Automotive LED lighting module

Abstract

Embodiments include an automotive LED lighting module comprising an LED lamp comprising a number of light-emitting diodes; a first driver module configured to drive the LED lamp at a first DC voltage level (U_hi); a second driver module configured to drive the LED lamp at a second DC voltage level (U_lo), which second DC voltage level (U_lo) is lower than the first DC voltage level (U_hi); and a switch arrangement comprising an interface for connection to a two-level DC voltage supply (PS), and wherein the switch arrangement is configured to connect the first driver module to the LED lamp when the input voltage is at a first level (U_hi), and to connect the second driver module to the LED lamp when the input voltage level is at a second level (U_lo). Embodiments can further include an automotive lighting system of a vehicle, and a method of operating an automotive LED lighting system.

Claims

1. An automotive light emitting diode (LED) lighting module comprising: an LED lamp comprising a number of light-emitting diodes; a first driver module configured to drive the LED lamp at a first DC voltage level (U_hi); a second driver module configured to drive the LED lamp at a second DC voltage level (U_lo), which second DC voltage level (U_lo) is lower than the first DC voltage level (U_hi); a switch arrangement comprising an interface for connection to a two-level DC voltage supply (PS), and wherein the switch arrangement is configured to connect the first driver module to the LED lamp when the input voltage at the interface is at a first level (U_hi), and to connect the second driver module to the LED lamp when the input voltage level at the interface is at a second level (U_lo).

2. An automotive LED lighting module according to claim 1, wherein the interface for connection to the two-level DC voltage supply (PS) comprises a single positive terminal and a ground terminal.

3. An automotive LED lighting module according to claim 1, wherein the switch arrangement, the first driver module and the second driver module are incorporated in the LED lamp.

4. An automotive LED lighting module according to claim 1, wherein the first driver module is configured to drive the LED lamp at its rated output flux.

5. An automotive LED lighting module according to claim 1, wherein the second driver module is configured to drive the LED lamp, at most, 10% of its rated output flux.

6. An automotive LED lighting module according to claim 1, wherein the LED lamp comprises a number of red light-emitting diodes to provide a tail light function when the input voltage is at the first level (U_hi) and to provide a rear position light function when the input voltage level is at the second level (U_lo).

7. An automotive LED lighting module according to claim 1, wherein the LED lamp comprises a number of white-emitting LED light sources to provide a headlight function when the input voltage is at the first level (U_hi) and to provide a front position light function when the input voltage level is at the second level (U_lo).

8. An automotive LED lighting module according to claim 1, wherein the LED lamp comprises a number of yellow light-emitting diodes to provide an indicator function when the input voltage is at the first level (U_hi) and to provide a side position light function when the input voltage level is at the second level (U_lo).

9. An automotive lighting system of a vehicle, comprising a DC voltage supply (PS) configured to provide at least a first DC voltage level (U_hi) and a second DC voltage level (U_lo), which second DC voltage level (U_lo) is lower than the first DC voltage level (U_hi); a number of automotive LED lighting modules, wherein the LED lighting module includes an LED lamp comprising a number of LEDs, a first driver module configured to drive the LED lamp at a first DC voltage level (U_hi), a second driver module configured to drive the LED lamp at a second DC voltage level (U_lo), which second DC voltage level (U_lo) is lower than the first DC voltage level (U_hi), a switch arrangement comprising an interface for connection to a two-level DC voltage supply (PS), and wherein the switch arrangement is configured to connect the first driver module to the LED lamp when the input voltage at the interface is at a first level (U_hi), and to connect the second driver module to the LED lamp (10) when the input voltage level at the interface is at a second level (U_lo); and a controller configured to control the DC voltage supply (PS) according to an operating state of the vehicle.

10. An automotive lighting system according to claim 9, wherein the first DC voltage level (U_hi) is 13.5 V.

11. An automotive lighting system according to claim 9, wherein the second DC voltage level (U_lo) is less than 6 V.

12. An automotive lighting system according to claim 9, wherein the vehicle is equipped with a front lighting unit in which an automotive LED lighting module with white-emitting light emitting diode (LED) light sources is arranged to provide a front signaling function and a front position light function; and/or a rear lighting unit in which an automotive LED lighting module with red light-emitting diodes is arranged to provide rear signaling function and rear position light function; and/or a side lighting unit in which an automotive LED lighting module with yellow light-emitting diodes is arranged to provide indicator light function and side position light function.

