Short circuit error detection type lighting device for automotive floodlights

Abstract

To enable inspection of the operating state of a lighting device. A lighting device with short circuit error detection for automotive floodlights. The lighting device comprises a voltage input (SE) and a ground connection (ME) for connection to ground potential, and a power line (LS) containing a number of light sources (2) to be monitored, the light sources (2) being arranged to emit the light of the lighting device and being connected in series with one another in the power line (LS). The lighting device further comprises an auxiliary line (HS) containing a number of transistors (3) arranged in the auxiliary line (HS) and connected in series with one another. Each light source (2) of the power line (LS) is assigned one of the transistors (3), so that a monitoring pair (P1, P2, P3, P4) is formed, consisting of one light source (2) to be monitored and one transistor (3) assigned for monitoring it. Each transistor (3) is connected to the anode and cathode of the light source (2) in such a way that in normal operation the transistor (3) is switched into conduction by the voltage drop across the light source (2) and in the event of a short circuit of the light source (2) the transistor (3) and thus the auxiliary line (HS) are interrupted by the voltage drop caused by the short circuit. The lighting device further comprises an error detection device (6) connected to the auxiliary line (HS) which outputs an error signal (S F ) or activate an error routine (FR).

Description

[Technical field]

[0001] The present invention relates to a lighting device with short circuit error detection for a motor vehicle floodlight, comprising a voltage input and an earth connection for connection to earth potential, and a power line fed via said voltage input and containing a number of light sources to be monitored, said light sources being configured to emit light of the lighting device, said light sources being connected in series with one another in the power line. [Background technology]

[0002] In the past, in the automotive industry, it was customary to test lighting devices provided for floodlights (headlights, etc.) only for certain types of faults, namely those where the fault of one or more light sources leads to the interruption (disconnection) of an electrical connection that can be closed by the light sources in the normal state. It is also generally known that, for example, incandescent lamps, halogen lamps, xenon lamps, but also semiconductor elements, for example LEDs, typically go into a non-conducting state in the event of a fault, i.e. no current is conducted through the light source. If several light sources are connected in series, and one of the light sources fails, this leads to a non-conducting state of the light source, which in turn leads to the failure of the entire light source line, so that the light sources connected in series that are capable of operation also do not work.

[0003] However, a second type of error may also occur, namely a failure of the light source, which manifests itself in the form of a short circuit of (one) light source. This type of error was rare in the past, so that in the automotive industry no special measures were previously taken to detect short circuits of light sources. Previously, only the above type of error was checked by estimating the operating capability of the lighting device from the disappearance (interruption) of the current (due to an electrical non-conducting state caused by a failure of the light source). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] DE10 2008 008 217 A1 [Patent Document 2] US 10 178 734 B1 [Patent Document 3] AT 515 546 B1 [Patent Document 4] US 2018 / 049301 A1 Summary of the Invention [Problem to be solved by the invention]

[0005] It has been found that the occurrence of errors of the second type, i.e. short circuit errors, is increasing when using modern light sources. In this case, the light emission of the light source involved in the short circuit usually does not take place. However, other light sources located upstream or downstream in series can still be supplied with current. Such a fault leads to a negative (unfavorable) change in the light image emitted by the lighting device.

[0006] The object of the present invention is therefore to provide a lighting device which is as reliable in operation as possible, which makes it possible to check the operation or state of the lighting device and, if necessary, to introduce measures such as, for example, an error warning and / or an error routine. [Means for solving the problem]

