Control circuit and actuator unit with a control circuit and method for operating a control circuit

Abstract

The invention relates to a control circuit (2a) with a control unit (20) for operating an electronically controllable device (2b) connected thereto. The control unit (20) comprises at least two different signal processing modules (22, 23) connected via a common signal connection (11). Furthermore, an activation unit (21) is provided which, depending on a signal type of a control signal (S) detected via the signal connection (11), can activate one of the two signal processing modules (22, 23) for signal processing. Furthermore, the control circuit (2) has a switching unit (30) for at least one of the two signal processing modules (22, 23). In the activated state, the switching unit (30) can connect the signal connection (11) to a predetermined reference potential.To activate the switching unit (30), the activation unit (21) can control the switching unit (30) depending on the determined signal type and depending on the activated signal processing module (22, 23).

Description

The invention relates to a control circuit for an electronically controllable device. The invention also relates to an actuator unit for a motor vehicle having an electronically controllable device and having a corresponding control circuit. The invention also relates to a method for operating a corresponding control circuit. The control circuit according to the invention is to be used for controlling or operating the electronic device. The control circuit can thus be understood as control electronics or driver circuit for the device, in particular an actuator of the device. For example, such a control circuit can be used in a motor vehicle for controlling an actuator or a servomotor or a water pump. A servomotor can be used, for example, for a seat adjuster, a windshield wiper, a window lifter or another exemplary application in the motor vehicle.For control purposes, the control circuit can acquire or receive a respective control signal from a control device, such as a central computing device of the motor vehicle. The control signal may comprise a control command, such as "window on" for the device. The control circuit may evaluate or analyze the control signal for the device. For example, the control circuit can translate the included control command and determine assigned settings or parameters for the device or its actuator. The settings can be transmitted to the device by the control circuit, for example, by means of a setting signal. The settings may include, for example, a desired speed and / or current or other known setting for controlling the device.For the signal transmission, different signal types or signal formats are possible, for example, in the vehicle sector. The device may be accessible for a specific type of signal, for example. In older motor vehicles, the control is effected, for example, via a so-called pulse width modulation (PWM). The control signal is thus provided as a PWM signal (signal type PWM). Control commands encoded in the control signal are defined, for example, by way of the duty cycle. For example, a duty cycle of 10 to 20 percent may mean "window up", while the duty cycle of 70 to 80 percent means "window up". The control circuit can evaluate the duty cycle and, from this, specify settings for the device assigned, for example, by means of the setting signal.In more recent motor vehicles, the communication or control takes place, for example, by means of a so-called BUS, also called FieldBUS. A BUS is a known system for data transmission between a plurality of subscribers via a common transmission path. There are different types of BUS which differ substantially in their signal shape or signal formatting. In motor vehicle communication, for example, a local interconnect network (LIN) BUS can be used. The control signal is thus transmitted as a LIN signal (signal type LIN). LIN is a serial communication system known per se. That is, the LIN-BUS has the advantage that many different devices can be addressed via a common signal connection. The distinction between the devices is made by the transmission and evaluation of an address, which is also called an identifier.Another possibility for control is, for example, the use of a controller area network (CAN) BUS. This is also a standardized serial communication system known per se.The control of devices in a motor vehicle by means of various communication types, such as CAN, LIN and PWM, is known, for example, from DE 10 2017 203 824 A1. In this case, a controller checks, for example, whether a water pump motor has a communication error. For this purpose, a test signal is transmitted to the water pump motor and a feedback signal fed back by the water pump motor is evaluated with the controller.Assemblies are also known which combine different types of communication, such as LIN and PWM. Such assemblies have the advantage that they can be used universally, i.e. for many different devices for control purposes.The integration of a LIN and PWM function into a single component is known, for example, from DE 10 2007 012 708 A1. In this case, a device connection of a transceiver circuit is switched through either to a LIN line or to a PWM line by means of a switching device.DE 10 2017 121 175 A1 furthermore discloses a control circuit having two different interfaces which are connected to one another via a common control input. A detection unit detects whether a control signal valid for the respective interface is present at the control input and then activates the corresponding interface. The interface may be, for example, a PWM and a LIN interface.Furthermore, the publication CN 115 157 954 A describes a method for processing blower control data for motor vehicles, a blower control system and a motor vehicle, the publication DE 10 2017 109 862 A1 describes a programmable plug, and the publication DE 10 2010 053 304 B4 describes a control device having an input configured for processing signals of different sensor types and methods for adapting a control device.It is the object of the present invention to further develop a control circuit, as is known from the prior art, which is designed for processing different signal types, in such a way that signal transmission conforming to the signal type can be improved.The object is achieved by the subject matters of the independent claims. Advantageous refinements of the invention are disclosed by the dependent patent claims, the description and the figures.The invention is based on the recognition that when using a control circuit or driver circuit which can process different signal types, differences in a circuit may be necessary to obtain a valid control signal for the device to be controlled. In the present case, the wiring means in particular upstream components or a pre-wiring. For example, there are control circuits which are designed to process PWM signals and have an integrated LIN transceiver. For PWM processing, however, an additional coupling resistor, in particular a pull-up or pulldown resistor, is required in order to set or pull a signal input to a defined reference level. Without the additional coupling resistor, a level or potential at the signal input can be floating or undefined. This is due to the fact that a so-called open-X output can be present at the signal input without the coupling resistor. Here, "X" represents, for example, collector or drain. Such an open-X output is known per se when using semiconductor switches in electronic assemblies or integrated circuits. When there is a floating potential, the control circuit cannot receive the PWM signal. However, such a coupling resistor may violate requirements of the LIN standard. In order to implement these circuit specifications, the invention is intended to provide a possibility for switching between different circuits for the control circuit.For this purpose, the invention proposes