Lighting assembly for supplying power to an increased number of series-connected lighting units

Abstract

The invention relates to a lighting assembly (100) comprising at least a first lighting module (130.1) having a plurality of sequences (135) of lighting units (140) in series. A power source (120) is configured to power at least the first lighting module and is configured to power a maximum number N of lighting units simultaneously. A command module (180) is configured to: - determine the sequence to be activated and a number Na of lighting units contained in the sequence to be activated; - if Na is greater than N, group the sequence to be activated into at least two groups, each group containing less than N lighting units; - cyclically and sequentially power each of the groups based on a cycle period, the cycle period being such that an observer perceives that at least two groups are activated simultaneously.

Description

Technical Field

[0001] The present invention relates to the technical field of control of lighting modules. In particular, but not limited to, it relates to a lighting assembly including a lighting module having a sequence (continuous) of lighting units and a control module for controlling the power supply of the sequence of lighting modules.

Summary of the Invention

[0002] It is advantageous when the lighting assembly includes a plurality of series-connected LEDs that cannot be simultaneously powered by a single power source.

[0003] In motor vehicles, lighting assemblies generally include lighting units assigned to specific lighting functions and / or signaling functions. In the following, the term lighting function is used to refer to both lighting functions and signaling functions.

[0004] U.S. Patent US8525415B2 discloses a system that uses time sharing to supply power by a common power source to different lighting functions. However, those functions are powered in parallel, and the number of LEDs within one function is limited by the capacity of the power source.

[0005] Therefore, in this architecture, the number of LEDs per function is limited by the capacity of the power source.

[0006] The present invention improves this situation.

[0007] For this purpose, a first aspect of the invention relates to a lighting assembly including: - A first lighting module configured to perform at least a first lighting function and comprising a plurality of sequences of at least one lighting unit in series; - A power source configured to supply power to at least the first lighting module, the power source being configured to supply power to a maximum number N of lighting units simultaneously; and - A command module configured to control the activation and deactivation of each of the sequences of the lighting unit.

[0008] The command module is configured as follows: - Determine the sequence to be activated and the number Na of lighting units included in the sequence to be activated; - If Na is greater than N, group the sequence to be activated into at least two groups, each group including less than N lighting units; - Supply power to each group periodically and continuously based on a cycle period, the cycle period being a period such that an observer perceives that at least two groups are operating simultaneously.

[0009] Thus, the invention makes it possible to overcome the drawbacks of the prior art. In fact, in the prior art, time sharing is based on the number of functions, while the present invention proposes to group sequences of less than N LEDs within the same function or between different functions, thereby making it possible for a number of series-connected lighting units greater than N to be perceived by an observer as being switched on simultaneously.

[0010] According to some embodiments, the assembly may further include at least a second lighting module configured to perform at least a second lighting function. The second lighting module may include a plurality of sequences, each sequence including at least one lighting unit.

[0011] Thereby, it is possible to supply power to a plurality of functions in series. The plurality of lighting functions can be perceived as being activated simultaneously, and each function can correspond to more than N lighting units as required.

[0012] Supplementally, each group may include a sequence of the same lighting module.

[0013] This improves the visual recognition of each lighting function by the user.

[0014] Alternatively, at least one group may include a sequence of the first lighting module and a sequence of the second lighting module.

[0015] This improves the flexibility of the lighting assembly according to the invention, enables the use of a minimum number of groups, thereby facilitating the control of the sequence and reducing the power loss due to time sharing.

[0016] According to some embodiments, the second lighting function may be a daytime lighting function or a position lighting function.

[0017] Thereby, the visibility of the vehicle including the lighting assembly can be improved for other users on the road.

[0018] In addition, the second lighting module is configured to perform both a daytime lighting function and a position lighting function.

[0019] Thereby, two functions can be performed using the same lighting module, thereby reducing the size of the lighting assembly.

[0020] According to some embodiments, the lighting assembly may include a function switching unit in parallel with the second lighting module, and the command module may be configured to close the switching unit to deactivate the second lighting module.

[0021] Thereby, the control when the second function module is off can be simplified.

[0022] In addition, the second lighting module and the function switching unit may be located on the low side compared to the first lighting module.

[0023] As a result, a standard controller having a generally low side switch can be used.

[0024] According to some embodiments, the first lighting function may be a turn indicator, TI, function.

[0025] This function is particularly adapted to be controlled using a sequence of switching units in series.

