阅读说明：本技术 用于车辆的传感器组件 (Sensor assembly for a vehicle ) 是由 J·维尔特 M·凯格尔 于 2020-03-24 设计创作，主要内容包括：本发明涉及一种用于车辆的传感器组件(1),具有用于检测测量变量的传感器元件(WSS)和至少两个控制器(ECU1、ECU2),控制器分别具有测量电路(MS1、MS2)和电源(VB1、VB2),其中传感器元件(WSS)的第一端子(WSS1)与至少两个控制器(ECU1、ECU2)中的第一控制器(ECU1)的电源(VB1)连接,并且传感器元件(WSS)的第二端子(WSS2)经由至少两个控制器(ECU1、ECU2)中的第二控制器(ECU2)的测量电路(MS1、MS2)与接地端子(GND)连接,其中流经传感器元件(WSS)的传感器电流(Is)利用关于所检测的测量变量的信息进行调制,其中第一控制器(ECU1)的测量电路(MS1)评估在电源(VB1)和传感器元件(WSS)之间的高侧路径中所检测的传感器电流(Is),并且第二控制器(ECU2)的第二测量电路(MS2)同时评估在传感器元件(WSS)和接地端子(GND)之间的低侧路径中所检测的传感器电流(Is),其中第一紧急保护电路(20A)与低侧路径并行布置并且监控在传感器元件(WSS)的第二端子(WSS2)处的电压降(U12),其中当电压降(U12)达到预定的击穿电压值(UK)时,第一紧急保护电路(20A)为传感器元件(WSS)提供替代的低侧路径并且接收传感器电流(Is),使得至少第一测量电路(MS1)能够继续评估所检测的传感器电流(Is),其中第一紧急保护电路(20A)还将电压降(U12)降低到小于击穿电压值(UK)的保持电压值(UH)。(The invention relates to a sensor arrangement (1) for a vehicle, having a sensor element (WSS) for detecting a measurement variable and having at least two controllers (ECU1, ECU2) which each have a measurement circuit (MS1, MS2) and a power supply (VB1, VB2), wherein a first terminal (WSS1) of the sensor element (WSS) Is connected to the power supply (VB1) of a first controller (ECU1) of the at least two controllers (ECU1, ECU2) and a second terminal (WSS2) of the sensor element (WSS) Is connected to a ground terminal (GND) via a measurement circuit (MS1, MS2) of a second controller (ECU2) of the at least two controllers (ECU1, ECU2), wherein a sensor current (Is) flowing through the sensor element (WSS) Is modulated with information about the measured variable, wherein a measurement circuit (MS1) of the first controller (ECU1) evaluates a high sensor current (IS) in a sensor path (WSS) between the power supply (VB1) and a sensor element (WSS1), and a second measurement circuit (MS2) of the second controller (ECU2) simultaneously evaluates the sensor current (Is) detected in the low-side path between the sensor element (WSS) and the ground terminal (GND), wherein a first emergency protection circuit (20A) is arranged in parallel with the low-side path and monitors a voltage drop (U12) at a second terminal (WSS2) of the sensor element (WSS), wherein the first emergency protection circuit (20A) provides an alternative low-side path for the sensor element (WSS) and receives the sensor current (Is) when the voltage drop (U12) reaches a predetermined breakdown voltage value (UK), enabling at least the first measurement circuit (MS1) to continue evaluating the detected sensor current (Is), wherein the first emergency protection circuit (20A) further reduces the voltage drop (U12) to a holding voltage value (UH) that is less than the breakdown voltage value (UK).)

1. A sensor assembly (1) for a vehicle, having a sensor element (WSS) for detecting a measured variable and at least two controllers (ECU1, ECU2), the at least two controllers (ECU1, ECU2) having a measuring circuit (MS1, MS2) and a power supply (VB1, VB2), respectively,

wherein a first terminal (WSS1) of the sensor element (WSS) is connected with a power supply (VB1) of a first controller (ECU1) of the at least two controllers (ECU1, ECU2) and a second terminal (WSS2) of the sensor element (WSS) is connected with a ground terminal (GND) via a measurement circuit (MS1, MS2) of a second controller (ECU2) of the at least two controllers (ECU1, ECU2),

wherein a sensor current (Is) flowing through the sensor element (WSS) Is modulated with information about the measured variable detected,

wherein the measurement circuit (MS1) of the first controller (ECU1) evaluates a sensor current (Is) detected in a high-side path between the power supply (VB1) and the sensor element (WSS), and the second measurement circuit (MS2) of the second controller (ECU2) simultaneously evaluates a sensor current (Is) detected in a low-side path between the sensor element (WSS) and the ground terminal (GND),

