Magnetoresistive Current Sensor with Isolation Unit
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Solution Overview
Problem
Current sensors face issues with low safety performance due to lack of electrical isolation and low sensitivity, particularly in traditional Ohm's law-based shunt resistors and Hall effect-based sensors.
Innovation Solution
An integrated current sensor with a magnetoresistive sensing and signal processing unit, an isolation unit, and a U-shaped conductor configuration that provides high sensitivity and electrical isolation between the current and signal sides, utilizing a Wheatstone bridge circuit and sintered samarium cobalt magnets for accurate signal output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a traditional Ohm's law-based shunt resistor is used, then the structure is simple, but electrical isolation between current side and signal side is lost and safety performance deteriorates
Solution Approach 1:
The current sensor is divided into distinct functional modules: a conductor for current flow, an isolation unit for electrical separation, and a magnetoresistive sensing unit for signal detection. This segmentation allows each component to perform its specific function while maintaining overall system reliability and safety through proper isolation.
2Reliability
If a Hall effect-based current sensor is used, then electrical isolation is achieved, but sensitivity decreases and noise increases
Solution Approach 1:
The patent replaces the Hall effect-based sensing mechanism with a magnetoresistive sensing mechanism. The magnetoresistive sensor detects changes in resistance based on magnetic field strength, providing higher sensitivity and lower noise while maintaining electrical isolation through the isolation unit. This substitution of the sensing principle resolves the contradiction between isolation and measurement precision.
3Measurement precision
If a magnetoresistive sensing unit is used, then sensitivity and integration degree improve, but electrical isolation between current side and signal side must be ensured
Solution Approach 1:
An isolation unit is introduced as an intermediary component between the conductor (current side) and the magnetoresistive sensing unit (signal side). This isolation unit maintains electrical isolation while allowing magnetic field coupling to pass through, enabling the magnetoresistive sensor to detect current-induced magnetic fields without direct electrical contact. The intermediary resolves the contradiction by providing both isolation and sensing capability.
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 solution achieves high sensitivity and integration with effective electrical isolation, enhancing safety performance and reducing noise, thereby addressing the limitations of existing current sensors.
Implementation Method 1
a magnetoresistive sensing and signal processing unit
Implementation Method 2
an isolation unit configured to be sandwiched between the magnetoresistive sensing and signal processing unit and the conductor
Implementation Method 3
utilizing a Wheatstone bridge circuit
Implementation Method 4
sintered samarium cobalt magnets for accurate signal output
Data Source
AI summary
An integrated current sensor is provided in the present invention. The integrated current sensor includes: a conductor comprising at least one current input pin, at least one current output pin, a first leg portion connected to the at least one current input pin, a second leg portion connected to the at least one current output pin, and a connection portion connected between the first leg portion and the second leg portion; a magnetoresistive sensing and signal processing unit; an isolation unit configured to be sandwiched between the magnetoresistive sensing and signal processing unit and the conductor; a plurality of signal pins configured for being coupled to the magnetoresistive sensing and signal processing unit via wires respectively; and a package body configured for wrapping part of the conductor, part of the signal pins, the isolation unit and the magnetoresistive sensing and signal processing unit. A direction of current on the first leg portion is opposite to a direction of current on the second leg portion. The signal pins, the at least one current input pin and the at least one current output pin are exposed from the package body. In this way, the integrated current sensor may realize good electrical isolation between a current side and a signal side. In addition, the integrated current sensor has high sensitivity and integration degree due to use of a magnetoresistive sensing way.