Magnetoresistive Current Sensor With EMI Protection Circuitry
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Solution Overview
Problem
Current sensors in electric vehicles face challenges of precision, speed, size, energy consumption, stability, electromagnetic interference, and manufacturing cost, particularly in high-noise environments with continuous high-power electrical switching and metallic elements.
Innovation Solution
An electrical current sensor using magnetoresistive integrated circuits (TMR, GMR, or AMR) with additional circuitry for noise protection, mounted on a PCB in a plastic casing, enabling contact-free measurement and electromagnetic immunity, with optional wireless communication and temperature sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current sensing technologies are used, then the sensor can measure current, but the sensor size, weight, and energy consumption increase
Solution Approach 1:
The patent replaces conventional mechanical/electromagnetic current sensing mechanisms with a magnetoresistive integrated circuit that detects magnetic field changes caused by current flow. This substitution of the sensing mechanism enables precise current measurement while significantly reducing sensor weight and size, as the magnetoresistive IC is much lighter than traditional current transformer cores or Hall effect sensors.
Solution Approach 2:
The patent utilizes changes in electrical resistance of the magnetoresistive material in response to magnetic field variations. By measuring the resistance change parameter of the magnetoresistive element, the system achieves precise current measurement with minimal sensor mass, resolving the contradiction between measurement precision and sensor weight.
2Measurement precision
If conventional current sensing technologies are used, then the sensor can measure current, but the response speed decreases and energy consumption increases
Solution Approach 1:
The replacement of conventional current sensing with a magnetoresistive integrated circuit provides faster response speed because magnetoresistive materials respond instantaneously to magnetic field changes without the mechanical inertia or bandwidth limitations of traditional sensors. This enables real-time current measurement while maintaining high precision.
3Reliability
If additional protection circuitry is added to the sensor, then electromagnetic immunity improves, but device complexity increases
Solution Approach 1:
The patent integrates the magnetoresistive sensing element, signal conditioning circuitry, and protection features into a single integrated circuit device. This merging of multiple functions into one compact IC achieves high electromagnetic immunity through built-in protection while avoiding the complexity increase that would result from assembling separate protective components.
Solution Approach 2:
The magnetoresistive integrated circuit acts as an intermediary between the harsh electromagnetic environment and the measurement system. It provides inherent immunity to electromagnetic interference and includes protection circuitry that mediates against voltage spikes and noise, achieving reliable operation without adding external complexity.
4Measurement precision
If the sensor is designed for high precision measurement, then measurement accuracy improves, but manufacturing cost increases
Solution Approach 1:
The use of a magnetoresistive integrated circuit replaces complex mechanical adjustment and calibration mechanisms required for high-precision current sensing. The IC provides precise measurement through its inherent magnetic field sensitivity, eliminating the need for expensive mechanical assemblies, alignment procedures, and manual calibration, thereby reducing manufacturing costs while maintaining high accuracy.
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 sensor achieves improved precision, faster response, reduced size and weight, lower energy consumption, and lower manufacturing costs while maintaining high electromagnetic immunity and stability.
Implementation Method 1
The sensor can be comprised of a magnetoresistive type integrated circuit such as TMR, GMR or AMR
Implementation Method 2
The sensor can be comprised of a magnetoresistive type integrated circuit such as TMR, GMR or AMR, or a Hall effect type magnetic integrated circuit
Implementation Method 3
additional circuitry to protect the sensor from possible surges, and electrical and electromagnetic noise, thus providing electromagnetic immunity
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a current sensor formed by an integrated circuit (6), preferably of the TMR magnetic type, mounted on a PCB (5) and also comprising additional circuitry to protect the sensor from possible surges and electrical and electromagnetic noise, thus providing electromagnetic immunity. All these components are mounted in a casing (1) typically made of plastic, preferably with an opening for connecting the system. An electrically conductive bar or busbar (4) may be inserted through the casing to allow the circulation of the electrical current to be measured. The sensor provides an analogue output proportional to the current of an electrical conductor inserted through the casing.