KR20160080215A - Display apparatus, and control method for the same - Google Patents

Abstract

Provided are a display device which changes the ground potential of LEDs included in an LED module and supplies different driving voltages to each of the LEDs, and a control method thereof. The display device according to an embodiment may include an LED module which includes a first LED having a first driving voltage and a second LED having a second driving voltage smaller than the first driving voltage; a common anode node which connects the anode of the first LED and the anode of the second LED; and a power control part which supplies different driving voltages to the first LED and the second LED through the common anode node.

Description

DISPLAY APPARATUS AND CONTROL METHOD FOR THE SAME [0002]

A display device in which LED modules including a plurality of LEDs are arranged, and a control method thereof.

The display device may refer to a device capable of displaying a broadcast signal or image signals / image data in various formats.

Such a display device may include a display panel that displays an image using light. In this case, the display panel may be divided into a light emitting display panel that emits light by itself and a non-light emitting display panel that does not emit light by itself.

One example of an emissive display panel is an LED (Light Emitting Diode) panel. The LED panel may be arranged such that a plurality of LED modules are arranged in a predetermined direction. Since each of the plurality of LED modules corresponds to each of the pixels of the image to be displayed, each of the plurality of LED modules can emit light so as to realize the color of the corresponding pixel.

The light emitted by the plurality of LED modules may include visible light. Typically, the plurality of LED modules may include a plurality of LEDs emitting light of different wavelengths.

According to an embodiment of the present invention, a display device that supplies different driving voltages to a plurality of LEDs with different ground potentials of a plurality of LEDs included in an LED module and a control method thereof are provided.

A display device according to an exemplary embodiment includes an LED module including a first LED having a first driving voltage and a second LED having a second driving voltage lower than the first driving voltage; A common anode node connecting the anode of each of the first LED and the second LED; And a power controller for supplying different driving voltages to the first LED and the second LED through the common anode node; . ≪ / RTI >

The power control unit may apply the first driving voltage to the cathode of the common anode node and the first LED, and apply the second driving voltage to the cathode of the common anode node and the second LED.

Further, the power source control section can apply a common anode potential to the common anode node.

Also, the power source control unit applies a first ground potential, which is determined by a difference between the magnitude of the common anode potential and the magnitude of the first driving voltage, to the cathode of the first LED and adjusts the magnitude of the common anode potential and the magnitude The second ground potential, which is determined according to the difference between the first ground potential and the second ground potential, can be applied to the cathode of the second LED.

Further, the power source control section may apply a potential higher than the cathode of the first LED to the cathode of the second LED.

Further, the power supply control unit can determine the drive voltage of the second LED based on the change of the current applied to the second LED in accordance with the change of the output voltage.

Also, the power control unit may determine the driving voltage of the second LED by checking the current change applied to the second LED while reducing the voltage applied to the second LED from the driving voltage of the first LED.

The power control unit may determine the voltage applied to the second LED to be the driving voltage of the second LED at the time when the current applied to the second LED decreases.

Also, the power source control unit may divide the current received from the power source and output the first driving voltage and the second driving voltage, respectively, based on the divided current.

The power source control unit may output the first driving voltage based on the current received from the power source and output the second driving voltage based on the output first driving voltage.

The power control unit may further include: a switch for controlling the flow of the input current received from the power source to output the driving voltage supplied to the LED module; . ≪ / RTI >

According to another aspect of the present invention, there is provided a display device in which an LED module including a first LED having a first driving voltage and a second LED having a second driving voltage smaller than the first driving voltage is arranged, Applying a common anode potential to a common anode node connecting an anode of each of the first LED and the second LED; Applying a first ground potential to a cathode of the first LED such that a first drive voltage is applied to the first LED; And applying a second ground potential to the cathode of the second LED such that a second drive voltage is applied to the second LED; . ≪ / RTI >

The step of applying the first ground potential may further include determining a first ground potential according to a difference between the magnitude of the common anode potential and the first driving voltage magnitude and the step of applying the second ground potential includes: The second ground potential can be determined according to the difference between the first driving voltage magnitude and the second driving voltage magnitude.

