KR102581389B1 - Apparatus for driving light emitting diode - Google Patents

Abstract

The present invention relates to an LED driving device.
An LED driving device according to an embodiment of the present invention includes one or more LED arrays and a comparison unit that compares signals and reference signals input from each LED array, the same as the number of LED arrays, and outputs a status signal of each LED array. , a constant current output unit that is equal to the number of LED arrays and whose operation is determined according to the operation presence or absence signal and outputs a constant current that operates each LED array; and a constant current output unit that is equal to the number of LED arrays and corresponds to the status signal output from the comparison unit. It includes a control unit that outputs an operation presence signal, and in response to the first status signal among the status signals output from the comparison unit, the control unit outputs an operation presence signal for operating the constant current output unit, and a second status signal among the status signals output from the comparison unit. In response to the status signal, the control unit may output a no-operation signal that stops the entire operation of the constant current output unit.

Description

LED driving device{APPARATUS FOR DRIVING LIGHT EMITTING DIODE}

The present invention relates to an LED driving device.

In recent years, thanks to advancements in semiconductor technology, the efficiency of LEDs (light emitting diodes) has improved significantly. In addition, LEDs have the advantage of being not only economical but also environmentally friendly due to their significantly longer lifespan and lower energy consumption compared to existing lighting devices such as incandescent bulbs or fluorescent lamps. Due to these advantages, LED is rapidly spreading not only in general household lighting, but also in automotive lighting such as headlights, side lights, tail lights, and interior lights.

The LED driving device according to the prior art includes a DC voltage regulator, a plurality of LED strings, and a plurality of constant current and feedback control units. In particular, the DC voltage regulator includes a boosting circuit, which is causing an increase in cost.

The above-mentioned background technology is technical information that the inventor possessed for deriving the present invention or acquired in the process of deriving the present invention, and cannot necessarily be said to be known art disclosed to the general public before filing the application for the present invention.

Domestic Patent Publication No. 10-1247506

It was designed to solve the above-mentioned problems and/or limitations, and its purpose is to provide a low-cost linear LED driving device that eliminates the boosting circuit in the conventional LED driving device and disables all LEDs when one LED array fails. there is.

An LED driving device according to an embodiment of the present invention includes one or more LED arrays; A comparison unit that is equal to the number of LED arrays and outputs a status signal of each LED array by comparing signals and reference signals input from each of the LED arrays; A constant current output unit that is equal to the number of LED arrays and whose operation is determined according to an operation presence or absence signal to output a constant current to operate each of the LED arrays; And a control unit that is equal to the number of LED arrays and outputs the operation presence/absence signal in response to the status signal output from the comparison unit, and corresponding to a first status signal among the status signals output from the comparison unit. Thus, the control unit outputs an operation active signal to operate the constant current output unit, and in response to the second status signal among the status signals output from the comparison unit, the control unit outputs an operation no signal to stop the entire operation of the constant current output unit. Can be printed.

The LED driving device may further include a switching unit that is equal to the number of LED arrays and is switched on when the constant current output unit operates and switched off when the constant current output unit stops operating.

The constant current output unit may include an operational amplifier, the first input terminal of which is connected to a reference voltage, the second input terminal of which is connected to the output terminal of the constant current output unit, and the control terminal of which is connected to the output terminal of the control unit.

The control unit includes a first resistor, the first terminal of which is connected to a power supply voltage, and the second terminal of which is connected to the output terminal of the comparison unit; a second resistor whose first terminal is connected to the power voltage; a first switch whose first terminal is connected to the output terminal of the comparator, whose second terminal is connected to ground, and whose third terminal is connected to the second terminal of the second resistor; a third resistor whose first terminal is connected to the output terminal of the comparator and whose second terminal is connected to the first terminal of the first switch; a fourth resistor whose first terminal is connected to the second terminal of a second resistor; and a second switch, the first terminal of which is connected to the second terminal of the fourth resistor, the second terminal of which is connected to the control terminal of the operational amplifier, and the third terminal of which is connected to the power supply voltage.

The first switch and the second switch may have opposite polarities.

In addition to this, other methods for implementing the present invention, other systems, and computer programs for executing the methods may be further provided.

Other aspects, features and advantages in addition to those described above will become apparent from the following drawings, claims and detailed description of the invention.

According to embodiments, it is possible to implement a low-cost linear LED driving device that eliminates the boosting circuit in the conventional LED driving device and extinguishes all LEDs when one LED array fails.