Wherein a first emergency protection circuit (20A) is arranged in parallel with the low-side path and monitors a voltage drop (U12) at a second terminal (WSS2) of the sensor element (WSS),

wherein the first emergency protection circuit (20A) provides an alternative low-side path for the sensor element (WSS) and receives the sensor current (Is) when the voltage drop (U12) reaches a predetermined breakdown voltage value (UK) such that at least a first measurement circuit (MS1) can continue evaluating the detected sensor current (Is),

wherein the first emergency protection circuit (20A) further reduces the voltage drop (U12) to a holding voltage value (UH) that is less than the breakdown voltage value (UK).

2. Sensor assembly (1) according to claim 1, characterized in that the first emergency protection circuit (20A) automatically re-opens the alternative low-side path when the voltage drop (U12) due to an external event drops below an off-voltage value (ABS) which is smaller than the hold-voltage value (UH).

3. Sensor assembly (1) according to claim 1 or 2, characterized in that a second emergency protection circuit (20B) Is arranged in parallel with the high-side path and monitors a voltage drop (U12) at the first terminal (WSS1) of the sensor element (WSS), wherein the second emergency protection circuit (20B) provides an alternative high-side path for the sensor element (WSS) and receives the sensor current (Is) when the voltage drop (U12) reaches a predetermined breakdown voltage value (UK), such that at least the second measurement circuit (MS2) can continue to evaluate the detected sensor current (Is), wherein the second emergency protection circuit (20B) also reduces the voltage drop (U12) to a holding voltage value (UH) which Is smaller than the breakdown voltage value (UK).

4. Sensor assembly (1) according to claim 3, characterized in that the second emergency protection circuit (20B) automatically re-opens the alternative high-side path when the voltage drop (U12) due to an external event drops below an off-voltage value (ABS) which is smaller than the holding voltage value (UH).

5. Sensor assembly (1) according to one of the claims 1 to 4, characterized in that each of the emergency protection circuits (20A, 20B) comprises a voltage detector (22) and a current sink (24), wherein the voltage detector (22) drives the current sink (24) in order to establish a current path between the terminals (A1, A2) of the respective emergency protection circuit (20A, 20B).

6. Sensor assembly (1) according to claim 5, characterized in that the voltage detector (22) detects a voltage drop (U12) between the first terminal (A1) and the second terminal (A2) of the respective emergency protection circuit (20A, 20B) and drives the current sink (24) when the detected voltage drop (U12) reaches a predetermined breakdown voltage value (UK).

7. The sensor assembly (1) of claim 6, wherein the current sink (24) sets the voltage drop (U12) to a predetermined hold voltage value (UH) and receives the sensor current (Is).

8. Sensor assembly (1) according to claim 7, characterized in that the voltage detector (22) in combination with an overvoltage protector (uv) drives the current sink (24) when the voltage drop (U12) rises, so that the sensor current (Is) drops to a minimum current or Is completely switched off.

9. The sensor assembly (1) according to one of claims 5 to 8, characterized in that the voltage detector (22) terminates the drive of the current sink (24) and interrupts the current path again when the detected voltage drop (U12) is below a predetermined shut-off voltage value (ABS).

10. Sensor assembly (1) according to one of claims 1 to 9, characterized in that the sensor element (WSS) detects a number of revolutions and/or a rotational speed and/or a pressure and/or a temperature as a measured variable.

11. Sensor assembly (1) according to one of claims 1 to 10, characterized in that a plurality of sensor elements (WSS) are provided, which are each arranged at one measuring point.

12. Sensor assembly (1) according to claim 11, characterized in that the measuring points are each assigned to a wheel, wherein the corresponding sensor element (WSS) detects at least one revolution and/or rotational speed of the respective wheel.

13. Sensor assembly (1) according to one of claims 1 to 12, characterized in that a current sensor (30) detects a sensor current (Is) in the high-side path and splits off a portion (Is/n) of the sensor current (Is) and supplies this portion of the sensor current as a measurement current (IM1) of the first measurement circuit (MS1) of the first controller (ECU1), wherein the second measurement circuit (ECU2) of the second controller (ECU2) receives and evaluates the sensor current (Is) directly as a second measurement current (IM 2).

