DE102021113589A1 - ELECTRONIC POWER DISTRIBUTOR - Google Patents

Abstract

The disclosure relates to an electronic current distributor for supplying power to a plurality of load channels, having a first electronic switch with a first switchable current path, which is connected between a power supply connection and a first load channel of the plurality of load channels and is designed to protect the first load channel from overcurrent; an electrical bypass path that is connected in parallel to the first switchable current path of the first electronic switch between the power supply connection and the first load channel, wherein the electrical bypass path has an electromechanical power switch that is configured, in the event of a short circuit of the first load channel, a by switching off the first switchable current path in the electrical bypass path, to reduce short-circuit power commutated via an arc in the electromechanical circuit breaker.

Description

technical field

The disclosure relates to an electronic power distributor for powering a plurality of load channels and a method for powering a plurality of load channels. In particular, the disclosure relates to the quiescent current supply and the protection of MOSFETs via bimetallic circuit breakers.

State of the art

For future power distributors, the combination of relays and fuses is to be replaced by MOSFET switches for electronic terminal switching and electronic protection of the load channels. This results in the following problems: 1) Terminal 30 channels (i.e. channels that are connected to battery voltage) must also be supplied with battery voltage in the idle state. However, continuous switching of the MOSFETs with active short-circuit protection at the same time contributes to the quiescent current consumption of the electronic current distributor. 2) In the case of short-circuit shutdown in active mode, the MOSFETs can be damaged by inductive overvoltage to the extent that they may no longer be able to separate. A protective circuit is therefore typically provided for overvoltage protection. However, there are cases in which the effective inductance in the event of a short circuit is not really known and the design of the protective circuit is therefore problematic. In the case of high short-circuit currents, the critical voltage for MOSFETs can also be exceeded. 3) When the vehicle is at rest, some rest-active loads may draw so much current that the battery will drain too quickly. A channel-specific measurement for error detection is therefore desirable. So far, however, this has been very complex, since currents in the single-digit mA range have to be resolved for each channel.

4) For over the air (OTA) software upgrades, a dedicated post-upgrade load reset is desirable. So far, only entire terminal 30-F groups can be switched off via a terminal relay.

Description of the invention

It is an object of the invention to create a concept for an electronic power distributor, in particular for the vehicle electrical system, which overcomes the problems described above.

In particular, it is an object of the invention to design an electronic power distributor for an electronic terminal circuit and electronic protection of the load channels, which satisfies the safety requirements for functional safety (FUSI) in vehicle electrical systems.

This object is solved by the objects with the features according to the independent claims. Advantageous embodiments are the subject matter of the dependent claims, the description and the drawings.

The disclosure is based on the idea of wiring a bypass consisting of diodes for coupling together with a bimetal power switch (circuit breaker) in parallel with the MOSFET channels. The bypass fulfills the following two tasks: 1) secured quiescent current supply (connection to the battery terminal). 2) If a short circuit occurs in the active mode, the MOSFET breaks with its fast turn-off. The current then commutates to the bypass so that no overvoltage is generated for the MOSFET. The (electromechanical) circuit breaker then interrupts the bypass. An arc is created between its contacts. The arc dissipates the inductive energy in the circuit and limits the overvoltage to the arc voltage. This is typically less than 30V with a 1mm contact air gap. The inductive energy is therefore converted in the circuit breaker and not in the MOSFET. A short overvoltage impulse can only occur at the moment when the arc breaks. This can then be implemented via avalanche in the MOSFET or via a small Transil diode.

One of the technical advantages of this concept is that such an arc can convert comparatively high inductive energies in the circuit breaker. Another advantage is the realization of a redundant overvoltage protection of the MOSFETs via the circuit breaker and the Transil diode for FUSI channels with diversity. Furthermore, a voltage supply of terminal 30 in sleep mode, i.e. quiescent current mode, can be achieved without its own quiescent current contribution.

According to a first aspect, the object described above is achieved by an electronic current distributor for supplying power to a plurality of load channels, having: a first electronic switch with a first switchable current path, which is connected and configured between a power supply connection and a first load channel of the plurality of load channels to secure the first load channel against overcurrent; an electrical bypass path parallel to the first switchable current path of the first electronic switch is connected between the power supply connection and the first load channel, wherein the electrical bypass path has an electromechanical circuit breaker that is designed, in the event of a short circuit in the first load channel, to switch off the first switchable current path into the reduce electrical bypass path commutated short-circuit power via an arc in the electromechanical circuit breaker.

Such an electronic current distributor offers the technical advantage that it can convert comparatively high inductive energies via the arc in the circuit breaker. The electronic power distributor can ensure redundant overvoltage protection of the MOSFETs via the circuit breaker and channel-specific transil diodes for FUSI channels with diversity. In addition, the bypass path can be used to supply voltage to terminal 30 in sleep mode without making a contribution to the quiescent current.

The electronic power distributor thus satisfies the safety requirements for functional safety (FUSI) in vehicle electrical systems.

According to an exemplary embodiment of the electronic power distributor, the electromechanical circuit breaker has a bimetallic relay that is designed to convert thermal heating due to the short-circuit power into a mechanical movement to open a contact of the bimetallic relay.