[0007] According to a first aspect of the present invention, a short circuit error detection lighting device for an automotive floodlight is provided. The lighting device includes: a voltage input and an earth connection for connection to earth potential; a power line containing a plurality of light sources to be monitored and powered via said voltage input, said plurality being at least two, said light sources being configured to emit light of said lighting device, said light sources being connected in series with one another within said power line, Including, The lighting device further comprises: having an auxiliary line comprising a number of transistors arranged in the auxiliary line and connected in series with one another, each light source of the power line being assigned to one of the transistors, thus forming a monitoring pair consisting of one light source to be monitored and one transistor assigned to its monitoring, each transistor being connected to the anode and cathode of the light source in such a way that in normal operation the voltage drop at the light source switches the transistor into a conducting state, and in the event of a short circuit of the light source the voltage drop caused by the short circuit cuts off the transistor and thus the auxiliary line, The short circuit error detection type lighting device further includes an error detection device connected to the auxiliary line, the error detection device being configured to output an error signal or activate an error routine upon interruption of the auxiliary line. 、 the error detection device is configured to execute an error routine for automatically switching off the operation of the plurality of light sources upon detection of an error, for which purpose both the power line and the auxiliary line extend between the voltage input and the earth connection, and the error detection device is configured as a main switch, which is arranged in series with the power line and connected to the auxiliary line such that the main switch is electrically conducting when the auxiliary line is conducting and is electrically interrupting when the auxiliary line is interrupted. (Form 1) According to a second aspect of the present invention, a short circuit error detection lighting device for an automotive floodlight is provided. The lighting device includes: a voltage input and an earth connection for connection to earth potential; a power line containing a plurality of light sources to be monitored and powered via said voltage input, said plurality being at least two, said light sources being configured to emit light of said lighting device, said light sources being connected in series with one another within said power line, Including, The lighting device further comprises: having an auxiliary line comprising a number of transistors arranged in the auxiliary line and connected in series with one another, each light source of the power line being assigned to one of the transistors, thus forming a monitoring pair consisting of one light source to be monitored and one transistor assigned to its monitoring, each transistor being connected to the anode and cathode of the light source in such a way that in normal operation the voltage drop at the light source switches the transistor into a conducting state, and in the event of a short circuit of the light source the voltage drop caused by the short circuit cuts off the transistor and thus the auxiliary line, the short circuit error detection lighting device further comprising an error detection device connected to the auxiliary line, the error detection device configured to output an error signal or activate an error routine upon interruption of the auxiliary line; the transistors of the auxiliary line are configured as self-interrupting p-channel MOSFETs, an ohmic resistor is connected in series between each of the transistors, and in each monitoring pair the connection between the light source and the transistor is formed in such a way that the anode of the light source is connected to the source of the transistor and the cathode of the light source is connected to the gate of the transistor, the anode connections starting from the connection points between the light sources each comprise a diode which determines the power flow between the power line and the auxiliary line, the flow direction of the diode being oriented in the direction of the power line, the end of the auxiliary line facing the earth connection is connected to the earth connection via an auxiliary ohmic resistor and the end of the auxiliary line facing the voltage input is connected directly to the voltage input, a node is formed between the auxiliary line and the auxiliary ohmic resistor, the error detection device is electrically connected to this node and thereby detects a potential change of the node caused by interruption or conduction of the auxiliary line and outputs an error signal depending on this. The present invention 3 In view of the above, there is provided an automobile floodlight including the lighting device of the present invention (form 12 ). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A preferred embodiment of the invention is now presented. (Mode 1) See the first aspect of the present invention above. 。 ( form 2 )form1 In the lighting device according to the present invention, the transistors of the auxiliary line are configured as npn bipolar transistors, an ohmic resistor is connected in series between each of the transistors, and in each monitoring pair the connection between the light source and the transistor is formed in such a way that the anode of the light source is connected to the base of the transistor and the cathode of the light source is connected to the emitter of the transistor, each connection starting from a connection point between the light sources respectively comprises a diode which determines the flow of power between the power line and the auxiliary line, the direction of the flow of the diode in this respect being , supplement It is preferable that the main switch is oriented in the direction of the auxiliary line, and that the main switch is configured as a self-shutting p-channel MOSFET electrically connected at its source side to the voltage input, at its drain side to the power line, and at its gate side to the end of the auxiliary line on the voltage input side. (form 3 )form 2 In the lighting device according to the present invention, It is preferable that an end of the auxiliary line on the voltage input side is connected to the voltage input side via an auxiliary ohmic resistor, and an end of the auxiliary line on the earth side is connected to the earth connection part, a node is formed between the auxiliary line and the auxiliary ohmic resistor, and the node is connected to the gate of the main switch so that the potential of the node is changed so that the main switch is cut off when the auxiliary line is cut off, and the potential of the node is changed so that the main switch is turned on when the auxiliary line is turned on. (form 4 )form 1 In the lighting device according to the present invention, The transistors of the auxiliary lines are preferably configured as self-blocking MOSFET transistors. (form 5 )form 4 In the lighting device according to the present invention, The transistors of the auxiliary line are configured as self-shutting n-channel MOSFETs, an ohmic resistor is connected in series between each of the transistors, and in each monitoring pair, the connection between the light source and the transistor is such that the anode of the light source is directly connected to the gate of the transistor and the cathode of the light source is directly connected to the gate of the transistor. sauce The cathode connection paths starting from the connection points between the light sources are each provided with a diode that determines the flow of power between the power line and the auxiliary line, and the direction of the flow of the diode in this regard is , supplement It is preferable that the main switch is oriented in the direction of the auxiliary line, and that the main switch is configured as a self-shutting p-channel MOSFET electrically connected at its source side to the voltage input, at its drain side to the power line, and at its gate side to the end of the auxiliary line on the voltage input side. (form 6 )form 5 In the lighting device according to the present invention, It is preferable that an end of the auxiliary line on the voltage input side is connected to the voltage input side via an auxiliary ohmic resistor, and an end of the auxiliary line on the earth side is connected to the earth connection part, a node is formed between the auxiliary line and the auxiliary ohmic resistor, and the node is connected to the gate of the main switch so that the potential of the node is changed so that the main switch is cut off when the auxiliary line is cut off, and the potential of the node is changed so that the main switch is turned on when the auxiliary line is turned on. (form 7 )form 4 In the lighting device according to the present invention, It is preferred that the transistors of the auxiliary line are configured as self-shutting p-channel MOSFETs, that an ohmic resistor is connected in series between each of the transistors, and that in each monitoring pair the connection between the light source and the transistor is formed such that the anode of the light source is connected to the source of the transistor and the cathode of the light source is connected to the gate of the transistor, that the anode connection paths starting from the connection points between the light sources each include a diode that determines the flow of power between the power line and the auxiliary line, the flow direction of the diode being oriented in the direction of the power line, and that the main switch is configured as a self-shutting n-channel MOSFET electrically connected at its source to the earth connection, at its drain to the power line and at its gate to the end of the auxiliary line facing the earth connection. (form 8 )form 7 In the lighting device according to the present invention, It is preferable that the end of the auxiliary line on the earth connection side is connected to the earth connection side via an auxiliary ohmic resistor, and the end of the auxiliary line on the voltage input side is connected directly to the voltage input side, that a node is formed between the auxiliary line and the auxiliary ohmic resistor, and that the node is connected to the gate of the main switch so that the potential of the node is changed so that the main switch is cut off when the auxiliary line is cut off, and that the potential of the node is changed so that the main switch is turned on when the auxiliary line is turned on. (form 9 ) See the second aspect of the invention above. . (form 10 )form 9 In the lighting device according to the present invention, Preferably, the error detection device comprises an auxiliary transistor which is fully controlled depending on the potential of the node, the auxiliary transistor being connected via a temperature dependent resistor to an electrical control unit which detects the switch state of the auxiliary transistor and outputs an error signal depending thereon. (form 11 )form 9 In the lighting device according to the present invention, It is preferable that the error detection device includes an auxiliary transistor that is completely controlled depending on the potential of the node, and a binary error signal is output according to the switch state of the auxiliary transistor. (form 12 ) The present invention 3 See viewpoint.

