Dynamic Range Electrical Isolation Detection Circuit
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Solution Overview
Problem
Existing methods for detecting electrical isolation between a voltage bus terminal and ground in vehicles require costly, bulky, or complicated circuitry to accommodate a wide range of leakage currents, which can indicate electrical shorts or degraded isolation.
Innovation Solution
A system and method that apply a first current to a bus terminal, detect the corresponding voltage level, and use a compensator to adjust the voltage range, allowing an analog-to-digital converter to accurately measure the isolation level, thereby enhancing the dynamic range of leakage current sensing without increasing complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior art approaches are used to accommodate extensive range of leakage current, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The system dynamically adjusts the measurement range by switching between different gain settings in the transimpedance amplifier based on the detected leakage current magnitude. This allows the circuit to adapt to varying leakage levels without requiring multiple fixed-range measurement circuits, thereby maintaining measurement precision across an extensive dynamic range while avoiding the complexity of multiple parallel measurement paths.
Solution Approach 2:
The patent changes the operational parameters of the measurement circuit by adjusting the transimpedance amplifier gain and analog-to-digital converter scaling factors based on the detected leakage current level. This parameter adaptation allows the same hardware circuit to accurately measure both small and large leakage currents by modifying its transfer function, eliminating the need for complex multi-range circuitry.
2Measurement precision
If prior art approaches are used to accommodate extensive range of leakage current, then measurement precision is improved, but device cost increases
Solution Approach 1:
The measurement circuit is designed to perform multiple functions across different leakage current ranges using a single transimpedance amplifier and analog-to-digital converter. By implementing software-based range selection and gain adjustment, the same hardware components serve multiple measurement purposes, eliminating the need for expensive dedicated circuits for each leakage range and reducing overall manufacturing cost.
Solution Approach 2:
Instead of implementing multiple physical measurement circuits for different leakage ranges, the patent creates a virtual copy of the measurement function through software control of the amplifier gain and ADC scaling. This digital replication allows the system to simulate multiple measurement ranges using a single physical circuit, significantly reducing component count and manufacturing cost while maintaining measurement precision.
3Measurement precision
If prior art approaches are used to accommodate extensive range of leakage current, then measurement precision is improved, but device bulkiness increases
Solution Approach 1:
The system uses dynamic gain adjustment in the transimpedance amplifier to accommodate varying leakage current magnitudes within a compact circuit. By switching between pre-defined gain settings based on the detected current level, the circuit maintains measurement precision across an extensive dynamic range without requiring multiple parallel amplifier stages, thereby minimizing the circuit volume.
Solution Approach 2:
The patent combines the functions of multiple measurement ranges into a single integrated transimpedance amplifier and analog-to-digital converter system. By merging what would traditionally require separate circuits for different leakage ranges into one unified measurement path with software-controlled gain adjustment, the design achieves extensive measurement capability in a compact footprint, reducing overall device bulkiness.
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
This approach enables effective detection of electrical isolation over a broad range of leakage currents, reducing the need for costly or bulky circuitry and providing reliable detection of degraded isolation or short circuits.
Implementation Method 1
A compensator or data processing system is configured to compensate for a range in the first level, or the corresponding observed voltage, associated with the detected first level by applying a corresponding compensating voltage level to a resistive network
Data Source
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AI summary
A bus terminal (21) is isolated from ground potential during normal operation of the vehicle. A first current is applied to the bus terminal (21). A current level detector (50) is arranged to detect a first level of the first current, or a corresponding observed voltage level, that exists or flows from the bus terminal (21) to ground. A compensator (79) is configured to compensate for a range in the detected first level by applying a corresponding compensating voltage level to a first resistor (e.g., in resistive network 75) coupled to the current level detector (50). An electronic data processor (62) is capable of estimating a first isolation level between the bus terminal (21) and ground (99) based on the detected first level.