KR102543456B1 - LED driving apparatus for vehicle lamp - Google Patents

Abstract

The present invention relates to a vehicle lamp LED driving device, which includes a main LDM (LED Drive Module) and one or more sub LDMs connected in series with the main LDM, and NTC (Negative Temperature Coefficient Efficiency of LEDs driven by each sub LDM). ) Resistor and bin (BIN) resistor are respectively connected to the NTC signal bus and the bin signal bus, and the main LDM performs chip selection (CS) through one of a plurality of chip selection signal wires according to the vehicle signal. A signal is output to select one sub-LDM, and temperature and bin information are received from the NTC resistance and bin resistance of the LED driven by the selected sub-LDM through the NTC signal bus and the bin signal bus to drive the corresponding LED. The number of signal lines or connector pins required to receive temperature and bin information can be reduced by generating a control signal for controlling voltage and current.

Description

Vehicle lamp LED driving device {LED driving apparatus for vehicle lamp}

The present invention relates to a vehicle lamp LED driving device, and more particularly, in an LDM composed of one or more sub LDMs connected in series with a main LDM, by using a chip select signal to control each LED through a signal bus (BUS). It relates to a vehicle lamp LED driving device receiving NTC and bin information.

In general, vehicles are provided with various vehicle lamp devices having a lighting function for easily identifying objects located around the vehicle during night driving and a signal function for informing other vehicles or road users of the driving state of the vehicle. For example, among various vehicle lamps, headlights and fog lights are intended for lighting functions, and direction indicators, brake lights, and sidelights are for signaling functions.

Among them, vehicle lamps for the purpose of lighting function generally use projection lamps, and these projection lamps are unitized lamps themselves. In addition, in order to increase the utilization of space, a lamp serving as a sidelight lamp is added and used in the housing of the projection lamp. In general, when a sidelight lamp is added and used in the housing of a projection lamp, an incandescent light bulb serving as a sidelight lamp is embedded and used. Therefore, the degree of freedom in the design of the lamp is limited, and there is a problem in that the incandescent bulb must be frequently replaced due to the limited lifetime of the incandescent bulb. In addition, there is a problem in that the reliability of the incandescent bulb cannot be guaranteed because the internal temperature is increased due to the heat generated from the incandescent bulb used as a sidelight.

Therefore, in recent years, LEDs have been used instead of incandescent bulbs as sidelights to solve various problems caused by using incandescent bulbs. For example, by using an LED instead of an incandescent light bulb as a sidelight lamp, the design freedom of the lamp can be increased because the space occupied by the LED is small, and the LED can be used semi-permanently due to its long lifespan.

In applying the LED to the vehicle lamp, an LDM (LED Drive Module) for driving the LED was used, and one LDM was used for each function (High, Low, Turn, DRL, Fog, etc.). However, when a separate LDM is manufactured differently according to options, such as selecting only some or all of various functions, there is a problem in that the manufacturing process becomes complicated and the LDM is increased according to a specific option.

Accordingly, there is a need to control a plurality of sub LDMs with a single main LDM. Conventionally, if the function is increased, each LDM with a DC/DC converter must be made to control each input and output. The LDM can drive the LED by converting current with a DC/DC converter. However, when controlling multiple Sub LDMs with a single Main LDM, there is a problem in that the number of wires between the Main LDM and Sub LDM increases as the number of lamps using LEDs increases. need.

Korean Patent Publication No. 10-2011-0033663

A problem to be solved by the present invention is a vehicle lamp LED that receives NTC and bin information of each LED through a signal bus using a chip select signal in an LDM composed of one or more sub LDMs connected in series with a main LDM. to provide a driving device.

The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above problems, a vehicle lamp LED driving device according to an embodiment of the present invention includes a main LDM (LED Drive Module) and one or more sub-LDMs connected in series with the main LDM, each sub-LDM NTC (Negative Temperature Coefficient) resistance and BIN resistance of the driven LED are connected to the NTC signal bus and the empty signal bus, respectively, and the main LDM selects one chip among a plurality of chip selection signal wires according to the vehicle signal. A chip select (CS) signal is output through a signal wire to select one sub-LDM, and temperature and bin information are transmitted from the NTC resistance of the LED driven by the selected sub-LDM and bin resistance to the NTC signal bus and the bin signal. It is characterized in that it generates a control signal for controlling the voltage and current for driving the corresponding LED by receiving it through the bus.

