Control assembly

Abstract

Control assembly (100) comprising at least one control unit (ECU) and a voltage-limiting voltage regulator (L, Mlim) which, based on an input voltage (KL30) applied to an input of the control assembly (100), provides a predetermined output voltage range for the control unit (ECU) and at least one further consumer (ES) of the control assembly (100), wherein the control assembly (100) is configured such that, in the event that the control unit (ECU) receives a wake-up signal (WAKE), a first voltage-limiting element (DZlim) enables the control unit (ECU) to start up, and wherein the control assembly (100) further comprises a circuit arrangement designed to - to perform a monitoring (U_Ref CHECK) to check whether a reference voltage (U_Ref) of a specified component of the control unit (ECU) has been reached, and if this is the case, - to provide this reference voltage (U_Ref) to the voltage regulator (L, Mlim) as a reference voltage for regulating its output voltage.

Description

[0001] The present invention relates to a control assembly that is particularly suitable for use in the automotive sector. Part of the control assembly is an improved voltage limiter.

[0002] It is known in the art to provide devices for protection against overvoltages in motor vehicles, such as those that can occur due to the sudden disconnection of inductive loads. Such devices are designed specifically for situations where the electrical connection between a battery undergoing charging and the generator is abruptly interrupted. This scenario is known as a load dump and is particularly critical for sensitive electronic components, such as those used in control units. For example, DE 10 2011 075 115 A1 discloses the selective disconnection of a load in the event of an overvoltage to prevent overloading the voltage limiting circuit.

[0003] The publication DE 10 2015 201 260 A1 shows an overvoltage protection device for a control unit in a vehicle with an electronic control circuit which is inserted between a vehicle electrical system voltage and the control unit and regulates a supply voltage of the control unit to a predetermined value, wherein a protection circuit is connected upstream of the electronic control circuit.

[0004] The publication DE 10 2021 203 501 A1 shows a two-stage circuit for protection against voltage spikes of a CAN transceiver of a vehicle with a control unit which can be in a sleep state and a wake state.

[0005] The publication DE 10 2015 207 783 A1 discloses an electronic control unit for use in an on-board network of a commercial vehicle with an electronic component protected against overvoltage by a protection circuit and with an overvoltage detection unit, wherein the component is designed to operate at a voltage that is lower than the supply voltage in a commercial vehicle.

[0006] The invention is therefore based on the objective of providing an improved voltage limiter for a control assembly.

[0007] This task is solved by the features of independent claims. Advantageous embodiments are the subject of dependent claims.

[0008] A control assembly is proposed, comprising at least one control unit and a voltage-limiting voltage regulator, which, based on an input voltage applied to an input of the control assembly, provides a predetermined output voltage range for a plurality of consumers of the control assembly, wherein the control assembly is configured such that, in the event that the control unit receives a wake-up signal, a first voltage-limiting element enables the control unit to start up, and wherein the control assembly further comprises a circuit arrangement configured to monitor whether a reference voltage of a predetermined component of the control unit has been reached, and if this is the case, to provide this reference voltage to the voltage regulator as a reference voltage for regulating its output voltage.

[0009] In one embodiment, the voltage regulator is configured to remain inactive until it receives a wake-up signal, and the control assembly is configured to allow a power supply to the control unit for startup and operation in the event that the voltage regulator receives a wake-up signal.

[0010] In one embodiment, the circuit arrangement has at least one first transistor which is connected in such a way that, upon detection in the monitoring system that the reference voltage of the specified component of the control unit has been reached, it activates a second transistor and a voltage divider, wherein the second transistor is connected in such a way that it provides the reference voltage emanating from the specified component of the control unit to the voltage regulator for regulating its output voltage, and wherein the voltage divider is connected in such a way that it provides an adjustment of the output voltage of the voltage regulator to the reference voltage.

[0011] In one embodiment, at least one additional transistor is provided, which is electrically connected with its base to the resistor of the voltage divider connected to the output of the voltage regulator and to an anode of a diode.