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

1 is a block diagram of an LED driving device according to an embodiment of the present invention.
FIG. 2 is a partial circuit diagram of an LED driving module in the LED driving device of FIG. 1.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments presented below, but may be implemented in various different forms, and should be understood to include all conversions, equivalents, and substitutes included in the spirit and technical scope of the present invention. . The embodiments presented below are provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof. Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by these terms. The above terms are used only for the purpose of distinguishing one component from another.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, identical or corresponding components are assigned the same drawing numbers and duplicate descriptions thereof are omitted. I decided to do it.

FIG. 1 is a block diagram of an LED driving device according to an embodiment of the present invention, and FIG. 2 is a partial circuit diagram of an LED driving module in the LED driving device of FIG. 1. Referring to Figures 1 and 2, the LED driving device includes a smart junction box (SJP) 100, an LED driving module (LDM) (hereinafter referred to as LDM) ( 200), an LED array module (LAM: LED array module, hereinafter referred to as LAM) 300, and a connector 400.

SJP (100) can supply battery power to various electrical devices that consume electricity in the vehicle, such as lamps, body electronic components, multimedia devices, and motor drives. In this embodiment, the lamps include exterior lamps, head lamps, turn lamps, fog lamps, daytime running lamps (DRL), position lamps (PSTN), and stop lamps. It may include a stop lamp, a break lamp, etc.

The LDM (200) can control the power supplied from the SJP (100) to maintain a constant current in the LAM (300). Here, the LDM (200) can be designed in various forms depending on the quantity (or number) of LEDs configured in the LAM (300). The LAM 300 includes various lamps used in vehicles, and may include one or more LED arrays, for example, the first LED array 300_1 to the N-th LED array 300_N. The first LED array 300_1 to the Nth LED array 300_N may be turned on or off by controlling current supply from the LDM 200. For convenience of explanation, the first LED array 300_1 to the N-th LED array 300_N will be described as the LAM 300 including position lights (PSTN) and daytime running lights (DRL).

The connector 400 can electrically connect the LDM (200) and the LAM (300).

Hereinafter, the operation of the LDM 200 will be described in detail. The LDM 200 includes a first ESD protection unit 211, a second ESD protection unit 212, a first reverse voltage prevention unit 221, a second reverse voltage prevention unit 222, an input noise filter 231, Includes an output noise filter 232, a regulator 241, a timer 242, a reset unit 243, a comparison unit 250, a constant current output unit 260, a switching unit 270, and a constant current output control unit 280. can do. In this embodiment, the comparison unit 250, the constant current output unit 260, and the switching unit 270 may be provided in the same number as the number of the first to N-th LED arrays 300_1 to 300_N.

Since a large current difference is formed between the input terminal and the output terminal of the LDM (200), the first ESD (electric static discharge) protection unit 211 and the second ESD protection unit 212 discharge static electricity, and the first reverse voltage prevention unit 221 and the second reverse voltage prevention unit 222 may prevent reverse voltage of the voltage input from the SJP 100 for driving control of the position lights (PSTN) and daytime running lights (DRL). The input noise filter 231 removes noise from the voltage input from the SJP 100 for driving control of the position lights (PSTN) and daytime running lights (DRL), and the output noise filter 232 removes noise from the voltage input from the LDM (200). Noise generated internally can be removed. Accordingly, the lamp driving power output from the SJP (100) can be input to the first LED array (300_1) to the N-th LED array (300_N) through electrostatic discharge, reverse voltage prevention, and noise removal processes in the LDM (200). .

The regulator 241 provides a voltage for controlling the operation of position lights (PSTN) or daytime running lights (DRL) in which the reverse voltage output from the first reverse voltage prevention unit 221 and the second reverse voltage prevention unit 222 is prevented. A reference voltage (for example, 5V) that can be used inside the LDM (200) can be generated and output.

The timer 242 may receive the reference voltage output from the regulator 241 and output a pulse width modulation (PWM) signal as a switching signal. Turning on and off the first LED array (300_1) to the N-th LED array (300_N) can be controlled using the PWM signal output from the timer 242, and this PWM signal is sent to the output terminal of the constant current output unit 260. and may be connected to the input terminal of the switching unit 270.

The basic operation of the LDM (200) is performed by controlling the position light (PSTN). When the voltage for driving the daytime running light is input, the reset unit 243 stops the timer 242 from operating and outputs DC current. You can.

