KR20170089997A - An apparatus for driving a light emitting device - Google Patents

Abstract

The present invention relates to a device for driving a light emitting element which drives a light emitting unit including a plurality of channels, wherein each of the channels includes a plurality of light emitting elements connected to each other in series. The device comprises: a power supply unit for providing driving power for a first node to which one ends of a plurality of channels are commonly connected; constant current driving units corresponding to the channels; and a control unit for controlling the driving power. Each of the constant current driving units includes a sensing resistor, and a transistor connected between the sensing resistor and a corresponding one of the channels, and outputs detection voltage in accordance with a result of detecting voltage between a contact point of the corresponding one of the channels and the transistor, and a contact point of the transistor and the sensing resistor. The control unit determines each of the channels as a normal channel, a short-circuit channel, or an open-circuit channel on the basis of detection voltages corresponding to the channels provided by the constant current driving units, and generates an alarming signal or controls driving voltage on the basis of the number of short-circuit light emitting elements of the short-circuit channel, and the existence or the number of the open-circuit channels.

Description

TECHNICAL FIELD [0001] The present invention relates to a light emitting element driving apparatus,

The embodiment relates to a light-emitting element driving apparatus.

In recent years, there has been a growing interest in LED lighting, which has a brightness comparable to that of an illumination device such as an incandescent lamp, while operating with low power consumption. In particular, research and development of an illumination driving apparatus for driving LED lighting by controlling a current so that a constant current flows through the LED illumination is actively under way.

In a general LED lighting apparatus, the light emitting surface can be easily seen with the naked eye, and it is possible to easily find a lighting failure due to an abnormal operation of the LED. However, LED modules mounted inside equipment or systems, such as hardeners and exposure devices, can not be identified even if lighting failures occur because it is difficult to identify the lighting by the naked eye. Therefore, in such products, it is possible to detect defects after they occur or to make defects through periodic inspections.

Embodiments can monitor a short-circuit of light emitting devices included in a plurality of channels connected in parallel and a disconnection of a plurality of channels in real time, and generate an alarm signal according to a result of monitoring. A light emitting device driving device capable of preventing breakage of a light emitting device due to an overcurrent and shortening of its service life is provided.

An exemplary embodiment of the present invention relates to a light emitting device driving apparatus for driving a light emitting unit including a plurality of channels and a plurality of light emitting devices connected in series, A power supply for supplying driving power to the power supply unit; Constant current drivers corresponding to the plurality of channels; And a control unit for adjusting the driving power, wherein each of the constant current driving units includes a sensing resistor and a transistor connected between the sensing resistor and a corresponding one of the plurality of channels, And outputs a detection voltage according to a result of detecting a voltage between a corresponding one of the plurality of transistors, a contact point of the transistor, and a contact point of the transistor and the sensing resistor, and the control unit responds to the plurality of channels provided from the constant current drivers A short channel, or a single channel based on the detection voltages of the short-circuited channels, based on the number of the short-circuited luminous elements of the short channel, the presence of the single channel or the number of the single- Thereby generating an alarm signal or adjusting the drive voltage.

Wherein the controller determines that the detected channel is the single channel when the detected voltage is less than the first voltage and determines that the detected channel is the normal channel when the detected voltage is greater than or equal to the first voltage and less than the second voltage, The first voltage is less than or equal to a voltage between a source and a drain of the transistor when the transistor is turned on and the second voltage is a voltage between the plurality of channels Which is smaller than one operating voltage of the light emitting element included in any one of them.

The controller may generate an alarm signal when any one of the plurality of channels is a single channel.

The controller may control the power supply unit to maintain the driving voltage when the shorting channel includes a predetermined number of short-circuit light emitting elements.

The controller may generate the alarm signal when the shorting panel includes a predetermined number of short-circuit light emitting elements.

The predetermined number may be one.

Wherein the control unit controls the driving voltage of the constant current driving units corresponding to the remaining channels other than the single channel to be the predetermined target voltage when the detected voltages detected by the voltage detecting units of the constant current driving units corresponding to the remaining channels, The power supply unit can be controlled to reduce the power consumption.

The target voltage may be a detection voltage of the normal channel.

