Circuit Fault Detection with Resistor Value Correction
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Solution Overview
Problem
Existing circuit fault detection systems face challenges in accurately detecting overcurrent and disconnection faults due to individual differences in resistor values, leading to incorrect threshold settings and potential failure to detect faults when digital values reach the upper or lower limits of the AD conversion range.
Innovation Solution
A circuit fault detection apparatus incorporating an AD conversion circuit, a corrector, a first determination device, and a second determination device, which corrects measurement values and compares them with both uncorrected and corrected threshold values to enhance fault detection precision, accounting for variations in resistor values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold value is used for fault detection, then the device complexity is reduced, but the measurement precision deteriorates due to individual differences in resistor values
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction coefficients in a lookup table during the manufacturing process. These correction coefficients compensate for individual resistor variations, allowing the system to maintain high measurement precision without complex real-time calculations during operation.
Solution Approach 2:
The patent changes the parameter approach by transitioning from a single fixed threshold to multiple correction coefficients stored in a lookup table. Each coefficient corresponds to specific resistor value ranges, allowing the system to adapt to individual component variations while maintaining simple comparison logic.
2Adaptability or versatility
If the AD conversion range is extended to cover all possible measurement values, then the adaptability is improved, but the measurement precision deteriorates when values reach the upper or lower limits
Solution Approach 1:
The patent applies preliminary action by pre-calculating correction coefficients for different resistor value ranges and storing them in a lookup table. This allows the system to handle various measurement scenarios within the AD conversion range while maintaining precision through appropriate coefficient selection based on actual resistor values.
3Measurement precision
If correction coefficients are calculated and stored for every possible resistor value, then the measurement precision is improved, but the loss of substance increases due to memory usage
Solution Approach 1:
The patent changes the parameter approach by discretizing resistor value ranges into intervals, with one correction coefficient stored for each interval boundary. This reduces memory requirements from storing coefficients for every possible resistor value to storing coefficients only for range boundaries, while still achieving accurate compensation through linear interpolation or direct lookup.
Data Source
AI summary
A circuit fault detection apparatus includes an AD conversion circuit, a corrector, first and second determination devices, and a fault detector. The AD conversion circuit detects a voltage corresponding to a current or a voltage applied to the circuit fault detection element, and converts the voltage to a digital value. The corrector corrects a measurement value to a corrected measurement value. The first determination device determines whether or not the electric circuit has the fault, based on a comparison between an uncorrected measurement value and an uncorrected threshold value. The second determination device determines whether the electric circuit has the fault, based on a comparison between the corrected measurement value and a corrected threshold value. The fault detector detects the fault in the electric circuit, based on a condition that at least one of the first or second determination devices determines that the electric circuit has the fault.