Linear Hall Sensor Digital Offset Compensation Without Chopping Delay
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Solution Overview
Problem
Conventional Hall effect devices suffer from zero-point offset errors due to manufacturing asymmetries and mechanical stress, which current spinning methods fail to completely eliminate.
Innovation Solution
A magnetic sensor circuit with a digital signal processing unit that includes a delay removal circuitry, capable of generating a non-delayed, offset-compensated digital output signal by mathematically operating on digital signal components within a single chopping phase, effectively canceling out offset errors without introducing significant delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current spinning methods are used to reduce offset errors, then measurement precision is improved, but loss of time increases due to lengthy chopping phases
Solution Approach 1:
The patent replaces the conventional analog current spinning method with a digital signal processing approach. Instead of physically switching current directions in the Hall plate, the invention uses digital mathematical operations on ADC output signals to achieve offset cancellation. This substitution eliminates the need for lengthy chopping phases while maintaining offset error reduction capability.
Solution Approach 2:
The patent performs offset compensation calculations using previously acquired signal components within the same chopping phase. By utilizing stored digital signal components and performing mathematical operations (addition, subtraction, averaging) on these pre-acquired signals, the system achieves offset cancellation without waiting for complete chopping cycles, thereby reducing time loss.
2Device complexity
If conventional Hall effect devices are used, then device complexity is low, but measurement precision deteriorates due to zero point offset errors
Solution Approach 1:
The patent introduces a digital signal processing unit as an intermediary between the Hall plate and the output. This unit receives the analog output signal from the conventional Hall plate, converts it to digital form via ADC, and performs mathematical operations to cancel offset errors. The intermediary digital processing layer maintains the simplicity of the physical Hall device while dramatically improving measurement precision.
3Measurement precision
If lengthy chopping phases are used for offset compensation, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent replaces the time-consuming mechanical chopping process with rapid digital signal processing. Instead of requiring long chopping phases to accumulate sufficient signal for offset cancellation, the invention uses digital mathematical operations that can be performed instantly on ADC output signals, thereby maintaining high detection speed while achieving accurate offset compensation.
Solution Approach 2:
The patent skips the traditional lengthy chopping phase by performing offset compensation calculations within the same chopping phase using stored digital signal components. By rushing through the compensation calculation using pre-acquired signal data and digital mathematical operations, the system achieves offset cancellation without the time penalty of conventional methods, thereby improving productivity.
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 offset errors in magnetic sensor outputs, enhancing the accuracy and speed of magnetic field detection by eliminating the need for lengthy chopping phases, thus improving performance in high-speed applications.
Implementation Method 1
Hall effect devices are solid state electron devices that operate in response to a magnetic field based upon the Hall effect principle, a phenomenon by which a voltage differential is generated across an electrically conducting body in the presence of a magnetic field
Data Source
AI summary
One embodiment of the present invention relates to a magnetic sensor circuit having a magnetic field sensor device configured to generate a digital signal proportional to an applied magnetic field. An analog-to-digital converter converts the analog signal to a digital signal that is provided to a digital signal processing unit, which is configured to digitally track the analog output signal. The digital tracking unit comprises a delay removal circuitry configured to generate a plurality of digital signal component corresponding to a chopping phase. A non-delayed offset compensated digital output signal may be generated within the chopping phase by mathematically operating upon (e.g., adding or subtracting) the plurality of digital signal components, generated by the delay removal circuitry.