Shutdown module for the safe disconnection of a DC load

Abstract

The invention relates to a shutdown module designed for the safe disconnection of a DC load, comprising a shutdown unit (1) with semiconductor-based switching elements, a control unit (2), a power supply unit (4), and a diagnostic unit (3) for monitoring the switching state of the semiconductor-based switching elements. The shutdown module is particularly suitable for the safe disconnection of the power supply to laser beam sources.

Description

The invention relates to a disconnection module provided for safe disconnection of a DC voltage load, which module comprises semiconductor-based switching elements for disconnection of the DC voltage load and a diagnostic unit for monitoring the switching state of the semiconductor-based switching elements. The switch-off module is suitable in particular for reliably switching off the voltage supply of laser beam sources.In order to avoid risks during the operation of laser systems, these are regularly monitored with a series of sensors or are provided with various safety switches. To ensure safety of the system, the laser system is switched off when a switching signal triggered by the sensors or the safety switches is triggered, in that the voltage supply to the laser beam source is interrupted. In order to bring about a reliable, i.e. comprehensible or diagnostic, interruption of the voltage supply, relays with positively guided contacts are usually used as switching elements for switching off the electrical loads. By means of the forced guidance of the contacts, it is possible to predict whether the load contacts are open. A diagnostic coverage of 90%-99% is achieved. The diagnosis of the switching state of the switching elements makes it possible to monitor the functionality of the shutdown device and thus to perform a safe shutdown. Disadvantages of conventional relay technology, however, are the wear-related limited service life (to approximately 50,000 switching cycles) and the relatively large installation space requirement.The basically possible replacement of mechanically contacting relays by semiconductor components requires alternative monitoring elements because of the lack of a diagnostic possibility at the load contacts in order to diagnose the load disconnection with semiconductor-based switching elements in an equivalent manner as in mechanically contacting relays and thus ultimately to perform a safe load disconnection.DE 10 2019 129 158 A1 discloses a circuit arrangement which replaces mechanically contacting relays by semiconductor relays, so-called solid state relays (abbreviated to SSR), wherein the switching state of the semiconductor relays is monitored by means of a circuit arrangement by detecting, comparing the voltage potential before and after each semiconductor relay and generating a control signal on the basis of this potential comparison. The semiconductor relays are used to interrupt the direct current supply of a laser driver supplied with a direct current voltage of 24 V or 48 V.DE 10 2006 030 448 A1 discloses an output circuit for an output module for switching at least one connected load, wherein the output circuit is characterized by a single-channel peripheral terminal for connecting the at least one load, and comprises at least two driver modules, in particular FET transistors, connected in series between a supply voltage and the peripheral terminal, wherein each of the driver modules is connected via a separate control channel to a logic for driving the driver modules assigned to the output module. The output circuit may comprise two semiconductor-based switch-off circuits driven separately via optocouplers and a feedback signal.Chang, C.; Chen, T.: Why Pre-charge Circuits are Necesary in High-Voltage Systems. Application Letter - Texas Instruments, 2021. URL:https: / / www.ti.com / document-viewer / lit / html / slvafb0 discusses the need for precharge on high voltage circuits. Without a pre-charge circuit, welds can occur when the contactor closes and a short arc can result. A precharge circuit may be used to prevent stress and damage to the electrical system by implementing a resistor and a switch for limiting inrush current.It is an object of the invention to provide a shutdown module for safe shutdown of electrical loads, with the DC voltage loads of max. 120 V and 100 A can be safely switched off by a circuit based on semiconductor components. A diagnostic coverage of 90%-99% is to be achieved.This object is achieved by a shutdown module having the features according to claim 1. Practical further developments of the invention are set out in claims 2 to 10.According to the invention, the disconnection module serves for the safe disconnection of a DC voltage load which is present in the form of a load voltage as an incoming input load voltage between an input load potential and a load-side ground potential and as an outgoing output load voltage between an output load potential and the load-side ground potential at a load circuit of the disconnection module. The switch-off module is configured, in the event of interruption of at least one switching signal present at the switch-off module, to switch off the load circuit by means of a semiconductor-based switch-off unit (i.e. a switch-off unit having semiconductor components as switching elements) by interrupting the connection of input load potential and output load potential, and to output at least one feedback signal identifying the load switch-off.According to the invention, the disconnection module has the semiconductor-based disconnection unit incorporated in the load circuit, a drive unit at which the switching signal or signals are received, a diagnostic unit at which the feedback signal or signals originate, and a voltage supply unit connected to a supply voltage for supplying voltage to the units of the disconnection module. All electronic switch elements or components of the switch-off module are semiconductor components, i.e. no mechanically contacting relays or contactors are integrated in the switch-off module.The shutdown unit comprises a first and a second shutdown circuit and a charging circuit. The switch-off unit is incorporated in the load circuit of the switch-off module in such a way that the connection between the input load potential and the output load potential comprises a main connection connected via the two switch-off circuits and a secondary connection connected in parallel via the charging circuit.The first and the second shutdown circuit each have a semiconductor circuit, i.e. a circuit based on semiconductor switches, having at least one semiconductor switch. The respective semiconductor switch is preferably a metal oxide semiconductor field effect transistor (abbreviated to MOSFET). Metal oxide semiconductor field effect transistors are known electronic semiconductor components of electronic circuits. The metal-oxide-semiconductor field-effect transistor or transistors are referred to below as the established MOSFET (abbreviated for: metal-oxide-semiconductor field-effect transistor). Furthermore, bipolar transistors, for example insulated gate bipolar transistors (absk, can also be used as semiconductor switches. IGBTs, or Insulated-Gate Bipolar Transistors). In principle, all similarly acting semiconductor components, i.e. in particular transistor components, can be used as semiconductor switches.The main connection between the input load potential and the output load potential is formed by the series-connected semiconductor circuits of the first cut-off circuit and the second cut-off circuit. Each of the semiconductor circuits of the first turn-off circuit and of the second turn-off circuit preferably has in each case a plurality of parallel-connected semiconductor switches, in particular in each case two, three or four parallel-connected semiconductor switches (for example MOSFETs). The parallel connection takes place for improved load distribution and thus for better distribution of the thermal stress. In the main connection between the semiconductor circuit of the first turn-off circuit and the