DE202018006097U1 - Illuminant with several semiconductor light sources for vehicle lights - Google Patents

Abstract

Light source (01) with a plurality of semiconductor light sources (02) for a vehicle lamp, comprising:
at least two semiconductor light source groups (03) each having a linear current source (04) and at least one semiconductor light source strand (05) connected thereto with at least two semiconductor light sources (02) arranged in series,
- Comparison means for comparing a vehicle electrical system voltage (U) with a voltage threshold (U _S ), and
connected to the comparison means switching means for switching between an arrangement in which at normal vehicle electrical system voltage higher than the voltage threshold (U _S ) at least two semiconductor light source groups (03) are arranged in series with a semiconductor light source group strand (06) to an arrangement in which, when the vehicle electrical system voltage is lower than the voltage threshold value (U _S ), the semiconductor light source groups (03) of the semiconductor light source group line (06) are connected in parallel.

Description

The invention relates to a luminous means provided for a vehicle luminaire with a plurality of semiconductor light sources, in particular LEDs and / or OLEDs, according to the preamble of claim 1.

It is well known that when the electric starter of an internal combustion engine of a vehicle is operated when the light is on, the light is darkened by the brief drop in the vehicle electrical system voltage at least at the beginning of the operation of the starter or briefly goes out.

The reason for this is that the vehicle electrical system voltage is typically between 11V and 15V during normal driving with the internal combustion engine running. At least during the operation of the starter, the vehicle electrical system voltage drops to values between typically 7V and 8V.

So far, this was of little concern, since in the past, the annealing except in marked driving school operation was done in stationary traffic and mostly to protect the onboard battery, the light was switched on only after the start.

In times ambient light-controlled light switch-on and start-stop automatisms, which shut down the internal combustion engine - at standstill as at a traffic light or the gas removal while driving - and start again when needed again, this is a Significant impairment of traffic safety, since the light functions, which are to be met when off and on the light of the vehicle lights installed on the vehicle, due to the brightness fluctuations difficult to recognize or can be misinterpreted, for example, when a bright brake light - and be it only briefly - darkens, although still braked, but just the internal combustion engine is started.

Due to their high efficiency in the conversion of electric current into light, semiconductor light sources are increasingly being used as light sources for vehicle use. The semiconductor light sources are hitherto predominantly inorganic, but in some cases organic light-emitting diodes.

Inorganic light emitting diodes consist of at least one light emitting diode semiconductor chip, short LED chip, and at least one, for example, molded by injection molding, the at least one LED chip completely or partially enveloping primary optics. Vehicle lights are also known in which pure LED chips are used without molded primary optics.

Through Hole Technology (THT), Surface Mounted Device (SMD) LEDs, and LEDs are known in which the LED chip is bonded directly to the illuminant carrier in COB (Chip On Board) technology.

THT LEDs, THT LEDs for short, are a well-known type of inorganic light-emitting diodes. They are also referred to as leaded light-emitting diodes, as they consist of an at least in a desired emission transparent encapsulation, e.g. in the form of an encapsulation or an encapsulation, which includes a LED chip with a first electrical connection, for example in the form of an anode terminal connecting bonding wire and connected to a second electrical connection, for example in the form of a cathode terminal, LED chip. From the encapsulation protrude only the designated as little legs wires of the first electrical connection and the second electrical connection as the anode and cathode terminals of the THT-LED. The second electrical connection embodied, for example, as a cathode connection can in this case be provided with a cup mentioned above, in which the LED chip is arranged. The bonding wire leads from the example executed as an anode terminal first connection from outside the cup coming to the LED chip.

SMD LEDs, SMD LEDs for short, are another well-known type of inorganic light-emitting diode. SMD LEDs consist of a leadframe with at least one mounting surface for at least one LED chip and electrical connection surfaces. The leadframe is partially encapsulated by a plastic body with at least one recess freeing at least one mounting surface. The electrical connection surfaces of the leadframe are also kept free as the electrical connections of the SMD LED for later surface mounting. The at least one LED chip is arranged and electrically contacted at the bottom of the at least one recess extending to the at least one mounting surface. In this case, the LED chip is arranged on a first portion of the leadframe connected to at least one first electrical connection area. A bonding wire connects the LED chip to a second portion of the leadframe, which in turn is connected to at least one second electrical pad. The reaching at its base to the mounting surface recess may be designed reflector-like. The walls of the recess form the above-mentioned primary reflector. Here, the walls can be coated reflective.

COB LEDs, COB LEDs for short, consist of an unhoused LED chip and a bonding wire to be arranged directly on a light carrier. The back side of the LED chip forms the first electrical connection of the COB LED. For electrical contacting, the LED chip on its rear side is directly connected to a first conductor track of a luminous means carrier, e.g. electrically connected by soldering or welding. The bonding wire forming the second electrical connection of the COB LED is likewise connected to a second conductor track of the illuminant carrier, e.g. electrically connected by soldering or welding.

For the sake of completeness, it should additionally be mentioned that other contacts, such as the so-called flip-chip structure are possible, in which the contact means of the LED chip are connected directly to a contacted substrate. In these cases, no bonding wire is used.

In the following, therefore, for the sake of simplicity, no distinction is made between inorganic light-emitting diode and LED chip and instead the term LED is used uniformly for both, unless explicitly stated otherwise. Outstanding properties of LEDs compared to other, conventional light sources of bulbs are a much longer life and a significantly higher light output with the same power consumption. In other words, at the same light intensity, LEDs have lower power consumption compared to other light sources. In this way, when using one or more LEDS as the light source of a light source, for example, in a vehicle lamp, the load of a provided for power supply electrical system of a vehicle can be reduced, along with savings in energy consumption of the vehicle. Furthermore, LEDs have a much longer life than other, for use in a vehicle lamp candidate light sources. Due to the longer service life, among other things, the lower failure rate increases the operational safety and, concomitantly, the quality of the vehicle lamp.

An organic light-emitting diode (OLED) is a luminous thin-film component made of organic semiconducting materials with at least one emitter layer enclosed between electrically conductive, for example metallic layers for anode and cathode. The thickness or, in other words, the thickness of the layers is on the order of about 100 nm. Typically, it is 100 nm to 500 nm, depending on the structure. For protection against water, oxygen and for protection against other environmental influences, such as scratch damage and / or pressure loading OLEDs typically encapsulated with an inorganic material, especially glass. Although there are efforts to replace the glass with plastic, but in particular to meet, for example, the service life requirement of vehicle lights and their light sources with several 1000 hours sufficiently well not crowned by the desired success, because the tightness of the alternative materials for the encapsulation not is sufficiently good enough.

In contrast to inorganic light-emitting diodes, OLEDs do not require monocrystalline materials. Compared to LEDs, OLEDs can therefore be produced using inexpensive thin-film technology. OLEDs thereby make it possible to produce flat light sources which on the one hand have a very thin appearance and, on the other hand, have a particularly homogeneous appearance when used as a luminous surface visible through the lens of a vehicle lamp.

LEDs have a forward voltage, which makes it possible to arrange a plurality of LEDs in series or in series with an LED string and to apply the vehicle electrical system voltage as a supply voltage to the LED string at normal, prevailing in driving operation with the engine running vehicle electrical system voltage. Due to the higher forward voltage of OLEDs, that number of OLEDs which can be connected in series or in series with an OLED strand and which, while maintaining the light emission, makes it possible to apply the vehicle electrical system voltage prevailing when the internal combustion engine is running as the supply voltage to an OLED line with LEDs.

In addition to the described advantages, however, semiconductor light sources have the disadvantage that they do not tend to darken just like conventional light sources due to their functional principle and short reaction time, for example when the electric starter of an internal combustion engine of a vehicle is actuated when the light is on and the vehicle electrical system voltage therefore drops when the voltage applied to them falls below their respective forward voltage or when the vehicle electrical system voltage drops below a minimum supply voltage resulting from the sum of the forward voltages of the semiconductor light sources connected in series with a semiconductor light source train.

