Self-Calibrating IC Current Sensor for Divider Configurations
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Solution Overview
Problem
Current sensors with integrated current conductors face limitations in measuring high currents due to physical and thermal constraints, leading to reduced resolution and variability in current division when using a current divider configuration, requiring complex calibration methods or costly assembly processes.
Innovation Solution
An integrated circuit current sensor with a self-calibration feature, including an integrated current conductor, magnetic field transducer, controllable gain stage, and calibration controller, allows for adjustable gain to match the output signal to a predetermined voltage level, enabling accurate measurement of total current without user-intensive calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current divider configuration is used to measure high currents, then the current sensor's over-current capability is improved, but the resolution and measurement precision deteriorate due to reduced current through the integrated current conductor
Solution Approach 1:
The patent implements a calibration controller that measures the actual current division ratio and uses feedback to adjust the output signal accordingly. The controller monitors the relationship between the shunt current and integrated current conductor current, then applies compensation to maintain measurement precision despite the current division configuration.
Solution Approach 2:
The patent changes the electrical parameters (gain, offset) of the output signal based on the measured current division ratio. By adjusting these parameters through calibration, the system compensates for the reduced current through the integrated current conductor, thereby maintaining resolution and measurement precision while operating in a current divider configuration.
2Measurement precision
If manual calibration methods are used to compensate for manufacturing tolerances, then measurement precision can be improved, but device complexity and ease of operation worsen due to user-intensive calibration procedures
Solution Approach 1:
The patent implements a self-calibrating system where the calibration controller automatically performs the calibration process without user intervention. The system uses its own internal resources (power supply, signal processing circuits) to measure the current division ratio and adjust its output parameters autonomously, eliminating the need for external calibration equipment and user-intensive procedures.
Solution Approach 2:
The calibration controller continuously monitors the current division ratio and automatically adjusts the output signal parameters to maintain accuracy. This closed-loop feedback mechanism eliminates manual calibration steps and compensates for manufacturing tolerances in real-time, simplifying operation while maintaining high measurement precision.
3Measurement precision
If external calibration equipment and procedures are used, then measurement accuracy can be improved, but ease of manufacture and device complexity worsen
Solution Approach 1:
The patent integrates the calibration functionality within the current sensor itself, using the calibration controller to perform self-calibration during normal operation. This eliminates the need for external calibration equipment and complex assembly procedures, as the system calibrates itself using its own internal circuits and power supply, thereby improving ease of manufacture while maintaining accuracy.
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 self-calibration feature enhances current transient survival and over-current capability while simplifying the design and reducing costs by minimizing user input and complexity, providing accurate current measurements despite current divider configuration variability.
Implementation Method 1
The magnetic field transducer generates an output signal having a magnitude proportional to the magnetic field induced by a current that flows through the current conductor
Implementation Method 2
The controllable gain stage is configured to amplify the magnetic field signal with an adjustable gain to provide an amplified magnetic field signal
Data Source
AI summary
An integrated circuit (IC) current sensor that self-calibrates to adjust its signal gain when employed in a current divider configuration is presented. The current sensor includes an integrated current conductor, a magnetic field transducer, a controllable gain stage and a calibration controller. The integrated current conductor is adapted to receive a portion of a calibration current. The calibration current corresponds to a full scale current. The magnetic field transducer, responsive to the calibration current portion, provides a magnetic field signal having a magnitude proportional to a magnetic field generated by the calibration current portion. The controllable gain stage is configured to amplify the magnetic field signal with an adjustable gain to provide an amplified magnetic field signal. The calibration controller is responsive to a calibration command signal to adjust the adjustable gain of the controllable gain stage to a calibrated gain in order to provide the amplified magnetic field signal at a predetermined voltage level that corresponds to a desired current sensor output signal voltage level if the full scale current were received by the integrated current conductor.