CN112738940A

CN112738940A - Electronic control unit for a motor vehicle

Info

Publication number: CN112738940A
Application number: CN202011380570.XA
Authority: CN
Inventors: S·赫拉斯特尼克; Y·Z·张; F·B·宋; C·H·刘
Original assignee: Connaught Electronics Ltd
Current assignee: Connaught Electronics Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2021-04-30

Abstract

An electronic control unit (2) for a motor vehicle (1) comprises a processing unit (4) and a driver circuit (3), the driver circuit (3) comprising an input terminal (14b) for receiving a control signal from the processing unit (4), an output terminal (14c) for connecting a light emitting diode (9) and a switching element (23). A control terminal of the switching element (23) is connected to the input terminal (14b) to connect the output terminal (14c) to the reference terminal (17) in accordance with a control signal. The feedback terminal (14a) of the driver circuit (3) is connected to the output terminal (14c) or the reference terminal (17) and to the processing unit (4) for providing a feedback signal to the processing unit (4). The processing unit (4) is configured to identify a fault from the feedback signal.

Description

Electronic control unit for a motor vehicle

Technical Field

The invention relates to an electronic control unit for a motor vehicle, comprising a processing unit and a driver circuit for driving light emitting diodes, to a driver assistance system comprising such an electronic control unit, and to a motor vehicle comprising such an electronic control unit.

Background

Electronic control units ECUs are used for various functions of modern motor vehicles. Some functions may involve the driving of an LED, such as a parking assist application, where the LED may indicate that parking assist is active, or may feed back another status of the function to the user or driver of the vehicle. Therefore, each electronic control unit requires a driver circuit for driving the light emitting diode. Furthermore, in some cases, the light emitting diode or the driver circuit may malfunction, such as a load short circuit or open circuit condition. Such a malfunction may affect the functional safety or the respective function of the electronic control unit.

Summary of The Invention

It is an object of the present invention to provide an improved concept for an electronic control unit for a motor vehicle with a driver for driving a light-emitting diode, so that functional safety is improved.

This object is achieved by the subject matter of the independent claims. Further embodiments and preferred embodiments are subject matter of the dependent claims.

The improved concept is based on the following ideas: the driver circuit is provided with a feedback terminal for analyzing a characteristic voltage or current of the driver circuit in order to identify a fault.

According to an improved concept, an electronic control unit ECU for a motor vehicle is provided. The ECU comprises a processing unit and a driver circuit for driving the light emitting diodes LED. The driver circuit comprises an input terminal connected to the first terminal of the processing unit to receive the control signal from the processing unit. The driver circuit comprises output terminals for connecting the LEDs to the driver circuit. The driver circuit comprises a switching element, wherein a control terminal of the switching element is connected to the input terminal, and the switching element is configured and arranged to connect and disconnect the output terminal to and from the reference terminal, respectively, in dependence on a control signal, thereby driving the LEDs, in particular in order to switch the LEDs on and off, respectively. The driver circuit includes a feedback terminal connected to the output terminal or the reference terminal and to the second terminal of the processing unit to provide a feedback signal to the processing unit. The processing unit is configured to identify a failure of the driver circuit or the light emitting diode from the feedback signal.

Here and below, two components to be connected may be directly connected or indirectly connected to each other, if not otherwise stated. In particular, an electrical connection between the components may be present or may be established by operating one or more switches or further switching elements of the ECU or driver circuit, respectively. In this case, a direct connection is to be understood such that no further electrical or electronic components are arranged between the directly connected components, apart from the optional one or more switches or further switching elements, while an indirect connection is to be understood such that one or more further electrical or electronic components are arranged between the indirectly connected components, apart from the optional one or more switches or further switching elements.

The reference terminal may for example correspond to a ground terminal of the driver circuit or the ECU, respectively. Alternatively, the reference terminal may provide a predetermined constant reference voltage.

The processing unit is configured to generate a control signal. Depending on the value of the control signal, the switching element is in a conducting or closed state, or in a non-conducting or substantially non-conducting or open state. In other words, when the switching element is open, no or almost no current flows between the first terminal of the switching element and the second terminal of the switching element, whereas in the closed state, a current may flow between the first terminal and the second terminal of the switching element. By closing and opening the switching elements, respectively, the driver circuit can drive the LEDs accordingly by switching on and off, respectively.