13. A method of operating an automotive light emitting diode (LED) lighting system, which method comprises the steps of determining an operating state of a vehicle; controlling a DC voltage supply (PS) to provide a first DC voltage level (U_hi) to a specific automotive LED lighting module during a first operating state, wherein the LED lighting module includes an LED lamp comprising a number of LEDs, a first driver module configured to drive the LED lamp at a first DC voltage level (U_hi), a second driver module configured to drive the LED lamp at a second DC voltage level (U_lo), which second DC voltage level (U_lo) is lower than the first DC voltage level (U_hi), a switch arrangement comprising an interface for connection to a two-level DC voltage supply (PS), and wherein the switch arrangement is configured to connect the first driver module to the LED lamp when the input voltage at the interface is at a first level (U_hi), and to connect the second driver module to the LED lamp (10) when the input voltage level at the interface is at a second level (U_lo); and controlling the DC voltage supply (PS) to provide the second DC voltage level (U_lo) to that automotive LED lighting module during a second operating state.

14. A method of operating the automotive LED lighting module according to claim 13, further comprising connecting to the two-level DC voltage supply (PS) using a single positive terminal and a ground terminal.

15. A method of operating the automotive LED lighting module according to claim 13, further comprising incorporating the switch arrangement, the first driver module and the second driver module are incorporated in the LED lamp.

16. A method of operating the automotive LED lighting module according to claim 13, wherein the first driver module is configured to drive the LED lamp at its rated output flux.

17. A method of operating the automotive LED lighting module according to claim 13, further comprising driving, by the second driver module, the LED lamp at, at most, 10% of its rated output flux.

18. A method of operating the automotive LED lighting module according to claim 13, providing, by a number of red light-emitting diodes of the LED lamp, a tail light function when the input voltage is at the first level (U_hi) and to a rear position light function when the input voltage level is at the second level (U_lo).

19. A method of operating the automotive LED lighting module according to claim 13, further comprising providing, by a number of white-emitting LED light source of the LED lamp, a headlight function when the input voltage is at the first level (U_hi) and a front position light function when the input voltage level is at the second level (U_lo).

20. A method of operating the automotive LED lighting module according to claim 13, further comprising providing, by a number of yellow LEDs of the LED lamp, an indicator function when the input voltage is at the first level (U_hi) and to a side position light function when the input voltage level is at the second level (U_lo).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of an embodiment of an automotive LED lighting module;

(2) FIG. 2 is a schematic diagram of a further embodiment of an automotive LED lighting module;

(3) FIG. 3 is a schematic diagram of an embodiment of an automotive lighting system realised in an automobile;

(4) FIG. 4 shows a prior art automotive lighting system that uses a single LED lighting module to provide two functions.

(5) In the drawings, like numbers refer to like components throughout. Components in the diagrams are not necessarily drawn to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(6) FIG. 1 is a schematic diagram of an embodiment of the automotive LED lighting module 1. The lighting module 1 comprises an LED lamp 10 with one or more light-emitting diodes 100, a first driver module 11 configured to drive the LED lamp 10 at a first DC voltage level U_hi, and a second driver module 12 configured to drive the LED lamp 10 at a second DC voltage level U_lo, which can be at a level lower than any low transients that may appear on the first DC voltage level U_hi. The lighting module 1 further comprises a switch arrangement 13, 130 connected across an interface 151, 152. The interface can be in the form of a pair of input pins 151, 152 so that the LED lighting module 1 can be inserted into a suitable connector for connection to a DC voltage supply PS that delivers a voltage U_hi, U_lo according to a desired light output level. The switch arrangement 13, 130 is configured to connect the first driver module 11 to the LED lamp 10 when the input voltage is at a first level U_hi, and to connect the second driver module 12 to the LED lamp 10 when the voltage is at a second level U_lo. This could be done in any number of ways. For example, the switch arrangement may comprise a DC level sensing circuit 13 which controls a multiplexer 130 according to the voltage sensed across the inputs 151, 152. When the high voltage level U_hi is sensed, the switch arrangement 13, 130 routes the output of the high-level driver module 11 to the LED lamp 10; when the low voltage level U_lo is sensed, the switch arrangement 13, 130 routes the output of the low-level driver module 12 to the LED lamp 10. A driver module 11, 12 may be assumed to comprise a suitable driver architecture such as a resistor network, or a linear driver comprising active components, and a driver module 11, 12 is realised to limit the LED current I.sub.11, I.sub.12 to a defined level so that the LED lamp 10 is driven at a suitable constant current. The first driver module 11 will ensure that the LED lamp 10 is driven with a higher current I.sub.11, while the second driver module 12 will ensure that the LED lamp 10 is driven with a lower current I.sub.12. In the diagram, everything to the right of the interface 151, 152 may be realised inside a housing of the LED module 1. In the embodiment of FIG. 1 the driver modules 11, 12 are shown as functionally separate blocks, each with its own linear driver and control resistor, and the multiplexer 130 effectively connects the output of the desired driver module 11, 12 to the LED lamp 10.