14. Sensor assembly (1) according to one of the claims 1 to 13, characterized in that a switching device (30) connects the first terminal (WSS1) of the sensor element (WSS) with a first power supply (VB1) and/or a second power supply (VB2), wherein the switching device (30) automatically connects the first terminal (WSS1) of the sensor element (WSS) with the other power supply (VB2, VB1) in case of a failure of the connected power supply (VB1, VB 2).

15. Sensor assembly (1) according to claim 14, characterized in that the current sensor (10) and the switching device (30) are combined in an interconnect module (40) which is implemented as an ASIC module.

Technical Field

The present invention relates to a sensor assembly for a vehicle according to the preamble of independent claim 1.

Background

Sensor assemblies for vehicles are known from the prior art, which each have a wheel sensor with at least one sensor element for each wheel. The individual wheel sensors are usually connected via a two-wire twisted pair to a controller for a vehicle brake system, which performs, for example, ABS, ESP, ASR and/or hill-hold functions (ABS: anti-lock brake system, ESP: electronic stability program, ASR: drive anti-skid control). Typically, a first terminal of the at least one sensor element is connected to a power supply via the controller (high side path) and a second terminal of the at least one sensor element is connected to ground via the controller (low side path). The sensor current flowing through the at least one sensor element is modulated with information about the number of revolutions and/or the rotational speed of the respective wheel, wherein the evaluation and control unit of the controller evaluates the sensor current detected between the at least one sensor element and the ground.

DE 102016222628 a1 discloses a sensor arrangement with a sensor for detecting a measurement variable, comprising: a first evaluation unit having a first measuring resistor, to which a sensor signal of the sensor, which signal represents the measured variable, is fed to generate a measuring voltage drop; a second evaluation unit with a second measuring resistance, to which a sensor signal of the sensor representing the measured variable is fed to generate a measuring voltage drop; a first voltage source connected to the first evaluation unit; a second voltage source connected to the second evaluation unit; and a switching device which is connected to the sensor and is designed in such a way that, in the event of a failure of one evaluation unit, a measurement voltage drop can be generated across the measurement resistance of the other evaluation unit. Furthermore, the sensor is connected on the voltage side via a first measuring resistor to a first voltage source and on the ground side via a second measuring resistor to ground. In this case, a first diode-zener diode combination is connected in parallel with the first measuring resistor and a second diode-zener diode combination is connected in parallel with the second measuring resistor, wherein the first and second diode-zener diode combinations are each designed to have a breakdown voltage which is greater than the measuring voltage drop, so that in the event of a failure of the evaluation unit the relevant diode-zener diode combination can be caused to break down. Furthermore, a further first diode-zener diode combination may be provided, which is arranged between the sensor and the second voltage source. Furthermore, one end of a second diode-zener diode combination can be connected to the ground terminal of the second evaluation unit, and a further second diode-zener diode combination can be connected to the ground terminal of the first evaluation unit.

Disclosure of Invention

The advantage of a sensor arrangement for a vehicle having the features of independent claim 1 is that: the first emergency protection circuit monitors the low-side path and provides an alternative low-side path for the sensor element without current detection in case of a failure of the low-side path, so that the at least one first measurement circuit can continue to evaluate the detected sensor current. The first emergency protection circuit is activated when the voltage drop at the second measurement terminal of the sensor element exceeds a breakdown voltage value, which may be preset, for example, in the range from 2.0V to 4.0V. The activated first emergency protection circuit limits the voltage drop at the second measurement terminal of the sensor element to a holding voltage value in the range of about 0.8V to 1.5V and is able to withstand sensor currents of up to 50 mA. The emergency protection circuit of the emergency protection circuit according to the invention therefore has a significantly smaller voltage drop in the active state at similar load currents than a pure zener diode structure.

