Wheatstone Bridge Sensor Offset Calculation via Node Resistance
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Solution Overview
Problem
Existing methods for calculating the offset of Wheatstone bridge type sensors are cumbersome and require individual measurement for each sensor, making them time-consuming and costly, especially since offset voltages vary with bias current.
Innovation Solution
A method and apparatus that calculate the offset of Wheatstone bridge type sensors using measured resistances between nodes, expressed as an equation independent of bias current, simplifying the calculation to (RA−RB+RC−RD)/2, where RA, RB, and RC are resistances between nodes, allowing for rapid and cost-effective offset determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual measurement is performed for each sensor to determine offset, then measurement precision is improved, but productivity deteriorates due to time-consuming processes
Solution Approach 1:
The invention changes the measurement parameter from offset voltage (which varies with bias current) to inter-node resistance values. By measuring resistances RA, RB, RC, and RD between nodes and using the formula (RA−RB+RC−RD)/2, the offset can be calculated independently of bias current, enabling rapid calculation without individual voltage measurements for each sensor.
2Measurement precision
If complex measurement and calculation procedures are used to determine offset, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The invention extracts the essential information needed for offset calculation by measuring only the four inter-node resistance values (RA, RB, RC, RD). This extraction approach eliminates the need for complex voltage measurements under different bias currents and amplifier connections, simplifying the measurement instrumentation while maintaining calculation accuracy through the resistance-based formula.
3Manufacturing precision
If individual offset measurement is performed for each sensor type and configuration, then manufacturing precision is improved, but loss of time increases due to repeated measurements
Solution Approach 1:
The invention creates a universal offset calculation method that works for all Wheatstone bridge type sensors regardless of their specific configuration or sensor type (magnetic sensors, current sensors, etc.). The resistance-based formula (RA−RB+RC−RD)/2 is universally applicable to any sensor with a Wheatstone bridge structure, eliminating the need for separate calibration procedures for different sensor types and configurations.
Data Source
AI summary
A method and an apparatus for calculating an offset of a Wheatstone bridge type sensor are described. The offset calculation method includes measuring resistances between nodes of a Wheatstone bridge type sensor, calculating an offset of the sensor using the measured resistances and providing information on the calculated offset. Accordingly, the offset of the Wheatstone bridge type sensor can be rapidly and easily calculated independently from the size of a bias current, and ultimately. Furthermore, time required to measure can be reduced and thus a sensor fabrication cost can be reduced, and also, mass production can be enhanced.