Further, in the step of applying the second ground potential, the second ground potential higher than the first ground potential can be applied.

Determining a second driving voltage by varying a voltage supplied to the second LED; As shown in FIG.

Further, the step of determining the second driving voltage may include: changing a voltage supplied to the second LED; Confirming a current flowing in the second LED according to the changed supply voltage; And determining a second drive voltage based on the identified current; . ≪ / RTI >

Also, the step of varying the voltage supplied to the second LED may reduce the voltage supplied to the second LED from the first drive voltage.

Also, the step of determining the second driving voltage based on the identified current may determine the voltage at the time when the current applied to the second LED decreases, as the driving voltage of the second LED.

According to an embodiment of the display device and the control method thereof, a different driving voltage may be applied to each of the plurality of LEDs included in the LED module. As a result, the energy efficiency of the display device can be increased. In addition, since the heat generation inside the display device is reduced, the durability of the display device is increased, and the reliability of performance can be increased.

In addition, compatibility can be increased in the manufacture of a display device because it includes a conventional LED module in which the anode of a plurality of LEDs is connected and the cathode is separated.

1A and 1B are external views of a display device according to various embodiments.
2 is a cross-sectional view of a display device according to an embodiment.
3A and 3B are circuit diagrams of LED modules according to various embodiments.
4 is a control block diagram of a display device according to an embodiment.
FIG. 5 is a control block diagram specifically illustrating one of the LED modules of the display panel in FIG. 6 is a circuit diagram for explaining a conventional voltage supply method for an LED module.
7A and 7B are circuit diagrams for explaining a voltage supply method for an LED module according to various embodiments.
8A and 8B are circuit diagrams of a display device for explaining a power supply according to various embodiments.
9 is a flowchart of a display device control method according to an embodiment.

Hereinafter, a display device and a control method thereof will be described in detail with reference to the accompanying drawings.

1A and 1B are external views of a display device according to various embodiments.

The display device 2 may be a device for displaying an image received from the outside or a self-generated image so that the user can visually recognize the image.

As shown in Fig. 1A, the display device 2 may include a display panel 1 for displaying an image and a bubble generator 2a for protecting the outer surface of the display panel 1.

The display panel 1 is implemented with a plurality of pixels, each of which can emit light in the visible light region. The light emitted from the plurality of pixels is transmitted in the amount of the user, so that the user can recognize the image through the display panel 1. [

The bezel 2a can secure the position of the display panel 1 so that the image can be stably provided to the user and can prevent the damage of the display panel 1 from the outside.

To this end, the bezel 2a may be embodied as a durable metal, or alternatively may be embodied as a synthetic resin.

1A shows a case in which the display device 2 includes one display panel 1. FIG. One embodiment of the display device 2 comprising one display panel 1 may comprise a television.

On the other hand, the display device 3 may include a plurality of display panels 1. 1B shows a display device 3 in which a plurality of display devices 2 of FIG. 1A are disposed adjacent to each other.

As shown in FIG. 1B, when a plurality of display panels are connected, a larger image can be provided to a user. Thus, the display device 3 of FIG. 1B can be used to provide images to a large number of users through a large screen.

An embodiment of the display device 3 including a plurality of display panels 1 may include a large format display (LDF), and a signage.

The display panel 1 of FIGS. 1A and 1B may be implemented as an LED panel 200 having a plurality of LED modules 210 arranged therein. Hereinafter, the display device 2 including the LED panel 200 will be described in detail.

FIG. 2 is a cross-sectional view of a display device 2 according to one embodiment, and FIGS. 3A and 3B are circuit diagrams of an LED module 210 according to various embodiments.

Referring to FIG. 2, the display device 2 includes a display panel 200 that displays images by receiving power; A driving circuit 300 provided on the rear surface of the display panel 200 and controlling a current supplied to the display panel 200; A transparent panel 100 provided on the front surface of the display panel 200 to shield the display panel 200 from the outside; . ≪ / RTI >

The transparent panel 100 may be installed on the front surface of the display panel 200 to protect the front surface of the display panel 200 from the outside. For this purpose, the transparent panel 100 may be formed of a material having excellent durability. Since the transparent panel 100 is provided on the front surface of the display panel 200, the transparent panel 100 can be provided to transmit light emitted from the front surface of the display panel 200.

