Device for supplying power to a control unit and method for monitoring a power supply

Abstract

Device (104) for supplying power to a control unit (102) for a vehicle (100), wherein the device (104) has the following features: a first terminal (110) for a first power supply path, a second terminal (112) for a second power supply path and a star point (114) for connecting the first power supply path and the second power supply path, wherein the star point (114) represents a ground terminal for an electrical circuit of the control unit (102), the first power supply path and the second power supply path, wherein the two power supply paths at the two terminals (110, 112) represent redundant ground power supply paths and the terminals (110, 112) are designed as interfaces for electrically contacting the control unit (102); a first switch (116) with a first contact (244) and a second contact, wherein the first contact (244) is connected to the first terminal (110) and the second contact is connected to the star point (114), and a second switch (118) with a first contact (246) and a second contact, wherein the first contact (246) is connected to the second terminal (112) and the second contact is connected to the star point (114); a diode (240) connected in parallel to the first switch (116) between the first terminal (110) and the star point (114), and another diode (242) connected in parallel to the second switch (118) between the second terminal (112) and the star point (114), the anodes of the diodes (240, 242) being connected to the star point 114; a first measuring contact (120) for detecting a first measured value (264) representing a voltage potential of the first power supply path, and a second measuring contact (122) for detecting a second measured value (266) representing a voltage potential of the second power supply path; a control device (124) configured to keep one of the switches (116, 118) open and the other of the switches (116, 118) closed in response to a test state of the device (104); and a monitoring device (126) configured to provide a monitoring signal (130) using the first measured value (264) and the second measured value (266) when the device (104) is in the test state.

Description

[0001] The invention relates to a device for supplying power to a control unit, a control unit and a method for monitoring a power supply.

[0002] Vehicles contain electronic control units (ECUs) that control, for example, safety-relevant functions. These ECUs require a reliable power supply.

[0003] US patents 2014 / 0 159 908 A1 and 2014 / 0 084 933 A1 each disclose a device for monitoring the insulation of a battery. DE 10 2010 033 440 A1 discloses a method for the safety shutdown of an electromechanical power steering system in a motor vehicle.

[0004] US patent 2012 / 0161822 A1 discloses a device for driving an electrical load.

[0005] DE 10 2006 040 753 A1 discloses a redundant power supply with diagnostic capability and protective circuitry. The circuit arrangement comprises a first current path with a first switching element, a second current path with a second switching element, and a common output terminal of the first and second current paths. In a normal operating state, the switching elements are in a forward state, and in an abnormal operating state, the switching element of the current path with the poorer electrical characteristics switches to a reverse state.

[0006] US Patent 2013 / 0278272 A1 deals with a device for monitoring a high voltage potential at a voltage converter in a vehicle. For voltage conversion, the high and low voltage potentials can be switched via switches to an intermediate line. A resistance between the high and low voltage potentials can be measured to detect a fault.

[0007] US Patent 8,829,718 B2 describes a DC-DC converter connected to a low-voltage battery via an ignition switch and started by the ignition switch. A transformer unit converts a voltage input from a high-voltage battery and supplies this voltage to the low-voltage battery. A control circuit calculates the wiring resistance between the transformer unit and the low-voltage battery based on the voltage input from the low-voltage battery via the ignition switch when the ignition switch is connected, and an output voltage and current from the transformer unit.

[0008] The invention aims to provide an improved power supply device for a control unit, an improved control unit and an improved method for monitoring a power supply.

[0009] According to the invention, this problem is solved by a device for supplying power to a control unit, a control unit, and a method for monitoring a power supply with the features of the main claims. Advantageous embodiments and further developments of the invention are described in the following dependent claims.

[0010] A power supply device for a vehicle control unit has the following features: a first terminal for a first power supply path, a second terminal for a second power supply path and a star point for connecting the first power supply path and the second power supply path; a first switch with a first contact and a second contact, wherein the first contact is connected to the first terminal and the second contact is connected to the star point; and a second switch with a first contact and a second contact, wherein the first contact is connected to the second terminal and the second contact is connected to the star point; a first measuring contact to detect the voltage potential of the first power supply path representing the first measured value, and a second measuring contact to detect the voltage potential of the second power supply path representing the second measured value; a control device configured to keep one of the switches open and the other switch closed in response to a test state of the device; and a monitoring device designed to provide a monitoring signal using the first and second measured values ​​when the device is in the test state.