a control circuit or control electronics for an electronically controllable device. The control circuit comprises one, in particular at least one, signal connection. The signal connection is designed to receive or acquire a respective control signal from at least one control device connected or connected thereto. In addition, the control circuit also comprises a control device. The control device is designed for processing, i.e., for example, for evaluating and / or recognizing the respective control signal. For this purpose, the control device comprises at least two different signal processing modules, for example a LIN module and a PWM module, which are connected or coupled to the common signal connection. For this purpose, the signal processing modules can, for example, first be led to a common control input of the control unit, which can then be coupled to the signal connection.Furthermore, the control circuit comprises an activation unit. The activation unit has in particular two functions. On the one hand, the activation unit is designed to ascertain, i.e. to determine or recognize, a signal type of the respective control signal according to a predefined ascertainment criterion. This means that the activation unit can distinguish between a plurality of different, in particular two different, signal types of the control signal. On the other hand, the activation unit is designed to activate or enable (exactly) that one of the signal processing modules which is assigned to the determined signal type. That is, the activation unit can activate the signal processing module intended for the signal type depending on the signal type. Thus, the signal processing module which is configured or permitted for processing the signal type can be activated. The activated signal processing module is then used to process the control signal. Preferably, the remaining signal processing modules that are not assigned to the determined signal type are then deactivated. They cannot therefore be used for signal processing.The signal processing modules can thus differ in their suitability for processing different signal types of a control signal. Each of the modules can be configured for signal processing of a signal with a different or different signal type, for example. The assignment of the signal type to the respective signal processing module can be stored, for example, in an assignment rule retrievable for the activation unit. The allocation rule can be implemented, for example, in an allocation table or look-up table.Processing the control signal may comprise determining or translating the control signal into a setting signal. For this purpose, for example, a device setting for the electronically controllable device can be determined or assigned to the respective control command comprised by the control signal. The control circuit can then send or transmit the setting signal to the device, in particular its actuator, for example by means of a further signal connection. The respective setting can be, for example, a setpoint rotational speed or a setpoint torque or a current intensity or an electrical voltage or another operating parameter for controlling an actuator. The further signal connection can form an output connection for connecting or coupling the electronic device to be controlled.In order to enable signal processing conforming to the signal type, the control circuit also comprises a switching unit. The switching unit is in particular assigned to exactly one of the at least two signal processing modules. That is, the switching unit may be shared or operated with only one of the signal processing modules. The operation thereof is in particular impermissible for the other signal processing modules.The switching unit is designed to connect, i.e. to connect or couple, the signal connection to a predefined reference potential or reference potential in an activated state. By the connection, the reference potential can be provided or made available to the signal terminal. A potential that can be tapped off at the signal terminal is thus set to the reference potential.In a deactivated state, on the other hand, the switching unit disconnects the signal terminal from the predefined reference potential. In the present case, connecting and disconnecting means in particular an electrical connection or connection and disconnection or decoupling. Connecting means in particular that a current flow or a power transmission is made possible. By contrast, disconnection means that a current flow or a transmission of energy is interrupted and is thus blocked.The above-mentioned activation unit is now designed to activate or deactivate this switching unit depending on the determined signal type and depending on the activated signal processing module. It can thus put the switching unit into the activated state or deactivated state. In particular, the switching unit remains or is activated only when, according to the detected signal type, the signal processing module assigned to the switching unit is activated or selected for activation. If, on the other hand, according to the detected signal type, the switching unit is not assigned to the switching unit, i.e. a signal processing module different from the assigned signal processing module is activated or selected for activation, the switching unit remains or will deactivate. To activate the switching unit and the associated signal processing module, the activation unit can provide a respective or common activation signal. The activation can thus take place or be triggered substantially simultaneously.Thus, interface-compliant circuitry may be implemented depending on the type of signal and the signal processing module selected. Thereby, a control circuit can be provided which satisfies requirements regarding various types of communication or signal types. The control circuit can thus be used universally and is compliant with internal specifications or communication standards. The control circuit can therefore also be used, if required, in inventory projects, that is to say, for example, motor vehicles which have previously used PWM communication, since, for example, a connection specification or pin occupancy for the interconnection does not need to change. Moreover, the changeover to the modern LIN interface in inventory projects is also facilitated. This makes it possible to achieve further cost advantages, since a plurality of devices having only one connection can be controlled by means of LIN communication compared to PWM communication.As mentioned at the beginning, the control circuit can be, for example, control electronics or driver circuits for the device. The control circuit and the device can be present together in a so-called actuator unit, i.e. they form the latter.The electronically controllable device can be in particular a device which can be controlled or operated electronically, that is to say with the control signal. The electronic device can comprise an actuator or form an actuator, for example. The actuator can be, for example, an actuating drive or a servomotor or a valve or another electrically controllable actuating element. The corresponding servomotor can be used, for example, in a motor vehicle for vehicle seat adjustment or for a window lifter. Alternatively, the use for a water pump of a cooling system is conceivable.The control device may be a central processing unit (ECU) or a central processing unit (CPU). In the vehicle field, the control device may be referred to as an on-board central computer, for example.The control device and the control circuit may be operated in a so-called master-slave configuration or controller-target configuration. Thus, the control device may be a higher-order functional unit (controller) compared to the control circuit, while the control circuit may form one of a plurality of lower-order functional units (target), for example.Preferably, the signal transmission between the