The driving circuit 300 can control an electrical signal flowing into the display panel 200. Specifically, the driving circuit 300 transmits a video signal including the video information to be displayed to the display panel 200, and the display panel 200 emits light according to the video signal so that the user can visually recognize the video have.

2 illustrates the case where the driving circuit 300 is installed on the rear surface of the display panel 200. The driving circuit 300 may be freely installed in a technical concept that does not disturb the light path generated by the display panel 200 .

The display panel 200, and the driving circuit 300 are provided outside the transparent panel 100, so that the position of the display panel 200 can be fixed. Also, a chassis 2b may be provided on the rear surface of the driving circuit 300 to be connected to the bracelet 2a. Accordingly, the transparent panel 100, the display panel 200, and the driving circuit 300 can be positioned in the inner space formed by the chassis 2b.

The display panel 200 emits light when an image signal, which is an electrical signal, is applied, and can provide an image to a user. The display panel 200 can be classified into a light-receiving panel structure and a self-luminescent panel structure according to a method of generating light. Since the light-receiving panel structure does not emit light by itself, the display device 100 must have a separate backlight unit that generates light and supplies the light to the display panel 200. However, the self-luminous panel structure does not require a separate backlight configuration because the display panel 200 emits itself. The display panel 200 described below is assumed to adopt a self-emission panel structure.

In order to represent each pixel of an image, the display panel 200 may include a plurality of LED modules 210 that themselves generate light. At this time, the plurality of LED modules 210 may be arranged in a predetermined direction. For example, the plurality of LED modules 210 may be arranged in a first direction and in a second direction perpendicular to the first direction. As a result, the display panel 200 can display a two-dimensional image.

When the plurality of LED modules 210 are two-dimensionally arranged, the driving circuit 300 may individually provide image signals to each of the plurality of LED modules 210. To this end, the driving circuit 300 may include a number of driving circuits 300 corresponding to the number of the LED modules 210 arranged in the display panel 200. Each of the plurality of driving circuits 300 may transmit image signals individually to the corresponding LED module 210 to control light generated by each of the plurality of LED modules 210.

Alternatively, the driving circuit 300 may control a plurality of LED modules 210 arranged in two dimensions by rows or columns. If the driving circuit 300 controls the plurality of LED modules 210 on a column basis, the LED modules 210 belonging to the same column can be sequentially activated with a time difference. This will be described in detail with reference to FIG.

The plurality of LED modules 210 can generate light including a visible light, thereby realizing an image formed by a plurality of pixels. To this end, the plurality of LED modules 210 may include a red LED 211, a green LED 212G, and a blue LED 212B.

Referring to FIG. 3A, the LED module 210 includes a red LED 211; Green LED 212G; And a blue LED 212B; A common anode node 213 connecting an anode through which current flows into each LED; As shown in FIG.

The LED module 210 is referred to as a common anode type.

In addition, the LED module 210 may include a plurality of green LEDs 212G. Referring to FIG. 3B, the LED module 210 includes two green LEDs 212G1 and 212G2. Also in this case, the LED module 210 may be provided with a common anode node 213 connecting the red LED 211, the plurality of green LEDs 212G1 and 212G2, and the anode of the blue LED 212B.

As such, the LED module 210 can generate red, green, blue, or a combination thereof, so that the LED module 210 can visually implement each pixel of the image.

On the other hand, the red LED has a different driving voltage from the green or blue LED 212B. Specifically, the red LED 211 emits light when a voltage of about 2.0 V is applied, while the green or blue LED 212G and 212B emits light when a voltage of about 3.5 V is applied. In this case, it is necessary to separate the red LED 211 and the other LEDs 212G and 212B to apply a voltage.