The switching element may for example comprise a transistor. In this case, the control signal may correspond to a base signal or base voltage or gate signal or gate voltage of the transistor, depending on the specific implementation of the transistor. In particular, the control signal may be a digital or binary signal. The switching element may be open if the value of the control signal takes a first value, e.g. a logic 0, and closed if the control signal takes a second value, e.g. a logic 1, or vice versa.

The first terminal of the switching element is connected, in particular indirectly, to the output terminal, while the second terminal of the switching element is connected, in particular indirectly or directly, to a reference potential. In the case of a bipolar transistor, the first and second terminals of the switching element may correspond to collector and emitter terminals, respectively, and in the case of a field effect transistor, the first and second terminals of the switching element may correspond to source and drain terminals, respectively.

The feedback signal may for example represent a characteristic voltage or current of the driver circuit, which may be analyzed by the processing unit in order to identify a fault. Wherein identifying a fault may be understood as causing the processing unit to determine that there is any fault and/or causing the processing unit to also determine the type or category of fault.

For example, according to a practical implementation of the driver circuit, in case of absence of a fault, it may be determined that the feedback signal is within one or more normal operating ranges. The feedback signal may be situated, for example, in a first normal operating range when the switching element is closed, and in a second normal operating range when the switching element is open.

Thus, in the event that the processing unit determines that the feedback signal is outside of one or more normal operating ranges, it may identify that a fault is present. Further, the processing unit may also identify the type or class of fault by determining whether the value of the feedback signal is within one or more characteristic fault ranges.

The LED may be connected to an output terminal of the driver circuit through a first terminal of the LED. The second terminal of the LED may then be connected to a supply terminal providing a supply voltage, for example the battery voltage of a motor vehicle battery. In case a positive potential relative to the potential on the reference terminal is applied to the second terminal of the LED, the first terminal of the LED may correspond to the anode of the LED and the second terminal of the LED may correspond to the cathode of the LED, whereas in case a negative voltage relative to the potential on the reference terminal is applied to the second terminal of the LED is a negative voltage, then vice versa.

If the processing unit has identified a fault, a diagnostic fault code DTC may be set, for example, accordingly.

By means of the improved concept, a particularly simple structure for an electronic control unit is provided, which has a driver circuit for driving the LEDs and a diagnostic function for identifying a malfunction of the driver circuit or the LEDs. The components of the driver circuit, in particular the switching elements, as well as additional components, such as resistors, capacitors, etc., may be implemented as discrete electronic components. Therefore, it is not necessary to use an integrated circuit as part of the driver circuit. Thus, costs and PCB space may be saved. Further, this reduces the amount of work to define the driver circuit and the ECU, respectively. Meanwhile, by connecting the feedback terminal as described above to the driver circuit and the processing unit, functional safety can be improved.

According to several embodiments of the electronic control unit, the driver circuit is realized by discrete electronic components only, in particular without an integrated circuit.

According to several embodiments, the processing unit comprises a microcontroller unit configured to generate the control signal and to provide the control signal to the input terminal of the driver circuit. The microcontroller unit is further configured to receive a feedback signal from a feedback terminal of the driver circuit and to identify a failure of the driver circuit or the light emitting diode according to the feedback signal.

The microcontroller unit may for example comprise an analog-to-digital converter ADC connected to the second terminal of the processing unit or microcontroller, respectively, to receive the feedback signal from the feedback terminal of the driver circuit, wherein the ADC is configured to generate the digital feedback signal based on the feedback signal. The microcontroller unit, e.g. a processor of the microcontroller unit, may be configured to identify a failure of the driver circuit or the LED from the digital feedback signal.

According to several embodiments, the processing unit, in particular the microcontroller unit, is configured to determine whether the voltage represented by the feedback signal lies within at least one predetermined voltage range, and to determine that a fault exists if the voltage lies within at least one voltage range. Wherein at least one voltage range is in particular outside one or more normal operating ranges.