This achieves the technical advantage that the bimetallic relay can efficiently convert the short-circuit current into thermal energy and dissipate it via the mechanical movement to open the contact of the bimetallic relay and the subsequent arcing via the contacts of the relay.

According to an exemplary embodiment of the electronic power distributor, the electromechanical circuit breaker is designed to limit an overvoltage that occurs when the first load channel shorts to a voltage of the arc.

This achieves the technical advantage that the overvoltage can be limited to a defined value and the electronic power distributor cannot be destroyed.

According to an exemplary embodiment of the electronic power distributor, the electronic power distributor comprises a first transil diode connected in parallel with the first switchable current path of the first electronic switch and in parallel with the reverse-bias electrical bypass path between the power supply terminal and the first load channel.

This achieves the technical advantage that redundant dissipation of the short-circuit current is made possible via this first Transil diode. First, the short-circuit current is routed through the circuit breaker. If this is no longer possible, the short-circuit current can also be routed via the first Transil diode.

According to an exemplary embodiment of the electronic power distributor, the first Transil diode is designed to reduce an overvoltage pulse that occurs when the arc breaks off in the electromechanical circuit breaker.

This achieves the technical advantage that only a small portion of the short-circuit energy needs to be dissipated via the Transil diode, while the majority of this energy is dissipated in the arc of the electromechanical circuit breaker.

According to an exemplary embodiment of the electronic power distributor, the first transil diode is designed to absorb part of the short-circuit power in the short-circuit of the first load channel until a leakage inductance of the bypass path is overcome and the short-circuit power is reduced via the arc in the electromechanical circuit breaker.

This achieves the technical advantage that the part of the short-circuit energy that builds up can be dissipated via the Transil diode before the electromechanical circuit breaker can react. This does not lead to damage to the electronic switch or the MOSFET transistor in the early stages of a short circuit.

According to an exemplary embodiment of the electronic current distributor, the first Transil diode is designed to absorb and dissipate at least part of the short-circuit power in the event of damage to the electromechanical circuit breaker.

This achieves the technical advantage that the electronic power distributor meets the requirements of functional safety (FUSI), since both the circuit breaker and the first Transil diode are available in a redundant manner in order to reduce the short-circuit energy.

According to an exemplary embodiment of the electronic power distributor, the electronic power distributor comprises a diagnostic capacitor which is connected in parallel to the first switchable current path of the first electronic switch and is designed to detect a voltage present on the first switchable current path when the first switchable current path is switched off for a Detect diagnosis by a microcontroller.

This achieves the technical advantage that the voltages present on the corresponding current paths can be detected via the diagnostic capacitor. This information can be used to determine whether the current paths are already damaged, so that an exchange can be initiated in good time.

According to an exemplary embodiment of the electronic power distributor, the electronic power distributor comprises a second electronic switch with a second switchable current path, which is connected between a second load channel of the plurality of load channels and the power supply connection and is designed to protect the second load channel against overcurrent, the electrical bypass -Path is also connected in parallel to the second switchable current path of the second electronic switch between the power supply terminal and the second load channel.

This achieves the technical advantage that a short circuit across different load channels can be eliminated efficiently via the circuit breaker.

According to an exemplary embodiment of the electronic power distributor, the electrical bypass path has a branch that allows the electrical bypass path to branch from a main path to the power supply connection into a first sub-path to the first load channel and a second sub-path to the second load channel, wherein the electromechanical circuit breaker is arranged in the main path of the electrical bypass path.

This achieves the technical advantage that only one circuit breaker needs to be provided for a plurality of load channels, which makes the electronic current distributor very cost-efficient.

According to an exemplary embodiment of the electronic power distributor, the electronic power distributor comprises a first diode, which is arranged in the first sub-path of the electrical bypass path and is connected in the forward direction from the power supply connection to the first load channel, the first diode being formed in the to decouple the first load channel from the second load channel in order to switch off the first load channel independently of the second load channel in the event of a short circuit in the first load channel.

This achieves the technical advantage that the various load channels are decoupled with regard to a short circuit, so that a short circuit in one channel does not affect another channel.

According to an exemplary embodiment of the electronic power distributor, the first electronic switch is designed as a first MOSFET transistor; and the second electronic switch is in the form of a second MOSFET transistor.

The technical advantage that can be achieved in this way is that the electronic current distributor can be implemented inexpensively and with little effort using standard components such as MOSFET transistors, which are available with low channel resistances.

According to an exemplary embodiment of the electronic power distributor, the electrical bypass path has a p-type MOSFET transistor connected in series with the electromechanical power switch, which is designed to switch off the electrical bypass path in the event of a quiescent current violation.

This achieves the technical advantage that the bypass path can be switched off efficiently if the quiescent current is violated, so that the battery does not discharge unintentionally.

According to an exemplary embodiment of the electronic current distributor, the electrical bypass path has a measuring resistor connected in series with the electromechanical power switch and the p-type MOSFET transistor, which is designed to indicate a quiescent current violation via a current flow through the measuring resistor.

This achieves the technical advantage that a quiescent current violation can be efficiently determined via the measuring resistor by determining a voltage drop across the measuring resistor. Depending on the voltage drop, a correspondingly high current flows through the bypass path.