In addition, the main LDM and the sub LDM transmit and receive data through SPI communication, and the chip select signal may be a chip select signal used in the SPI communication. The NTC signal bus and the empty signal bus are connected to the main LDM. It may be a bus (BUS) extending from LDM to all sub-LDMs.

In addition, the sub-LDM includes a switching element that connects between the chip select signal line and the NTC resistance and empty resistance of the LED, and the switching element, when a signal is applied to the chip select signal line, the NTC resistance and the The NTC voltage and the vacant voltage may be input to the main LDM through the NTC signal bus and the vacant signal bus, and the switching element may be a bipolar transistor (BJT) Alternatively, a field effect transistor (FET) may be included.

The sub-LDM may further include a signal inverting unit connecting the chip select signal line and the switching element and inverting a signal, wherein the signal inverting unit outputs the chip select signal at a low level. , a chip select signal may be inverted to a high level to turn on the switching element, and the switching element may be an NPN type bipolar transistor or an N-channel MOSFET.

In addition, the main LDM and the sub LDM are formed in the form of modules that can be assembled, and a plurality of sub LDMs can be assembled and connected in series to the main LDM.

In addition, the LED may include one or more LED light sources.

Other specific details of the invention are included in the detailed description and drawings.

According to embodiments of the present invention, at least the following effects are provided.

According to the present invention, in an LDM composed of one or more sub-LDMs connected in series with a main LDM, the temperature and bin information of each LED is received through a signal bus using a chip select signal, which is required to receive the temperature and bin information. The number of signal lines or connector pins can be reduced. Through this, cost reduction and miniaturization can be achieved.

Effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a block diagram of a vehicle lamp LED driving device according to an embodiment of the present invention.
2 and 3 are block diagrams of a vehicle lamp LED driving device according to another embodiment of the present invention.
Figure 4 shows a form in which the vehicle lamp LED driving device according to an embodiment of the present invention is assembled.
5 shows a configuration of a vehicle lamp LED driving device to which SPI communication is applied, and FIG. 6 illustrates a configuration of a vehicle lamp LED driving device according to an embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

Terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, "comprises" and/or "comprising" does not exclude the presence or addition of one or more other elements other than the recited elements.

1 is a block diagram of a vehicle lamp LED driving device according to an embodiment of the present invention.

The characteristics of LEDs, such as chromaticity and luminance, change during the manufacturing process. Grouping according to the characteristic range of these LEDs is called a bin (BIN). The normal voltage or current level required for the LED may vary according to the empty code according to the characteristics of the LED. Since the LED is sensitive to voltage and current, it is necessary to provide a regular voltage or current suitable for the characteristics of the LED. When a plurality of LEDs are used in one vehicle, since it is difficult to use LEDs all having the same empty code, it is necessary to check the empty code information of each LED and provide a corresponding regular voltage and current to the corresponding LED.

In addition, the LED is sensitive to current, and when the temperature increases due to an increase in the operating time of the LED, the current flowing through the LED may increase. Temperature coefficient) resistance should be included in the LED, and suitable regular voltage and current should be provided to the LED according to the temperature information according to the NTC. That is, bin information and temperature information must be known in order to provide a normal voltage and current suitable for the LED to the corresponding LED.

In order to read empty information and temperature information from each LED, a vehicle lamp LED driving device 100 according to an embodiment of the present invention is composed of a main LDM (LED Drive Module, 110) and a sub LDM 120, (200) may be further included.

The main LDM (110) outputs a signal to the sub LDM (120), reads the temperature and bin information according to the NTC resistance (210) and empty resistance (220) of the LED (200), and voltage and current suitable for driving the corresponding LED. It is possible to generate a control signal for controlling. Here, a control signal suitable for driving the LED 200 may be a Puse Width Modulation (PWM) signal. The PWM signal is a signal having a predetermined pulse width, and the pulse width may vary depending on the characteristics of the corresponding LED.

The main LDM 110 may include a control unit 111. The control unit 111 controls a signal output from the main LDM 110 to the sub LDM 120, and according to the NTC resistance 210 and empty resistance 220 of the LED 200, the voltage and current suitable for driving the corresponding LED It is possible to generate a control signal for controlling. The generated control signal is transmitted to the sub LDM (120).