[0011] The vehicle can be, for example, a vehicle for passenger transport or for the transport of goods. For instance, the vehicle could be a motor vehicle, an electric vehicle, or a rail vehicle. The control unit can be an electrical device that, for example, can read sensor signals via an interface and use these sensor signals to output control signals for a function of the vehicle via an interface. The two power supply paths can be redundant. Thus, a supply voltage required for the operation of the control unit can be present at both the first and the second connection, or a supply current required for the operation of the control unit can flow through both the first and the second connection.A switch can allow current flow between its contacts in a closed state and prevent it in an open state. A measured value can be a voltage value. This voltage value can correspond to, or be dependent on, the voltage potential of the corresponding power supply path. In the test state of the device, the power supply paths, or at least one of them, can be checked, for example, for the presence of a fault caused by a short circuit. The control device can be configured to actuate the switches by providing at least one control signal to an interface with the switches. The monitoring device can be configured to evaluate the measured values ​​in order to detect the presence of a fault in at least one of the power supply paths.The measured values ​​can be combined. The monitoring signal can be configured to indicate a fault-free state or a fault in at least one of the power supply paths. The test state can be assumed by the device, for example, before commissioning or briefly during operation.

[0012] The device can include a diode (e.g., the body diode of a FET) connected in parallel to the first switch between the first terminal and the neutral point. Similarly, the device can include another diode (e.g., the body diode of a FET) connected in parallel to the second switch between the second terminal and the neutral point. The diodes allow current to flow between the neutral point and the respective terminal even when the respective switch is open. The diode can be implemented as a discrete component or as part of a circuit assembly comprising the diode and the respective switch.

[0013] The control device can be configured to close the switches promptly when the device is put into operation. This minimizes the resistance between the neutral point and the terminals. When the device is taken out of service, the control device can be configured to open the switches.

[0014] The control device can be configured to keep the first switch open and the second switch closed during the first phase of the test state. During the second phase of the test state, the control device can be configured to keep the first switch closed and the second switch open. The first and second phases can occur consecutively or be spaced apart in any order. By alternately opening the first and second switches while the other switch is closed, the power supply paths can be tested alternately.

[0015] The star point can represent a ground connection for an electrical circuit of the control unit. Therefore, the power supply paths can be ground power supply paths, so-called GND power supply paths, or simply GND paths. Alternatively, the star point can be assigned to a different voltage potential.

[0016] The monitoring device can be configured to compare the first and second measured values ​​to detect any deviation between the voltage potentials of the power supply paths. The monitoring signal can then indicate this deviation. By comparing the readings, it can be easily determined if one of the power supply paths is not operating at the intended voltage potential.

[0017] According to one embodiment, the first measuring contact can be arranged on a first connecting line between the first terminal and the first contact of the first switch. Similarly, the second measuring contact can be arranged on a second connecting line between the second terminal and the first contact of the second switch. This allows for a very simple implementation.

[0018] The device may have a third terminal for providing a voltage potential. Furthermore, the device may have a first stub line comprising at least one resistor and one diode, connecting the third terminal to the first terminal, and a second stub line comprising at least one resistor and one diode, connecting the third terminal to the second terminal. In this case, the first measuring contact may be located on the first stub line and the second measuring contact on the second stub line, or coupled to the respective stub line. The resistors enable the detection of a voltage difference between the first and third terminals, as well as between the second and third terminals. If the power supply paths are undisturbed, the voltage differences should be equal, provided the resistances and currents in the individual paths are equal.

[0019] A vehicle control unit may include a power supply device. This device may be integrated into the control unit, for example, located within a housing that encloses the control unit. Advantageously, the device can detect and indicate any fault in the control unit's power supply.

[0020] A method for monitoring a power supply for a control unit for a vehicle, wherein the power supply is connected using a first terminal for a first power supply path, a second terminal for a second power supply path, and a star point for connecting the first and second power supply paths, as well as a first switch having a first contact and a second contact, wherein the first contact is connected to the first terminal and the second contact is connected to the star point, and a second switch having a first contact and a second contact, wherein the first contact is connected to the second terminal and the second contact is connected to the star point, as well as a first measuring contact for detecting a first measured value representing a voltage potential of the first power supply path.and a second measuring contact for capturing a second measured value representing a voltage potential of the second power supply path, comprises the following steps: Providing at least one control signal to an interface with the switches to keep one of the switches open and the other of the switches closed; and Reading the first and second measured values; and Providing a monitoring signal using the measured values.