Hereinafter, a display device 2 that supplies different driving voltages to different grounds of LEDs having different driving voltages will be described.

FIG. 4 is a control block diagram of a display device according to an embodiment, FIG. 5 is a control block diagram specifically showing one LED module of the display panel in FIG. 4, and FIG. Figs. 7A and 7B are circuit diagrams for explaining a voltage supply method for an LED module according to various embodiments. Fig.

Referring to FIG. 4, the display device 2 includes a power supply unit 400 for supplying a voltage and a current received from an external power source P; A display panel 200 for supplying driving voltage and driving current from the power supply unit 400 and emitting light; And a driving circuit 300 for controlling a driving voltage and a driving current supplied to the display panel. . ≪ / RTI >

The power supply unit 400 includes a power control unit 410 receiving external power and providing the power to the display panel. And a scan switch (490) connecting a row or column of any one of the plurality of LED modules of the display panel to a power control unit; . ≪ / RTI >

The power control unit 410 may provide driving power for the LED module 210 of the display panel 200 to emit light. In particular, the power control unit 410 may provide different voltages to the plurality of LEDs having different driving voltages, among the LED modules 210. Details of this will be described later.

The scan switch 490 is connected to one of the plurality of LED modules 210 so that the power supplied from the power supply unit 400 is transferred to any one of the plurality of LED modules 210 of the display panel 200. [ A row or a column and a power control unit 410 can be connected.

4 illustrates a case where the scan switch 490 connects one of the plurality of LED modules 210 to the power controller 410. As a result, power can be supplied to the entire plurality of LED modules 210 belonging to any one row.

The scan switch 490 may have a different row or column of a plurality of LED modules 210 connected to the power control unit 410 at predetermined time intervals. For example, the scan switch 490 can sequentially connect the plurality of LED modules 210 to the power control unit 410 at predetermined time intervals. Hereinafter, this operation of the scan switch 490 is referred to as scanning.

4, the scan switch 490 may scan the plurality of LED modules 210 according to a predetermined scanning period. That is, the scan switch 490 can sequentially change the rows of the plurality of LED modules 210 every scanning time. For example, after the scan switch 490 of FIG. 4 connects one row of the plurality of LED modules 210 to the power control unit 410, two rows of the plurality of LED modules 210, The control unit 410 can be connected. In this manner, the scan switch 490 can sequentially scan one to m rows of the plurality of LED modules 210. [

Since the image provided to the user through the display device 2 typically has a frame rate of 15 fps to 30 fps, the scan switch 490 may shorten the scan time shorter than the frame period of the provided image You can carry out the injection with you. Specifically, the scan time of the scan switch 490 may be determined by dividing the frame period by the number of rows of the plurality of LED modules 210 or a value less than the value.

The driving circuit 300 may be connected to a row or column of the plurality of LED modules 210 to control the power supplied to the rows or columns of the LED modules 210. Specifically, when the power supply unit 400 is connected to each row of the plurality of LED modules 210, the driving circuit 300 may be connected to each column of the plurality of the LED modules 210. Conversely, when the power supply unit 200 is connected to the respective rows of the plurality of LED modules 210, the driving circuit 300 may be connected to each row of the plurality of the LED modules 210.

4 illustrates a case where the driving circuit 300 is connected to the respective columns of the plurality of LED modules 210. In FIG. Since the power is sequentially supplied to each of the plurality of LED modules 210 belonging to each row in accordance with the scan of the scan switch 490, the drive circuit 300 includes a plurality of LED modules 210 ) Can control the size of power supplied according to the row in which they are located.

For example, when the scan switch 490 is connected to one row of the plurality of LED modules 210, the first column drive circuit 300-1 supplies power to the LED modules of the first row, You can control the size. At the same time, the second column driving circuit 300-2 can control the size of the power supplied to the LED modules in two rows among the LED modules in one row. In the same manner, the n-th column driving circuit 300-n can control the size of power supplied to the n-th row LED module among the one-row LED modules.

