Closed-Loop Current Sensor Sensitivity Adjustment via Secondary Conductor Selection
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Solution Overview
Problem
Closed-loop current sensors face challenges in adjusting sensitivity due to fixed coupling factors associated with primary and secondary conductors, making it difficult to compensate for fabrication and packaging variations without additional circuitry or external components.
Innovation Solution
The implementation of a closed-loop current sensor with a selection circuit that controls a plurality of secondary conductors, allowing for the adjustment of coupling factors to achieve desired sensitivity by selecting specific drive circuits and positioning of secondary conductors relative to the magnetic field sensing element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed coupling factors are used for primary and secondary conductors, then the closed-loop current sensor structure is simple, but sensitivity adjustment is difficult and requires additional external trim components
Solution Approach 1:
The patent applies the Dynamics principle by making the coupling factor adjustable rather than fixed. A selection circuit is provided that can selectively connect different secondary conductors to the magnetic field sensing element, allowing the coupling factor to be dynamically adjusted. This enables sensitivity trimming without requiring external components, as the adjustment is performed internally by selecting among multiple secondary conductor configurations.
Solution Approach 2:
The patent applies the Segmentation principle by dividing the secondary conductor system into multiple discrete secondary conductors (secondary conductor 1, secondary conductor 2, etc.), each with different coupling characteristics. The selection circuit can selectively activate different combinations of these segmented secondary conductors to achieve desired sensitivity levels, replacing the need for a single fixed secondary conductor configuration.
2Measurement precision
If sensitivity trimming is performed using external components, then sensitivity adjustment is possible, but the device requires additional external trim components and increased complexity
Solution Approach 1:
The patent applies the Self-service principle by implementing an internal selection circuit that performs sensitivity trimming autonomously without requiring external trim components. The selection circuit is integrated within the current sensor device and can selectively connect different secondary conductors to achieve the desired sensitivity, making the device self-sufficient for sensitivity adjustment.
Solution Approach 2:
The patent applies the Merging principle by combining the sensitivity adjustment functionality directly into the current sensor device through the integrated selection circuit. Instead of using separate external trim components, the patent merges the trimming function with the existing sensor structure by adding only the necessary switching elements within the device.
3Adaptability or versatility
If multiple secondary conductors are provided with different positions, then sensitivity adjustment range is increased, but the device structure becomes more complex
Solution Approach 1:
The patent applies the Dynamics principle by providing a selection circuit that can dynamically switch between different secondary conductor configurations. This allows the system to adapt its sensitivity characteristics by selecting appropriate secondary conductors based on the required measurement range, making the device versatile without permanently increasing the physical structure.
Solution Approach 2:
The patent applies the Universality principle by designing the secondary conductor system to serve multiple functions. The same set of secondary conductors can be selectively activated to provide different coupling factors, allowing a single device structure to handle multiple sensitivity requirements and application scenarios.
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 approach enables precise adjustment of sensitivity, reducing sensitivity drift and eliminating the need for external trim components, while maintaining stability and accuracy across temperature and packaging variations.
Implementation Method 1
a primary magnetic field generated by a sensed electrical current passing through a primary conductor is sensed with one or more magnetic field sensing elements
Implementation Method 2
a secondary magnetic field generated by another electrical current passing through a secondary conductor disposed in a feedback arrangement
Implementation Method 3
The closed loop current sensor uses negative feedback to generate the secondary current, which, in turn, generates the secondary magnetic field, which can be oriented to oppose, at the magnetic field sensing element, the primary magnetic field
Data Source
AI summary
A closed loop current sensor has a primary conductor and a plurality of secondary conductors. Selected ones of the plurality of secondary conductors are selected and driven in a feedback loop.