MTJ Signal Isolator Shielding Against Coil Electric Field Damage
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Solution Overview
Problem
Existing magnetic tunnel junction signal isolators are vulnerable to destruction by electric fields generated due to potential differences between the coil and magnetic sensor reference grounds, which can break down the magnetic tunnel junctions.
Innovation Solution
Incorporating an electric shielding layer between the coil and the magnetoresistive sensor, along with a magnetic shielding layer, to neutralize the electric field interference and protect the magnetic tunnel junctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only magnetic shielding layer and insulating layer are used, then magnetic field isolation is achieved, but electric field interference destroys the magnetic tunnel junction
Solution Approach 1:
An electric shielding layer made of conductive material is introduced as an intermediary between the coil and the magnetoresistive sensor. This intermediate layer redirects the electric field lines around the magnetic tunnel junction, preventing direct electric field damage while maintaining the magnetic field coupling necessary for signal transmission.
Solution Approach 2:
The shielding structure uses composite material configuration by combining magnetic shielding material (for magnetic field isolation) with electric shielding material (for electric field protection). This composite approach addresses both magnetic and electric field interference simultaneously, protecting the magnetic tunnel junction from both types of harmful effects.
2Reliability
If electric shielding layer is added between coil and magnetoresistive sensor, then electric field protection is achieved, but device structure becomes more complex
Solution Approach 1:
The electric shielding layer is designed to serve multiple functions: it provides electric field shielding, acts as an electrical connection reference, and can be integrated with existing PCB ground planes. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The electric shielding layer is electrically connected to the reference ground of the magnetoresistive sensor, merging the shielding function with the existing ground reference structure. This integration approach combines multiple functions into a single structural element, reducing overall device complexity.
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 electric shielding layer effectively shields the magnetoresistive sensor from electric field damage, preventing breakdowns and maintaining the integrity of the magnetic tunnel junctions.
Implementation Method 1
an electric shielding layer, located between the coil and the magnetoresistive sensor
Implementation Method 2
a magnetic shielding layer is also arranged above or below the coil and the magnetic sensor. In order to prevent interference from an external magnetic field
Implementation Method 3
The magnetoresistive sensor is composed of a plurality of magnetic tunnel junctions
Data Source
AI summary
Disclosed in the embodiments of the present invention is a magnetic tunnel junction signal isolator with electric shielding layer. In the isolator, a coil is located between a magnetic shielding layer and an electric shielding layer; the electric shielding layer is located between the coil and a magnetoresistive sensor, the magnetoresistive sensor is composed of a plurality of magnetic tunnel junctions that are connected in a series-parallel way. The two ends of the coil are electrically connected to a circuit having a first reference ground used to send a signal; a signal is sent from the magnetoresistive sensor to a receiving circuit connected to a second reference ground. The magnetic shielding layer is electrically connected to the first reference ground in a single-point or multi-point mode, or it is completely electrically isolated from the first reference ground. The electric shielding layer may instead be electrically connected to the second reference ground in a single-point or multi-point mode, or it may be completely electrically isolated from the second reference ground. Or, the electric shielding layer and magnetic shielding layer are respectively electrically connected to any potential or potentials between the first reference ground and the second reference ground in a single-point or multi-point mode. The embodiments of the present invention, prevent the electric field from corrupting the magnetoresistive sensor signal, as such solving the problem of interference and damage caused to a magnetic tunnel junction in the magnetoresistive sensor by the coil.