Multi-Contact Hall Sensor Offset Error Reduction
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Solution Overview
Problem
Multi-contact Hall sensors face significant challenges in reducing residual offset error, which remains high despite using spinning current-type modes, affecting their accuracy in sensing magnetic fields.
Innovation Solution
The implementation of sensor devices with three or more contacts that operate in multiple phases, where the supply and signal contacts are rearranged in each phase, allowing for the combination of output potentials or currents to cancel out offset errors, specifically through Iu-biasing and Ui-forcing modes that maintain constant current or voltage across phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a multi-contact Hall sensor is operated in a spinning current-type mode with multiple clock phases, then the supply or sense role of contacts is changed in multiple phases to reduce offset, but the residual offset error remains high (about 1 mT)
Solution Approach 1:
The sensor operation is divided into multiple discrete clock phases (first through fourth phases), where in each phase the supply and sense contacts are specifically assigned to different physical contacts. This segmentation allows systematic variation of the measurement configuration over time, enabling offset cancellation through combination of phased signals while maintaining high magnetic field detection capability.
Solution Approach 2:
The sensor employs periodic switching of contact roles across multiple clock phases. The supply contact and sense contact are periodically reassigned in each phase, creating a time-varying measurement system. This periodic action allows the output signals from different phases to be combined in a way that cancels residual offset errors while preserving the magnetic field signal.
2Measurement precision
If the supply and sense contacts are rearranged in multiple operating phases, then offset error cancellation is improved, but the device complexity increases
Solution Approach 1:
The same three physical contacts serve multiple functions across different operating phases. Each contact can be configured as either the supply contact or the sense contact depending on the current phase, allowing the sensor to achieve offset cancellation without adding extra contact terminals. This multi-functionality reduces the overall device complexity compared to using additional dedicated contacts for each phase.
Solution Approach 2:
The sensor employs dynamic reconfiguration of contact roles through time-varying switching controlled by clock phases. The supply and sense contacts are dynamically assigned to different physical contacts in each phase, allowing the system to adapt its measurement configuration. This dynamic approach enables offset cancellation through software or circuit-controlled phase switching rather than requiring complex hardware reconfiguration.
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 significantly reduces residual offset errors by several orders of magnitude, improving the accuracy and sensitivity of the sensor devices while maintaining high magnetic field detection capabilities.
Implementation Method 1
Hall sensors and sensing methods OFFSET CANCELLATION IN HALL SENSOR DEVICES BACKGROUND Magnetic field sensors, such as Hall sensors, are sensitive to magnetic fields but can suffer from offset error.
Data Source
AI summary
Embodiments relate to multi-contact sensor devices and operating methods thereof that can reduce or eliminate offset error. In embodiments, sensor devices can comprise three or more contacts, and multiple sensor devices can be combined. The sensor devices can comprise Hall sensor devices, such as vertical Hall devices, or other sensor types. Operating modes can be implemented for the multi-contact sensor devices which offer significant modifications of and improvements over conventional spinning current principles. In a first operating mode, the sensor is supplied with the same input current in all operating phases, with the output voltages of all operating cycles sensed and processed. In another operating mode, the sensor device is supplied with the same input voltage in all operating phases, the sense terminals are forced to constant potentials, and the currents flowing into or out of the sense terminals are sensed and processed.