[0026] According to some embodiments, the assembly may further include switching units in parallel with each of the sequence of lighting units, and the command module may be configured to control the opening and closing of the switching units to activate and deactivate the sequence of lighting units.

[0027] As a result, the activation and deactivation of the sequence of lighting units can be easily controlled.

[0028] Supplementally, each group may be powered using pulse width modulation, PWM, control of the switching unit in parallel with the sequence of the group, and the command module may be configured to set the duty cycle of the PWM control based on the number of groups. As a result, time sharing using PWM can be performed. Generally, the command module integrates a microprocessor configured to execute PWM.

[0029] Further supplementally, when the activated sequence is grouped into two groups, the command module is configured to set the duty cycle of the PWM control to 40% - 50% or 43% - 47%.

[0030] As a result, a good trade-off is ensured between reduction of power loss by time sharing and avoidance of abrupt opening and closing of the switching unit that can cause a surge current damaging the lighting unit.

[0031] According to some embodiments, the command module may be configured to receive an input command, and the sequence to be actuated may be determined based on the input command.

[0032] A second aspect of the invention relates to a method of powering at least a first lighting module, the first lighting module being configured to perform a first lighting function and including a plurality of sequences of at least one lighting unit in series. The maximum number N of lighting units that can be powered simultaneously by the power supply is predetermined.

[0033] The method includes the following steps: - Determine the sequence to be actuated and the number Na of lighting units included in the sequence to be actuated; - If Na is greater than N, group the sequence to be actuated into at least two groups, each group including less than N lighting units; - Periodically and continuously supply power to each group based on a cycle period, the cycle period being a period such that an observer perceives that at least two groups are actuated simultaneously.

[0034] A third aspect of the invention relates to a computer program including instructions for implementing the method according to the second aspect of the invention when the instructions are executed by a processor.

Brief Description of the Drawings

[0035] Other features and advantages of the invention will become apparent from the description and the accompanying drawings detailed below, in the accompanying drawings:

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0036] FIG. 1 shows a lighting assembly 100 according to some embodiments of the invention.

[0037] The lighting assembly includes a power source 120 that supplies power in series to a first lighting module 130.1 and a second lighting module 130.2. Examples of the two lighting modules are given for illustrative purposes only. More generally, the lighting assembly 100 may include any number k of lighting modules, where k is an integer greater than or equal to 1.

[0038] The power source 120 may include a converter that converts the source power into output power applied to the lighting modules. The power source 120 may be a voltage source or a current source.

[0039] The power source 120 preferably provides a DC voltage according to the invention.

[0040] For this purpose, the voltage source 120 may include a DC voltage source and a DC / DC converter. Alternatively, the voltage source 120 may include an AC voltage source and an AC / DC converter.

[0041] The first lighting module 130.1 is arranged to perform a first lighting function, and the second lighting module 130.2 is arranged to perform a second lighting function. The first lighting module 130.1 and the second lighting module 130.2 are connected in series.

[0042] There is no restriction on the lighting function executed by the lighting module, and it can be selected from the following: - High beam HB function; - Low beam LB function; - Daytime running lighting DRL function; - Position lighting PL function; - Turn indicator TI function; - Other lighting functions.

[0043] In the following, for the purpose of illustration only, it is considered that the first lighting module 130.1 is arranged to execute the TI function, and the second lighting module 130.2 function is arranged to execute the DRL function and / or the PL function. According to one embodiment, the second lighting module 130.2 is arranged to execute both the DRL function and the PL function.

[0044] To execute the first lighting function, the first lighting module 130.1 may include six sequences 135.1, 135.2, 135.3, 135.4, 135.5, 135.6 of the lighting unit 140. As shown in FIG. 1, each sequence 135 may include three lighting units 140. However, there are no restrictions on the number n1 of sequences and the number k1 of lighting units per sequence of the first lighting module 130.1. Alternatively, the number of lighting units 140 per sequence may vary such that each sequence of index i, where i varies from 1 to n1, may include the number k(1, i) of lighting units 140.

[0045] According to the TI function, the sequences 135.1 to 135.6 may be continuously powered one after another.

[0046] To execute the second lighting function, the second lighting module 130.2 may include six sequences 136.1, 136.2, 136.3, 136.4, 136.5, 136.6 of the lighting unit 140. As shown in FIG. 1, each sequence 136 may include three lighting units 140. However, the number n2 of sequences and the number k2 of lighting units per sequence of the second lighting module 130.2 are not limited. Alternatively, the number of lighting units 140 per sequence may vary such that each sequence j, where j varies from 1 to n2, may include the number k(2,j) of lighting units 140.

