Light source driving device

Abstract

The light source driving device according to the embodiment includes a light source unit, a constant current driving unit connected to the light source unit and including a first switching element such that a constant current is supplied to the light source unit based on a switching operation of the first switching element, a driving control unit outputting a switching signal to control the first switching element constituting the constant current driving unit, an abnormal condition detection unit detecting an abnormal condition of the light source unit and an abnormal condition of the driving control unit and outputting a control signal based on the detection result, and a protection circuit unit selectively operating based on the control signal output from the abnormal condition detection unit to stop the operation of the constant current driving unit and the light source unit.

Description

[Technical Field]

[0001] The embodiments relate to a light source driving device, and more particularly to a light source driving device that can detect various abnormal states of a light source unit and stop driving the light source unit when the abnormal state is detected. [Background technology]

[0002] 2. Description of the Related Art Lighting devices are devices that can provide light or adjust the amount of light used in various fields. For example, lighting devices are applied to various fields such as vehicles and buildings to brighten the interior or exterior of the building.

[0003] Recently, light-emitting devices have been used as lighting sources. These light-emitting devices, such as light-emitting diodes (LEDs), have advantages such as lower power consumption, a semi-permanent lifespan, fast response speed, safety, and environmental friendliness compared to existing light sources such as fluorescent lamps and incandescent lamps. These light-emitting diodes are applied to various optical assemblies such as various display devices, indoor and outdoor lamps, etc.

[0004] Generally, lamps of various colors and shapes are used in vehicles, and recently, lamps using light emitting diodes (LEDs) have been proposed as vehicle light sources. For example, LEDs are used in vehicle headlights, taillights, turn signals, daytime running lights, sidelights, etc.

[0005] A driving device for controlling the driving of the lamp receives a PWM (Pulse Width Modulation) type constant current from a power supply (not shown) and drives the LED using the constant current, and the brightness of the LED is controlled by adjusting the intensity of the applied current.

[0006] Meanwhile, recently, a symmetrical control method using transistors has been adopted to construct low-cost light source driving devices, and when multiple LEDs are connected in series or / and in parallel, a linear circuit is used to control each LED. However, such a linear circuit has limitations in controlling LEDs at high currents, and therefore a constant current circuit using a transistor is often used.

[0007] However, in the case of the constant current circuit using the transistor as described above, there is no detection circuit that can detect various abnormal state events that occur in the driving environment of the LED. As a result, even when the abnormal state events as described above are detected, the LED continues to be driven, which causes reliability problems. Summary of the Invention [Problem to be solved by the invention]

[0008] The present embodiment aims to provide a light source driving device that can detect various abnormal conditions that may occur in the driving environment of a light emitting diode and protect the light emitting diode from these abnormal conditions.

[0009] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the embodiments belong from the following description. [Means for solving the problem]

[0010] The light source driving device according to the embodiment includes a light source unit; a constant current driving unit connected to the light source unit, including a first switching element, and configured to supply a constant current to the light source unit based on the switching operation of the first switching element; a driving control unit that outputs a switching signal to control the first switching element constituting the constant current driving unit; an abnormal condition detecting unit that detects an abnormal condition of the light source unit and an abnormal condition of the driving control unit and outputs a control signal based on the detection result; and a protection circuit unit that selectively operates based on the control signal output from the abnormal condition detecting unit to stop the operation of the constant current driving unit and the light source unit.

[0011] The light source unit also includes at least one of a first protection circuit unit connected to an input terminal of the light source unit and a second protection circuit unit connected to an output terminal of the light source unit.

[0012] The first protection circuit unit includes a second switching element connected to the abnormal state detection unit and performing a switching operation based on a control signal output from the abnormal state detection unit, and a third switching element connected to the second switching element and performing a switching operation based on the switching operation of the second switching element.

[0013] The second switching element includes a first base connected to the abnormal state detection unit, a first collector connected to an input terminal of the light source unit, and a first emitter connected to ground, and the third switching element includes a second base connected to the first collector of the second switching element, a second collector connected to the base of the first switching element, and a second emitter connected to ground.

[0014] In addition, the second switching element turns on when the control signal is at a first level and turns off when the control signal is at a second level, the third switching element turns off when the control signal is at the first level and turns on when the control signal is at the second level, and the first switching element maintains a turned-off state when the third switching element is turned on.

[0015] The first protection circuit unit includes a first Zener diode having a first cathode connected to the input terminal of the light source unit and an anode connected to the second base terminal of the third switching element.

[0016] In addition, the first Zener diode is turned on when a second voltage higher than a first voltage is applied to the input terminal of the light source unit, the third switching element is changed to a turned-on state in response to the turning-on of the first Zener diode, and the first switching element maintains a turned-off state when the third switching element is turned on.

[0017] The second protection circuit unit includes a fourth switching element connected to the abnormal condition detection unit and performing a switching operation based on a control signal output from the abnormal condition detection unit, a fifth switching element connected to the fourth switching element and performing a switching operation based on the switching operation of the fourth switching element, and a sixth switching element connected to the fifth switching element and performing a switching operation based on the switching operation of the fifth switching element.

[0018] The fourth switching element includes a third base connected to the abnormal state detection unit, a third collector connected to the fifth switching element, and a third emitter connected to ground. The fifth switching element includes a fourth base connected to the third collector of the fourth switching element, a fourth collector connected to the output of the light source unit and the sixth switching element, and a fourth emitter connected to ground. The sixth switching element includes a source connected to the output of the light source unit, a gate connected to the fourth collector of the fifth switching element, and a drain connected to ground.

[0019] In addition, the fourth switching element turns on when the control signal is at a first level and turns off when the control signal is at a second level; the fifth switching element turns off when the control signal is at the first level and turns on when the control signal is at the second level; the sixth switching element turns off when the control signal is at the first level and turns on when the control signal is at the second level; and when the sixth switching element is in a turned-on state, the current applied to the light source unit flows through a path including the sixth switching element.

[0020] The abnormal state detection unit also includes a first AND gate that receives the first and second state signals and outputs a first control signal based on the first and second state signals, and a second AND gate that receives the first and third state signals and outputs a second control signal based on the first and third state signals.

[0021] Further, the first status signal is a status signal of a power supply supplied to the drive control unit, the second status signal is a status signal of a clock signal output from the drive control unit, and the third status signal includes a status signal corresponding to an open state or a short state of the light source unit.