This exacerbates the initially described impairment of traffic safety by the Increasing replacement predominantly reaction-bearing, conventional light sources, such as light bulbs, halogen lamps and gas discharge lamps by semiconductor light sources.

In order to counteract this, the number of semiconductor light sources arranged in series with a semiconductor light source strand has been reduced to a number in which the maintenance of an electrical voltage at each of the semiconductor light source voltage is still maintained in the case of, for example, the operation of an electric starter of an internal combustion engine. Strand arranged semiconductor light source is ensured above the forward voltage. To protect against destruction or premature aging by overvoltage in normal, prevailing in the running operation with the internal combustion engine board voltage, semiconductor light sources, such as the mentioned LEDs and / or OLEDs, and / or semiconductor light source strands, such as the mentioned LED strands and / or OLED strands, moreover, hitherto installed in series with current limiters or similarly acting circuit elements, which reduce the normal vehicle electrical system voltage to a supply voltage in which the series-connected semiconductor light sources are not damaged, and which with lowered vehicle electrical system voltage nor the operation of the series allow switched semiconductor light sources.

The disadvantage of this is that by this optimization to a lowered vehicle electrical system voltage during the majority of driving, during which not a lowered, but normal board voltage prevails, a not inconsiderable part of the electrical system for the operation of legally required for the fulfillment of road traffic light functions provided semiconductor optical sources removed and otherwise available again to be provided electrical energy is lost as power loss unused.

By US 2007/108843 A1 is a power supply of series-connected semiconductor light sources of a vehicle intended for light bulbs known. The power supply includes a constant current source and a bypass switch in parallel with each semiconductor light source and / or each pair of series-connected semiconductor light sources and / or each group of series-connected semiconductor light sources. By opening and closing the respective bypass switch, the individual semiconductor light sources and / or pairs of semiconductor light sources connected in series and / or groups of semiconductor light sources connected in series can be individually illuminated or switched off as required. An electrical control of the bypass switch detects faults of one or more semiconductor light sources and switches off faulty semiconductor light sources by bridging. The electrical control can illuminate redundant semiconductor light sources to replace faulty semiconductor light sources. By pulse width modulation of the opening and closing of the bypass switch, the electrical control can dim one or more semiconductor light sources as needed. During the bypass in certain operating conditions, as would prevail in a vehicle application, for example, with lowered vehicle electrical system voltage, at least a portion of the LEDs remains dark.

This is not a satisfactory solution to the described impairment of traffic safety, because a part of the semiconductor light sources of a provided for fulfilling a light function in a vehicle lamp bulb with multiple semiconductor light sources remain dark as light sources with lowered board voltage and thus the light emission of the light source is reduced overall and at least in individual Spaces of the entire, to be covered jointly by all semiconductor light sources solid angle range is absent. An additional disadvantage also results from the fact that during operation of the lamp with lowered vehicle electrical system voltage, a part of the LEDs remain directly recognizable dark. Furthermore, this represents a waste of resources, at least when the vehicle electrical system voltage is lowered, since a part of the semiconductor light sources installed in the lighting device is not used as light sources.

By US 2013/207548 A1 is a light source with multiple light sources designed as LEDs known. In order to adapt to very different supply voltages, the lighting means may have a current limiter arranged in series with the LEDs, accompanied by the disadvantage of high power loss at high supply voltage. Alternatively or additionally, the lighting means may comprise a microcontroller and activation switches arranged in series with the LEDs and / or bypass switches arranged parallel to one or more of the LEDs. Outputs of the microcontroller open and close the switches to turn the LEDs on when the power supply voltage by closing the activation switch all shut down at too high supply voltage by opening the activation switch or to bridge at low supply voltage by closing the bypass switch part of the LEDs. For this purpose, the microcontroller can compare a detected supply voltage and / or a supply current intensity and / or a temperature with one or more threshold values and, depending thereon, completely disconnect the LEDs from the supply voltage or bypass a portion of the LEDs or switch on all the LEDs.

In addition to the mentioned disadvantage of high power loss when using a series-connected current limiter, this is not a satisfactory solution of the described impairment of traffic safety, because a part of the LEDs of a provided for fulfilling a light function in a vehicle lamp bulb with multiple LEDs as light sources with lowered vehicle electrical system voltage dark remain and thus the light emission of the lamp is reduced overall and at least in individual spatial directions of the entire, to be covered by all LEDs together solid angle range is absent. An additional disadvantage also results from the fact that during operation of the lamp with lowered vehicle electrical system voltage, a part of the LEDs remain directly recognizable dark. Moreover, instead of a satisfactory solution, this represents a not inconsiderable waste of resources, since at least in some areas of the supply voltage at least part of the LEDs installed in the light source as light sources is unused.

An alternative is elaborate polarity reversal protection circuits and a selection of the forward voltages of the LEDs in order to operate just three LEDs in series with lowered vehicle electrical system voltage. However, this is associated with additional costs or limited availability of suitable LEDs.

• - die Halbleiterlichtquellen der Gruppe in zwei Untergruppen zu jeweils mindestens einer Halbleiterlichtquelle aufgeteilt sind,
• - die nach der Aufteilung jeweils einer Untergruppe zugeordneten Halbleiterlichtquellen jeweils in Serie zu je einem Halbleiterlichtquellen-Unterstrang elektrisch verschaltet sind, und
• - die beiden Halbleiterlichtquellen-Unterstränge parallel verschaltet sind. Das Leuchtmittel umfasst Mittel zur Überwachung und Erfassung einer Bordnetzspannung sowie zum Vergleich der überwachten Spannung mit einem Spannungs-Schwellenwert. Das Leuchtmittel umfasst außerdem Mittel zur Umschaltung zwischen den bei normaler Spannung höher als der Spannungs-Schwellenwert in Serie zu einem Halbleiterlichtquellen-Strang angeordneten Halbleiterlichtquellen der Gruppe zu einer Anordnung, bei der:
• - bei abgesenkter Spannung niedriger als der Spannungs-Schwellenwert die Halbleiterlichtquellen der Gruppe in zwei Untergruppen zu jeweils mindestens einer Halbleiterlichtquelle aufgeteilt sind,
• - die jeweils einer Untergruppe zugeordneten Halbleiterlichtquellen jeweils in Serie zu je einem Halbleiterlichtquellen-Unterstrang verschaltet sind, und
• - die beiden Halbleiterlichtquellen-Unterstränge parallel verschaltet sind.

By EP 3 193 563 A1 are known a method for operating a light provided for a vehicle lamp with a group of at least two semiconductor light sources, as well as a suitable for performing the method light source with a group of at least two semiconductor light sources. The method provides a switchover between the semiconductor light sources of the group which are connected at a normal vehicle supply voltage higher than a voltage threshold in series with a semiconductor light source train to form an arrangement in which, with the vehicle electrical system voltage lowered, lower than the voltage threshold value:

• the semiconductor light sources of the group are subdivided into two subgroups, each with at least one semiconductor light source,
• - The after the division of a respective subgroup associated semiconductor light sources are each electrically connected in series with one semiconductor light source sub-string, and
• - The two semiconductor light source sub-strands are connected in parallel. The light-emitting means comprises means for monitoring and detecting a vehicle electrical system voltage and for comparing the monitored voltage with a voltage threshold. The luminous means further comprises means for switching between the semiconductor light sources of the group which are arranged at normal voltage higher than the voltage threshold in series with a semiconductor light source strand to form an arrangement in which:
• when the voltage is lower than the voltage threshold, the semiconductor light sources of the group are divided into two subgroups, each with at least one semiconductor light source,
• - Each of a subgroup associated semiconductor light sources are each connected in series with one semiconductor light source sub-string, and
• - The two semiconductor light source sub-strands are connected in parallel.

This method and this illuminant are practical for a few LEDs in which no failure must be detected and have the advantage of a manageable effort for the circuit structure. The disadvantage of this is that due to the high efficiency of semiconductor light sources associated with their low power consumption is not possible to detect a failure of one or more semiconductor light sources by means of an on-board controller, for example, to indicate the failure and / or replacement at the next inspection date the driver.