control device and the control circuit can be configured bidirectionally. That is, data can be received from the control device and / or transmitted to it by means of the control circuit.The respective signal connection of the control circuit can in the present case be an electrical connection for data transmission. The signal connection can comprise, for example, a signal line internal to the control circuit, that is to say a wiring or wiring with the components or components of the control circuit. The signal connection can be formed in a connection contact, i.e. a means for connecting to the control device and / or the device from the control circuit. The signal terminal contact may form, for example, one of a plurality, such as three or four, terminals of an input terminal of the control circuit. The input connection can form a wired or physical or wireless interface component. With a complementary or corresponding interface component of the control device, the input connection can form an interface for signal transmission between the control circuit and the control device. For this purpose, the control device can be connected to the input connection or coupled to the latter. The connection contacts can be designed, for example, as plug contact according to a predefined standard for a plug connection, such as, for example, according to the IEC 60 309 standard or the SCART standard. Alternatively, the connection contacts can be designed, for example, as a radio connection according to a predefined standard for wireless communication, for example, WLAN, Bluetooth, near-field communication (NFC) or mobile radio.In addition to the signal connection contact, a positive connection and a negative connection, for example, can be provided as further connection contacts of the input connection. A positive potential or permanent plus of an electrical network in which the control circuit is used can be present or carried, for example, on the positive connection. A negative potential or ground potential (ground) or permanent minus of the electrical network can be led or applied to the negative terminal. The positive potential and negative potential can be predefined or provided by an energy store or battery, for example. This positive or negative potential of the electrical network can be the reference potential to which the signal terminal is connected in a signal-type-dependent manner.The signal connection can be a multifunction connection or a multifunction connection. That is, the signal terminal may transmit signals of different types. The signal type here describes the form or format in which the control signal is transmitted. Thus, for example, the communication type or communication standard may be described. The control signal may be distinguishable based on the type of signal. For example, each signal type can have characteristic features or properties, whereby a clear assignment is possible. Such a feature can be, for example, a level, an amplitude, a pulse duration, a frequency, a duty cycle, a repetition rate, a message structure or another signal property known per se. In the present case, it is possible to distinguish, for example, between two different types, namely the signal type LIN and the signal type PWM, as described at the beginning. Of course, the control circuit described here can also be used for further signal types, for example CAN or Ethernet or Flexray, which are not described in more detail here.The control signal can be a digital signal, in particular a binary signal, which is switched between two different levels for message transmission. The levels can be defined, for example, by the reference potentials of the electrical network. For example, a "high" level may be associated with the positive potential, while a "low" level may be associated with the negative potential. In a network with a 12 volt rated voltage, a signal level with the "low" state can be detected, for example, whenever the measured value is less than 7 volts. In contrast, a signal level with the "high" state may be detected, for example, whenever the measured value is greater than 7 volts. The modulation or composition of the high and low levels is in particular signal-type-dependent.The control device can be designed as a data processing device or processor device. For signal processing, the control device can have at least one microprocessor and / or at least one microcontroller and / or at least one FPGA (field programmable gate array) and / or at least one DSP (digital signal processor).The signal processing modules can each be implemented as a software program or algorithm in the control device. Alternatively, the signal processing modules can be implemented in terms of circuitry, in particular as a hardware circuit, for example as a logic circuit. The signal processing modules process the control signal depending on the type of signal. That is, each of the signal processing modules is specialized for a particular type of signal. Processing in the present case means in particular an evaluation and / or adaptation and / or a reaction to the control signal. For this purpose, the respective processing module can, for example, recognize the signal shape and, in particular, initiate a reaction thereto. To name just a few examples, for example, operating parameters of the device may be read out and stored, errors detected, new operating parameters generated for the device and sent as the adjustment signal, etc.The switching unit can be formed as an integral component of the control unit or as a separate component from the control unit. By configuring it as a separate component, a power loss in the control device can be minimized, for example. The switching unit is designed to be switchable. That is, it can be switched at least between two switching states, namely an switched-on switching state (activated state) and a switched-off switching state (deactivated state). The switching of the switching unit can be implemented by means of a switching signal or activation signal of the activation unit. By means of the switching unit, a correct logic input level can be guaranteed for an open contact, in this case the signal terminal, by the reference potential being applied to the signal terminal by connection to the respective reference potential.The activation unit can recognize the signal type required for controlling the connected device and, for this purpose, activate or deactivate the corresponding signal processing module and, if necessary, the switching unit depending on the signal type. Thus, the activation unit may select the appropriate processing module for the control signal for controlling the device. The activation unit can be comprised, for example, by the control unit and can be designed, for example, as a module of the control unit. This means that its functionality can be implemented, for example, as an algorithm or software program in the control device. Alternatively, the activation unit can be designed as a separate component from the control unit. The activation unit can comprise a microcontroller or microprocessor, for example, for implementing the functionality.In addition, the activation unit is designed to determine the signal type, according to the determination criterion, to alternately activate and deactivate the switching unit cyclically, i.e. periodically or repeatedly in a predefined detection time interval, and to check the control signal in the activated and deactivated state in each case for an identification feature assigned to the respective signal type. That is, the control circuit may be cyclically switched between the LIN mode (switching unit deactivated) and the PWM mode (switching unit activated), for example. For this purpose, the switching element can be switched on or off cyclically for a defined time period in each case until a valid communication is detected. It is particularly advantageous if the switching unit is initially deactivated