[0012] In one embodiment, the specified component of the control unit, whose reference voltage is provided to the voltage regulator, is a system base chip of the control unit.

[0013] In one version, the specified output voltage range is between 36 and 40V.

[0014] In one embodiment, the first voltage-limiting element is a Zener diode.

[0015] In one version, a transmission control unit for a vehicle is provided, comprising the control assembly.

[0016] The invention is described below in detail in the following description of exemplary embodiments of the invention, with reference to the figures which show details of the invention, and in the claims. The individual features can be implemented individually or in any combination in a variant of the invention.

[0017] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying figures. Fig. Figure 1 shows a basic structure of a circuit arrangement according to the state of the art. Fig. Figure 2 shows a basic structure of a circuit arrangement according to an embodiment of the present invention. Fig. Figure 3 shows an exemplary comparison of a circuit arrangement according to the prior art and an embodiment of the present invention.

[0018] In the following figure descriptions, identical elements or functions are marked with the same reference symbols.

[0019] A control assembly, preferably for a vehicle, is proposed, which is intended to form a control unit, e.g., a transmission or engine control unit, in particular for forming a mechatronic transmission control unit or an integrated control unit. The control assembly specifically includes a microcontroller for implementing the control functionality. Preferably, the control assembly forms a control unit.

[0020] The control module includes a voltage regulator designed to provide a voltage of a defined level for multiple loads, based on a variable input voltage at an input of the control module, which serves as the control module's supply voltage (e.g., a vehicle battery voltage, designated KL30 in the figures, for terminal 30, i.e., continuous voltage). Such loads, which in this context also include load modules, are referred to as loads and are, in particular, components of the control module and / or external components – e.g., a safety computer, a sensor device, especially one or more power output stages, which are operatively connected to actuators such as valves.

[0021] Preferably, the voltage regulator of the control assembly is designed as a linear voltage regulator. Within the scope of the present invention, the voltage regulator acts as a voltage limiter (also referred to as a limiter) in the event of an overvoltage. The voltage regulator preferably comprises a transistor, in particular a MOSFET Mlim, as well as other components such as further (bipolar) transistors Tlim1, Tlim2, resistors, and capacitors, e.g., for forming filters.

[0022] Within the scope of the present invention, it is further provided that the output voltage, which the voltage regulator continuously supplies to a plurality of loads, can be limited by means of the regulator to a value that is below the value of the maximum permissible input voltage of these loads, particularly in the event of overvoltage. By using the voltage regulator to continuously limit the output voltage, it is advantageously possible to design the control assembly for a lower voltage rating, e.g., 40 V, than would be required by the maximum input voltage in the event of overvoltage, e.g., 58 V. This advantageously enables the use of inexpensive components from the passenger car sector, which are designed, for example, for 40 V, in a commercial vehicle, whose electrical system voltage can be approximately 60 V in the event of a load dump.

[0023] Furthermore, the present invention provides that a predetermined lower voltage limit, e.g. 36V, is not undercut in the event of an overvoltage, so that the MOSFET Mlim of the voltage regulator does not switch to linear operation, which would result in high power dissipation that could damage the voltage regulator and thus restrict the operating voltage range of the loads, in particular the power output stages, since these would have to be switched off to protect the voltage regulator.

[0024] To enable voltage limitation of the input voltage to the load to be supplied to a predetermined lower limit, e.g. 36V, and a predetermined upper limit, e.g. 40V, the method known from the prior art and in Fig. One schematically represented voltage regulator (the voltage limiting circuit) is optimized. The limitation to a predefined voltage range, e.g., 36-40V, is achieved by means of continuous output voltage limiting by the (linear) voltage regulator.