According to an exemplary embodiment of the electronic power distributor, the electronic power distributor comprises a comparator, whose inputs are connected in parallel to the measuring resistor, and which is designed to indicate a current flow through the measuring resistor in the event of a quiescent current violation via a state change at the output of the comparator to a control circuit for diagnosis.

This achieves the technical advantage that the comparator can be used to efficiently determine whether there is a quiescent current violation.

According to a second aspect, the object described above is achieved by a method for supplying power to a plurality of load channels via an electronic power distributor, the electronic power distributor having the following: a first electronic switch with a first switchable current path, which is connected between a power supply connection and a first load channel plurality of load channels is switched; an electrical bypass path connected in parallel to the first switchable current path of the first electronic switch between the power supply connection and the first load channel, the electrical bypass path having an electromechanical power switch, the method comprising: securing the first load channel from a Short circuit due to the first switchable current path of the first electronic switch being switched off; and in the event of a short circuit in the first load channel, dissipation of a short circuit power of the first load channel, commutated by switching off the first switchable current path into the electrical bypass path, via an arc in the electromechanical circuit breaker.

Such a method offers the technical advantage that comparatively high inductive energies can be converted via the arc in the circuit breaker in order to dissipate the short-circuit energy. The procedure allows a redundant design according to the FUSI criteria. In particular, the electronic power distributor can ensure redundant overvoltage protection for the MOSFETs via the circuit breaker and channel-specific Transil diodes for FUSI channels with diversity. Furthermore, such a method allows a voltage supply of the terminal 30 in the sleep mode via the bypass path without its own quiescent current contribution.

According to a third aspect, the object is achieved by a computer program with a program code for executing the method according to the second aspect on a controller, in particular an electronic security circuit or an EFASic.

This achieves the technical advantage that the computer program can easily be run on a controller, such as the electronic safety circuit or EFASic.

character list

• 1 eine schematische Darstellung eines elektronischen Stromverteilers 100 gemäß der Offenbarung;
• 2 eine schematische Darstellung eines elektronischen Stromverteilers 200 gemäß der Offenbarung;
• 3 eine schematische Darstellung eines elektronischen Stromverteilers 300 gemäß der Offenbarung;
• 4 eine Darstellung des Stromverlaufs 401 und des Spannungsverlaufs 402 einer beispielhaften Ansteuerung des elektronischen Stromverteilers 300 aus 3; und
• 5 eine schematische Darstellung eines Verfahrens 500 zur Stromversorgung einer Mehrzahl von Lastkanälen gemäß der Offenbarung.

The invention is described in more detail below using exemplary embodiments and the figures. In the figures show:

• 1 a schematic representation of an electronic power distributor 100 according to the disclosure;
• 2 a schematic representation of an electronic power distributor 200 according to the disclosure;
• 3 a schematic representation of an electronic power distributor 300 according to the disclosure;
• 4 shows a representation of the current profile 401 and the voltage profile 402 of an exemplary activation of the electronic current distributor 300 3 ; and
• 5 FIG. 5 is a schematic representation of a method 500 for powering a plurality of load channels according to the disclosure.

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the concept of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. Furthermore, it is understood that the features of the various exemplary embodiments described herein can be combined with one another, unless specifically stated otherwise.

Detailed description

The aspects and embodiments are described with reference to the drawings, wherein like reference numbers generally refer to like elements. In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of one or more aspects of the invention. However, it may be apparent to a person skilled in the art that one or more aspects or embodiments are disclosed with a lesser degree of specific detail can be executed. In other instances, well-known structures and elements are shown in schematic form in order to facilitate describing one or more aspects or embodiments. It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the concept of the present invention.

In this disclosure, criteria and requirements for functional safety (FUSI) in vehicles are described. Functional safety describes that part of the safety of a system that depends on the correct functioning of the safety-related system and other risk-reducing measures. In the automotive sector, functional safety is usually described in the form of ASIL (“Automotive Safety Integrity Level”) classes. The ASIL classification is composed of various factors, these are 1) "Severity - S" according to the severity of the fault, the hazard to the user or the environment; 2) "Exposure - E" according to the probability of occurrence, ie frequency and/or duration of the operating condition; 3) "Controllability - C" according to the controllability of the error. Four different ASIL levels result from these factors: ASIL A: recommended failure probability of less than 10 ^-6 / hour; ASIL B: recommended probability of failure less than 10 ^-7 / hour; ASIL C: required probability of failure less than 10 ^-7 / hour; ASIL D: required probability of failure less than 10 ^-8 / hour.

Power distributors are described in this disclosure. A power distributor is a device or an arrangement, e.g. on a printed circuit board, in which fuse and switching elements for the distribution of electrical energy, primarily in the area of the low-voltage network, are housed. It is in almost every vehicle. Electrical lines run from power distributors either directly to the points of consumption, for example to the sensors, the fan or the interior lighting in the vehicle, or to the next subordinate power distributor.

Electronic switches are described in this disclosure. An electronic switch, also known as an analog switch or semiconductor switch, is part of an electronic circuit that implements the function of an electromechanical switch. Field effect transistors (FETs), e.g. metal-oxide-semiconductor FETs, and bipolar transistors and diodes can be used as switching elements. In a broader sense, thyristors and semiconductor relays can also be used as electronic switches.

