Control device for a sensor system, sensor system, and method for transmitting signals in a sensor system

Abstract

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.

Description

Background technique [0001] To transmit data from peripheral sensors to the central control unit (ECU), current interfaces are used in some sensor systems, in particular passenger protection systems of motor vehicles; the current interfaces can basically be unidirectional or bidirectional. DE 10 2004 013 597 A1 shows such a sensor system with a control device and sensors connected via a unidirectional electrical connection, also referred to as PAS3 or PAS4. [0002] In such systems, the current supply is provided by a control unit as receiver, which is usually designed as a special ASIC and outputs an interface current consisting of a sensor static current (interface static current) and a sensor data current. Thus, the sensor modulates the sensor quiescent current based on the measurements of its sensor elements. [0003] For the case of a low-ohmic bus-to-ground short circuit, the receiver can be equipped with a short-circuit current limiting circuit. [0004] However, limi...

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Problems solved by technology

[0005] However, too high a short-circuit-limited interface current would limit the maximum possible power loss of the receiver and thus limit the supply capability of the voltage supply

[0006] Therefore, the number of sensors connected to the control device is often already limited by the fact that in the event of a short circuit, a very high total current is applied by the control device at the sensor interfaces of the receiver, which leads to a corresponding size

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