Magnetic Position Sensor Circuit With Multi-Threshold Current Coding
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Solution Overview
Problem
Two-wire position sensors can only detect two mechanical positions due to their two supply current states, necessitating the use of two separate ICs to detect three positions, which increases complexity and tolerance errors.
Innovation Solution
A single IC-based position sensor circuit with configurable logic and multiple current sink codes, allowing detection of more than two positions by defining at least three current sink codes and using a threshold circuit to compare magnetic field conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate ICs are used to detect three positions, then the number of detectable positions increases from two to three, but the device complexity increases and tolerance errors accumulate
Solution Approach 1:
The patent merges the functionality of two separate ICs into a single IC by integrating multiple current sink codes (I_OFF1, I_OFF2, I_ON) and configurable logic circuits within one device. This allows the single IC to output multiple current states (I_ON + I_OFF1, I_ON + I_OFF2, I_ON + I_ON) corresponding to three different positions, thereby detecting three positions without requiring two separate ICs and reducing overall system complexity
Solution Approach 2:
The single IC is designed with universal functionality to perform multiple detection tasks. By incorporating selectable current sink codes and configurable logic, the IC can generate multiple distinct current states from a single device, enabling it to detect multiple positions (three or more) that previously required multiple separate ICs, thus achieving multi-functionality within a single component
2Adaptability or versatility
If two separate ICs are used to detect three positions, then more positions can be detected, but tolerance errors accumulate and measurement precision decreases
Solution Approach 1:
By combining multiple current sink codes and comparison logic into a single IC, the patent eliminates the accumulation of tolerance errors that would occur when using two separate ICs. The single IC ensures consistent tolerance characteristics across all three detectable positions, as all comparison operations are performed within the same device with unified reference standards, thereby maintaining high measurement precision while detecting multiple positions
3Device complexity
If a single IC is used with two current states, then the device complexity is low, but the number of detectable positions is limited to two
Solution Approach 1:
The patent applies dynamics by making the current sink codes configurable and selectable based on detected position. The IC dynamically switches between different current states (I_OFF1, I_OFF2, I_ON) depending on the detected magnetic field conditions, allowing a single IC to adaptively represent multiple positions through configurable logic and multiple current codes, thereby increasing detectable positions from two to three or more while maintaining single-IC simplicity
Solution Approach 2:
The patent changes the parameter of current sink code selection to enable multiple position detection. By providing multiple selectable current sink codes (I_OFF1, I_OFF2, I_ON) and using configurable logic to select among them based on comparison results, the single IC can output different current states corresponding to different positions, thus expanding the number of detectable positions while keeping the device complexity low
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
Enables precise and reliable detection of multiple positions without the complexity of dual ICs, simplifying design and enhancing accuracy through flexible threshold settings and current source control.
Implementation Method 1
By measuring the strength of a magnetic field generated by one or more magnetic object(s) at various locations, the position or orientation of the object(s) relative to the sensor elements can be determined
Implementation Method 2
The release point B RP is always smaller value than the B OP (502). In this way hysteresis is brought to the system, which makes the sensor circuit more stable when operating around the operating point B OP (502)
Data Source
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AI summary
The present invention relates to a position sensor circuit designed to detect a magnetic field and to provide an output indicative of its characteristics. The circuit includes a sensor (20) for generating an output signal corresponding to the magnetic field, a signal conditioning circuit (30) arranged to receive said output signal and to output a version of said output signal, a threshold circuit (40) arranged to define at least two pairs of thresholds and to store at least three current sink codes, and a comparison circuit (60) for comparing the version of the output signal against these thresholds to produce a comparison circuit output signal. A configurable logic circuit (80) is employed to select one of the at least three current sink codes based on the comparison circuit output signal. A current source circuit (90) is arranged to receive the selected current sink code and to output a current with a current value corresponding to the selected current sink code. This configuration allows for the determination of the magnetic field's polarity or strength, with the potential for detecting faulty states through specific threshold pairings.