Resistor Ladder Switch Position Detection on One Input Terminal
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Solution Overview
Problem
Existing toggle switches require additional control ICs or replacement with larger input terminals when multiple switches are used, hindering device downsizing.
Innovation Solution
A switch device with a movable contact, fixed contacts, resistors, and a control unit that uses a single input terminal to determine multiple operation positions, allowing for downsizing by eliminating the need for additional control units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple toggle switches are connected to a control IC, then the switching functionality is provided, but the number of input terminals required increases, leading to increased substrate size
Solution Approach 1:
The patent applies multi-functionality by enabling a single input terminal to detect multiple switch positions (first position, second position, and intermediate position) through voltage level detection. The control IC universally handles different switch states by comparing detected voltages against reference levels, allowing one terminal to replace what would traditionally require multiple terminals for equivalent functionality.
Solution Approach 2:
The patent changes the parameter detection approach from discrete digital signals to continuous analog voltage levels. By detecting voltage variations at a single input terminal corresponding to different switch positions, the system transforms positional information into electrical parameter changes, enabling compact control IC design while maintaining full switching functionality.
2Adaptability or versatility
If additional control ICs are added to handle multiple switches, then the switching capacity increases, but the device size and complexity increase
Solution Approach 1:
The control IC is designed with universal voltage comparison capability that can identify multiple distinct switch positions through a single input terminal. This multi-functional detection mechanism allows one control IC to replace multiple control ICs, reducing overall device complexity while maintaining expanded switching capacity.
Solution Approach 2:
The patent merges multiple switch detection functions into a single control IC by implementing voltage level detection at one input terminal. The control IC combines reference voltage generation, voltage comparison, and position identification functions internally, consolidating what would require separate control units into a single integrated device.
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 switch device achieves substantial downsizing by utilizing a single input terminal for multiple operation positions, reducing the size of the control IC and substrate, and maintaining functionality without additional hardware or software measures.
Implementation Method 1
a control unit that comprises an input terminal connected to a first node between the fixed contact connected closest to the power supply and the resistor and determines the operation position of the operation unit based on voltage detected through the input terminal
Data Source
AI summary
A switch device includes an operation unit to receive an operation performed by a user, a movable contact that is connected to a ground circuit and moves according to an operation performed on the operation unit, plural fixed contacts whose state of connection to the movable contact is switched according to an operation position of the operation unit, plural resistors connected in series in such a manner that one end is connected to a power supply, another end is connected to one of the plural fixed contacts, and a node formed by connecting in series is connected to the remaining of the plural fixed contacts, and a control unit that includes an input terminal connected to a first node between the fixed contact connected closest to the power supply and the resistor and determines the operation position of the operation unit based on voltage detected through the input terminal.