Integrated Current Sensor Package Inductive Coupling
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Solution Overview
Problem
Existing current sensors in power electronic circuits face challenges such as high loss, high cost, and accuracy issues, particularly in detecting currents in both DC and AC systems, with current transformer solutions being large and having medium loss, while hall effect devices and magneto resistive sensors suffer from noise and cost concerns.
Innovation Solution
An integrated current sensor package is developed, featuring a coil in a metal layer of an integrated circuit inductively coupled with a nearby wire, allowing for low-loss, low-cost, and high-accuracy current sensing with minimal signal distortion, suitable for both DC and AC applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a resistor is used to sense current, then the circuit can detect current in DC applications, but the loss is high and the signal detected is reduced when resistor value is lowered
Solution Approach 1:
The patent replaces the traditional resistive sensing mechanism with an inductive sensing mechanism using a coil. Instead of measuring voltage drop across a resistor, the system detects current through magnetic coupling between a current-carrying wire and a sensing coil, eliminating the direct electrical connection and associated losses while maintaining measurement capability.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the current-carrying wire and the sensing coil. The wire generates a magnetic field that couples inductively to the coil, allowing current detection without direct electrical contact. This intermediary enables energy-efficient sensing while preserving signal integrity.
2Loss of energy
If a hall effect device is used, then the circuit has low loss, but the cost is higher and accuracy and noise issues are greater
Solution Approach 1:
The patent employs a simple coil structure that can be manufactured using standard integrated circuit metal layers, replacing expensive hall effect devices. The coil is created through conventional photolithography and metal deposition processes, making it a cost-effective solution that achieves comparable or superior performance without specialized components.
Solution Approach 2:
The patent merges the sensing coil directly into the integrated circuit's metal layers, combining the sensing function with the existing IC structure. This integration eliminates the need for separate hall effect device packages and reduces overall system cost while improving accuracy through precise geometric control of the coil structure.
3Loss of energy
If a magneto resistive sensor is used, then current can be sensed with very low loss, but the cost is raised due to special technology and accuracy issues arise
Solution Approach 1:
The patent replaces complex magneto resistive sensor technology with a simple inductive coil structure. Instead of relying on specialized magneto resistive materials and processes, the system uses fundamental electromagnetic induction with a coil that can be fabricated using standard IC metal layers, dramatically simplifying manufacturing while maintaining low loss performance.
Solution Approach 2:
The patent changes the sensing mechanism from resistive measurement (magneto resistive) to inductive measurement (coil coupling). This parameter change in the detection method allows the use of conventional IC fabrication processes rather than specialized magneto resistive technology, reducing manufacturing cost and complexity while preserving low loss characteristics.
4Measurement precision
If a current transformer is used, then current can be detected in AC circuits, but the device is large and has medium loss level
Solution Approach 1:
The patent nests the sensing coil within the integrated circuit structure itself, placing it in the metal layers of the IC. This nested approach eliminates the need for external current transformer components, reducing size dramatically while minimizing loss through direct integration and optimized magnetic coupling geometry.
Solution Approach 2:
The patent transitions from a three-dimensional external transformer structure to a planar two-dimensional coil pattern within the IC metal layers. This dimensional change allows the sensing function to be integrated directly into the chip footprint, reducing size while maintaining detection capability and lowering loss through close proximity coupling.
5Device complexity
If a Rogowski coil is used, then the structure is simple and has wide bandwidth, but the voltage induced is very small and easily disturbed for currents less than 100 Amps
Solution Approach 1:
The patent combines the Rogowski coil sensing approach with integrated circuit implementation by creating the coil within IC metal layers and integrating the signal conditioning circuitry on the same chip. This merging amplifies the weak induced voltage through on-chip operational amplifiers and filtering, maintaining the simplicity of the sensing structure while dramatically improving signal strength and noise immunity for low current measurements.
Solution Approach 2:
The patent introduces on-chip operational amplifiers and signal conditioning circuits as intermediaries between the Rogowski coil and the output. These intermediary circuits amplify the small induced voltage and filter noise, enabling accurate measurement of currents below 100 Amps while preserving the structural simplicity and wide bandwidth characteristics of the Rogowski coil approach.
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 integrated current sensor package achieves low-loss, low-cost, and high-accuracy current sensing, effectively addressing the shortcomings of prior art methods by utilizing inductive coupling between the coil and wire, enabling precise current detection with reduced noise and cost, and supporting currents up to 10 amps.
Implementation Method 1
A coil in a metal layer of the integrated circuit is inductively coupled with a nearby wire
Data Source
AI summary
An integrated current sensor package includes an integrated circuit having a coil in a metal layer of the circuit. A wire is placed close enough to the coil such that the coil and the wire are inductively coupled with each other.