Embodiments of the invention provide a sensor unit for a vehicle, comprising a sensor element for detecting a measurement variable and at least two controllers, each having a measurement circuit and a power supply. The first terminal of the sensor element is connected to a power supply of a first controller of the at least two controllers, and the second terminal of the sensor element is connected to a ground terminal via a measurement circuit of a second controller of the at least two controllers. The sensor current flowing through the sensor element is modulated with information about the measured variable detected, wherein the measuring circuit of the first controller evaluates the sensor current detected in the high-side path between the power supply and the sensor element, and the second measuring circuit of the second controller simultaneously evaluates the sensor current detected in the low-side path between the sensor element and the ground connection. Furthermore, a first emergency protection circuit is arranged in parallel with the low-side path and monitors a voltage drop at the second terminal of the sensor element. The first emergency protection circuit provides an alternative low-side path for the sensor element and receives the sensor current when the voltage drop reaches a predetermined breakdown voltage value, so that at least the first measurement circuit can continue to evaluate the detected sensor current. In addition, the first emergency protection circuit reduces the voltage drop to a holding voltage value that is less than the breakdown voltage value.

Furthermore, such a sensor assembly for a vehicle has the following advantages: the sensor signals of the individual sensor elements are provided via taps between the power supply and the sensor elements in the first controller (high-side path) and via taps between the sensor elements in the second controller and ground (low-side path), so that they can be evaluated simultaneously by the two evaluation and control units. For this purpose, a first evaluation and measurement circuit of the first controller evaluates the sensor current detected in the high-side path, and a second evaluation and measurement circuit of the second controller simultaneously evaluates the sensor current detected in the low-side path. The use of only one simple sensor element per measuring point, the sensor signals of which are evaluated redundantly by the two controllers, results in a considerable cost reduction with approximately the same reliability of the redundancy evaluation compared to the use of two sensor elements per measuring point, since the sensor signals of all measuring points are evaluated in both controllers and the probability of failure of the sensor elements is low.

In general, an embodiment of the sensor assembly according to the invention may comprise a plurality of sensor elements which are arranged distributed in the vehicle at respective measuring points. Thus, embodiments of the sensor assembly herein may preferably be used in a vehicle braking system. In such a brake system, the measuring points can be assigned to one wheel each, for example, wherein the respective sensor element can detect at least one revolution and/or rotational speed of the assigned wheel. Of course, the sensor element may also be arranged at other measuring points in the vehicle. Furthermore, the sensor element can also detect other measured variables, such as temperature, pressure, etc.

An evaluation and control unit is understood here to be a circuit which processes or evaluates the detected sensor signals. The evaluation and control unit can have an interface which can be constructed on the basis of hardware and/or software. In a hardware-based configuration, the interface can be, for example, a part of a so-called ASIC system that contains the various functions of the evaluation and control unit. It is also possible that the interface is an integrated circuit of its own or is at least partly composed of discrete components. In a software-based configuration, the interface may be, for example, a software module that is present on the microcontroller together with other software modules. Also advantageous is a computer program product with a program code which is stored on a machine-readable carrier, such as a semiconductor memory, a hard disk memory or an optical memory, and which is used to carry out the evaluation when the evaluation and control unit runs the program.

In this context, a controller is understood to be an electrical device, such as a brake controller, which can be combined with a hydraulic brake system to perform various brake functions, such as ABS, ESP, ASR and/or hill-hold functions (ABS: anti-lock brake system, ESP: electronic stability program, ASR: drive anti-skid control). In this case, the two controllers can perform different braking functions in normal operation. In the event of a failure of one of the controllers, provision can be made for the other controller to take over the braking function of the failed controller.

A sensor element is understood here to be an electrical component which detects a physical variable or a change in a physical variable directly or indirectly in the assigned wheel region and preferably converts it into an electrical sensor signal. This can be done, for example, by the transmission and/or reception of sound waves and/or electromagnetic waves and/or by magnetic fields or changes in magnetic fields. Optical sensor elements may be used, for example optical plates and/or fluorescent surfaces and/or semiconductors, for example infrared sensor elements, which detect the impact or intensity, wavelength, frequency, angle, etc. of the received waves. Acoustic sensor elements, such as ultrasonic sensor elements and/or high-frequency sensor elements and/or radar sensor elements and/or sensor elements that respond to a magnetic field, such as hall sensor elements and/or magnetoresistive sensor elements and/or inductive sensor elements, which register a change in the magnetic field, for example, by means of a voltage generated by magnetic induction, are likewise conceivable.

The sensor arrangement for a vehicle specified in independent claim 1 can be advantageously modified by the measures and refinements listed in the dependent claims.