[0009] The above object is achieved by a lighting device of the type mentioned at the outset, which according to the invention has an auxiliary line comprising a number of transistors arranged in said auxiliary line and connected in series with one another, wherein each light source of the power line is assigned one of the transistors, so that a monitoring pair is formed consisting of one light source to be monitored and one transistor assigned to its monitoring, each transistor being connected to the anode and the cathode of a light source in such a way that in normal operation the transistor is switched into conduction by the voltage drop at the light source, and in the event of a short circuit of the light source the transistor and thus the auxiliary line are interrupted by the voltage drop caused by the short circuit, and an error detection device is provided connected to the auxiliary line and configured to output an error signal and / or activate an error routine in the event of an interruption of the auxiliary line.

[0010] Thus, if a light source of the light source line is short-circuited due to an error, in the case of power supply via a current source, only the line voltage drops. However, by monitoring by means of transistors, a short-circuit error can be detected and possibly fed back, even though operation continues (thus avoiding a total failure or switching off of the power line). The light source can be, for example, an LED light source. The expression "for connection to earth potential" does not mean here that the relevant connection must necessarily be connected to earth potential. It is clear to the skilled person that only a corresponding voltage difference between the voltage input and the connection for connection to earth is required to electrically operate the lighting device. The reference potential itself is not important here in principle. This does not mean that the connection must be connected to earth, but only that there is a possibility of connection to earth. The number of light sources is, for example, at least two, three or four, but can also be significantly more and can be determined by the skilled person depending on the respective application.

[0011] In particular, the error detection device is configured to execute an error routine which automatically switches off the operation of the light source(s) when an error is detected, for which purpose both the power line and the auxiliary line extend between the voltage input and the earth connection, and the error detection device is configured as a main switch which is arranged in series with the power line and which can be connected to the auxiliary line such that the main switch is electrically conducting when the auxiliary line is conducting and is electrically disconnected when the auxiliary line is disconnected. In this way, it is possible to prevent a strong decrease in the light intensity of the lighting device, caused for example by a failure or shutdown of several light sources in the power line due to a short circuit of one light source, from going unnoticed and thus further falling below the statutory minimum requirements for the lighting device and thus increasing the danger for all road users.

[0012] Furthermore, the transistors of the auxiliary line are configured as npn bipolar transistors, an ohmic resistor is connected in series between the transistors, and in each monitoring pair, the connection between the light source and the transistor is made in such a way that the anode of the light source is connected to the base of the transistor and the cathode of the light source is connected to the emitter of the transistor, each connection path starting from the connection point between the light source and the light source is provided with a diode that defines the flow of power between the power line and the auxiliary line, the flow direction of the diode being directed toward the auxiliary line in the form of the transistor of the respective monitoring pair, and the main switch can be configured as a self-interrupting p-channel MOSFET electrically connected with its source side to the voltage input, its drain side to the power line and its gate side to the end (terminal) of the auxiliary line on the voltage input side. In this way, a reliable and cost-effectively replaceable short-circuit error detection lighting device is provided. In one developed form, the end of the auxiliary line on the voltage input side is connected to the voltage input side via an auxiliary ohmic resistor, and the end of the auxiliary line on the earth side is connected to an earth connection part, and a (single) node is formed between the auxiliary line and the auxiliary ohmic resistor, and the node can be connected to the gate of the main switch such that when the auxiliary line is cut off, the potential of the node is changed so that the main switch cuts off, and when the auxiliary line is conductive, the potential of the node is changed so that the main switch conducts.