[0025] It is known from the prior art to provide the voltage limiting of the input voltage KL30 (supply voltage via terminal 30) by means of a Zener diode DZref, which is arranged between the output of the transistor Mlim of the voltage regulator L and ground (with further intermediate elements such as reverse polarity protection diode Dref_rp and resistor Rref_pd), as in Fig. 1 schematically and in Fig. 3 shown in detail and with dashed lines. As soon as a wake-up signal WAKE is applied to the control unit ECU of control module 100, the voltage limiting is carried out by the Zener diode DZref (block StdT in Fig. 3, Switch S1 in Fig. 1) This limits the output voltage as soon as the input voltage KL30 exceeds the reference voltage specified by the Zener diode DZref. During the startup process, the limiter MOSFET Mlim may be in linear mode, since the loads are initially off. The input voltage KL30 is always present in unlimited supply voltage at the voltage regulator L and, if applicable, already limited by the voltage regulator at the control unit ECU.

[0026] This arrangement is used according to the invention for the start-up process (Block StartUP in Fig. 3) the control unit ECU continues to be used. However, the previously known circuit (dashed line) is modified. The new circuit arrangement for voltage regulation is shown in Fig. Figure 3 is shown in bold. A Zener diode DZlim is still provided, as shown in Fig. 2 (schematic representation) and Fig. 3 (more detailed explanation) is evident, but only to enable voltage limiting during the ECU startup process. The ECU startup process is also triggered by an external wake signal, which now activates the voltage regulator (switch S1 in Fig. 2 from switch state 1 “Open” to 2 “Closed”). Additionally, a circuit is provided which monitors the reference voltage U_Ref output by the control unit ECU, more precisely by the system base chip contained within it (block U_Ref CHECK in Fig. 3) Once these are started up (3 in Fig. 2, switch S1 is already closed) has reached a stable predetermined value (4 in Fig. 2), this is fed to input E of the control loop of the voltage regulator L as a setpoint for comparison with the actual value of the voltage regulator L (switch S2 in Fig. 2 switches from switch position 3 to 4). Treg is activated via Tref (switch S2 switches from diode DZlim to U_Ref, i.e., from switch position 3 to 4), which feeds U_Ref to input E of the control loop (setpoint). Simultaneously, the actual value of output A of the voltage regulator, i.e., the output voltage of voltage regulator L, is adjusted to the target value via a voltage divider Rref1 / Rref2 and also supplied to input E of the control loop (comparison of setpoint and actual value). If the output voltage of the voltage regulator, adjusted to U_Ref, is greater than the reference voltage U_Ref, the output voltage of voltage regulator L is limited according to the equation: V.kl30_lim=V.U1_QVR+(V.Tlim2_BE+V.Treg_CE_sat)*(1+Rref1 / Rref2)*Rref2)−(V.Dref_rp_F+V.Tref_CE_sat)*Rref1 / Rref2

[0027] Here, V.U1_QVR+(V. Tlim2_BE+V.Treg_CE_sat) is the portion of the reference voltage path (setpoint) including the addition of V.U1_QVR via the collector-emitter junction of Treg to the emitter of Tlim2. The path of the reference voltage (setpoint) is: Rlim2_b, base-emitter junction of Tlim2, collector-emitter junction of Treg, U_Ref.

[0028] Furthermore, (1+Rref1 / Rref2)*Rref2)-(V.Dref_rp_F+V.Tref_CE_sat)*Rref1 / Rref2 is the portion of the feedback path (actual value) including the addition of Dref_rep and Rref2 via the collector-emitter junction of Tref to ground. This results in the regulator's output voltage being adjusted to U_Ref. The feedback path (actual value adjusted to U_Ref) is: output voltage regulator, Rref1, Dref_rp, Rref2, collector-emitter junction of Tref. Where: V.kl30_lim: limited voltage at the output of the voltage regulator V.U1_QVR = U_Ref, V.Tlim2_BE: Base-emitter voltage applied to transistor Tlim2 V.Treg_CE_sat: Collector-emitter voltage (saturation) applied to transistor Treg V.Dref_rp_F: forward voltage applied to diode Dref_rp V.Tref_CE_sat: Collector-emitter voltage (saturation) applied to transistor Tref

