SENSOR MODULE

Description

[0001] The invention relates to a sensor module with at least two sensor units, a control unit configured to set an electrical supply voltage for the sensor units, and with at least one sensor signal output, wherein the at least two sensor units are electrically connectable to or disconnectable from the control unit and electrically connected to the sensor signal output, wherein a first of the sensor units provides a first output signal through the sensor signal output in normal operation of the sensor module and a second of the sensor units provides a second output signal through the sensor signal output in energy-saving operation of the sensor module, and wherein a decision unit is assigned to the control unit, which is configured to electrically connect either the first sensor unit or the second sensor unit to the control unit.

[0002] The invention further relates to a braking system with such a sensor module.

[0003] Furthermore, the invention relates to a method for operating the sensor module. State of the art

[0004] Sensor modules of the type mentioned above are known in principle from the prior art. For example, German patent DE 10 2012 017 780 B4 discloses a sensor module designed as a microcontroller unit for motor vehicles, which has at least two sensor units in the form of microcontrollers assigned to the sensors of the motor vehicle or designed to operate these sensors. A first of the sensor units is designed as a main sensor unit active in normal operation, which processes various input variables sensed by the sensors and generates at least one output signal based on the processing. A second of the sensor units is designed as a standby microcontroller active in energy-saving mode, which generates at least one second output signal. The first and the second output signals are provided via a sensor signal output of the sensor module that is shared by both sensor units.

[0005] The sensor module is associated with a voltage source, which is connected to a control unit of the sensor module designed as a current control device. This allows the supply voltage provided by the voltage source to be made available for operating the sensor module via the control unit. The control unit is configured to electrically connect or disconnect the sensor units from the voltage source, with typically only one of the sensor units operating at any given time. The control unit also functions as a decision point, responsible for electrically connecting either the first or the second sensor unit to the voltage source.

[0006] Disclosure DE10 054 745 A1 deals with a method for the secure transmission of sensor signals via signal lines to an electronic processing unit for a motor vehicle braking system.

[0007] Disclosure DE 10 2009 008 483 A1 relates to a device for measuring a physical quantity in a motor vehicle.

[0008] Disclosure DE 10 2019 202 011 A1 relates to a sensor arrangement for a vehicle braking system, with a braking system connection interface.

[0009] Document EP 3 531 081 A1 concerns sensor devices, methods and sensor systems for determining the position of actuated objects, in particular devices, methods and systems for determining the position of moving vehicle parts using magnetic field sensors exposed to rotating magnetic fields. Disclosure of the invention

[0010] The sensor module with the features of claim 1 has the advantage of a simplified technical design. According to the invention, the decision unit is configured to electrically connect or disconnect the first or second sensor unit from the control unit depending on the set electrical supply voltage, and the control unit is configured to change the supply voltage, at least in energy-saving mode, when the output signal provided by the sensor signal output reaches a defined threshold. In particular, the control unit is configured to change the supply voltage when the output signal exceeds or falls below the threshold.The selection of which of the two sensor units is operated depends on the set electrical supply voltage, so that the sensor module is designed to be implemented in a technically relatively simple way.

[0011] Adjusting its supply voltage controls the activity of the sensor units. Therefore, no additional communication interface or signal is required to activate or deactivate the sensor units, making the sensor module, particularly the decision unit and the sensor units, comparatively easy to design, especially from a communication technology perspective. Furthermore, the variable supply voltage provided for in the invention ensures particularly energy-efficient operation of the sensor module.

[0012] According to a preferred embodiment, the control unit is provided with at least one circuit unit for detecting the output signal provided by the sensor signal output. This allows the control unit itself to detect and process the output signal, eliminating the need for an additional, and particularly complex, evaluation unit. This further simplifies the design of the sensor module. Specifically, the circuit unit includes a pull-up resistor.

[0013] In particular, the decision unit includes a Zener diode, a comparator, or a circuit with an operational amplifier. This allows for a particularly simple design of the decision unit.

[0014] Preferably, each sensor unit is assigned a switch, in particular a transistor, which can be controlled by the decision unit and by means of which the respective sensor unit can be electrically connected to or disconnected from the control unit to supply the sensor unit with the supply voltage. Advantageously, this makes the electrical connection or disconnection of the sensor units from the control unit particularly easy to implement.

