DC Voltage Threshold Detector Circuit for Aircraft Power Bus
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Solution Overview
Problem
Existing systems for detecting unusually high voltage on a DC power bus in aircraft electrical systems are complex and large, lacking a compact and efficient solution to communicate voltage threshold crossings to various systems.
Innovation Solution
A voltage detection circuit with a scaling resistor network and comparator that communicates with an optical isolation device to send signals based on the input line voltage relative to a threshold voltage, allowing for efficient detection and isolation of voltage threshold crossings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing voltage detection systems are used to detect high voltage thresholds on DC power bus, then voltage threshold detection is achieved, but the system becomes complex and large in size
Solution Approach 1:
The patent extracts only the essential function of voltage threshold detection from complex existing systems. By using a simple voltage divider network to scale down the high voltage to a manageable level, and a comparator to detect when the scaled voltage exceeds a threshold, the system achieves reliable detection without the complexity and large size of conventional solutions.
Solution Approach 2:
The patent introduces an optical isolation device as an intermediary between the voltage detection circuit and the output signal. This optical isolator transfers the detection signal optically, providing electrical isolation while maintaining signal transmission. This resolves the contradiction by enabling reliable threshold detection while simplifying the overall system architecture and reducing complexity.
2Reliability
If voltage detection circuit is isolated from power bus using optical isolation, then electrical isolation is achieved, but signal transmission complexity increases
Solution Approach 1:
The optical isolation device serves as an intermediary that simplifies signal transmission while providing electrical isolation. The device converts electrical signals to optical signals and back, creating clean electrical isolation between the power bus side and the output side. This approach actually reduces overall complexity compared to trying to achieve isolation through complex filtering or isolation transformers.
Solution Approach 2:
The patent replaces traditional electrical isolation methods (such as transformers or complex RC networks) with an optical isolation system. By using light instead of electrical fields for signal transmission across the isolation barrier, the system achieves superior electrical isolation with simpler circuitry and fewer components.
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 solution provides a compact and scalable method for detecting high voltage thresholds on a DC power bus, enabling efficient communication of voltage status to aircraft systems while isolating the output from the input, allowing for easy adjustment and operation across a wide voltage range.
Implementation Method 1
an output of the comparator communicates a signal to an optical isolation device
Data Source
AI summary
A voltage detection circuit comprises a tap to be connected to a positive line and a return tap to be connected to a return line on a power supply. The potential difference between the positive line and the return line is the input line voltage. A scaling resistor network scales down the input line voltage to be indicative of a voltage on the input line. The scaled voltage is connected to an input for a comparator. A reference voltage is supplied to the comparator. The reference voltage supplied to the comparator is indicative of a threshold voltage at which an output of the circuit changes states. An output of the comparator communicates a signal to an optical isolation device when the input line voltage is below the threshold voltage to turn the optical isolation device on and send a signal to an output of the optical isolation device. The optical isolation device is not turned on if the input line voltage exceeds the threshold voltage. A DC power bus incorporating the voltage detection circuit, along with an aircraft electrical system incorporating the DC power bus are also disclosed and claimed.