[0029] The circuit arrangement is described in essential details in Fig. Figure 3 is shown in bold. Essentially, two transistors are used to monitor the reference voltage U_Ref of the system base chip and switch it on once it is reached. Tref and Treg work together to switch the reference voltage on. The applied reference voltage U_Ref and the Zener diode DZlim are connected to the same node, the emitter of Tlim2. The reference voltage is lower than the Zener voltage at the node and thus defines the voltage. Switching on the reference voltage U_Ref simultaneously activates the voltage divider R1 / R2 via block U_Ref CHECK. This replaces the monitoring by the Zener diode DZref (block StdT). As with any circuit, other components such as resistors, capacitors, and possibly diodes are used, depending on the precise circuit design (which is determined in detail by a qualified technician).The use of the reference voltage U_Ref of the system base chip is advantageous because it provides increased precision in the output voltage accuracy of the voltage limiting during normal operation, and thus better utilization of the battery voltage range in which operation of the power output stages ES is possible.

[0030] Furthermore, voltage regulators L are currently always active, meaning that the loads (consumers) at their outputs are always supplied with energy. These loads include, for example, parts of the ECU such as the system base chip or one or more microcontrollers, or one or more power output stages ES. In particular, the drivers of the power output stages increase the quiescent current, but to a lesser extent, so do the power switches themselves and the capacitors of the intermediate circuit. This leads to an increased load on the vehicle battery due to leakage and quiescent currents of the downstream components, up to the point of exceeding the permissible quiescent current specification of the ECU. For this reason, according to the invention, the voltage regulator L is only switched on after it has received a wake-up signal, as shown in Fig. 2 and Fig. As indicated in section 3, the control unit ECU also receives a wake-up signal, as in the prior art. However, since the voltage regulator L is connected between the control unit ECU and the supply voltage KL30, the control unit ECU can only be supplied with energy when the voltage regulator L becomes active. This also means that the control unit ECU is not supplied with energy as long as no wake signal is present; that is, only after the voltage regulator L has been activated by the external signals does the control unit ECU start up by supplying the necessary components from the output of the voltage regulator L. This also minimizes leakage / quiescent currents and thus the load on the vehicle battery.

[0031] In one embodiment, the base-emitter voltage of transistor Tlim2 is compensated by a forward voltage of a diode Dref_rp arranged between its base and emitter.

[0032] Thus, temperature-dependent component tolerances in the reference voltage path (target value) are largely compensated for by adjustments in the feedback path (actual value). At the same time, Dref_rp ensures that the transistor Tref is not damaged in the event of reverse polarity (LV battery incorrectly connected, RP = Reverse Polarity), as no current flows (the diode is reverse-biased in the case of reverse polarity).

[0033] The in Fig. The transistor Tlim2 shown in the diagram is electrically connected with its collector to the base of another transistor Tlim1 via a resistor, with its emitter to the cathode of Zener diode DZlim, as well as to the emitter of Treg (Treg as switch S2 for the electrical connection of U_Ref at the emitter of Tlim2 via the collector-emitter path of Treg), and with its base via Rlim2b to the resistor Rref1 of the voltage divider Rref1 / Rref2, which is connected to the output of the voltage regulator L, as well as to the anode of Dref_rp.

[0034] The input signal is the control deviation between the output voltage (actual value) and the setpoint, as previously described. The two (bipolar) transistors Tlim2 and Tlim1 apply this control deviation to the limiter MOSFET Mlim, resulting in a reduction of the gate-source voltage of Mlim and linear operation of the MOSFET Mlim. The greater the control deviation (i.e., the higher the output voltage compared to the setpoint), the more base current is available for Tlim2. This leads to a higher collector current for Tlim2 and consequently a higher base current for Tlim1. This, in turn, results in a higher collector current for Tlim1, which reduces the gate-source voltage at the limiter MOSFET Mlim. Thus, the limiter MOSFET Mlim operates linearly, resulting in a larger voltage drop across the drain-source path and a lower output voltage.