semiconductor circuit of the second turn-off circuit, an interposer potential is present.The charging circuit comprises at least one semiconductor switch and at least one power resistor, which, connected in series, form the shunt connection between the input load potential and the output load potential. A charging voltage potential is present in the shunt connection between the at least one semiconductor switch and the power resistor or resistors of the charging circuit.The drive unit has a drive input circuit, a first switch-off control for driving the first switch-off unit, a second switch-off control for driving the second switch-off unit, and a charging circuit drive for driving the charging circuit. According to the invention, the switching signal or signals are input at the drive input circuit in the form of a first and a second switching signal, i.e. the drive unit or the drive input circuit has the corresponding inputs. The drive input circuit is furthermore configured to process the switching signals.The semiconductor switch or switches of the semiconductor circuit of the first and second turn-off circuits are connected to the respectively assigned turn-off controller via a respective optocoupler for controlling the activation or blocking of the main connection, i.e. the first turn-off controller is connected to the first turn-off controller and the second turn-off controller is connected to the second turn-off controller.The first switch-off control and the second switch-off control are configured to activate the main connection if both switching signals arriving at the drive unit are present and the voltage difference between the input load potential and the output load potential falls below a predefined threshold value. The semiconductor circuit of the first switch-off circuit is activated when the first switching signal is present or active and the voltage difference between the input load potential and the output load potential falls below the predefined threshold value; the semiconductor circuit of the second switch-off circuit is activated when the second switching signal is present or active and the voltage difference between the input load potential and the output load potential falls below the predefined threshold value. The main connection is consequently only active if the series-connected semiconductor circuits of the first and the second turn-off control are simultaneously active.Furthermore, the semiconductor switch of the charging circuit for controlling the activation or blocking of the secondary connection is connected to the charging circuit drive via an optocoupler.The charging circuit control is configured to activate the secondary connection by controlling the optocoupler of the charging circuit when both switching signals arriving at the control unit are present, i.e. when both switching signals are active.According to the invention, the feedback signal or signals are emitted as a first and a second feedback signal from the diagnostic unit, i.e. the diagnostic unit has corresponding outputs. For this purpose, the diagnostic unit comprises a first diagnostic channel for outputting the first feedback signal and a second diagnostic channel for outputting the second feedback signal.The first diagnostic channel is configured to signal proper disconnection of the load circuit via the first feedback signal whenthe voltage difference between the charging voltage potential and the output load potential exceeds a predetermined threshold value, andthe voltage difference between the input load potential and the interposer potential exceeds a predetermined threshold value, andthe voltage difference between the output load potential and the load-side ground potential falls below a predetermined threshold value.The second diagnostic channel is configured to signal proper disconnection of the load circuit via the second feedback signal whenthe voltage difference between the charging voltage potential and the output load potential exceeds a predetermined threshold value, andthe voltage difference between the interposer potential and the output load potential exceeds a predetermined threshold value, andthe voltage difference between the output load potential and the load-side ground potential falls below a predetermined threshold value.The shutdown module according to the invention makes possible the load circuit without the use of mechanically contacting relays by using the semiconductor switches in the semiconductor circuits of the first and second shutdown circuits. The semiconductor-based circuits and switching elements of the switch-off module require significantly less installation space than mechanically contacting relays; they also allow a significantly higher number of switching cycles.The charging circuit integrated into the switch-off unit pre-charges the load circuit in the case of switch-on; as a result, the loading of the semiconductor switches of the two switch-off circuits in the case of switch-on is restricted, i.e. switch-on overloads of the semiconductor switches in the switch-off circuits are avoided.The combined diagnostic unit signals the proper shutdown of the DC voltage load by carrying out a functional diagnosis of the various structural units of the shutdown module; the information generated in this case is linked and output in the form of the two feedback signals. As a result, by means of the disconnection module according to the invention, which carries out the disconnection of the DC voltage load by its semiconductor components, i.e. the semiconductor switches, in the disconnection unit, a degree of diagnostic coverage of 90%-99% is achieved, i.e. a degree of diagnostic coverage which corresponds to the established contact relay circuits.According to one configuration, the switch-off unit of the switch-off module according to the invention also has a first discharge circuit and a second discharge circuit; in addition, the drive unit has a first discharge circuit drive for driving the first discharge circuit and a second discharge circuit drive for driving the second discharge circuit.The first discharge circuit comprises at least one semiconductor switch and at least one power resistor which, connected in series, form a first discharge connection between the output load potential and the load-side ground potential, wherein the semiconductor switch of the first discharge circuit is connected to the first discharge circuit drive via an optocoupler in order to control the activation or blocking of the first discharge connection. The first discharge circuit drive is configured to activate the first discharge connection by driving the optocoupler of the first discharge circuit when the first switching signal arriving at the drive unit is interrupted, i.e. inactive.The second discharge circuit is constructed in a comparable manner to the first discharge circuit, i.e. the second discharge circuit comprises at least one semiconductor switch and at least one power resistor which, connected in series, form a second discharge connection, connected in parallel with the first discharge connection, between the output load potential and the load-side ground potential, wherein the semiconductor switch of the second discharge circuit is connected to the second discharge circuit drive via an optocoupler in order to control the activation or blocking of the second discharge connection. The second discharge circuit drive is configured to activate the second discharge connection by driving the optocoupler of the second discharge circuit when the second switching signal arriving at the drive unit is interrupted, i.e. inactive.The discharge circuits are activated after the switch-off circuits have been switched off. In the event of a fault, the discharge circuits limit the output load voltage by discharging current via the discharge circuits. The sizes of the power resistances in the first discharge circuit and in the second discharge circuit are preferably dimensioned such that the activated discharge connections reduce the output load voltage to one third of the input load voltage. This is achieved, for example, by