WO2020035131A1

WO2020035131A1 - Arrangement for operating at least one light source of a vehicle

Info

Publication number: WO2020035131A1
Application number: PCT/EP2018/072005
Authority: WO
Inventors: Helmut Sebastian
Original assignee: HELLA GmbH & Co. KGaA
Priority date: 2018-08-14
Filing date: 2018-08-14
Publication date: 2020-02-20

Abstract

The invention relates to an arrangement (10) for operating at least one light source (2) of a vehicle, particularly with at least one light-emitting diode, comprising: - a supply line (20) for providing an electrical input signal (5) from a control device (1 ) of the vehicle, wherein the supply line (20) is suitable for transmitting the input signal (5) as a supply signal to the light source (2) in an active mode of the light source (2), and otherwise for providing the input signal (5) as a signal which is intended for a functional test of the light source (2) in a disabled mode of the light source (2), - a simulation component (30) for providing a load in the disabled mode, wherein the load is adapted to be evaluated by the functional test instead of the light source (2), - a detection component (40) for detecting at least one of the modes by using the input signal (5) and for operating the simulation component (30) depending on the detection.

Description

Arrangement for operating at least one light source of a vehicle

Description

The invention is related to an arrangement for operating at least one light source of a vehicle. Furthermore, the invention is related to a method for operating at least one light source of a vehicle.

It is known from the prior art that conventional electronic control units of a vehicle output a test signal comprising short voltage pulses through a supply line to a lighting means (light source), which is used for a functional test of the lighting means. The functional test can be used for detecting the presence of the lighting means, like an incandescent lamp. When the lighting means is in an switched-off (disabled) state, the lighting means is very low-resistance and is therefore detected as low-resistance closure of the supply line. However, when the wire filament of the lamp is destroyed, the lamp becomes high-resistance which can be detected as an interruption and as a fault by the functional test. However, when another kind of lighting means is used, for example a semiconductor based lamp, such a test fails.

The voltage pulses can particularly be output repeatedly each for only a short duration (e. g. smaller than 10 ms). Incandescent lamps are not affected by such short signals. However, semiconductor based lamps may shortly emit light visible as a flickering of the lamp synchronous to the pulses.

The object of the present invention is to at least partially avoid the previously described disadvantages. Particularly, it is the object of the present invention to prevent an unwanted operation, e. g. flickering, of the light source effected by the test function.

Aforesaid problem is solved by an arrangement with the features of claim 1 and a method with the features of claim 9. Features and details of the present invention result from the subclaims, the description and the respective drawings. Features and details discussed with respect to the inventive arrangement are also related to features and details discussed with respect to the inventive method.

Particularly, the invention relates to an electrical and/or electronical arrangement, preferably circuit arrangement or circuitry, for operating at least one light source (lighting means) of a vehicle, particularly wherein the lightsource has at least one light- emitting diode.

Furthermore, the arrangement comprises a supply line for providing an electrical input signal from a control device of the vehicle. The arrangement can advantageously be suitable for being connected to the control device and to the light source through this supply line.

The control device is e. g. an electronic control unit of the vehicle for controlling at least one automotive lighting device, like the light source, of a lighting system of the vehicle. The light source is especially part of this lighting system and particularly configured as a head lamp or rear lamp, like a tail lamp or brake lights. The light source can also be configured as a rear lamp of a trailer which is towed by a powered vehicle. Then particularly the powered vehicle can comprise the control device connected to the light source via the arrangement according to the invention.

The vehicle is preferably embodied as a motor vehicle, particularly a truck (e. g. with a trailer) or passenger car. It can also be configured as an electrical vehicle with or without additional combustion engine.

The light source is preferably embodied according to a (actual) lamp technology that differs from a (intended) lamp technology the control device is designed for. For example, the control device can be designed or intended for a lamp technology like an incandescent lamp or electric light bulb whereas the light source is configured as a semiconductor-based light source. Therefore, the light source can comprise at least one light-emitting diode and/or corresponding electronics. This difference can also be described in a way that the actual lamp technology already operates or emits light with a lower supply signal (like a smaller supply voltage) than the intended lamp

technology (in the following referred to as a threshold for operation) and/or that the intended lamp technology has a low resistance in the disabled mode (disabled state of the light source) wherein the actual lamp technology has in comparison to the intended lamp technology a higher resistance in the disabled mode. This particularly affects a functional test of the control device, wherein a test signal (interrogation signal) is output (onto the supply line) to the light source for testing the functionality of the light source. Conventionally, the test signal detects the low resistance of a light source according to the intended lamp technology. However, when connecting the actual lamp technology directly to the control device, a fault is detected due to the higher resistance. Also, flickering of the light source can occur due to the lower threshold for operation. The arrangement according to the invention addresses this problem.