[0022] The protection circuit unit includes the first protection circuit unit and the second protection circuit unit, the first AND gate outputs the first control signal to one of the first protection circuit unit and the second protection circuit unit, and the second AND gate outputs the second control signal to the other of the first protection circuit unit and the second protection circuit unit. [Effects of the Invention]

[0023] The embodiment may improve the operational reliability of the light source unit. For example, the embodiment may include a first protection circuit unit disposed at an input end of the light source unit. The first protection circuit unit operates to stop the light emission operation of the light source unit when an abnormal state of the light source unit, an abnormal state of the power supply supplied to the drive controller, or an abnormal state of the clock signal provided from the drive controller is detected. As a result, the embodiment may solve reliability problems that may arise when the light source unit continues to operate in various abnormal states, thereby protecting each component circuit of the light source driving device. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a block diagram showing a configuration of a light source driving device according to an embodiment; [Figure 2] 1. FIG. 4 is a block diagram specifically showing another embodiment of the light source unit of FIG. [Figure 3] 2 is a circuit diagram specifically showing the light source driving device shown in FIG. 1. FIG. [Figure 4] 4 is a diagram illustrating an example of the operation of the light source unit illustrated in FIG. 3; [Figure 5] 2 is a circuit diagram specifically illustrating the abnormal state detector shown in FIG. 1; [Figure 6] 4 is a diagram showing an operation waveform of the light source driving device according to the embodiment; [Figure 7] FIG. 10 is a block diagram showing the configuration of a light source driving device according to another embodiment. [Figure 8] 8 is a circuit diagram specifically showing the light source driving device shown in FIG. 7. FIG. [Figure 9] FIG. 10 is a circuit diagram specifically showing a light source driving device according to yet another embodiment. [Figure 10] 1 is a top view of a vehicle to which a lamp having a light source driving device according to an embodiment is applied; [Figure 11] 1 is an example in which the light source driving device according to the embodiment is disposed at the front of a vehicle. [Figure 12] 1 is an example in which the lighting driving device according to the embodiment is disposed at the rear of a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] However, the technical concept of the present invention is not limited to the described embodiments, but can be embodied in various different forms, and one or more of the components of the embodiments can be selectively combined or substituted within the scope of the technical concept of the present invention.

[0027] Furthermore, unless otherwise clearly and specifically stated, terms (including technical and scientific terms) used in the embodiments of the present invention shall be interpreted as meanings that are commonly understood by a person having ordinary knowledge in the technical field to which the present invention belongs, and commonly used terms, such as terms defined in a dictionary, shall be interpreted in light of the contextual meaning of the relevant technology.

[0028] Furthermore, terms used in the examples of the present invention are intended to describe the examples and are not intended to limit the present invention. In this specification, the singular form can also include the plural form unless otherwise specified in the phrase, and when it is stated as "at least one (or more) of A and B and C," it can include one or more of all possible combinations of A, B, and C.

[0029] Furthermore, in describing components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are used to distinguish the component from other components, and do not limit the nature or order of the components. Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it may include not only a case where the component is directly coupled, coupled, or connected to the other component, but also a case where the component is "coupled," "coupled," or "connected" by yet another component between the component and the other component.

[0030] Furthermore, when it is stated that something is formed or disposed "above or below" a component, "above or below" does not only mean that the two components are in direct contact with each other, but also means that one or more other components are formed or disposed between the two components. Furthermore, when it is expressed as "above or below," it can mean not only an upper direction but also a lower direction based on one component.

[0031] FIG. 1 is a block diagram showing the configuration of a light source driving device according to an embodiment, and FIG. 2 is a block diagram specifically showing another embodiment of the light source unit of FIG.

[0032] Referring to FIG. 1, the light source driving device includes a light source unit 110, a constant current driving unit 120, a driving control unit 130, a first protection circuit unit 140, and an abnormal state detection unit 150.

[0033] The light source unit 110 may include at least one light emitting diode.

[0034] When the light source unit 110 includes a plurality of light emitting diodes, the plurality of light emitting diodes may be connected in series or in parallel to each other.

[0035] The light source unit 110 may include a light emitting package in which a light emitting diode chip is packaged. The light emitting diode chip may emit at least one of blue, green, red, ultraviolet (UV), and infrared light.

[0036] The light source unit 110 may be mounted on a vehicle to form a lamp. For example, one or more light sources 110 may be disposed at at least one of the front, rear, and side of the vehicle. For example, the light source unit 110 may be used as a front lamp of the vehicle. For example, the light source unit 110 may emit light to function as at least one of a headlight, a turn signal light, a daytime running light, a high beam, a low beam, and a fog lamp. For example, the light source unit 110 may emit light in conjunction with the opening of a vehicle door to provide additional functions such as a welcome light or a celebration effect. For example, the light source unit 110 may be used as a rear lamp that emits light to function as at least one of a side light, a brake light, and a turn signal light.

[0037] The light source unit 110 is driven by an applied current. For example, a pulse-type current is applied to the driving device of the embodiment from a main control module (not shown). For example, the current may be a constant current. To this end, the input terminal of the light source unit 110 may include a constant current input unit 100a to which the constant current is input from the main control module.

[0038] A PWM (Pulse Width Modulation) type current is applied to the constant current input unit 100a. The main control module may be a module that controls a specific main lamp among multiple lamps provided in a vehicle. For example, the main control module may be, but is not limited to, a headlamp control module (HCM) that controls a headlamp. Also, although the current output from a separate module is applied to the light source unit 110 of the light source driving device in the above description, the present invention is not limited to this. Also, although the current supplied from a separate module is applied to the light source unit 110 of the light source driving device in the above description, the present invention is not limited to this. For example, the light source driving device may further include a converter (not shown) connected to a vehicle battery (not shown) and for driving the light source unit 110 using power supplied by discharging the battery.

[0039] The light source unit 110 is driven by the current applied from the constant current input unit 100a and can output light of a specific color and brightness.

[0040] The light source unit 110 may include one light emitting diode or, alternatively, may include a plurality of light emitting diodes. For example, when the light source unit 110 includes a plurality of light emitting diodes, the plurality of light emitting diodes are simultaneously turned on or off.

[0041] For example, the light source unit 110 may be divided into a plurality of channels. For example, the light source unit 110 may include a first light source unit 111 of a first channel including a plurality of light emitting diodes, a second light source unit 112 of a second channel including a plurality of light emitting diodes, and a third light source unit 113 of a third channel including a plurality of light emitting diodes. In this case, each of the first to third light source units 111, 112, and 113 may be configured with a single light emitting diode, or alternatively, may have a structure in which two or more light emitting diodes are connected in series.

[0042] The plurality of light emitting diodes constituting the first light source unit 111 are simultaneously turned on and turned off. The plurality of light emitting diodes constituting the second light source unit 112 are simultaneously turned on and turned off. The plurality of light emitting diodes constituting the third light source unit 113 are simultaneously turned on and turned off. For example, the plurality of light emitting diodes in the first light source unit 111, the second light source unit 112, and the third light source unit 113 constituting each channel can be driven by an applied current to simultaneously emit light, and are simultaneously turned off when the applied current is cut off.

[0043] Furthermore, the first light source unit 111, the second light source unit 112, and the third light source unit 113, each including a plurality of light emitting diodes, are simultaneously turned on and off.

[0044] Alternatively, the first light source unit 111, the second light source unit 112, and the third light source unit 113 may be turned on and off at different times. For example, the plurality of light emitting diodes constituting the first light source unit 111 may be turned on at a first time point, the plurality of light emitting diodes constituting the second light source unit 112 may be turned on at a second time point different from the first time point, and the plurality of light emitting diodes constituting the third light source unit 113 may be turned on at a third time point different from the first and second time points.

[0045] Meanwhile, the plurality of light emitting diodes constituting each of the first light source unit 111, the second light source unit 112, and the third light source unit 113 may be turned on sequentially or in stages. For example, the first light source unit 111 may include first to third light emitting diodes. The first to third light emitting diodes may be turned on at different times. For example, at least one of the first to third light emitting diodes may be turned on at a first time point, and at least one of the first to third light emitting diodes may be turned on at a second time point that is later than the first time point. For example, the first to third light emitting diodes may be turned on at a predetermined time interval. As a result, the light source unit 110 in this embodiment may provide an animation effect by sequentially turning on the plurality of light emitting diodes. Meanwhile, the first to third light emitting diodes may be turned on at different times and turned off at the same time. For the above-described staged light emitting operation, each of the first light source unit 111, the second light source unit 112, and the third light source unit 113 may have the following circuit configuration.