It is particularly advantageous if the first emergency protection circuit can automatically disconnect the alternative low-side path again if the voltage drop falls below a shut-off voltage value that is smaller than the holding voltage value as a result of an external event. For example, a drop in voltage drop may be caused by the initial low-side path having been reactivated and available again.

In an advantageous embodiment of the sensor arrangement, a second emergency protection circuit, which functions in a manner corresponding to the first emergency protection circuit, can be arranged in parallel with the high-side path and monitors the voltage drop at the first terminal of the sensor element. In this case, the second emergency protection circuit can provide an alternative high-side path for the sensor element and receive the sensor current when the voltage drop reaches the predetermined breakdown voltage value, so that at least the second measuring circuit can continue to evaluate the detected sensor current. In addition, the second emergency protection circuit reduces the voltage drop to a holding voltage value that is less than the breakdown voltage value. Furthermore, the second emergency protection circuit may automatically disconnect the alternative high side path again if the voltage drop falls below a shutdown voltage value that is lower than the holding voltage value due to an external event. For example, the off-voltage value may be preset in the range of 0.4V to 0.7V.

In a further advantageous embodiment of the sensor arrangement, the respective emergency protection circuit can comprise a voltage detector and a current sink. In this case, the voltage detector drives a current sink in order to establish a current path between the terminals of the respective emergency protection circuit. Further, the voltage detector may detect a voltage drop between the first terminal and the second terminal of the respective emergency protection circuit and drive the current sink when the detected voltage drop reaches a predetermined breakdown voltage value. In addition, the current sink may set the voltage drop across the transistor to a predetermined holding voltage value and receive the sensor current.

In a further advantageous embodiment of the sensor arrangement, the voltage detector can be combined with an overvoltage protection device to drive the current sink when the voltage drop rises, so that the sensor current can be reduced to a minimum current or completely switched off. The current sink is thereby advantageously protected against excessive currents or excessive total power losses, which could otherwise lead to damage to the current sink and the corresponding emergency protection circuit.

In a further advantageous embodiment of the sensor arrangement, the voltage detector can terminate the drive of the current sink and interrupt the current path again when the detected voltage drop falls below a predetermined switch-off voltage value.

In a further advantageous embodiment of the sensor arrangement, the current sensor can detect the sensor current in the high-side path and tap off a portion of the sensor current and supply it as the first measurement current to the first measurement circuit of the first controller. In this case, the second measuring circuit of the second controller can receive and evaluate the sensor current directly as the second measuring current. The current sensor can, for example, circulate into the current path and tap off a portion of the sensor current and pass the remaining sensor current to the sensor element. Thereby, the sensor current flowing into the first terminal of the corresponding sensor element is measured and an equivalent but significantly smaller portion of the sensor current is passed to the first measurement circuit. Thereby, power consumption in the first controller can be reduced.

In a further advantageous embodiment of the sensor arrangement, the switching device can connect the first terminal of the sensor element to the first power source and/or the second power source, wherein the switching device can automatically connect the first terminal of the sensor element to the further power source in the event of a failure of the connected power source. Furthermore, the current sensor and the switching device may be combined in an interconnect module, which may be implemented as an ASIC module.

Drawings

Embodiments of the invention are illustrated in the drawings and are explained in detail in the following description. In the drawings, the same reference numerals denote parts or elements performing the same or similar functions. Wherein:

fig. 1 shows a schematic block diagram of a first embodiment of a sensor assembly for a vehicle according to the present invention.

Fig. 2 shows a schematic block diagram of a second embodiment of a sensor assembly for a vehicle according to the present invention.

Fig. 3 shows a schematic block diagram of a third embodiment of a sensor assembly for a vehicle according to the present invention.

Fig. 4 shows a schematic block diagram of a fourth embodiment of a sensor assembly for a vehicle according to the present invention.

Fig. 5 shows a schematic block diagram of one embodiment of the emergency protection circuit for a sensor assembly of a vehicle according to the invention in fig. 1 to 4.

Fig. 6 shows a circuit diagram of the emergency protection circuit in fig. 5.

Fig. 7 shows a schematic current-voltage diagram of the emergency protection circuit in fig. 5 and 6.