By DE 10 2006 024 607 A1 a luminous system with two branches is known, in each of which a light emitting diode array, a current source and / or current sink and a switching device are connected in series or switchable. The first branch is switched or switchable parallel to the second branch. A bridge branch is designed for switchable connection of the first branch to the second branch such that the first light-emitting diode arrangement is connected or switchable in series with the second light-emitting diode arrangement.

The disadvantage of this is that the lighting system comprises no means which, depending on predetermined or predetermined criteria, an automatic switching of the lighting system from the arrangement of the first branch parallel to the second branch to the arrangement of the first branch and the second branch in series and back again cause. Only such means allow a resource-saving use of such a lighting system in a vehicle lamp.

An object of the invention is to develop a light source with a plurality of semiconductor light sources, which provided for a vehicle lamp low power loss while high resource utilization allows a high contribution to traffic safety.

The object is solved by the features of the independent claim. Advantageous embodiments are set forth in the claims, the drawings and the following description, including those associated with the drawings.

The invention provides to increase the efficiency associated with the possibility of detecting the failure of one or more semiconductor light sources, such as LEDs before, two or more circuit blocks, each consisting of a linear current source or an LED driver and a connected thereto and supplied with power semiconductor light sources -Strang of two or more series-connected semiconductor light sources, in particular LEDs, parallel with lowered vehicle electrical system voltage and at short also called nominal voltage normal vehicle electrical system voltage in series.

Therefore, a linear current source, also referred to as an LED driver, is used for at least two, advantageously for a number of, series-connected semiconductor light sources, such as LEDs, which number of semiconductor light sources, such as LEDs with lowered, for example minimal on-board voltage, in series with the LED. Driver can be supplied.

The at least two series-arranged semiconductor light sources are referred to in the context of the invention as a semiconductor light source strand.

In contrast, a semiconductor light source group, also referred to as a circuit block or a short block, in the context of the invention designates a linear current source having a semiconductor light source strand connected thereto or a linear current source having a plurality of semiconductor light source strands connected in parallel thereto. A semiconductor light source group hereinafter comprises the linear current source and at least one semiconductor light source strand connected thereto.

When briefly also referred to as nominal voltage normal vehicle electrical system voltage, for example when the generator is running, results from the previously described arrangement of two supplied by a linear power source or connected to this and arranged in series semiconductor light sources without further measures, a poor efficiency.

In order to counteract this, the invention also provides for switching at least two semiconductor light source groups in series at nominal voltage, which increases the efficiency.

When the vehicle electrical system voltage is lowered, however, the invention provides for the at least two semiconductor light source groups to be switched in parallel, whereby all the semiconductor light sources of the light source are operated when the vehicle electrical system voltage is lowered.

By virtue of the fact that each semiconductor light source group comprises a linear current source, it is possible for the failure of individual semiconductor light sources, such as LEDs of the luminous means, to be detected.

The invention thus eliminates the disadvantages of the prior art by a variable interconnection of the circuit blocks from parallel to serial and vice versa.

The invention is realized by a lamp provided for a vehicle lamp with a plurality of semiconductor light sources.

The luminous means comprises at least two semiconductor light source groups, each consisting of a linear current source and at least one semiconductor light source strand connected to the linear current source, comprising at least two semiconductor light sources arranged in series.

For each semiconductor light source group, a plurality of semiconductor light source strands can be connected in parallel to one another to the linear current source of the semiconductor light source group and can be supplied or supplied with power by the latter.

In addition, the luminous means comprises comparison means for comparing a vehicle power supply voltage that supplies the power supply of the luminous means with a voltage threshold value.

In addition, the lighting means comprises switching means connected to the comparison means for switching between an arrangement in which, with normal vehicle electrical system voltage higher than the voltage threshold, two or more semiconductor light source groups each comprising a linear current source are arranged in series with a semiconductor light source group train Arrangement in which, when the vehicle electrical system voltage is lower than the voltage threshold value, the respective semiconductor light source groups of the semiconductor light source group string which each comprise a linear current source are connected in parallel.

A linear current source is a current source whose characteristic curve reflects the current emitted by it above the voltage applied at its connection points in a current-voltage diagram of a line with a negative gradient. She can be in Substitute circuit diagram as an ideal power source with an internal resistance in parallel circuit will be described.

The number of semiconductor light sources per semiconductor light source strand can correspond in each case to one of the number of semiconductor light sources which can be operated in series with minimal prevailing vehicle supply voltage.

It can be seen that the invention provides for the object to also form groups of semiconductor light sources, such as LEDs and / or OLEDs, referred to as blocks, and to interconnect these with a respective linear current source, for example an LED driver, so that the Semiconductor light sources of the blocks operate at minimum voltage. Thus, these blocks can be operated in parallel with minimum vehicle electrical system voltage. At rated voltage, the blocks are switched in series. Thus all functions of the linear current sources, such as a failure detection of individual semiconductor light sources of the blocks are available.

In vehicle applications, usually only LED strings with two LEDs are feasible because the minimum prevailing vehicle electrical system voltage is about 7V. However, the normal vehicle electrical system voltage prevailing during driving is 13.5V and thus makes it possible to connect four LEDs in series.

The invention allows the switching of, for example, two LED blocks with LED strings with two LEDs in series. By assigning one linear current source to each block, the full range of functions of the LED driver is available, such as failure detection.

Advantages are provided hereafter by maintaining the detection capability of the failure of individual or multiple semiconductor light sources, in particular LEDs, by means of the LED driver, along with a high efficiency and low power dissipation and with avoiding flickering realized by semiconductor light sources such as LEDs light function in vehicles with start-stop system.

Further advantages over the prior art are that standard components can be used. These can be optimally thermally operated, for example in order to reduce the required board area or to save cooling plates.

For example, the invention allows the use of standard components for powering semiconductor light sources, such as LEDs.

Additional advantages include a simple way of scaling and opening the possibility to use the functions that are included in an LED driver, in particular the failure detection.

For example, the invention allows for easy scalability due to the modular construction of circuit blocks.

The comparator means for comparing a power supply voltage of the illuminant with a voltage threshold value is, for example, a Schmitt circuit, also known as a so-called Schmitt trigger, advantageously with hysteresis, particularly advantageously with adjustable hysteresis.

The hysteresis avoids undesired frequent switching back and forth with fluctuating around the voltage threshold around the vehicle electrical system voltage.

The invention makes it possible to carry out a method for operating a luminous means provided for a vehicle luminaire with a plurality of semiconductor light sources.

The method provides, at least two semiconductor light source groups each having at least one semiconductor light source strand of at least two series-arranged semiconductor light sources, but at most each one of the number of semiconductor light sources operable at minimum prevailing vehicle voltage in number corresponding number of semiconductor light sources corresponding number of semiconductor light sources arranged in series form.

In order to reduce the electrical control performance and thus also the electrical power loss, it makes sense to connect as many semiconductor light sources as possible in series, wherein the number of the maximum electrically arranged in a row semiconductor light sources, such as LEDs or OLEDs, is predetermined by the minimal prevailing vehicle electrical system voltage ,

By arranging in each case a number of semiconductor light sources per semiconductor light source group which can be operated in series at a minimal prevailing vehicle supply voltage, the operation of the semiconductor light sources within the semiconductor light source groups can be ensured even when the vehicle electrical system voltage is lowered.

Each semiconductor light source group may include one or more semiconductor light source strands arranged in parallel in this case within the semiconductor light source group.

The method also provides for providing each semiconductor light source group with a linear current source, also referred to as a semiconductor light source driver, to which the at least one semiconductor light source strand of the corresponding semiconductor light source group is connected.

As a result, a failure of one or more semiconductor light sources per semiconductor light source group can be detected.

In addition, the method provides detection of the vehicle electrical system voltage of a vehicle equipped with the vehicle lamp and the comparison of the detected vehicle electrical system voltage with a voltage threshold.