the power resistors in the first discharge circuit and in the second discharge circuit together having a resistance value half as low as the power resistors in the charge circuit. If laser diodes are connected to the output load voltage, it is possible, by reducing the output load voltage to a level sufficiently low compared to the input load voltage, to ensure that the laser diodes no longer emit radiation. If the output load voltage is reduced to one third of the input load voltage, this is regularly the case.It can furthermore be provided that the shutdown unit has a failure protection circuit with a failure discharge connection between the output load potential and the load-side ground potential, wherein the failure discharge connection has at least one power resistor or two power resistors connected in parallel. This additional discharge resistor or resistors discharges the load circuit in the event of a voltage failure of the supply voltage of the voltage supply unit.According to a further configuration of the shutdown module, the activation unit further has an overload protection circuit connected to the second shutdown activation, which circuit is configured to deactivate the second shutdown activation if the supply voltage of the voltage supply unit falls below a predefined threshold value. As a result, the switch-off circuits are protected in the event of weakening of the supply voltage.The voltage supply unit preferably has a first voltage converter for converting the supply voltage into a control voltage, which in particular serves for supplying voltage to the drive unit and the diagnostic unit, and further voltage converters for converting the supply voltage into floating semiconductor switch control voltages. The semiconductor switch control voltages serve to control the semiconductor switches in the two cut-off circuits, in the charging circuit and in the two discharging circuits. Preferably, three or four further voltage converters for converting the supply voltage into three or four floating semiconductor switch control voltages are provided within the voltage supply unit. All the voltages mentioned are direct voltages. Preferably, the supply voltage is a 24 V DC voltage, the control voltage is a 5 V DC voltage, and the semiconductor switch control voltages are each a 12 V DC voltage.Furthermore, a temperature monitoring circuit for temperature monitoring of the switch-off module can be integrated into the voltage supply unit, wherein the temperature monitoring circuit is connected to the first voltage converter, for example. For this purpose, the first voltage converter has a control input which is connected to the temperature overflow circuit. The first voltage converter receives a signal via the control input in the event of temperature overload and switches off the voltage converter; the switch-off module is then deactivated as a result. The temperature monitoring circuit preferably comprises or consists of two or three parallel-connected circuits, each of these two circuits having a thermistor for temperature detection. The temperature monitoring circuit is preferably designed such that the shutdown takes place when a shutdown temperature of 80° C. is reached or when it is exceeded.The voltage supply unit preferably also has an input filter for filtering electromagnetic interference from the supply voltage present.According to one configuration of the switch-off module, the charging circuit has two semiconductor switches, i.e. a first charging circuit semiconductor switch and a second charging circuit semiconductor switch, and at least one power resistor, wherein the first charging circuit semiconductor switch, the second charging circuit semiconductor switch and the power resistor, connected in series, form the shunt connection between the input load potential and the output load potential. A first charging voltage potential is present in the shunt connection between the first charging circuit semiconductor switch and the power resistor or resistors of the charging circuit, and a second charging voltage potential is present between the first and the second charging circuit semiconductor switch.When using the above-described configuration of the charging circuit comprising two semiconductor switches, the diagnostic unit has a modified control of the diagnostic channels:When using the charging circuit with two semiconductor switches, the first diagnostic channel is configured to signal proper disconnection of the load circuit via the first feedback signal ifthe voltage difference between the first charging voltage potential and the second charging voltage potential exceeds a predetermined threshold value, andthe voltage difference between the input load potential and the interposer potential exceeds a predetermined threshold value, andthe voltage difference between the output load potential and the load-side ground potential falls below a predetermined threshold value.Furthermore, when using the charging circuit with two semiconductor switches, the second diagnostic channel is configured to signal proper disconnection of the load circuit via the second feedback signal ifthe voltage difference between the second charging voltage potential and the output load potential exceeds a predetermined threshold value, andthe voltage difference between the interposer potential and the output load potential exceeds a predetermined threshold value, andthe voltage difference between the output load potential and the load-side ground potential falls below a predetermined threshold value.The predetermined threshold values of the voltage differences are each set to a value in the range from 0.5 V to 16 V, in particular to 4 V±1 V, 8 V±1 V or 14 V±1 V. This is realized by the construction of the circuits, the selection of the electronic components and their setting or programming.The invention is explained in more detail below on the basis of exemplary embodiments and with reference to the schematic drawings, wherein identical or similar features are provided with the same reference numerals; in this regard, FIG. 1 : a first embodiment of the shutdown module in a block diagram representation; FIG. 2 : shows the circuit diagram of the shutdown unit of the first embodiment of the shutdown module with details concerning the shutdowns; FIG. 3 : shows the circuit diagram of the shutdown unit of the first embodiment of the shutdown module with details concerning the charging circuit and the first discharging circuit; FIG. 4 : shows the circuit diagram of the shutdown unit of the first embodiment of the shutdown module with details concerning the charging circuit and the second discharging circuit; FIG. 5 is a circuit diagram of the driving input circuit; FIG. 6 : the circuit diagrams of the switch-off triggerings; FIG. 7 is a circuit diagram showing the charging circuit and discharging circuit drivers; FIG. 8 : shows the circuit diagrams of the voltage supply unit of the first embodiment of the switch-off module with details of the first voltage converter generating the control voltage and for temperature monitoring; FIG. 9 : shows the circuit diagrams of the voltage supply unit of the first embodiment of the switch-off module with details of the voltage converters which generate the floating semiconductor switch control voltages; FIG. 10 : shows the circuit diagram of the first diagnostic channel of the diagnostic unit of the first embodiment of the switch-off module; FIG. 11 : shows the circuit diagram of the second diagnostic channel of the diagnostic unit of the first embodiment of the switch-off module; FIG. 12 shows a second embodiment of the shutdown module in a block diagram representation; FIG. 13 : shows the circuit diagram of the shutdown unit of the second embodiment of the shutdown module with details concerning the charging circuit and the first discharging circuit; FIG. 14 : shows the circuit diagrams of the voltage supply unit of the second embodiment of the switch-off module with details of the first voltage converter generating the control voltage and for temperature monitoring; FIG. 15 : shows the circuit diagrams