[0013] Alternatively, the transistors of the auxiliary lines can be configured as self-shutting MOSFET transistors. In this case, in one development, the transistors of the auxiliary lines can be configured as self-shutting n-channel MOSFETs, with an ohmic resistor connected in series between them, in each monitoring pair the connection between the light source and the transistor is made in such a way that the anode of the light source is directly connected to the gate of the transistor and the cathode of the light source is connected to the drain of the transistor, the cathode connection paths starting from the connection points between the light sources respectively comprise a diode that determines the flow of power between the power line and the auxiliary line, the flow direction of the diode being oriented (connected) in the direction of the auxiliary line in the form of the transistor of the respective monitoring pair, and the main switch can be configured as a self-shutting p-channel MOSFET electrically connected with its source side to the voltage input, with its drain side to the power line and with its gate side to the end of the auxiliary line on the voltage input side.

[0014] Furthermore, the end of the auxiliary line on the voltage input side is connected to the voltage input via an auxiliary ohmic resistor, and the end of the auxiliary line on the earth side is connected to the earth connection, a node is formed between the auxiliary line and the auxiliary ohmic resistor, and the node can be connected to the gate of the main switch such that when the auxiliary line is cut off, the potential of the node is changed so that the main switch cuts off, and when the auxiliary line is conductive, the potential of the node is changed so that the main switch conducts.

[0015] Alternatively, the transistors of the auxiliary lines may be configured as self-shutting p-channel MOSFETs, with an ohmic resistor in series between each of them, the connection between the light source and the transistor in each monitoring pair is made in such a way that the anode of the light source is connected to the source of the transistor and the cathode of the light source is connected to the gate of the transistor, the anode connections starting from the connection points between the light sources each comprise a diode that determines the flow of power between the power line and the auxiliary line, the flow direction of the diode being oriented in the direction of said power line, and the main switch may be configured as a self-shutting n-channel MOSFET electrically connected with its source side to the earth connection, its drain side to the power line and its gate side to the end of the auxiliary line at the earth connection. The expression "anode connection" is here to be understood as a connection from the anode of each light source to each (corresponding) transistor. In one development, in this case, the end of the auxiliary line on the side of the earth connection is connected to the earth connection via an auxiliary ohmic resistor, and the end of the auxiliary line on the side of the voltage input is connected directly to the voltage input, a node is formed between the auxiliary line and the auxiliary ohmic resistor, and this node can be connected to the gate of the main switch such that when the auxiliary line is interrupted, the potential of the node is changed so that the main switch is interrupted, and when the auxiliary line is conductive, the potential of the node is changed so that the main switch is conductive.

[0016] Instead, the transistors of the auxiliary line are configured as self-interrupting p-channel MOSFETs, with an ohmic resistor connected in series between each of the transistors, the connection between the light source and the transistor in each monitoring pair is formed in such a way that the anode of the light source is connected to the source of the transistor and the cathode of the light source is connected to the gate of the transistor, the anode connection paths starting from the connection points between the light sources each comprise a diode that determines the flow of power between the power line and the auxiliary line, the flow direction of the diode being oriented (connected) in the direction of the power line, the end of the auxiliary line facing the earth connection is connected to the earth connection via an auxiliary ohmic resistor and the end of the auxiliary line facing the voltage input is connected directly to the voltage input, a node is formed between the auxiliary line and the auxiliary ohmic resistor, the error detection device is electrically connected to this node, whereby it is possible to detect a change in the potential of the node caused by interruption or conduction of the auxiliary line and to output an error signal depending on this.

[0017] In one development, the error detection device comprises an auxiliary transistor which is fully controlled depending on the potential of the node, which is connected via a temperature-dependent resistor to an electronic control unit, also called ECU, which is able to detect the switch state of the auxiliary transistor and output an error signal depending on it. The temperature-dependent resistor is in this case connected, for example, to a cooling body carrying the light source(s) and can thus be used at the same time for temperature-dependent control of the light source current. This temperature-dependent resistor is therefore often structurally present anyway for temperature measurement and is connected to the ECU. A second function can therefore be realised via the temperature-dependent resistor connected to the ECU by series (or alternatively parallel) connection with the auxiliary transistor.

[0018] In particular, the error detection device includes an auxiliary transistor that is fully controlled depending on the potential of the node, and a binary error signal can be output depending on the switch state of the auxiliary transistor.

[0019] Furthermore, the present invention relates to a vehicle floodlight (headlamp or the like) comprising the lighting device of the present invention.

[0020] The invention is explained in more detail below using illustrative but non-limiting examples shown in the drawings. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of an example of a first embodiment of the present invention. [Diagram 2] FIG. 5 is a schematic diagram of an example of a second embodiment of the present invention. [Diagram 3] FIG. 11 is a schematic diagram of an example of a third embodiment of the present invention. [Figure 4] FIG. 13 is a schematic diagram of an example of a fourth embodiment of the present invention. [Diagram 5] FIG. 13 is a schematic diagram of an example of a fifth embodiment of the present invention. [Figure 6] FIG. 13 is a schematic diagram of an example of a sixth embodiment of the present invention. EXAMPLES

[0022] In the following figures--unless otherwise specified--like drawing reference numbers represent like features.