In this disclosure, metal-oxide-semiconductor field effect transistors are described. A metal-oxide-semiconductor field effect transistor (MOSFET) is one of the field effect transistors with an insulated gate and is a type of transistor that is defined by a stack of layers made up of a metal gate electrode, a semiconductor and the oxidic dielectric in between. This represents a metal-insulator-semiconductor structure. The current flow in the semiconductor area between the two electrical connections drain and source is controlled via a control voltage (gate-source voltage) or control potential (gate potential) at a third connection, the so-called gate. This is electrically insulated from the semiconductor (and thus from the drain and source) by a dielectric.

Electromechanical circuit breakers, in particular bi-metal circuit breakers, are described in this disclosure. An electromechanical circuit breaker according to this disclosure is an overcurrent protection device in the electrical installation or in the vehicle electrical system. Electromechanical miniature circuit breakers are used in low-voltage networks to protect lines from damage caused by heating due to excessive current. In the case of bi-metal circuit breakers, tripping occurs in the event of an overload, as described below. If the specified nominal value of the current flowing through the circuit breaker is significantly exceeded for a longer period of time, the circuit breaker is switched off. The time to trip depends on the magnitude of the overcurrent; in the case of a high overcurrent, it is shorter than when the rated current is only slightly exceeded. A bimetal is used for triggering, which bends when heated by the current flowing through it and triggers the switch-off mechanism (thermal triggering).

Transil diodes are described in this disclosure. Suppressor diodes, also known as "Transient Voltage Suppressors" (TVS) or Transil diodes, are diodes used to protect electronic circuits from brief voltage pulses. Such voltage pulses can occur in lines connected to the circuit as a result of switching processes in the network or near lightning strikes. The voltage that is briefly reached can be sufficient to destroy semiconductor components in the circuit. Transil diodes become conductive when a component-specific voltage threshold is exceeded. The current of the pulse is routed past the component to be protected by parallel switching. As a result, no destructive voltage can build up above the breakdown voltage of the Transil diode. In normal operation, this diode behaves, apart from a low leakage current and an additional capacitance, which is particularly disruptive in high-frequency applications, neutral.

1 10 shows a schematic representation of an electronic power distributor 100 according to the disclosure. The electronic power distributor 100 is used to supply power to a plurality of load channels 101, 102.

The electronic power distributor 100 includes a first electronic switch 110 with a first switchable current path 111, which is connected between a power supply connection 150 and a first load channel 101 of the plurality of load channels 101, 102 and is designed to protect the first load channel 101 against overcurrent.

The electronic power distributor 100 includes an electrical bypass path 140 which is connected in parallel to the first switchable current path 111 of the first electronic switch 110 between the power supply connection 150 and the first load channel 101 . The electrical bypass path 140 has an electromechanical circuit breaker 143, which is designed, in the event of a short circuit in the first load channel 101, to switch off the first switchable current path 111 in the electrical bypass path 140 short-circuit power commutated via an arc 144 in the electromechanical Dismantle circuit breaker 143.

The power supply connection 150 can comprise, for example, a mains voltage connection of a vehicle, for example a 12V battery terminal.

In the embodiment of 1 the electronic power distributor 100 includes a second electronic switch 120 with a second switchable current path 121, which is connected between the power supply connection 150 and a second load channel 102 of the plurality of load channels 101, 102 and is designed to protect the second load channel 101 against overcurrent.

The electromechanical circuit breaker 143 can also be designed, in the event of a short circuit in the second load channel 102, to dissipate short-circuit power commutated into the electrical bypass path 140 by switching off the second switchable current path 121 via an arc 144 in the electromechanical circuit breaker 143.

The electromechanical power switch 143 can have a bimetallic relay, which is designed to convert thermal heating due to the short-circuit power into a mechanical movement for opening a contact of the bimetallic relay.

The electromechanical power switch 143 can be designed to limit an overvoltage that occurs when the first load channel 101 shorts to a voltage of the arc 144 .

The electronic current distributor 100 may include a first transil diode 112 connected in parallel with the first switchable current path 111 of the first electronic switch 110 and in parallel with the reverse electrical bypass path 140 between the power supply terminal 150 and the first load channel 101 .

The first transil diode 112 can be designed to dissipate an overvoltage pulse that occurs when the arc 144 breaks off in the electromechanical circuit breaker 143 .

The first Transil diode 112 can be designed to absorb part of the short-circuit power in the short-circuit of the first load channel 101 until a leakage inductance 113 of the electrical bypass path 140 is overcome and the short-circuit power via the arc 144 in the electromechanical power switch 143 is reduced.

The first transil diode 112 can be designed to absorb and dissipate at least part of the short-circuit power in the event of damage to the electromechanical circuit breaker 143 .

The electronic power distributor 100 may include a second transil diode 122 connected in parallel with the second switchable current path 121 of the second electronic switch 120 and in parallel with the reverse electrical bypass path 140 between the power terminal 150 and the second load channel 102 .

The second Transil diode 122 can be designed to dissipate an overvoltage pulse that occurs when the arc 144 breaks off in the electromechanical circuit breaker 143 .