of the voltage supply unit of the first embodiment of the switch-off module with details of the voltage converters which generate the floating semiconductor switch control voltages; FIG. 16 : shows the circuit diagram of the first diagnostic channel of the diagnostic unit of the second embodiment of the shutdown module; and FIG. 17 : shows the circuit diagram of the second diagnostic channel of the diagnostic unit of the second embodiment of the shutdown module.In the following circuit diagrams and circuit diagrams, the individual components are represented with the established circuit signs and are denoted with the usual abbreviations, i.e.: C for capacitors, D for diodes, DCDC for (direct current) voltage converters, IC for an integrated circuit (for example a logic component), L for coils, M for metal oxide semiconductor field effect transistors (MOSFETs), NTC for thermistor thermistors, Q for transistors and R for resistors. The numbering following the abbreviations in each case serves for distinguishing and accurately identifying the respective component in the circuit diagram. The terminals of the load voltage are denoted by the abbreviation K and all further terminals by the abbreviation X.FIGS. 1 to 11 show a first embodiment of the shutdown module and FIGS. 12 to 17 show a second embodiment of the shutdown module, the second embodiment largely corresponding to the first embodiment. With regard to the second embodiment of the shutdown mode, only its particularities are explained in more detail in this respect; for details which are not described, reference is made to the description of the first embodiment of the shutdown module.FIG. 1 shows the individual modules of the shutdown module of the first embodiment, namely the shutdown unit 1, the control unit 2, the diagnostic unit 3 and the voltage supply unit 4 including their respective subordinate functional units.The DC voltage load is present at the switch-off module in the form of the input load voltage 10 and is tapped at the switch-off module in the form of the output load voltage 11. The input load voltage 10 is connected via the connection terminals K1 and K2, wherein the input load potential VIN is present at the connection terminal K1 and the load-side ground potential GNDP is present at the connection terminal K2. The connection terminals K 3 and K 4 form the connection of the output load voltage 11, wherein the output load potential VOUTis present at the connection terminal K 3 and the load-side ground potential GNDP is present at the connection terminal K 4.The switching signals 12 enter the control unit 2, wherein the first switching signal 12.1 is present via the terminal X1 and the second switching signal 12.2 is present via the terminal X2 at the control input circuit 2.6 of the control unit 2. In the control input circuit 2.6, the first switching signal 12.1 is processed to form the first switching signal potential INT1 and the second switching signal 12.2 is processed to form the second switching signal potential INT2. The first switching signal potential INT1 and the second switching signal potential INT2 enter the first switch-off control 2.1, the second switch-off control 2.2, the charging circuit control 2.3 as well as the first discharging circuit control 2.4 and the second discharging circuit control 2.5 as control variables.The first shutdown driver 2.1 processes the first switching signal potential INT1, as well as the input load potential VIN and the output load potential VOUT to generate the first switching control potential DR-SW1. Similarly, the second shutdown driver 2.2 processes the second switching signal potential INT2, as well as the input load potential VIN and the output load potential VOUT to generate the second switching control potential DR-SW2. The first switching control potential DR-SW1 serves to drive the first cut-off circuit 1.1; the second switching control potential DR-SW2 serves accordingly to drive the second cut-off circuit 1.2. The interposer potential VSW12 is tapped between the two cut-off circuits 1.1, 1.2.The charging circuit driver 2.3 processes the first switching signal potential INT1 and the second switching signal potential INT2 to generate the charging driver potential DR-CRG. The charging circuit 1.3 is driven via the charging drive potential DR-CRG. The charging voltage potential VCRG is tapped at the charging circuit 1.3.By means of the first discharge circuit control 2.4, the first discharge control potential DR-DSC1 is generated by processing the first switching signal potential INT1, and by means of the second discharge circuit control 2.5, the second discharge control potential DR-DSC2 is generated by processing the second switching signal potential INT2. The first discharge control potential DR-DSC1 serves to control the first discharge circuit 1.4; the second discharge control potential DR-DSC2 serves accordingly to control the second discharge circuit 1.5.The power supply of the switch-off module is effected by means of the power supply unit 4, at which the supply voltage 13 is present via the connections X3.1, X3.2. The supply voltage 13 at the level of 24 V, characterized by the supply voltage potential V 24P, which is filtered via an input filter, is converted via a first voltage converter connected to the temperature monitoring circuit T into a 5 V control voltage, characterized by the control voltage potential V 5P, and via further voltage converters into the 12 V semiconductor switch control voltages, characterized by the first semiconductor switch control potential V 12P-S 1, the second semiconductor switch control potential V 12P-OUT and the third semiconductor switch control potential V 12P-D.The 5 V control voltage is used in particular for supplying voltage to the drive unit 2 and the diagnostic unit 3; the 12 V semiconductor switch control voltages are used for switching the semiconductor switches (here MOSFETs) in the first shutdown circuit 1.1, in the second shutdown circuit 1.2, in the charging circuit 1.3 and in the first discharge circuit 1.4 and in the second discharge circuit 1.5.The diagnostic unit 3 outputs the feedback signals 14, wherein the first feedback signal 14.1 generated by the first diagnostic channel 3.1 can be tapped off at the connections X3.3, X3.4 and the second feedback signal 14.2 generated by the second diagnostic channel 3.2 can be tapped off at the connections X3.5, X3.6.The charging voltage potential VCRG, the output load potential VOUT, the input load potential VIN, the interposer potential VSW12 and the load-side ground potential GBP are used as input signals for generating the first feedback signal 14.1 by means of the first diagnostic channel 13.1; the charging voltage potential VCRG, the output load potential VOUT, the interposer potential VSW12 and the load-side ground potential GBP are used as input signals for generating the second feedback signal 14.2.According to the circuit diagram of the switch-off unit 1 shown in FIG. 2, the two switch-off circuits 1.1, 1.2 each have a semiconductor circuit comprising three parallel-connected N-channel MOSFETs as semiconductor switches. In the first shutdown 1.1, the three MOSFETs are denoted by M 1, M 2 and M 3 and in the second shutdown 1.2 by M 4, M 5 and M 6. Both semiconductor circuits are connected in series and form the main connection between the input load potential VIN and the output load potential VOUT, wherein the interposer potential VSW12 is tapped between the two semiconductor circuits. The semiconductor switches (MOSFETs) are driven via the optocouplers designated IC 1 and IC 2, wherein the first switching control potential DR-SW 1 is present as an input signal at optocoupler IC 1 and the second switching control potential DR-SW 2 is present as an input signal at optocoupler IC 2. The resistors R 1, R 2, R 3, R 4, R 5 and R 6 serve as gate series resistors; the resistors R 101 and R 102 ensure reliable switching off of the semiconductor switches (MOSFETs) in the event of a failure of the supply voltage.In addition to the detailed structure of the circuits of the two shutdown circuits 1.1, 1.2, the