at the beginning of the detection time interval. Thus, LIN-compliant circuitry may be realized.The identification feature can be, for example, the aforementioned characteristic signal property, such as a signal level or a frequency, or a different feature in the signal profile typical of a respective signal type. For example, a so-called synchronization pause (sync break) or an identifier can be checked or queried for ascertaining the signal type. These are special message parts or sections which are typical of a LIN signal and do not occur during PWM communication.The invention also includes embodiments which result in further advantages.According to one embodiment, at least a first of the at least two signal processing modules is configured to process the respective control signal as a PWM signal. That is, the first signal processing module is a PWM module, and forms a PWM interface. Thus, when using the first signal processing module, the connected device can be controlled by means of pulse width modulation. The control commands transmitted by means of the control signal are encoded in terms of their pulse width, in particular in terms of their duty cycle. How a PWM module can be implemented in a control device is known per se.According to a further embodiment, a second of the at least two signal processing modules is configured to process the respective control signal according to the LIN standard. The LIN standard, also called the LIN specification, is described, for example, in the standard ISO 17987. Thus, the control signal can be a LIN signal, i.e. a signal whose signal profile or format is predefined for transmitting a message or a control command according to the LIN standard. The device to be controlled can thus be controlled by means of LIN communication. The control commands transmitted by means of the control signal can be transmitted in the form of a digital message with a format predefined according to the LIN standard in encoded form. The second signal processing module can also be referred to as a LIN module or so-called LIN transceiver.According to a further embodiment, the above-mentioned switching unit is assigned to the first of the at least two signal processing modules. That is, the switching unit is associated with the PWM module.As a result, for the PWM communication by means of the switching unit, the signal connection can be set to the desired logic input level, that is to say the reference potential. On the basis of this, the PWM module can adjust the input level such that the desired control command can be decoded from the control signal. For example, the input level, which can be measured between the control terminal and the negative potential, for example, can be drawn from the positive potential to the negative potential or vice versa, i.e., coupled thereto. The change between the positive and the negative potential can take place in the desired duty cycle, so that the PWM signal results as a control signal.According to a further embodiment, the switching unit comprises a coupling resistor and a switching element. In this case, the signal terminal can be coupled via the coupling resistor to the reference potential, that is to say, for example, the positive or negative potential. The switching element is designed to connect the signal terminal to the reference potential or to disconnect it therefrom via the coupling resistor. That is, the switching element can realize the switching function of the switching unit.The switching element can be designed, for example, as an electrical or electronic switch, in particular as a semiconductor switch. This can have two different switching states for implementing the switching function. The switching states may be an on and off switching state. In the switched-on switching state, the switching element has substantially no electrical resistance. As a result, electrical current can flow essentially unimpeded via the switching element. In the switched-off switching state, on the other hand, the switching element has a substantially infinitely high resistance. A current flow via the switching element can thereby be substantially completely prevented or blocked. The switching element can be designed, for example, as a transistor, for example as a bipolar or field effect transistor, in particular as a MOSFET (metal oxide field effect transistor) or as a thyristor or relay.The coupling resistor is in particular an electrical resistor. This can be connected, for example, in series or series with the switching element between a positive terminal at which the positive potential is present, or a negative terminal at which the negative potential is present, and the signal terminal. In this context, the coupling resistor can be designed, for example, as a pull-up resistor (coupling to the positive potential) or a pull-down resistor (coupling to the negative potential). The dimensioning, i.e. a resistance value of the coupling resistor, can be adapted to the control circuit or to requirements for the PWM communication. A value range for the coupling resistance can be determined, for example, in test tests.In the following embodiments, it will now be described in more detail how the signal type can be detected. This involves recognizing the aforementioned characteristic features, such as the frequency, the duty cycle or the signal level of the control signal.For this purpose, in a further embodiment, it is provided that the activation unit for ascertaining the signal type is designed to evaluate a frequency of the control signal according to a predefined evaluation criterion according to the ascertainment criterion. That is, the signal type is detected based on the frequency at which the signal changes between two defined potentials (e.g., the plus and minus potentials) or levels (high and low). Thus, a direct determination of the signal type can be made without a time delay.In particular in the case of LIN and PWM communication as different communication types, frequency detection delivers particularly clear results, since the drive frequencies of PWM with approximately 50 to 500 Hz and LIN in the medium kilohertz range, for example approximately 19 KHz, are sufficiently far apart.According to the evaluation criterion, the activation unit can determine the frequency, for example, and then compare it with a predefined frequency value range. In this case, such a frequency value range or, for example, a limit value or a limit frequency can be predefined for each signal type. If it is found according to the comparison that the signal frequency lies in one of the value ranges, the signal type associated with the value range is selected as the signal type for the control signal. The assignment of signal type to value range can be implemented in an assignment rule. For example, an allocation table or a so-called look-up table can be used for this purpose.According to a further embodiment, it is provided that the activation unit for determining the signal type is designed to deactivate the switching unit according to the determination criterion and subsequently evaluate a signal level or an (electrical) potential at the signal connection.In this way, it can be determined whether the detected potential or the level at the signal terminal, for example when activating or switching on the device, is in a potential range or level range that is characteristic of the respective signal types. This thus makes use of the fact that, in particular in the case of LIN and PWM, as mentioned at the beginning, different levels are present at the signal connection when the coupling resistor is deactivated. In the LIN communication, the characteristic level is "high", for example. On the other hand, the characteristic level in the PWM communication is, for example, "low" or undefined or floating. This is due to the fact that, without the coupling resistor, the so-called open-X output is present at the signal terminal. That