[0047] The first lighting module and the second lighting module may be integrated into the headlamp.

[0048] The lighting unit 140 may be any technology that can emit light when a voltage is applied thereto. In the following, an example where the lighting unit is a diode such as an LED will be considered for illustrative purposes only. Therefore, without departing from the fact that the lighting unit may include other technologies than LEDs, in the following < <led>The expression "> " is used to replace <<lighting unit>>.

[0049] To control the activation / deactivation of Sequence 135, each Sequence 135.i is connected in parallel with Switching Unit 150.i. Similarly, to control the activation / deactivation of Sequence 136, each Sequence 136.j is connected in parallel with Switching Unit 151.j.

[0050] There is no limitation on the technology used for the switching unit, and it can be, for example, any transistor configured to perform a switching function. For example, the switching unit may be an N-MOS. Alternatively, the switching unit may be a P-MOS.

[0051] Each switching unit may be controlled by a command module 180 configured to issue a command signal for opening and closing switching units 150 and 151.

[0052] The lighting assembly 100 may further include an optional function switching unit 152, such as a low-side switching LSS unit 152, configured to bypass the second lighting module 130.2 to deactivate the DRL / PL function when the LSS unit 152 is closed. The command module 180 may control the LSS unit 152.

[0053] When the LEDs 140 are connected in series, the maximum number of LEDs 140 can be powered simultaneously. Let the maximum number of LEDs that can be powered by the power supply 120 be denoted as N. The number N is determined by the power supply 120.

[0054] In the following, for the purpose of explanation only, it is considered that N is equal to 15.

[0055] For this reason, if the TI function and the DRL / PL function are such that they turn off more than 15 LEDs, the power supply 120 cannot supply power to the lighting function.

[0056] To overcome this, when the number of LEDs activated to perform the first and / or second lighting functions is greater than the maximum number N, the command module 180 is configured as follows: - Group the sequence of LEDs to be activated into several groups, whereby each group contains fewer LEDs than the maximum number N; - Periodically and continuously supply power to each of the groups. The cycle period between two power supplies of the same group is such that an observer would perceive them as being activated simultaneously.

[0057] Thereby, more than N series-connected LEDs can be lit periodically and continuously, such that they are perceived by an external user as being lit simultaneously.

[0058] According to the first embodiment, the sequences of the plurality of groups of LEDs perform the same function. This is the case, for example, when the command module 180 decides to turn on six sequences of the LEDs of the first lighting module 130.1. In this case, 18 LEDs will be lit, which is greater than N = 15 LEDs. Thus, the command module 180 can activate the first group of three sequences 135.1, 135.2, 135.3, and then the second group of three sequences 135.4, 135.5, 135.6, periodically and continuously. Thus, 9 LEDs are lit at a single point in time and can be powered by the power supply 120.

[0059] According to the second embodiment, the sequences of the plurality of groups of LEDs are divided between at least two lighting modules. Within one group of sequences, the sequences may belong to the same lighting module or to two different lighting modules.

[0060] For example, it is determined that three sequences 135.1, 135.2, 135.3 of the first lighting module 130.1 and six sequences 136.1, 136.2, 136.3, 136.4, 136.5, 136.6 of the second lighting module 130.2 are to be actuated by the command module 180. Thus, it is necessary to light 27 LEDs: for this purpose, the command unit 180 may periodically and continuously light a first group including three sequences 135.1, 135.2 and 135.3 and a second group including six sequences 136.1, 136.2, 136.3, 136.4, 136.5, 136.6. Alternatively, the first group may include three sequences 135.1, 135.2, 135.3 and 136.1, and the second group may include five sequences 136.2, 136.3, 136.4, 136.5, 136.5.

[0061] The above specific examples are given for illustrative purposes only.

[0062] FIG. 2 shows a time diagram for explaining time sharing between a sequence of a first group of lighting units and a sequence of a second group of lighting units according to the invention.

[0063] The time diagram shows how the command module 180 alternately switches between the sequences of the first group and the sequences of the second group. For this purpose, three time slots 201.1, 201.2 and 201.3 are allocated for power supply to the sequences of the first group, and three time slots 202.1, 202.2 and 202.3 are allocated for power supply to the sequences of the second group.

[0064] Two consecutive time slots assigned to the same group are separated by a period 200, which is such that an external observer's eye perceives that the first and second groups are operating simultaneously over a period 203. Thus, an external user cannot distinguish which group of the LED sequence is lit at a given time.