[0046] FIG. 2 is a detailed configuration diagram of one of the first light source unit 111, the second light source unit 112, and the third light source unit 113. As shown in FIG.

[0047] 2, at least one of the first light source unit 111, the second light source unit 112, and the third light source unit 113 may include a first light emitting diode 210 and a second light emitting diode 220. The first light emitting diode 210 and the second light emitting diode 220 may be connected in series. Although at least one of the first light source unit 111, the second light source unit 112, and the third light source unit 113 is illustrated as including two light emitting diodes, this is not limiting. For example, at least one of the first light source unit 111, the second light source unit 112, and the third light source unit 113 may include three or more light emitting diodes, and the light emitting diodes may be turned on sequentially or in stages to implement an animation effect.

[0048] The light source unit may also include a detector connected to both ends of each light emitting diode (LED) to detect an abnormal state of each LED. For example, the light source unit may operate in an abnormal state. For example, the first and second LEDs 210 and 220 may experience an abnormal state such as an open circuit or a short circuit during operation. The first detector 230 may detect an abnormal state that may occur in the first LED 210. The second detector 240 may detect an abnormal state that may occur in the second LED 210. The abnormal state may include an open circuit or a short circuit of the LED. The first detector 230 may detect a first voltage across the first LED 210. The second detector 240 may detect a second voltage across the second LED 220.

[0049] The light source unit may also include individual switches. The individual switches are individually connected to the respective light emitting diodes. The individual switches may turn on and off current flowing through the respective light emitting diodes. For example, each individual switch may include a first individual switch 250. The first individual switch 250 is connected to both ends of the first light emitting diode 210 and may turn on and off current flowing through the first light emitting diode 210. The individual switches may also include a second individual switch 260. The second individual switch 260 is connected to both ends of the second light emitting diode 220 and may turn on and off current flowing through the second light emitting diode 220. The first individual switch 250 may supply current to the first light emitting diode 210 in a turned-on state and may block current flowing through the first light emitting diode 210 in a turned-off state. Similarly, the second individual switch 260 may supply current to the second light emitting diode 220 in a turned-on state and may block current flowing through the second light emitting diode 220 in a turned-off state.

[0050] The light source unit may also include an individual control unit 270. The individual control unit 270 may control the light-emitting operation of the first light-emitting diode 210 by controlling the switching state of the first individual switch 250. The individual control unit 270 may also control the light-emitting operation of the second light-emitting diode 220 by controlling the switching state of the second individual switch 260. The individual control unit 270 may also be connected to an abnormal state detection unit 150 of the light source driving device and transmit abnormal state information of the first light-emitting diode 210 and the second light-emitting diode 220 to the abnormal state detection unit 150. For example, the individual control unit 270 may transmit a high signal to the abnormal state detection unit 150 when the first voltage sensed through the first detection unit 230 and the second voltage sensed through the second detection unit 240 are both within a normal range. In addition, the individual control unit 270 can transmit a low signal to the abnormal state detection unit 150 when at least one of the first voltage sensed through the first detection unit 230 and the second voltage sensed through the second detection unit 240 is outside the normal range.

[0051] As described above, the high-spec light source unit capable of realizing the animation effect includes a sensing unit, an individual switch, and an individual control unit, thereby enabling individual control of each light emitting diode.

[0052] Meanwhile, the constant current driver 120 can control the light source unit 110 with a constant current. For example, the constant current driver 120 can include a switching element connected to an output terminal of the light source unit 110.

[0053] A switching element constituting the constant current driver 120 may control the magnitude of the current flowing to the light source unit 110. For example, the constant current driver 120 may perform a switching operation to supply a constant current to the light source unit 110. To this end, the constant current driver 120 may feedback the current flowing through the light source unit 110 and itself. The constant current driver 120 may then vary the output amplitude based on the feedback result to maintain a constant current. For example, the constant current driver 120 may generate a PWM (Pulse Width Modulation) control signal for linearly controlling brightness dimming of the light source unit 110. For example, the constant current driver 120 may control the duty ratio of the PWM control signal for brightness dimming of the light source unit 110. The constant current driver 120 may also perform a switching operation based on the PWM control signal to function as a load that absorbs a voltage difference caused by an increase or decrease in voltage applied to the light source unit 110.

[0054] The driving control unit 130 may generate the PWM control signal and control the constant current driving unit 120 based on the PWM control signal. The driving control unit 130 may include, but is not limited to, a microcomputer. The driving control unit 130 may provide a clock signal and cause the overall operation of the light source driving device to be performed based on the clock signal. For example, the driving control unit 130 may cause the constant current driving unit 120 to be controlled based on the clock signal.

[0055] The embodiment includes a first protection circuit unit 140. The first protection circuit unit 140 is disposed between the constant current input unit 100a and the light source unit 110. When an abnormal state occurs during operation of the light source unit 110, the first protection circuit unit 140 can stop the operation of the light source unit 110 (e.g., cut off the current flowing to the light source unit 110). To this end, the first protection circuit unit 140 is disposed between the input terminal of the light source unit 110 and the constant current driver 120. When the first protection circuit unit 140 detects the abnormal state, it transmits a corresponding signal to the constant current driver 120. The constant current driver 120 can perform a switching operation based on the signal provided from the first protection circuit unit 140 to cut off the current flowing to the light source unit 110. For example, the constant current driver 120 can operate in a turn-off state based on the signal provided from the first protection circuit unit 140 to cut off the current applied to the light source unit 110.

[0056] The abnormal state detector 150 detects various abnormal states that may occur during operation of the light source unit 110 and outputs a control signal corresponding to whether or not the abnormal state is detected.

[0057] For example, the abnormal condition detection unit 150 may output a low-level control signal when an abnormal condition is detected during operation of the light source unit 110. The low-level control signal output from the abnormal condition detection unit 150 may be a signal for operating the first protection circuit unit 140. For example, the first protection circuit unit 140 may include at least one switching element. The switching element of the first protection circuit unit 140 may operate in a turn-on state based on the low-level control signal output from the abnormal condition detection unit 150. When the switching element of the first protection circuit unit 140 operates in a turn-on state, the switching element of the constant current driver 120 may operate in a turn-off state. When the switching element of the constant current driver 120 operates in a turn-off state, the operation of the light source unit 110 is stopped.

[0058] The specific circuit configuration of the light source driving device and the connections therebetween will be described below.

[0059] FIG. 3 is a circuit diagram specifically showing the light source driving device shown in FIG. 1, FIG. 4 is a diagram showing an example of the operation of the light source unit shown in FIG. 3, FIG. 5 is a circuit diagram specifically showing the abnormal state detection unit shown in FIG. 1, and FIG. 6 is a diagram showing the operating waveforms of the light source driving device according to the embodiment.

[0060] 3, the light source unit 110 may be divided into a plurality of channels. For example, the light source unit 110 may include a first light source unit 111, a second light source unit 112, and a third light source unit 113, which are divided into different channels. Each of the light source units divided into the different channels may include at least one light emitting diode. In this embodiment, the first light source unit 111, the second light source unit 112, and the third light source unit 113 each include two light emitting diodes, but this is not limited thereto. For example, at least one of the first light source unit 111, the second light source unit 112, and the third light source unit 113 may include only one light emitting diode, and the other may include three or more light emitting diodes.