[0015] Preferably, each sensor unit has an open collector or open drain output by means of which the respective sensor unit is electrically connected to the sensor signal output. This has the advantage that a signal line assigned to the inactive sensor unit, and in particular the sensor signal output shared by the sensor units, is not burdened by the inactive sensor unit. Both sensor units are preferably connected to the sensor signal output, so that no additional switch, in particular a multiplexer, is required. Alternatively, at least one of the sensor units has another switchable output, in particular a tri-state output.

[0016] According to a preferred further development, the second sensor unit is designed as a standby sensor, in particular a Hall effect switch. This further simplifies the design of the sensor module.

[0017] The braking system with the features of claim 7 is characterized in that the sensor module is designed according to the invention as described above. The advantages already mentioned in this regard result.

[0018] The method for operating a sensor module with the features of claim 8 is characterized in that, depending on the set electrical supply voltage, either the first sensor unit or the second sensor unit is electrically connected to or disconnected from the control unit, and that the supply voltage is changed, at least in energy-saving mode, when the output signal provided by the sensor signal output reaches a defined threshold value. In particular, the supply voltage is changed when the output signal exceeds or falls below the threshold value. Preferably, the output signal provided by the sensor signal output is detected by a circuit unit of the control unit in order to change the supply voltage.In particular, the respective sensor unit is electrically connected to or disconnected from the control unit by means of a switch, especially a transistor, assigned to the sensor unit and controllable by the decision unit. This results in the advantages already mentioned above.

[0019] The method for operating a braking system, in particular the braking system described above, with the features of claim 11, is characterized in that the sensor module is operated according to the method for operating a sensor module described above. The advantages already mentioned in this regard result.

[0020] Preferred features and combinations of features are particularly evident from the foregoing and the claims. The invention will now be explained in more detail with reference to the figures. These figures show: Figure 1 is a highly simplified schematic representation of an advantageous braking system with an advantageous sensor module, and Figure 2 is a schematic flow diagram of an advantageous method for operating the braking system or the sensor module.

[0021] Figure 1 Figure 1 shows an advantageous braking system 1 for a motor vehicle not shown here in a highly simplified schematic representation. The braking system 1 has a Figure 1 The figure shows an electromechanical brake booster 2 (shown only as an example), an actuator 3 (shown here symbolically and designed as the vehicle's brake pedal), and a sensor module 4. The sensor module 4 serves to control the brake booster 2 based on a movement of the actuator 3 by a vehicle user, in order to generate a braking force to decelerate the vehicle. For this purpose, the sensor module 4 is connected to the actuator 3 as shown in Figure 1 exemplified by a dashed arrow 5, assigned and designed to control the brake booster 2 depending on a displacement of the actuating element 3.

[0022] According to the present embodiment, the sensor module 4 has two sensor units 6, 7, which in this instance serve to sense the displacement of the actuating element 3. The sensor module 4 also has a control unit 8, which is configured to supply an electrical voltage, which in this embodiment is supplied by a Figure 1The voltage source (not shown) is provided for the sensor units 6, 7. To supply the sensor units 6, 7 with the supply voltage, they are electrically connected to or disconnected from the control unit 8 using a supply terminal 9 and two switches 10, 11, each assigned to one of the sensor units 6, 7. The sensor module 4 also has a sensor signal output 12 shared by the sensor units 6, 7, to which the two sensor units 6, 7 are always electrically connected. The sensor signal output 12, in turn, is electrically connected to the control unit 8 to provide the control unit 8 with output signals 13, 14 generated by the sensor units 6, 7 for further processing, as will be explained in more detail later.

[0023] In the present embodiment, a first sensor unit 6 is configured as an operating sensor that is active during normal operation of the sensor module 4 and provides a first output signal 13 via the sensor signal output 12. In the present embodiment, a second sensor unit 7 is configured as a standby sensor, in particular a Hall effect switch, which provides a second output signal 14, different from the first output signal 13, via the sensor signal output 12 during energy-saving operation of the sensor module 4 in which the first sensor unit 6 is inactive. Therefore, the sensor signal output 12 advantageously serves to provide both the first output signal 13 and the second output signal 14.To prevent interference and thus impairment of the output signals 13, 14, it is necessary that only one of the sensor units 6, 7 is in operation at any given time, or at least generates the respective output signal. Therefore, one of the switches 10, 11 is always closed, while the other switch 11, 10 is open, so that only one of the sensor units is supplied with voltage and thus active at any given time. To ensure or control this, the sensor module 4 also includes a decision unit 15, which comprises, in particular, a Zener diode, a comparator, or a circuit with an operational amplifier, and is configured to electrically connect or disconnect either the first sensor unit 6 or the second sensor unit 7 from the control unit 8 by controlling the switches 10, 11.

