Vehicle Switch State Detection Circuit with Optocoupler Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current detection circuits for heavy-duty vehicles are complex, consume single-chip microcomputer resources, and fail to isolate external inputs, making it difficult to distinguish between closed and suspended states of high and low-level active switches.
Innovation Solution
A detection circuit incorporating an optocoupler circuit module, low-level and high-level active path modules, filtering and debouncing module, and transient suppression module, which uses an optocoupler, diodes, transistors, and capacitors to isolate and differentiate between switch states without occupying valuable microcomputer resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-level and low-level periodic inversion circuit is added to distinguish switch states, then the detection capability is improved, but the wiring difficulty increases and I/O port resources are occupied
Solution Approach 1:
The patent extracts the state detection function from the microcontroller's I/O ports by implementing a dedicated detection circuit at the input端. The detection circuit independently identifies high-level, low-level, and suspended states without requiring the microcontroller's I/O ports to participate in the detection process, thereby freeing up I/O resources and simplifying wiring.
Solution Approach 2:
The patent introduces an intermediary detection circuit that acts as a mediator between the external switch and the microcontroller. This detection circuit processes the switch state signals and provides standardized output to the microcontroller, eliminating the need for complex periodic inversion circuits and reducing wiring complexity.
2Measurement precision
If ADC resources are used to sample port voltage for distinguishing switch states, then the detection accuracy is improved, but the ADC resources are occupied and programming difficulty increases
Solution Approach 1:
The patent extracts the voltage sampling function from the ADC resource by implementing a dedicated voltage detection circuit that directly compares the port voltage against reference voltages using voltage comparators. This approach eliminates the need to occupy ADC resources while maintaining high detection accuracy through hardware-level voltage comparison.
Solution Approach 2:
The patent replaces the software-based ADC sampling method with a hardware-based voltage comparator circuit. This substitution eliminates the need for complex programming to implement periodic sampling and threshold judgment, as the voltage comparators automatically perform the detection and provide direct digital output signals.
3Measurement precision
If two comparators are used to convert analog quantity to digital TO level signal, then the state distinction capability is improved, but the PCB area increases due to larger comparator size
Solution Approach 1:
The patent implements a multi-functional detection circuit that can detect high-level, low-level, and suspended states using a single integrated circuit structure. The voltage comparators are configured to handle multiple detection scenarios simultaneously, eliminating the need for separate detection circuits for different switch types and reducing the overall PCB area.
Solution Approach 2:
The patent merges the detection functions for high-level active switches and low-level active switches into a single integrated detection circuit. By combining the voltage comparison and state identification functions into one unified circuit, the PCB area is significantly reduced compared to using separate comparator circuits for each switch type.
4Device complexity
If the detection circuit does not isolate external inputs, then the circuit simplicity is maintained, but the reliability decreases due to potential interference from strong voltages
Solution Approach 1:
The patent introduces an optocoupler as an intermediary isolation component between the external switch circuit and the microcontroller. The optocoupler provides electrical isolation while allowing signal transmission, effectively blocking strong voltage interference from affecting the microcontroller while maintaining circuit functionality.
Solution Approach 2:
The patent segments the detection circuit into isolated functional modules: the external switch interface, the voltage detection circuit, and the microcontroller interface. Each module is electrically isolated from the others, with the optocoupler providing galvanic isolation between the high-voltage external circuit and the low-voltage microcontroller, thereby improving reliability without significantly increasing 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
Effectively distinguishes between open, close, and suspension states of high and low-level active switches, isolating strong and weak voltages to meet the requirements of vehicle generalization and modular design, with improved resource efficiency and reduced programming complexity.
Implementation Method 1
an optocoupler circuit module, a low-level active path module, a high-level active path module
Implementation Method 2
an optocoupler, diodes, transistors, and capacitors to isolate and differentiate between switch states
Implementation Method 3
The low-level active path module includes a diode, an anode of the diode is an input terminal of the low-level active path module, and a cathode of the diode is an output terminal of the low-level active path module
Implementation Method 4
a filtering and debouncing module, a transient suppression module
Data Source
AI summary
A detection circuit for open, close and suspension states of a high and low level effective switch in a vehicle. The circuit includes an optocoupler circuit module, a low-level active path module, a high-level active path module, a filtering and debouncing module, a transient suppression module, and a wiring terminal. The optocoupler circuit module is connected to the low-level active path module, the high-level active path module and the low-level active path module are connected in parallel to the filtering and debouncing module, and the filtering and debouncing module is connected to the transient suppression module, and then connected to the external high-level active switch or low-level active switch through the wiring terminal. Whether it is a high-level active switch or a low-level active switch, the detection circuit can distinguish whether the switch is in the closed or suspended state, and the strong and weak voltages are isolated.