[0061] The constant current driver 120 includes a switching element. The constant current driver 120 may include a switching element connected to the output terminal of the light source unit of each channel. For example, the constant current driver 120 may include a first switching element Q1 connected to the output terminal of the first light source unit 111. The constant current driver 120 may also include a second switching element Q2 connected to the output terminal of the second light source unit 112. The constant current driver 120 may also include a third switching element Q3 connected to the output terminal of the third light source unit 113.

[0062] The first switching element Q1 selectively performs a switching operation to supply a constant current to the first light source 111. The first switching element may include, but is not limited to, an npn-type transistor. The collector of the first switching element Q1 is connected to the output of the first light source 111. The emitter of the first switching element Q1 is connected to ground. The base of the first switching element Q1 is connected to the output of the first protection circuit 140. The base of the first switching element Q1 is also connected to the driving control unit 130. Thus, under normal operating conditions, the first switching element Q1 can be turned on or off based on a switching signal applied from the driving control unit 130. Under abnormal operating conditions, the first switching element Q1 can be turned off based on a signal output from the first protection circuit 140.

[0063] The second switching element Q2 selectively performs a switching operation to supply a constant current to the second light source 112. The collector of the second switching element Q2 is connected to the output of the second light source 112. The emitter of the second switching element Q2 is connected to ground. The base of the second switching element Q2 is connected to the output of the first protection circuit 140. The base of the second switching element Q2 is also connected to the driving control unit 130. Thus, the second switching element Q2 can be turned on or off in response to a switching signal applied from the driving control unit 130 under normal operating conditions. The second switching element Q2 can be turned off in response to a signal output from the first protection circuit 140 under abnormal operating conditions.

[0064] The third switching element Q3 selectively performs a switching operation to supply a constant current to the third light source 113. The collector terminal of the third switching element Q3 is connected to the output terminal of the third light source 113. The emitter terminal of the third switching element Q3 is connected to ground. The base terminal of the third switching element Q3 is connected to the output terminal of the first protection circuit 140. The base terminal of the third switching element Q3 is also connected to the driving control unit 130. As a result, the third switching element Q3 can be turned on or off in response to a switching signal applied from the driving control unit 130 under normal operating conditions. In addition, the third switching element Q3 can be turned off in response to a signal output from the first protection circuit 140 under abnormal operating conditions.

[0065] Meanwhile, the driving control unit 130 may include a first resistor R1, a second resistor R2, and a third resistor R3. The first resistor R1 is disposed between the emitter of the first switching element Q1 and ground. The second resistor R2 is disposed between the emitter of the second switching element Q2 and ground. The third resistor R3 is disposed between the emitter of the third switching element Q3 and ground.

[0066] Meanwhile, the first protection circuit unit 140 may include a plurality of resistors, capacitors, Zener diodes, diodes, and switching elements. For example, the first protection circuit unit 140 may include a third switching element Q4, a fifth switching element Q5, a first Zener diode ZD1, a diode, a first capacitor C1, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9.

[0067] The cathode terminal of the first Zener diode ZD1 is connected between the output terminal of the constant current input unit 100a and the input terminal of the light source unit 110. The anode terminal of the first Zener diode ZD1 is connected to one terminal of a fourth resistor R4.

[0068] One end of the fourth resistor R4 is connected to the anode terminal of the first Zener diode ZD1, and the other end is connected to one end of the fifth resistor R5.

[0069] One end of a fifth resistor R5 is connected to the other end of the fourth resistor R4, and the other end is connected to the base of a fourth switching element Q4 and one end of a sixth resistor R6.

[0070] One end of a sixth resistor R6 is connected to the base of the fourth switching element Q4 and the other end of the fifth resistor R5, and the other end is connected to ground.

[0071] One end of the seventh resistor R7 is connected to the output terminal of the abnormal state detector 150, and the other end is connected to one end of the eighth resistor R8 and the base of the fifth switching element Q5.

[0072] An eighth resistor R8 has one end connected to the other end of the seventh resistor R7 and the base of the fifth switching element Q5, and the other end connected to ground.

[0073] The ninth resistor R9 has one end connected to the input terminal of the light source unit 110 and the other end connected to the anode terminal of the diode.

[0074] The fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, and the ninth resistor R9 are provided for the operational reliability of each element constituting the first protection circuit unit 140. For example, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, and the ninth resistor R9 can reduce the current or voltage applied to the location where they are located.

[0075] Meanwhile, the base of the fourth switching element Q4 of the first protection circuit 140 is connected between the other end of the fifth resistor R5 and one end of the sixth resistor R6. For example, the base of the fourth switching element Q4 is connected to the anode of the first Zener diode ZD1 via the fourth resistor R4 and the fifth resistor R5. The collector of the fourth switching element Q4 is connected to the constant current driver 120. Specifically, the collector of the fourth switching element Q4 is connected to the bases of the switching elements constituting the constant current driver 120. For example, the collector of the fourth switching element Q4 is connected to the base of the first switching element Q1, the base of the second switching element Q2, and the base of the third switching element Q3.

[0076] The base of the fifth switching element Q5 is connected to one end of the eighth resistor R8 and the other end of the seventh resistor R7. Specifically, the base of the fifth switching element Q5 is connected to the output of the abnormal condition detector 150 via the seventh resistor R7. The fifth switching element Q5 is turned on or off based on the first control signal CS1 and / or the second control signal CS2 output through the output of the abnormal condition detector 150.

[0077] The collector terminal of the fifth switching element Q5 is connected to the other terminal of the ninth resistor and the anode terminal of the diode, and the emitter terminal of the fifth switching element Q5 is connected to ground.

[0078] In addition, the anode of the diode is connected to the other end of the ninth resistor R9 and the collector of the fifth switching element Q5, and the cathode is connected to the base of the fourth switching element Q4.

[0079] One end of a first capacitor C1 is connected to the base terminal of the fourth switching element Q4, the other end of the fifth resistor R5, one end of the sixth resistor R6 and the cathode terminal of the diode, and the other end is connected to ground.

[0080] Meanwhile, the light source driving device may include a tenth resistor R10 and an eleventh resistor R11. The tenth resistor R10 is disposed between the constant current input unit 100a and the light source unit 110. The eleventh resistor R11 is disposed between the input terminal of the light source unit 110 and the constant current driving unit 120.

[0081] In the light source driving device described above, when a constant current is applied from the constant current input unit 100a under normal operating conditions, the applied constant current is applied to the light source unit 110. For example, if the light source unit 110 is configured with three channels, the applied constant current is equally distributed and applied to each of the three channels. For example, if the applied constant current is 1 A, a constant current of 1 / 3 A is applied to each of the light source units of the three channels. The constant current driving unit 120 can perform a switching operation to turn on and off the constant current applied to the light source unit of each channel. As a result, under the normal operating conditions described above, a constant current is applied to the light source unit 110, and light emission can be performed using the applied constant current.

[0082] Meanwhile, the first protection circuit unit 140 is activated when an abnormal state is detected during operation of the light source unit 110, and can turn off the switching elements of the constant current driver unit 120.

[0083] For example, the first protection circuit unit 140 may operate when the light source unit 110 is open. That is, the light source unit 110 is configured with a plurality of channels, and when a light source unit corresponding to any one of the plurality of channels is open, the operation of the first protection circuit unit 140 is initiated.