is, the signal terminal is not switched or open from the control device.This type of determination has the advantage that the switching unit and in particular the coupling resistor is deactivated during the detection time. In particular when the communication takes place by means of LIN, this circuitry thus corresponds to LIN-compliant circuitry.For evaluation, the signal level can be compared, for example, with predetermined level values or voltage values which are each assigned to one of the signal types. If, according to the comparison, a match with one of the predetermined voltage values or level values is detected, the associated signal type is selected as the signal type for the control signal. The assignment of the respective signal type to the respective voltage value or level value can be stored, for example, in an assignment rule. The allocation rule can be implemented, for example, in an allocation table or so-called look-up table.In this method, the signal level is preferably first evaluated for the presence of the signal type LIN, i.e. for a LIN signal. If no valid signal type is then detected within a predefined monitoring period, the switching unit can be activated and then, for example, the signal level can be evaluated for a PWM signal. It can thus be ensured that the control circuit is operated in a LIN-compliant manner.The invention also relates to an actuator unit, for example for a motor vehicle, having at least one electronic device as described above and at least one control circuit as described above. The control circuit is designed to control the electronic device and in particular can be connected to it. That is, the control circuit and the device may be functionally linked or connected in the actuator unit.Preferably, a system, such as a motor vehicle with such an actuator unit, can also be provided. The system can also have the aforementioned control device or CPU, which is designed to transmit or transmit the control signal to the actuator unit. The motor vehicle is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.The aforementioned control circuit or the aforementioned actuator unit can of course also be used in a system other than the aforementioned "motor vehicle" system. For example, the control circuit can be used wherever signal transmission or control of electronic devices having different signal types is used, such as a building network or an industrial plant.The invention also relates to a method for operating a control circuit as described above. The method comprises the following steps: First, a respective control signal of a control device connected to the control circuit for controlling the electronically controllable device is detected by means of a signal connection of the control circuit. The respective control signal is then processed by means of a control unit of the control circuit. For this purpose, the control device comprises at least two different signal processing modules which are connected to the common signal connection. For processing, a signal type of the respective control signal is determined by means of an activation unit, as a predefined determination criterion. On the other hand, the activation unit for the processing activates that one of the signal processing modules which is associated with the determined signal type.By means of a switching unit which is comprised by the control circuit and is assigned to one of the at least two signal processing modules, the signal connection is then coupled to a predetermined reference potential in an activated state of the switching unit. By means of the activation unit, the switching unit is subsequently activated or deactivated depending on the determined signal type and depending on the activated signal processing module.Furthermore, the activation unit determines the signal type by alternately activating and deactivating the switching unit cyclically according to the determination criterion and checking the control signal in the activated and deactivated state for an identification feature assigned to the respective signal type.For use cases or application situations which can arise in the method and which are not explicitly described here, provision can be made for an error message and / or a request for inputting a user feedback to be output and / or for a default setting and / or a predetermined initial state to be set according to the method.The invention naturally also includes developments of the method according to the invention and of the actuator unit, which have features as have already been described in connection with the developments of the control circuit according to the invention. For this reason, the corresponding developments of the method according to the invention and of the actuator unit are not described again here.The invention also includes the combinations of the features of the described embodiments. The invention therefore also comprises implementations which each have a combination of the features of a plurality of the described embodiments, provided that the embodiments have not been described as mutually exclusive.Exemplary embodiments of the invention are described below. The following shows: FIG. 1 shows a schematic illustration of an actuator unit having an electronically controllable device which can be operated by means of a control circuit with a control signal of a signal type which can be converted by the device; and FIG. 2 shows a schematic illustration of a method flow diagram for a method for operating the actuator unit according to FIG. 1.The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that are to be considered independently of one another and that also develop the invention independently of one another. Therefore, the disclosure is intended to include combinations of the features of the embodiments other than those illustrated. Furthermore, the described embodiments can also be supplemented by further features of the invention that have already been described.In the figures, identical reference numerals designate functionally identical elements.FIG. 1 shows a schematic illustration of a system 1 comprising an actuator unit 2 and a control device 3. In the present embodiment, the system 1 may implement control of a water pump for an in-vehicle cooling system, for example. In particular, the system 1 can be used for operating the water pump.In this case, the control device 3 can be, for example, a central processing unit (ECU) of the motor vehicle. This means that it can be a superordinate control device in the motor vehicle.The actuator unit 2 according to FIG. 1 comprises, for example, a control circuit 2 aand an electrically controllable device, which is also referred to below as actuator 2 b. The actuator 2 bis configured, for example, as a water pump motor. The water pump engine may be used to realize a circulation of coolant in a cooling circuit of the motor vehicle, for example for engine cooling.In FIG. 1, the actuator unit 2 comprises, for example, only one actuator 2 b. Naturally, more than one actuator, for example two or more actuators, can also be provided. Other examples of an actuator 2 bare a servomotor for a window lifter or for a vehicle seat. The control circuit 2 acan comprise an output connection (not illustrated in FIG. 1 ), by means of which the actuator 2 bis connected to the control circuit.The control device 3 is configured to control the actuator unit 2. The controlling may include, for example, commanding a speed for the engine or diagnosing engine functionality, just to name a few examples herein. The control device 3 and / or the control circuit 2 acan be an electronic circuit, in particular an integrated circuit (IC) or a so-called system-on-a-chip (system-on-a-chip).For control, the control device 3 and the actuator unit 2 can be connected or coupled in an electrical network by means of a communication connection. In the present exemplary embodiment, a physical communication