According to several embodiments, the processing unit, in particular the microcontroller unit, is configured to determine that the fault is of a first type if the voltage represented by the feedback signal is within a first voltage range of the at least one voltage range and of a second type if the voltage represented by the feedback signal is within a second voltage range of the at least one voltage range.

Wherein the first or second type of fault may include one or more subtypes. For example, two different types of faults may result in the same effect on the feedback signal.

For example, a first type of fault may correspond to a short circuit of the output terminals of the driver circuit with the supply voltage of the LEDs, in particular the battery voltage. In this case, for example, the absolute value of the voltage represented by the feedback signal may be higher than in normal operation.

The second type of fault may for example comprise two subtypes, namely a short circuit of the output terminal to a reference terminal, in particular to ground, and an open load condition at the output terminal. In both cases, the absolute value of the voltage represented by the feedback signal may be close to zero.

Depending on the type of fault identified, the processing unit may set different DTCs for diagnosis.

According to several embodiments, the driver circuit is designed as a low-side driver circuit.

In other words, the potential at the power supply terminal to be connected to the LED is positive with respect to the potential at the reference terminal. In particular, the reference terminal may be connected to two grounds and the supply voltage may be positive. This means that the driver circuit can ground the LED by closing the switching element.

According to several embodiments, the processing unit, in particular the microcontroller unit, is configured to generate the control signal depending on the feedback signal.

In particular, the processing unit may generate a control signal such that the switching element is opened in case the processing unit identifies a fault.

Alternatively, the value of the feedback signal may correspond to a characteristic current of the driver circuit, which may be related to the current through the LED. Therefore, the processing unit may detect a change or a drop in the battery voltage or the power supply voltage according to the feedback signal. As a result, the control signal can be adapted to the variations in the supply voltage to keep the emitted light power of the LED approximately constant. This may be achieved, for example, by modulating the control signal according to pulse width modulation PWM.

According to several embodiments, the processing unit is configured to generate the control signal as a PWM signal, wherein a duty cycle of the PWM signal depends on the feedback signal.

According to several embodiments, the switching element comprises a field effect transistor, such as a MOSFET.

PWM can be conveniently realized by using a field effect transistor for the switching element.

According to several embodiments, the feedback terminal is connected between the reference terminal and the second terminal of the switching element.

According to several embodiments, the driver circuit comprises a discharge protection circuit for protecting the driver circuit and/or the light emitting diode from electrostatic discharge, wherein the discharge protection circuit is arranged between the output terminal and the second terminal of the switching element.

The discharge protection circuit may for example comprise a first branch connected between the output terminal of the driver circuit and the reference terminal, the first branch comprising a capacitor. In some embodiments, the discharge protection circuit may comprise a second branch connected between the output terminal of the driver circuit and the reference terminal, wherein the second branch comprises the transient voltage suppressor TVS. In this way, a simple and effective ESD protection can be achieved.

According to several embodiments, the driver circuit comprises a reverse polarity protection unit arranged between the switching element and the output terminal. The reverse polarity protection unit may include a zener diode.

According to several embodiments, the electronic control unit comprises a digital signal processor DSP connected to the processing unit. The electronic control unit comprises a video interface connected to the digital signal processor and configured to receive video data from a camera system, in particular of a motor vehicle. The digital signal processor is configured to generate a further control signal in dependence on the video data, and the processing unit is configured to generate the control signal in dependence on the further control signal.

The digital signal processor may for example be implemented as a system on chip SOC. In particular, the processing unit may generate the control signal to switch the switching element on or off in dependence on the further control signal, or may determine the duty cycle of the pulse width modulated signal in dependence on the further control signal.

According to several embodiments, the video interface comprises a deserializer.

According to several embodiments, the processing unit comprises a status input terminal for receiving a status signal, and the processing unit is configured to generate the control signal in dependence of the status signal.

For example, the status input terminal may be connected to a user input device of the motor vehicle, such as a button. The status signal may then depend on a user input to the user input device. For example, a user may activate a function associated with the electronic control unit, such as an automatic parking function, by means of a user input.