inclusion of the charging circuit 1.3 and of the two discharging circuits 1.4, 1.5 in the load circuit of the shutdown module is schematically illustrated. In addition, the failure protection circuit 5 formed by the two parallel-connected resistors R 97, R 98 is emphasized. The failure protection circuit 5 serves to discharge the load circuit in the event of failure of the 24 V supply voltage 13, wherein the output load voltage 11 is preferably discharged to one third of the input load voltage 10.FIGS. 3 and 4 show, in a representation corresponding to FIG. 2, the two switch-off circuits 1.1, 1.2 in each case in simplified form; FIG. 3 shows the detailed structure of the circuits of the charging circuit 1.3 and of the first discharging circuit 1.4, and FIG. 4 shows the detailed structure of the circuits of the charging circuit 1.3 and of the second discharging circuit 1.5.The charging circuit 1.3 has a similar structure to the respective switch-off circuits 1.1, 1.2, wherein the MOSFET (semiconductor switch) of the charging circuit 1.3, denoted by M9, is actuated via the optocoupler denoted by IC5. Resistor R9 forms the gate series resistor and resistor R99 forms the turn-off resistor in the event of a voltage failure. As an input signal for controlling the charging circuit photocoupler IC5, the charging drive potential DR-CRG is used. In addition to the MOSFET M 9, the charging circuit 1.3 has the resistor cascade comprising the power resistors R 10, R 23, R 24, R 25, R 26 and R 27. The MOSFET M9 and this resistor cascade form the shunt connection between the input load potential VIN and the output load potential VOUT. In addition, the charging voltage potential VCRGis tapped between the MOSFET M 9 and the power resistor cascade.The discharge circuits 1.4, 1.5 are activated after the switch-off circuits 1.1, 1.2 have been switched off; they are constructed in a similar manner to the charge circuit 1.3.The first discharge circuit 1.4 shown in FIG. 3 comprises the MOSFET M7 and the resistor cascade comprising the resistors R17, R18, R19, R20, R21 and R22, which together form the first discharge connection between the output load potential VOUT and the load-side ground potential GBP. The MOSFET M7 is controlled via the optocoupler identified by IC3; the resistor R7 forms the gate series resistor and the resistor R103 forms the switch-off resistor in the event of a voltage failure. As an input signal for controlling the discharge circuit photo coupler IC3, the first discharge driving potential DR-DSC1 is used.The second discharge circuit 1.5 shown in FIG. 4 comprises the MOSFET M8 and the resistor cascade comprising the resistors R11, R12, R13, R14, R15 and R16 which together form the second discharge connection between the output load potential VOUT and the load-side ground potential GBP. The MOSFET M8 is controlled via the optocoupler identified by IC4; the resistor R8 forms the gate series resistor and the resistor R104 forms the switch-off resistor in the event of a voltage failure. As an input signal for controlling the discharge circuit photo coupler IC4, the second discharge driving potential DR-DSC2 is used.The drive input circuit 2.6 shown in FIG. 5 comprises two circuits of comparable construction for processing the first switching signal 12.1 arriving at the terminal X1 and the second switching signal 12.2 arriving at the terminal X2, which circuits have the AND gates IC6, IC7 as logic modules. Both switching signals 12.1, 12.2 are present as 24 V voltages and are lowered to 4.4 V via a voltage divider in each case. The capacitors C8 and C9 protect the input from high frequency noise signals. The diodes D1 and D2 prevent over-voltages at the logic components. The output signals of the drive input circuit 2.6 are the first switching signal potential INT1 associated with the first switching signal 12.1 and the second switching signal potential INT2 associated with the second switching signal 12.2.The two switch-off drivers 2.1, 2.2 shown in FIG. 6 have logic components in the form of AND gates IC10 and IC12, the respective output signal of which drives transistors Q2 and Q3, respectively. In the first switch-off triggering 2.1, the switching signal potential INT1 and the signal supplied by the optocoupler IC9, which results as a function of the input load potential VIN present at the optocoupler IC9 and the output load potential VOUT, enter as input signals at the AND gate IC10. The first switching control potential DR-SW1 is active when the switching signal potential INT1 is active and when the voltage difference between the input load potential VIN and the output load potential VOUT is less than 4V. The circuit of the second switch-off control 2.2 is of equivalent construction to the first switch-off control 2.1, the switching signal potential INT2 and the signal supplied by the optocoupler IC11 also occurring as input signals at the AND gate IC12, which signal likewise arises as a function of the input load potential VIN present at the optocoupler IC9 and the output load potential VOUT. The second switching control potential DR-SW2 is thus active when the switching signal potential INT2 is active and when the voltage difference between the input load potential VIN and the output load potential VOUT is again less than 4 V. The NPN transistor Q2 is connected to the output of the AND gate IC10, and the NPN transistor Q3 is connected to the AND gate IC12. The output signal of the first switch-off control 2.1 originating from the transistor Q2 is the first switching control potential DR-SW1; the output signal of the second switch-off control 2.2 originating from the transistor Q3 is the second switching control potential DR-SW2.The resistors R35, R36, R37, R38, R39 and R43, R44, R45, R46 and R47 serve as series resistors. The resistors R40 and R48 are pull-up resistors; the capacitors C13 and C15 serve for signal stabilization, respectively.Additionally connected to the second switch-off control 2.2 is the overload protection circuit 6, which prevents control in the event of failure or in the event of an unacceptably high drop in the 24 V supply voltage 13.FIG. 7 shows the charging circuit control system 2.3 and the first discharging circuit control system 2.4 and the second discharging circuit control system 2.5. These circuits are constructed in a similar manner from a logic component and the transistor connected to the output of the logic component.The charging circuit control 2.3 has an AND gate IC8 as logic module, to which the first switching signal potential INT1 and the second switching signal potential INT2 are applied on the input side. The charge control potential DR-CRG, which originates from the NPN transistor Q1 and with which the charging circuit 1.3 is controlled, is active when both the first switching signal potential INT1 and the second switching signal potential INT2 are active.The two discharge circuit control units 2.4, 2.5 each have a NAND gate, i.e. a negative AND gate, as logic component. The discharge circuit control units 2.4, 2.5, as in the case of the charge circuit control unit 2.3, also each have an NPN transistor. The first switching signal potential INT1 is present on the input side of the first discharge circuit control units 2.4; the first discharge circuit control unit 2.4 is connected on the output side via the first discharge control potential DR-DSC1 to the first discharge circuit 1.4. The first discharge drive potential DR-DSC1 is active due to the inversion by the NAND gate when the first switching signal potential INT1 is inactive, i.e., interrupted. The switching signal potential INT2 is present on the input side of the second discharge circuit control units 2.5; the second discharge circuit control unit 2.5 is connected on the output side to the second discharge circuit 1.5 via the second discharge control potential DR-DSC2. The second discharge drive potential DR-DSC2 is active due to the inversion by the NAND gate when the second switching signal potential INT2 is inactive, i.e., interrupted.The circuit diagrams or the components of the voltage supply unit 4 are reproduced in FIGS. 8 