The second Transil diode 112 can be designed to absorb part of the short-circuit power in the short-circuit of the second load channel 102 until a leakage inductance 123 of the electrical bypass path 140 is overcome and the short-circuit power via the arc 144 in the electromechanical power switch 143 is reduced.

The second transil diode 122 can be formed, at least in part, in the event of damage to the electromechanical circuit breaker 143 absorb and dissipate the short-circuit power.

As described above, the electronic current distributor 100 can include a second electronic switch 120 with a second switchable current path 121, which is connected between a second load channel 102 of the plurality of load channels 101, 102 and the power supply connection 150 and is designed to have the second load channel 102 in front protect against overcurrent. The electrical bypass path 140 is also connected in parallel to the second switchable current path 121 of the second electronic switch 120 between the power supply connection 150 and the second load channel 102 .

The electronic power distributor 100 includes in the representation of 1 an exemplary number of two load channels 101, 102. Each channel 101, 102 is protected by a corresponding electronic switch 110, 120 against short circuits or overcurrents. The electronic power distributor 100 is used to connect the respective load paths to the power supply, for example interior lighting, cooling, a window lift system, etc. of the vehicle. Each load channel 101, 102 can be connected to the voltage supply connection or the voltage supply terminal 150 in order to supply the corresponding load channel and thus the load connected to it with current. In 1 an exemplary number of two load channels 101, 102 are shown. Of course, other configurations with a different number of load channels can also be implemented, e.g. a configuration with three load channels, such as in 3 shown or a configuration with 4, 5, 6, 7, 8 or more channels. It goes without saying that a configuration of only one load channel can also be implemented and is included in this disclosure.

The electrical bypass path 140 may have a branch that branches the electrical bypass path 140 from a main path 140 to the power supply terminal 150 into a first sub-path 141 to the first load channel 101 and a second sub-path 142 to the second load channel 102 . The electromechanical power switch 143 can be arranged in the main path 140 of the electrical bypass path, as in FIG 1 shown.

The electronic power distributor 100 may further include a first diode 145 that may be arranged in the first sub-path 141 of the electrical bypass path 140 and connected in the forward direction from the power supply terminal 150 to the first load channel 101 . The first diode 145 can be designed to decouple the first load channel 101 from the second load channel 102 in order to switch off the first load channel 101 independently of the second load channel 102 in the event of a short circuit in the first load channel 101 .

The electronic power distributor 100 may further include a second diode 146 that may be arranged in the second sub-path 142 of the bypass electrical path 140 and connected in the forward direction from the power supply terminal 150 to the second load channel 102 . The second diode 146 can be designed to decouple the second load channel 102 from the first load channel 101 in order to switch off the second load channel 102 independently of the first load channel 101 in the event of a short circuit in the second load channel 102 .

The first electronic switch 110 can be formed as a first MOSFET transistor M1, as in FIG 1 shown. The second electronic switch 120 can be formed as a second MOSFET transistor M2, as in FIG 1 shown. Both MOSFETs can be p-channel or n-channel MOSFETs.

The electronic power distributor 100 can also have a diagnostic capacitor 214, as shown in FIG 2 described in more detail, which is connected in parallel to the first switchable current path 111 of the first electronic switch 110, and is designed to detect a voltage present on the first switchable current path 111 when the first switchable current path 111 is switched off for a diagnosis by a microcontroller 260.

The electrical bypass path 140 may further include a p-type MOSFET transistor 341 connected in series with the electromechanical power switch 143, as shown in FIG 3 shown configured to turn off the electrical bypass path 140 in the event of a quiescent current violation. A quiescent current violation occurs, for example, when the vehicle is in "sleeping mode", ie in rest mode, for example when the ignition key is removed, but some current consumers are still active and draw a current through the battery that is above a predetermined tolerable threshold . This threshold can be set, for example, in such a way that small currents can be drawn from the battery, but not larger currents that exceed the tolerable threshold and lead to the battery being discharged too quickly in the idle state, with the risk of total discharge in the idle state.

The electrical bypass path 140 may include a sense resistor 342 in series with the electromechanical power switch 143 and the p-type MOSFET transistor 341, as shown in FIG 3 shown, which is designed to indicate a current flow through the measuring resistor 342 a quiescent current violation.

The electronic current distributor 100 can have a comparator 343, as in FIG 3 shown, the inputs of which are connected in parallel to the measuring resistor 342, and which is designed to display a current flow through the measuring resistor 342 in the event of a quiescent current violation via a state change at the output of the comparator 343 to a control circuit 360 for diagnosis.

The mode of operation of the electronic current distributor 100 is explained below in accordance with FIG 1 described in more detail.

The MOSFETs M1 and M2 are the electronic switches of the electronic current distributor 100. The “SW-Defined Fusing”, i.e. the software-defined securing of the channels, can be carried out via these, which takes place in the active mode. The diodes D1, 145 and D2, 146 are provided to decouple the two channels so that they can be switched off independently.

