Series Switch Circuit Failure Detection
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Solution Overview
Problem
Existing switch devices cannot detect malfunctions such as disconnection or short circuits due to a switch's inability to return to its initial state, leading to increased costs and weight from additional terminals and cables when redundancy is implemented.
Innovation Solution
A switch circuit with two series-connected circuits, each having a unique resistor configuration that changes based on the switch's conduction state, allowing for failure detection without increasing the number of output terminals or cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two switches are provided for redundancy to detect malfunctions, then the reliability of failure detection is improved, but the number of terminals and cables increases, leading to increased cost and weight
Solution Approach 1:
The patent combines two switch circuits into a single integrated unit where the first and second switches are connected in series within the same housing. The external cable connects to only one terminal, yet both switches can be monitored for failures. This merging reduces the number of external terminals and cables while maintaining the ability to detect malfunctions in either switch through resistance value measurements.
2Reliability
If two switches are provided for redundancy to detect malfunctions, then the reliability of failure detection is improved, but the weight of the switch device increases
Solution Approach 1:
By merging both switches and their detection circuits into a single compact housing with shared terminals and cables, the patent reduces the overall weight compared to having separate redundant switch devices. The integrated design allows both switches to be monitored through a single external connection point, eliminating the need for additional heavy cabling and terminal structures.
3Measurement precision
If resistance values are measured to detect external cable failures, then the detection capability is improved, but the ability to distinguish between switch failures and cable failures becomes difficult
Solution Approach 1:
The patent segments the resistance measurement approach by creating distinct measurement paths: one path through the switches (first and second switches in series) and another path through the external cable. By measuring resistance between specific terminals and comparing expected versus actual values, the system can identify whether a failure occurs in the switch portion or the cable portion of the circuit, enabling precise failure localization without increasing overall system complexity.
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
Enables the detection of switch failures and malfunctions without adding output terminals or cables, reducing costs and weight while maintaining effective operation.
Implementation Method 1
measuring a resistance value between a first terminal and a second terminal; determining, based on the resistance value, a malfunction of the first switch, a malfunction of the second switch, or disconnection or short circuit of an external cable
Data Source
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AI summary
A switch circuit includes a first circuit including a first switch, and a second circuit including a second switch. The first circuit and the second circuit are connected in series. The first circuit has a circuit configuration in which a combination of resistors in a signal path between output terminals of the first circuit differs depending on the electrical conduction state of the first switch. The second circuit has a circuit configuration in which a combination of resistors in a signal path between output terminals of the second circuit differs depending on the electrical conduction state of the second switch.