Wherein the control unit maintains the drive voltage when the detection voltage is equal to or higher than the second voltage and less than the third voltage and generates the alarm signal when the detection voltage exceeds the third voltage, The voltage may be a voltage greater than an operation voltage of one light emitting element included in any one of the plurality of channels.

Wherein each of the constant current drivers includes: a first input terminal to which a constant current control signal is inputted; an amplifier including a sensing resistor and a second input terminal connected to a contact point of the transistor; and an output terminal connected to a gate of the transistor; And a voltage detector for outputting the detection voltage according to a result of detecting a voltage between the second node and the third node, wherein the second node is connected to one end of the transistor and a corresponding one of the plurality of channels And the third node may be a node to which the other end of the transistor, one end of the sensing resistor, and the second input terminal of the amplifier are connected.

The embodiment can monitor a short-circuit of light emitting devices included in a plurality of channels connected in parallel and a disconnection of a plurality of channels in real time, and generate an alarm signal according to a result of the monitoring. It is possible to prevent breakage of the light emitting element and shortening the life span of the light emitting element.

1 shows a configuration diagram of a lighting apparatus according to an embodiment.
Fig. 2 shows a configuration diagram of a lighting apparatus according to another embodiment.
FIG. 3 shows an embodiment of the first constant current driving part corresponding to the first channel shown in FIG.
Fig. 4 shows an embodiment of the power supply unit shown in Fig.
5 is a flowchart showing an embodiment of the operation of the control unit shown in FIG.
6 is a flowchart showing another embodiment of the operation of the control unit shown in Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. In the description of the embodiments, it is to be understood that each layer (film), region, pattern or structure may be referred to as being "on" or "under" a substrate, each layer It is to be understood that the terms " on "and " under" include both " directly "or" indirectly " do. In addition, the criteria for the top / bottom or bottom / bottom of each layer are described with reference to the drawings. The same reference numerals denote the same elements throughout the description of the drawings.

Fig. 1 shows a configuration diagram of a lighting apparatus 100 according to an embodiment.

Referring to FIG. 1, the lighting apparatus 100 includes a light emitting portion 101 and a light emitting element driving device 102 for driving the light emitting portion 101.

The light emitting portion 101 includes a plurality of channels (channels, CH1 to CHn, natural number of n> 1).

Each of the plurality of channels (CH1 to CHn, natural number of n> 1) includes a plurality of light emitting elements (D1 to Dk, k> 1 as a natural number) connected in series. For example, each of the plurality of light emitting devices (a natural number of D1 to Dk, k> 1) may be a light emitting diode.

One end of a plurality of channels (CH1 to CHn, n> 1) is connected to each other and a node to which one ends of a plurality of channels (CH1 to CHn, n> 1) N1). At this time, one end of each of the plurality of channels (CH1 to CHn, n> 1) may be a positive terminal of the first light emitting device D1 of each of the channels CH1 to CHn.

The light emitting element driving apparatus 102 includes a power supply unit 110, a channel current detection block 120, and a control unit 130.

The power supply unit 110 supplies a DC power (for example, a DC voltage) to the light emitting unit 101. The power supply unit 110 can adjust the level of the direct current power supply VD based on the power supply control signal Pc provided from the control unit 130. [

FIG. 4 shows an embodiment of the power supply unit 110 shown in FIG.

4, the power supply unit 110 may include an AC power source 510, an EMI filter 520, a rectifier 530, a power factor correcting unit 540, and a voltage generator 130.

The AC power supply unit 510 provides an AC signal AC.

At this time, the AC signal AC may be an AC voltage, and / or an AC current.

The EMI (ElectroMagnetic Interference) filter 520 is for blocking external electromagnetic noise and removes noise included in the AC signal AC supplied from the AC power source unit 510, for example, conductive noise. EMI filter 520 may be implemented to include at least one of a capacitor, a transformer, and an inductor.

The rectifier 530 rectifies the AC signal AC having the electromagnetic noise removed by the EMI filter 520 and provides a ripple current (VR) according to the rectified result.

For example, the rectifier 530 may full-wave rectify the AC signal AC and output a rectified signal according to the result of the full-wave rectification. That is, the rectified signal may be a signal in which the AC signal AC is full-wave rectified.

The rectifier 530 may be implemented as a radio wave diode bridge circuit including four diodes connected by bridges, but is not limited thereto.