The arrangement according to the invention can also comprise a supply line that is suitable for transmitting the input signal as a supply signal to the light source

(especially so that an energy supply for the light source is provided and/or that the ligh source emits light) in an active mode of the light source, and otherwise for providing the input signal as a signal which is intended for a functional test of the light source in a disabled mode of the light source (i. e. in a disabled state where the light source does not emit light).

It can be possible that a simulation component of the arrangement according to the invention is used for providing (activating), particularly by switching in, a (electrical) load in the disabled mode, wherein the load can be adapted to be evaluated by the functional test instead of the light source. This effect can particularly be achieved when the load has a low resistance, preferably a resistance similar (or equal) to the resistance of the intended lamp technology (as described above) in the disabled mode and/or much lower than the resistance of the light source in the disabled mode.

Therefore, the activation of the load can be regarded as a simulation of the“intended” lamp technology expected by the control device, for instance of a conventional light technology like an incandescent lamp that differs from the actually used light source. The simulation component enables an evaluation of the load instead of the light source so that the light source is not significantly affected by the input signal.

However, in the active mode of the light source (when light should be emitted) the input (or supply) signal has a much higher electrical power than in the disabled mode for the functional test. Therefore, in the event of a continuing simulation by the simulation component (that means a continuing activation of the load) the simulation component can be damaged by the higher electrical power.

Particularly for the above-mentioned reason, a detection component can be used for detecting at least one of the modes by using the input signal and for operating the simulation component depending on the detection. In other words, the operation of the simulation component (that means in particular: activating the load and deactivating the load) can be controlled by the detection component. For that purpose, the detection component can provide a self-shutdown mechanism that detects the active mode and performs a shutdown of at least the simulation component or the entire arrangement when the active mode is positively detected. After deactivation of the active mode, the arrangement and/or the simulation component can directly be ready for providing the load again.

Preferably, it is provided that that the simulation component is configured to prevent a sufficient energy supply of the light source by the input signal in the disabled mode, particularly by providing the load with a low resistance so that a flickering of the light source by the input signal is prevented.

It is also conceivable that the detection component is configured to distinguish between a short pulse signal as the input signal specific for the functional test and the supply signal with a voltage higher than the short pulse signal. This allows for a reliable detection of the functional test in the disabled mode and/or of the active mode. It can be provided that the detection component is adapted to detect only one of the modes, since when one of the modes is not detected it can be concluded that the other of the modes is present.

According to the invention, it can also be possible that the detection component is configured to switch between a low-resistance of the arrangement in the disabled mode when the functional test is carried out by the control device and a high- resistance of the arrangement in the active mode. This can be done by activating the simulation component by the detection component.

Particularly, the simulation component is intended for a simulation of a lamp, preferably a lamp that differs from the light source regarding the technology and/or functional principle, particularly preferably an incandescent lamp. The simulation can e. g. be enabled by providing the load such that the load is specific for such a lamp in a disabled state, e. g. with the low resistance. The lamp is particularly a kind of lamp that is not used for the light source and/or for the vehicle. However, the control device can still be specific for this lamp and/or adapted to perform the functional test only for this kind of lamp and not for the light source.

The light source comprises e. g. at least one light emitting unit, particularly a light emitting diode or laser diode or the like. The arrangement according to the invention can therefore be configured to adapt the control device to the light source and/or to prevent a distortion or interference of the light source by the functional test.

Particularly, the simulation component is configured to intercept, preferably reduce, the input signal when the functional test is carried out in the disabled mode. The input signal can be configured as test signal, e. g. as an interrogation pulse in this case. The arrangement according to the invention and/or the simulation component can be connected in parallel or in series through the supply line with the light source and/or the control device, particularly to intercept this signal. Advantageously this can be done by providing a low-resistance load by the simulation component, which influences the input signal. Therefore, the simulation component can be electrically connected to the supply line. This can have the effect that the resulting supply voltage of the input signal is low enough to simulate the presence of a incandescent lamp and is as well low enough (e. g. below 2 V) to prevent the operation (flickering) of the light source connected to the supply line.