connection, i.e. a wired or wired connection, is illustrated. For this purpose, the control device 3 is connected to a signal terminal 11 of the control circuit 2 aby means of a data line 4. A control signal S for controlling the actuator 2 bmay be transmitted via the signal terminal 11. The communication connection is preferably designed to be bidirectional. That is, the control signal S may be sent from the actuator unit 2 to the control device 3 or vice versa. Thus, the actuator unit 2 can transmit, for example, operating parameters, such as an actual rotational speed or diagnostic data, by means of the control signal S to the control device 3 for evaluation. Conversely, the control device 3 can transmit a control signal S for setting specific operating parameters, such as a setpoint rotational speed, or a specific operating state, such as "on" or "off", for example, to the actuator unit 2. The control signal S can thus code a predetermined control command or a message which the communication partners or subscribers can "understand" or "read".The control circuit 2 ais configured to operate the actuator 2 b. The control circuit 2 ais preferably a driver circuit or a device driver for the actuator 2 b. That is, the control circuit 2 acan convert or translate the control signal S into a setting signal E for the actuator 2 b. The setting signal E can comprise specific settings or values with which the actuator 2 bcan be acted upon in order to implement the respective control command. For example, the setting may be a frequency and / or voltage and / or current and / or other predetermined device setting.It can happen that in an actuator unit 2, as shown in FIG. 1, the actuator 2 bis to be replaced or replaced. In a motor vehicle, this may occur, for example, when a new series of vehicles is being produced or a series of vehicles is to be modernized. However, different actuators 2 bmay be configured for different types of communication. For example, in previous mass-produced vehicles, communication by means of pulse width modulation (PWM) has been set up. In more modern motor vehicles, however, this type of communication is increasingly being replaced by the LIN standard (LIN: Local Interconnect Network). The communication types LIN and PWN are selected here only by way of example. Of course, other types of communication may be used in an analogous manner.LIN and PWM are standards known per se for indicating a signal type and for defining a signal shape for a control signal S. Both use for data transmission, for example, a digital signal format in which the level alternates between two states, namely "high" and "low". In this case, both PWM and LIN can use the high level as a recessive level or reference potential.However, the signal types LIN and PWM differ in the modulation or composition of the signal. In PWM, the control command is encoded via a duty cycle (duty cycle) between high and low levels in a pulse period. In LIN, the control command is encoded according to the LIN protocol, wherein a header and a response are connected in a frame. In addition to the message structure, there are also other characteristic features on the basis of which a LIN signal can be distinguished from a PWM signal. This includes, for example, the switching frequency between high and low levels, which lies between 50-500 Hz in the case of PWM and in the kHz range in the case of LIN.In order for the actuator 2 bto be able to be controlled by means of the control device 3, the control circuit 2 amust be able to recognize the control signal S depending on the respective communication type. That is, the control signal type must conform to the communication type that can be understood or conform to the actuator 2 band / or the control circuit 2 a. In order to avoid that the control circuit 2 aalso has to be replaced when replacing the actuator 2 b, the control circuit 2 is multifunctional, as shown in FIG. 1, i.e. is designed for processing control signals with different signal types. In the present case, the control circuit 2 acan correspondingly process signals of the LIN type and of the PWM type, for example. As a result, the control circuit 2 acan be used universally.For realizing the multifunctionality, the control circuit 2 aaccording to FIG. 1 is configured as follows. The control circuit 2 aincludes an input terminal 10 that forms an interface component for coupling the control device 3. The input connection 10 is designed here as a plug connector, for example, and can be connected to a complementary plug connector of the control device 3 in a plug connection.The input connection 10 comprises in the present case three connection contacts which form physical connection means for the control device 3. A connection contact is assigned to the aforementioned signal connection 11 for transmitting the control signal S. The further two connection contacts are assigned to a positive connection 12 and a negative connection 13.In addition to the terminal contacts, the terminals 11, 12 and 13 comprise, for example, a respective connecting line or signal line. These provide the wiring of the components of the control circuit 2 a, which are designated in more detail below. The internal interconnection of the control circuit 2a is thereby implemented.A positive potential U+ is applied to or tappable from the positive terminal 12. A negative potential U- is applied to or tappable from the negative terminal 13. The negative and positive potentials U-, U+ are predetermined reference potentials in the electrical network, here for example the on-board electrical system of the motor vehicle in which the actuator unit 2 is used. U+ and U- may be provided, for example, by an energy storage device, such as a vehicle battery. The minus potential U- is a ground potential or ground for the network. The water pump control according to FIG. 1 can be used, for example, in an on-board power supply system part with a 12V rated voltage (tappable between U+ and U-), so that U+ can be 12 volts and U-0 volts.U+ and U- may be used as the reference potentials for generating the control signal S. That is, the control signal S that is tappable at the control terminal 11 can be switched back and forth between U+ and U-. For the conversion as a digital signal, this can mean that a signal at the signal terminal 11 is interpreted with a value greater than 7 V as a signal level "High" and with a value less than 7 V as a signal level "Low".For signal processing of the control signal S, the control circuit 2 aincludes a control device 20. The signal connection 11 is coupled to a signal input 24 of the control unit 20. The signal input 24 can be formed, for example, by a pin of the control unit 20.In the present exemplary embodiment, the control device 20 comprises two different signal processing modules. In the present exemplary embodiment, the signal processing modules are a LIN module 22 and a PWM module 23. the LIN module 22 is designed to process control signals according to the LIN standard. The PWM module 23 is configured to process control signals present as PWM signals. Both modules 22, 23 are coupled to the signal connection 11 in particular via the signal input 24. That is, both modules 22, 23 use a common signal line for transmitting the respective control signal S. Between the LIN module 22 and the PWM module 23, the control device 20 can switch over for signal transmission with the control device 3, specifically depending on which signal types the control device 3 specifies.The LIN module 22 can be integrated as a so-called LIN transceiver into a conventional or commercially available control device for PWM signal processing. Such combination control devices are known per se. By switching the LIN module 22 in the control device 20 to the same terminal (here control input 24) as the PWM module 23, a so-called open-X output for the PWM module 23 can form at the signal terminal 11 and thus at the control