(7) FIG. 2 shows an alternative embodiment in which a single linear driver 102 may be used instead, with two distinct control resistors R.sub.11, R.sub.12 to determine the desired high and low current levels I.sub.11, I.sub.12. In this embodiment, the high-level driver module 11 comprises the linear driver 102 and the first resistor R.sub.11, and the low-level driver module 12 comprises the linear driver 102 and the second resistor R.sub.12. The driver modules 11, 12 effectively share the single linear driver 102. The multiplexer 130 is arranged to select the high current I.sub.11 or the low current I.sub.12 as desired.

(8) FIG. 3 is a very simplified schematic diagram of an embodiment of the automotive lighting system 2 realised in an automobile 3 (indicated only very schematically be the dotted line). The automobile is equipped with several instances of the automotive LED lighting module 1, all of which are powered by a DC voltage supply PS. In this embodiment, instances of the automotive LED lighting module 1 are installed in front lighting units 31, rear lighting units 32, and side lighting units 33. The power supply PS provides power to a controller 20 or body control unit which provides each lighting unit 31, 32, 33 with the appropriate voltage for the applicable operating state of the automobile. For example, when the automobile 3 is being driven, the controller 20 ensures that the voltage U 31 provided to the LED lighting modules 1 of the front lighting units 31 is the high voltage level U_hi referred to in FIG. 1; the voltage U_32 provided to the LED lighting modules 1 of the rear lighting units 32 is the high voltage level U_hi referred to in FIG. 1; and the voltage U_33 provided to the LED lighting modules 1 of the side lighting units 33 is the low voltage level U_lo referred to in FIG. 1. When the automobile 3 is being turned left or right, the controller 20 ensures that the voltage U_33 provided to the LED lighting modules 1 of the side lighting units 33 alternates at a suitable rate between the high voltage level U_hi and the low voltage level U_lo; when the automobile is parked, the controller 20 ensures that the voltage provided to each lighting unit 31, 32, 33 is the low voltage level U_lo referred to in FIG. 1 to activate the position-light function in each case.

(9) FIG. 4 shows a prior art approach that uses a single LED lighting module 4 that uses a single LED lamp 40 to provide two functions, e.g. a LYS lamp 40 that acts as indicator light when the vehicle is turning, as well as a side position light when the vehicle is not turning. To achieve this, the prior art approach requires a PWM module 42 that is actuated by a control signal 420 originating from a controller (not shown in the diagram) when the LED lamp 40 is to deliver less than its rated flux. By appropriate control of a switching module 43, the driver 40 of the LYS lamp 40 is supplied with the usual voltage level U_hi to deliver 100% rated flux when the lamp 40 is to be used as an indicator light, or with the PWM modulated voltage U_pwm when the LED lamp 40 is to be used as a side position light.

(10) Although embodiments have been disclosed in the form of embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of embodiments. For example, although the automotive LED lighting module has been described to incorporate two driver modules and a switch module in the module housing, it is of course possible to realise the driver modules and switch module independently of an LED lamp. In such an embodiment, a single set of two driver modules and a switch module could be realised to drive a number of LED lamps, for example a number of LED lamps installed in spatially separate regions in a vehicle.

(11) For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements.