Dual-Switch Power Supply Cutoff for Short-Circuit Loads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply control devices for vehicles fail to effectively stop power supply to a load when a short-circuit failure occurs, leading to unnecessary power consumption.
Innovation Solution
A power supply control device with upstream and downstream switches, where a processing unit monitors current flow and instructs the switches to switch off the second switch if current is detected flowing through the first switch during an intended OFF instruction, ensuring power cessation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single switch is used to control power supply to a load, then the device complexity is reduced, but the reliability of stopping power supply during short-circuit failure deteriorates
Solution Approach 1:
The power supply control is segmented into two independent switches (first switch and second switch) positioned at different locations in the circuit. This segmentation allows the system to isolate faults more effectively - if one switch fails to stop current during a short-circuit failure, the other switch can still interrupt the power supply path, thereby resolving the reliability issue without excessive complexity
Solution Approach 2:
The control device performs preliminary detection of current flow state before attempting to switch off the power supply. By detecting whether current is still flowing after a switch-off instruction, the system can identify short-circuit failures and take alternative actions (such as controlling the second switch) to ensure power supply is stopped, preventing unnecessary power consumption
2Reliability
If current flow monitoring is continuously performed, then the reliability of detecting short-circuit failure is improved, but the energy consumption increases
Solution Approach 1:
The processing unit performs current flow detection at specific periodic intervals rather than continuously. The detection is triggered at key moments - when a switch-off instruction is given and when checking if the switch has properly interrupted current. This periodic detection approach maintains reliable short-circuit failure detection while significantly reducing energy consumption compared to continuous monitoring
Data Source
AI summary
An ECU controls the supply of power to a load. An upstream switch and a downstream switch are respectively arranged upstream and downstream of the load in a current path of the flow of current through the load. A control unit of a microcomputer determines whether or not current is flowing through the upstream switch while an instruction to switch OFF the upstream switch has been given. If it was determined that current is flowing through the upstream switch, the control unit gives an instruction to switch OFF the downstream switch.