[0021] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows: Fig. 1 a schematic representation of a vehicle with a control unit with a power supply device according to an exemplary embodiment; Fig. 2 a circuit diagram of a control unit with a power supply device according to an exemplary embodiment; Fig. 3 a circuit diagram of a power supply device according to an exemplary embodiment; Fig. 4 a circuit diagram of a power supply device according to an exemplary embodiment; and Fig. 5 a flowchart of a method for supplying power according to an exemplary embodiment.

[0022] In the following description of favorable embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and acting similarly, without repeating these elements.

[0023] Fig. Figure 1 shows a schematic representation of a vehicle 100 with a control unit 102 and a power supply device 104 according to an exemplary embodiment. For example, the control unit 102 can be used to provide a function required for a driver assistance function or for a function required for the operation of the vehicle 100.

[0024] The device 104 comprises a first terminal 110 for a first power supply path, a second terminal 112 for a second power supply path, and a star point 114 for connecting the first and second power supply paths. According to this embodiment, terminals 110 and 112 are configured as interfaces for electrically contacting the control unit 102. The star point 114 is located inside the control unit 102.

[0025] The device 104 further comprises a first switch 116, which is connected between the first terminal 110 and the star point 114, and a second switch 118, which is connected between the second terminal 112 and the star point 114.

[0026] A first measuring contact 120 is arranged here by way of example on a line connecting the first terminal 110 with the first switch 116 and a second measuring contact 122 is arranged by way of example on a line connecting the second terminal 112 with the second switch 118.

[0027] The device 104 further comprises a control unit 124 and a monitoring unit 126. The control units 124 and the monitoring unit 126 can be designed as separate units, combined in one unit, or, for example, integrated into a circuit 128 to provide the function of the control unit 102.

[0028] The device 104 can enter a test state in which the power supply paths are checked. Responding to or during the test state, the control device 124 is configured to keep one of the switches 116, 118 open and the other of the switches 116, 118 closed.

[0029] The monitoring device 126 is configured to read a first measured value via the first measuring contact 120 and a second measured value via the second measuring contact 122, and to provide a monitoring signal 130 using the first and second measured values. According to one embodiment, the monitoring signal 130 indicates that a fault exists on one of the power supply paths when a deviation between the measured values ​​is detected. According to one embodiment, the monitoring signal 130 is provided to a warning device 132 of the vehicle 100.

[0030] According to one embodiment, the voltage potential applied to the star point 114 is used to operate the circuit 128.

[0031] Fig. Figure 2 shows a circuit diagram of a control unit 102 with a power supply device 104 according to an exemplary embodiment. This can be an exemplary embodiment of the one described above. Fig. 1 described control unit 102.

[0032] In addition to the points already mentioned, Fig. According to this embodiment, the device 104, as described in section 1, comprises a diode 240 connected in parallel to the first switch 116 and a further diode 242 connected in parallel to the second switch 118. The anodes of diodes 240 and 242 are connected to the star point 114 in this embodiment.

[0033] The first measuring contact 120 is arranged on a line 250 connecting the first terminal 110 to a first contact 244 of the first switch 116, and the second measuring contact 122 is arranged on a line 252 connecting the second terminal 112 to a first contact 246 of the second switch 118. According to this embodiment, the lines 250 and 252 are connected via a series circuit of two resistors 254 and 256. A third terminal 258 is connected to a line connecting the resistors 254 and 256.

[0034] According to one embodiment, a voltage potential GND 1 is present at the first terminal 110, a voltage potential GND 2 at the second terminal 112, and a voltage potential VDD at the third terminal 258. During normal operation of the control unit 102, the voltage potentials GND 1 and GND 2 are equal and differ from the voltage potential VDD. Therefore, resistors 254 and 256 act as pull-up and pull-down resistors, respectively.

[0035] The control unit 124 and the monitoring unit 126 are combined in a microcontroller according to this embodiment.

[0036] The control device 124 is configured to provide a first control signal 260 to a control input of the first switch 116 and a second control signal 262 to a control input of the second switch 118. In the illustrated state of the device 104, the control signals 260 and 262 are suitable, for example, due to their current signal level, to hold the switches 116 and 118 in an open position.

[0037] The monitoring device 126 is designed to read a first measured value 264 via the first measuring contact 120 and a second measured value 266 via the second measuring contact 122. The first measured value 264 represents a voltage potential applied to the first line 250, and the second measured value 266 represents a voltage potential applied to the second line 252.

[0038] According to this embodiment, the star point 114 is connected to a resistor 268, which is also referred to as resistor RL.

