Switch Position Detection Using External Resistor Reference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switch detection methods for electrical devices require specific types of microcontrollers with internal or external voltage references, which are not always feasible or efficient, especially for ensuring redundant safety and restart protection.
Innovation Solution
An apparatus and method utilizing a microcomputer device that calculates the switch position from the voltage drop between circuit nodes, with a switched-mode power supply providing voltage, allowing for switch position detection independent of voltage amplitude and using detection voltage analysis to determine switch state, potentially with redundant 'two-channel' validation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microcontroller with internal or external voltage reference is used to detect switch position, then the switch position can be determined by comparing voltage to reference voltage, but the device complexity increases and specific microcontroller types are required
Solution Approach 1:
The invention extracts the voltage reference function from the microcontroller and implements it externally using a resistor connected to a defined voltage potential. This allows the use of simpler microcomputer devices without internal voltage references, reducing device complexity while maintaining detection accuracy
Solution Approach 2:
The external resistor serves as a universal voltage reference that can be used with any microcomputer device regardless of whether it has internal voltage reference capabilities. This universal approach eliminates the need for specific microcontroller types, making the solution applicable to a broader range of devices
2Reliability
If redundant switch detection is provided to increase safety level, then operational safety improves, but the device complexity and cost increase
Solution Approach 1:
The invention combines the switch position detection function with the existing power supply circuitry by using the same circuit nodes and components. The resistor serves both as a pull-up/pull-down element for the switch detection and as part of the power supply network, eliminating the need for separate redundant detection circuits while maintaining safety
Solution Approach 2:
The detection circuit uses the same external resistor and voltage reference for both normal operation and safety-critical switch position detection. This multi-functional approach provides redundant safety detection without requiring additional dedicated safety circuitry, reducing overall device complexity
Data Source
AI summary
An apparatus for detecting a switch position includes a first circuit node and a second circuit node configured to connect the apparatus to an AC electric voltage. The apparatus further includes a switch connected between the first circuit node and a third circuit node, and a resistor connected between the first circuit node and the third circuit node. The apparatus also includes a microcomputer device, and a switched-mode power supply apparatus connected between the second circuit node and the third circuit node. The switched-mode power supply apparatus is configured to provide a supply voltage to the microcomputer device at the third circuit node. The microcomputer device is configured to calculate a position of the switch from an electric detection voltage dropped between the third circuit node and the second circuit node.