Vehicle Power Supply Switching Sequence to Prevent Ignition Surge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vehicle power supply systems, when the ignition switch is turned on, a surge can occur due to the change in switch states, potentially leading to switch failure when power is supplied from the main power supply to the load.
Innovation Solution
A power supply control device with a first switch between the main power supply and the load, and a second switch between a sub-power supply and the load, controlled by a controller that manages the on/off states of these switches. The controller turns off the first switch and turns on the second switch when the ignition switch is turned off, and vice versa when the ignition switch is turned on, to prevent surge-induced switch failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first switch is turned on to supply electric power from the main power supply to the load when the ignition switch is turned on, then the load can operate during the ignition-on period, but a surge may occur causing switch failure
Solution Approach 1:
The controller turns off the first switch before turning on the second switch when the ignition switch is turned on. This preliminary action of opening the main power supply switch before connecting the sub-power supply prevents surge occurrence by ensuring no current flow conflict occurs during the power supply transition.
Solution Approach 2:
The controller acts as an intermediary that coordinates the switching sequence between the first and second switches. By controlling the timing and sequence of switch operations, the controller mediates the power supply transition to avoid direct conflict between main power supply and sub-power supply connections, preventing surge-induced switch failure.
2Adaptability or versatility
If the sub-power supply is used to supply electric power to the load during the ignition-off period, then the load can operate during the ignition-off period, but switching between power supplies may cause surge
Solution Approach 1:
The controller turns off the first switch before turning on the second switch when transitioning to ignition-off mode. This preliminary disconnection of the main power supply prevents surge by ensuring the main power supply is disconnected before the sub-power supply is connected, eliminating current flow conflict during the power supply transition.
Solution Approach 2:
The system periodically switches between main power supply and sub-power supply based on the ignition switch state. The controller implements periodic switching sequences where the first switch is turned off and the second switch is turned on in a controlled manner, allowing the load to operate during both ignition-on and ignition-off periods while preventing surge through proper sequencing.
Data Source
AI summary
A power supply control device includes: a first switch coupled between a main power supply and a load; a second switch coupled between a sub-power supply and the load; and a controller configured to perform on/off control of the first switch and the second switch. The controller is configured to: turn off the first switch and turn on the second switch, in response to an ignition switch being turned off; and turn off the second switch and then turn on the first switch, in response to the ignition switch being turned on.