Also, when the scan switch 490 is connected to the m rows of the plurality of LED modules 210, the drive circuit can control the power amount of each of the plurality of LED modules belonging to the m rows similarly to the above-described method.

As a result, the size of the power supplied to each of the plurality of LED modules 210 is controlled, and the display panel 200 can provide one image through light generated by the plurality of LED modules 210.

As described above, the power control unit 410 may provide different voltages to the LEDs 210 having different driving voltages. This will be described with reference to FIG.

5 shows only one LED module 210 in the display panel 200 of FIG. 4 and the LED module 210 is connected to the power control unit 410 by the scan switch 490 . For convenience of explanation, the scan switch 490 is omitted in Fig.

The LED module 210 may include a first LED 212 having a first driving voltage and a second LED 211 having a second driving voltage lower than the first driving voltage. The first LED 212 may include a green LED 212G and a blue LED 212B as an example and the second LED 211 may include a red LED 212R as an example.

Further, as described above, the anode of each of the first LED 212 and the second LED 211 can be connected by the common anode node 213. [ As such, the LED module 210 may be implemented in a common anode manner.

Referring to FIG. 6, in the LED module 210 implemented in the common anode type, each LED may be connected in parallel to the common anode node 213. In this case, conventionally, the same voltage was supplied to each of the plurality of LEDs. Specifically, when the voltage Vcc is supplied through the common anode node 213, the voltage VL is applied to each of the plurality of LEDs equally.

If VL is 3.5 V, which is the drive voltage of the green LED 212G and the blue LED 212B, the red LED 211 can be applied with a voltage higher than the drive voltage 2.0V. As a result, the red LED 211 emits, as heat energy, power corresponding to the voltage supplied beyond the driving voltage. Since the LED module 210 and the driving circuit 300 are vulnerable to heat, if the heat is generated, the performance of the display device 2 may deteriorate.

Accordingly, the first LED 212 and the second LED 211 need to be supplied with different driving voltages. To this end, the voltage applied to the common anode node 213 and the cathodes of the first LEDs 212Ga and 212Ba may be different from the voltage applied to the common anode node 213 and the cathode 211a of the second LEDs.

Referring to FIG. 7A, two supply voltages Vcc1 and Vcc2 may be supplied to the LED module 210 and the driving circuit 300. FIG. The supply voltage Vcc1 forms a loop with the green LED 212G and the blue LED 212B which are the first LED 212 and the first driving circuit 320 connected thereto and the supply voltage Vcc2 forms a loop with the red LED 212G, The LED 211 and the second driving circuit 320 connected thereto can form a loop.

At this time, the common anode potential Vcc1 is supplied to the common anode node 213, and the first driving circuit 320 connected to the cathodes 212Ga and 212Ba of the first LED may be grounded to the ground (0V). In addition, the second driving circuit 320 connected to the cathode 211a of the second LED may be grounded to the potential Vcc1-Vcc2. That is, although the common anode potential is applied to the first LED 212 and the anode 213 of the second LED 211, the potentials of the cathodes 211a, 212Ga, and 212Ba may be differently applied.

As a result, the first LED 212 is supplied with the driving voltage VL1, and the second LED 211 is supplied with the driving voltage VL2 different from VL1. In particular, if the potential applied to the cathode 211a of the second LED is an anode, VL2 may be less than VL1.

The driving voltage applied to the first LED 212 and the second LED 211 is applied to the cathodes 211Ga and 212Ba of the first LED 212 and the cathodes 211a of the second LED 211, When the ground potential is different, there is no unnecessary excessively applied voltage, and heat generated in the LED module 210 or the driving circuit can be reduced.

As described above, if the potentials applied to the cathodes 212Ga and 212Ba of the first LED and the cathodes 211a of the second LED are different, the LED module 210 may be implemented as shown in FIG. 3B. That is, the first LED 212 may include two green LEDs 212G1 and 212G2 and one blue LED 212B.

Referring to FIG. 7B, it is confirmed that the driving voltage VL1 is applied to the first green LED 212G1, the second green LED 212G2, and the blue LED 212B while VL2 is applied to the red LED 211 . This is because the cathode 211a of the second LED 212a and the cathode 212Ga of the first LED 212Ba are different from each other in ground potential.