[0084] To this end, the cathode of the first Zener diode ZD1 of the first protection circuit 140 is connected to the input terminal of the light source unit 110. At this time, when the light source unit 110 is in a normal state, a first voltage is applied to the input terminal of the light source unit 110, for example, the cathode terminal of the first Zener diode ZD1. When an open circuit occurs in the light emitting diode of the light source unit of at least one channel among the plurality of channels constituting the light source unit 110, a second voltage greater than the first voltage is applied to the cathode terminal of the first Zener diode ZD1.

[0085] The first Zener diode ZD1 may maintain a turned-off state when the first voltage is applied to the cathode terminal. The first Zener diode ZD1 may selectively turn on when the voltage applied to the cathode terminal increases. For example, the first Zener diode ZD1 may selectively turn on when a voltage equal to or greater than a preset threshold voltage is applied to the cathode terminal. For example, the first Zener diode ZD1 may turn on when a second voltage higher than the first voltage is applied to the cathode terminal.

[0086] Meanwhile, the fourth switching element Q4 is turned off when the light source unit 110 operates in a normal state. The fourth switching element Q4 is selectively turned on when the light source unit 110 operates in an abnormal state. For example, the fourth switching element Q4 may maintain a turned-off state when the first Zener diode ZD1 is turned off. When the first Zener diode ZD1 is turned on due to an increase in the voltage at the input terminal of the light source unit 110, the fourth switching element Q4 is turned on in conjunction with the switching operation of the first Zener diode ZD1. The collector of the fourth switching element Q4 is connected to the constant current driver 120. That is, the collector of the fourth switching element Q4 is connected to the base terminals of the first switching element Q1, the second switching element Q2, and the third switching element Q3 that constitute the constant current driver 120. Therefore, when the fourth switching element Q4 is turned on, the first switching element Q1, the second switching element Q2, and the third switching element Q3 are turned off, respectively. When the first switching element Q1, the second switching element Q2, and the third switching element Q3 are turned off, the current applied to the light source 110 is cut off.

[0087] As described above, the first protection circuit unit 140 in this embodiment includes the first Zener diode ZD1 connected to the input terminal of the light source unit 110. The first Zener diode ZD1 is turned on in response to an open circuit in a specific channel of the light source unit 110, thereby detecting an abnormal state of the light source unit 110. The fourth switching element Q4 is turned on when an abnormal state caused by the first Zener diode ZD1 being turned on is detected, thereby turning off the constant current driver 120.

[0088] Meanwhile, as described above, the first protection circuit unit 140 includes a connection terminal connected to the abnormal state detection unit 150. The connection terminal is connected to the base terminal of the fifth switching element Q5 via the seventh resistor R7.

[0089] At this time, the fifth switching element Q5 maintains a turn-on state under normal operating conditions. The fifth switching element Q5 can be turned off when a control signal corresponding to the detection of a specific abnormal state is transmitted through the abnormal state detector 150. For example, the abnormal state detector 150 can output a first level control signal when the light source driving device operates normally and output a second level control signal when the light source driving device operates abnormally. The fifth switching element Q5 can maintain a turn-on state when the first level control signal is input from the abnormal state detector 150 through the input terminal. Alternatively, the fifth switching element Q5 can be turned off when the second level control signal is input from the abnormal state detector 150 through the input terminal.

[0090] At this time, when the fifth switching element Q5 is changed to a turn-off state, the current applied from the constant current driver 120 is applied to the fourth switching element Q4 via the ninth resistor R9 and the diode. The fourth switching element Q4 is turned on by the current applied via the ninth resistor R9 and the diode. For example, the fourth switching element Q4 may operate in a turn-off state before the current is applied and then operate in a turn-on state when the current is applied. When the fourth switching element Q4 operates in a turn-on state, the first switching element Q1, the second switching element Q2, and the third switching element Q3 of the constant current driver 120 connected to the fourth switching element Q4 are each turned off. Therefore, when a second level control signal indicating an abnormal state is applied to the first protection circuit 140, the fifth switching element Q5 and the fourth switching element Q4 can each turn off the switching elements of the constant current driver 120. In the embodiment, when the light source driving device operates in an abnormal state, the constant current driving unit 120 operates in a turn-off state, thereby stopping the operation of the light source unit 110.

[0091] Meanwhile, the first protection circuit unit 140 receives control signals corresponding to various abnormal state detection results at its input terminal.

[0092] For example, the input terminal of the first protection circuit unit 140 may include a first abnormal state corresponding to an open state or short state of the light source unit 110, a second abnormal state corresponding to an interruption of power supplied to the driving control unit 130, and a third abnormal state corresponding to no clock signal being generated in the driving control unit 130.

[0093] That is, when any one of the above-defined abnormal states occurs, the abnormal state detector 150 outputs the second level control signal. When the second level control signal is output, the fifth switching element Q5 of the first protection circuit 140 is turned off, and the fourth switching element Q4 is turned on, thereby stopping the operation of the constant current driver 120 and the light source 110.

[0094] The detailed configuration of the abnormal state detector 150 and the characteristics of the output of the second level control signal will now be described in more detail.

[0095] The abnormal condition detection unit 150 may include a plurality of AND gates. For example, the abnormal condition detection unit 150 may include a first AND gate 154 and a second AND gate 155. An output terminal OP1 of the first AND gate 154 and an output terminal OP2 of the second AND gate 155 are respectively connected to input terminals of the first protection circuit unit 140. For example, the first AND gate 154 performs a logical AND operation on signals input via input terminals IP1 and IP2 and outputs a first control signal corresponding to the logical AND operation result. For example, the second AND gate 155 performs a logical AND operation on signals input via input terminals IP3 and IP4 and outputs a second control signal corresponding to the logical AND operation result. To this end, specific signals are input to the input terminals of the first AND gate 154 and the second AND gate 154, respectively.

[0096] A power signal PSS of the driving control unit 130 is input to a first input terminal IP1 of the first AND gate 154. For example, the first input terminal IP1 of the first AND gate 154 is connected to a power signal PSS terminal 151 of the driving control unit 130.

[0097] A clock signal CLKS of the driving control unit 130 is input to a second input terminal IP2 of the first AND gate 154. For example, the second input terminal IP2 of the first AND gate 154 is connected to a clock signal CLKS terminal 152 of the driving control unit 130.

[0098] Thus, the first AND gate 154 can output a first control signal based on the power signal of the driving control unit 130 input through the first input terminal IP1 and the clock signal of the driving control unit 130 input through the second input terminal IP2. For example, the first AND gate 154 can output a first control signal of a first level when the power signal of the driving control unit 130 and the clock signal of the driving control unit 130 are normally input. The first AND gate 154 can also output a first control signal of a second level when an abnormal state occurs in which at least one of the power signal of the driving control unit 130 and the clock signal of the driving control unit 130 is not input. The first control signal is provided to the input terminal of the first protection circuit unit 140. For example, when the first control signal of the first level is output through the first AND gate 154, the fifth switching element Q5 of the first protection circuit unit 140 can maintain a turn-on state. For example, when the first control signal of the second level is output through the first AND gate 154, the fifth switching element Q5 of the first protection circuit unit 140 is changed to a turn-off state.

[0099] A power signal PSS of the driving control unit 130 is input to a third input terminal IP3 of the second AND gate 155. For example, the third input terminal IP3 of the second AND gate 155 is connected to a power signal PSS terminal 151 of the driving control unit 130.