In some embodiments, the status input terminal is connected to an electronic control unit or a sensor device of the motor vehicle, for example a light sensor. In such embodiments, the brightness of the LED may be controlled in dependence on a status signal, which may be indicative of ambient light conditions. In particular, the duty cycle of the PWM signal may be adjusted according to the status signal.

According to an improved concept, a driver assistance system, in particular an advanced driver assistance system ADAS, is also provided, comprising an electronic control unit according to the improved concept.

In particular, driver assistance systems are designed as automatic parking assistance systems for vehicles.

According to an improved concept, a motor vehicle comprising an electronic control unit or a driver assistance system according to the improved concept is also provided.

Other features of the invention will be apparent from the claims, the drawings and the accompanying description. The features and feature combinations mentioned above in the description and those mentioned below in the description of the figures and/or shown in the figures only can be included in the concept defined by the improvements not only in the respectively specified combination but also in other combinations. Thus, embodiments of the improved concepts are contemplated and disclosed, which may not be explicitly shown or described in the figures, but rather result from a combination of features separate from the illustrated embodiments. Embodiments and combinations of features not having all the features of the claims initially claimed may be embraced by the improved concepts. Furthermore, the improved concept may encompass embodiments and combinations of features that depart from or that are set forth in the following relationships.

Drawings

Fig. 1 shows a schematic view of a motor vehicle comprising an exemplary embodiment of an electronic control unit according to the improved concept;

FIG. 2 shows a schematic block diagram of a further exemplary embodiment of an electronic control unit according to the improved concept;

FIG. 3 shows a schematic block diagram of portions of a further exemplary embodiment of an electronic control unit according to the improved concept; and is

Fig. 4 shows a circuit diagram of a driver circuit of a further exemplary embodiment of an electronic control unit according to the improved concept.

Detailed Description

Fig. 1 shows a motor vehicle 1 with an exemplary embodiment of an ECU 2 according to the improved concept. For example, the vehicle 1 may be equipped with a driver assist function, such as a parking assist function. To this end, the vehicle 1 may comprise one or

more cameras

10a, 10b, 10c, 10d connected to the ECU 2 and a head unit 5 having a screen 6 and a plurality of control buttons 7 connected to the ECU 2. The control buttons 7 may include an activation button 8 with an integrated LED 9. One or more images generated by the

cameras

10a, 10b, 10c, 10d may be displayed on the screen 6. The ECU 2 includes a driver circuit 3 for driving the LEDs 9 and a processing unit 4 connected to the driver circuit 3.

To activate the parking assist function, the vehicle driver can operate the activation button 8. Then, the ECU 2 may turn on the LED 9 to indicate that the automatic parking assist function is activated. When each automatic parking task is completed, the ECU 2 may turn off the LED 9.

It is emphasized that the described auxiliary functions of the vehicle 1 are merely one exemplary application of the ECU 2 according to the improved concept, according to the improved concept. The ECU 2 may also be applied to other applications involving driving the LEDs 9.

Fig. 2 shows a block diagram of an ECU 2 according to the improved concept, for example, the ECU 2 used in the vehicle 1 of fig. 1.

The ECU 2 comprises a processing unit 4, which may be designed as a microcontroller unit; and a driver circuit 3 for driving the light emitting diode 9, which may be coupled to the ECU 2 via a main connector 13 and an output terminal 14c of the driver circuit 3, the output terminal 14c being connected with the main connector 13.

The driver circuit 3 further comprises input terminals 14b connected to respective terminals 15b of the processing unit 4 for receiving control signals. The driver circuit 3 includes a switching element 23, wherein a control terminal of the switching element 23 is connected to the input terminal 14 b. The switching element 23 is configured to connect the output terminal 14c to the ground terminal 17 so as to turn on the connected LED 9, and disconnect the output terminal 14c from the ground terminal 17 so as to turn off the LED 9 according to control. A signal. Wherein the LED 9 may be connected to a battery terminal 16 for providing a battery voltage, as shown in the block diagram of fig. 3.