[0024] Advantageously, the selection of which of the two sensor units 6, 7 is to be electrically connected to the control unit 8 and thus operated is controlled by an adjustment of the supply voltage by the control unit 8. For this purpose, the decision unit 15 is configured to electrically connect either the first sensor unit 6 or the second sensor unit 7 to the control unit 8, depending on the set electrical supply voltage. In this respect, the decision unit 15 is configured to detect a change in the supply voltage and, based on this, to decide which of the two sensor units 6, 7 is to be electrically connected to the control unit 8 and thus operated.The control unit 8 adjusts or changes the supply voltage accordingly, depending on the output signal 13, 14 provided by the signal output 12, particularly when the output signal 13, 14 currently provided by the sensor signal output 12 reaches a defined threshold value. To detect and evaluate the corresponding output signal 13, 14, the control unit 8 has at least one circuit unit 16, in particular with a pull-up resistor. This enables the control unit 8 to detect when the defined threshold value is reached and to adjust the supply voltage accordingly.

[0025] As mentioned above, the sensor signal output 12 is used to provide both the first output signal 13 and the second output signal 14. To avoid unnecessarily burdening the corresponding signal lines associated with the sensor signal output 12, the sensor units 6 and 7 each have an open-drain or open-collector output 17, by means of which the sensor units 6 and 7 are connected to the sensor signal output 12. The supply voltage is then changed when a voltage level of the open-drain or open-collector output 17, as output signal 13 or 14, falls below the threshold value.

[0026] According to the present embodiment, the control unit 8, the sensor units 6, 7, and the decision unit 15 are designed discretely, i.e., as separate elements, and are connected to each other by means of cables or wires. Optionally, however, at least the decision unit 15 and the sensor units 6, 7 can be arranged on a common circuit board 18, as shown in Figure 1 This is illustrated by dashed lines. In particular, the sensor units 6, 7 and the decision unit 15 are mounted on a common semiconductor chip.

[0027] The following will now be based on the in Figure 2 The schematic flowchart shown illustrates an advantageous method for operating the brake system 1 or its sensor module 4.

[0028] The process begins in a first step S1, in which the brake system 1 or the sensor module 4 is in energy-saving mode. Therefore, at this point, the second sensor unit 7 is active and the first sensor unit 6 is inactive, and the second switch 11 is closed and the first switch 10 is open, as shown in Figure 1As shown in the figure. Accordingly, in step S1, the second sensor unit 7 is electrically connected to the control unit 8 and is operated by means of the supply voltage. In a second step S2, the actuator 3 is actuated by the vehicle user. This is detected by the second sensor unit 7, and the second output signal 14 is then provided to the control unit 8 via the sensor signal output 12. In a subsequent step S3, the circuit unit 16 detects that the second output signal 14 has reached the defined threshold value, whereupon the control unit 8 changes the supply voltage, preferably increasing it. As a result, a modified, in particular increased, supply voltage is provided via the supply terminal 9.In the next step S4, the change in the supply voltage is detected by the decision unit 15, and the second switch 11 is opened and the first switch 10 is closed to deactivate the second sensor unit 7 and activate the first sensor unit 6. In a further step S5, the first sensor unit 6 then senses the further or continuous displacement of the actuator 3 and consequently provides the first output signal 13 to the control unit 8 via the sensor signal output 12. The first output signal 13 has a protocol for operating the brake booster 2 and is evaluated by the control unit 8 in a further step S6.Based on this evaluation, in the next step S7, the control unit 8 or the sensor module 4 activates the brake booster 2 to realize the braking force requested by the user through the actuation of the actuator 3. If, in a further step S8, a request to switch the brake system 1 back to energy-saving mode is detected, for example, when the user has switched off or left the vehicle, the first output signal 13 is modified so that it reaches a defined threshold value, thus indicating to the control unit 8 that the supply voltage should be changed again.In a final step S9, the supply voltage from the control unit 8 is then changed again, in particular reduced, so that the decision unit 15 deactivates the first sensor unit 6 and reactivates the second sensor unit 7 by appropriately controlling the two switches 10 and 11. The procedure then starts again with step S1.

