Vehicle Switch State Detection Circuit with Intermittent Monitoring
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Solution Overview
Problem
Conventional vehicle switch control methods increase current consumption when the engine is turned on, and existing technologies do not effectively control current flow in switches based on engine state.
Innovation Solution
A switch state detection circuit with multiple switch current sources and an integrated circuit that determines engine on/off state, operating in normal mode with intermittent current supply when the engine is on and in sleep mode with longer intermittent supply when the engine is off, to reduce current consumption and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the monitoring signal is always output to the vehicle switches in normal mode, then the switch states can be detected continuously, but the current consumption increases
Solution Approach 1:
The patent applies periodic action by switching between normal mode (continuous monitoring) and sleep mode (intermittent monitoring) based on engine state. In normal mode, monitoring signals are continuously output to detect switch states reliably. In sleep mode, monitoring signals are output only at predetermined intervals to reduce current consumption. This periodic switching resolves the contradiction between maintaining reliable detection and reducing energy usage.
Solution Approach 2:
The patent implements dynamics by making the monitoring signal output dynamic rather than static. The system automatically adjusts between continuous output (normal mode) and intermittent output (sleep mode) based on real-time engine state detection. This dynamic adaptation allows the system to optimize the balance between detection reliability and current consumption according to actual operating conditions.
2Use of energy by stationary object
If the processing unit such as CPU or MPU is switched to sleep state when engine is stopped, then power consumption is reduced, but the switch state detection function must be performed by a separate device
Solution Approach 1:
The patent applies universality by designing an integrated circuit that performs multiple functions: it detects engine state, determines operating mode (normal or sleep), generates monitoring signals, and detects switch states. This multi-functional integrated circuit eliminates the need for separate detection devices, resolving the contradiction between reducing power consumption and maintaining system simplicity.
3Adaptability or versatility
If the number of electronic devices in vehicle is increased, then the vehicle functionality is enhanced, but the power consumption must be reduced regardless of engine on/off state
Solution Approach 1:
The patent applies periodic action by implementing intermittent monitoring in sleep mode at predetermined intervals. This allows the system to support enhanced vehicle functionality through multiple electronic devices while reducing power consumption by not continuously monitoring all switches. The periodic monitoring maintains essential detection capabilities with lower energy usage.
Data Source
AI summary
Provided is an integrated circuit (41) that operates in normal mode or sleep mode corresponding to the on/off state of a vehicle engine. On the basis of information of setting data information stored in an internal register (42) and information of the on/off state of the vehicle engine from an MPU (50), the integrated circuit (41) generates monitoring signals (INZ0 to INZ7), monitoring signals (INA0 to INA7), and monitoring signals (INB0 to INB5). These monitoring signals enables to monitor states of a head light switch (11), a door switch (12), and a window switch (13). As the switch state monitoring method, intermittent operation or constant monitoring operation is performed.