[0100] A state detection signal of the light source unit 110 is input to a fourth input terminal IP4 of the second AND gate 155. For example, the fourth input terminal IP4 of the second AND gate 155 is connected to a feedback signal FS output terminal 153 of a sensing block that senses the state of the light source unit 110. For example, the fourth input terminal IP4 of the second AND gate 155 is connected to a feedback terminal (not shown) of the individual control unit 270 described in FIG. 2. For example, the individual control unit 270 may receive a sensing signal that senses an open state or a short state of the first light emitting diode 210 and the second light emitting diode 220 via the first sensing unit 230 and the second sensing unit 240, and provide the received sensing signal to the fourth input terminal IP4 of the second AND gate 155. For example, the sensing signal may include a first sensing signal indicating that the first light emitting diode 210 and the second light emitting diode 220 are both in a normal state and a second sensing signal indicating that at least one of the first light emitting diode 210 and the second light emitting diode 220 is in an abnormal state.

[0101] Meanwhile, the second AND gate 155 may output a second control signal based on the power signal of the driving control unit 130 input through the third input terminal IP3 and the state detection signal of the light source unit 110 input through the fourth input terminal IP4. For example, the second AND gate 155 may output a second control signal of a first level when the power signal of the driving control unit 130 and the first detection signal from the individual control unit 270 of the light source unit 110 are input. The second AND gate 155 may output a second control signal of a second level when the power signal of the driving control unit 130 is not normally input or when the second detection signal is input from the individual control unit 270 of the light source unit 110. The second control signal of the first level or the second control signal of the second level is provided to the input terminal of the first protection circuit unit 140. For example, when the second control signal of the first level is output through the second AND gate 155, the fifth switching element Q5 of the first protection circuit unit 140 may maintain a turn-on state. For example, when the second control signal of the second level is output through the second AND gate 155, the fifth switching element Q5 of the first protection circuit unit 140 is changed to a turn-off state.

[0102] As described above, in the embodiment, various abnormal states of the light source driving device can be detected through the abnormal state detection unit 150. Also, in the embodiment, the operation of the light source unit 110 can be stopped by detecting an abnormal state through the first protection circuit unit 140. Furthermore, in the embodiment, an open state or short state of the light source unit 110 can be detected based on a detection signal detected by the light source unit 110. Alternatively, a protection operation corresponding to the open state of the light source unit 110 can be directly performed through the first Zener diode ZD1. That is, as described above, the light source unit 110 may or may not have an animation function. If the light source unit 110 does not have an animation function, the light source unit 110 does not include the individual switch, detection unit, and individual control unit described above. In this case, the first Zener diode ZD1 selectively turns on in response to a voltage applied to the input terminal of the light source unit 110, thereby stopping the operation of the constant current driver 120 and the light source unit 110 when the light source unit 110 is in an open state.

[0103] 6, in this embodiment, the current or voltage applied to the light source unit 110 changes depending on the output of the first control signal and the second control signal. Waveform A in FIG. 6 shows the magnitude of the current flowing through the light source unit 110, waveform B shows the first control signal output from the first AND gate 154, and waveform C shows the second control signal output from the second AND gate 155.

[0104] For example, in the embodiment, during a first interval TS1 between the initial time point T0 and the first time point T1, the first control signal CS1 may maintain a first level corresponding to a high level, and the second control signal CS2 may maintain a second level corresponding to a high level. When both the first control signal CS1 and the second control signal CS2 maintain a high level, the light source unit 110 may operate normally. That is, when the light source unit 110 is in a normal state, a power signal is normally input to the driving control unit 130, and a clock signal is normally output from the driving control unit 130, both the first control signal CS1 and the second control signal CS2 maintain a high level. Under these conditions, the constant current driving unit 120 operates normally, thereby supplying a constant current to the light source unit 110.

[0105] Meanwhile, in this embodiment, the level of the first control signal CS1 changes from a high level to a low level at the first time point T1. For example, at the first time point T1, an abnormality may occur in the power signal supplied to the driving control unit 130 or the clock signal output from the driving control unit 130. In such a case, the first AND gate 154 changes the level of the first control signal CS1 to a second level (e.g., a low level). At this time, when the level of the first control signal CS1 changes from a high level to a low level, the first protection circuit unit 140 begins to operate. For example, when the level of the first control signal CS1 changes to a low level, the fifth switching element Q5 is turned off and the fourth switching element Q4 is turned on. As a result, the constant current driver 120 is turned off, thereby stopping the light emission of the light source unit 110. For example, no current may be supplied to the light source unit 110 during a second interval TS2 corresponding to the first time point T1 to the second time point T2.

[0106] Meanwhile, in this embodiment, the level of the first control signal CS1 changes from a low level to a high level at the second time point T2. For example, a power signal that was not supplied to the driving control unit 130 or a clock signal that was not output from the driving control unit 130 at the second time point T2 returns to a normal state. In this case, the first AND gate 154 changes the level of the first control signal to a high level again. As the level of the first control signal changes to a high level, the constant current driver 120 resumes operation, and a constant current is supplied to the light source unit 110 under the control of the constant current driver 120. Meanwhile, the light source unit 110 can operate normally during a third interval TS3 corresponding to the period from the second time point T2 to the third time point T3 during which the first control signal and the second control signal are both maintained at a high level.

[0107] Meanwhile, in this embodiment, the level of the second control signal CS2 changes from a high level to a low level at the third time point T3. For example, at the third time point T3, the power signal supplied to the driving control unit 130 is not normally supplied or an abnormal state is detected in the light source unit 110. In this case, the second AND gate 155 changes the level of the second control signal CS2 to a second level (e.g., a low level). At this time, when the level of the second control signal CS2 changes from a high level to a low level, the first protection circuit unit 140 begins to operate. For example, when the level of the second control signal CS2 changes to a low level, the fifth switching element Q5 is turned off and the fourth switching element Q4 is turned on. As a result, the constant current driver 120 is turned off, thereby stopping the light emission of the light source unit 110. For example, no current may be supplied to the light source unit 110 during a fourth interval TS4 corresponding to the third time point T3 to the fourth time point T4.

[0108] Meanwhile, in this embodiment, the level of the second control signal CS2 changes from a low level to a high level at the fourth time point T4. For example, a power signal that was not supplied to the driving control unit 130 at the fourth time point T4 is resupplied, or the light source unit 110 returns to a normal state. In this case, the first AND gate 154 changes the level of the first control signal from a low level to a high level. As the level of the first control signal changes to a high level, the constant current driver 120 restarts its operation, and a constant current is supplied to the light source unit 110 under the control of the constant current driver 120. Meanwhile, the light source unit 110 may operate normally during a fifth interval TS5, from a fifth time point T5, at which the first control signal and the second control signal are both maintained at a high level, to a time point at which the level of the first control signal or the second control signal changes.

[0109] FIG. 7 is a block diagram showing the configuration of a light source driving device according to another embodiment, and FIG. 8 is a circuit diagram specifically showing the light source driving device shown in FIG.

[0110] 7, the light source driving device of another embodiment includes a light source unit 110, a constant current driving unit 120, a driving control unit 130, an abnormal state detection unit 150, and a second protection circuit unit 160. The light source unit 110, the constant current driving unit 120, the driving control unit 130, and the abnormal state detection unit 150 shown in FIG. 7 are substantially the same as those shown in FIG. 1, and therefore will be given the same fail rating and will not be described in detail.

[0111] The first protection circuit unit 140 in FIG. 3 is disposed between the constant current input unit 100 a and the input terminal of the light source unit 110 , and controls the operations of the constant current driver unit 120 and the light source unit 110 .