input 24, wherein X can stand for example for drain or source or collector as terminal contacts for a transistor. This means that the control input 24 is not switched on (independently of any protective switching) when the PWM module is activated "floating"-it remains floating, so that no defined reference potential can be tapped. This can be particularly due to the use of semiconductor switching elements, such as a transistor, which is used, for example, for constructing the control device 3. At the control input 24, an electrical connection to a single, i.e. exclusively to an operating potential, can be established only by means of a corresponding coupling element.In order to enable the PWM communication, therefore, such a coupling element is to be provided. However, this coupling element can be impermissible or undesirable on the basis of specifications for the LIN communication that are internal to the manufacturer or are specified by communication standards.In FIG. 1, the coupling element is therefore implemented by a switching unit 30. The switching unit 30 is associated with the PWM module 23. The switching unit 30 is designed to connect the signal terminal 11 to a predefined reference potential in an activated state. As a result, the reference potential is provided at the signal terminal 11 or the signal input 24. In a deactivated state of the switching unit 30, on the other hand, the connection is disconnected or interrupted; the signal input is in particular "floating". Thus, in order to enable PWM-compliant communication, the switching unit 30 may be placed in the activated state. In order to enable LIN-compliant communication, on the other hand, the switching unit 30 may be placed in the deactivated state.In the present case, the reference potential is, for example, the positive potential U+. The switching unit 30 is thus connected between the signal input 24 and the positive connection 12. In an alternative embodiment, it would be conceivable to use the minus potential U- as the reference potential. The switching unit 30 could then be connected between the signal input 24 and the minus terminal 13.The switching unit 30 includes a coupling resistor 31 and a switching element 32. the coupling resistor 31 and the switching element 32 are connected to each other in series or series connection. In this case, the switching element 32 is connected between the coupling resistor 31 and the positive terminal 12. Alternatively, the coupling resistor 31 and the switching element may be interchanged in their switching order, for example.The coupling resistor 31 is a so-called pull-up resistor in the present exemplary embodiment. The resistor can be dimensioned according to the current requirements for PWM communication. The switching element 32 can implement the switching function, i.e. the connection or disconnection of the positive terminal 12 and the signal terminal 11 or the signal input 24. The switching element 32 is preferably designed as a semiconductor switch, such as a MOSFET. For switching, the switching element 32 can be adjusted or switched between two different switching states, namely "on" or "activated" or "off" or "deactivated". In the switched-on state of the switching element 32, the switching unit 30 is activated. In the switched-off state of the switching element 32, on the other hand, the switching unit 30 is deactivated.The coupling resistor 31 can thus be connected if necessary, i.e. in particular when the PWM communication is required, by means of the switching unit 30. If, on the other hand, the LIN communication is required, the coupling resistor 31 can be switched off.As shown in FIG. 1, the control device 20 also comprises an activation unit 21. On the one hand, the activation unit 21 can determine the signal type of the control signal S according to a predefined determination criterion. This means that the activation unit 21 can determine which signal type, i.e. which communication type the control device 3 uses for the activation. How the determination according to the determination criterion can be implemented is described in more detail later.Furthermore, the activation unit 21 can activate that of the signal processing modules which is associated with the determined signal type. If the signal type LIN is thus detected according to the determination criterion, the LIN module 22 is activated, for example. The PWM module 23 is then deactivated. If, in contrast, the signal type PWM is detected, the PWM module 23 is activated. The LIN module 22 is then deactivated. For activation, the activation unit 21 can provide a corresponding activation signal A to the respective module 22, 23. The respectively active module 22, 23 can then process the control signal S according to the associated signal type in order to determine the setting signal E. That is, the active module can carry out or take over the activation of the actuator 2 b.Finally, depending on the detected signal type and the selected signal processing module, the activation unit 21 can also drive the switching unit 30 for switching between the switched-on and the switched-off state. For this purpose, the activation unit 21 can drive the switching unit 30 with the control signal A. In order to provide the activation signal A to the switching unit 30, the switching unit 30 can be connected, for example, to an enable pin of the control unit 20.The activation of the switching unit 30 takes place in particular only when the associated signal processing module is activated or is to be activated. That is, in the present exemplary embodiment, the switching unit 30 is activated only when the PWM module 23 is also activated or is selected for activation. If, on the other hand, the non-assigned signal processing module, in the present case therefore the LIN module 22, is activated or selected for this purpose, the switching unit 30, on the other hand, is deactivated. The functionality of the control circuit 2 for changing between the different signal processing modes is explained in more detail below with reference to FIG. 2.As shown in FIG. 1, the control circuit 2 acan also comprise an input circuit 40, which is connected, for example, between the signal terminal 11 and the control input 24. The input circuit 40 comprises, for example, components or modules in an electrical circuit, as can be used in a known manner for the signal processing of the control signal S. For example, signal amplification or signal filtering can be carried out by means of the input circuit 40.With reference to FIG. 2, the functionality of the control circuit 2a is now explained once again in detail by way of example. FIG. 2 shows a schematic method flow diagram with individual method steps for a method for operating the control circuit 2 a.In a step S 1, the respective control signal S for the actuator 3 connected to the control circuit 2 ais first transmitted or provided by the control device 3 via the signal connection 11. When the control device 3 is initially connected to the control circuit 2 a, a welcoming signal or coupling signal, for example, can be received or transmitted via the signal connection 11 by means of the control device 3. The control signal S is transmitted, for example, via the input circuit 40 to the signal input 24 of the control unit 20.The control signal S can first be detected by the activation unit 21. In a step S 2 of the method, the activation unit 21 can determine or determine the signal type of the control signal S according to the predefined determination criterion. In this case, the activation unit 21 can evaluate, for example, the characteristic features of the control signal S. According to the determination criterion, for example, an evaluation can be carried out according to the frequency or a duty cycle of the control signal S that is characteristic in the case of PWM communication.Additionally or alternatively, according to the determination criterion for determining