Claims

1. Sensor module (4) having at least two sensor units (6, 7), a control device (8) which is designed to set an electrical supply voltage for the sensor units (6, 7), and having at least one sensor signal output (12), wherein the at least two sensor units (6, 7) are able to be electrically connected to or electrically disconnected from the control device (8) and are electrically connected to the sensor signal output (12), wherein a first of the sensor units (6) in a normal mode of the sensor module (4) provides a first output signal (13) through the sensor signal output (12) and a second of the sensor units (7) in an energy-saving mode of the sensor module (4) provides a second output signal (14) through the sensor signal output (12), and wherein the control device (8) is assigned a decision-making unit (15) which is designed to electrically connect either the first sensor unit (6) or the second sensor unit (7) to the control device (8), wherein the decision-making unit (15) is designed to electrically connect or electrically disconnect the first sensor unit (6) or the second sensor unit (7) to / from the control device (8) in dependence on the set electrical supply voltage, and in that the control device (8) is designed to change the supply voltage at least in the energy-saving mode if the output signal (13, 14) provided by the sensor signal output (12) reaches a defined threshold value.

2. Sensor module according to Claim 1, characterized in that the control device (8) has at least one switching unit (16), in particular having a pull-up resistor, for detecting the output signal (13, 14) provided by the sensor signal output (12).

3. Sensor module according to either of the preceding claims, characterized in that the decision-making unit (15) has a Zener diode, a comparator or a circuit having an operational amplifier.

4. Sensor module according to one of the preceding claims, characterized in that each of the sensor units (6, 7) is assigned a switch (10, 11), in particular in the form of a transistor, which is able to be controlled by the decision-making unit (15) and by means of which the respective sensor unit (6, 7) is able to be electrically connected to the control device (8), for the purpose of supplying the sensor unit (6, 7) with the supply voltage, or is able to be electrically disconnected therefrom.

5. Sensor module according to one of the preceding claims, characterized in that the sensor units (6, 7) each have an open-collector output, an open-drain output (17), or an output which is able to be switched off in another way, in particular a tri-state output, by means of which the respective sensor unit (6, 7) is electrically connected to the sensor signal output (12).

6. Sensor module according to one of the preceding claims, characterized in that the second sensor unit (7) is in the form of a standby sensor, in particular a Hall-effect switch.

7. Brake system (1) having a brake booster (2), in particular an electromechanical or electrohydraulic brake booster, an actuation element (3) which is able to be moved by a user, in particular a brake pedal, and having a sensor module (4) which is assigned to the actuation element (3) and is designed to control the brake booster (2) in dependence on a movement of the actuation element (3), characterized by a design of the sensor module (4) according to one of Claims 1 to 6.

8. Method for operating a sensor module which has at least two sensor units (6, 7), a control device (8) which is designed to set an electrical supply voltage for the sensor units (6, 7), and at least one sensor signal output (12), wherein the at least two sensor units (6, 7) are able to be electrically connected to or electrically disconnected from the control device (8) and are electrically connected to the sensor signal output (12), wherein a first of the sensor units (6) in a normal mode of the sensor module (4) provides a first output signal (13) through the sensor signal output (12) and a second of the sensor units (7) in an energy-saving mode of the sensor module (4) provides a second output signal (14), which differs from the first output signal (13), through the sensor signal output (12), and wherein the control device (8) is assigned a decision-making unit (15) which is designed to electrically connect either the first sensor unit (6) or the second sensor unit (7) to the control device (8), wherein either the first sensor unit (6) or the second sensor unit (7) is electrically connected to or electrically disconnected from the control device (8) in dependence on the set electrical supply voltage, and in that the supply voltage at least in the energy-saving mode is changed if the output signal (13, 14) provided by the sensor signal output (12) reaches a defined threshold value.

9. Method according to Claim 8, characterized in that the output signal (13, 14) provided by the sensor signal output (12) is detected by a switching unit (16) of the control device (8) in order to change the supply voltage.

10. Method according to Claim 8 or 9, characterized in that the respective sensor unit (6, 7) is electrically connected to the control device (8), for the purpose of supplying the sensor unit (6, 7) with the supply voltage, or is electrically disconnected therefrom by means of a switch (10, 11), in particular a transistor, which is assigned to the sensor unit (6, 7) and is able to be controlled by the decision-making unit (15).

11. Method for operating a brake system (1), in particular a brake system according to Claim 7, which has a brake booster (2), in particular an electromechanical or electrohydraulic brake booster, an actuation element (3) which is able to be moved by a user, in particular a brake pedal, and a sensor module (4) which is assigned to the actuation element (3), wherein the brake booster (2) is controlled by the sensor module (4) in dependence on a movement of the actuation element (3), characterized in that the sensor module (4) is operated according to the method according to one of Claims 8 to 10.