and 9.FIG. 8 shows the connections X3.1, X3.2, via which the switch-off module is connected to the 24 V supply voltage 13. For input filtering, a CLC element (capacitor C23 coil L1 capacitors C23, C26) is used. For converting the filtered supply voltage 13, which is present between the supply voltage potential V 24P and the control-side ground potential GND, into the control voltage, which is present between the control voltage potential V 5P and the control-side ground potential GND, the first voltage converter, i.e. the controllable DC-DC converter IC 25, is used. The controllable DC-to-DC converter IC 25 can be switched off via a control input connected to the temperature monitoring circuit T. The temperature monitoring circuit T comprises two parallel-connected circuits for temperature deactivation, each having a thermistor NTC. Each of the temperature shut-off circuits comprises a voltage divider of a series resistor R91 or R94 and a thermistor NTC1 or NTC2. When the temperature is overloaded, the thermistor thermistors NTC1 and NTC2 become conductive and switch off the transistors Q8 and Q9; as a result, the voltage across the diode D3 and D4 increases, as a result of which the controllable DC-DC converter IC25 is switched off.FIG. 9 shows the three further voltage converters DCDC 1, DCDC 2 and DCDC 3 of the voltage supply unit 4, which convert the filtered 24 V supply voltage 13 into a floating 12 V semiconductor switch control voltage in each case.FIG. 10 shows the first diagnostic channel 3.1 of the diagnostic unit 3, which supplies the first feedback signal 14.1 at the connections X3.3, X3.4. The circuit arrangement of the first diagnostic channel 3.1 comprises the optocoupler IC19, at which the charging voltage potential VCRGand the output load potential VOUTare present on the input side, the optocoupler IC18, at which the input load potential VINand the interposer potential VSW12are present on the input side, and the optocoupler IC16, at which the output load potential VOUTand the load-side ground potential VGPare present on the input side. At the output side, the optical couplers IC19, IC18 and IC16 are connected to each other as shown in FIG. 10. The resistor R 60 is a series resistor. The resistor R71 is used as a pull-down resistor to safely pull the signal to the control-side ground potential GND in the event of a fault. The capacitor C20 serves for signal stabilization.In order to detect the proper shutdown via the first feedback signal 14.1, the following conditions must simultaneously be fulfilled: a) a voltage must be present across the semiconductor switch (MOSFET) of the charging circuit 1.3, i.e. the voltage difference between the charging voltage potential VCRGand the output load potential VOUTmust be greater than 14 V (the output at the optocoupler IC19 is then active); and b) a voltage must be present across the semiconductor circuit of the first shutdown circuit 1.1, i.e. the voltage difference between the input load potential VINand the interposer potential VSW12must be greater than 14 V (the output at the optocoupler IC18 is then active); and c) the output load voltage 11 must be low, i.e. the voltage difference between the output load potential VOUTand the load-side ground potential GNDPmust not exceed 8 V (the output at the optocoupler IC 16 is then inactive).If all three conditions are simultaneously fulfilled, optocoupler IC15 is driven via AND gate IC17 and NPN transistor Q6, via which optocoupler first feedback signal 14.1 is then output. The feedback signal 14.1 thus signals that no output load voltage 11 is present and at the same time the switching elements of the first disconnection circuit 1.1 and of the charging circuit 1.3 are switched off.FIG. 11 shows the second diagnostic channel 3.2 of the diagnostic unit 3 which is constructed in a manner comparable to the first diagnostic channel 3.1; the latter supplies the second feedback signal 14.2 at the connections X3.5, X3.6. The circuit arrangement of the second diagnostic channel 3.2 comprises the optocoupler IC 24, to which the charging voltage potential VCRGand the output load potential VOUTare present on the input side, the optocoupler IC 23, to which the interposer potential VSW 12and the output load potential VOUTare present on the input side, and the optocoupler IC 21, to which the output load potential VOUTand the load-side ground potential VBPare present on the input side. On the output side, the optical couplers IC24, IC23 and IC21 are connected to each other as shown in FIG. 11. The resistor R89 is a series resistor. The resistor R88 is used as a pull-down resistor in order to safely pull the signal to the control-side ground potential GND in the event of a fault. The capacitor C22 serves for signal stabilization.In order to detect the proper shutdown via the second feedback signal 14.2, the following conditions must simultaneously be fulfilled: a) a voltage must be present across the semiconductor switch (MOSFET) of the charging circuit 1.3, i.e. the voltage difference between the charging voltage potential VCRGand the output load potential VOUTmust be greater than 14 V (the output at the optocoupler IC24is then active); and b) a voltage must be present across the semiconductor circuit of the second shutdown circuit 1.2, i.e. the voltage difference between the interposer potential VSW12and the output load potential VOUTmust be greater than 14 V (the output at the optocoupler IC23is then active); and c) the output load voltage 11 must be low, i.e. the voltage difference between the output load potential VOUTand the load-side ground potential GNDPmust not exceed 8 V (the output at the optocoupler IC 21 is then inactive).If all three conditions are simultaneously fulfilled, optocoupler IC 20 is driven via AND gate IC 22 and NPN transistor Q 7, via which second feedback signal 14.2 is then output. The second feedback signal 14.2 thus signals that no output load voltage 11 is present and at the same time the switching elements of the second disconnection circuit 1.2 and of the charging circuit 1.3 are switched off.The two diagnostic channels 3.1, 3.2 consequently make possible a redundant diagnosis of the switching elements of the charging circuit 1.3 and at the same time a targeted, independent diagnosis of the switching elements of the two switch-off circuits 1.1, 1.2.The second embodiment of the switch-off module according to FIG. 12 differs from the first embodiment in that two charging voltage potentials VCRG, namely the first charging voltage potential VCRG 1 and the second charging voltage potential VCRG 2, are tapped at the charging circuit 1.3. The first charging voltage potential VCRG1 is an input signal for the first diagnostic channel 3.1 and the second charging voltage potential VCRG2 is an input signal for the first diagnostic channel 3.1 and for the second diagnostic channel 3.2.In contrast to the first embodiment, the voltage supply unit 4 of the second embodiment of the switch-off module further comprises, in addition to the first voltage converter for generating the 5 V control voltage, four (instead of three) further voltage converters for generating the 12 V semiconductor switch control voltages. These semiconductor switch control voltages are characterized by the first semiconductor switch control potential V12P-S1, the second semiconductor switch control potential V12P-OUT1, the third semiconductor switch control potential V12P-D, and the fourth semiconductor switch control potential V12P-OUT2.Referring to FIG. 13, the charging circuit 1.3 has two semiconductor switches, namely the first charging circuit semiconductor switch (MOSFET M9) and the second charging circuit semiconductor switch (MOSFET M10). They are controlled via the optocouplers identified by IC 5 or IC 27. The resistors R9 and R107 form gate series resistors and the resistors R99 and R108 form turn-off resistors in the event of a voltage failure. As an input signal for controlling both the charging circuit optocouplers IC 5, IC 27, the charging drive potential DR-CRG is used. In addition to the MOSFETs M 9, M 10, the charging circuit 1.3 has the resistor