[0112] Alternatively, the second protection circuit unit 160 is disposed at the output end of the light source unit 110. The second protection circuit unit 160 is connected to the abnormal condition detection unit 150, and receives a first control signal and a second control signal from the abnormal condition detection unit 150. The second protection circuit unit 160 is activated when the level of at least one of the first control signal and the second control signal is a second level (e.g., a low level), thereby stopping the operation of the constant current driver 120 and the light source unit 110.

[0113] The second protection circuit unit 160 may include a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a second Zener diode ZD2, a sixth switching element Q6, a seventh switching element Q7, and an eighth switching element M1. The sixth switching element Q6 and the seventh switching element Q7 may be transistors. The eighth switching element M1 may be a MOSFET (Metal Oxide-Semiconductor Field Effect Transistor). For example, the eighth switching element M1 may be, but is not limited to, a P-type MOSFET.

[0114] One end of the twelfth resistor R12 is connected to the output terminal of the abnormal state detector 150, and the other end is connected to the base terminal of the sixth switching element Q6 and one end of the second capacitor C2.

[0115] The thirteenth resistor R13 has one end connected to the output terminal of the light source unit 110 and the other end connected to the collector terminal of the seventh switching element Q7 and the gate terminal of the eighth switching element M1.

[0116] One end of the fourteenth resistor R14 is connected to the output terminal of the light source unit 110 and the cathode terminal of the Zener diode ZD1, and the other end is connected to the base terminal of the sixth switching element Q6 and the base terminal of the seventh switching element Q7.

[0117] The sixth switching element Q6 has a collector terminal connected to the base terminal of the seventh switching element Q7 and the other terminal of the fourteenth resistor R14, a base terminal connected to the other terminal of the twelfth resistor R12 and one terminal of the second capacitor C2, and an emitter terminal connected to ground.

[0118] The seventh switching element Q7 has a collector connected to the gate of the eighth switching element M1, a base connected to the collector of the sixth switching element Q6, and an emitter connected to ground.

[0119] The eighth switching element M1 has a source terminal connected to the output terminal of the light source unit 110, a gate terminal connected to the other terminal of the thirteenth resistor R13, the anode terminal of the second Zener diode ZD2, and the collector terminal of the seventh switching element Q7, and a drain terminal connected to ground.

[0120] The second Zener diode ZD2 has a cathode connected to the output terminal of the light source unit 110, one terminal of the thirteenth resistor R13, and one terminal of the fourteenth resistor R14, and an anode connected to the collector terminal of the seventh switching element Q7 and the gate terminal of the eighth switching element M1.

[0121] One end of the second capacitor C2 is connected to the other end of the twelfth resistor R12 and the base of the sixth switching element Q6, and the other end is grounded.

[0122] The second protection circuit unit 160 configured as above operates as follows.

[0123] The second protection circuit unit 160 receives a first control signal CS1 and a second control signal CS2 from the abnormal condition detection unit 150. For example, the first control signal CS1 may include a first control signal of a first level and a first control signal of a second level, as described above, and the second control signal CS2 may include a second control signal of a first level and a second control signal of a second level.

[0124] The second protection circuit unit 160 is activated when the level of at least one of the first control signal CS1 and the second control signal CS2 is the second level (or low level), thereby stopping the operation of the constant current driver 120 and the light source unit 110.

[0125] On the other hand, when the first control signal CS1 and the second control signal CS2 are both at the first level (or high level), the sixth switching element Q6 operates in a turned-on state, the seventh switching element Q7 operates in a turned-off state, and the eighth switching element M1 operates in a turned-off state. At this time, since the eighth switching element M1 is in a turned-off state, the constant current applied from the constant current input unit 100a is applied to the light source unit 110 under the control of the constant current driver 120.

[0126] On the other hand, when the level of at least one of the first control signal CS1 and the second control signal CS2 is at the second level (or low level), the sixth switching element Q6 is turned off, and the seventh switching element Q7 is turned on. At this time, when the seventh switching element Q7 is turned on, the eighth switching element M1 is also turned on. Furthermore, when the eighth switching element M1 is turned on, the light source unit 110 may operate in a short-circuit state. For example, when the eighth switching element M1 is turned on, the anode and cathode of the light emitting diode constituting the light source unit 110 are short-circuited. As a result, the current applied from the constant current input unit 100a is not applied to the light source unit 110 but flows through the eighth switching element M1. As a result, the light source unit 110 may cease lighting.

[0127] As described above, the second protection circuit 160 can stop the light emission operation of the light source 110 without changing the switching state of the switching element constituting the constant current driver 120. This is because the second protection circuit 160 is connected to the output terminal of the light source 110, not the input terminal.

[0128] As described above, in the embodiment, depending on the arrangement state of the light source unit 110 constituting the light source driving device, at least one of the first protection circuit unit 140 and the second protection circuit unit 160 can be applied to stop the light emission operation of the light source unit 110.

[0129] For example, the light source unit 110 may be configured with a plurality of channels, and the plurality of channels may constitute different lamps in a vehicle. For example, some of the plurality of channels constituting the light source unit 110 may be used as tail lights, other may be used as turn signal lights, and the remaining may be used as brake lights.

[0130] In this case, the light source driving device includes a plurality of circuit boards separated from each other, and the light source units 110 of the above-described multiple channels are arranged separately on the plurality of circuit boards. The plurality of circuit boards are connected to each other via a connecting member such as a wire. Meanwhile, the first protection circuit unit 140 is arranged on a circuit board on which one of the plurality of light source units is arranged. In this case, in order to control the operation of a light source unit arranged on another circuit board through the first protection circuit unit, control must be performed through limited control pins, which may cause problems with operational reliability. Therefore, in this embodiment, the operation of the light source unit 110 is controlled using at least one of the first protection circuit unit 140 and the second protection circuit unit 160 depending on the arrangement of the light source unit 110.

[0131] FIG. 9 is a circuit diagram specifically showing a light source driving device according to still another embodiment.

[0132] Referring to FIG. 9, the light source driving device may include a constant current input unit 100a, a light source unit 110, a constant current driving unit 120, a driving control unit 130, a first protection circuit unit 140, an abnormal state detection unit 150, and a second protection circuit unit 160.

[0133] That is, the light source driving device in the embodiment includes both the first protection circuit unit 140 shown in Fig. 3 and the second protection circuit unit 160 shown in Fig. 8. Therefore, in the embodiment, the first protection circuit unit 140 and the second protection circuit unit 160 can be used to control the light source unit 110 depending on the situation.

[0134] For example, in an embodiment, under a first condition, the operation of the light source unit 110 can be controlled using the first protection circuit unit 140. Also, in an embodiment, under a second condition, the operation of the light source unit 110 can be controlled using the second protection circuit unit 160.

[0135] For example, the abnormal condition detector 150 may include a first AND gate 154 and a second AND gate 155 .

[0136] The output terminal of one of the first AND gate 154 and the second AND gate 155 is connected to the first protection circuit unit 140. The output terminal of the other of the first AND gate 154 and the second AND gate 155 is connected to the second protection circuit unit 160. For example, the first protection circuit unit 140 is connected to the output terminal of the first AND gate 154. The second protection circuit unit 160 is connected to the output terminal of the second AND gate 155. In this case, the first protection circuit unit 140 receives a first control signal CS1 output from the first AND gate 154. The second protection circuit unit 160 receives a second control signal CS2 output from the second AND gate 155. Therefore, the first protection circuit unit 140 can receive a first control signal of a first level or a second control signal of a second level output from the first AND gate 154. The first protection circuit unit 140 is activated when the first control signal of the second level is received to stop the operation of the constant current driver 120 and the light source unit 110. The second protection circuit unit 160 can receive the second control signal of the first level or the second control signal of the second level output from the second AND gate 155. The second protection circuit unit 160 is activated when the second control signal of the second level is received to short-circuit the light source unit 110 and control the current to flow through the eighth switching element M1.

