DE102015222504A1 - Lighting device for a motor vehicle - Google Patents

Abstract

The invention relates to a lighting device for a motor vehicle, comprising one or more processing modules (1) and an internal data bus (2) and a plurality of LED units (3). The internal data bus (2) is an SPI bus or a differential data bus, wherein a differential data bus encodes digital data about a voltage difference between two lines. A respective processing module (1) is associated with a plurality of LED units (3) of the plurality of LED units (3) and the respective processing module (1) is coupled to the associated LED units (3) via the internal data bus (2) , The associated LED units (3) each comprise one or more LEDs (301, 302, 303) and an integrated circuit (4) and are connected to a power supply (5) for the one or more LEDs (301, 302, 303). The respective processing module (1) is adapted for coupling to a motor vehicle data bus (6) to receive first digital control commands for operating the lighting device from the motor vehicle data bus (6) and to the internal data bus (2) as second digital control commands give. The associated LED units (3) are adapted to supply their LEDs (3) with power from the power supply (5) based on the second digital control commands on the internal data bus (2) by means of the integrated circuits (4).

Description

The invention relates to a lighting device for a motor vehicle.

From the prior art, it is known to use LEDs for lighting devices in motor vehicles in various versions. The individual LEDs (monochrome, RGB, RGBW) are usually controlled by LED drivers. For this purpose, a module is used with a microprocessor, on the one hand takes over communication with a motor vehicle data bus and on the other drives the LEDs, usually via PWM outputs. As a motor vehicle data bus is often the so-called. LIN bus (LIN = Local Interconnect Network) is used. In this type of control there is the problem that only a certain maximum number of LEDs can be controlled.

Also known from the prior art are novel LED units which have an integrated circuit. In these LED units, the LEDs and the integrated circuit are housed in a common housing, whereby a high packing density can be achieved. The individual LED units are controlled by a data stream. To date, there are no approaches to how these LED units can be coupled to a motor vehicle data bus for use as a motor vehicle lighting device.

The object of the invention is to provide a lighting device for a motor vehicle, which allows the coupling of a large number of LED units to a motor vehicle data bus.

This object is achieved by the lighting device according to claim 1. Further developments of the invention are defined in the dependent claims.

The lighting device according to the invention is intended for a motor vehicle, in particular for a car and possibly also for a truck, and comprises one or more processing modules as well as an internal data bus and a multiplicity of LED units. The internal data bus is an SPI (Serial Protocol Interface) data bus, which is known per se from the prior art. Alternatively, the internal data bus may also be a differential data bus, wherein a differential data bus is characterized in that digital data is encoded via a voltage difference between two lines. In a preferred variant, the APIX bus known per se (APIX = Automotive Pixel Link) is used as the differential data bus. APIX is a bi-directional bus with additional sidebands. To control the LEDs you need only a part of it, so a uni-directional bus.

In the lighting device according to the invention, a plurality of LED units of the plurality of LED units are assigned to a respective processing module and the respective processing module is coupled to the associated LED units via the internal data bus. The internal data bus is thus provided for communication between the respective processing modules and the associated LED units.

The LED units associated with a respective processing module each include one or more LEDs and an integrated circuit. The LED units are connected to a power supply for the LED or LEDs. The respective processing module is adapted to be coupled to a motor vehicle data bus for receiving first digital control commands for operating the lighting device from the motor vehicle data bus and for providing as second digital control commands to the internal data bus. Further, the LED units associated with a respective processing module are configured to supply power to their LEDs from the power supply based on the second digital control commands on the internal data bus via the integrated circuits.

With the lighting device according to the invention, a suitable conversion of control commands on a motor vehicle data bus into control commands on an internal data bus in the form of an SPI bus or a differential data bus is achieved. In this way, the driving of a large number of LED units can be performed without being limited to a maximum number. In contrast, in the case of control purely via a motor vehicle data bus in the form of a LIN bus, the number of LED units is usually limited to 16-24 due to line capacitances.

In a particularly preferred embodiment of the lighting device according to the invention, the processing module or modules are arranged for coupling to a motor vehicle data bus in the form of the LIN bus already mentioned above. Alternatively or additionally, as a motor vehicle data bus and a CAN bus (CAN = Controller Area Network) can be used.

