Characterization of Magnetoresistive Shunts and Its Sensitivity Temperature Compensation

Area of Science:

• Electrical Engineering
• Materials Science
• Sensor Technology

Background:

• Conventional shunt resistors for current sensing can lead to self-heating and lack galvanic isolation.
• Magnetoresistive (MR) elements are typically used in Wheatstone bridges for sensing applications.

Purpose of the Study:

• To demonstrate a single magnetoresistive (MR) element can function as a current sensor, termed a magnetoresistive shunt (MR-shunt).
• To develop electronic circuitry for utilizing integrated MR sensors as MR-shunts and for conditioning their signals.
• To analyze and compensate for thermal variations in MR-shunt sensitivity.

Main Methods:

• Proposed electronic circuitry to adapt MR sensors within a Wheatstone bridge as individual MR-shunts.
• Developed a conditioning circuit for both bridge-integrated and standalone MR elements to operate as current sensors.
• Investigated thermal sensitivity variations and implemented hardware-based compensation for thermal drift.

Main Results:

• Successfully demonstrated the MR-shunt concept for current sensing with galvanic isolation and reduced self-heating.
• Achieved significant reduction in temperature coefficients: from 0.348%/°C to -0.008%/°C for bridge elements and 0.474%/°C to -0.0007%/°C for single elements.
• Validated the effectiveness of the proposed electronic interface for thermal drift compensation.

Conclusions:

• The MR-shunt concept offers a novel, efficient, and isolated approach to current sensing using readily available MR elements.
• The developed electronic circuitry and compensation techniques enable robust MR-shunt current sensor applications across varying temperatures.
• This work paves the way for advanced, compact, and reliable current sensing solutions in various electronic systems.