[0039] According to one embodiment, the approach described here is used for reverse polarity protection for a redundant power supply in safety-critical systems.

[0040] In automotive engineering, particularly for safety-critical systems such as ABS / EBS / ESP / transmission actuators, increasing emphasis is placed on a stable and reliable power supply to ensure the continuous availability of these systems. For this reason, these systems require a redundant power supply. The devices, such as the control unit 102 shown, each have two completely separate and independently routed supply lines for the battery voltage (UB) and ground (GND), which are connected to the control unit 102, also known as the ECU, via terminals 110 and 112. There, these two redundant lines can be joined together at the star point 114, for example, to form a common power supply.

[0041] To ensure the functionality of the redundant power supply, special monitoring of the individual supply lines is necessary. Faults in the supply lines, connectors, fuses, etc., should be reliably detected and indicated, for example, via the monitoring signal 130. In the event of a fault, one power supply path can then be switched off to prevent a continuous current flow through the control unit 102. In this case, the power supply remains fully functional via the remaining intact power supply path. Thus, a quasi-redundant system with two separate supply lines, which are combined in the control unit 102, can be implemented.

[0042] For this purpose, two redundant power supply paths, in this case GND power supply paths, are provided, the condition of which can be diagnosed. In the event of a fault where one power supply path is defective, the power supply for the entire device 102 is possible via the other, still intact power supply path.

[0043] According to the described approach, there are essentially two independent power supply paths. During fully functional normal operation, both power supply paths are connected in parallel, so that the total power consumption of the system is ideally distributed evenly between these two power supply paths.

[0044] The quality of each power supply path can be determined by cyclical, alternating test pulses on both paths. In case of a fault, the vehicle driver can be warned, for example, using warning device 132, and the system can be brought to a safe shutdown state. The two redundant power supply paths feature switchable diodes 240 and 242 and positive / negative voltage measurement using the readings 264 and 266.

[0045] The described approach offers numerous advantages according to various embodiments. For example, one embodiment provides two independent power supply paths (redundancy) for the negative (GND) branch. Testable and switchable reverse polarity protection diodes are used. Detection of an interruption in a GND power supply path is possible. Furthermore, detection of a short circuit to the battery voltage and shutdown of this power supply path is possible to prevent the continuous flow of high currents through the control unit 102. Detection of a short circuit between the internal and external ground potentials (GND) is also possible. Finally, the need for otherwise required reverse polarity protection diodes on circuit breakers is eliminated.The control unit 102 remains diagnosable due to the disconnection of the defective GND input (in the form of one of the connections 110 or 112) from the internal ground potential, which is connected to the star point 114. This allows the control unit to communicate the fault condition to other systems in the vehicle, thus ensuring functional safety.

[0046] Fig. Figure 3 shows a circuit diagram of a power supply device 104 according to an exemplary embodiment. This can be an exemplary embodiment based on Fig. 2 described device.

[0047] According to this embodiment, the first switch 116 and the diode 240 are implemented by a first transistor arrangement, and the second switch 118 and the further diode 242 are implemented by a second transistor arrangement.

[0048] To control the switches 116, 118, the device 104 according to this embodiment comprises a fourth terminal 370, a first transistor 371, a second transistor 372, a third transistor 373, a fourth transistor 374, a third resistor 375, a fourth resistor 376, a fifth resistor 377 and a sixth resistor 378. During operation of the device 104, a voltage potential VDD10 is applied to the fourth terminal 370, which differs, for example, from the voltage potential applied to the third terminal 258, here for example VDD5.

[0049] The first control signal 260 is provided to a control input of the first transistor 371, which is connected between a control input of the second transistor 372 and a ground terminal. The second transistor 372 is connected between the fourth terminal and a first contact of the third resistor 375. A second contact of the third resistor 375 is connected to a control terminal of the first switch 116 and a first contact of the fourth resistor 376. A second contact of the fourth resistor 376 is connected to the star point 114.

[0050] The second control signal 262 is supplied to a control input of the third transistor 373, which is connected between a control input of the fourth transistor 374 and the ground terminal. The third transistor 373 is connected between the fourth terminal and the first contact of the fifth resistor 377. The second contact of the fifth resistor 377 is connected to a control terminal of the second switch 118 and the first contact of the sixth resistor 378. The second contact of the sixth resistor 378 is connected to the star point 114.

[0051] According to this embodiment, the third terminal 258 is connected to the first line 250 via the first resistor 254 and a first diode 380. Similarly, according to this embodiment, the third terminal 258 is connected to the second line 252 via the second resistor 256 and a second diode 382.