The comparator 250 compares the signal and the reference signal input from each of the first LED array (300_1) to the N-th LED array (300_N) to determine the state of each of the first LED array (300_1) to the N-th LED array (300_N). A signal can be output. Here, the first terminal (+ terminal) of the first LED array (300_1) to the N-th LED array (300_N) is connected to the output noise filter 232, and the first LED array (300_1) to the N-th LED array (300_N) is connected to the output noise filter 232. ) may be connected to the first input terminal of the corresponding comparison unit 250.

Referring to FIG. 2 , the comparison unit 250 may include a first comparison unit 250_1 to an N-th comparison unit 250_N. The first input terminals of the first to N-th comparison units 250_N may be connected to the second terminals of the corresponding first to N-th LED arrays 300_N, respectively, and the first The second input terminal of the comparison unit 250_1 to the Nth comparison unit 250_N may be connected to a reference voltage (V_Ref), and the control terminal of the first comparison unit 250_1 to the Nth comparison unit 250_N may be connected to a regulator ( 241) can be connected to the output terminal. A status signal can be output to the output terminal (COMP_OUT) of the first to N-th comparison units 250_1 to 250_N.

That is, the first comparator (250_1) to the N-th comparator (250_N) receives signals input from the first LED array (300_1) to the N-th LED array (300_N) through the first input terminal and the second input terminal. A status signal can be output by comparing the input reference voltage. Here, the signals of the first LED array (300_1) to the N-th LED array (300_N) input through the first input terminal of the first comparison unit (250_1) to the N-th comparison unit (250_N) are the first LED array (300_1). ) When at least one of the N-th LED arrays 300_N is operating normally, it includes a normal signal output from each of the first LED arrays 300_1 to N-th LED arrays 300_N that are operating normally, or the first When one or more of the LED array (300_1) to the N-th LED array (300_N) is operating abnormally due to a failure or the like, the output from each of the first LED array (300_1) to the N-th LED array (300_N) that is operating abnormally is May contain abnormal signals.

Additionally, the status signal output by the comparator 250 to the output terminal (COMP_OUT) may include a first status signal and a second status signal. The first state signal is normal indicating that the first LED array (300_1) to the Nth LED array (300_N) are operating normally by comparing the signal input to the first input terminal and the reference voltage input through the second input terminal. It may include a status signal (eg, a floating signal). The second state signal is an abnormality indicating that the first LED array (300_1) to the Nth LED array (300_N) are operating abnormally by comparing the signal input to the first input terminal and the reference voltage input through the second input terminal. It may include a status signal (eg, a grounding signal).

Returning to FIG. 1, the constant current output unit 260 may output a constant current that operates the first to Nth LED arrays 300_1 to 300_N by determining the operation depending on the operation presence or absence signal. The constant current output unit 260 compares the reference power (V_Ref, for example, 5V) and the output signal (feedback signal, sens.) of the fed back constant current output unit 260 to display the first LED array 300_1 to the Nth LED. A constant current that operates the array 300_N can be output. Here, the operation status of the constant current output unit 260 may be determined by the operation status signal COM_VCC output from the constant current output control unit 280, which will be described later.

Referring to FIG. 2, the constant current output unit 260 may include a first constant current output unit 260_1 to an Nth constant current output unit 260_N, each of which may be designed as an operational amplifier (OP-AMP). . The first input terminal of the first constant current output unit 260_1 to the Nth constant current output unit 260_N may be connected to the reference voltage (V_Ref), and the first constant current output unit 260_1 to the Nth constant current output unit 260_N may be connected to the reference voltage V_Ref. The second input terminal of may be connected to an output signal (feedback signal, sens.) output from the output terminals of the first constant current output unit 260_1 to the Nth constant current output unit 260_N. The output terminal (COM_VCC) of the constant current output control unit 280 that determines the operation may be connected to the control terminal of the first constant current output unit 260_1 to the Nth constant current output unit 260_N. Since the output terminal (COM_VCC) of the constant current output control unit 280 is commonly connected to the control terminal of the first constant current output unit 260_1 to the Nth constant current output unit 260_N, the output terminal of the constant current output control unit 280 When an operation active signal is output from (COM_VCC), the first constant current output unit 260_1 to the Nth constant current output unit 260_N all operate, and a no operation signal is output from the output terminal (COM_VCC) of the constant current output control unit 280. When this happens, the first constant current output unit 260_1 to the Nth constant current output unit 260_N can all stop operating.