In a conventional arrangement, the circuit breaker 143 and the diodes D1, D2 145, 146 do not exist. In the event of a short-circuit shutdown by MOSFETs M1 or M2, the short-circuit current commutes to the Transil diodes TD1, 112 or TD2, 122. The voltage drop across the Transil diodes 112, 122 depends on the one hand on the threshold value of the Transil diodes, e.g. 33V, on the other hand from the voltage drop across the channel resistance of the Transil diodes. Due to the short-circuit current, this can be so high that the voltage across the Transil diodes and thus across the MOSFETs is above the critical value of 40V, for example, i.e. the overvoltage resistance of the MOSFETs. This effect is all the more pronounced the higher the inductance in the short-circuit loop to be switched off.

With the bypass 140 via the circuit breaker 143 according to the inventive solution, this potential overvoltage situation does not arise: If, in the active case, a short circuit occurs, e.g. at L1, i.e. in the first load channel 101, the MOSFET M1 disconnects. The current then commutes to the bypass 140 consisting of D1, 145 and the circuit breaker 143. For this, only the leakage inductance of the bypass circuit 140 has to be overcome at first. The effective energy that has to be converted in a (small) Transil diode TD1, 112 is very small and is determined by the magnitude of the leakage inductance (approximately in the pH range). In the bypass 140, the (electromechanical) circuit breaker 143 then interrupts the current that builds up. An arc 144 is created between its contacts. The arc 144 reduces the inductive energy in the circuit (input and output inductance) and limits the overvoltage to the arc voltage . This is typically less than 30V with a 1mm contact air gap. The inductive energy is thus converted in the circuit breaker 143 and not in the Transil diode 112. A short overvoltage pulse can only occur at the moment when the arc 144 breaks off. However, this can be dissipated in a small or no Transil diode 112, since it occurs at a current close to 0A, and thus the voltage drop across the channel of the Transil diode 112 does not take effect.

The principle of the circuit breaker 143 or thermal circuit breaker is based on the conversion of the thermal heating caused by overcurrent into a mechanical movement that leads to the opening of a contact. For this purpose, e.g. bimetal strips or so-called "click discs" are used. Since the measured variable is the temperature, the reaction speed of the thermal circuit breaker depends on the outside temperature. However, the fact that the thermal circuit breaker trips more quickly at higher temperatures is appropriate insofar as the thermal reserve of the cable is correspondingly lower at higher temperatures.

However, this has no effect on the protective function for the transistor, since the current commutes very quickly (i.e. in the µs range) to the circuit breaker 143 when the MOSFET is switched off. Its response times are in the ms range.

Aspects relating to functional safety (FUSI) are described below, which can be complied with using the electronic current distributor 100 presented here.

For many applications, the technical safety goal is that it must be possible to switch off in the event of overcurrents or undervoltages.

If a MOSFET has suffered overvoltage damage, it may no longer be able to reliably interrupt the circuit. A safety concept for the protective circuit is therefore necessary. In the solution presented here, the inductive energy can be dissipated via three mechanisms: 1. In the arc of the circuit breaker 143; 2. In the transil diode 112; 3. Due to avalanche breakdown in MOSFET M1, but only a few times because the avalanche breakdown pre-damages the MOSFET.

What is positive for the FUSI is that different mechanisms (ie diversity) are available here. For the FUSI, however, a diagnosis should be coverage can be supplemented so that latent errors can be discovered.

Such a diagnostic circuit is in 2 described in more detail.

2 12 shows a schematic representation of an electronic power distributor 200 according to the disclosure. The electronic power distributor 200 corresponds to that in 1 described electronic power distributor 100, but also has a diagnostic circuit.

This includes a diagnostic capacitor C1 214, which is connected in parallel to the first switchable current path 111 of the first electronic switch 110 and is designed to detect a voltage present on the first switchable current path 111 when the first switchable current path 111 is switched off for a diagnosis by a Microcontroller 260 to detect.

A parallel connection of a diode 215 and a resistor 216 is in the example 2 connected in series to the diagnostic capacitor 214. The diagnostic circuit can be used not only in the first load channel 101, as here in 2 shown, but also in other load channels, such as the second load channel 102, but what in 2 is not shown.

The functionality of the diagnostic circuit is described below.

A “sample and hold” capacitor C1, 214 is reserved here for diagnostic coverage. This holds the maximum drain-source voltage of the MOSFET M1, which occurs when it is switched off, so that it can be read out via a microcontroller (μC) 260. After each switch-off process, μC 260 can therefore measure whether the protective circuit consisting of first transil diode 112 and circuit breaker 143 has failed, and MOSFET M1 has thus been driven into avalanche.

For capacitive loads, a diagnosis is also possible in the initialization phase of the vehicle. For this purpose, the threshold for the rapid shutdown of the MOSFETs M1, M2 can be set to such a low value that it is triggered by the inrush current in the capacitive load. After the MOSFET M1 has been switched off due to the inrush current, the voltage across C1, 214 is then measured. If this is above a threshold value of e.g. 38V, the protective circuit is not effective and there is an error.

3 FIG. 3 shows a schematic representation of an electronic power distributor 300 according to the disclosure. The electronic power distributor 300 corresponds to that in 1 electronic power distributor 100 described, but has three load channels 101, 102, 103 with appropriate wiring, and a bypass path 140.

The electrical bypass path 140 includes a p-type MOSFET transistor 341 which is connected in series with the electromechanical power switch 143 and is designed to switch off the electrical bypass path 140 in the event of a quiescent current violation.

