Differential Power Detection Circuit with Resistor Verification
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Solution Overview
Problem
Existing power bus fault detection circuits using the Differential Power method face reliability issues due to inaccuracies in fault current identification and the inability to verify the functionality of certain components, particularly the resistor, leading to potential false negatives in fault detection.
Innovation Solution
A circuit design incorporating multiple resistors and signal conditioners that compare voltage and current differences across these components to set thresholds, with a control module determining a differential power condition based on these comparisons, and an optional stimulation signal to verify circuit functionality, enhancing reliability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single resistor is used to detect differential power conditions, then the circuit complexity is reduced, but the reliability decreases due to inability to verify resistor functionality
Solution Approach 1:
The single resistor detection function is segmented into multiple resistors (first resistor, second resistor, third resistor) with distinct roles. The first and second resistors are used for differential power detection, while the third resistor serves as a reference for functionality verification through BITE, allowing reliability improvement without excessive complexity
Solution Approach 2:
A stimulation signal is introduced as an intermediary to verify the functionality of the resistors and signal conditioner. This STIM signal allows the system to actively test whether components are functioning correctly, resolving the reliability issue by providing a verification mechanism
2Reliability
If multiple signal conditioners are used to process transducer signals, then the reliability is improved through redundancy, but the manufacturing cost increases
Solution Approach 1:
The signal conditioning function is segmented and distributed across multiple signal conditioners, each handling specific signals. This segmentation provides redundancy so that if one signal conditioner fails, others can continue operating, improving reliability while maintaining manageable manufacturing costs through modular design
3Measurement precision
If the detection threshold is set low to detect small faults, then the measurement precision is improved, but the false positive rate increases
Solution Approach 1:
The system uses multiple detection paths with different threshold levels. While one path may use lower thresholds for high sensitivity, other paths provide confirmation, ensuring that detections meet multiple criteria before triggering an alarm, thus reducing false positives while maintaining precision
4Reliability
If BITE is implemented to verify circuit functionality, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The BITE functionality is merged with the existing differential power detection circuitry. The same resistors and signal conditioners used for fault detection are also utilized for self-testing through stimulation signals, combining detection and verification functions into a unified system that improves reliability without adding separate complex BITE hardware
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
The improved circuit design allows for early detection of faults while maintaining high reliability, reducing the risk of false negatives and improving accuracy by minimizing errors and providing redundancy, thus ensuring timely fault detection before damage occurs.
Implementation Method 1
A voltage across the third resistor is proportional to a difference between the first current and the second current
Data Source
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AI summary
A method of determining a differential power condition includes comparing a voltage across a resistor (34) to a first threshold. The voltage across the resistor is proportional to a difference between a first current and a second current. The method also includes comparing a difference between the first current and the second current to a second threshold. A differential power condition is determined in response to the voltage across the resistor exceeding the first threshold, the difference exceeding the second threshold, or both.