Semiconductor Assembly With Integrated Sensing Coil for Current Detection
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Solution Overview
Problem
Conventional methods for sensing load or phase current in power converters, such as Hall-effect-sensors and on-chip current mirrors, are costly, space-consuming, and introduce ohmic losses or reduce active area, making them inefficient for closed-loop control in power conversion applications.
Innovation Solution
A semiconductor assembly with a sensing coil integrated in a chip-scale package that detects magnetic flux associated with the current path, allowing for efficient and cost-effective load current sensing without external circuitry, while minimizing capacitive coupling and common-mode distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall-effect-sensors are used for current sensing, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The sensing coil is integrated directly into the semiconductor assembly body, merging the current sensing function with the semiconductor package structure. This eliminates the need for separate Hall-effect-sensors and their associated mounting requirements, reducing assembly complexity while maintaining sensing capability
Solution Approach 2:
A sensing coil is introduced as an intermediary element that detects the magnetic flux generated by the current path. This coil provides a simplified interface between the current flow and the control circuitry, enabling accurate current sensing without complex sensor assemblies
2Device complexity
If on-chip current mirror is integrated, then device complexity is reduced, but active area is reduced and on-state resistance increases
Solution Approach 1:
The sensing function is moved from the chip plane to the vertical dimension by positioning the sensing coil within the body structure surrounding the current path. This three-dimensional integration allows current sensing without consuming valuable planar active area on the chip surface
Solution Approach 2:
The electrical current mirror approach is replaced with a magnetic field-based sensing mechanism. The sensing coil detects the magnetic flux generated by the current, substituting the need for parallel current mirror circuits and eliminating the associated active area consumption and on-resistance increase
3Measurement precision
If shunt resistors are used, then measurement precision is improved, but energy loss increases
Solution Approach 1:
The resistive shunt method is replaced with inductive sensing using a coil that detects magnetic flux. This substitution eliminates the need for low-value resistors that cause ohmic losses, achieving accurate current sensing through magnetic field detection instead of voltage drop measurement
4Device complexity
If sensing coil is integrated in body, then device complexity is reduced and space consumption is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The sensing coil is constructed from multiple discrete windings that can be individually positioned and connected. This segmentation allows for modular integration into the body structure, reducing the overall manufacturing precision requirements compared to a single complex coil structure
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
Enables simple, efficient, and cost-effective closed-loop control of power conversion with reduced space consumption and minimal distortion, suitable for fast-switching devices, by directly integrating a sensing coil within the semiconductor assembly to generate a sensor output in the Volt range for further signal processing.
Implementation Method 1
a magnetic flux associated with an electric current propagating along a current path in a vertical direction causes a detectable voltage in the sensing coil
Implementation Method 2
a magnetic flux associated with an electric current propagating along a current path in a vertical direction causes a detectable voltage in the sensing coil
Data Source
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AI summary
A semiconductor assembly and a corresponding electric device with improved current sensing capabilities are provided. The semiconductor assembly comprises a body with a bottom side and a top side and a vertical extension from the bottom side and the top side. Further the semiconductor assembly comprises a semiconductor element arranged in the body and a sensing coil arranged in the body. The sensing coil has at least one winding. The sensing coil is provided and adapted such that a magnetic flux associated with an electric current propagating along a current path in a vertical direction causes a detectable voltage in the sensing coil.