The power factor correction unit 540 corrects the power factor of the rectified signal by adjusting the phase difference between the voltage and the current of the rectified signal, and outputs the rectified signal having the corrected power factor.

The voltage generating unit 550 converts the level of the rectified signal whose power factor has been corrected by the power factor correcting unit 540 based on the power source control signal Pc and outputs the level converted direct current signal VD, .

The DC signal VD output from the voltage generating unit 550 is provided to the light emitting unit 101. For example, the direct current signal VD output from the voltage generator 550 may be provided to the first node N1 to which one ends of the plurality of channels CH1 to CHn are connected. The voltage supplied from the voltage generating unit 550 to the first node N1 of the light emitting unit 101 may be the driving voltage VD of the light emitting unit 101. [

The voltage generating unit 550 may be implemented as a converter capable of converting a DC level. For example, the voltage generating unit 550 may be implemented to include at least one of a DC-DC converter, a resonant LLC half bridge converter, a flyback converter, or a buck converter .

The channel current detection block 120 detects channel currents I1 to In, a natural number of n> 1 flowing in each of the plurality of channels CH1 to CHn, and detects the detected channel currents I1 to In, n> 1) to the control unit 130. The control unit 130 controls the operation of the control unit 130,

The channel current detection block 120 may include a plurality of channel current detectors 120-1 to 120-n corresponding to the plurality of channels CH1 to CHn.

Each of the plurality of channel current detectors 120-1 to 120-n is connected to one end of a corresponding one of the plurality of channels CH1 to CHn and a corresponding one of the plurality of channels CH1 to CHn It is possible to detect one channel current and generate information (S1 to Sn, n> 1 natural number) related to the channel current according to the detected result. For example, information on the channel current (S1 to Sn, natural number of n> 1) may be the current value of the channel current.

The control unit 130 determines each of the plurality of channels CH1 to CHn as a single line channel, a normal channel, or a short channel based on the information on the channel currents (S1 to Sn, n> 1 natural number).

Here, the normal channel may mean a channel in which the light emitting devices included in the channel are short-circuited or not. The short channel may mean a channel in which at least one of the light emitting devices included in the channel is short-circuited. The disconnection channel may refer to a channel in which at least one of the light emitting devices included in the channel is disconnected.

The control unit 130 generates an alarm signal As based on the number of the short-circuited luminous elements of the short-circuit channel, the presence or absence of the single-channel or the number of the single- (Pc). The level of the driving voltage VD provided to the light emitting portion 101 can be adjusted based on the power supply signal Pc.

2 shows a configuration diagram of a lighting apparatus 200 according to another embodiment. The same reference numerals as in Fig. 1 denote the same components, and a description of the same components will be simplified or omitted.

Referring to FIG. 2, the lighting apparatus 200 includes a light emitting portion 101 and a light emitting element driving portion 102-1.

The light emitting device driving unit 102-1 includes a power supply unit 110, a plurality of constant current driving units 210-1 to 210-n, and a controller 130. [

The plurality of constant current drivers 210-1 to 210-n correspond to the plurality of channels CH1 to CHn and allow a constant current to flow through the plurality of channels.

For example, each of the plurality of constant current drivers 210-1 to 210-n is connected to a corresponding one of the plurality of channels CH1 to CHn, so that a constant current flows through a corresponding one of the channels .

FIG. 3 shows an embodiment of the first constant current driving part 210-1 corresponding to the first channel CH1 shown in FIG. Although the first constant current driving part 210-1 will be described with reference to FIG. 3, the second to the n constant current driving parts 210-2 to 210-n also have the same configurations as the first constant current driving part 210-1 And the description of the first constant current driving part 210-1 may be applied equally.

Referring to FIG. 3, the first constant current driving part 210-1 includes a sensing resistor Rsen and a transistor 310 connected between a sensing resistor and a corresponding one of the plurality of channels. The first constant current driving part 210-1 detects a voltage between a corresponding one of the plurality of channels and the contact N2 of the transistor 310 and the contact N2 of the sensing resistor Rsen And outputs a detection voltage Vs1 according to a result.

