Switchable Resistive Sensor Circuit for Low Residual Offset
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Solution Overview
Problem
Existing sensors, particularly those using electromagnetic flux sensing elements, face challenges in maintaining precise resistance balance and offset correction, which can affect their reliability and compliance with safety-critical applications.
Innovation Solution
A system comprising a sensing element with a switching matrix and a matrix controller that dynamically adjusts the total resistance by bringing resistive elements online or offline based on a counter signal, coupled with an autozero circuit to correct resistive imbalances and offset signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed resistance sensing element is used, then the circuit is simple, but the offset correction precision is insufficient
Solution Approach 1:
The sensing element is divided into multiple resistive elements (first, second, third, fourth resistive elements) that can be independently switched. This segmentation allows precise adjustment of total resistance to achieve better offset correction while maintaining a manageable structure through systematic switching control.
Solution Approach 2:
The sensing element transitions from a fixed resistance design to a dynamic resistance design where the total resistance can be changed by switching resistive elements online or offline. This dynamic adjustment capability enables precise offset correction while the system adapts to different operating conditions.
2Measurement precision
If resistive elements are switched dynamically, then offset correction is improved, but the control complexity increases
Solution Approach 1:
The system performs preliminary offset correction by switching resistive elements before normal measurement operations. The matrix controller pre-adjusts the resistance balance based on detected offset conditions, ensuring accurate measurements without requiring complex real-time adjustments during operation.
Solution Approach 2:
The matrix controller continuously monitors the offset signal and provides feedback control by switching resistive elements through the switching matrix. This closed-loop feedback mechanism automatically maintains resistance balance, reducing the need for manual intervention and simplifying overall system control.
3Reliability
If multiple resistive elements are used for precise resistance adjustment, then offset correction capability is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The system achieves precise resistance adjustment by changing the configuration parameters (which resistive elements are switched on/off) rather than requiring precise manufacturing of each individual resistor value. This allows standard manufacturing processes to be used while still achieving high reliability through programmable resistance adjustment.
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 system ensures precise resistance balance and offset correction, enhancing sensor reliability and compliance with safety-critical application standards by minimizing residual offsets and improving overall performance.
Implementation Method 1
Some sensors include one or more electromagnetic flux sensing elements, such as a Hall effect element
Implementation Method 2
Some sensors include one or more electromagnetic flux sensing elements, such as a Hall effect element, a magnetoresistive element
Data Source
AI summary
A system, comprising: a sensing element including a plurality of resistive elements; a switching matrix that is configured to change a total resistance of the sensing element by bringing online or offline one or more of the plurality of resistive elements, the total resistance of the sensing element, at any point in time, being based on respective resistances of only those of the plurality of resistive elements that are currently online; a matrix controller that is configured to detect when a value of a counter signal is updated and cause the switching matrix to change the total resistance of the sensing element by bringing offline or online one or more of the plurality of resistive elements based on the value of the counter signal; and a counter signal generator configured to detect whether an offset signal satisfies a predetermined condition and update the value of the counter signal.