current, allowing the system to benefit from both low cost and high accuracy without requiring a complete redesign of the sensing architecture.
Solution Approach 2:
A self-calibration circuit acts as an intermediary between the two sensor channels, processing their respective output signals. This circuit compares the signals, determines calibration parameters, and applies corrections to reconcile the measurements from both sensors, thereby transferring the precision advantage of the second sensor to the overall system output.
2Measurement precision
If closed-loop or fluxgate current sensors are used for accurate measurements, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system segments the sensing function across two different sensor types rather than using a single complex sensor. The first sensor (simpler open-loop design) handles cost-effective measurement, while the second sensor (more complex closed-loop or fluxgate) provides calibration reference. This segmentation allows the complex sensor to be used only for calibration purposes rather than continuous measurement.
Solution Approach 2:
The system implements self-calibration functionality where the calibration process is performed automatically by the self-calibration circuit using the outputs from both sensors. This eliminates the need for external calibration equipment or manual intervention, reducing operational complexity while maintaining high measurement precision through continuous self-correction.
3Device complexity
If conventional current sensors are used without self-calibration, then device complexity is reduced, but measurement precision deteriorates due to linearity drift
Solution Approach 1:
The self-calibration circuit enables the sensor system to perform its own calibration automatically by comparing outputs from two sensor channels and generating calibration parameters. This self-service capability maintains high measurement precision without requiring external calibration equipment or complex manual calibration procedures, achieving a balance between automated precision maintenance and acceptable system complexity.
Data Source
AI summary
A self-calibrating current measuring apparatus comprising a low-range current sensor configured to generate first voltage signals, a high-range current sensor configured to generate second voltage signals, and a self-calibration current measuring circuit configured to: receive the first voltage signals and the second voltage signals, convert the first voltage signals and the second voltage signals into respective first digital signals and second digital signals, compare the first digital signals with the second digital signals, determine a difference between the first digital signals and the second digital signals exceed a recalibration threshold based on the comparison, generate calibration data based on the determination, and generate a digital output signal representative of a current reading based on an application of the calibration data to the second digital signals.