In a further embodiment of the lighting device according to the invention, the internal data bus is an SPI bus and the processing module (s) are configured such that the first digital control signals are applied to the SPI bus by means of software SPI and / or hardware SPI become. The software SPI method is well known in the art and, by means of a program library, allows to create an executable program on the corresponding processing module that configures each pin of the processing module as an SPI pin for connection to SPI bus lines can. In other words, when using software SPI, conventional I / O pins are configured as SPI pins. In contrast, when using hardware SPI, dedicated pins of the processing module are provided for connection to the SPI bus.

In a further, particularly preferred variant of the illumination device according to the invention, a respective processing module of at least a portion of the processing modules is coupled to the internal data bus such that one or more, only the one or more, LED units assigned to several different (ie disjunctive) subsets of LED units respective subset associated data lines of the internal data bus are connected to the respective processing module to transmit the second digital control commands over this. In other words, the data transmission takes place on the internal data bus via a plurality of different data lines for corresponding subsets of LED units. As a result, the number of controllable LED units can be further increased. Preferably, this embodiment of the invention is combined with the software SPI method described above, in which any pins of the processing module are used to transfer data to the SPI bus.

In a further preferred embodiment, the lighting device comprises only a single processing module for all LED units of the plurality of LED units. As a result, a particularly compact construction of the lighting device is achieved.

Depending on the embodiment of the lighting device according to the invention, one or more of the LED units of the plurality of LED units can have RGB LED units with a red, green and blue LED and / or RGBW LED units with a red, green, blue and be white LED. Optionally, one or more of the LED units of the plurality of LED units may also be configured as white light LED units with a white LED. Further, one or more of the LED units of the plurality of LED units may also be single color LED units having a single color LED (e.g., red, green, or blue).

In a further variant of the lighting device according to the invention, one or more of the LED units of the plurality of LED units are each configured such that the integrated circuit and the one or more LEDs of the respective LED unit are integrated in a common housing. Thus, particularly compact LED units are used in the lighting device according to the invention, whereby their size can be reduced. In a particularly preferred variant, LED units of the type APA10x and / or of the types WS281x, SK691x, PL982x and derivatives of these types are used. These types of LED units are known per se from the prior art and allow their stringing together with a very high packing density.

In a further embodiment of the lighting device according to the invention, one or more of the LED units of the plurality of LED units are each configured to supply power to the LED or LEDs of the respective LED unit from the power supply via PWM modulation. Alternatively or additionally, there is also the possibility that one or more of the LED units of the plurality of LED units are each configured to supply power to the LED or LEDs of the respective LED unit via the setting of variable current levels.

Depending on the configuration, the lighting device according to the invention may be provided for different purposes in the vehicle. In particular, the lighting device may be an interior lighting in the interior of the vehicle. Nevertheless, there is also the possibility that the lighting device is an outdoor lighting on the outside of the motor vehicle.

In addition to the lighting device just described, the invention relates to a motor vehicle, in particular a car or optionally also a truck, which comprises one or more of the lighting devices according to the invention or preferred variants of these lighting devices.

An embodiment of the invention will be described below in detail with reference to the accompanying drawings.

Show it:

1 a schematic representation of an embodiment of a lighting device according to the invention; and

2 a detailed view of a LED unit 1 ,

In the following, an embodiment of the invention will be described with reference to a lighting device which comprises a plurality of LED units arranged on a belt as lighting means. These LED units are in 1 with the reference number 3 designated. The individual LEDs of the LED units are denoted by the reference numerals 301 . 302 and 303 designated. The LED 301 is a red LED, the LED 302 a green LED and the LED 303 a blue LED. Each LED unit 3 contains an integrated circuit, which by reference numerals 4 is designated. With the LED units 3 These are preferably LED units of the type APA10x or of the type WS281x, SK691x, PL982x, which are very compact. In particular, in these LED units, the LEDs and the integrated circuit are housed in a common housing. With the ribbon-shaped LED units, a very high packing density can be achieved (depending on the housing form from 144 to 367 LEDs / m).

The individual LED units 3 are driven via a digital data stream in the form of a bit stream, which is generated by means of an internal data bus 2 (ie, an internally provided in the lighting device data bus) is supplied to the individual LED units. The internal data bus in the embodiment described here is an SPI bus with a line CL for the clock and a line DL for the bit stream. In addition, two power lines L1 and L2 are provided which are connected to a DC power supply 5 are connected. Based on the bit stream received via the data line DL, a PWM modulation of the individual LEDs takes place 301 to 303 supplied current to thereby drive the LEDs according to the bit stream on the data line DL.

