Parallel Switch Current Sensing for Fixed-Off Fault Detection
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Solution Overview
Problem
Existing vehicle control devices fail to effectively sense and manage failures in semiconductor switches, leading to potential overheating and further failures when one switch is fixed off, causing excessive current flow through the other switch.
Innovation Solution
A control device with a first and second series circuit, each comprising a switch and a resistor, connected in parallel, which includes a voltage output circuit to detect voltage changes and sense failures based on threshold values, allowing for timely notification and prevention of overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one semiconductor switch is fixed to off, then the system can detect the failure, but excessive current flows through the other switch causing overheating and potential failure
Solution Approach 1:
The patent applies preliminary action by detecting switch failures before they cause overheating. The control device continuously monitors the on/off state of semiconductor switches and proactively identifies when a switch is fixed to off, allowing the system to take preventive measures before excessive current causes temperature rise and potential failure of the remaining switch.
Solution Approach 2:
The patent implements feedback by continuously monitoring the state of semiconductor switches and using this information to control power feeding. The control device receives feedback signals indicating whether switches are properly on or off, and adjusts power delivery accordingly to prevent overheating conditions while maintaining reliable operation.
2Measurement precision
If the control device continuously monitors switch states, then failure detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies self-service by having the semiconductor switches themselves generate the monitoring signals. Each switch's on/off state naturally produces detectable electrical signals that the control device can read, eliminating the need for separate physical sensors or monitoring hardware. The existing circuit operation provides the feedback information needed for failure detection.
Solution Approach 2:
The control device performs multiple functions using a single integrated system. It not only controls power feeding to the load but also simultaneously monitors switch states, detects failures, and prevents overheating. This multi-functionality reduces overall system complexity compared to having separate dedicated monitoring and control devices.
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 enables the detection and notification of switch failures, preventing overheating and prolonging the lifespan of semiconductor switches by accurately sensing voltage changes and adjusting operations accordingly.
Implementation Method 1
a voltage output circuit configured to output a voltage value that corresponds to a voltage value between two ends of the first resistor; and a sensing unit configured to sense, when the instruction unit has given an instruction to turn on the first switch and the second switch, any occurrence of a failure in at least one of the first switch, the second switch, the first resistor, and the second resistor based on the voltage value output by the voltage output circuit
Data Source
AI summary
A control device includes a first series circuit and a second series circuit. In the first series circuit, a first switch and a first resistor are connected in series to each other. In the second series circuit, a second switch and a second resistor are connected in series to each other. A current detection circuit outputs a voltage value that corresponds to a voltage value between two ends of the first resistor. When an instruction to turn on the first switch and the second switch has been given, a control unit senses any occurrence of a failure in at least one of the first switch, the second switch, the first resistor, and the second resistor, based on the voltage value output by the current detection circuit.