The driver circuit 3 further comprises a feedback terminal 14a connected to a respective terminal 15a of the processing unit 4 for providing a feedback signal from the driver circuit 3 to the processing unit 4. The feedback terminal 14a is connected to the circuitry of the driver circuit 3 such that the feedback signal represents a characteristic voltage and/or current of the driver circuit 3. For example, the feedback terminal 14a may be connected to the driver circuit 3 between the switching element 23 and the ground terminal 17. Alternatively, the feedback terminal 14a may also be connected between the switching element 23 and the output terminal 14 c.

The processing unit 4 receives a feedback signal from the driver circuit 3 and determines a value of the feedback signal, e.g. a voltage represented by the feedback signal. Depending on the battery voltage, the voltage represented by the feedback signal (which may also be denoted as feedback voltage) lies within one or more certain known ranges of normal operation of the driver circuit 3 and the LEDs 9. The processing unit 4 may determine whether the feedback voltage is outside these known normal operating ranges to determine whether there is a fault with the driver circuit 3 or the LED 9. For example, when the output terminal 14c is short-circuited to the ground terminal 17 or to the battery terminal 16, it may be identified as a corresponding fault by the processing unit 4 based on the feedback voltage. Another example of a fault is an open load condition at output terminal 14 c.

In some embodiments, the processing unit 4 is configured to distinguish between different types of faults according to the feedback voltage. For example, in the case of an open load state at the output terminal 14c and in the case of a short circuit with the ground terminal 17, the feedback voltage may be approximately zero. On the other hand, in the case of a short circuit with the battery terminal 16, the feedback voltage may be larger than that in normal operation.

Fig. 4 shows a schematic circuit diagram of an exemplary embodiment of a driver circuit 3 of an ECU 2 according to the improved concept, which driver circuit 3 is used, for example, in the ECU 2 described with respect to fig. 1 to 3.

In the embodiment of fig. 4, the switching element 23 comprises a MOSFET, the gate terminal of which is connected to the control terminal 14 b. In fig. 4, the MOSFET is designed as an n-channel enhancement MOSFET. However, other types of MOSFETs or even other types of field effect transistors may be used. In the embodiment of the n-type enhancement MOSFET, its source terminal is connected to the ground terminal 17, and its drain terminal is connected to the output terminal 14 c. By generating the control signal accordingly, the processing unit 4 can thus open and close the switching element 23 to drive the LED 9, respectively.

The driver circuit 3 may comprise a resistor 22 connected to the drain terminal and/or a resistor 24 connected between the ground terminal 17 and the source terminal of the switching element 23. These

resistors

22, 24 may be used to define the current through the LED 9.

Further resistors

25, 27 may for example be coupled between the feedback terminal 14a and the source terminal and/or between the ground terminal 17 and the input terminal 14 b. Fig. 4 also shows

capacitors

26, 28 coupled between ground terminal 17 and

terminals

14a, 14b, respectively.

In some embodiments, the processing unit 4 may be configured to generate a control signal as a PWM signal in order to control the emitted light intensity of the LEDs 9. The duty cycle of the PWM signal may be determined, for example, by the processing unit 4 from the feedback signal, which may indicate the LED current. Alternatively or additionally, the duty cycle may be determined by a sensor input of a sensor (not shown) coupled to the processing unit 4, for example a light sensor, arranged to determine an ambient light level within the cabin of the motor vehicle 1.

In some embodiments, the driver circuit 3 may comprise a zener diode 21 connected between the switching element 23 and the output terminal 14c, which may be used as reverse polarity protection. In some embodiments, the driver circuit 3 may comprise an ESD protection circuit 18 for protecting the driver circuit 3 and/or the LEDs 9 from high voltages caused by ESD events. The ESD protection circuit 18 may, for example, include a capacitor 19 coupled between the output terminal 14c and the ground terminal 17. Alternatively or additionally, the ESD protection circuit 18 may include a transient voltage suppressor 20 connected between the output terminal 14c and the ground terminal 17.

As described, and in particular with respect to the figures, the improved concept provides an architecture for an ECU having a driver circuit for driving LEDs with particularly low complexity and allowing the driver circuit to be diagnosed for faults in a simple and convenient manner. Thus, the improved concept may help to reduce the cost of the ECU and reduce the assembly space of the driver circuit.