[0023] 1 to 6 show an example of a short-circuit error detection lighting device 1 for a motor vehicle floodlight (headlight, etc.), comprising a voltage input SE and a (earth) connection ME for connection to earth potential. The lighting device 1 further comprises a power line LS which is powered via the voltage input SE and comprises a number of light sources 2 to be monitored, which are arranged to emit the light of the lighting device 1 and which are connected in series within the power line LS.

[0024] The lighting device 1 further comprises an auxiliary line HS, which comprises transistors 3 arranged therein and connected in series with one another. The light sources 2 of the power line LS are each assigned to one of the transistors. Thus, monitoring pairs P1, P2, P3 to P4 are each formed, each consisting of one light source 2 to be monitored and one transistor 3 assigned to the light source 2. For easier understanding, only the light sources and transistors of the first monitoring pair P1 are labeled with reference numerals.

[0025] In each monitoring pair, the transistor 3 is connected to the cathode and the anode of the associated light source 2 in such a way that a voltage drop at the light source 2 during normal operation switches the transistor 3 into a conducting state. On the other hand, if the light source 2 is short-circuited, the voltage drop caused by the short-circuit is used to cut off the transistor 3 and thus the current flow in the auxiliary line HS. Furthermore, an error detection device 6 is provided which is connected to the auxiliary line HS and which, in the event of a cut-off of the auxiliary line HS, generates an error signal S F (see Figs. 3 and 4) or executes (activates) an error routine FR (see other figures).

[0026] The embodiments according to figures 1, 2, 5 and 6 have in common that the error detection device 6 is configured to execute an error routine FR which automatically switches off the operation of the light sources 2 upon detection of an error. For this purpose, both the power line LS and the auxiliary line HS extend between the voltage input SE and the earth connection ME, and the error detection device 6 is configured as a main switch 4. This main switch 4 is arranged in series with the power line LS and is connected to the auxiliary line HS in such a way that the main switch 4 is electrically conductive when the auxiliary line HS is conductive and is electrically disconnected when the auxiliary line HS is disconnected.

[0027] In the embodiment of Fig. 5 and Fig. 6, the transistors 3 of the auxiliary line HS are further configured as npn bipolar transistors. An ohmic resistor 8 is connected in series between the transistors 3 respectively. In each of the monitoring pairs P1, P2, P3 to P4, the connection between the light source 2 and the transistor 3 is formed in such a way that the anode of the light source 2 is connected to the base of the transistor 3 and the cathode of the light source 2 is connected to the emitter of the transistor 3. Each connection starting from the connection point P between the light sources 2 and 2 respectively comprises a diode 7 which fixes the power flow between the power line LS and the auxiliary line HS. It is understood that the passing direction of the diode 7 is selected such that the power flow is accordingly fixed in one direction. For this reason, the flow direction of the diode 7 is directed in the direction of the auxiliary line HS, i.e. towards the transistor 3 of the respective monitoring pair P1, P2, P3, P4. The main switch 4 is configured as a self-interrupting p-channel MOSFET whose source side S4 is electrically connected to the voltage input section SE, whose drain side D4 is electrically connected to the power line LS, and whose gate side G4 is electrically connected to the end (terminal) of the auxiliary line HS on the voltage input side. Figure 6 differs from Figure 5 in the use of a so-called double diode 7', which is available at a particularly advantageous cost.

[0028] Furthermore, in the embodiment of Figures 5 and 6, the end of the auxiliary line HS on the voltage input side is connected to the voltage input section SE via an auxiliary ohmic resistor (device) 5, the end of the auxiliary line HS on the earth side is connected to the earth connection section ME, and a node K is formed between the auxiliary line HS and the auxiliary ohmic resistor 5, and the node K is connected to the gate G4 of the main switch 4 so that when the auxiliary line HS is cut off, the potential of the node K is changed so that the main switch 4 is cut off, and when the auxiliary line HS is conductive, the potential of the node K is changed so that the main switch 4 is conductive.

[0029] The embodiments of FIGS. 1 to 4 have in common that the transistor 3 of the auxiliary line HS is configured as a self-shutdown MOSFET transistor.

[0030] In the embodiment of FIG. 1, the transistors 3 of the auxiliary line HS are configured as self-shutting n-channel MOSFETs, with one ohmic resistor 8 connected in series between each of the transistors 3, and in each monitoring pair P1, P2, P3, P4, the connection between the light source 2 and the transistor 3 is such that the anode of the light source 2 is connected directly to the gate of the transistor 3 and the cathode of the light source 2 is connected directly to the gate of the transistor 3. sauce , the cathode connections starting from the connection point P between the light sources 2 each comprise a diode that fixes the power flow between the power line LS and the auxiliary line HS, the flow direction of the diode being oriented towards the auxiliary line HS in the form of a transistor 3 of the respective monitoring pair P1, P2, P3, P4, the main switch 4 being configured as a self-interrupting p-channel MOSFET electrically connected at its source to the voltage input SE, at its drain to the power line LS and at its gate to the voltage input end of the auxiliary line HS. 1, the voltage input end of the auxiliary line HS is connected to the voltage input SE via the auxiliary ohmic resistor 5, the earth end of the auxiliary line HS is connected to the earth connection ME, and a node K is formed between the auxiliary line HS and the auxiliary ohmic resistor 5, which is connected to the gate G4 of the main switch 4 in such a way that when the auxiliary line HS is disconnected, the potential of the node K is changed so that the main switch 4 disconnects, and when the auxiliary line HS is conductive, the potential of the node K is changed so that the main switch 4 conducts. This causes the power line LS to be automatically switched off as soon as a short circuit of the light source 2 is present (recognized).