[0065] For example, the power supply frequency of a given group obtained by the reciprocal of the period 200 may be greater than 100 Hz, for example included in 100 - 300 Hz.

[0066] To achieve this, the command module 180 may perform pulse width modulation on the switches 150 - 151 corresponding to the sequence of the first group and the switches 150 - 151 corresponding to the sequence of the second group. For example, it is possible to apply a duty cycle of less than 50% to each of the two groups. Preferably, the duty cycle applied to each group is equal to 45%, which can prevent the switching unit 150 from being abruptly opened or closed to avoid surge currents that can degrade the LED 140.

[0067] Figure 3 shows a time diagram explaining time sharing between three groups of sequences of the lighting unit according to the invention.

[0068] The time diagram shows how the command module 180 alternately switches between the sequences of the first group, the second group, and the third group. For this purpose, over a duration 303, three time slots 301.1, 301.2, and 301.3 are periodically assigned to supply power to the sequence of the first group, three time slots 302.1, 302.2, and 302.3 are periodically assigned to supply power to the sequence of the second group, and three time slots 303.1, 303.2, 303.3 are periodically assigned to supply power to the sequence of the third group.

[0069] Two consecutive time slots assigned to the same group are separated from each other by a period 300, which is such that an external observer would see the first and second groups operating simultaneously over a period 303. Thus, the external observer cannot distinguish which group of the LED sequence is lit at a given time. The period 300 may be equal to the above period 200. In that case, the time slots 301, 302 and 303 are shorter than the time slots 201, 202.

[0070] For example, the power supply frequency of a given group obtained by the reciprocal of the period 200 may be greater than 100 Hz, for example included in 100 - 300 Hz.

[0071] To achieve this, the command module 180 may perform pulse width modulation on the switches 150 - 151 corresponding to the sequence of the first group, the switches 150 - 151 corresponding to the sequence of the second group, and the switches 150 - 151 corresponding to the sequence of the third group. For example, it is possible to apply a duty cycle of less than 33% to each of the two groups. Preferably, the duty cycle applied to each group is equal to 30%, which can prevent the switching unit 150 from being abruptly closed or opened to avoid the surge current that may deteriorate the LED 140.

[0072] The decision as to which sequence to activate at a given time may be made by the command module 180 based on the input command.

[0073] For this purpose, the command module 180 can be configured as follows: - Receive an input command; - Based on the input command, determine the sequences 135 and 136 to be turned on, hereinafter named the active sequences; - Determine the number Na of LEDs in the active sequence; - Compare Na with the maximum number N; - If Na is less than or equal to N, - The others are as described above: - Group the sequences of LEDs to be activated into several groups, such that each group contains fewer LEDs than the maximum number N; - Periodically and continuously supply power to each of the groups, and the period between two power supplies to the same group is such that an external observer can see the groups being activated simultaneously.

[0074] Figure 4 is a flowchart showing the steps of a method according to some embodiments of the invention, implemented in the command module 180.

[0075] In step 400, the command module 180 receives an input command. The input command can be received from an external unit such as a vehicle's centralized control system following an input by the vehicle's driver. However, there is no limitation on the input command, and the input command can alternatively be provided automatically.

[0076] In step 401, based on the input command, the command module 180 determines sequences 135 and 136 to be turned on, named the active sequence. As described above, the active sequence may be a sequence from a specific lighting module 130.1 or 130.2, or a sequence to at least two different lighting modules.

[0077] In step 402, the command module 180 determines the number Na of LEDs in the active sequence.

[0078] In step 403, the command module 180 compares that number Na with the maximum number N of LEDs in series that can be powered simultaneously by the power supply 120.

[0079] In step 404, if Na is less than or equal to N, the command module 180 activates the active sequence by closing the corresponding switching unit 150.

[0080] In step 405, if Na is greater than N, the command module 180 groups the sequence of LEDs to be activated into several groups, such that each group contains less than the maximum number N of LEDs. As described above, each group may contain a sequence of the same lighting module 130 or may contain a sequence from different lighting modules 130.

[0081] In step 406, the command module 180 powers each of the groups sequentially, and the cycle period between two power supplies of the same group is such that an external observer would see those groups being activated simultaneously. By controlling the switching units corresponding to the sequences of each group, those groups are powered sequentially. In contrast to step 404, time sharing is used to power more than N LEDs over a given duration.

[0082] FIG. 5 shows the structure of the command module 180 according to an embodiment of the invention.