[0052] According to this embodiment, the first measured value 264 is read from the first measuring point 120 via a seventh resistor 382, ​​which is located on a connecting line linking the first resistor 254 and the first diode 380. The second measured value 266 is read from the second measuring point 122 via an eighth resistor 383, which is located on a connecting line linking the second resistor 256 and the second diode 382.

[0053] According to one embodiment, in the inactive state of the circuit implementing device 104, the two switches 116, 118, also referred to as main switches or GND switches, are not switched on. The two switches 116, 118 remain conductive even when switched off due to their integrated diodes 240, 242, which are implemented here as body diodes, preferably using MOSFETs for the switches 116, 118.

[0054] The internal ground potential 384, also known as internal GND, which is connected to star point 114, is always switched on when the polarity is correct, regardless of whether switches 116 and 118 are actually activated or not.

[0055] Once the power supply is switched on with correct polarity, the two switches 116 and 118 are closed after verifying the potentials GND1 and GND2 at terminals 110 and 112. This ensures that there is only a negligible potential difference between the internal ground potential 384 at star point 114 and the two terminals 110 and 112 due to the two diodes 240 and 242. This results in minimal voltage drop and minimal power dissipation at switches 116 and 118 and at the respective diodes 240 and 242.

[0056] The microcontroller with components 124 and 126 can individually switch the two switches 116 and 118 on and off for testing purposes. If one of the switches 116 or 118 is switched off and a significant potential difference exists between the terminals 110 and 112 on either of the two input paths (i.e., the voltages at terminals 110 and 112 differ, for example, due to a ground offset), a voltage difference will occur across the pull-up resistors 254 and 256 and the diodes 380 and 381 (also known as backfeed protection diodes). This voltage difference can be detected by the microcontroller via the two measurement points 120 and 122 (also known as feedback inputs). Any fault that may be present can then be displayed to the driver.

[0057] The feedback from the two ground connections at terminals 110 and 112 can also be implemented in such a way that both negative and positive voltages can be measured at terminals 110 and 112. This allows for the detection of a short circuit to the battery voltage, an open circuit, and a short circuit between the internal ground potential 384 and the external ground potentials at terminals 110 and 112.

[0058] Fig. Figure 4 shows a circuit diagram of a power supply device 104 according to an exemplary embodiment. This can be an exemplary embodiment based on Fig. The device described in section 2 is involved. Fig. Device 104 shown in section 4 corresponds to the one based on Fig. 3 device shown, with the difference that the third connection 258 and the measuring points 120, 122 are connected differently.

[0059] According to this embodiment, the third terminal 258 is connected to the first line 250 via the first diode 380, the first resistor 254, and a ninth resistor 485. The first measured value 264 is read from the first measuring point 120 via the seventh resistor 382; this measuring point is located on a line connecting the first resistor 254 and the ninth resistor 485.

[0060] Accordingly, the third terminal 258 is connected to the second line 252 via the second diode 381, the second resistor 256, and a tenth resistor 486. The second measured value 266 is read from the second measuring point 122 via the eighth resistor 383; this second measuring point is located on a line connecting the second resistor 256 and the tenth resistor 486.

[0061] Fig.Figure 5 shows a flowchart of a power supply method according to an exemplary embodiment. The method can be carried out, for example, in conjunction with a power supply device described with reference to the preceding figures.

[0062] In step 591, at least one control signal is provided to an interface for the switches to keep one switch open and the other closed. In step 593, a first and a second measured value are read. In step 595, a monitoring signal is provided using the measured values.

[0063] Step 591, for example, can be performed by the control device described above, and steps 593 and 595 can be performed by the monitoring device described above.

[0064] Steps 591, 593, and 595 can be repeated, with at least one control signal being provided alternately in step 591 such that in a first phase the first switch is closed and the second switch is open, and in a second phase the first switch is open and the second switch is closed.

[0065] Steps 591, 593, and 595 can be executed during a test state of the device. When the device is being put into operation, step 591 can be executed on its own, with at least one control signal provided to close both switches. When the device is being taken out of operation, step 591 can be executed on its own, with at least one control signal provided to open both switches.

[0066] According to one exemplary embodiment, the test condition is repeated several times after the device has been put into operation, for example at predetermined time intervals.