The method now envisages, in the case of a normal vehicle electrical system voltage higher than the voltage threshold value, to connect two or more semiconductor light source groups, each comprising a linear current source, in series with a semiconductor light source group line.

The method also provides a switching between the normal vehicle electrical system voltage higher than the voltage threshold in series with a semiconductor light source group strand interconnected semiconductor light source groups to an arrangement in which when the vehicle electrical system voltage lower than the voltage threshold each one Linear power source comprising semiconductor light source groups of the semiconductor light source group strand are connected in parallel.

The arrangement of a linear current source per semiconductor light source group as well as the limitation of an arrangement within each semiconductor light source group in each case one of the number of semiconductor light sources operable in series with minimal prevailing vehicle supply voltage means a number of semiconductor light sources in series with a semiconductor light source strand all semiconductor light sources of a semiconductor light source group met with minimal prevailing vehicle electrical system voltage.

By connecting two or more semiconductor light source groups in series to a semiconductor light source group strand at normal vehicle electrical system voltage higher than the voltage threshold resulting in normal driving conditions a reduction in power loss compared to maintaining the lowered vehicle electrical system voltage lower than the voltage Threshold prevailing arrangement above the voltage threshold.

The lighting means may comprise individual or a combination of the features described above and / or subsequently in connection with the method, just as the method may comprise and / or implement individual or a combination of a plurality of features previously and / or subsequently described in connection with the lighting means.

Both the illuminant and, alternatively or additionally, the method may alternatively or additionally comprise one or a combination of several in the context of the prior art and / or in one or more of the documents mentioned in the prior art and / or in the following description have the features described in the drawings embodiments.

Additional advantages over the prior art that go beyond the complete solution of the problem set and / or the advantages mentioned above for the individual features are listed below.

• 1 eine Schaltungsanordnung eines erfindungsgemäßen Leuchtmittels mit parallel angeordneten LED-Treibersträngen bei abgesenkter Bordnetzspannung.
• 2 eine Schaltungsanordnung eines erfindungsgemäßen Leuchtmittels mit in Serie angeordneten LED-Treibersträngen bei normaler Bordnetzspannung.
• 3 ein Ablaufdiagramm eines Verfahrens zum Betrieb eines für eine Fahrzeugleuchte vorgesehenen Leuchtmittels mit mehreren Halbleiterlichtquellen.
• 4 ein Ausführungsbeispiel eines Schaltungsaufbaus eines eine Linearstromquelle verwirklichenden Treiberbausteins in 4 a), der in 4 b) als ein eine Halbleiterlichtquellen-Gruppe bildendes Teil zusammengefasst ist.
• 5 ein Ausführungsbeispiel eines Schaltungsaufbaus eines Leuchtmittels mit zwei durch anhand von Schaltern verwirklichte Schaltungsmittel wahlweise parallel oder in Serie verbindbaren Halbleiterlichtquellen-Gruppen nebst optionaler Ausfallerkennung.
• 6 ein erstes Ausführungsbeispiel eines eine Schmitt-Schaltung zumindest als ein Teil von Vergleichsmitteln zum Vergleich einer Bordnetzspannung eines die Stromversorgung des Leuchtmittels besorgenden Bordnetzes eines mit einer entsprechenden Fahrzeugleuchte ausgestatteten Fahrzeugs mit einem Spannungs-Schwellenwert verwirklichenden, diskreten Schaltungsaufbaus.
• 7 ein zweites Ausführungsbeispiel eines eine Schmitt-Schaltung zumindest als ein Teil von Vergleichsmitteln zum Vergleich einer Bordnetzspannung eines die Stromversorgung des Leuchtmittels besorgenden Bordnetzes eines mit einer entsprechenden Fahrzeugleuchte ausgestatteten Fahrzeugs mit einem Spannungs-Schwellenwert verwirklichenden, diskreten Schaltungsaufbaus.
• 8 ein drittes Ausführungsbeispiel eines eine Schmitt-Schaltung zumindest als ein Teil von Vergleichsmitteln zum Vergleich einer Bordnetzspannung eines die Stromversorgung des Leuchtmittels besorgenden Bordnetzes eines mit einer entsprechenden Fahrzeugleuchte ausgestatteten Fahrzeugs mit einem Spannungs-Schwellenwert verwirklichenden Schaltungsaufbaus mit Operationsverstärker.
• 9 ein Schaltbild eines integrierten Elektronikbauteils, welches eine Schmitt-Schaltung zumindest als ein Teil von Vergleichsmitteln zum Vergleich einer Bordnetzspannung eines die Stromversorgung des Leuchtmittels besorgenden Bordnetzes eines mit einer entsprechenden Fahrzeugleuchte ausgestatteten Fahrzeugs mit einem Spannungs-Schwellenwert verwirklicht, wobei das in 9 a) dargestellte Schaltbild ein integriertes Elektronikbauteil zeigt, das eine Schmitt-Schaltung verwirklicht, die einen invertierenden Schmitt-Trigger bildet, und das in 9 b) dargestellte Schaltbild ein integriertes Elektronikbauteil zeigt, welches eine Schmitt-Schaltung verwirklicht, die einen nicht-invertierenden Schmitt-Trigger bildet.
• 10 ein Schaltspannungs-Eingangsspannungs-Diagramm einer Schmitt-Schaltung mit häufiges Hin- und Herschalten zwischen zwei Ausgangsspannungen U_{a max} und U_{a min} bei um einen Spannungs-Schwellenwert U_S hin und her schwankender Eingangsspannung U_e vermeidender Hysterese, bei dem die Ausgangsspannungen U_a über der Eingangsspannung U_e aufgetragen ist.

The invention will be explained in more detail with reference to embodiments shown in the drawings. The proportions of the individual elements to one another in the figures do not always correspond to the actual size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration. For identical or equivalent elements of the invention, identical reference numerals are used. Furthermore, for the sake of clarity, only reference symbols are shown in the individual figures, which are required for the description of the respective figure. The illustrated embodiments are only examples of how the invention may be configured and are not an exhaustive limitation. In a schematic representation:

• 1 a circuit arrangement of a luminous means according to the invention with parallel LED driver strings with lowered vehicle electrical system voltage.
• 2 a circuit arrangement of a luminous means according to the invention with arranged in series LED driver strings at normal vehicle electrical system voltage.
• 3 a flowchart of a method for operating a light provided for a vehicle lamp with a plurality of semiconductor light sources.
• 4 an embodiment of a circuit structure of a linear current source realize a driver module in 4 a) who in 4 b) is summarized as a semiconductor light source group forming part.
• 5 an embodiment of a circuit structure of a light source with two realized by means of switches circuit means optionally parallel or in series connectable semiconductor light source groups, together with optional failure detection.
• 6 a first embodiment of a Schmitt circuit at least as a part of comparison means for comparing a vehicle electrical system voltage of the vehicle power supply of the illuminating vehicle supplying a vehicle equipped with a corresponding vehicle lamp with a voltage threshold realizing, discrete circuit structure.
• 7 a second embodiment of a Schmitt circuit at least as a part of comparison means for comparing a vehicle electrical system voltage of the vehicle power supply of the illuminating means onboard of a equipped with a corresponding vehicle lamp vehicle with a voltage threshold realizing, discrete circuit structure.
• 8th a third embodiment of a Schmitt circuit at least as a part of comparison means for comparing a vehicle electrical system voltage of the vehicle power supply of the illuminating vehicle supplying a vehicle equipped with a corresponding vehicle lamp with a voltage threshold realizing circuit structure with operational amplifier.
• 9 a circuit diagram of an integrated electronic component, which realizes a Schmitt circuit at least as a part of comparison means for comparing a vehicle electrical system voltage of the illuminating means supplying the on-board network of a vehicle equipped with a corresponding vehicle lamp with a voltage threshold, wherein the in 9 a) illustrated circuit diagram shows an integrated electronic component, which implements a Schmitt circuit which forms an inverting Schmitt trigger, and in 9 b) 2 shows an integrated electronic component which implements a Schmitt circuit which forms a non-inverting Schmitt trigger.
• 10 a switching voltage input voltage diagram of a Schmitt circuit with frequent switching back and forth between two output voltages U _{a max} and U _{a min} at around a voltage threshold U _S back and forth fluctuating input voltage U _e avoiding hysteresis, where the output voltages U _a above the input voltage U _e is applied.