the signal type, for example, the activation unit 21 can also initially deactivate the switching unit and then evaluate a signal level at the signal connection 11. That is, when the switching unit 30 is deactivated, the potential at the signal input 24 can be checked. If the level is at "high", the signal type LIN can be deduced in the present exemplary embodiment. If, on the other hand, the signal level is at "low" or if "floating", the signal type PWM can be deduced.A further possibility for signal type detection is that, according to the determination criterion, the switching unit 30 is activated and deactivated alternately in a cyclical manner by means of the activation unit 21, for example. The control signal S is then first checked in the activated state for the possible signal type by comparing the identification features assigned to the signal type with predetermined feature values stored for the respective signal type. This is then repeated in the deactivated state. The cyclical switchover can take place until, for example, a valid communication has been detected.In a step S 3 of the method, the signal processing module assigned to the signal type is next selected by means of the activation unit 21. Thus, for example, if the signal type is LIN, the LIN module 22 is selected and activated. If the signal type is PWM, on the other hand, the PWM module is selected and activated.Thereafter or for example substantially simultaneously, the switching unit 30 is additionally activated or deactivated in a step S 4. In the present exemplary embodiment, the switching unit 30 is to be activated only together with the PWM module 23. If, on the other hand, the LIN module 22 is selected for the signal processing, the switching unit 30 is or remains deactivated.In a step S 5, the control signal S is then processed using the respectively selected signal processing module. This means that the selected module 22, 23 is adopted for the signal processing, i.e. in particular the control or diagnosis of the actuator 2 band is retained in particular. In this case, the control circuit 2 acan determine the settings for the actuator 2 bor record or read current settings of the actuator 2 bto generate diagnostic data.The described method can be carried out, for example, whenever the control device 3 or the actuator unit 2 is activated per se from a switched-off or deactivated state or a sleep mode. Alternatively, the method can also be carried out periodically or repeatedly, for example, in the operating mode or activated mode of the actuator unit 2 after predetermined time intervals. It can thus be ensured that the appropriate communication type for the actuator 2 bis selected for activation at any time.Overall, the exemplary embodiments show how, for a multifunctional control circuit 2 a, both LIN- and PWM-compliant communication with a device to be controlled can be realized.

Claims

Control circuit (2a) for an electronically controllable device (2b) comprising: - a signal connection (11) for detecting a respective control signal (S) from at least one control device (3) connected thereto for controlling the electronically controllable device (2b), - a control device (20) for processing the respective control signal (S), wherein the control device (20) for this purpose comprises at least two different signal processing modules (22, 23) which are connected to the common signal connection (11), - an activation unit (21) on the one hand for determining a signal type of the respective control signal (S) according to a predetermined determination criterion and on the other hand for activating that one of the signal processing modules (22, 23) which is associated with the determined signal type, wherein the control circuit (2a) has a switching unit (30) which is associated with one of the at least two signal processing modules (22, 23), wherein the switching unit (30) is designed to connect the signal terminal (11) to a predetermined reference potential in an activated state, and wherein the activation unit (21) is designed to activate or deactivate the switching unit (30) depending on the determined signal type and depending on the activated signal processing module (22, 23), characterized in that the activation unit (21) for determining the signal type is designed to alternately activate and deactivate the switching unit (30) cyclically according to the determination criterion and to check the control signal (S) in the activated and deactivated state for an identification feature assigned to the respective signal type.Control circuit (2a) according to claim 1, wherein a first of the at least two signal processing modules (22, 23) is configured to process the respective control signal (S) as a PWM signal.Control circuit (2a) according to one of the preceding claims, wherein a second of the at least two signal processing modules (22, 23) is configured to process the respective control signal (S) according to the LIN standard.Control circuit (2a) according to one of the preceding claims 2 or 3, wherein the switching unit (30) is associated with the first signal processing module (23).Control circuit (2a) according to one of the preceding claims, wherein the switching unit (30) comprises a coupling resistor (31) and a switching element (32), wherein the signal terminal (11) is coupled to the reference potential via the coupling resistor (31) and the switching element (32) is configured to connect the signal terminal (11) to the reference potential via the coupling resistor (31).Control circuit (2a) according to one of the preceding claims, wherein the activation unit (21) for determining the signal type is designed to evaluate a frequency of the control signal (S) according to the determination criterion according to a predefined evaluation criterion.Control circuit (2a) according to one of the preceding claims, wherein the activation unit (21) for determining the signal type is designed to deactivate the switching unit (30) and evaluate a signal level at the signal connection (11) according to the determination criterion.Actuator unit for a motor vehicle having at least one electronically controllable device (2b) and a control circuit (2a) according to one of the preceding claims.Method for operating a control circuit (2a) for an electronically controllable device (2b), comprising the following steps: - detecting a respective control signal (S) from at least one control device (3) connected to the control circuit (2a) for controlling the electronically controllable device (2b) by means of a signal connection (11), - processing the respective control signal (S) by means of a control unit (20), wherein the control unit (20) for this purpose comprises at least two different signal processing modules (22, 23) which are connected to the common signal connection (11), and - for the processing: firstly determining a signal type of the respective control signal (S) according to a predetermined determination criterion, and secondly activating that one of the signal processing modules (22, 23) which is associated with the determined signal type by means of an activation unit (21), wherein, by means of a switching unit (30) comprised by the control circuit (2a), which is associated with one of the at least two signal processing modules (22, 23), the signal connection (11) is coupled to a predetermined reference potential in an activated state, and by means of the activation unit (21), the switching unit (30) is activated or deactivated depending on the determined signal type and depending on the activated signal processing module (22, 23), characterized in that the activation unit (21) determines the signal type by alternately activating and deactivating the switching unit (30) cyclically according to the determination criterion and checking the control signal (S) in the activated and deactivated state in each case for an identification feature associated with the respective signal type.

Images