Specifically, two supply voltages Vcc1 and Vcc2 may be supplied to the LED module 210 and the driving circuit 300. [ The supply voltage Vcc1 forms a loop with the first green LED 212G1 as the first LED 212, the second green LED 212G1 and the blue LED 212B and the first driving circuit 320 connected thereto, Vcc2 may form a loop with the red LED 211, which is the second LED 211, and the second driving circuit 320 connected thereto.

At this time, the common anode potential Vcc1 is supplied to the common anode node 213, and the first driving circuit 320 connected to the cathodes 212Ga and 212Ba of the first LED may be grounded to the ground (0V). In addition, the second driving circuit 320 connected to the cathode 211a of the second LED may be grounded to the potential Vcc1-Vcc2.

As a result, the anode of the first LED 212 and the anode of the second LED 211 are applied with the same common anode potential Vcc1, but the cathode of the first LED 212Ga and the cathode 211a of the second LED Another ground potential can be applied. Specifically, the ground potential applied to the cathode (212Ga. 212Ba) of the first LED is the first ground potential Vcc-VL1, and the ground potential applied to the cathode 211a of the second LED is the second ground potential Vcc1-VL2 .

Accordingly, the first LED 212 is supplied with the driving voltage VL1, and the second LED 211 is supplied with the driving voltage VL2 different from VL1.

If the circuit is configured to have different ground potentials applied to the ground electrodes of the respective LEDs, different driving voltages can be applied to the respective LEDs.

As can be seen in FIGS. 7A and 7B, it may be possible to apply different driving voltages by applying different ground potentials to the cathodes of LEDs having different driving voltages. In order to apply different ground potentials to the cathodes of the plurality of LEDs, the power control unit 410 may be implemented as a switching mode power supply (SMPS). Hereinafter, the power control unit 410 will be described in detail with reference to FIGS. 7A and 7B.

8A and 8B are circuit diagrams of a display device for explaining a power control unit according to various embodiments.

A switching mode power supply may refer to a device that converts a voltage using a switch implemented in a semiconductor device such as a MOSFET. Specifically, when an input voltage is input, the switching mode power supply outputs an output voltage using a switch, and information of an output voltage is used to control the switch.

The switching mode power supply is more efficient and more durable than the linear type power supply, and can be advantageous in size and weight reduction.

The switching mode power supply is divided into a non-isolation type switching mode power supply that does not use a transformer and an isolation type switching mode power supply that uses a transformer.

Hereinafter, an isolation type switching mode power supply, especially a switching mode power supply implemented by a flyback method, is described. However, this is only an embodiment of the switching mode power supply, so that it is not limited thereto.

When the circuit is constructed as shown in FIG. 7A, Vcc1 is supplied to the loop including the first LED 212, and Vcc2 is supplied to the loop including the second LED 211. FIG. Accordingly, the power control unit 410 may include a first power control unit 401 for supplying Vcc1 and a second power control unit 402 for supplying Vcc2.

Referring to FIG. 8A, the power control unit 410 includes a rectifier 411 for rectifying an AC voltage input from the outside to a DC voltage; A first power supply control unit 401 receiving the rectified voltage and outputting a first output voltage; A second power control unit 402 receiving the rectified voltage and outputting a second output voltage; . ≪ / RTI >

The rectifier 411 may be connected to the external power source P to receive power. In addition, the rectifier 411 can rectify the input voltage among the input power to a predetermined DC voltage. At this time, the rectified DC voltage can be determined by the element value of the internal circuit of the rectifier 411.

8A, the rectifier 411 may be implemented as a bridge rectifier. However, the rectifier 411 is not limited to this, and may be variously implemented in a technical idea that outputs a constant direct current according to an AC input.