Detailed Description

As can be seen from fig. 1 to 6, the shown embodiments of the sensor assembly 1, 1A, 1B, 1C, 1D for a vehicle according to the invention each comprise a sensor element WSS for detecting a measurement variable and at least two controllers ECU1, ECU1A, ECU1B, ECU1C, ECU1D, ECU2, ECU2A, ECU2B, ECU2C, ECU2D, the controllers each having a measurement circuit MS1, MS2 and a power supply VB1, VB 2. Here, the first terminal WSS of the sensor element WSS is connected to the power supply VB of the at least two controllers ECU, ECU1, ECU2, a first controller ECU of the ECU2, ECU1, and the second terminal WSS of the sensor element WSS is connected to the ground terminal GND via the measuring circuits MS, MS of the at least two controllers ECU, ECU1, ECU2, and the second controller ECU of the ECU2, ECU 2. The sensor current Is flowing through the sensor element WSS Is modulated with information about the measured variable detected, wherein the first measurement circuit MS1 of the first controller ECU1, ECU1A, ECU1B, ECU1C, ECU1D evaluates the sensor current Is detected in the high-side path between the power supply VB1 and the sensor element WSS, and the second measurement circuit MS2 of the second controller ECU2, ECU2A, ECU2B, ECU2C, ECU2D simultaneously evaluates the sensor current Is detected in the low-side path between the sensor element WSS and the ground terminal GND. Furthermore, the first emergency protection circuit 20A is arranged in parallel with the low-side path and monitors the voltage drop U12 at the second terminal WSS2 of the sensor element WSS. The first emergency protection circuit 20A provides an alternative low-side path for the sensor element WSS and receives the sensor current Is when the voltage drop U12 reaches the predetermined breakdown voltage value UK shown in fig. 7, so that at least the first measurement circuit MS1 can continue to evaluate the detected sensor current Is. Furthermore, the first emergency protection circuit 20A reduces the voltage drop U12 to a holding voltage value UH which is smaller than the breakdown voltage value UK as shown in fig. 7.

As can also be seen from fig. 1 to 4, in the embodiment shown, the two controllers ECU1, ECU1A, ECU1B, ECU1C, ECU1D, ECU2, ECU2A, ECU2B, ECU2C, ECU2D each comprise an evaluation and control unit 3A, 3B, implemented as an ASIC, integrated with a respective measuring circuit MS1, MS2, and an electric power source VB1, VB 2. Here, the first evaluation and control unit 3A is connected to the first power supply VB1 in the first controller ECU1, ECU1A, ECU1B, ECU1C, and ECU1D, respectively. The second evaluation and control unit 3B is connected to the second power supply VB2 in the second control units ECU2, ECU2A, ECU2B, ECU2C, and ECU2D, respectively.

In general, embodiments of the sensor arrangement 1, 1A, 1B, 1C, 1D for a vehicle according to the invention comprise a plurality of measuring points, each having such a sensor element WSS. For the sake of clarity, only one of the sensor elements WSS is shown in each of fig. 1, 2, 3 and 4. Thus, the embodiments of the sensor assemblies 1, 1A, 1B, 1C, 1D shown here are preferably used in vehicle brake systems. In such a brake system, the measuring points can, for example, each be assigned to a wheel, wherein the sensor element WSS can detect at least one revolution and/or rotational speed of the respective wheel. Thus, in a normal passenger vehicle having four wheels, the sensor assemblies 1, 1A, 1B, 1C, 1D have four such sensor elements WSS. Of course, other measurement variables, such as temperature, pressure, etc., can also be detected at such measurement points.

In the illustrated embodiment, the first emergency protection circuit 20A automatically disconnects the alternate low-side path again when the voltage drop U12 falls below the shutdown voltage value ABS, which is less than the hold voltage value UH, due to an external event. The mode of operation of the first emergency protection circuit 20A will now be described in detail with reference to fig. 5 to 7.

As can also be seen from fig. 1 and 2, in the illustrated exemplary embodiment of the sensor arrangement 1 according to the invention, a second emergency protection circuit 20B, illustrated in dashed lines, is optionally provided in each case, which is arranged parallel to the high-side path and monitors the voltage drop U12 at the first terminal WSS1 of the sensor element WSS. The second emergency protection circuit 20B provides an alternative high-side path for the sensor element WSS and receives the sensor current Is such that at least the second measurement circuit MS2 can continue to evaluate the detected sensor current Is when the voltage drop U12 reaches the predetermined breakdown voltage value UK, wherein the second emergency protection circuit 20B additionally reduces the voltage drop U12 to a holding voltage value UH which Is smaller than the breakdown voltage value UK. If the voltage drop U12 drops below the shutdown voltage value ABS, which is smaller than the holding voltage value UH, as a result of an external event, the second emergency protection circuit 20B automatically opens the alternative high-side path again.

