Cascade Magnetic Sensor Circuit for Linear Field Sensing
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Solution Overview
Problem
Existing magnetic sensors face challenges in achieving high linearity without compromising sensitivity, and existing solutions for correcting non-linearities often require complex integrated circuits, high power consumption, and large die areas.
Innovation Solution
A cascade magnetic sensor circuit comprising multiple magnetic sensors connected in series, where each sensor's output voltage is used as the input bias voltage for the next, generating a corrected output voltage through a cascade configuration that compensates for high-order components, thereby improving linearity without relying on CMOS processing or analog IC development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the magnetoresistive element is improved to ensure linear Vout response and larger working magnetic field ranges, then linearity is improved, but sensor sensitivity and magnetic field resolution are reduced
Solution Approach 1:
The patent divides the correction function into separate stages by using multiple magnetic sensors in cascade. Each sensor handles a portion of the correction task, with the output of one sensor serving as the input bias for the next. This segmentation allows each sensor to operate optimally for its specific function while collectively achieving both linearity and sensitivity.
Solution Approach 2:
The patent changes the operating parameters of the magnetic sensors dynamically through cascade connection. The output voltage of each sensor becomes the input bias voltage for the next sensor, creating a dynamic parameter adjustment mechanism that adapts to different magnetic field conditions while maintaining both linearity and sensitivity.
2Manufacturing precision
If an integrated circuit is implemented to correct non-linearities and obtain high linear corrected output voltage, then linearity is improved, but the device becomes more limited to work at high frequencies
Solution Approach 1:
The patent replaces complex analog IC correction circuits with a simpler cascade of magnetic sensors. This substitution eliminates the need for sophisticated IC-based non-linearity correction while maintaining linearity improvement, thereby preserving high-frequency operation capability.
Solution Approach 2:
The patent uses multiple identical or similar magnetic sensor units in cascade, replacing expensive and complex IC correction circuits. This approach achieves linearity correction through the collective action of simple sensor units rather than through complex integrated circuitry that would limit high-frequency performance.
3Manufacturing precision
If lookup table or correction polynomial is used to correct non-linearities, then linearity is improved, but power consumption increases and die area enlarges
Solution Approach 1:
The patent replaces digital correction methods (lookup tables, correction polynomials requiring ADCs, DACs, memory, and microcontrollers) with an analog cascade of magnetic sensors. This substitution eliminates the need for high-power digital processing while achieving linearity correction through analog signal processing.
Solution Approach 2:
The patent uses simple magnetic sensor units in cascade rather than complex digital correction systems. This approach achieves linearity correction through the physical cascade connection of sensors, eliminating the need for power-intensive digital processing components and large die areas.
4Manufacturing precision
If complex IC is used to correct non-linearities, then linearity is improved, but device complexity increases
Solution Approach 1:
The patent segments the correction function across multiple simple magnetic sensor units rather than implementing it through a single complex IC. Each sensor unit is identical or similar, and they work together in cascade to achieve the correction, simplifying the overall device architecture.
Solution Approach 2:
The patent makes the magnetic sensor units universal and multi-functional. Each sensor serves both as a sensing element and as a bias generator for the next sensor in the cascade. This universality reduces device complexity by eliminating the need for separate correction circuitry.
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 cascade configuration achieves improved linearity and sensitivity across varying magnetic field amplitudes and orientations, with reduced temperature dependence, enabling broader operational ranges and efficient bandwidth operation.
Implementation Method 1
Sensor technologies using Magnetic Tunnel Junctions (MTJs) based on Tunnel Magneto-Resistance (TMR) effect excel among rival technologies
Implementation Method 2
each magnetic sensor outputs an output voltage Voutn, the magnetic sensors being electrically connected in cascade with each other, wherein the output voltage Voutn of the nth magnetic sensor of the cascade magnetic sensor circuit supplies the input bias voltage Vdd_n+1 of the next magnetic sensor (n+1)th
Data Source
AI summary
The present disclosure concerns magnetic sensor device (10) for sensing an external magnetic filed vector (H) comprising a cascade magnetic sensor circuit (100) comprises N magnetic sensors (2n), wherein N equal to or greater than 2, wherein said N magnetic sensors (2n) comprises a first magnetic sensor (21) and at least another magnetic sensor (2n) electrically connected in cascade with each other. The first magnetic sensor (21) is configured to generate a first output voltage (Vout1) dependent on an external magnetic field vector (H) when inputted with an input bias voltage (Vdd). The output voltage of the nth magnetic sensor is used as input bias voltage of the next (n+1) magnetic sensor. The magnetic sensor device (10) further comprises at least one reference magnetic field sensor (2Ref). The corrected output voltage has improved linearity compared to the reference output voltage.