cascade comprising the power resistors R 10, R 23, R 24, R 25, R 26 and R 27, wherein the second charging circuit semiconductor switch (MOSFET M 10), the first charging circuit semiconductor switch (MOSFET M 9) and this resistor cascade form the shunt connection between the input load potential VIN and the output load potential VOUT. The first charging voltage potential VCRG1is tapped between the first charging circuit semiconductor switch (MOSFET M9) and the power resistor cascade, and the second charging voltage potential VCRG2is tapped between the second charging circuit semiconductor switch (MOSFET M10) and the first charging circuit semiconductor switch (MOSFET M9).FIG. 14 shows the voltage supply unit 4 according to the second embodiment of the shutdown module having the first voltage converter IC 25 for generating the 5 V control voltage and the temperature monitoring circuit T, which has three parallel-connected circuits for temperature shutdown. Each of the temperature shut-off circuits has a voltage divider comprising a series resistor R91, R94 and R109, respectively, and a thermistor NTC1, NTC2 and NTC3, respectively. When the temperature is overloaded, the thermistor thermistors NTC1, NTC2 and NTC3 become conductive and switch off the transistors Q8, Q9 and Q12; as a result, the voltage across the diode D3, D4 and D6 increases, as a result of which the controllable DC-DC converter IC25 is switched off. The shutdown temperature is set to 80° C.FIG. 15 shows the four further voltage converters DCDC 1, DCDC 2, DCDC 3 and DCDC 4 of the voltage supply unit 4 according to the second embodiment of the shutdown module, which convert the filtered 24 V supply voltage 13 into a floating 12 V semiconductor switch control voltage in each case.The diagnostic channels 3.1, 3.2 shown in FIGS. 16 and 17 largely correspond to those according to FIGS. 10 and 11 with the difference in the processing of the charging voltage potential VCRG, which, according to the second embodiment of the switch-off module, is tapped in the form of the first charging voltage potential VCRG1and the second charging voltage potential VCRG2at the charging circuit 1.3.As shown in FIG. 16, the first charging voltage potential VCRG1and the second charging voltage potential VCRG2are applied to the optical coupler IC19on the input side instead of the charging voltage potential VCRGand the output load potential VOUT.In order to detect the proper shutdown via the first feedback signal 14.1 of the diagnostic channel 3.1, the following conditions must simultaneously be fulfilled: a) a voltage must be present across the first charging circuit semiconductor switch (MOSFET M9) of the charging circuit 1.3, i.e. the voltage difference between the first charging voltage potential VCRG1and the second charging voltage potential VCRG2must be greater than 14 V (the output at the optocoupler IC19is then active); and b) a voltage must be present across the semiconductor circuit of the first shutdown circuit 1.1, i.e. the voltage difference between the input load potential VINand the interposer potential VSW12must be greater than 14 V (the output at the optocoupler IC18is then active); and c) the output load voltage 11 must be low, i.e. the voltage difference between the output load potential VOUTand the load-side ground potential GNDPmust not exceed 8 V (the output at the optocoupler IC 16 is then inactive).According to the second embodiment of the shutdown module, as shown in FIG. 17, the second charging voltage potential VCRG2is present at the input side of optocoupler IC24in place of charging voltage potential VCRG.In order to detect the proper shutdown via the second feedback signal 14.2 of the diagnostic channel 3.2, the following conditions must simultaneously be fulfilled: a) a voltage must be present across the second charging circuit semiconductor switch (MOSFET M10) of the charging circuit 1.3, i.e. the voltage difference between the second charging voltage potential VCRG2and the output load potential VOUTmust be greater than 14 V (the output at the optocoupler IC24is then active); and b) a voltage must be present across the semiconductor circuit of the second shutdown circuit 1.2, i.e. the voltage difference between the interposer potential VSW12and the output load potential VOUTmust be greater than 14 V (the output at the optocoupler IC23is then active); and c) the output load voltage 11 must be low, i.e. the voltage difference between the output load potential VOUTand the load-side ground potential GNDPmust not exceed 8 V (the output at the optocoupler IC 21 is then inactive).The two diagnostic channels 3.1, 3.2 according to the second embodiment of the switch-off module enable a specific, independent diagnosis of the switching elements of the two switch-off circuits 1.1, 1.2 and of the charging circuit 1.3.List of reference characters1 Shutdown unit 1.1 First shutdown circuit 1.2 Second shutdown circuit 1.3 Charging circuit 1.4 First discharge circuit 1.5 Second discharge circuit 2 Drive unit 2.1 First shutdown drive 2.2 Second shutdown drive 2.3 Charging circuit drive 2.4 First discharge circuit drive 2.5 Second discharge circuit drive 2.6 Drive input circuit 3 Diagnostic unit 3.1 First diagnostic channel 3.2 Second diagnostic channel 4 Voltage supply unit 5 Failure protection circuit 6 Overload protection circuit 10 Input load voltage 11 Output load voltage 12 Switching signal 12.1 First switching signal 12.2 Second switching signal 13 Supply voltage 14 Feedback signal 14.1 First feedback signal 14.2 Second feedback signal VIN Input load potential VOUT Output load potential VCRG Charging voltage potential VCRG1 First charging voltage potential VCRG2 Second charging voltage potential vsw12 interposer potential V24P supply voltage potential V5P control voltage potential V12P-S1 first semiconductor switch control potential V12P-OUT second semiconductor switch control potential (first embodiment) V12P-OUT1 second semiconductor switch control potential (second embodiment) V12P-D third semiconductor switch control potential V12P-OUT2 fourth semiconductor switch control potential CBP load side ground potential GND control side ground potential INT1 first switching signal potential INT2 second switching signal potential DR-SW1 first switch control potential DR-SW2 second switch control potential DR-CRG charge drive potential DR-DSC1 first Discharge driving potential DR-DSC2 Second discharge driving potential C Capacitor D Diode DCDC Voltage converter (DC) IC Integrated circuit K Terminal (load voltage) L Coil M Metal-oxide-semiconductor field effect transistor (MOSFET) NTC Thermistor Q Transistor R Resistor T Temperature monitoring circuit X Terminal

Claims

Shutdown module for safe shutdown of a DC voltage load which is present in the form of a load voltage as an incoming input load voltage (10) between an input load potential (VIN) and a load-side ground potential (GNDP) and as an outgoing output load voltage (11) between an output load potential (VOUT) and the load-side ground potential (GNDP) at a load circuit of the shutdown module, wherein the shutdown module is configured, when at least one switching signal (12) incoming at the shutdown module is interrupted, to shut down the load circuit by means of a semiconductor-based shutdown unit (1) by interrupting the connection of input load potential (VIN) and output load potential (VOUT), and to output at least one feedback signal (14) identifying the load shutdown, wherein the shutdown module has: - the semiconductor-based shutdown unit (1) with a first shutdown circuit (1.1), a second shutdown circuit (1.2) and a charging circuit (1.3); a drive unit (2) having a drive input circuit (2.6) processing an incoming first (12.1) and an incoming second (12.2) switching signal (12), a first shutdown controller (2.1) for driving the first shutdown circuit (1.1), a second shutdown controller (2.2) for driving the second shutdown circuit (1.2) and a charging circuit drive (2.3) for driving the charging circuit (1.3); a diagnostic unit (3) having a first diagnostic channel (3.1) for outputting a first feedback signal (14.1) and a