An in 3 in its process illustrated method for operating a in his diagram in 1 . 2 . 4 . 5 wholly or partially illustrated, provided for a vehicle light bulb 01 with several semiconductor light sources 02 , The circuit arrangement with lowered vehicle electrical system voltage in 1 , And its circuit arrangement at normal vehicle electrical system voltage in 2 is shown in whole or in part, looks in a first step I the formation of at least two semiconductor light source groups 03 each with a linear current source 04 and at least one connected to this semiconductor light source strand 05 from in each case at least two series-arranged semiconductor light sources 02 in front.

At least two semiconductor light sources arranged in series 02 are considered as a semiconductor light source strand 05 designated.

One as a circuit block or short block ( BL ; Block in 4 . 5 ) designated semiconductor light source group 03 on the other hand, denotes a linear current source 04 with a connected to this semiconductor light source strand 05 or a linear current source 04 with several parallel to each other connected to these semiconductor light source strands 05 , A semiconductor light source group 03 hereinafter comprises the linear current source 04 and at least one semiconductor light source string connected thereto 05 ,

In a linear current source 04 it is a current source, whose current corresponds to the current from the voltage applied at its connection points in a current-voltage diagram of a straight line with a negative gradient. It can be described in the equivalent circuit diagram as an ideal current source with an internal resistance in parallel.

In one on the first procedural step I following second process step II the method sees the detection of a vehicle electrical system voltage U one with at least one vehicle lamp with at least one corresponding illuminant 01 equipped vehicle before.

One of the electrical system voltage U proportional supply voltage U ₀ serves to operate the bulb 01 , This supply voltage U ₀ can be equal to the vehicle electrical system voltage U his.

In one, to the second process step II subsequent third step III the method sees the comparison of the detected vehicle electrical system voltage U with a voltage threshold U _S in front.

Is the result of the third step III conducted comparison that the detected vehicle electrical system voltage U is higher than the voltage threshold U _S , so there is a normal vehicle electrical system voltage.

In the case of the presence of normal vehicle electrical system voltage as a result of the third step III The comparison then looks at the third step of the procedure III following fourth process step IV a schematic in 2 shown interconnection of at least two each a linear current source 04 comprehensive semiconductor light source groups 03 in series with a semiconductor light source group strand 06 in front.

The interconnection of two or more of the one linear current source 04 comprehensive semiconductor light source groups 03 in series with a semiconductor light source group strand 06 Accordingly, according to the method takes place in the fourth step IV with a normal vehicle electrical system voltage U higher than the voltage threshold U _S ,

The method can be hereafter as in 3 through an arrow A indicated again from the second step II be repeated, for example, as long as at least one with a corresponding light source 01 comprehensive vehicle light equipped vehicle is in operation and / or by a corresponding light source 01 realized light function of a vehicle lamp is needed. This can be done for example by querying a position of an ignition key and / or the position of a corresponding light function activating switch.

Is the result of the third step III conducted comparison that the detected vehicle electrical system voltage U is lower than the voltage threshold U _S , so there is a lowered vehicle electrical system voltage.

In the case of the presence of lowered vehicle electrical system voltage as a result of the third step III On the other hand, the procedure looks at the third procedural step III following fifth process step V a changeover between the normal vehicle electrical system voltage higher than the voltage threshold U _S as in 2 schematically shown in series with a semiconductor light source group strand 06 interconnected semiconductor light source groups 03 to one in 1 schematically shown arrangement in which the respective one linear current source 04 comprehensive semiconductor light source groups 03 of the semiconductor light source group strand 06 are connected in parallel.

The interconnection of the at least two each a linear current source 04 comprehensive and with normal vehicle electrical system voltage higher than the voltage threshold U _S as in 2 schematically shown in series with a semiconductor light source group strand 06 interconnected semiconductor light source groups 03 parallel to each other, as in 1 is shown schematically, accordingly according to the method in the fifth step V at a lowered vehicle electrical system voltage U lower than the voltage threshold U _S ,

The method can be hereafter as in 3 through an arrow B indicated again from the second step II be repeated, for example, as long as at least one with a corresponding light source 01 comprehensive vehicle light equipped vehicle is in operation and / or by a corresponding light source 01 realized light function of a vehicle lamp is needed. This can be done for example by querying a position of an ignition key and / or the position of a corresponding light function activating switch.

The method for operating a lamp provided for a vehicle lamp 01 with several semiconductor light sources 02 thus provides at least two semiconductor light source groups 03 each with at least one semiconductor light source strand 05 from in each case at least two series-arranged semiconductor light sources 02 to build.

The method further contemplates each semiconductor light source group 03 with a linear current source also referred to as a semiconductor light source driver 04 to which the at least one semiconductor light source strand is to be provided 05 the corresponding semiconductor light source group 03 connected.

In addition, the method provides a detection of the vehicle electrical system voltage U one with a corresponding light source 01 comprehensive vehicle lamp equipped vehicle and the comparison of the detected vehicle electrical system voltage U with a voltage threshold U _S in front.

The procedure provides for normal vehicle electrical system voltage higher than the voltage threshold U _S two or more of each a linear current source 04 comprehensive semiconductor light source groups 03 in series with a semiconductor light source group strand 06 to interconnect.

The method also sees a switching between the normal vehicle electrical system voltage higher than the voltage threshold U _S in series with a semiconductor light source group strand 06 interconnected semiconductor light source groups 03 to an arrangement before, when the vehicle electrical system voltage is lower than the voltage threshold U _S each a linear current source 04 comprehensive semiconductor light source groups 03 of the semiconductor light source group strand 06 are connected in parallel.

By switching between two or more at normal vehicle electrical system voltage to a semiconductor light source group strand 06 series-arranged semiconductor light source groups 03 to a parallel arrangement of the semiconductor light source groups 03 When lowered vehicle electrical system voltage can all semiconductor light sources 02 of the bulb 01 be operated reliably under all operating conditions of the vehicle, especially when the automatic start-stop system is switched on.

By the interconnection of two or more semiconductor light source groups 03 in series with a semiconductor light source group strand 06 with normal vehicle electrical system voltage higher than the voltage threshold U _S results in the normal prevailing driving a reduction in power loss compared to maintaining the lowered vehicle electrical system voltage lower than the voltage threshold U _S ruling arrangement above the voltage threshold U _S ,

Through in each semiconductor light source group 03 provided linear current source 04 may be a failure of one or more semiconductor light sources 02 per semiconductor light source group 03 be recognized.

The method may provide that the semiconductor light source strands 05 the semiconductor light source groups 03 in each case from one of the number of semiconductor light sources which can be operated in series at a minimal prevailing vehicle supply voltage 02 corresponding number of semiconductor light sources arranged in series 02 be formed.

In order to reduce the electrical control power and thus the electrical power loss, it makes sense so many semiconductor light sources 02 as possible to connect in series, the number of maximum electrically arranged in a row semiconductor light sources 02 , such as LEDs or OLEDs, is predetermined by the minimum prevailing vehicle electrical system voltage.

By arranging in each case a number of semiconductor light sources which can be operated in series with a minimal prevailing vehicle electrical system voltage 02 per semiconductor light source group 03 in series, the operation of the semiconductor light sources 02 within the semiconductor light source groups 03 be ensured even when lowered vehicle electrical system voltage.

By the arrangement of a linear current source 04 per semiconductor light source group 03 and by restricting an arrangement within each semiconductor light source group 03 in each case one of the number of semiconductor light sources which can be operated in series at a minimal prevailing vehicle supply voltage 02 corresponding number of semiconductor light sources 02 in series with a semiconductor light source strand 05 becomes the requirement for operability of all semiconductor light sources 02 a semiconductor light source group 03 met at minimal prevailing vehicle electrical system voltage.