Returning to FIG. 1, the switching unit 270 is switched on when the first constant current output unit 260_1 to the Nth constant current output unit 260_N operates to send a constant current to the first LED array 300_1 to the Nth LED array ( 300_N), and when the operation of the first constant current output unit 260_1 to the Nth constant current output unit 260_N is stopped, the switching is turned off to transmit a constant current to the first LED array 300_1 to the Nth LED array 300_N. Transmission can be stopped.

Referring to FIG. 2, the switching unit 270 may include a first switching unit 270_1 to an N-th switching unit 270_N, and each may be designed as a field effect transistor (FET). The first terminal (base) of the first switching unit (270_1) to the N-th switching unit (270_N) may be connected to the output terminal of the first constant current output unit (260_1) to the N-th constant current output unit (260_N), and the first The second terminal (emitter) of the switching unit 270_1 to the N-th switching unit 270_N may be connected to the first terminal of the sensing resistor Rs, and the first switching unit 270_1 to the N-th switching unit 270_N ) may be connected to the second terminals of the first to Nth LED arrays (300_N). Here, the second terminal of the sensing resistor (Rs) may be connected to ground. In addition, the second input terminal of the first constant current output unit 260_1 to the Nth constant current output unit 260_N is connected to the third terminal of the first switching unit 270_1 to Nth switching unit 270_N and the sensing resistance Rs. It can be connected to the first terminal.

Returning to FIG. 1, the constant current output control unit 280 may generate and output an operation status signal that determines whether the constant current output unit 260 is operating in response to the status signal output from the comparator 250. The constant current output control unit 280 generates and outputs an operation signal that operates the constant current output unit 260 in response to the first state signal output from the comparison unit 250, and the second state signal output from the comparison unit 250. In response to the status signal, a no-operation signal that stops the operation of the constant current output unit 260 may be generated and output. Here, since the control terminal (COMP_VCC) of the constant current output unit 260 is commonly connected to the output of the constant current output control unit 280, the constant current output control unit 280 receives the second state signal output from the comparison unit 250. When received, the entire operation of the constant current output unit 260 can be stopped.

Referring to FIG. 2 , the constant current output control unit 280 may include first resistors R1 to fourth resistors R4, a first switch SW1, and a second switch SW2. In this embodiment, the first switch (SW1) and the second switch (SW2) may have opposite polarities, the first switch (SW1) may include an NPN type FET, and the second switch (SW) may include a PNP type FET. type FET may be included.

The first resistor (R1) has a first terminal connected to the power supply voltage (VCC, for example, 5V), and a second terminal connected to the output terminal (COMP_OUT) of the first to N-th comparison units (250_1) to 250_N. can be connected to The first terminal of the second resistor R2 may be connected to the power supply voltage VCC, and the second terminal may be connected to the third terminal of the second switch SW1. The first terminal of the third resistor R3 may be connected to the output terminal (COMP_OUT) of the first to N-th comparators 250_1 to 250_N and the second terminal of the first resistor R1. The first terminal of the fourth resistor R4 may be connected to the second terminal of the second resistor R2 and the third terminal of the first switch SW1. The first switch (SW1) has a first terminal (base) connected to the second terminal of the third resistor (R3), a second terminal (emitter) connected to ground, and a third terminal (collector) connected to the second terminal. It may be connected to the second terminal of the resistor R2 and the first terminal of the fourth resistor R4. The second switch (SW2) has a first terminal (base) connected to the second terminal of the fourth resistor (R4), a second terminal (emitter) connected to the power supply voltage (VCC), and a third terminal (collector). ) may be connected to the control terminal (COMP_VCC) of the first constant current output unit 260_1 to the Nth constant current output unit 260_N.

When the constant current output control unit 280 receives the first state signal from the output terminal (COMP_OUT) of the first comparator 250_1 to the Nth comparator 250_N, the first switch SW1 is turned off, and the first resistor ( The second switch (SW2) is turned on by the power supply voltage (VCC) divided by the R1), the second resistor (R2), and the fourth resistor (R4), so that the first constant current output unit 260_1 to the Nth constant current output An operation signal is input to the control terminal (COMP_VCC) of the unit 260_N, and the first to Nth switching units 270_1 are switched with the output signals of the first constant current output units 260_1 to the Nth constant current output units 260_N. When the unit 270_N is turned on, the constant current generated by the first constant current output unit 260_1 to the Nth constant current output unit 260_N can be supplied to the first LED array 300_1 to the Nth LED array 300_N.