Claims

1. An electronic control unit (1) for a motor vehicle, the electronic control unit (2) comprising a processing unit (4) and a driver circuit (3) for driving light emitting diodes (9),

it is characterized in that the preparation method is characterized in that,

-the driver circuit (3) comprises:

-an input terminal (14b) connected with the processing unit (4) to receive a control signal;

-an output terminal (14c) for connecting the light emitting diode (9) with a driver circuit (3);

-a switching element (23), wherein a control terminal of the switching element (23) is connected with the input terminal (14b), and the switching element (23) is configured to connect the output terminal (14c) with a reference terminal (17) depending on a control signal for driving the light emitting diode (9); and

-a feedback terminal (14a) connected with said output terminal (14c) or with said reference terminal (17) and with said processing unit (4) to provide a feedback signal to said processing unit (4); and is

-the processing unit (4) is configured to identify a failure of the driver circuit (3) or the light emitting diode (9) from a feedback signal.

2. The electronic control unit according to claim 1,

it is characterized in that the preparation method is characterized in that,

the processing unit (4) comprises a microcontroller unit configured to

-generating a control signal and supplying the control signal to an input terminal (14b) of the driver circuit (3);

-receive a feedback signal from a feedback terminal (14a) of the driver circuit (3); and

-determining a malfunction of the driver circuit (3) or the light emitting diode (9) from a feedback signal.

3. Electronic control unit according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the processing unit (4) is configured to determine whether the voltage represented by the feedback signal lies within at least one predetermined voltage range, and to determine that a fault exists if the voltage lies within the at least one voltage range.

4. The electronic control unit according to claim 3,

it is characterized in that the preparation method is characterized in that,

-the processing unit (4) is configured to determine that the fault is of a first type if the voltage represented by the feedback signal is within a first voltage range of the at least one voltage range; and is

-determining that the fault is of the second type if the voltage represented by the feedback signal is within a second voltage range of the at least one voltage range.

5. Electronic control unit according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the driver circuit (3) is designed as a low-side driver circuit (3).

6. Electronic control unit according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the processing unit (4) is configured to generate the control signal in dependence on the feedback signal.

7. The electronic control unit according to claim 6,

it is characterized in that the preparation method is characterized in that,

the processing unit (4) is configured to generate the control signal as a pulse width modulated signal, wherein the duty cycle of the pulse width modulated signal depends on the feedback signal.

8. Electronic control unit according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the switching element (23) comprises a field effect transistor.

9. Electronic control unit according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

-said switching element (23) comprises a first terminal connected to said reference terminal (17); and is

-the feedback terminal (14a) is connected between the reference terminal (17) and a first terminal of the switching element (23).

10. Electronic control unit according to one of the preceding claims,

it is characterized in that

-said switching element (23) comprises a second terminal connected with said output terminal (14 c); and is

-the driver circuit (3) comprises a discharge protection circuit (18) for protecting the driver circuit (3) and/or the light emitting diode (9) from electrostatic discharge, wherein the discharge protection circuit (18) is arranged between an output terminal (14c) and a second terminal of the switching element (23).

11. Electronic control unit according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

-said electronic control unit (2) comprises:

-a digital signal processor (11) connected to the processing unit (4); and

-a video interface (12) connected to the digital signal processor (11) and configured to receive video data from the camera system (10a, 10b, 10c, 10 d);

-the digital signal processor (11) is configured to generate a further control signal from the video data; and

-the processing unit (4) is configured to generate the control signal in dependence on the further control signal.

12. The electronic control unit according to claim 11,

characterized in that the video interface (12) comprises a deserializer.

13. Electronic control unit according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the processing unit (4) comprises a status input terminal (14b) for receiving a status signal, and the processing unit (4) is configured to generate a control signal in dependence of the status signal.

14. Driver assistance system comprising an electronic control unit (2) according to one of the preceding claims.

15. Motor vehicle comprising an electronic control unit (2) according to one of claims 1 to 13.