Current Sensor Package With Wing Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Accurately measuring current through a conductor is challenging in systems susceptible to stray magnetic fields, and placement tolerances can lead to sensing errors, increasing manufacturing time and cost.
Innovation Solution
The implementation of differential current sensing in a current sensor integrated circuit (IC) package with a single in line package configuration and a wing structure, which improves mechanical mounting tolerances and reduces the adverse effects of stray magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current sensing methods are used in systems susceptible to stray magnetic fields, then current measurement can be performed, but measurement precision deteriorates due to sensing errors from stray fields and placement tolerances
Solution Approach 1:
The patent employs differential current sensing that intentionally exploits the presence of stray magnetic fields by using two sensing elements positioned to experience opposite polarities of the same field. The harmful stray fields that would normally cause measurement errors are converted into a useful differential signal configuration where they affect both sensing elements equally but in opposite directions, allowing them to be rejected through differential processing.
Solution Approach 2:
The patent positions two magnetic field sensing elements at different locations relative to the current-carrying conductor, specifically on opposite sides or at different heights, so that they experience different local magnetic field conditions. This local differentiation allows one element to sense the current-generated field with positive polarity while the other senses it with negative polarity, enabling spatial discrimination of the magnetic field signal.
2Measurement precision
If calibration procedures are performed to compensate for placement tolerances, then measurement precision improves, but manufacturing time and cost increase
Solution Approach 1:
The patent performs offset calibration during the manufacturing process rather than requiring end-of-line calibration in the application setting. By completing the calibration action preliminarily during manufacturing, the system eliminates the need for time-consuming calibration procedures at the customer site, reducing both manufacturing time and overall system deployment time while maintaining measurement precision.
Solution Approach 2:
The differential sensing configuration inherently compensates for placement tolerances through its symmetric geometry. The system self-corrects for variations in positioning because any stray magnetic field or placement error affects both sensing elements equally, and the differential processing automatically rejects these common-mode errors without requiring external calibration intervention.
3Measurement precision
If a ferrite core is used to concentrate the magnetic field, then measurement precision improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the ferrite core component from the current sensor design, creating a coreless current sensor. By removing this complex magnetic concentrating element, the patent simplifies the device structure, reduces manufacturing steps, and lowers costs while maintaining measurement capability through direct sensing of the magnetic field generated by the current-carrying conductor.
Solution Approach 2:
The patent replaces the expensive, complex ferrite core with a simpler, more cost-effective sensing arrangement using two magnetic field sensing elements positioned near the conductor. This substitution uses cheaper components that are easier to manufacture and assemble, reducing overall device cost and complexity while achieving the same functional goal of current measurement.
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 achieves highly repeatable, tightly controlled, and accurate current sensor performance, reducing the need for end-of-line calibration and minimizing manufacturing costs.
Implementation Method 1
magnetic field sensing elements configured to sense a magnetic field generated by the current through the bus bar
Implementation Method 2
circuit responsive to the magnetic field signals from the at least two magnetic field sensing elements and configured to generate a current sensor output signal based on a difference between the magnetic field signals
Data Source
AI summary
A current sensor IC includes a lead frame having a die attach pad and elongated leads extending in a single direction with respect to the die attach pad, a semiconductor die having a first surface attached to the die attach pad and a second, opposing surface supporting magnetic field sensing elements, and a non-conductive mold material. A first portion of the mold material encloses the semiconductor die and the die attach pad, a second portion of the mold material encloses a portion of the elongated leads, and the mold material further includes a wing structure between the first portion and the second portion. In assembly, the first portion of the mold material extends into a cutout through a current conductor and the wing structure abuts a surface of the conductor. The current sensor can implement differential sensing based on signals from at least two magnetic field sensing elements.