[0031] In FIG. 2, the transistors 3 of the auxiliary line HS are configured as self-interrupting p-channel MOSFETs with an ohmic resistor in series between each of the transistors 3; in each monitoring pair P1, P2, P3, P4, the connection between the light source 2 and the transistor 3 is made such that the anode of the light source 2 is connected to the source of the transistor 3 and the cathode of the light source 2 is connected to the gate of the transistor 3; the anode connections starting from the connection point P between the light sources 2 and 2 each comprise a diode that fixes the power flow between the power line LS and the auxiliary line HS, with the flow direction of the diode being oriented in the direction of the power line LS; and the main switch 4 is configured as a self-interrupting n-channel MOSFET electrically connected at its source to the earth connection ME, at its drain to the power line LS and at its gate to the end of the auxiliary line HS that is connected to the earth connection. In detail, in this case, the end of the auxiliary line HS on the earth connection side is connected to the earth connection part ME via the auxiliary ohmic resistor 5, the end of the auxiliary line HS on the voltage input side is connected directly to the voltage input part SE, and a node K is formed between the auxiliary line HS and the auxiliary ohmic resistor 5, and the node K is connected to the gate G4 of the main switch 4 so that the potential (electric potential) of the node K is changed so that the main switch 4 is cut off when the auxiliary line HS is cut off, and the potential of the node K is changed so that the main switch 4 is turned on when the auxiliary line HS is turned on.

[0032] The embodiments of FIG. 3 and FIG. 4 have in common the following: the transistors 3 of the auxiliary line HS are configured as self-shutting p-channel MOSFETs, with an ohmic resistor in series between each of the transistors 3, in each monitoring pair P1, P2, P3, P4 the connection between the light source 2 and the transistor 3 is made in such a way that the anode of the light source 2 is connected to the source of the transistor 3 and the cathode of the light source 2 is connected to the gate of the transistor 3, the anode connection (path) starting from the connection point P between the light sources 2 and 2 respectively forms a power flow (power flow) between the power line LS and the auxiliary line HS, with its current direction oriented in the direction of the power line LS, its end on the earth connection side of the auxiliary line HS being connected to the earth connection ME via an auxiliary ohmic resistor 5 and its end on the voltage input side of the auxiliary line HS being connected directly to the voltage input SE, a node K being formed between the auxiliary line HS and the auxiliary ohmic resistor 5, an error detection device 6 being electrically connected to this node K, whereby it detects a change in potential of the node K caused by an interruption or conduction of the auxiliary line HS and outputs an error signal depending on this.

[0033] In the embodiment of FIG. 3, the error detection device further comprises an auxiliary transistor 10, which is fully controlled depending on the potential of the node, and which is connected to an electronic control unit ECU via a temperature-dependent resistor 9, which detects the switch state of the auxiliary transistor 10 and outputs an error signal depending on it. The temperature-dependent resistor 9 can for example come from (be a component of) an existing lighting device monitoring system, for example a temperature monitoring system. Typically, then, for example, the light sources 2 are fastened to a cooling body, the temperature of which is detected via a temperature-dependent resistor 9 connected to the ECU. Depending on the measured temperature, the current can be controlled. Then, for example, at temperatures above 110° C., the actual current is reduced with respect to the nominal (rated) current, and at a temperature of, for example, 130° C., only half of the nominal (rated) current is reached, so that further heating (temperature rise) can be avoided or at least delayed. Such a temperature monitoring device can be part of the lighting device, so that it can be coupled to short circuit detection by using a temperature-dependent resistor and an ECU already provided for temperature monitoring. If a short circuit is detected, the auxiliary transistor 10 is switched off, resulting in that a temperature-dependent resistor (e.g. in the form of an NTC) provided for temperature measurement of the circuit board or cooling body is used for a second purpose beyond temperature measurement, i.e. switched to an "open load" which can activate an error routine in the downstream ECU.

[0034] In FIG. 4, the error detection device 6 includes an auxiliary transistor 10 that is completely controlled depending on the potential of a node K, and outputs a binary error signal depending on the switch state of the auxiliary transistor 10.

[0035] The present invention further relates to an automobile floodlight (headlamp or the like) (not shown).

[0036] The present invention is not limited to the illustrated embodiments (examples) but is defined by the entire scope of protection of the (patent) claims. Moreover, the individual aspects of the invention or the embodiments (examples) can be adopted individually or in combination with each other. Possible drawing reference signs in the (patent) claims are exemplary and serve only to facilitate the readability of the (patent) claims without limiting the (patent) claims.