[0035] The proposed new circuit arrangement and the resulting more precise reference voltage U_Ref of the voltage regulator L enable the operation of power output stages ES in an extended battery voltage range of, for example, 36V, while simultaneously limiting the voltage of the components downstream of the voltage regulator L (the limiter circuit) to, for example, a maximum of 40V. This allows components from the passenger car sector to be used in commercial vehicles as well, leading to significant savings in development time and costs. Furthermore, increased component availability is achieved, as the power consumption of individual components is no longer relevant, and additional switches for isolating these components can be eliminated. Reference symbol list 100 Control assembly KL30 Input voltage WAKE Alarm U_Ref CHECK verification circuit Startup connection limiter U_Ref Reference voltage ECU control unit ES power output stage L voltage regulator A output of L E Entrance from L Mlim Transistor DZref, DZlim Zener diode Dreg, Dref_rp Diode Treg Transistor Tref, Tlim1, Tlim2 Transistor Rref1 / Rref2 voltage divider

Claims

[1] Control assembly (100) comprising at least one control unit (ECU) and a voltage-limiting voltage regulator (L, Mlim) which, based on an input voltage (KL30) applied to an input of the control assembly (100), provides a predetermined output voltage range for the control unit (ECU) and at least one further consumer (ES) of the control assembly (100), wherein the control assembly (100) is configured such that, in the event that the control unit (ECU) receives a wake-up signal (WAKE), a first voltage-limiting element (DZlim) enables the control unit (ECU) to start up, and wherein the control assembly (100) further comprises a circuit arrangement designed to - to perform a monitoring (U_Ref CHECK) to check whether a reference voltage (U_Ref) of a specified component of the control unit (ECU) has been reached, and if this is the case, - to provide this reference voltage (U_Ref) to the voltage regulator (L, Mlim) as a reference voltage for regulating its output voltage. [2] Control assembly (100) according to claim 1, wherein the voltage regulator (L, Mlim) is configured to remain inactive until it receives the wake-up signal (WAKE), and wherein the control assembly (100) is configured to allow, in the event that the voltage regulator (L, Mlim) receives the wake-up signal (WAKE), a power supply to the control unit (ECU) for startup and operation. [3] Control assembly (100) according to claim 1 or 2, wherein the circuit arrangement has at least one first transistor (Tref) which is connected such that, upon detection in the monitoring (U_Ref CHECK) that the reference voltage (U_Ref) of the predetermined component of the control unit (ECU) has been reached, it activates a second transistor (Treg) and a voltage divider (Rref1, Rref2), wherein the second transistor (Treg) is connected such that it provides the reference voltage (U_Ref) emanating from the predetermined component of the control unit (ECU) to the voltage regulator (L, Mlim) for regulating its output voltage, and wherein the voltage divider (Rref1, Rref2) is connected such that it provides an adjustment of the output voltage of the voltage regulator (L, Mlim) to the reference voltage (U_Ref). [4] Control assembly (100) according to claim 3, wherein at least one further transistor (Tlim2) is provided which is electrically connected with its base to the resistor (Rref1) of the voltage divider (Rref1, Rref2) connected to an output (A) of the voltage regulator (L, Mlim) and to an anode of a diode (Dref_rp). [5] Control assembly (100) according to one of the preceding claims, wherein the specified component of the control unit (ECU) whose reference voltage (U_Ref) is provided to the voltage regulator (L, Mlim) is a system base chip of the control unit (ECU). [6] Control assembly (100) according to one of the preceding claims, wherein the specified output voltage range is between 36 and 40V. [7] Control assembly (100) according to one of the preceding claims, wherein the first voltage limiting element (DZlim) is a Zener diode. [8] Transmission control for a vehicle, comprising a control assembly (100) according to any of the preceding claims.

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