Wheatstone Bridge Sensor Circuit for Simultaneous Disturbance and Offset Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sensor technologies face challenges in simultaneously removing disturbances and offsets, leading to increased complexity, volume, and correction time, as existing methods typically address only one factor at a time.
Innovation Solution
A method and apparatus utilizing a differential structure of Wheatstone bridge type sensors, where a bias current is applied in both directions to measure voltages, allowing for the calculation of a final measurement value that accounts for and corrects both disturbances and offsets using the formula (V1−V2−V3+V4)/4, thereby simplifying the correction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic field shielding film is installed to prevent disturbance, then measurement precision is improved, but device complexity and volume increase
Solution Approach 1:
The patent extracts the disturbance correction function from physical shielding and implements it through a differential measurement circuit that mathematically eliminates disturbance effects. By using two sensors and differential amplification, the disturbance component is extracted and cancelled out in the calculation, removing the need for physical shielding films.
Solution Approach 2:
The patent replaces the mechanical/physical shielding film with an electronic/software-based correction system. Instead of using a magnetic shielding film to physically block disturbances, the system uses differential measurement and calculation to electronically eliminate disturbance effects, substituting physical protection with intelligent signal processing.
2Measurement precision
If separate correction circuits for disturbance and offset are used, then measurement precision is improved, but device complexity and volume increase
Solution Approach 1:
The patent merges the disturbance correction and offset correction functions into a single integrated correction process. By using a differential measurement system with two sensors and combining multiple measurement steps into one unified approach, the system simultaneously corrects for both disturbance and offset without requiring separate correction circuits, thereby reducing overall device complexity.
Solution Approach 2:
The differential measurement circuit serves multiple functions simultaneously: it measures the target signal, corrects for disturbance, corrects for offset, and produces the final corrected output. This multi-functional approach eliminates the need for separate dedicated correction circuits, reducing device complexity while maintaining measurement precision.
3Measurement precision
If two types of correction circuits are required for disturbance and offset, then measurement precision is improved, but productivity decreases due to increased correction time
Solution Approach 1:
The patent performs preliminary measurements to characterize the sensor's disturbance and offset characteristics before final measurement. By conducting calibration measurements in advance and storing the characteristics, the system can quickly apply corrections during actual measurement without requiring complex real-time correction processing, thereby improving productivity while maintaining precision.
Solution Approach 2:
The differential measurement system continuously corrects for disturbance and offset throughout the measurement process rather than requiring separate correction steps. The correction is applied continuously and simultaneously with the measurement, eliminating idle correction time and improving overall measurement productivity while maintaining high precision.
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 approach enables simultaneous removal of disturbances and offsets in a single circuit, reducing complexity, volume, and correction time, while providing accurate measurements of current and magnetic field sizes.
Implementation Method 1
a magnetic field generated by a current to be measured
Implementation Method 2
A current sensor using the indirect measurement method may use a magneto resistance (MR) effect that a resistance value is changed according to a size of a magnetic field
Data Source
AI summary
A measurement method and apparatus for correcting a disturbance and an offset of a sensor simultaneously are described. The method includes applying a bias current to first and second sensors of a Wheatstone bridge type connected with each other as a differential structure, and measuring a voltage of the first sensor and a voltage of the second sensor. The method also includes applying a bias current to the first and second sensors in a direction opposite to the direction in the first applying, and measuring a voltage of the first sensor and a voltage of the second sensor. The method further includes calculating a final measurement value based on the measured voltages. Accordingly, the offset and the influence of the disturbance of the sensor can be simultaneously removed through one circuit, such that advantageous effects such as reduced complexity, reduced area/volume, and shortened correction time can be achieved.