[0067] If an embodiment includes an “and / or” connection between a first feature and a second feature, this is to be read as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature. REFERENCE MARK LIST 100 vehicles 102 Control unit 104 Device 110 first connection 112 second connection 114 Star point 116 first switch 118 second switch 120 first measuring point 122 second measuring point 124 Control unit 126 Monitoring device 128 circuit 130 Monitoring signal 132 Warning device 240 Diode (Body diode) 242 more diodes (body diodes) 244 first contact of the first switch 246 first contact of the second switch 250 first line 252 second line 254 first resistance 256 second resistor 258 third connection 260 first control signal 262 second control signal 264 first measurement 266 second measured value 268 Resistance 370 fourth connection 371 Transistor 372 Transistor 373 Transistor 374 Transistor 375 resistor 376 resistance 377 Resistance 378 resistance 380 first diode 381 second diode 382 resistor 383 Resistance 384 internal mass potential 485 resistor 486 resistor Step 591 of deployment Step 593 of the reading process Step 595 of deployment

Claims

[1] Device (104) for supplying power to a control unit (102) for a vehicle (100), wherein the device (104) has the following features: a first terminal (110) for a first power supply path, a second terminal (112) for a second power supply path and a star point (114) for connecting the first power supply path and the second power supply path, wherein the star point (114) represents a ground terminal for an electrical circuit of the control unit (102), the first power supply path and the second power supply path, wherein the two power supply paths at the two terminals (110, 112) represent redundant ground power supply paths and the terminals (110, 112) are designed as interfaces for electrically contacting the control unit (102); a first switch (116) with a first contact (244) and a second contact, wherein the first contact (244) is connected to the first terminal (110) and the second contact is connected to the star point (114), and a second switch (118) with a first contact (246) and a second contact, wherein the first contact (246) is connected to the second terminal (112) and the second contact is connected to the star point (114); a diode (240) connected in parallel to the first switch (116) between the first terminal (110) and the star point (114), and another diode (242) connected in parallel to the second switch (118) between the second terminal (112) and the star point (114), the anodes of the diodes (240, 242) being connected to the star point 114; a first measuring contact (120) for detecting a first measured value (264) representing a voltage potential of the first power supply path, and a second measuring contact (122) for detecting a second measured value (266) representing a voltage potential of the second power supply path; a control device (124) configured to keep one of the switches (116, 118) open and the other of the switches (116, 118) closed in response to a test state of the device (104); and a monitoring device (126) configured to provide a monitoring signal (130) using the first measured value (264) and the second measured value (266) when the device (104) is in the test state. [2] Device (104) according to claim 1, wherein the control device (124) is configured to close the switches (116, 118) in response to the commissioning of the device (104) and / or wherein the control device (124) is configured to open the switches (116, 118) in response to the decommissioning of the device (104). [3] Device (104) according to one of the preceding claims, wherein the control device (124) is configured to keep the first switch (116) open and the second switch (118) closed during a first phase of the test state, and to keep the first switch (116) closed and the second switch (118) open during a second phase of the test state. [4] Device (104) according to one of the preceding claims, wherein the monitoring device (126) is configured to compare the first measured value (264) and the second measured value (266) to determine a deviation between the voltage potentials of the power supply paths, wherein the monitoring signal (130) indicates the deviation. [5] Device (104) according to one of the preceding claims, wherein the first measuring contact (120) is arranged on a first connecting line (250) between the first terminal (110) and the first contact (244) of the first switch (116), and the second measuring contact (122) is arranged on a second connecting line (252) between the second terminal (112) and the first contact (246) of the second switch (118). [6] Device (104) according to any one of claims 1 to 4, comprising a third terminal (258) for providing a voltage potential, a first stub line comprising at least one first resistor (254; 485) and a first diode (380) connecting the third terminal (258) to the first terminal (110), and a second stub line comprising at least one second resistor (256; 486) and a second diode (381) connecting the third terminal (258) to the second terminal (112), wherein the first measuring contact (120) is located on the first stub line and the second measuring contact (122) is located on the second stub line. [7] Control unit (102) for a vehicle (100), comprising a device (104) according to one of the preceding claims. [8] Control unit (102) according to claim 7, wherein the star point (114) is arranged inside the control unit (102). [9] Method for monitoring a power supply for a control unit (102) according to one of claims 7 to 8 for a vehicle (100), wherein the method comprises the following steps: Providing (591) at least one control signal to an interface to the switches (116, 118) to keep one of the switches (116, 118) open and the other of the switches (116, 118) closed; and Reading (593) the first measured value (264) and the second measured value (266); and Providing (595) a monitoring signal (130) using the measured values ​​(264, 266).

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