Dynamic Short-Circuit Current Limiting for Vehicle Sensor Systems
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Solution Overview
Problem
In occupant protection systems, existing unidirectional current interfaces face challenges with power loss and limited sensor connectivity due to high short-circuit currents, which can lead to component overloading and reduced power availability when multiple sensors experience short circuits.
Innovation Solution
A time-variable short-circuit current limitation system is implemented, where the current is initially limited to a high value during a short circuit to prevent interference with normal operation, then reduced to a lower value after a predetermined period, ensuring power supply to other sensors and reducing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the short-circuit current is limited to a high value to prevent interference with normal operation, then normal operation is maintained, but power loss increases and power supply availability decreases
Solution Approach 1:
The patent applies dynamic short-circuit current limitation by switching between two different current limits based on operational state. During normal operation, a first higher current limit is applied to maintain reliability. Upon detecting a short circuit, a second lower current limit is applied to reduce power loss. This dynamic adjustment resolves the contradiction by adapting the current limit to the actual operational condition.
Solution Approach 2:
The patent implements periodic action through time-based current limitation stages. A first current limit is applied during an initial period after short-circuit detection, then a second current limit is applied in a subsequent period. This temporal segmentation allows the system to balance between maintaining operation and reducing power loss at different time phases of the short-circuit event.
2Adaptability or versatility
If multiple sensors are connected to a control device, then system functionality increases, but power supply overload risk increases due to cumulative short-circuit currents
Solution Approach 1:
The patent enables multiple sensors to be connected by dynamically adjusting the current limit based on the number of active sensors and detected short circuits. When short circuits are detected among multiple sensors, the control device switches to a lower current limit stage, preventing power supply overload while maintaining connectivity for non-faulty sensors. This resolves the contradiction between system versatility and power supply capacity.
3Reliability
If a fixed high current limit is applied during short circuits, then normal operation is maintained, but component destruction risk increases due to sustained high currents
Solution Approach 1:
The patent applies periodic action through staged current limitation over time. A first higher current limit is applied during an initial time period to maintain operation continuity. After this first period expires, a second lower current limit is applied to prevent component destruction from sustained high currents. This temporal staging resolves the contradiction between maintaining operation and preventing damage.
Solution Approach 2:
The patent implements beforehand cushioning by preparing a second lower current limit stage that activates after the first period. This pre-planned reduction in current limit serves as protective cushioning against potential component destruction from prolonged high current exposure, while the initial higher limit provides temporary operation continuity.
Data Source
Figure 1~2
AI summary
The invention relates to a control device (2) for a sensor system (1), particularly as part of an occupant protection system of a vehicle, wherein the control device (2) comprises at least: one connection device (9) for connecting a data connection (4), particularly a unidirectional bus, having at least two lines (4a, 4b) as a current interface to at least one sensor (3), wherein through the data connection (4) the connection device (9) receives signals (14) generated by the sensor (3) through current modulation of an interface current (I), wherein the control device (2) comprises a current-limiting circuit (10), which limits a short-circuit current (I_2, I_3) on at least one line (4a, 4b) of the data connection (4) in the event of a short circuit, wherein the current-limiting circuit (10) limits the short-circuit current (I_2, I_3) in a temporally varying manner. The sensor system and the method for transmitting signals in the sensor system are also provided.