Claims

1. A short circuit error detection type lighting device for an automotive floodlight, comprising: The lighting device includes: a voltage input (SE) and an earth connection (ME) for connection to earth potential, a power line (LS) containing a plurality of light sources (2) to be monitored and powered via said voltage input (SE), said plurality being at least two, said plurality of light sources (2) being configured to emit the light of said lighting device, said plurality of light sources (2) being connected in series with one another within said power line (LS); Including, The lighting device further comprises: having an auxiliary line (HS) comprising a number of transistors (3) arranged in said auxiliary line (HS) and connected in series with one another, each light source (2) of said power line (LS) being assigned one of said transistors (3), thus forming a monitoring pair (P1, P2, P3, P4) consisting of one light source (2) to be monitored and one transistor (3) assigned to its monitoring, each transistor (3) being connected to the anode and cathode of said light source (2) in such a way that in normal operation, the voltage drop at said light source (2) switches said transistor (3) into a conducting state, and in the event of a short circuit of said light source (2), the voltage drop caused by the short circuit interrupts said transistor (3) and thus said auxiliary line (HS); The short circuit error detection type lighting device further includes an error detection device (6) connected to the auxiliary line (HS), the error detection device (6) generating an error signal (S Ｆ ) or activate an error routine (FR); the error detection device (6) is configured to execute an error routine (FR) for automatically switching off the operation of the plurality of light sources (2) upon detection of an error, for which purpose both the power line (LS) and the auxiliary line (HS) extend between the voltage input (SE) and the earth connection (ME), and the error detection device (6) is configured as a main switch (4), the main switch (4) being arranged in series with the power line (LS) and connected to the auxiliary line (HS) in such a way that the main switch (4) is electrically conductive when the auxiliary line (HS) is conductive and is electrically disconnected when the auxiliary line (HS) is disconnected. A lighting device comprising:

2. 2. The lighting device according to claim 1, The transistors (3) of the auxiliary line (HS) are configured as npn bipolar transistors, an ohmic resistor is connected in series between each of the transistors (3), and in each monitoring pair (P1, P2, P3, P4) the connection between the light source (2) and the transistor (3) is formed in such a way that the anode of the light source (2) is connected to the base of the transistor (3) and the cathode of the light source (2) is connected to the emitter of the transistor (3), the connection between the light source (2) and the light source (2) Each of the connection paths starting from the point (P) is provided with a diode (7) for determining the flow of power between the power line (LS) and the auxiliary line (HS), the flow direction of the diode (7) being directed toward the auxiliary line (HS), and the main switch (4) being configured as a self-interrupting p-channel MOSFET having a source side (S4) electrically connected to the voltage input section (SE), a drain side (D4) electrically connected to the power line (LS), and a gate side (G4) electrically connected to the end of the auxiliary line (HS) on the voltage input section side. A lighting device comprising:

3. 3. The lighting device according to claim 2, An end of the auxiliary line (HS) on the voltage input side is connected to the voltage input part (SE) via an auxiliary ohmic resistor (5), and an end of the auxiliary line (HS) on the earth side is connected to the earth connection part (ME); a node (K) is formed between the auxiliary line (HS) and the auxiliary ohmic resistor (5), and the node (K) is connected to a gate (G4) of the main switch (4) such that, when the auxiliary line (HS) is cut off, the potential of the node (K) is changed so that the main switch (4) is cut off, and, when the auxiliary line (HS) is conductive, the potential of the node (K) is changed so that the main switch (4) is conductive. A lighting device comprising:

4. 2. The lighting device according to claim 1, the transistor (3) of the auxiliary line (HS) is configured as a self-interrupting MOSFET transistor; A lighting device comprising:

5. 5. The lighting device according to claim 4, The transistors (3) of the auxiliary line (HS) are configured as self-interrupting n-channel MOSFETs; an ohmic resistor (8) is connected in series between each of the transistors (3); in each monitoring pair (P1, P2, P3, P4), the connection between the light source (2) and the transistor (3) is formed such that the anode of the light source (2) is directly connected to the gate of the transistor (3) and the cathode of the light source (2) is connected to the source of the transistor (3); 2) each of the cathode connection paths starting from a connection point (P) between the power line (LS) and the auxiliary line (HS) is provided with a diode that determines the flow of power between the power line (LS) and the auxiliary line (HS), the direction of the flow of the diode being oriented in the direction of the auxiliary line (HS), and the main switch (4) is configured as a self-interrupting p-channel MOSFET electrically connected at its source side to the voltage input section (SE), at its drain side to the power line (LS), and at its gate side to the end of the auxiliary line (HS) on the voltage input side. A lighting device comprising:

