Vehicle Load Control Circuit for Dual-Voltage Bus Overvoltage Protection
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Solution Overview
Problem
Existing overvoltage protection methods for vehicles with multiple on-board networks operating at different voltages are costly and inefficient, risking damage to electrical components due to voltage differences.
Innovation Solution
A control device with a reference voltage generating unit, signal voltage limiting unit, and supply voltage generating unit, utilizing MOSFETs and diodes to limit bus signals to a safe reference voltage, protecting components from overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical isolators or specialized fault-tolerant components are used for overvoltage protection, then component reliability is improved, but material costs and device complexity increase
Solution Approach 1:
The patent introduces a potential equalization unit as an intermediary component between the high-voltage and low-voltage on-board networks. This unit includes a first switching element connected between the high-voltage line and the communication interface, and a second switching element connected between the low-voltage line and the communication interface. The potential equalization unit actively monitors and equalizes voltage potentials between the two networks, preventing overvoltage damage to the communication interface while using simpler, more cost-effective components compared to optical isolators or specialized fault-tolerant components.
2Reliability
If optical isolators or specialized fault-tolerant components are used for overvoltage protection, then component reliability is improved, but material costs increase
Solution Approach 1:
The patent introduces a potential equalization unit as an intermediary component between the high-voltage and low-voltage on-board networks. This unit includes a first switching element connected between the high-voltage line and the communication interface, and a second switching element connected between the low-voltage line and the communication interface. The potential equalization unit actively monitors and equalizes voltage potentials between the two networks, preventing overvoltage damage to the communication interface while using simpler, more cost-effective components compared to optical isolators or specialized fault-tolerant components.
3Device complexity
If standard communication interfaces are used without overvoltage protection, then device complexity is reduced, but component reliability deteriorates due to overvoltage damage risk
Solution Approach 1:
The patent implements preliminary protective action by introducing a potential equalization unit that proactively monitors and equalizes voltage potentials between the high-voltage and low-voltage on-board networks before overvoltage conditions can damage the communication interface. The switching elements are configured to automatically activate when voltage differences exceed safe thresholds, preventing overvoltage damage in advance rather than relying on reactive protection mechanisms.
Data Source
AI summary
A control device for a load in a vehicle with a first on-board network operated using a first voltage and a second on-board network operated using a second voltage, wherein the first voltage is greater than the second voltage, the control device comprising a reference voltage generating unit configured to provide a reference voltage; a signal voltage limiting unit configured to receive a bus signal from the second on-board network und to limit a voltage of the bus signal to at most the reference voltage; a bus signal receiving unit configured to receive the voltage-limited bus signal from the signal voltage limiting unit; and a supply voltage generating unit configured to generate, according to the voltage-limited bus signal, a supply voltage for the load based on the first voltage.