The first constant current driving part 210-1 includes a first input terminal 321 to which the constant current control signal Pc is inputted, a second input terminal connected to the contact N3 of the sensing resistor Rsen and the transistor 310, And an output terminal 323 connected to the gate of the transistor 310. The detection voltage Vs1 is determined according to the result of detecting the voltage between the second node N2 and the third node N3, And a voltage detector 330 for outputting a voltage. The constant current control signal Vref may be provided from the control unit 130. [

The second node is a node to which one end of the transistor 310 and a corresponding one of the plurality of channels are connected. The third node N3 is connected to the other end of the transistor 310, one end of the sensing resistor Rsen, (The second input terminal 322 of the second node 320).

The amplifier 320 amplifies the constant current control signal Vref and the voltage of the third node N3, and outputs an amplified signal according to the amplified result. For example, the constant current control signal Vref provided from the controller 130 of FIG. 1 may be an analog signal such as a pulse width modulation (PWM) signal or a direct current voltage.

Amplifier 320 may be implemented as an Operational Amplifier, but is not limited thereto. For example, the first input terminal 321 may be a positive input terminal (+) of an operational amplifier, and the second input terminal 322 may be a negative input terminal (-) of an operational amplifier. However, the present invention is not limited thereto.

The first constant current driving part 210-1 may further include a smoothing circuit 340 connected between the output terminal 323 of the amplifier 320 and the gate of the transistor 310.

The constant current control signal Vref provided from the control unit 130 is a pulse width modulation (PWM) signal and the constant current control for the light emitting unit 101 is performed based on the duty ratio of the PWM signal A ripple component may be present in the current flowing in the light emitting portion 101 and flicker may occur in the light emitting portion 101. [

The smoothing circuit 340 smoothes the signal Pw provided from the control unit 130 and provides a constant current control signal which is an analog signal in the form of a DC signal whose ripple component is removed according to the smoothed result to the gate of the transistor 310 do.

The current flowing in the light emitting portion 101 due to the constant current control signal Vset1 generated by the smoothing circuit 340 can decrease the ripple component. The embodiment can control the constant current to the light emitting part 101 by the level value of the constant current control signal Vset1 which is an analog signal, not the duty ratio of the PWM signal, thereby reducing or eliminating the occurrence of flicker of the light emitting part 101 can do.

For example, the smoothing circuit 340 includes a first resistor R1 connected between the output terminal 323 of the amplifier 320 and the gate, an output terminal 323 of the amplifier 320, and a second input of the amplifier 323, A second resistor R2 and a third resistor R3 connected between the connection node of the first resistor R1 and the transistor 310 and the third node and a capacitor C1 and a second resistor R2 connected in series between the terminals 322, However, the present invention is not limited thereto and may be implemented in various forms including a resistor, a capacitor, or an inductor.

The transistor 310 is connected between one end of the sensing resistor Rsen and the other end of a corresponding one of the plurality of channels CH1 to CHn (for example, CH1) and connected to the output terminal 323 of the amplifier 310 And is turned off or turned off based on the output of the comparator. For example, the transistor 310 may be implemented as an FET transistor or a BJT transistor.

For example, the transistor 310 has a drain connected to the other end of the corresponding channel (e.g., CH1), a source connected to one end of the sensing resistor Rsen, and a source connected to the gate of the amplifier 320 The transistor 310 is connected to the other end of the corresponding channel CH1 and the sensing resistor Rsen of the other terminal of the amplifier 320 based on the output of the amplifier 320, May be implemented in various forms.

And the other end of the corresponding one channel (e.g., CH1) may be the negative terminal of the last light emitting element Dn of the channel CH1. The sensing resistor Rsen is connected between the transistor 310 and the ground power supply GND.

One end of the sensing resistor Ren may be connected directly to the second input terminal 322 of the amplifier 320 and the other end may be connected to the ground power supply GND.

The current flowing through the sensing resistor Rsen can be determined by the constant current control signal Vref and the current flowing in the light emitting portion 101 can be controlled in this embodiment. According to the characteristic of the operational amplifier, since the voltage of the third node N3 becomes the constant current control signal Vref input to the first input terminal 321, a constant current can flow through the sensing resistor Rsen.

The voltage detector 330 detects the voltage between the second node N2 and the third node N3 and outputs a detection voltage (e.g., Vs1) according to the detected result.