second diagnostic channel (3.2) for outputting a second feedback signal (14.2); and a voltage supply unit (4) connected to a supply voltage (13) for supplying voltage to the units of the shutdown module; wherein - the connection between the input load potential (VIN) and the output load potential (VOUT) comprises a main connection connected via the two shutdown circuits (1.1, 1.2) and a secondary connection connected in parallel via the charging circuit (1.3), and - the first shutdown circuit (1.1) and the second shutdown circuit (1.2) each have a semiconductor circuit with at least one semiconductor switch, wherein the main connection between the input load potential (VIN) and the output load potential (VOUT) is formed by the series-connected semiconductor circuits of the first shutdown circuit (1.1) and the second shutdown circuit (1.2), and wherein the semiconductor switch or switches of the respective semiconductor circuit are connected to the respectively associated shutdown controller (2.1, 2.2) via a respective optocoupler for controlling the activation or blocking of the main connection, and - the first switch-off controller (2.1) and the second switch-off controller (2.2) are configured to activate the main connection if both switching signals (12.1, 12.2) arriving at the drive unit 2 are present and the voltage difference between the input load potential (VIN) and the output load potential (VOUT) falls below a predefined threshold value, and - the charging circuit (1.3) comprises at least one semiconductor switch and at least one power resistor which, connected in series, form the shunt connection between the input load potential (VIN) and the output load potential (VOUT), wherein the semiconductor switch of the charging circuit (1.3) is connected to the charging circuit drive (2.3) via an optocoupler in order to control the activation or blocking of the shunt connection, and - the charging circuit drive (2.3) is configured, activating the secondary connection by controlling the optocoupler of the charging circuit (1.3) when both switching signals (12.1, 12.2) arriving at the control unit 2 are present, and - an intermediate switch potential (VSW12) is present in the main connection between the semiconductor switch of the first disconnection circuit (1.1) and the second disconnection circuit (1.2), and - a charging voltage potential (VCRG) is present in the secondary connection between the at least one semiconductor switch and the power resistor or resistors of the charging circuit (1.3), and - the first diagnostic channel (3.1) is configured to signal proper disconnection of the load circuit via the first feedback signal (14.1), if the voltage difference between the charging voltage potential (VCRG) and the output load potential (VOUT) exceeds a predetermined threshold value and the voltage difference between the input load potential (VIN) and the interposer potential (VSW12) exceeds a predetermined threshold value and the voltage difference between the output load potential (VOUT) and the load-side ground potential (GNDP) falls below a predetermined threshold value, and - the second diagnostic channel (3.2) is configured to signal a proper disconnection of the load circuit via the second feedback signal (14.2), when the voltage difference between the charging voltage potential (VCRG) and the output load potential (VOUT) exceeds a predetermined threshold value, and the voltage difference between the interposer potential (VSW12) and the output load potential (VOUT) exceeds a predetermined threshold value, and the voltage difference between the output load potential (VOUT) and the load-side ground potential (GNDP) falls below a predetermined threshold value.Switch-off module according to Claim 1, characterized in that the switch-off unit 1 furthermore has a first discharge circuit (1.4) and a second discharge circuit (1.5), and the drive unit (2) furthermore has a first discharge circuit drive (2.4) for driving the first discharge circuit (1.4) and a second discharge circuit drive (2.5) for driving the second discharge circuit (2.4), - the first discharge circuit (1.4) comprising at least one semiconductor switch and at least one power resistor which, connected in series, form a first discharge connection between the output load potential (VOUT) and the load-side ground potential (GBP), the semiconductor switch of the first discharge circuit (1.4) being connected to the first discharge circuit drive (2.4) via an optocoupler in order to control the activation or blocking of the first discharge connection, and wherein the first discharge circuit drive (2.4) is configured to activate the first discharge connection by driving the optocoupler of the first discharge circuit (1.4) when the first switching signal (12.1) arriving at the drive unit (1) is interrupted, and - wherein the second discharge circuit (1.5) comprises at least one semiconductor switch and at least one power resistor, which, connected in series, form a second discharge connection, connected in parallel with the first discharge connection, between the output load potential (VOUT) and the load-side ground potential (GNDP), wherein the semiconductor switch of the second discharge circuit (1.5) is connected to the second discharge circuit drive (2.5) via an optocoupler in order to control the activation or blocking of the second discharge connection, and wherein the second discharge drive (2.5) is configured, activating the second discharge connection by driving the optocoupler of the second discharge circuit (1.5) when the second switching signal (12.2) arriving at the driving unit 2 is interrupted.Switch-off module according to Claim 2, characterized in that the size of the power resistors in the first discharge circuit (1.4) and in the second discharge circuit (1.5) are dimensioned such that the activated discharge connections reduce the output load voltage (11) to one third of the input load voltage (10).Switch-off module according to one of Claims 1 to 3, characterized in that each of the semiconductor circuits of the first switch-off circuit (1.1) and of the second switch-off circuit (1.2) has in each case three semiconductor switches connected in parallel.Shutdown module according to one of Claims 1 to 4, characterized in that the shutdown unit (1) furthermore has a failure protection circuit (5) having a failure discharge connection between the output load potential (VOUT) and the load-side ground potential (GNDP), the failure discharge connection having at least one power resistor or two power resistors connected in parallel.Shutdown module according to one of Claims 1 to 5, characterized in that the activation unit (2) furthermore has an overload protection circuit (6) which is connected to the second shutdown activation (2.2) and is set up to deactivate the second shutdown activation (2.2) if the supply voltage (13) of the voltage supply unit (4) falls below a predefined threshold value.Switch-off module according to one of Claims 1 to 6, characterized in that the voltage supply unit (4) comprises a first voltage converter (IC25) for converting the supply voltage (13) into a control voltage for supplying voltage to the drive unit (2) and to the diagnostic unit (3) and also further voltage converters (DCDC1, DCDC2, DCDC3, DCDC4) for converting the supply voltage (13) into potential-free semiconductor switch control voltages.Disconnection module according to Claim 7, characterized in that a temperature monitoring circuit (T) is integrated into the voltage supply unit (4), the first voltage converter (IC25) having a control input to which the temperature monitoring circuit (T) is connected.Shutdown module according to Claim 8, characterized in that the temperature monitoring circuit (T) consists of two or three parallel-connected circuits which each have a thermistor (NTC1, NTC2, NTC3) for temperature detection.Switch-off module according to one of Claims 1 to 9, characterized in that the predefined threshold values of the voltage differences are each set to a value of 4 V ± 1 V, 8 V ± 1 V or 14 V ± 1 V.

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