AMR Magnetic Field Sensor with Overcurrent Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Anisotropic-magnetoresistive (AMR) magnetic field sensors face limitations in accurately measuring magnetic fields beyond a certain threshold, leading to undetected overcurrent issues, particularly in high-field applications like motor commutation, where current increases can exceed sensor capabilities within a short time frame, resulting in potential overheating and damage.
Innovation Solution
Incorporating an additional AMR-based overcurrent detection sensor in conjunction with the existing AMR field sensor, utilizing a half bridge configuration with field-insensitive components, such as barber pole resistors or multiple AMR sensing elements, to detect high magnetic fields indicative of excess current, thereby extending the measurement range and preventing overcurrent conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an AMR magnetic field sensor is used to measure external magnetic fields, then measurement precision is improved within a certain range, but measurement capability deteriorates beyond a threshold magnetic field strength
Solution Approach 1:
The patent divides the magnetic field sensing function into two separate sensors: an AMR sensor for precise measurement within the normal range, and an overcurrent detection sensor (using Hall effect or other mechanisms) for detecting fields beyond the threshold. This segmentation allows each sensor to operate in its optimal range, resolving the contradiction between precision and measurement range.
Solution Approach 2:
The patent creates a dual-sensor system where the AMR sensor handles precise measurements in normal operating conditions, while the overcurrent detection sensor handles extreme conditions. Together, they provide universal coverage across the entire magnetic field range, from low-field precise measurement to high-field overcurrent detection.
2Productivity
If the AMR sensor operates in high magnetic fields beyond its threshold, then the system can handle high current conditions, but detection accuracy deteriorates and overcurrent goes undetected
Solution Approach 1:
The patent introduces an intermediary overcurrent detection sensor that specifically monitors magnetic fields beyond the AMR sensor's threshold. This intermediary sensor takes over the detection function in high-field conditions, ensuring accurate overcurrent detection without compromising the AMR sensor's precision in its optimal range.
Solution Approach 2:
The patent implements a feedback mechanism where the outputs of both the AMR sensor and the overcurrent detection sensor are monitored. When the magnetic field exceeds the AMR sensor's threshold, the system receives feedback from the overcurrent detection sensor, enabling accurate detection and appropriate system response to overcurrent conditions.
3Device complexity
If the system relies solely on the AMR sensor for magnetic field detection, then device complexity is reduced, but reliability deteriorates in high-field applications
Solution Approach 1:
The patent applies beforehand cushioning by pre-configuring the overcurrent detection sensor to activate when the AMR sensor reaches its threshold. This preparatory arrangement ensures that protection is already in place before overcurrent damage occurs, maintaining reliability without requiring complex real-time switching or additional control logic.
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 effectively detects high electrical currents and magnetic fields beyond the threshold of the AMR field sensor, preventing overcurrent and overheating by providing an additional output signal for magnetic field strength above the threshold, thus enhancing the system's operational safety and accuracy.
Implementation Method 1
Anisotropic-magnetoresistive (AMR) sensors are used to sense external magnetic fields by detecting a change in resistance of the sensor as a result of the external magnetic field
Data Source
AI summary
The present disclosure provides a magnetic field sensor system, comprising an AMR magnetic field sensor and an overcurrent detection sensor. The overcurrent detection sensor comprises an AMR sensing element connected in a half bride arrangement with a field insensitive component. The output of the overcurrent detection sensor is able to monitor the strength of the magnetic field experiences by the sensor system, and detect if the magnet field goes beyond a sensing threshold of the AMR magnetic field sensor. Outside of this threshold, the AMR magnet field sensor is unable to provide a measurement of the magnetic field strength. The overcurrent detection sensor can therefore detect that the system is operating in very high magnetic fields, which in turn can indicate that there is overcurrent in the system.