Inductive Position Sensor Integrated Circuit Star Point Fault Detection
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Solution Overview
Problem
Inductive sensors in star configurations face challenges in detecting imminent failures due to inaccessible star points, limiting effective fault detection and weakness identification, especially in harsh environments where delicate electronics are not feasible.
Innovation Solution
An integrated circuit with sensing circuitry, current sources and sinks, and an evaluator to detect failures and weaknesses by applying current through loops of sensing coils and verifying detection signals, allowing for early identification of connection issues without requiring access to the star point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the star point is accessed for fault detection, then fault detection capability is improved, but device complexity and routing restrictions increase
Solution Approach 1:
The patent introduces an intermediary measurement method that uses voltage comparisons at accessible terminals to indirectly detect faults in the otherwise inaccessible star point configuration. Instead of directly accessing the star point, the system uses comparators to measure voltage differences between terminals, which indirectly reveals star point connection status.
Solution Approach 2:
The patent replaces the physical access requirement (mechanical/electrical connection to star point) with an electrical measurement system using voltage dividers and comparators. The fault detection is achieved through electrical signal processing rather than direct physical access to the star point.
2Measurement precision
If more I/O pins are integrated for fault detection, then detection precision is improved, but device complexity increases
Solution Approach 1:
The patent makes existing terminals serve multiple functions: they are used for both normal sensor operation and for fault detection measurements. The same terminals that connect the sensing coils are also used as measurement points for detecting connection faults, eliminating the need for dedicated test pins.
Solution Approach 2:
The patent combines the fault detection circuitry with the existing sensor terminals and star point configuration. The voltage divider networks and comparators are integrated into the existing terminal structure, merging measurement functions with the sensor's operational infrastructure.
3Ease of operation
If voltage-based detection is used, then ease of operation is improved, but detection precision for weak connections deteriorates
Solution Approach 1:
The patent changes the measurement parameter from simple voltage level detection to voltage difference comparison. By using comparators to measure the difference between two voltage dividers rather than absolute voltages, the system becomes sensitive to small resistance changes that indicate weak connections, while maintaining operational simplicity.
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 reliable detection of open or weakened connections in inductive sensor systems, preventing silent failures and ensuring sensor reliability in safety-critical applications by generating detection signals and evaluating impedance variations, thus minimizing errors and ensuring timely maintenance.
Implementation Method 1
a current source and a current sink coupled to respectively a first and a second of said terminals, such that upon supply of current from the current source a current is established through the loop external to the integrated circuit and a detection signal is generated
Data Source
AI summary
An integrated circuit is provided for use in a sensor system having a plurality of sensing coils arranged in a star configuration coupled to terminals of an integrated circuit, such that a first and a second terminal are connected external to the integrated circuit via a loop including a first and a second sensing coil in the plurality of sensing coils. The integrated circuit includes: sensing circuitry for evaluation of sense signals received from the sensing coils via said terminals; a current source and a current sink coupled to respectively a first and a second of said terminals, such that upon supply of current from the current source a current is established through the loop external to the integrated circuit and a detection signal is generated; and an evaluator for evaluating one of more detection signals to detect failure and/or weakness within said loop.