The two emergency protection circuits are identical in structure and function and will be described in detail below with reference to fig. 5 to 7.

As can also be seen from fig. 5 and 6, the emergency protection circuits 20A, 20B comprise a voltage detector 22 and a current sink 24, respectively. Here, the voltage detector 22 drives the current sink 24 so as to establish a current path between the terminals a1, a2 of the respective emergency protection circuits 20A, 20B. The voltage detector 22 detects a voltage drop U12 between the first terminal a1 and the second terminal a2 of the respective emergency protection circuit 20A, 20B and drives the current sink 24 when the detected voltage drop U12 reaches a predetermined breakdown voltage value UK shown in fig. 7. The current sink 24 sets the voltage drop U12 to a predetermined hold voltage value UH and receives the sensor current Is. This characteristic is shown in fig. 7 as a solid line. When the voltage drop U12 rises, the voltage detector 22 in combination with the overvoltage protector U V drives the current sink 24 so that the sensor current Is drops to a minimum current or Is completely switched off. The protection curve SV is shown in fig. 7 by a dotted line. When the detected voltage drop U12 is below the predetermined off voltage value ABS, the voltage detector 22 terminates the driving of the current sink 24 and again interrupts the current path. This turn-off curve is shown in dashed lines in fig. 7.

As can also be seen from fig. 6, in the embodiment shown, the voltage detector 22 comprises a plurality of ohmic resistors R1, R2, R3, R4 and R5, two transistors T1, T2, which are implemented as bipolar transistors, and one zener diode ZD1, which are connected to each other as shown by respective lines, wherein the first transistor T1 is implemented as a PNP transistor and the second transistor T2 is implemented as an NPN transistor. In the illustrated embodiment, the current sink 24 comprises two ohmic resistors R6 and R7 and two transistors T3 and T4, implemented as bipolar transistors, which are connected to one another as shown by respective lines, wherein both transistors T3 and T4 are implemented as NPN transistors. In the embodiment shown, the overvoltage protector u V comprises an ohmic resistor R8.

As can also be seen from fig. 6, the resistors R1, R2, and R6 are the drain resistances of the bases of the transistors T1, T2, T3 to keep them turned off and divert the leakage current. If the current flowing through the zener diode ZD1 is greater than the current flowing through the second resistor R2, the second transistor T2 is turned on, which turns on the first transistor T1. This is the case in the illustrated embodiment when the applied voltage drop U12 exceeds a breakdown voltage value UK of about 3V. This breakdown voltage value corresponds to the sum of the breakdown voltage of the zener diode ZD1 (about 2.3V) and the base-emitter voltage of the second transistor T2 (about 0.7V). The first transistor T1 supplies current to the base of the second transistor T2 through the fourth resistor R4 so that it continues to remain on. The second transistor T2 and the first transistor T1 constitute a thyristor structure and are bridged over the zener diode ZD1 so that the voltage drop U12 is set to the holding voltage value UH of about 0.9V. The fourth transistor T4 of the current sink 24 Is driven via the fifth resistor R5 and the control line ST, wherein the sensor current Is, which now flows through the fourth transistor T4 in the exemplary embodiment shown, Is limited to approximately 40 mA. In case the driving current in the control line ST is very high, the third transistor T3 of the current sink 24 receives a part of the driving current of the fourth transistor T4 to protect it.

An overvoltage condition is illustrated in fig. 7 by the protection curve SV indicated by a dotted line and can be triggered, for example, by a short circuit to one of the supply voltages VB1, VB2, in which case the current sink 24 can no longer hold a low holding voltage value UH of the voltage drop U12 of approximately 0.9V if the current supplied to the current sink 24 is greater than the maximum load current of the current sink 24. Thus, the current through the eighth resistor R8 of the overvoltage protector u V increases. This causes the third transistor T3 to be turned on more and the driving of the fourth transistor T4 to be weakened. Thereby reducing the current into the base of the fourth transistor T4 and the fourth transistor T4 is further turned off and protected from damage (overload protection). In the case of a short circuit, the fourth transistor T4 may be switched to the off state.