6. 6. The lighting device according to claim 5, An end of the auxiliary line (HS) on the voltage input side is connected to the voltage input part (SE) via an auxiliary ohmic resistor (5), and an end of the auxiliary line (HS) on the earth side is connected to the earth connection part (ME); a node (K) is formed between the auxiliary line (HS) and the auxiliary ohmic resistor (5), and the node (K) is connected to a gate (G4) of the main switch (4) such that, when the auxiliary line (HS) is cut off, the potential of the node (K) is changed so that the main switch (4) is cut off, and, when the auxiliary line (HS) is conductive, the potential of the node (K) is changed so that the main switch (4) is conductive. A lighting device comprising:

7. 5. The lighting device according to claim 4, the transistors (3) of the auxiliary line (HS) are configured as self-interrupting p-channel MOSFETs, an ohmic resistor is connected in series between each of the transistors (3), and in each monitoring pair, the connection between the light source (2) and the transistor (3) is formed in such a way that the anode of the light source (2) is connected to the source of the transistor (3) and the cathode of the light source (2) is connected to the gate of the transistor (3); the anode connection paths starting from the connection point (P) between the light sources (2) and (2) each include a diode that determines the flow of power between the power line (LS) and the auxiliary line (HS), the flow direction of the diode being oriented in the direction of the power line (LS); the main switch (4) is configured as a self-interrupting n-channel MOSFET electrically connected at its source to the earth connection (ME), at its drain to the power line (LS) and at its gate to the end of the auxiliary line (HS) on the earth connection side. A lighting device comprising:

8. 8. The lighting device according to claim 7, An end of the auxiliary line (HS) on the side of the earth connection part is connected to the earth connection part (ME) via an auxiliary ohmic resistor (5), and an end of the auxiliary line (HS) on the side of the voltage input part is directly connected to the voltage input part (SE); a node (K) is formed between the auxiliary line (HS) and the auxiliary ohmic resistor (5), and the node (K) is connected to a gate (G4) of the main switch (4) such that, when the auxiliary line (HS) is cut off, the potential of the node (K) is changed so that the main switch (4) is cut off, and, when the auxiliary line (HS) is conductive, the potential of the node (K) is changed so that the main switch (4) is conductive. A lighting device comprising:

9. A short circuit error detection type lighting device for an automotive floodlight, comprising: The lighting device includes: a voltage input (SE) and an earth connection (ME) for connection to earth potential, a power line (LS) containing a plurality of light sources (2) to be monitored and powered via said voltage input (SE), said plurality being at least two, said plurality of light sources (2) being configured to emit the light of said lighting device, said plurality of light sources (2) being connected in series with one another within said power line (LS); Including, The lighting device further comprises: having an auxiliary line (HS) comprising a number of transistors (3) arranged in said auxiliary line (HS) and connected in series with one another, each light source (2) of said power line (LS) being assigned one of said transistors (3), thus forming a monitoring pair (P1, P2, P3, P4) consisting of one light source (2) to be monitored and one transistor (3) assigned to its monitoring, each transistor (3) being connected to the anode and cathode of said light source (2) in such a way that in normal operation, the voltage drop at said light source (2) switches said transistor (3) into a conducting state, and in the event of a short circuit of said light source (2), the voltage drop caused by the short circuit interrupts said transistor (3) and thus said auxiliary line (HS); the short circuit error detection type lighting device further comprises an error detection device (6) connected to the auxiliary line (HS), the error detection device (6) being configured to output an error signal (SF) or activate an error routine (FR) when the auxiliary line is interrupted; the transistors (3) of the auxiliary line (HS) are configured as self-interrupting p-channel MOSFETs; an ohmic resistor is connected in series between each of the transistors (3); in each monitoring pair, the connection between the light source (2) and the transistor (3) is formed such that the anode of the light source (2) is connected to the source of the transistor (3) and the cathode of the light source (2) is connected to the gate of the transistor (3); the anode connection paths starting from the connection points (P) between the light sources (2) and (2) each include a diode that determines the flow of power between the power line (LS) and the auxiliary line (HS); the flow direction of the diode connected to the power line (LS) is oriented in the direction of the power line (LS); the end of the auxiliary line (HS) on the side of the earth connection is connected to the earth connection (ME) via an auxiliary ohmic resistor (5) and the end of the auxiliary line (HS) on the side of the voltage input is connected directly to the voltage input (SE); a node (K) is formed between the auxiliary line (HS) and the auxiliary ohmic resistor (5), and the error detection device (6) is electrically connected to this node (K) so as to detect a potential change of the node (K) caused by the interruption or conduction of the auxiliary line (HS) and output an error signal depending thereon. A lighting device comprising:

10. 10. The lighting device according to claim 9, The error detection device comprises an auxiliary transistor (10) which is fully controlled depending on the potential of the node (K), the auxiliary transistor (10) being connected via a temperature-dependent resistor (9) to an electronic control unit (ECU), the electronic control unit (ECU) detecting the switching state of the auxiliary transistor (10) and outputting an error signal depending thereon. A lighting device comprising:

11. 10. The lighting device according to claim 9, The error detection device (6) includes an auxiliary transistor (10) that is completely controlled depending on the potential of the node (K), and a binary error signal is output depending on the switch state of the auxiliary transistor (10). A lighting device comprising:

12. A vehicle floodlight comprising a lighting device according to any one of claims 1 to 11.

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