The active mode can be a mode in which the control device outputs a supply signal onto the supply line, which is used for operating the light source. In this active mode the light source can be supplied by a sufficient amount of energy using the supply signal so that the light source emits visible light.

The disabled mode can be a mode in which the light source is turned off so that the light source does not emit any light. However, in the disabled mode a functional test can be performed by the control device. For this test, the control device can output a test signal as the input signal onto the supply line. Preferably, the test signal has a smaller voltage than the supply signal. The supply line is advantageously electrically connected to the light source in both modes. Nevertheless, the test signal voltage can be too small to operate the light source. Furthermore, the test signal is preferably only a short pulse and therefore configured not to cause a regular operation of the light source.

However, if the test signal is fully transmitted to the light source this can cause a short activation in the form of flickering or the like. For that reason, the simulation

component can prevent this effect by providing (activating) the load in the disabled mode. This load can be adapted to be evaluated by the functional test, i. e. by the test signal, instead of the light source. In other words, by activating the load the functional test is not able to evaluate the light source directly. Instead, the functional test evaluates only the load. This can be explained by the functional principle of the functional test performed by the control device. For this test, the control device outputs the input signal as a test signal, particularly as a pulse signal, with only a small voltage. The test signal can have a voltage below 5 V (Volt), whereas the supply signal can have a voltage higher than 5 V. The test signal can e. g. be provided by outputting a supply voltage (through a series resistor) with high-resistance (of the control device) onto the supply line. By contrast, in the active mode the high- resistance is not used, and the supply voltage can be provided directly, e. g. through a relay or the like, onto the supply line (this is the supply signal). However, in the disabled mode when the functional test is performed the provided load can cause a low-resistance of the arrangement. When the detection component does not prevent the activation of the load the load can characterize the resistance of the whole arrangement significantly and effect a low-resistance of the arrangement. Since the arrangement can be connected to the control device and/or to the light source (e.g. in parallel), a low-resistance of the arrangement then acts like a short circuit (low- resistance) in the disabled mode when the functional test is carried out.

In the active mode the absence of the series resistance and/or high-resistance of the control device has the effect that the supply voltage is directly used for operating the light source. Furthermore, in the active mode an automatic shutoff can be performed by the arrangement using the detection component.

Within the scope of the invention the expression“resistance” can also refer to an impedance. Accordingly, the expression“low-resistance” can also refer to“low- impedance” and/or“low-ohmic”, and the expression“high-resistance” can also refer to “high-impedance” and/or“high-ohmic”.

According to a further aspect of the invention, a memory component is provided for storing a fault information in a fault state, particularly a fault information about a failure of light source, wherein particularly the memory component is configured to deactivate the simulation component in the fault state. Since in the disabled mode the control device is not able to test the light source directly when the simulation component is active, this could always result in positive test results of the functional test. However, when actually a fault of the light source occurs, this should be detected by the functional test. The memory component can overcome this issue. It can be activated by the electronics of the light source, e. g. by storing the fault information. In this state, the memory component deactivates the load so that the functional test provides a negative test result. The storage of the fault information can be performed limited in time.

It can be conceivable that the detection component is configured to actively detect a regular startup process of the control device for operating the light source by the input signal in the active mode so that the simulation component is deactivated when the startup process is detected. Therefore, the detection component can use a detection unit like a voltage divider or a Zener diode for a voltage evaluation of the input signal.

Preferably, it can be provided that the detection component has a detection unit for comparing a voltage specific for the input signal with a reference value, and for operating the simulation component depending on the comparison. For example, the reference value can be in the range from 4 to 6 V, particularly substantially 5 V.

Particularly when the input signal voltage is higher than the reference value, an active mode is detected. Then the simulation component can be deactivated.

According to another aspect of the invention, it is provided that the arrangement is electrically connected in parallel to the light source, and preferably integrated into the light source (particularly in the electronics of the light source). This enables to use the low resistance of the arrangement to mitigate the input signal for the light source. The arrangement can further be configured to work independently and/or autonomously from the control device. Preferably, the arrangement is only connected through the supply line (and particularly additionally through a ground line) with the control device and/or the light source, so that no additional lines (particularly wires) are needed.

The invention also relates to a method for operating at least one light source of a vehicle, particularly with at least one light-emitting diode, wherein the following steps are carried out, particularly one after the other or in any order:

Providing an electrical input signal from a control device of the vehicle,

Performing a detection of at least one of an active mode and a disabled mode of the light source, wherein in the disabled mode the input signal is used by a functional test for evaluating the light source, and in the active mode the light source is operated by the input signal,

Providing a load that is adapted to be evaluated by the functional test instead of the light source depending on the detection in the disabled mode of the light source.