For example, the voltage detection unit 330 can detect the voltage between the source and the drain of the transistor 310. [

For example, the voltage detector 330 detects a voltage of the second node N2, and provides a first sensing voltage to the controller 130. The voltage sensing unit 330 senses the voltage of the third node N3, And a second sensing unit for providing a second sensing voltage to the controller 130. [ At this time, the controller 130 may obtain the voltage between the second node N1 and the third node N3 by calculating the difference between the first sensing voltage and the second sensing voltage.

The control unit 130 controls the voltage generating unit 550 of the power supply unit 110 to generate the alarm signal As1 or adjust the driving power supply VD based on the detection voltages Vs1 to Vsn .

5 is a flowchart showing an embodiment of the operation of the control unit 130 shown in FIG.

5, the control unit 130 controls the voltage generating unit 550 of the power supply unit 110 to set and adjust the driving voltage VD to be provided to the light emitting unit 101 (S110).

For example, the control unit 130 controls the voltage generator 550 of the power supply unit 110 to set the driving voltage VD to be normally driven by the light emitting devices D1 to Dn connected in series in each channel . For example, the driving voltage VD that the light emitting devices D1 to Dn can normally drive may be a sum of the rated operating voltages of the light emitting devices of any one of the channels.

Next, the control unit 130 receives the detection voltages Vs1 to Vsn from the voltage detection unit 330 of each of the plurality of constant current driving units 210-1 to 210-n (S120). At this time, each of the detection voltages Vs1 to Vsn may be a voltage between the second node N2 and the third node N3, or may be the voltage of the second node N2 and the voltage of the third node N3 .

Next, the controller 130 determines a plurality of channels as a normal channel, a short channel, or a single channel based on the sizes of the detection voltages Vs1 through Vsn (S130).

The control unit 130 can generate the alarm signal As or maintain or adjust the set driving voltage VD based on the number of short-circuited luminous elements of the short-circuit channel, the presence or absence of the single-channel or the number of the single- ). The short-circuit light-emitting element means a light-emitting element which does not emit light due to short-circuiting.

The controller 130 can obtain the number of short-circuited luminous elements included in the channel based on the magnitude of the detected voltage. For example, the increase amount of the detection voltage can be increased in proportion to the value obtained by multiplying the number of short-circuited light-emitting elements by the operating voltage of the light-emitting element.

FIG. 6 is a flowchart showing another embodiment of the operation of the control unit 130 shown in FIG.

Referring to FIG. 6, the driving voltage VD setting and adjusting step S210 and the detecting voltage Vs1 receiving step S215 may be similarly applied to those described in FIG.

The control unit 130 compares the detected voltage (e.g., Vs1) of each channel with the first voltage V1, the second voltage V2 and the third voltage V3 to output the channels CH1 to CHn to the single- , A short channel, or a normal channel. The second voltage V2 may be greater than the first voltage and the third voltage may be greater than the second voltage.

For example, when the first detection voltage (e.g., Vs1) corresponding to the first channel (e.g., CH1) is less than the first voltage V1 (Vs1 < V1), it can be determined as a disconnection channel (S220).

For example, the first voltage V1 may be less than or equal to the voltage between the source and the drain of the transistor 310 when the transistor 310 is turned on. For example, the first voltage V1 may be 0.4V to 0.7V.

When there is a single channel among the plurality of channels CH1 to CHn, the controller 130 can generate an alarm signal. If there is a disconnection channel among the plurality of channels, an overcurrent larger than a normal current flows to the remaining channels except for the disconnection channel. Such over current may damage or shorten the life of the light emitting devices. For example, it may be a normal channel current and a current flowing in a normal channel.

The uniformity of the light output of the light emitting portion 101 may be lower than the target value due to the lighting of the light emitting elements included in the single-channel. The controller 130 may generate a notification signal to notify the breakage or shortening of the lifetime of the light emitting devices due to the over current, and the decrease of the uniformity of the light output.

Also, when there is a single-channel channel among the plurality of channels CH1 to CHn, it is determined whether the uniformity of the optical powers of the channels other than the single-channel channel satisfies the target value (225).

If the uniformity of the optical powers of the remaining channels other than the single-channel channel does not satisfy the target value, the controller 130 generates the alarm signal As at step S230.