The structure of the LED units 3 out 1 is known and again in detail in 2 shown. The functionalities of the data processing described below and the control of the LEDs 301 to 303 be through the integrated circuit 4 the LED unit 3 realized. In 2 One recognizes an input CKI and an output CKO for the clock signal of the clock line CL. Further, a data input terminal SDI and a data output terminal SDO for the bit stream are provided on the data line DL. The received bit stream of the data line DL and the clock signal of the clock line CL reach the serial data input DI. Subsequently, the bit stream is decoded in the decoder DEC.

With the processing module described below 1 will be in exact chronological order for each of the LEDs 301 to 303 generates a so-called LED frame. The frames of all LEDs of an LED unit 3 be as a package on the data bus 2 transmitted and decoded in the decoder DEC. After decoding, it is checked whether the current packet for the corresponding LED unit is determined, which can be recognized by a code in the frame. If so, the decoded bitstream is applied to respective shift registers SR1 to SR3, the shift register SR1 being the red LED 301 , the shift register SR2 of the green LED 302 and the shift register SR3 of the blue LED 303 assigned. On the individual shift registers thus the corresponding signal for driving the respective LED is given. The signal is a sequence of high / low signals in the LED unit 3 into a PWM signal to supply power to the individual LEDs 301 to 303 is converted. For this purpose, the three PWM generators G1, G2 and G3 are provided, analogous to the shift registers, the generator G1 for the red LED 301 , the generator G2 for the green LED 302 and the generator G3 for the blue LED 303 is provided. The individual PWM generators are connected to an oscillator OS, which receives an oscillator signal at the oscillator input OSCI.

The power supply to the LEDs 301 to 303 takes place via the input VDD and the output VREG, between which there is a rule RE. The input and the output are coupled to line L1. As a rule, a voltage of 5 V is supplied thereto. In contrast, the grounding of the LEDs via the terminal VSS, which is coupled to the line L2.

As already mentioned, the SPI data bus known per se is used to provide the bit stream for the individual LEDs 1 with reference number 2 is designated. It is essential to the invention now that the bit stream on the line DL by means of a processing module 1 is generated on a motor vehicle data bus 6 which is a LIN bus in the embodiment described herein. The processing module 1 includes a LIN transceiver 101 , the corresponding digital signals for driving the LED units 3 from the LIN bus 6 as well as a microprocessor 102 which converts the tapped signals into corresponding data signals on the data line DL. The on the LIN bus 6 In this case, transmitted signals comprise signals which are intended for the lighting device and define a light pattern to be set for the lighting device. These signals in turn come from a control unit of the motor vehicle, which determines the light pattern to be generated based on an input of the driver, for example, and outputs it as a corresponding signal to the LIN bus. About the processing module 1 it detects whether the light pattern corresponds to the current signal on the LIN bus 6 is provided for the lighting device. If so, this signal is sent by the microprocessor 102 in a corresponding signal for the SPI data bus 2 implemented.

In a particularly preferred embodiment of the invention are by the microprocessor 102 the signals for the SPI bus 2 generated by software SPI. Software SPI is well known in the art and is a program library, with any free pins of the microprocessor to signal output to the SPI bus 2 can be used. Alternatively, however, hardware SPI can also be used. There are special SPI pins for signal output to the SPI bus 2 intended. The use of software SPI has the advantage of being in the internal data bus 2 several lines DL and CL for controlling a larger number of LED units 3 can be provided.

The variant of the invention described above has a number of advantages. In particular, by the conversion of a signal on a LIN bus into an SPI signal, the driving of a very large number of LED units can be achieved. In addition, by using the software SPI method, any pins in a corresponding processing module can be used to generate signals for the SPI bus. In particular, if necessary, only a single processing module may be used to drive all of the LED units provided in a particular area of the motor vehicle (e.g., door or seat). When using the lighting device according to the invention, furthermore, the existing LIN architecture can be retained in a motor vehicle. Likewise, known per se LED units can be used. It is only necessary to implement a suitable conversion of the LIN signals on the LIN bus into signals of an SPI bus.