The sub LDM 120 is connected in series with the main LDM 110. A driving LED 200 is connected to the sub LDM 120 . In the sub-LDM 120 , a plurality of sub-LDMs (a first sub-LDM to an n-th sub-LDM) may be connected in series according to the type and number of LEDs required for a vehicle, as shown in FIG. 2 . Here, the LED 200 may be used as a head lamp, a fog lamp, a turn signal lamp, a tail lamp, a brake lamp, a side marker, and the like. Each sub-LDM (first sub-LDM, second sub-LDM to n-th sub-LDM) is connected to a driving LED (first LED, second LED to n-th LED), respectively. The sub LDM 120 may include an LED driver for driving the LED using a control signal for controlling voltage and current to drive the corresponding LED received from the main LDM 110 .

The LED 200 includes an NTC resistor 210 and a BIN resistor 220 reflecting the characteristics of the LED itself. The NTC resistor 210 and the empty resistor 220 are formed with specifications according to the characteristics of the LED. The NTC resistor 210 and the empty resistor 220 of each LED are connected to the NTC signal bus 140 and the empty signal bus 130, respectively. Each of the NTC signal bus 140 and the empty signal bus 130 is formed of one wire and is a bus (BUS) extending from the main LDM 110 to all sub LDMs 120. A bus (BUS) is a common information transmission path in a manner of commonly connecting each device by making a set of signal buses between several devices for transmitting and receiving information between devices. A normal balanced cable can be used for the bus, and a necessary number of bus drivers that transmit information and bus receivers that receive information can be connected in parallel.

The main LDM 110 may select one sub LDM by outputting a chip select (CS) signal through one of a plurality of chip select signal wires according to a vehicle signal. The main LDM 110 receives a vehicle signal including information about which lamp function to select for which sub LDM or its lamp setting, and in order to select the corresponding sub LDM according to the vehicle signal, a plurality of chip selection signal wires are used. A chip selection signal is output through the corresponding chip selection signal wire. The vehicle signal includes a lamp-related signal according to a driver's operation or a lamp-related signal generated according to an external or internal environment of the vehicle, such as an oncoming vehicle.

The main LDM 110 outputs a chip selection signal to select a sub LDM driving an LED to receive temperature and empty information. When a chip selection signal for selecting one sub-LDM is output, temperature and bin information are transmitted from the NTC resistance of the LED driven by the selected sub-LDM and bin resistance to the NTC signal bus 140 and the bin signal bus 130. Through this, the main LDM (110) receives. Temperature information is received through the voltage across the NTC resistance, and bin information is received through the voltage across the empty resistance. When the chip select signal is not output from the main LDM 110, current does not flow through the NTC signal bus 140 and the empty signal bus 130. Even if voltage is applied to the NTC signal bus 140 and the empty signal bus 130, no current flows through the NTC signal bus 140 and the empty signal bus 130 because no path is formed unless the chip select signal is output. . A voltage of 5 V may be applied to each of the NTC signal bus 140 and the empty signal bus 130.

The main LDM 110 and the sub LDM 120 transmit and receive data through SPI (Serial Peripheral Interface) communication, and the chip selection signal output by the main LDM 110 to select one sub LDM is used in the SPI communication. may be a chip select signal to be SPI communication transmits and receives data by synchronizing a signal to a clock to output or receive data, and selecting a chip to output or receive data. To perform SPI communication, a chip selection signal for selecting a chip is required. Therefore, a sub-LDM is selected using the chip selection signal necessary for SPI communication, and the NTC resistance and blank resistance of the LED driven by the sub-LDM are selected. Receives temperature and bin information from A separate signal different from the chip select signal of SPI communication may be used as the chip select signal. The chip select signal may be transmitted and received through a plurality of chip select signal wires connecting the main LDM 110 and the sub LDM 120 . Chip select signal wires may be individually connected between the main LDM 110 and the sub LDM, and the number of chip select signal wires may be the same as the number of sub LDMs serially connected to the main LDM 120.