On the other hand, when the uniformity of the optical power of the remaining channels other than the single-channel channel satisfies the desired value, the controller 130 controls the voltage generator (not shown) of the power supply unit 110 to reduce the driving voltage VD 550) (S210).

In the presence of the single-wire channel, since the overcurrent flows in the remaining channels except the single-wire channel, the detection voltages sensed by the voltage detectors of the constant current drivers corresponding to the remaining channels except the single-wire channel may increase.

The control unit 130 controls the power supply unit to decrease the magnitude of the driving voltage VD until the detection voltages detected by the voltage detection units of the constant current driving units corresponding to the channels other than the single- The voltage generating unit 550 of FIG. As the magnitude of the driving voltage VD decreases, the current flowing in the remaining channels except for the single-channel can be reduced so that the normal current flows through the remaining channels.

For example, when the magnitude of the first detection voltage (e.g., Vs1) corresponding to the first channel (e.g., CH1) is equal to or greater than the first voltage V1 and less than the second voltage V2 (V1? Vs1 < V2) The control unit 130 may determine that the first channel (e.g., CH1) is a normal channel (S235). For example, the second voltage V2 may be a voltage greater than the first voltage and less than an operating voltage (e.g., 3.5 V) of one light emitting device included in a corresponding one of the plurality of channels. For example, the second voltage V2 may be between 1V and 2V.

The control unit 130 may control the voltage generating unit 550 of the power supply unit 110 to maintain the set driving voltage VD when all of the plurality of channels are normal channels at step S240.

When the magnitude of the first detection voltage (e.g., Vs1) corresponding to the first channel (e.g., CH1) is greater than or equal to the second voltage V2, the controller 130 determines that the first channel (e.g., CH1) (S245).

For example, when the magnitude of the first detection voltage (e.g., Vs1) is equal to or greater than the second voltage V2 and less than the third voltage V3 (V2? Vs1 <V3), the controller 130 controls the first channel ) Can be discriminated to include one short-circuited light-emitting element.

For example, the third voltage V3 is greater than the operating voltage (e.g., 3.5 V) of one light emitting element included in a corresponding one of the plurality of channels, and is equal to the sum of the operating voltages of two light emitting elements ). &Lt; / RTI &gt; For example, the third voltage V3 may be 5 V to 6 V, but is not limited thereto.

When the magnitude of the first detection voltage (e.g., Vs1) corresponding to the first channel (e.g., CH1) is equal to or greater than the third voltage V3 (Vs1? V3), the controller 130 controls the first channel It is determined that the light emitting element includes two or more short-circuit light emitting elements, and an alarm signal is generated (S245).

The steps described above in Fig. 5 are performed for each of the plurality of channels based on the detection voltages Vs1 to Vsn. That is, the controller 130 may classify the plurality of channels CH1 to CHn into a normal channel, a short channel including short-circuited light emitting devices, and a single channel by performing steps S220, S235, and S245.

The control unit 130 outputs the set drive voltage VD when the plurality of channels CH1 to CHn each include a short channel including short-circuited light-emitting elements that are normal or less than a predetermined number (for example, one) The voltage generator 550 of the power supply unit 110 is controlled. In FIG. 6, the predetermined number is one, but it is not limited thereto. In another embodiment, the predetermined number may be two or more.

Even if any one of the channels includes a predetermined number (for example, one) of short-circuited luminous elements, since the uniformity of the optical power is not lower than the target value (for example, less than 90%), As a result, the embodiment does not generate the alarm signal but maintains the set driving voltage.

When the first channel includes the short-circuited light-emitting element, since the voltage across the transistor rises by the operating voltage of the short-circuited light-emitting element, the overcurrent due to the short-circuit can be prevented from occurring in the first channel.

When the uniformity of the optical power is lower than the target value when any one of the plurality of channels CH1 to CHn is a short channel including a predetermined number (for example, one) of short-circuited luminous elements, 130 can generate the alarm signal As (S245).

