ECU Power Supply Switching for Crash Backup Continuity
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Solution Overview
Problem
Existing ECU power supply systems fail to ensure continuous and effective power delivery to protection devices during vehicle crashes, particularly when the vehicle battery disconnects, leading to incomplete or delayed deployment of safety features.
Innovation Solution
An ECU with power supply management that includes two switching elements, a first switching element before a diode connected to the vehicle battery and a second switching element before a diode connected to an energy reserve, prioritizing power from the vehicle battery until its voltage is lost, then switching to the energy reserve if necessary, using fast-reacting transistors like field effect transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diode is used to prevent reverse current flow from sub power supply to main power supply, then reverse current protection is achieved, but voltage drop occurs in the power supply line
Solution Approach 1:
The patent introduces a current mirror circuit as an intermediary mechanism between the main power supply and sub power supply. The current mirror detects current flow direction and activates switching elements to prevent reverse current, thereby protecting the system without relying on a diode that would cause continuous voltage drop. This intermediary mechanism provides protection only when needed (during reverse current conditions).
Solution Approach 2:
The patent replaces the static diode protection method with a dynamic control system using switching elements (MOSFETs) controlled by a current mirror circuit. The switching elements dynamically adjust their state based on current flow direction, enabling reverse current prevention only when necessary while maintaining low impedance paths during normal operation, thus minimizing voltage drop under normal conditions.
2Adaptability or versatility
If switching elements are added before diodes in power supply lines, then power supply switching capability is improved, but device complexity increases
Solution Approach 1:
The current mirror circuit serves multiple functions: it detects current direction, controls switching elements, and enables both normal power supply operation and reverse current protection. The switching elements (MOSFETs) also serve dual purposes as both power transmission path and controlled isolation mechanism. This multi-functionality reduces the need for separate dedicated components for each function.
Solution Approach 2:
The current mirror circuit automatically detects current flow direction and autonomously controls the switching elements without requiring external control signals or complex control logic. The system self-regulates based on the electrical conditions in the power supply lines, eliminating the need for additional control circuitry or microcontroller intervention.
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
Ensures timely and reliable power supply to protection devices, allowing for proper deployment of safety features like airbags and event data recorders, reducing the need for a large energy reserve and lowering production costs while ensuring redundancy.
Implementation Method 1
a diode placed in the electric connection to the vehicle battery and the electric connection to the energy reserve
Data Source
Figure 1
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Figure 4
AI summary
The invention relates to an electronic control unit (10) with a power supply management and to a method for power supply in an electronic control unit (10). The electronic control unit (10) is connected via an electric connection (6C) to a vehicle battery (6) and connected via an electric connection (7C) to an energy reserve (7) of the electronic control unit (10). The electronic control unit (10) controls a first switching element (13) which is positioned prior to a first diode (11) in the electric connection (6C) from the vehicle battery (6) to the control circuit (8). Additionally, the electronic control unit (10) controls a second switching element (14) positioned prior to the second diode (12) in the electric connection (7C) from the energy reserve (7) to the control circuit (8).