Automotive Power Management Switching Between Battery and Cigarette Lighter
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Solution Overview
Problem
Electronic devices that draw power from an automobile's main battery continue to drain it even when the vehicle is not running, leading to rapid battery discharge since they do not differentiate between engine-on and engine-off states.
Innovation Solution
A power management system that uses a switch to control power intake from multiple sources, closing the switch when the engine is on and opening it after a predefined time if the engine is off, ensuring the device stops drawing power from the main battery when the vehicle is not in use, utilizing a terminal block for the main battery and a power connector for alternative power sources like a cigarette lighter receptacle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the device draws power directly from the main battery, then the device can operate continuously, but the main battery drains quickly when the automobile is not running
Solution Approach 1:
The system dynamically switches between power sources based on the ignition state. When ignition is on, the device draws power from the main battery; when ignition is off, it switches to the cigarette lighter receptacle or shuts down. This dynamic adaptation resolves the contradiction by making power intake conditional rather than continuous.
Solution Approach 2:
The cigarette lighter receptacle serves as an intermediary power source between the main battery and the device. It allows the device to operate when the main battery should be preserved (engine off), acting as a buffer that prevents direct drainage of the main battery while maintaining device functionality.
2Ease of operation
If the device remains powered on when the automobile is off, then the device is always available, but unnecessary power is consumed from the main battery
Solution Approach 1:
The device availability is made dynamic rather than static. It adapts to the automobile's operational state by remaining available when the engine is running and shutting down or switching power sources when the engine is off, thus avoiding unnecessary power consumption while maintaining availability when needed.
Solution Approach 2:
The system uses the ignition state as feedback to control power intake. The detection of whether the engine is on or off provides feedback that triggers appropriate power management actions, ensuring the device only consumes power from the main battery when the automobile is actively running.
3Loss of energy
If the device monitors ignition state and switches power sources, then battery drain is prevented, but device complexity increases
Solution Approach 1:
The cigarette lighter receptacle acts as a simple intermediary component that requires minimal control logic. By leveraging this existing automobile feature as a power source, the system achieves battery protection without requiring complex power management circuitry, thus resolving the contradiction between energy conservation and system simplicity.
Data Source
AI summary
Methods and systems for managing power supply at a device. The device is capable of receiving power via a plurality of power inputs. The device first determines whether a first condition is satisfied. A first switch is maintained in a closed position if the first condition is satisfied. When the first switch is in a closed position, the device is capable of receiving power from a first power supply. Alternatively, when the first condition is not satisfied, the device determines whether or not a second condition is satisfied. If the second condition is satisfied, the first switch is maintained to be in a closed position. If the second condition is not satisfied, the first switch is opened after a predefined time period.