[0137] In some embodiments, the operational reliability of the light source unit can be improved. For example, in some embodiments, a first protection circuit unit disposed at an input end of the light source unit may be included. The first protection circuit unit operates to stop the light emission operation of the light source unit when an abnormal state of the light source unit, an abnormal state of the power supply supplied to the drive controller, or an abnormal state of the clock signal provided from the drive controller is detected. As a result, in some embodiments, reliability issues that may arise due to the light source unit continuing to operate in various abnormal states as described above can be resolved, and each component circuit of the light source driving device can be protected.

[0138] FIG. 10 is a top view of a vehicle to which a lamp having a light source driving device according to the embodiment is applied, FIG. 11 is an example in which a light source driving device according to the embodiment is arranged at the front of the vehicle, and FIG. 12 is an example in which a lighting driving device according to the embodiment is arranged at the rear of the vehicle.

[0139] 10 to 12, the lighting driving device according to the embodiment can be applied to lamps of the vehicle 2000. One or more lamps are disposed at at least one of the front, rear, and side of the vehicle 2000. The lighting driving device can be provided in various shapes such as curved or straight lines and can be applied to lamps disposed in various areas of the vehicle 2000.

[0140] 11, for example, the lamp may be applied to a front lamp 2100 of a vehicle 2000. The front lamp 2100 may include at least one lamp module including a first cover member 2110 and the lighting device 1000. The first cover member 2110 may accommodate the lighting driving device.

[0141] The front lamp 2100 can provide multiple functions by controlling the driving timing of a lighting driver included in at least one lamp module. For example, the front lamp 2100 can include a first lamp module 2120 and a third lamp module 2130 that provide at least one function of a headlight, a turn signal light, a daytime running light, a high beam, a low beam, and a fog lamp by emitting light from the light source unit 110 of the lighting driver. In addition, the front lamp 2100 can provide additional functions such as a welcome light or a celebration effect when the driver opens the vehicle door.

[0142] 12, the lamp may be applied to a vehicle rear lamp 2200. The rear lamp 2200 may include at least one lamp module including a second cover member 2210 and the lighting driver. The second cover member 2210 may accommodate the lighting driver.

[0143] The rear lamp 2200 can provide multiple functions by controlling the driving timing of the light source unit included in at least one lamp module. For example, the rear lamp 2200 can include a second lamp module 2220 that provides at least one function of a side light, a brake light, and a turn signal light by emitting light from the light source unit 110 of the light source driving device.

[0144] In some embodiments, the operational reliability of the light source unit can be improved. For example, in some embodiments, a first protection circuit unit disposed at an input end of the light source unit may be included. The first protection circuit unit operates to stop the light emission operation of the light source unit when an abnormal state of the light source unit, an abnormal state of the power supply supplied to the drive controller, or an abnormal state of the clock signal provided from the drive controller is detected. As a result, in some embodiments, reliability issues that may arise due to the light source unit continuing to operate in various abnormal states as described above can be resolved, and each component circuit of the light source driving device can be protected.

[0145] The features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by a person skilled in the art to which the embodiment belongs. Therefore, the contents related to such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0146] Furthermore, although the above description has focused on the embodiments, these are merely examples and are not intended to limit the present invention. A person skilled in the art to which the present invention pertains may make various modifications and applications not exemplified above within the scope of the essential characteristics of the present embodiments. For example, each component specifically presented in the embodiments may be modified and implemented. Differences related to such modifications and applications should be construed as being included within the scope of the present invention as defined by the appended claims.

Claims

1. a light source unit; a constant current driver connected to the light source unit, the constant current driver including a first switching element, and configured to supply a constant current to the light source unit based on a switching operation of the first switching element; a drive control unit that outputs a switching signal to control the first switching element that constitutes the constant current drive unit; an abnormality detection unit that detects an abnormal state of the light source unit and an abnormal state of the drive control unit and outputs a control signal based on the detection result; a protection circuit unit selectively operating based on a control signal output from the abnormal state detection unit to stop the operation of the constant current driver and the light source unit, the abnormal state detection unit includes an AND gate that receives a plurality of state signals corresponding to the light source unit and the drive control unit, and outputs a control signal based on the received plurality of state signals; the protection circuit unit includes a first protection circuit unit connected to an input terminal of the light source unit, The first protection circuit unit a second switching element connected to the abnormal state detection unit and performing a switching operation based on a control signal output from the abnormal state detection unit; a third switching element connected to the second switching element and performing a switching operation based on a switching operation of the second switching element;

2. The light source driving device of claim 1 , wherein the protection circuit further comprises a second protection circuit connected to an output terminal of the light source.

3. 3. The light source driving device of claim 2, wherein the second switching element includes a first base connected to the abnormal state detection unit, a first collector connected to an input terminal of the light source unit, and a first emitter connected to ground, and the third switching element includes a second base connected to the first collector of the second switching element, a second collector connected to the base of the first switching element, and a second emitter connected to ground.

4. the second switching element is turned on when the control signal is at a first level; When the control signal is at a second level, it turns off; the third switching element is turned off when the control signal is at the first level, and turned on when the control signal is at the second level; The light source driving device of claim 3 , wherein the first switching element maintains a turned-off state when the third switching element is turned on.

5. 5. The light source driving device of claim 3, wherein the first protection circuit unit includes a first Zener diode having a first cathode terminal connected to an input terminal of the light source unit and an anode terminal connected to the second base terminal of the third switching element.

6. the first Zener diode is turned on when a second voltage higher than a first voltage is applied to an input terminal of the light source unit; the third switching element is changed to a turn-on state in response to the turn-on of the first Zener diode; The light source driving device of claim 5 , wherein the first switching element maintains a turned-off state when the third switching element is turned on.

7. The second protection circuit unit a fourth switching element connected to the abnormal state detector and performing a switching operation based on a control signal output from the abnormal state detector; a fifth switching element connected to the fourth switching element and performing a switching operation based on a switching operation of the fourth switching element; The light source driving device according to claim 2 , further comprising: a sixth switching element connected to the fifth switching element and performing a switching operation based on a switching operation of the fifth switching element.

8. the fourth switching element includes a third base connected to the abnormal state detector, a third collector connected to the fifth switching element, and a third emitter connected to ground; the fifth switching element includes a fourth base connected to the third collector of the fourth switching element, a fourth collector connected to an output of the light source unit and the sixth switching element, and a fourth emitter connected to ground; 8. The light source driving device of claim 7, wherein the sixth switching element includes a source terminal connected to an output terminal of the light source unit, a gate terminal connected to the fourth collector terminal of the fifth switching element, and a drain terminal connected to ground.

9. the fourth switching element is turned on when the control signal is at a first level; When the control signal is at a second level, it turns off; the fifth switching element is turned off when the control signal is at the first level, and turned on when the control signal is at the second level; the sixth switching element is turned off when the control signal is at the first level, and turned on when the control signal is at the second level; The light source driving device of claim 8 , wherein when the sixth switching element is turned on, the current applied to the light source unit flows through a path including the sixth switching element.

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