Also, when there are two or more disconnection channels among a plurality of channels, and the disconnection channels are located adjacent to each other, the controller 130 may generate the alarm signal As. This is because if the adjacent two channels are single-channel, the uniformity of the optical power of the light emitting unit 101 becomes a target value (for example, 90%) because all the light emitting elements included in the two adjacent channels are turned off, ). &Lt; / RTI &gt;

When the disconnection channels are not adjacent to each other, the controller 130 may not generate the alarm signal As because the uniformity of the optical power does not fall below the target value, and the remaining channels except the single- The voltage generating unit 550 of the power supply unit 110 may be controlled to decrease the driving voltage VD until the detection voltages detected by the voltage detecting units of the constant current driving units corresponding to the constant current driving units become a predetermined target voltage , Thereby preventing breakage of the light emitting device due to an overcurrent and shortening of its service life.

Embodiments can monitor a short-circuit of light emitting devices included in a plurality of channels connected in parallel and a disconnection of a plurality of channels in real time, and generate an alarm signal according to a result of monitoring. It is possible to prevent the breakage of the light emitting element due to the overcurrent and the shortening of its service life.

The features, structures, effects and the like described in the embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments can be combined and modified by other persons having ordinary skill in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

101: light emitting portion 102: light emitting element driving device
110: Power supply unit 115: EMI filter
120: Channel current detection blocks 120-1 to 120-n:
130: Controllers 210-1 to 210-n:
310: transistor 320: amplifier
330: Voltage detection unit 510: AC power supply unit
520: EMI filter 530: rectifier
540: power factor correction unit 550: voltage generating unit.

Claims (10)

A light emitting device driving apparatus for driving a light emitting unit including a plurality of channels, each of the channels including a plurality of light emitting devices connected in series,
A power supply for supplying driving power to a first node to which one ends of the plurality of channels are commonly connected;
Constant current drivers corresponding to the plurality of channels; And
And a controller for adjusting the driving power,
Each of the constant current drivers includes:
A sensing resistor, and a transistor coupled between the sensing resistor and a corresponding one of the plurality of channels, wherein a corresponding one of the plurality of channels, a contact of the transistor, And outputs a detection voltage according to the result of detection of the voltage between the electrodes,
Wherein,
A short channel, or a single channel, based on detection voltages corresponding to the plurality of channels provided from the constant current driving units,
And generates an alarm signal or adjusts the driving voltage based on the number of short-circuited luminous elements of the short-circuit channel, the presence or absence of the short-circuit channel, or the number of the short-circuit channels. The apparatus of claim 1,
When the detected voltage is less than the first voltage,
When the detected voltage is equal to or higher than the first voltage and lower than the second voltage,
When the detected voltage is equal to or higher than the second voltage,
Wherein the first voltage is less than or equal to the voltage between the source and the drain of the transistor when the transistor is turned on and the second voltage is one of the operating voltages of the light emitting devices included in any one of the plurality of channels The voltage of the light emitting element is smaller than the voltage of the light emitting element. 3. The apparatus of claim 2,
And generates an alarm signal when any one of the plurality of channels is a single channel. 3. The apparatus of claim 2,
And controls the power supply unit to maintain the driving voltage when the shorting channel includes a predetermined number of short-circuit light emitting elements. 3. The apparatus of claim 2,
And generates the alarm signal when the shorting panel includes a predetermined number of short-circuit light-emitting elements. The method according to claim 4 or 5,
Wherein the predetermined number is one. 3. The apparatus of claim 2,
The driving voltage is decreased until the detection voltages detected by the voltage detection units of the constant current driving units corresponding to the remaining channels other than the single line channel become a predetermined target voltage when there is a single line channel among the plurality of channels The light emitting element driving unit controls the power supply unit. 8. The method of claim 7,
Wherein the target voltage is a detection voltage of the normal channel. 3. The apparatus of claim 2,
The driving voltage is maintained when the detected voltage is equal to or higher than the second voltage and lower than the third voltage,
Generates the alarm signal when the detected voltage exceeds the third voltage,
Wherein the third voltage is higher than an operation voltage of one light emitting element included in any one of the plurality of channels. The plasma display apparatus according to claim 1, wherein each of the constant-
An amplifier including a first input terminal to which a constant current control signal is input, a second input terminal connected to a contact point of the sensing resistor and the transistor, and an output terminal connected to a gate of the transistor; And
And a voltage detector for outputting the detection voltage according to a result of detecting a voltage between the second node and the third node,
Wherein the second node is a node to which one end of the transistor and a corresponding one of the plurality of channels are connected and the third node is connected to the other end of the transistor, Is a node to which the light emitting element is connected.

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