Therefore, the method according to the invention can offer the same advantages as those described for the arrangement according to the invention. Furthermore, the method according to the invention can be suitable to operate the arrangement according to the invention.

In the following, preferred embodiments of the invention are described based on supportive figures. Thereby, the features described in the claims and in the description can be each single or in every combination essential for the invention. Elements bearing the same function and mode of action are assigned to the same reference signs. It is shown schematically:

FIG. 1 a schematic representation of an arrangement according to the invention, FIG. 2 another schematic representation of an arrangement according to the invention,

FIG. 3 another schematic representation of an arrangement according to the invention.

Figure 1 shows an arrangement 10 according to the invention for operating at least one light source 2 of a vehicle, particularly with at least one light-emitting diode. The arrangement 10 can be connected in parallel to a control device 1 of the vehicle and/or to the light source 2. The control device 1 can be suitable to operate the light source 2 as a lighting means of the vehicle. Flowever, the control device 1 can be configured to perform a functional test on a lighting means different from the light source 2.

As presented in Figure 2 and 3, the arrangement 10 can comprise: a supply line 20 for providing an electrical input signal 5 from the control device 1 of the vehicle, wherein the supply line 20 is suitable for transmitting the input signal 5 as a supply signal to the light source 2 in an active mode of the light source 2, and otherwise for providing the input signal 5 as a signal which is intended for the functional test of the light source 2 in a disabled mode of the light source 2,

a simulation component 30 for providing a load in the disabled mode, wherein the load is adapted to be evaluated by the functional test instead of the light source 2,

a detection component 40 for detecting at least one of the modes by using the input signal 5 and for operating the simulation component 30 depending on the detection.

The input signal 5 can particularly be provided by a voltage source 100 connected to a ground potential 110 and to a series resistor 101.

The detection component 40 can further have a detection unit 41 for comparing a voltage specific for the input signal 5 with a reference value, and for operating the simulation component 30 depending on the comparison. Furthermore, a memory component 50 can be provided for storing a fault information in a fault state, particularly a fault information about a failure of light source 2, wherein the memory component 50 is configured to deactivate the simulation component 30 in the fault state. The memory component 50 can particularly be activated by an electronics of the light source 2 by activation of the voltage source 100’. Then, a switching device 120 can be activated, which leads to a deactivation of the simulation component 30.

Figure 2 and 3 show exemplarily embodiments of the arrangement 10 according to the invention. According to Figure 2, the voltage source 100 provides an external supply voltage as input signal 5. For the functional test, the input signal 5 can be created through the series resistor 101 , R1 to limit the voltage below e. g. 5 V. The resistor R1 can have a resistance with a value in the range of 500 Ohm to 20 kOhm in the disabled mode. Flowever, in the active mode the input signal 5 has a much higher voltage. Therefore, the input signal 5 can be output without using the resistor R1 or with a very small resistor R1 (e.g. with a resistance below 1 Ohm). The resistors R2, R9, R5, R11 and R12 can be used as base leakage resistors for the safe operation of the arrangement. When the input signal 5 is turned on, a base current flows through transistor T1 and resistor R3 which turns on the transistor T1. Transistor T2 is turned on through the resistor R4. When the transistor T2 is activated, the load is activated and a load current flows through the collector resistor R6 and the emitter resistor R7. When the external series resistor R1 has a high resistance (in the disabled mode for the functional test) then only a small load current is formed since the voltage of the input signal 5 is kept low. If the external series resistor R1 has a low resistance (in the active mode) quickly the current through R7 increases and correspondingly also the voltage at R7 increases. This results in an activation of a transistor T6 through R8 and the diode D1. T6 in turn activates the transistor T5. The transistors T5, T6 work like a thyristor with a self-latching which can be reset only by a current interruption in these transistors. Due to this self-latching the transistor T3 is also active and the basis current of T3 is limited by the resistor R10. The active transistor T3 is connected in parallel to the basis-emitter-path of T1 and short-circuits this path. This causes a turn- off of the transistor T 1 and in consequence of that also T2 is turned off and no current flows through R6 and R7. The active mode is therefore detected by the detection component 40 (including R7 and T5) and in consequence the simulation component 30 (including T1 ) is deactivated.