LIST OF REFERENCE NUMBERS

1

processing module

101

LIN Transceivers

102

microprocessor

2

internal data bus

3

LED units

301, 302, 303

LEDs

4

integrated circuit

5

power supply

6

Motor vehicle data bus

CL

Line for clock signal

DL

data line

L1, L2

power lines

RE

voltage regulators

DI

serial data input

DEC

decoder

SR1, SR2, SR3

shift register

G1, G2, G3

PWM generators

OS

oscillator

CO

current output

VDD, VREG, VSS

voltage connections

CKI, CKO

Connections for clock signal

SDI, SDO

data connections

OSCI

Connection for oscillator signal

Claims (14)

Lighting device for a motor vehicle, comprising one or more processing modules ( 1 ) as well as an internal data bus ( 2 ) and a plurality of LED units ( 3 ); where the internal data bus ( 2 ) is an SPI bus or a differential data bus, wherein a differential data bus encodes digital data about a voltage difference between two lines; wherein a respective processing module ( 1 ) several LED units ( 3 ) from the plurality of LED units ( 3 ) and the respective processing module ( 1 ) with the associated LED units ( 3 ) via the internal data bus ( 2 ) is coupled; the associated LED units ( 3 ) one or more LEDs ( 301 . 302 . 303 ) and an integrated circuit ( 4 ) and to a power supply ( 5 ) for the LED or LEDs ( 301 . 302 . 303 ) are connected; the respective processing module ( 1 ) for coupling to a motor vehicle data bus ( 6 ) is arranged to generate first digital control commands for operating the lighting device from the motor vehicle data bus ( 6 ) and as second digital control commands on the internal data bus ( 2 to give); the associated LED units ( 3 ) are adapted to their LEDs ( 3 ) Power from the power supply ( 5 ) based on the second digital control commands on the internal data bus ( 2 ) by means of integrated circuits ( 4 ). Lighting device according to claim 1, characterized in that the processing module or modules ( 1 ) for coupling to a motor vehicle data bus ( 6 ) are arranged in the form of a LIN bus. Lighting device according to claim 1 or 2, characterized in that the internal data bus ( 2 ) is an SPI bus and the processing module or modules ( 1 ) are configured such that the first digital control signals are given to the SPI bus by means of software SPI and / or hardware SPI. Lighting device according to one of the preceding claims, characterized in that the internal data bus ( 2 ) is a differential data bus in the form of an APIX bus. Lighting device according to one of the preceding claims, characterized in that a respective processing module ( 1 ) at least part of the processing modules ( 1 ) with the internal data bus ( 2 ), that for several different subsets of the respective processing module ( 1 ) associated LED units ( 3 ) one or more, only the respective subset associated data lines (DL) of the internal data bus ( 2 ) with the respective processing module ( 1 ) are connected to transmit the second digital control commands via this. Lighting device according to one of the preceding claims, characterized in that the lighting device is a single processing module ( 1 ) for all LED units ( 3 ) of the plurality of LED units ( 3 ). Lighting device according to one of the preceding claims, characterized in that one or more of the LED units ( 3 ) from the plurality of LED units ( 3 ) Are RGB LED units with a red, green and blue LED and / or RGBW LED units with a red, green, blue and white LED. Lighting device according to one of the preceding claims, characterized in that one or more of the LED units of the plurality of LED units are white light LED units with a white LED. Lighting device according to one of the preceding claims, characterized in that one or more of the LED units ( 3 ) from the plurality of LED units ( 3 ) Are single color LED units with a single color LED. Lighting device according to one of the preceding claims, characterized in that one or more of the LED units ( 3 ) from the plurality of LED units ( 3 ) are each configured such that the integrated circuit ( 4 ) and the one or more LEDs ( 301 . 302 . 303 ) of the respective LED unit ( 3 ) are integrated in a common housing. Lighting device according to one of the preceding claims, characterized in that one or more of the LED units ( 3 ) from the plurality of LED units ( 3 ) are respectively adapted to the one or more LEDs ( 301 . 302 . 303 ) of the respective LED unit ( 3 ) Power from the power supply ( 5 ) via PWM modulation. Lighting device according to one of the preceding claims, characterized in that one or more of the LED units ( 3 ) from the plurality of LED units ( 3 ) are respectively adapted to the one or more LEDs ( 301 . 302 . 303 ) of the respective LED unit ( 3 ) Power from the power supply ( 5 ) via the setting to supply variable current levels. Lighting device according to one of the preceding claims, characterized in that the lighting device is an interior lighting in the motor vehicle or an exterior lighting on the outside of the motor vehicle.  Motor vehicle comprising one or more lighting devices according to one of the preceding claims.

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