The electrical bypass path 140 may have a sense resistor 342 connected in series with the electromechanical power switch 143 and the p-type MOSFET transistor 341 and configured to indicate a quiescent current violation via a current flow through the sense resistor 342 .

The electronic current distributor 300 can have a comparator 343, the inputs of which are connected in parallel to the measuring resistor 342, and which is designed to transmit a current flow through the measuring resistor 342 in the event of a quiescent current violation via a state change at the output of the comparator 343 to a control circuit 360, e.g. an electronic safety circuit. also known as eFASic, to display for diagnosis. This eFASic 360 can, for example, be a front end of a microcontroller, for example the µC 260 as in 2 described.

The functioning of the electronic current distributor 300 is explained below in accordance with FIG 3 described in more detail.

In the embodiment of 3 the series connection of a P-type MOSFET 341 is used to switch off the quiescent current bypass. This allows the quiescent current bypass to be switched off in the active phase. Furthermore, it allows channel-specific voltage isolation in the event of a quiescent current violation.

The channel-specific detection of quiescent current violations and their channel-specific disconnection from the battery voltage is explained below.

If the vehicle is in sleep mode, the EFASic 360 is switched off, so there is no quiescent current contribution. Disconnect the MOSFETs M1 to M3 (are high-impedance). The bypass 140 is switched through without quiescent current and supplies L1 to L3 (the three load channels 101, 102, 103) with voltage. For this, the gate of the P-type MOSFET 341 is pulled to ground in the bypass. The bimetallic switch (or electromechanical power switch) 143 takes over the short-circuit protection. Is there now a quiescent current violation because, for example, L2 or the second If the load channel 102 contains a µP that does not fall asleep and draws too high a current 320 (e.g. over 100mA) due to memory overflow, this leads to a rising edge of the comparator 343. The µC 260, which controls the EFASic 360, is woken up with this rising edge . The μC 260 now activates the EFASic 360. If M1 is now switched through, the current flow (1), 340 via the bypass 140 does not change. Likewise when M3 is switched through. If, on the other hand, M2 is switched on, the current through the bypass 140 goes to zero and the comparator 343 shows a falling edge.

With this, the software in the µC 260 can determine that the quiescent current violation originates from L2. Subsequently, when all channels M1 to M3 are switched through, the bypass 140 is separated via the P-type MOSFET 341 driven by the μC 260. M2 is then opened via the EFASic 360 (high resistance). This means that M2 is de-energized and the load that violates the quiescent current can be reset channel-specifically.

This feature is particularly useful after an Over The Air (OTA) upgrade because it allows dedicated resetting of the upgraded controller.

4 shows the current curve 401 and the voltage curve 402 of an exemplary activation of the electronic current distributor 300.

The time courses of the current 340 in the bypass path 140 and the gate voltage at the three MOSFETs M1, M2, M3 in the presence of a quiescent current violation are shown, as above 3 described.

If such a quiescent current violation occurs because, for example, L2 or the second load channel 102 contains a µP that does not go to sleep and draws too high a current 320 (e.g. over 100mA) due to memory overflow, this leads to a rising edge of the comparator 343 This rising edge wakes up the µC 260 that controls the EFASic 360. The μC 260 now activates the EFASic 360. If M1 is now switched through, as can be seen in the voltage curve 402, nothing changes in the current flow (1), 340 via the bypass 140, as can also be seen in the current curve 401. If M3 is switched through, as can be seen in the voltage curve 402, then nothing changes in the current flow (1), 340 via the bypass 140 either, as can also be seen in the current curve 401. If, on the other hand, M2 is switched through, as can be seen in the voltage curve 402, the current through the bypass 140 goes to zero, as can be seen in the current curve 401, and the comparator 343 shows a falling edge.

5 FIG. 5 shows a schematic representation of a method 500 for powering a plurality of load channels according to the disclosure.

The method 500 is used to power a plurality of load channels 101, 102 via an electronic power distributor 100, such as the above 1 until 3 described.

The electronic power distributor 100 has the following: a first electronic switch 110 with a first switchable current path 111 connected between a power supply terminal 150 and a first load channel 101 of the plurality of load channels, as per FIGS 1 until 3 described; an electrical bypass path 140, which is connected in parallel to the first switchable current path 111 of the first electronic switch 110 between the power supply terminal 150 and the first load channel 101, as in the above 1 until 3 described. The electrical bypass path 140 includes an electromechanical power switch 143, as described above 1 until 3 described.

The method 300 comprises the following steps: protecting 501 the first load channel 101 against a short circuit by switching off the first switchable current path 101 of the first electronic switch 110; and in the event of a short-circuit in the first load channel 101, dissipation 502 of a short-circuit power of the first load channel 101, which was commutated into the electrical bypass path 140 by switching off the first switchable current path 111, via an arc 144 in the electromechanical power switch 143.

Furthermore, a computer program with a program code for executing the method 400 in a controller, e.g. on an electronic security circuit or eFASic 360 as above in 3 shown or on a microcontroller 260 as above in 2 shown, are provided.

