Semiconductor Main Relay Voltage Limiting for Brake ECU Overvoltage
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Solution Overview
Problem
Modern motor vehicle brake systems face issues with electronic control units shutting down due to power supply voltage fluctuations, particularly overvoltages, which can occur during delivery or operation, leading to a loss of control functions like ABS and ESP.
Innovation Solution
A circuit arrangement with dynamically acting voltage limiters for semiconductor driver stages, integrating a high-side MOSFET transistor into a voltage regulator, allowing the main semiconductor relay to switch to a linear control mode during overvoltages and limiting voltage at loads to prevent thermal destruction, while ensuring continuous operation of valve and booster functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common semiconductor main relay is used to switch off consumers in the electronics unit, then safety function is improved, but the control unit shuts down completely during power supply voltage fluctuations
Solution Approach 1:
The patent segments the power control system into two independent parts: a high-side driver that can be dynamically limited during overvoltages, and a low-side driver that remains operational. This segmentation allows the control unit to maintain critical functions (ABS, ESP) while protecting against voltage fluctuations, resolving the contradiction between safety shutdown function and continuous operational reliability
Solution Approach 2:
The patent implements dynamic voltage limiting for the high-side driver that activates only during overvoltage conditions. The circuit continuously monitors supply voltage and dynamically adjusts the high-side driver's operation, allowing full power control during normal conditions while providing protective limiting during voltage spikes. This dynamic approach maintains productivity during normal operation while ensuring safety during abnormal conditions
2Object-affected harmful factors
If the main relay switches off during overvoltage to protect electronics, then electronic protection is improved, but valve control and brake booster functions are interrupted
Solution Approach 1:
The patent divides the driver stages into high-side and low-side independent control paths. The high-side driver is subject to dynamic voltage limiting that protects against overvoltages, while the low-side driver operates independently without being affected by the high-side limitations. This segmentation ensures that critical brake functions (valve control, brake booster) continue operating during voltage fluctuations while electronics are protected from damage
Solution Approach 2:
The patent introduces a voltage monitoring and control mechanism that acts as an intermediary between the power supply and the driver stages. This intermediary continuously monitors supply voltage and selectively limits the high-side driver's power delivery during overvoltage conditions while maintaining normal operation during acceptable voltage ranges, thus protecting electronics without interrupting critical brake functions
3Reliability
If a dynamically acting voltage limiter is provided for driver stages, then continuous operation during voltage fluctuations is achieved, but device complexity increases
Solution Approach 1:
The patent merges the voltage limiting function with the existing high-side driver circuitry. The dynamic voltage limiting is implemented by modifying the high-side driver's control characteristics rather than adding a completely separate limiting circuit. This integration approach achieves continuous operation during voltage fluctuations while minimizing the increase in device complexity by reusing existing circuit components and control structures
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
The solution ensures that brake system control functions remain operational during voltage fluctuations, preventing complete power supply interruption and allowing for safe reactivation only through vehicle ignition, thus maintaining system reliability and safety.
Implementation Method 1
limiting voltage at loads to prevent thermal destruction
Data Source
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AI summary
The invention relates to an electronic circuit comprising at least one semiconductor main relay (1) connected to at least one semiconductor driver stage (3) in order to control loads (4). The semiconductor main relay (1) connects the loads (4) and the drivers (3) to a voltage supply in such a way that they can be disconnected, and the semiconductor main relay(s) (1) is/are operated in certain situations as voltage regulators and in other situations as semiconductor switches. The invention also relates to the use of the circuit arrangement in a motor vehicle braking system, especially a driving dynamics regulation system, or a system for chassis regulation, or in an electronic control system for vehicle safety systems.