Parallel Switch-Resistor Control Circuit for Fixed-Off Failure Sensing
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Solution Overview
Problem
Existing vehicle power control devices fail to detect switch failures effectively, leading to abnormal current flow and potential switch failure due to the lack of a reliable failure sensing mechanism.
Innovation Solution
A control device comprising a first series circuit with a switch and resistor, and a second series circuit with a switch and resistor, connected in parallel, which includes a voltage output circuit and a sensing unit to detect failures by analyzing voltage values between the resistors, allowing for the identification of switch and resistor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one semiconductor switch is turned on while the other is fixed to off due to failure, then the power feeding control function is maintained, but a large electric current flows through the operating switch causing excessive power consumption and potential failure
Solution Approach 1:
The control device performs preliminary failure detection by monitoring voltage across each semiconductor switch before normal operation. When a switch is detected to be fixed in the off state, the control device prevents abnormal current flow by controlling the other switch not to turn on, thereby avoiding excessive power consumption and potential damage.
Solution Approach 2:
The control device continuously monitors the voltage across each semiconductor switch and uses this feedback information to detect failures. When abnormal voltage indicating a fixed-off failure is detected, the control device adjusts its operation to prevent the other switch from turning on, thereby preventing abnormal current flow and excessive power consumption.
2Device complexity
If no failure detection mechanism is implemented, then the device complexity is reduced, but switch failures cannot be sensed leading to abnormal current flow and potential damage
Solution Approach 1:
The semiconductor switches themselves provide failure detection information through their voltage characteristics. By monitoring the voltage across each switch, the control device can detect failures without requiring separate detection circuits for each switch, thereby maintaining simple device structure while achieving reliable failure detection.
3Reliability
If voltage monitoring is implemented to detect switch failures, then failure detection capability is improved, but the device complexity increases due to additional sensing circuits
Solution Approach 1:
The voltage monitoring circuit serves multiple functions: it detects switch failures by monitoring voltage across switches, and it also provides information about the operational state of the switches. This multi-functionality allows reliable failure detection without requiring separate dedicated detection circuits for each switch.
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, preventing abnormal current flow and switch damage by sensing voltage changes, thereby ensuring reliable operation and reducing power consumption.
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
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.