The method may alternatively or additionally provide that each semiconductor light source group 03 one or more in this case within the semiconductor light source group 03 parallel to the linear current source 04 connected semiconductor light source strands 05 includes, as in 1 and 2 is shown schematically.

A method described above can by a suitable for carrying out a method described above, in its circuit diagram in 1 . 2 . 4 . 5 , in whole or in part illustrated bulbs 01 for a vehicle lamp, the circuit arrangement with lowered vehicle electrical system voltage in 1 , And its circuit arrangement at normal vehicle electrical system voltage in 2 shown in whole or in part, be realized.

A vehicle lamp for which a corresponding light source 01 can be provided includes, for example, a substantially enclosed by a lamp housing and a lens interior and at least one housed therein, at least one light source comprehensive light source for at least one light function of the vehicle lamp.

Each vehicle lamp fulfills one or more tasks or functions depending on the design. To fulfill each task or function, a light function of the vehicle lamp is provided. Lighting functions, for example, in one embodiment as a headlamp a function illuminating the road, or in a configuration as a signal light a signal function, such as a Wiederholblinklichtfunktion the direction indicator or a brake light function to display a braking action, or eg a limiting light function, such as a taillight function, to ensure a Visibility of the vehicle during the day and / or night, such as in a design as tail light or daytime running light. Examples of vehicle lights are on Fahrzeugbug, on the vehicle flanks and / or on the side mirrors and the rear of the vehicle arranged flashing lights, exit lights, for example Ambient lighting, side lights, brake lights, fog lights, reversing lights, and typically high set third brake lights, so-called Central, high-mount Braking Lights, daytime running lights, headlights and fog lamps used as turn or cornering lights, and combinations thereof.

Each light function must fulfill an example prescribed by law light distribution. The light distribution sets at least to be observed, colloquially known as brightness luminous flux in at least to be observed solid angle ranges.

For the individual lighting functions, there are sometimes different brightnesses or visibility ranges and, in some cases, different light colors.

At least one light source of the luminous means of a vehicle lamp can be assigned one or more optical elements contributing to the shaping of a light distribution for directing the light.

The lens is formed by a transparent cover which is usually made of a plastic material today, which closes off the interior of the lamp and protects the components housed therein, such as one or more lamps, reflectors and alternatively or additionally provided optical elements against the effects of weathering.

The luminaire housing or the interior of the luminaire can be subdivided into a plurality of chambers, each with its own light sources and / or illuminants and / or optical elements and, if appropriate, light disks, of which several chambers can be identical and / or each chamber can fulfill a different lighting function.

The optical elements mentioned can be at least one reflector and / or at least one lens and / or one or more optical disks or the like arranged in the beam path between at least one light source of the luminous means and the light disk.

For example, at least one reflector arranged behind at least one light source of at least one luminous means can be accommodated in the luminaire interior. The reflector may be formed at least in part by a separate component and / or by at least one part of the luminaire housing itself, for example by means of an at least partially reflective coating.

The lens itself may alternatively or additionally be formed as an optical element, for example by being preferably provided on the inside with an optical structure contributing to the production of one or more light distributions mentioned above. This may possibly be dispensed with an optical disk.

Examples of vehicle lights are the Fahrzeugbug, on the vehicle flanks and / or on the side mirrors and arranged at the rear of vehicle rear lights, exit lights, such as ambient lighting, marker lights, brake lights, fog lamps, reversing lights, and typically high set third brake lights, so-called Central, High-Mounted Braking lights, daytime running lights, headlamps and fog lights used as turning or cornering lights, as well as combinations thereof.

Such a combination is realized, for example, regularly in the known taillights. These include, for example, repeating flashing lights, marker lights, brake lights, fog lights and reversing lights are used to name just one of many realized in tail lights combinations. Neither does this enumeration claim to be complete, nor does this mean that in a tail light all the aforementioned lights must be combined. Thus, for example, only two or three of the mentioned or else other lights in a common luminaire housing a tail light be combined.

• - mindestens zwei Halbleiterlichtquellen-Gruppen 03 mit jeweils einer Linearstromquelle 04 und mindestens einem an die Linearstromquelle 04 angeschlossenen Halbleiterlichtquellen-Strang 05 mit wenigstens zwei in Serie angeordneten Halbleiterlichtquellen 02,
• - in 6, 7, 8, 9 beispielhaft ganz oder teilweise dargestellte Vergleichsmittel 07 zum Vergleich einer Bordnetzspannung U eines die Stromversorgung des Leuchtmittels 01 besorgenden Bordnetzes eines mit einer entsprechenden Fahrzeugleuchte ausgestatteten Fahrzeugs mit einem Spannungs-Schwellenwert U_S , und
• - mit den Vergleichsmitteln 07 verbundene Schaltungsmittel 08 zur Umschaltung zwischen einer in 2 in ihrem Schaltungsaufbau prinzipiell dargestellten Anordnung, bei der bei normaler Bordnetzspannung höher als der Spannungs-Schwellenwert U_S zwei oder mehr jeweils eine Linearstromquelle 04 umfassende Halbleiterlichtquellen-Gruppen 03 in Serie zu einem Halbleiterlichtquellen-Gruppen-Strang 06 angeordnet sind, zu einer in 1 in ihrem Schaltungsaufbau prinzipiell dargestellten Anordnung, bei der bei abgesenkter Bordnetzspannung niedriger als der Spannungs-Schwellenwert U_S die jeweils eine Linearstromquelle 04 umfassenden Halbleiterlichtquellen-Gruppen 03 des Halbleiterlichtquellen-Gruppen-Strangs 06 parallel verschaltet sind.

A in its circuit arrangement with lowered vehicle electrical system voltage in 1 , and in its circuit arrangement with normal vehicle electrical system voltage in 2 completely or partially illustrated bulbs 01 with several semiconductor light sources 02 for a vehicle lamp includes:

• - At least two semiconductor light source groups 03 each with a linear current source 04 and at least one of the linear current source 04 connected semiconductor light source strand 05 with at least two semiconductor light sources arranged in series 02 .
• - in 6 . 7 . 8th . 9 exemplified in whole or in part comparative means 07 to compare a vehicle electrical system voltage U one is the power supply of the bulb 01 vehicle electrical system of a vehicle equipped with a corresponding vehicle lamp with a voltage threshold U _S , and
• - with the comparison means 07 connected circuit means 08 to switch between an in 2 In principle, in its circuit structure illustrated arrangement, at the normal vehicle electrical system voltage higher than the voltage threshold U _S two or more each a linear current source 04 comprehensive semiconductor light source groups 03 in series with a semiconductor light source group strand 06 are arranged to one in 1 in principle arrangement shown in their circuit construction, in which at lowered vehicle electrical system voltage lower than the voltage threshold U _S each a linear current source 04 comprehensive semiconductor light source groups 03 of the semiconductor light source group strand 06 are connected in parallel.

The lamp provided for a vehicle lamp 01 with several semiconductor light sources 02 therefore comprises at least two semiconductor light source groups 03 each consisting of a linear current source 04 and at least one of the linear current source 04 connected semiconductor light source strand 05 of at least two semiconductor light sources arranged in series 02 ,

In addition, the illuminant includes 01 comparison means 07 for comparison of a power supply of the bulb 01 providing the vehicle electrical system voltage with a voltage threshold.

In addition, the bulb includes 01 with the comparison means 07 connected circuit means 08 for switching between an arrangement in which at normal vehicle electrical system voltage higher than the voltage threshold U _S two or more each a linear current source 04 comprehensive semiconductor light source groups 03 in series with a semiconductor light source group strand 06 are arranged to an arrangement in which with lowered vehicle electrical system voltage lower than the voltage threshold U _S at normal vehicle electrical system voltage higher than the voltage threshold U _S to the semiconductor light source group strand 06 interconnected and each a linear current source 04 comprehensive semiconductor light source groups 03 are connected in parallel, or at least two of the normal vehicle electrical system voltage higher than the voltage threshold U _S to the semiconductor light source group strand 06 interconnected and each a linear current source 04 comprehensive semiconductor light source groups 03 are connected in parallel.