The sub LDM 120 includes a switching element 121 connecting between the chip selection signal line 150 and the NTC resistor 210 and the empty resistor 220 of the LED, and the switching element 121 is the chip selection signal line When a signal is applied to 150, it is turned on so that current flows through the NTC resistor 210 and the empty resistor 220, so that the NTC voltage and the empty voltage are connected to the NTC signal bus 140 and the empty signal bus 130. ) to be input to the main LDM 110. Since the NTC resistor 210 and empty resistor 220 of the LED are always connected to the bus, NTC information and blank information are input through the bus only when the chip select signal for selecting the sub-LDM driving the corresponding LED is output. To do this, a switching element 121 may be used. The switching element 121 is turned on only when the chip select signal for selecting the corresponding sub-LDM is output, and current flows through the NTC resistor 210 and the empty resistor 220, and the NTC resistor 210 and the empty resistor When current flows through 220, the NTC voltage and the empty voltage are input to the main LDM 110 through the NTC signal bus 140 and the empty signal bus 130.

The switching element 121 may include a bipolar transistor (BJT) or a field effect transistor (FET). The switching element 121 may be implemented as a bipolar transistor or a field effect transistor capable of performing a switching operation, and may further include elements implementing resistance or power required to drive the bipolar transistor or field effect transistor.

As shown in FIG. 3 , the sub LDM 120 may further include a signal inverting unit 122 connecting the chip select signal line 150 and the switching element 121 and inverting a signal. In SPI communication, the chip select signal is output at a low level according to the communication protocol. In order to turn on the switching element using a low-level signal, the switching element may be implemented as a PNP type bipolar transistor or a P-channel MOSFET. When a switching element is implemented with a PNP type bipolar transistor or a P-channel MOSFET, a circuit capable of applying a separate voltage may be further included because a separate voltage needs to be applied. However, when the switching element 121 is implemented with an NPN type bipolar transistor or an N-channel MOSFET, it can be directly connected to the ground (ground, GND), so a circuit or resistor for applying a separate voltage is unnecessary, so the circuit can be implemented simply. can However, when the switching element 121 is implemented with an NPN type bipolar transistor or an N-channel MOSFET, a signal inverting unit 122 inverting the chip select signal to a high level may be further included since the chip select signal is a low level in SPI communication. When the chip select signal 150 is output at a low level, the signal inverting unit 122 may turn on the switching device 121 by inverting the chip select signal to a high level. When a separate high-level signal is used as the chip select signal instead of the SPI communication chip select signal, the switching device 121 may be implemented as an NPN type bipolar transistor or an N-channel MOSFET without a signal inverting unit. In this case, on the contrary, when the switching element is implemented with a PNP type bipolar transistor or a P-channel MOSFET, a circuit for inverting the chip select signal from high to low is required.

The main LDM 110 may generate a control signal for driving a corresponding LED according to the input temperature and bin information and output the generated control signal to the corresponding sub LDM. The main LDM (110) receiving the temperature and empty information of the corresponding LED through the output of the chip selection signal needs to drive the corresponding LED or receives a signal to drive the corresponding LED according to the temperature and empty information of the corresponding LED. A control signal for controlling voltage and current for driving the corresponding LED may be generated and output to the corresponding sub-LDM. At this time, the output signal is output to the corresponding sub-LDM through SPI communication. At this time, a clock (CLK) signal, a serial data output (SDO) signal, or a serial data input (SDI) signal may be used. The clock signal, SDO signal, SDI signal, and chip select signal are applied to the LED driver of each sub-LDM. When the LED driving unit (driver) receives a control signal through SPI communication, it drives the LED with a corresponding regular current or voltage.

When a plurality of sub LDMs are connected in series to one main LDM, the main LDM and the sub LDMs are formed in the form of modules that can be assembled, and the plurality of sub LDMs can be assembled and connected in series to the main LDM. As shown in FIG. 4, each LDM module may be manufactured, and each LDM module may be assembled and connected to manufacture a single LDM driving device. Each LDM is connected via a connector, which can be configured to the number of signal lines required. Each LDM can be bolted or hooked for assembly connection. The number and order of connection of each sub-LDM may vary. Even after being connected once, if necessary, the order can be changed or replaced.

5 shows a configuration of a vehicle lamp LED driving device to which SPI communication is applied, and FIG. 6 illustrates a configuration of a vehicle lamp LED driving device according to an embodiment of the present invention.