However, when the constant current output control unit 280 receives the second state signal from the output terminal (COMP_OUT) of the first to N-th comparators 250_1 to 250_N, the first resistor R1 and the third resistor R3 ) The first switch (SW1) is turned on and the second switch (SW2) is turned off with the power supply voltage (VCC) divided by ), and the first constant current output unit 260_1 to the Nth constant current output unit 260_N A non-operational signal is input to the control terminal (COMP_VCC), so that the first constant current output unit 260_1 to the Nth constant current output unit 260_N stops operating, and thereby the first switching unit 270_1 to the Nth switching unit When (270_N) is turned off, the entire first LED array (300_1) to the N-th LED array (300_N) may stop operating.

In this way, the expensive boosting circuit provided in the conventional LED driving device is deleted, and when any one of the first LED array (300_1) to the N-th LED array (300_N) does not operate due to a failure or the like, 1 By stopping the entire operation of the constant current output unit (260_1) to the Nth constant current output unit (260_N), and stopping (turning off) the entire operation of the first LED array (300_1) to the Nth LED array (300_N), low-cost linear It becomes possible to implement an LED driving device.

In the specification (particularly in the claims) of the present invention, the use of the term “above” and similar referential terms may refer to both the singular and the plural. In addition, when a range is described in the present invention, the invention includes the application of individual values within the range (unless there is a statement to the contrary), and each individual value constituting the range is described in the detailed description of the invention. It's the same.

Unless there is an explicit order or statement to the contrary regarding the steps constituting the method according to the invention, the steps may be performed in any suitable order. The present invention is not necessarily limited by the order of description of the above steps. The use of any examples or illustrative terms (e.g., etc.) in the present invention is merely to describe the present invention in detail, and unless limited by the claims, the scope of the present invention is limited by the examples or illustrative terms. It doesn't work. Additionally, those skilled in the art will recognize that various modifications, combinations and changes may be made depending on design conditions and factors within the scope of the appended claims or their equivalents.

Therefore, the spirit of the present invention should not be limited to the above-described embodiments, and the scope of the patent claims described below as well as all scopes equivalent to or equivalently changed from the scope of the claims are within the scope of the spirit of the present invention. It will be said to belong to

100: Smart Junction Box (SJB)
200: LED array driving module (LDM)
300: LED array module (LAM)
400: connector

Claims (5)

one or more LED arrays;
A comparison unit that is equal to the number of LED arrays and outputs a status signal of each LED array by comparing signals and reference signals input from each of the LED arrays;
A constant current output unit that is equal to the number of LED arrays and whose operation is determined according to an operation presence or absence signal to output a constant current to operate each of the LED arrays; and
A control unit that is equal to the number of LED arrays and outputs the operation presence/absence signal in response to the status signal output from the comparison unit,
In response to the first state signal among the state signals output from the comparator, the control unit outputs an operation signal to operate the constant current output unit, and in response to the second state signal among the state signals output from the comparator. The control unit outputs a no-operation signal to stop the entire operation of the constant current output unit,
The control unit,
first resistance;
second resistance;
third resistance;
fourth resistance;
a first switch having a first terminal connected to the third resistor, a second terminal connected to ground, and a third terminal connected to the second resistor and the fourth resistor; and
a second switch with a first terminal connected to the fourth resistor, a second terminal connected to a power supply voltage, and a third terminal connected to a control terminal of the constant current output unit; An LED driving device comprising: According to clause 1,
A switching unit that is equal to the number of LED arrays and is switched on when the constant current output unit operates, and switched off when the constant current output unit stops operating. The method of claim 1, wherein the constant current output unit,
An LED driving device comprising an operational amplifier, the first input terminal of which is connected to a reference voltage, the second input terminal of which is connected to the output terminal of the constant current output unit, and the control terminal of which is connected to the output terminal of the control unit. According to clause 3,
The first resistor has a first terminal connected to the power voltage and a second terminal connected to the output terminal of the comparator,
The second resistor has a first terminal connected to the power voltage and a second terminal connected to the first switch,
The third resistor has a first terminal connected to the output terminal of the comparator and a second terminal connected to the first terminal of the first switch,
The fourth resistor has a first terminal connected to the second terminal of the second resistor and a second terminal connected to the second switch,
The first terminal of the first switch is connected to the output terminal of the comparison unit through the third resistor,
The second switch is an LED driving device in which the third terminal, which is a collector, is connected to the control terminal of the operational amplifier. According to clause 4,
The first switch and the second switch have opposite polarities.

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