In the 6 . 7 . 8th . 9 exemplified in whole or in part comparative means 07 to compare a vehicle electrical system voltage U one is the power supply of the bulb 01 vehicle electrical system of a vehicle equipped with a corresponding vehicle lamp with a voltage threshold U _S can the actual vehicle electrical system voltage U or one of the vehicle electrical system voltage U proportional voltage, for example a supply voltage U ₀ and / or one of a circuit construction for realizing the comparison means 07 to compare the vehicle electrical system voltage U with a voltage threshold U _S applied input voltage U _e with a corresponding voltage threshold U _S to compare.

Is there the to be compared, the vehicle electrical system voltage U proportional voltage, for example a supply voltage U ₀ and / or one at a comparison means 07 implementing circuit voltage applied input voltage U _e, below the corresponding voltage threshold U _S so give the comparison means 07 an output voltage U _a from which the circuit means 08 for switching between an arrangement in which at normal vehicle electrical system voltage higher than the voltage threshold U _S two or more each a linear current source 04 comprehensive semiconductor light source groups 03 in series with a semiconductor light source group strand 06 are arranged to an arrangement in which with lowered vehicle electrical system voltage lower than the voltage threshold U _S at normal vehicle electrical system voltage higher than the voltage threshold U _S to the semiconductor light source group strand 06 interconnected and each a linear current source 04 comprehensive semiconductor light source groups 03 are connected in parallel, or at least two of the normal vehicle electrical system voltage higher than the voltage threshold U _S to the semiconductor light source group strand 06 interconnected and each a linear current source 04 comprehensive semiconductor light source groups 03 in parallel, cause.

The circuit means 08 can do this as in 5 shown several switches 81 . 82 . 83 of which in that circuit state forming the arrangement, at the normal vehicle electrical system voltage higher than the voltage threshold U _S two or more each a linear current source 04 comprehensive semiconductor light source groups 03 in series with a semiconductor light source group strand 06 are arranged, the switch 82 is closed and the switches 81 and 83 are open. In the circuit state which forms the arrangement, when the vehicle electrical system voltage is lower than the voltage threshold value U _S those at normal vehicle electrical system voltage higher than the voltage threshold U _S to the semiconductor light source group strand 06 interconnected and each a linear current source 04 comprehensive semiconductor light source groups 03 are connected in parallel, or at least two of the normal vehicle electrical system voltage higher than the voltage threshold U _S to the semiconductor light source group strand 06 interconnected and each a linear current source 04 comprehensive semiconductor light source groups 03 are connected in parallel, the switch 82 is open and the switches 81 and 83 are closed.

In the comparison means 07 for comparison of a power supply of the bulb 01 caring electrical system voltage U with a voltage threshold U _S For example, it may be an in 6 . 7 . 8th . 9 shown in part or in part, also known as so-called Schmitt trigger Schmitt circuit 10 act. Alternatively or additionally, the comparison means 07 for comparison of a power supply of the bulb 01 caring electrical system voltage U with a voltage threshold U _S a Schmitt known as a so-called Schmitt trigger Schmitt circuit include.

Advantageously, the comparison means 07 for comparison of a power supply of the bulb 01 caring electrical system voltage U with a voltage threshold U _S an adjustable hysteresis on. Include the comparison means 07 for comparison of a power supply of the bulb 01 caring electrical system voltage U with a voltage threshold U _S a Schmitt circuit known as the so-called Schmitt trigger or the comparison means 07 for comparison of a power supply of the bulb 01 caring electrical system voltage U with a voltage threshold U _S formed by a known as so-called Schmitt trigger Schmitt circuit, it advantageously has a hysteresis, particularly preferably an adjustable hysteresis.

The hysteresis avoids unwanted switching back and forth at around the voltage threshold fluctuating on-board voltage ( 10 ). In this case, the on and off voltage thresholds do not coincide. Instead, the on and off voltage thresholds are around a certain voltage _One - U _{e out} offset against each other. This offset of the on and off voltage thresholds is also referred to as the switching hysteresis. Reaches the input voltage U _e , which is the voltage to be compared, here the vehicle electrical system voltage, the turn-on voltage threshold _One , so at the output of the circuit is the switching voltage U _{a max} on. Decreases the input voltage U _e below the switch-off voltage threshold U _{e out} , so at the output of the circuit is the switching voltage U _{a min} on. The switching voltages U _{a max} . U _{a min} can be used to make a in 5 to operate shown switching.

Examples of circuit diagrams of wholly or partly for the realization of comparison means for comparing a power supply voltage of the illuminating vehicle board voltage with a voltage threshold suitable circuits are in 6 . 7 . 8th . 9 shown.

U ₁ here denotes the mass which is also typically designated GND for ground, U ₀ this also known as supply voltage Vcc permanent plus.

9 shows in 9 a) the diagram of an integrated electronic component, which is a Schmitt circuit 10 realized that forms an inverting Schmitt trigger. 9 shows in 9 b) the diagram of an integrated electronic component, which is a Schmitt circuit 10 which forms a non-inverting Schmitt trigger.

The number of semiconductor light sources 02 per semiconductor light source strand 05 in each case one of the number of semiconductor light sources which can be operated in series at a minimal prevailing vehicle supply voltage can be used 02 correspond.

Per semiconductor light source group 03 can use multiple semiconductor light source strands 05 parallel to each other to the linear current source 04 the semiconductor light source group 03 be connected and powered by this or be supplied, as in a by the in 1 and 2 shown schematically schematics shown bulbs 01 the case is.

It is important to emphasize that it is the semiconductor light sources 02 of the bulb 01 around similar semiconductor light sources 02 can act, or to various semiconductor light sources 02 ,

For example, at least one of the semiconductor light sources may be used 02 to act an LED.

In principle, it can also be with all semiconductor light sources 02 to act on LEDs.

For example, at least one of the semiconductor light sources may be used 02 to act an OLED.

In principle, it can also be with all semiconductor light sources 02 to act OLEDs.

In summary, the invention provides for increasing the efficiency associated with the possibility of detecting the failure of one or more semiconductor light sources 02 , such as LEDs in front, two or more semiconductor light source groups, referred to as circuit blocks for short 03 , each consisting of a linear current source, also referred to as an LED driver 04 and a semiconductor light source strand connected and powered thereto 05 of two or more semiconductor light sources connected in series 02 , in particular LEDs, with lowered vehicle electrical system voltage in parallel and at short as rated voltage designated normal vehicle electrical system voltage in series.

Therefore, a linear current source, also referred to as an LED driver, will be used for at least two, advantageously for a number of semiconductor light sources connected in series 02 how LEDs use what number of semiconductor light sources 02 how LEDs can be supplied with lowered, for example, minimum vehicle electrical system voltage in series with the LED driver.

When briefly also referred to as rated voltage normal vehicle electrical system voltage, for example when the generator is running, results from an arrangement of two from a linear current source 04 supplied or connected to these and arranged in series semiconductor light sources 02 without further measures a poor efficiency.

To counter this, the invention provides, at rated voltage, at least two semiconductor light source groups 03 in series, which increases the efficiency.

When the vehicle electrical system voltage is lowered, however, the invention provides for the at least two semiconductor light source groups 03 to switch in parallel, whereby with lowered vehicle electrical system voltage all semiconductor light sources 02 of the bulb 01 operate.

By doing that, each group of semiconductor light sources 03 a linear current source 04 includes, it is possible that the failure of individual semiconductor light sources 02 , such as LEDs of the bulb 01 can be detected.

This is in 5 through a failure detection block 09 shown with each semiconductor light source group 03 of the bulb 01 , in particular in each case with the linear current source 04 each semiconductor light source group 03 of the bulb 01 connected is.