[0083] The command module 180 includes a memory 504, such as a random access memory, RAM, read only memory (ROM), or other memory (such as a flash EEPROM), and a processor 502 configured to communicate unidirectionally or bidirectionally via one or more buses. Alternatively, the memory 504 may include several memories of a specified type staying therein.

[0084] The memory 504 is configured to store the association between the output of the command module and the switching units 150, 151, either permanently or temporarily. It may also store the input commands received from an external entity.

[0085] The memory includes instructions for executing the steps of the method shown in FIG. 4.

[0086] The processor 502 is configured to execute these instructions.

[0087] The processor may be a microcontroller designed and configured to execute the steps of the method as described in FIG. 4.

[0088] The command module 180 may further include an input interface 501 and an output interface 503. The input interface 501 may be configured to receive data from an external entity such as a central control unit. Such data may be, for example, an input command that can be used by the command module 180 to determine which sequence is activated. The output interface 503 may include a plurality of pins, and each pin is configured to issue a control signal for controlling the opening and closing of the switching units 150, 151, or 152.

[0089] The present invention is not limited to the embodiments described above as examples: it extends to other alternatives.< / led>

Claims

1. A lighting assembly (100), comprising: - at least a first lighting module configured to perform a first lighting function and including a plurality of sequences (135) of at least one lighting unit (140) in series; - a power supply (120) configured to supply power to at least the first lighting module, the power supply being configured to supply power to a maximum number N of lighting units simultaneously; - a command module (180) configured to control the activation and deactivation of each of the sequences of lighting units; The command module is - to determine an activated sequence and the number Na of lighting units included in the activated sequence; - if Na is greater than N, to group the activated sequence into at least two groups, each group including less than N lighting units; - to supply power to each of the groups periodically and continuously based on a cycle period; configured, wherein the cycle period is a period such that an external observer perceives that the at least two groups are activated simultaneously; characterized lighting assembly (100).

2. The assembly according to claim 1, further comprising at least a second lighting module (130.2) configured to perform at least a second lighting function, the second lighting module including a plurality of sequences, each sequence including at least one lighting unit.

3. The assembly according to claim 2, wherein each group includes sequences (135; 136) of the same lighting module (130.1; 130.2).

4. The assembly according to claim 2, wherein at least one group includes sequences (135; 136) of the first lighting module (130.1) and the second lighting module (130.2).

5. The assembly according to any one of claims 2 to 4, wherein the second lighting function is a daytime lighting function or a position lighting function.

6. The assembly according to claim 5, wherein the second lighting module (130.2) is configured to perform both a daytime lighting function and a position lighting function.

7. The assembly according to any one of claims 2 to 6 further comprises a function switching unit (152) in parallel with the second lighting module (130.2), and the command module (180) is configured to close the function switching unit to stop the operation of the second lighting module.

8. The assembly according to claim 7, wherein the second lighting module (130.2) and the function switching unit are in a lower side position compared to the first lighting module (130.1).

9. The assembly according to any one of claims 1 to 8, wherein the first lighting function is a turn indicator function.

10. The assembly according to any one of claims 1 to 9 further comprises a switching unit (150; 151) in parallel with each of the sequences of the lighting unit, and the command module (180) is configured to control the opening and closing of the switching unit to operate and stop the operation of the sequence (135; 136) of the lighting unit.

11. Each group is powered using PWM control of the switching unit (150; 151) in parallel with the sequence of the group, and the command module (180) is configured to set the duty cycle of the PWM control based on the number of groups.

12. The assembly according to claim 11, wherein when the sequence (135; 136) to be operated is grouped into two groups, the command module (180) is configured to set the duty cycle of the PWM control to 40% to 50% or 43% to 47%.

13. The assembly according to any one of claims 1 to 12, wherein the command module (180) is configured to receive an input command, and the sequence to be operated is determined based on the input command.

14. A method for supplying power to at least a first lighting module (130.1) configured to execute a first lighting function and including a plurality of sequences of at least one lighting unit in series, wherein the maximum number N of lighting units that can be powered simultaneously by the power supply is predetermined, and the method is characterized by the following steps: - Determine an actuated sequence and the number Na of lighting units included in the actuated sequence (401; 402); - If Na is greater than N, group the actuated sequence into at least two groups (405), each group including less than N lighting units; - Periodically and continuously supply power to each of the groups based on a cycle period (406), the cycle period being a period such that an observer perceives that the at least two groups are actuated simultaneously, Method.

15. A computer program including instructions which, when executed by a processor, implement the method according to claim 14.

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