Bridge Sensor Error Check via Polarity Biasing
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Solution Overview
Problem
Current methods for detecting hardware faults in bridge sensors, such as magnetic sensors, often require duplication of the sensor, leading to increased silicon surface area and complexity, and are not effective in reducing false error detections due to offset and physical parameter variations.
Innovation Solution
A method and device that bias a first contact pair of the bridge sensor in multiple directions, measuring output signals at different times, and combining these measurements to reduce the impact of offsets and physical parameter changes, allowing for sensitive error detection without duplication, using at least three measurements taken when biasing the same contact pair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual modular redundancy is used to detect hardware faults, then reliability is improved, but device complexity and silicon surface area increase
Solution Approach 1:
The patent uses a simplified copy approach by duplicating only the error detection logic and measurement sequence rather than the entire sensor. The same bridge sensor is used, but measurements are taken multiple times with reversed bias polarity to create redundant data for error detection, avoiding full sensor duplication
Solution Approach 2:
The measurement system serves dual purposes: normal operation measurements and error detection measurements. The same hardware infrastructure is used for both functional operation and self-diagnosis, eliminating the need for separate dedicated error detection hardware
2Measurement precision
If multiple measurements are combined to reduce offset impact, then measurement precision is improved, but false error detections increase due to physical parameter variations
Solution Approach 1:
The patent applies counterbalancing by taking measurements with reversed bias polarity. The offset errors present in normal measurements are counterweighted by corresponding measurements taken with opposite polarity, allowing offset cancellation while preserving the true sensor response to physical parameters
Solution Approach 2:
The patent selectively combines only those measurements that were taken during normal operational biasing, skipping measurements taken during error-check sequences. This rushes through the error detection process using pre-existing operational data, avoiding the need to wait for additional dedicated error check measurements
Data Source
AI summary
A method for detecting an error in a bridge sensor which is adapted for measuring a physical parameter. The method comprises biasing a first contact pair of the bridge sensor at least two times in a first direction and at least one time in a second direction opposite to the first direction; while biasing the first contact pair, measuring an output signal on a different contact pair of the bridge sensor, thus obtaining at least three output measurements which are representative for the physical parameter and which are separated by time intervals; combining the output measurements to obtain an output value which is indicative for an error in the bridge sensor, wherein the output measurements which are combined are only those output measurements which are measured when biasing the first contact pair.