Reference List

100

electronic power distributor

101

first load channel

102

second load channel

150

Power connector or terminal

110

first electronic switch, first MOSFET

111

first switchable current path of the first electronic switch

112

first transil diode

113

first leakage inductance of the first load channel

120

second electronic switch, second MOSFET

121

second switchable current path of the second electronic switch

122

second transil diode

123

second leakage inductance of the second load channel

145

first diode

146

second diode

147

third diode

143

electromechanical power switch or circuit breaker

144

Arcing in the electromechanical circuit breaker

140

Bypass path or main path in the bypass path

141

first subpath in the bypass path

142

second subpath in bypass path

200

electronic power distributor

214

diagnostic capacitor

215

Diode to diagnostic capacitor

216

Resistance to diagnostic capacitor

260

Microcontroller with analog-to-digital converter (ADC)

300

electronic power distributor

360

electronic security circuit or eFASic

341

p-type MOSFET transistor

342

measuring resistor

343

comparator

401

Current course of a control of the electronic current distributor 300

402

Voltage curve of the control of the electronic current distributor 300

500

Method for powering a plurality of load channels

501

1. Process step

502

2. Process step

Claims (11)

Electronic power distributor (100) for supplying power to a plurality of load channels (101, 102), with: a first electronic switch (110) with a first switchable current path (111), which is connected between a power supply connection (150) and a first load channel (101) of the plurality of load channels (101, 102) and is designed to switch the first load channel (101 ) to protect against overcurrent; an electrical bypass path (140) which is connected in parallel to the first switchable current path (111) of the first electronic switch (110) between the power supply connection (150) and the first load channel (101), wherein the electrical bypass path (140) has an electromechanical circuit breaker (143) which is designed, in the event of a short circuit in the first load channel (101), to switch off the first switchable current path (111) into the electrical bypass path (140 ) to dissipate commutated short-circuit power via an arc (144) in the electromechanical circuit breaker (143). Electronic current distributor (100) after claim 1 , wherein the electromechanical power switch (143) has a bimetallic relay which is designed to convert thermal heating due to the short-circuit power into a mechanical movement for opening a contact of the bimetallic relay. Electronic current distributor (100) after claim 1 or 2 , wherein the electromechanical circuit breaker (143) is designed to limit an overvoltage occurring in the short circuit of the first load channel (101) to a voltage of the arc (144). Electronic power distributor (100) according to any one of the preceding claims, with: a first transil diode (112) connected in parallel to the first switchable current path (111) of the first electronic switch (110) and in parallel to the electrical bypass path (140) in the reverse direction between the power supply terminal (150) and the first load channel ( 101) is switched on. Electronic current distributor (100) after claim 4 , wherein the first Transil diode (112) is designed to reduce an overvoltage pulse occurring when the arc (144) breaks off in the electromechanical circuit breaker (143). Electronic current distributor (100) after claim 4 or 5 , where the first transil diode (112) is designed to absorb part of the short-circuit power when the first load channel (101) is short-circuited until a leakage inductance (113) of the electrical bypass path (140) is overcome and the short-circuit power via the arc (144) in the electromechanical power switch ( 143) is dismantled. Electronic current distributor (100) according to one of Claims 4 until 6 , wherein the first Transil diode (112) is designed to absorb and reduce at least part of the short-circuit power when the electromechanical circuit breaker (143) is damaged. Electronic current distributor (200) according to one of the preceding claims, with a diagnostic capacitor (214) which is connected in parallel to the first switchable current path (111) of the first electronic switch (110) and is designed to switch off the first switchable Current path (111) to detect the first switchable current path (111) applied voltage for a diagnosis by a microcontroller (260). Electronic power distributor (100) according to any one of the preceding claims, with: a second electronic switch (120) with a second switchable current path (121), which is connected between a second load channel (102) of the plurality of load channels (101, 102) and the power supply connection (150) and is designed to switch the second load channel (102 ) to protect against overcurrent, wherein the electrical bypass path (140) is also connected in parallel to the second switchable current path (121) of the second electronic switch (120) between the power supply connection (150) and the second load channel (102). Electronic current distributor (100) after claim 9 , wherein the electrical bypass path (140) has a branch, which branches the electrical bypass path (140) from a main path (140) to the power supply connection (150) into a first sub-path (141) to the first load channel (101) and has a second sub-path (142) branched to the second load channel (102), wherein the electromechanical power switch (143) is arranged in the main path (140) of the electrical bypass path. Method (500) for supplying power to a plurality of load channels (101, 102) via an electronic power distributor (100), the electronic power distributor (100) having the following: a first electronic switch (110) with a first switchable current path (111), which is connected between a power supply terminal (150) and a first load channel (101) of the plurality of load channels; an electrical bypass path (140) which is connected in parallel to the first switchable current path (111) of the first electronic switch (110) between the power supply connection (150) and the first load channel (101), the electrical bypass path (140 ) comprises an electromechanical power switch (143), the method (300) comprising: Securing (501) the first load channel (101) against a short circuit by switching off the first switchable current path (101) of the first electronic switch (110); and in the event of a short circuit in the first load channel (101), dissipation (502) of a short-circuit power of the first load channel (101) commutated by switching off the first switchable current path (111) into the electrical bypass path (140) via an arc (144) in the electromechanical circuit breaker (143).

Images