Preferably R6 and R7 can have a very low resistance compared to the resistance of R1 and/or to the resistance of the light source. Particularly R6 and R7 can be at least 10 times or 100 times or 1000 times smaller than R1 or the resistance of the light source. Preferably particularly R6 and R7 from the detection unit 41.

Optionally the capacitor C1 and the high-resistance resistor R21 can be coupled to the electronics of the light source 2 and form a memory component 50. When the capacitor C1 is loaded by the voltage source 100’ the switching device 120 is activated and turns off the simulation component 30. Figure 3 shows another example, wherein the detection unit 41 is different from the embodiment shown in Figure 2. In Figure 3, a Zener diode D1 is used as detection unit 41 for detecting a voltage of the input signal 5 particularly above 5 V which indicates the active mode. Through the diode D1 the transistor T4 is activated, which in turn activates the transistor T3 and thereby deactivates T1. In contrast, in the disabled mode the input signal 5 for the functional test has a voltage below 2 V or the like. This voltage is not able to activate T4 by the diode D1. T4 can be part of the detection component 40.

Reference list

1 control device

2 light source

5 input signal

10 arrangement, circuit arrangement 20 supply line 30 simulation component

40 detection component

41 detection unit, voltage measurement unit

50 memory component

100 voltage source

101 series resistor

110 ground potential

120 switching device

100’ voltage source

Cn capacitor

Dn diode, zener diode

Rn resistors

Tn transistors

Claims

Patent claims

1. Arrangement (10) for operating at least one light source (2) of a vehicle,

particularly with at least one light-emitting diode, comprising:

- a supply line (20) for providing an electrical input signal (5) from a

control device (1 ) of the vehicle, wherein

the supply line (20) is suitable for transmitting the input signal (5) as a supply signal to the light source (2) in an active mode of the light source (2), and otherwise for providing the input signal (5) as a signal which is intended for a functional test of the light source (2) in a disabled mode of the light source (2),

- a simulation component (30) for providing a load in the disabled mode, wherein the load is adapted to be evaluated by the functional test instead of the light source (2),

- a detection component (40) for detecting at least one of the modes by using the input signal (5) and for operating the simulation component (30) depending on the detection.

2. Arrangement (10) according to claim 1 ,

characterised in

that the simulation component (30) is configured to prevent a sufficient energy supply of the light source (2) by the input signal (5) in the disabled mode, particularly by providing the load with a low resistance so that a flickering of the light source (2) by the input signal (5) is prevented.

3. Arrangement (10) according to claim 1 or 2,

characterised in

that the detection component (40) is configured to distinguish between a short pulse signal as the input signal (5) specific for the functional test and the supply signal with a voltage higher than the short pulse signal.

4. Arrangement (10) according to any of the preceding claims,

characterised in

that the detection component (40) is configured to switch between a low- resistance of the arrangement (10) in the disabled mode when the functional test is carried out by the control device (1 ) and a high-resistance of the arrangement (10) in the active mode.

5. Arrangement (10) according to any of the preceding claims,

characterised in

that a memory component (50) is provided for storing a fault information in a fault state, particularly a fault information about a failure of light source (2), wherein the memory component (50) is configured to deactivate the simulation component (30) in the fault state.

6. Arrangement (10) according to any of the preceding claims,

characterised in

that the detection component (40) is configured to actively detect a regular startup process of the control device (1 ) for operating the light source (2) by the input signal (5) in the active mode so that the simulation component (30) is deactivated when the startup process is detected.

7. Arrangement (10) according to any of the preceding claims, characterised in

that the detection component (40) has a detection unit (41 ) for comparing a voltage specific for the input signal (5) with a reference value, and for operating the simulation component (30) depending on the comparison.

8. Arrangement (10) according to any of the preceding claims,

characterised in

that the arrangement (10) is electrically connected in parallel to the light source (2), and preferably integrated in the light source (2).

9. Method for operating at least one light source (2) of a vehicle, particularly with at least one light-emitting diode, wherein the following steps are carried out:

- Providing an electrical input signal (5) from a control device (1 ) of the vehicle,

- Performing a detection of at least one of an active mode and a

disabled mode of the light source (2), wherein in the disabled mode the input signal (5) is used by a functional test for evaluating the light source (2), and in the active mode the light source (2) is operated by the input signal (5),

- Providing a load that is adapted to be evaluated by the functional test instead of the light source (2) depending on the detection in the disabled mode of the light source (2).

10. Method according to claim 9,

characterised in

that the method steps are performed by using an arrangement (10) according to any of the claims 1 to 8.