Current Sensor with Nested Magnetic Sensors for Noise Cancellation
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Solution Overview
Problem
Conventional current sensors face challenges in achieving high sensitivity and accuracy due to external noise interference, particularly in detecting small currents, and often require complex configurations to minimize noise effects.
Innovation Solution
The current sensor design incorporates two conductors with bent portions and magnetic sensors arranged within a sealing portion, where the magnetic fields applied to the sensors are opposite in direction, allowing for the calculation of the difference between their outputs to enhance sensitivity and reduce noise interference, while also utilizing a signal processing circuit to process these signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current sensors use magnetic sensors such as Hall elements and magnetic resistance elements, then the sensor can detect current, but the sensitivity is insufficient and external noise interference affects measurement accuracy
Solution Approach 1:
The patent divides the current detection function into two separate conductors with magnetic sensors, allowing independent optimization of each sensor's position and configuration while maintaining overall system functionality. This segmentation enables better noise isolation and sensitivity optimization for each measurement channel.
Solution Approach 2:
The patent utilizes the harmful external noise field by having it affect both magnetic sensors in the same way, then uses the difference amplifier to convert this common-mode noise into a rejectable signal. The noise that would normally degrade measurement accuracy is transformed into a cancelable common-mode component, allowing the differential measurement to extract the true current signal.
2Measurement precision
If the current sensor uses a differential configuration with two conductors and magnetic sensors, then noise cancellation is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the two conductor-magnetic sensor assemblies into a single integrated current sensor device with a unified housing and common signal processing circuitry. This combining approach reduces the overall complexity compared to using two separate sensors while maintaining the differential measurement capability for noise cancellation.
Solution Approach 2:
The signal processing circuit is designed to handle multiple functions: amplifying the differential signal from the two magnetic sensors, rejecting common-mode noise, and providing output signaling. This multi-functional design reduces the need for separate dedicated circuits for each function, thereby reducing overall device complexity.
3Measurement precision
If the magnetic sensors are positioned inside the conductors in the planar view, then the magnetic field detection is optimized, but the sealing portion design becomes more complex
Solution Approach 1:
The patent places the magnetic sensors inside the conductors in the planar view, creating a nested configuration where the sensor is positioned within the conductor's boundary. This nesting optimizes the magnetic field detection by placing the sensor in the region of strongest magnetic field while maintaining a compact overall structure that simplifies the sealing design.
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
This configuration significantly improves the sensitivity and accuracy of current detection by canceling out external noise and allowing for precise measurement of currents, even at small magnitudes, while maintaining a compact and efficient design.
Implementation Method 1
a magnetic field applied to a position of the first magnetic sensor due to the current under measurement flowing through the first conductor
Implementation Method 2
uses magnetic sensors such as Hall elements and magnetic resistance elements
Data Source
AI summary
To provide a current sensor with high sensitivity, provided is a current sensor including a sealing portion; a first conductor that includes a bent portion bent in a planar view within the sealing portion and two end portions that are exposed from the sealing portion; a second conductor that includes a bent portion bent in the planar view within the sealing portion and two end portions that are exposed from the sealing portion; a first magnetic sensor that is provided within the sealing portion and arranged inside the first conductor in the planar view; and a second magnetic sensor that is provided within the sealing portion and arranged inside the second conductor in the planar view, wherein one end portion of the first conductor and one end portion of the second conductor are electrically connected.