In 4 a) a is a linear current source 04 realizing driver chip, for example TPS92610-q1, with LEDs as semiconductor light sources 02 ,

The entire presentation in 4 a) is in 4 b) as a semiconductor light source group 03 forming part BL summarized.

Several, for example as in 5 shown two, each as a semiconductor light source group 03 forming part BL assembled components are then as in 5 represented, for example, connected in series or in parallel via a circuit of MOSFATs. If needed, can by a failure detection block 09 also a failure detection be realized.

• - Bildung mindestens zweier Halbleiterlichtquellen-Gruppen 03 mit jeweils einer Linearstromquelle 04 sowie mindestens einem an diese angeschlossenen Halbleiterlichtquellen-Strang 05 aus jeweils zumindest zwei in Serie angeordneten Halbleiterlichtquellen 02,
• - Erfassung einer Bordnetzspannung U eines mit der Fahrzeugleuchte ausgestatteten Fahrzeugs,
• - Vergleich der erfassten Bordnetzspannung U mit einem Spannungs-Schwellenwert U_S ,
• - Verschaltung mindestens zweier Halbleiterlichtquellen-Gruppen 03 in Serie zu einem Halbleiterlichtquellen-Gruppen-Strang 06 bei einer normalen Bordnetzspannung höher als der Spannungs-Schwellenwert U_S , und
• - Umschaltung zwischen den bei normaler Bordnetzspannung höher als der Spannungs-Schwellenwert U_S in Serie zu einem Halbleiterlichtquellen-Gruppen-Strang 06 verschalteten Halbleiterlichtquellen-Gruppen 03 zu einer Anordnung, bei der die Halbleiterlichtquellen-Gruppen 03 parallel verschaltet sind, bei einer abgesenkten Bordnetzspannung niedriger als der Spannungs-Schwellenwert U_S .

It is important to emphasize that the light source 01 allows a method for operating a light provided for a vehicle lamp 01 with several semiconductor light sources 02 to carry out, comprising the method steps:

• - Formation of at least two semiconductor light source groups 03 each with a linear current source 04 and at least one connected to this semiconductor light source strand 05 from in each case at least two series-arranged semiconductor light sources 02 .
• - Detection of a vehicle electrical system voltage U a vehicle equipped with the vehicle lamp,
• - Comparison of the detected vehicle electrical system voltage U with a voltage threshold U _S .
• - Connection of at least two semiconductor light source groups 03 in series with a semiconductor light source group strand 06 at a normal vehicle electrical system voltage higher than the voltage threshold U _S , and
• - Switchover between the normal vehicle electrical system voltage higher than the voltage threshold U _S in series with a semiconductor light source group strand 06 interconnected semiconductor light source groups 03 to an arrangement in which the semiconductor light source groups 03 are connected in parallel, with a lowered vehicle electrical system voltage lower than the voltage threshold U _S ,

The semiconductor light source strands 05 the semiconductor light source groups 03 can in each case from one of the minimum ruling vehicle electrical system voltage in series operable number of semiconductor light sources 02 corresponding number of semiconductor light sources arranged in series 02 be formed.

Each semiconductor light source group 03 may be one or more in this case within the semiconductor light source group 03 parallel to the linear current source 04 connected semiconductor light source strands 05 include.

The invention thus eliminates the disadvantages of the prior art by a variable interconnection of the circuit blocks from parallel to serial and vice versa.

Advantages result from maintaining the possibility of detection of the failure of individual or multiple semiconductor light sources 02 , In particular LEDs, by means of the LED driver, along with a high efficiency and low power dissipation and with a prevention of flickering by a semiconductor light sources 02 , as about LEDs realized light function in vehicles with automatic start-stop.

Further advantages result from a simple scalability due to the modular construction of circuit blocks.

Additional advantages result from the availability of standard components for the power supply of semiconductor light sources 02 , like LEDs.

It can be seen that the invention provides for the solution of the task, also referred to as blocks or circuit blocks groups of semiconductor light sources 02 , such as LEDs and / or OLEDs, and these, each with a linear current source 04 For example, to interconnect an LED driver so that the semiconductor light sources 02 the blocks work at minimum voltage. Thus, these blocks can be operated in parallel with minimum vehicle electrical system voltage. At rated voltage, the blocks are switched in series. This includes all the functions of the linear current sources 04 , such as failure detection of individual semiconductor light sources of the blocks.

In vehicle applications, usually only LED strings with two LEDs are feasible because the minimum prevailing vehicle electrical system voltage is about 7V. However, the normal vehicle electrical system voltage prevailing during driving is 13.5V and thus makes it possible to connect four LEDs in series.

The invention allows the switching of, for example, two LED blocks with LED strings with two LEDs in series. By assigning each a linear current source 04 For each block, the full range of functions of the LED driver is available, such as a failure detection.

Further advantages over the prior art are that standard components can be used. These can be optimally thermally operated, for example in order to reduce the required board area or to save cooling plates.

Additional advantages include a simple way of scaling and opening the possibility to use the functions that are included in an LED driver, in particular the failure detection.

The light source 01 and / or the method may alternatively or additionally comprise single or a combination of several in the context of the prior art and / or in one or more of the documents mentioned in the prior art and / or features mentioned in the preceding description.

The light source 01 may comprise single or a combination of the features described above in connection with the method, as well as the method individual or a combination of several previously and / or subsequently in connection with the lighting means 01 have described features and / or can realize.

The invention is not limited by the description with reference to the embodiments. Rather, the invention encompasses any novel feature as well as any combination of features, including in particular any combination of features in the claims, even if that feature or combination itself is not explicitly stated in the claims or embodiments.

The invention is particularly industrially applicable in the field of manufacturing vehicle lights, in particular motor vehicle lights.

The invention has been described with reference to preferred embodiments. However, it will be apparent to those skilled in the art that modifications or changes may be made to the invention without departing from the scope of the following claims.

LIST OF REFERENCE NUMBERS

01

Lamp

02

Semiconductor light source

03

Semiconductor light sources group

04

Linear power supply

05

Semiconductor light sources strand

06

Semiconductor light source groups strand

07

comparison means

08

circuit means

09

Failure detection block

10

Schmitt circuit

81

counter

82

counter

83

counter

U

Board supply voltage

U ₀

supply voltage

U _S

Voltage threshold value

U _e

input voltage

U _a

output voltage

U ₁

Dimensions

I

step

II

step

III

step

IV

step

V

step

A

arrow

B

arrow

BL

block

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2007108843 A1 [0021]
• US 2013207548 A1 [0023]
• EP 3193563 A1
• DE 102006024607 A1 [0028]

Claims (5)

Light source (01) with a plurality of semiconductor light sources (02) for a vehicle lamp, comprising: - at least two semiconductor light source groups (03) each having a linear current source (04) and at least one connected to this semiconductor light source strand (05) with at least two arranged in series Semiconductor light sources (02), - comparing means for comparing a vehicle electrical system voltage (U) with a voltage threshold (U _S ), and - connected to the comparison means switching means for switching between an arrangement in which normal at board voltage higher than the voltage threshold (U _S ) at least two semiconductor light source groups (03) are arranged in series with a semiconductor light source group strand (06), to an arrangement in which with lowered vehicle electrical system voltage lower than the voltage threshold (U _S ), the semiconductor light source groups (03 ) of the semiconductor light source group string (06) are connected in parallel. Bulbs after Claim 1 , Wherein the number of semiconductor light sources (02) per semiconductor light source strand (05) corresponds in each case to one of the number of semiconductor light sources (02) which can be operated in series with a minimal prevailing vehicle supply voltage. Bulbs after Claim 1 or 2 , wherein each semiconductor light source group (03) a plurality of semiconductor light source strands (05) parallel to each other to the linear current source (04) of the semiconductor light source group (03) connected and powered by these with electricity and / or supplied. Bulbs after Claim 1 . 2 or 3 wherein at least one of the semiconductor light sources (02) is an LED. Bulbs according to one of Claims 1 to 4 wherein at least one of the semiconductor light sources (02) is an OLED.

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