In a vehicle lamp LED driving device in which a plurality of sub LDMs are connected in series to one main LDM, types of signal lines connecting the main LDM and sub LDM include clock (CLK), SDO, SDI, CS, BIN, and NTC. there is. In order to individually read the temperature (NTC) information and bin (BIN) information of each LED, as shown in FIG. 5, the same number of signal lines (BIN1 to BINn, and NTC1 to NTCn) are required.

However, the vehicle lamp LED driving device according to an embodiment of the present invention reduces the signal line connecting the main LDM and the sub LDM necessary for reading temperature and empty information to two as shown in FIG. 6 by using a chip select signal and a signal bus. can When the chip select signal (one of CS1, CS2 to CSn) is output from the main LDM, the switching element (inverting circuit and NPN type BJT ), the current flows through the NTC resistor and the bin resistor, and the resulting voltage across the NTC resistor and the voltage across the bin resistor are input to the main LDM through the NTC BUS and BIN BUS. That is, the signal lines (BIN1 to BINn and NTC1 to NTCn) of FIG. 5 can be reduced to two signal lines of NTC BUS and BIN BUS.

Those skilled in the art to which the present invention pertains will understand that the present invention can be embodied in other specific forms without changing its technical spirit or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention. do.

100: vehicle lamp LED driving device
110: main LDM
111: control unit
120: sub LDM
121: switching element
122: signal inversion unit
130: BIN signal bus
140: NTC signal bus
150: chip select signal line
200: LED
210: NTC resistance
220: empty resistance

Claims (10)

Main LDM (LED Drive Module); and
Including a plurality of sub LDMs connected in series with the main LDM,
NTC (Negative Temperature Coefficient) resistance and bin (BIN) resistance of the LED driven by each of the plurality of sub-LDMs are connected to the main LDM through an NTC signal bus and a bin signal bus,
The main LDM,
Selecting one sub LDM from among the plurality of sub LDMs according to a vehicle signal;
outputting a chip select (CS) signal through a chip select signal line corresponding to the selected sub-LDM among a plurality of chip select signal lines;
receiving temperature and bin information that can be confirmed through an NTC resistance and bin resistance of the target LED from a target LED receiving the chip selection signal through the NTC signal bus and the bin signal bus;
Vehicle lamp LED driving device, characterized in that for generating a control signal for controlling the voltage and current for driving the target LED based on the temperature and empty information. According to claim 1,
The main LDM and the plurality of sub LDMs transmit and receive data through SPI communication,
The chip select signal,
Vehicle lamp LED driving device, characterized in that the chip selection signal used in the SPI communication. According to claim 1,
The NTC signal bus and the empty signal bus,
A vehicle lamp LED driving device, characterized in that a bus (BUS) extending from the main LDM to the plurality of sub LDMs. According to claim 1,
Each of the plurality of sub LDMs,
A switching element connecting between the chip selection signal line and the corresponding LED's NTC resistance and empty resistance,
The switching element,
When a signal is applied to the chip select signal line, it is turned on so that current flows through the NTC resistor and the vacant resistor, so that the NTC voltage applied to the NTC resistor and the vacant voltage applied to the vacant resistor are the NTC signal bus and a vehicle lamp LED driving device characterized in that input to the main LDM through the empty signal bus. According to claim 4,
The switching device is a vehicle lamp LED driving device, characterized in that it comprises a bipolar transistor (BJT) or a field effect transistor (FET). According to claim 4,
Each of the plurality of sub LDMs,
The vehicle lamp LED driving device further comprises a signal inverting unit connecting the chip selection signal line and the switching element and inverting the signal. According to claim 6,
The signal inversion unit,
When the chip select signal is output at a low level, the chip select signal is inverted to a high level to turn on the switching element. According to claim 4,
The switching element,
Vehicle lamp LED driving device, characterized in that NPN type bipolar transistor or N-channel MOSFET. According to claim 1,
The main LDM and the plurality of sub LDMs are formed in the form of modules that can be assembled,
A vehicle lamp LED driving device, characterized in that the plurality of sub LDMs are assembled and connected in series to the main LDM. According to claim 1,
The LED driven by each of the plurality of sub LDMs,
A vehicle lamp LED driving device comprising at least one LED light source.

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