If the voltage U12 drops to an off voltage value ABS of about 0.6V due to an external event, for example, due to a renewed switching on of the original low-side path in the second controller ECU2, the thyristor structure composed of the transistors T1 and T2 is switched off again. This turn-off curve is shown in dashed lines in fig. 7.

As can also be seen from fig. 1 to 4, in the embodiment shown, the sensor assemblies 1, 1A, 1B, 1C and 1D for the vehicle each comprise a current sensor 10 which detects a first measurement current IM1 in the high-side path and branches off a portion Is/n of the sensor current Is and supplies it to the first measurement circuit MS1 of the first controller ECU1, ECU1A, ECU1B, ECU1C, ECU 1D. Furthermore, the current sensor 10 conducts the sensor current Is to the first terminal WSS1 of the associated sensor element WSS. Here, in the illustrated embodiment, the second measurement circuit MS2 of the second controller ECU2, ECU2A, ECU2B, ECU2C, ECU2D receives the sensor current Is directly as the second measurement current IM2 and evaluates it. The sensor current Is flowing into the first terminal WSS1 of the sensor element WSS Is measured by means of the current sensor 10 and an equivalent but significantly smaller current Is/n Is fed to the first evaluation and control unit 3A to reduce power losses in the first controller ECU1, ECU1A, ECU1B, ECU1C, ECU 1D. In evaluating the first measurement current IM1, the first evaluation and control unit 3A takes into account the reduction of the second measurement current that is made. For this purpose, a corresponding adaptation of the input circuit or evaluation algorithm of the first measurement circuit MS1 can be carried out.

As can also be seen from fig. 1, in the illustrated first embodiment of the sensor assembly 1A for a vehicle, the first emergency protection circuit 20A and the optional second emergency protection circuit 20B are each implemented as separate components and are not integrated into one of the two controllers ECU1A, ECU 2A. However, in the illustrated first embodiment, the current sensor 10 that detects the sensor current Is in the high-side path and divides a part Is/n of the sensor current Is integrated in the first controller ECU 1A.

As can also be seen from fig. 2, in the illustrated second embodiment of the sensor assembly 1B for a vehicle, the first emergency protection circuit 20A is integrated into the first controller ECU 1A. In the illustrated second embodiment of the sensor assembly 1B for a vehicle, the optional second emergency protection circuit 20B is integrated into the second controller ECU 2B. Similar to the first embodiment, the current sensor 10 is integrated in the first controller ECU 1B.

As can also be seen from fig. 3 and 4, in the embodiment shown, the sensor assembly 1C, 1D for the vehicle comprises a switching device 30, respectively, which connects the first terminal WSS1 of the sensor element WSS with the first electrical power source VB1 of the first controller ECU1C, ECU1D and/or with the second electrical power source VB2 of the second controller ECU2C, ECU 2D. In case of a failure of the connected power supplies VB1, VB2, the switching device 30 automatically connects the first terminal WSS1 of the sensor element WSS with the other power supply VB2, VB 1. The switching device 30 preferably connects the first terminal WSS1 of the sensor element WSS with the first power supply VB1 of the first controller ECU1C, ECU 1D. If the first power supply VB1 fails, the switching device 30 connects the first terminal WSS1 of the sensor element WSS with the second power supply VB2 of the second controller ECU2C, ECU 2D.

As can also be seen from fig. 3 and 4, in the exemplary embodiment shown, the current sensor 10 and the switching device 30 are combined in an interconnection module 40, which may be embodied, for example, as an ASIC module.

As can also be seen from fig. 3, in the illustrated third embodiment of the sensor assembly 1C for a vehicle, the first emergency protection circuit 20A is implemented as a separate component and is not integrated into one of the two controllers ECU1C, ECU 2C. The interconnect module 40 is likewise implemented as a separate component and is not integrated into one of the controllers ECU1C, ECU 2C. However, in an alternative embodiment not shown, the first emergency protection circuit 20A may be integrated into the first controller ECU1C similar to the second embodiment of the sensor assembly 1B.

As can also be seen from fig. 4, in the illustrated fourth embodiment of the sensor assembly 1D for a vehicle, the first emergency protection circuit 20A is integrated into the first controller ECU 1D. The interconnection module 40 is also integrated into the first controller ECU 1D. However, in an alternative embodiment not shown, the first emergency protection circuit 20A may be implemented as a separate component and not integrated into the first controller ECU1C, similar to the first and third embodiments of the sensor assembly 1B.