The first power control unit 401 and the second power control unit 402 may be installed in parallel at the output terminal of the rectifier 411. [

The first power supply control unit 401 includes a first transformer implemented as a 1-1 inductor 440a and a 2-1 inductor 450a; A 1-1 capacitor 420a connected in parallel with the 1-1 inductor 440a; A first switch 430a for controlling a current applied to the 1-1 inductor 440a; A first diode 460a connected to the 2-1 inductor 450a; And a 2-1 capacitor 470a connected in parallel to the 2-1 inductor 450a.

When the first switch 430a is turned on, the voltage rectified by the rectifier 411 is applied to the 1-1 inductor 440a to allow the current to flow. In response to this, a voltage in the opposite direction to that of the 1-1-inductor 440a may be applied to the 2-1 inductor 450a. At this time, since a reverse bias is applied to the first diode 460a connected to the second-1 inductor 450a, the current does not flow.

Accordingly, energy can be charged to the 1-1 capacitor (420a) by the current flowing through the 1-1 inductor (440a), but current does not flow through the 2-1 inductor (450a) 470a are not charged with energy.

On the other hand, when the first switch 430a is turned off, a voltage opposite to that when the first switch 430a is turned on may be applied to the second-1 inductor 450a. As a result, the forward bias is applied to the first diode 460a to charge the second-1 capacitor 470a with energy.

Therefore, finally, the output voltage of Vcc1 can be outputted from the output terminal of the first power control section 401. [

The output Vcc1 may be connected to the first LED 212 of the LED module 210 to supply the first driving voltage VL1 to the first LED 212 as shown in FIG.

The second power source control unit 402 may be implemented by a second transformer implemented by the first and second inductors 440b and 450b in the same manner as the first power source control unit 401. A 1-2 capacitor 420b connected in parallel with the 1-2 inductor 440b; A second switch 430b for controlling the current applied to the 1-2 inductor 440b; A second diode 460b connected to the 2-2 inductor 450b; And a 2-2 capacitor 470b connected in parallel with the 2-2 inductor 450b.

The manner in which the second power supply control unit 402 outputs the voltage may be the same as that of the first power supply control unit 401.

At this time, the second power source control unit 402 may output a voltage Vcc2 that is different from the output voltage of the first power source control unit 401. Referring to FIG. 7A, the output Vcc2 may be connected to the second LED 211 of the LED module 210 to supply the second driving voltage VL2 to the second LED 211. FIG.

In order to output different voltages, the first power control unit 401 and the second power control unit 402 may be grounded at different voltages. Specifically, the ground potential applied to the ground terminal of the output terminal of the first power control unit 401 and the ground potential applied to the ground terminal of the output terminal of the second power control unit 402 may be different.

For example, the first power control unit 401 may be grounded to earth (0V), while the second power control unit 402 may be grounded to Vcc1-Vcc2 higher than the ground. As a result, Vcc1 is supplied to the first loop connected to the first LED 212, and Vcc2 is supplied to the second loop to which the second LED 211 is connected.

In FIG. 8A, the power supply unit outputs a first output voltage for applying the first driving voltage and a second output voltage for applying the second driving voltage, respectively. Alternatively, it may be possible that the power control unit 410 outputs the first output voltage, and converts the first output voltage to output the second output voltage.

Referring to FIG. 8B, the power control unit 410 includes a rectifier 411 for rectifying an AC voltage input from the outside to a DC voltage; A transformer implemented as a first inductor 440 and a second inductor 450; A first capacitor 420 connected in parallel with the first inductor 440; A switch 430 for controlling a current applied to the first inductor 440; A diode 460 connected to the second inductor 450; And a 2-1 capacitor 470a connected in parallel with the second inductor 450; A DC / DC converter 480 for converting the voltage output through the 2-1 capacitor 470a; And a 2-2 capacitor 470b connected in parallel to the DC / DC converter 480; . ≪ / RTI >

When the switch 430 is turned on, the voltage rectified by the rectifier 411 is applied to the first inductor 440 to allow the current to flow. Accordingly, a voltage opposite to that of the first inductor 440 may be applied to the second inductor 450. In this case, since a reverse bias is applied to the diode 460 connected to the second inductor 450, the current does not flow.

Accordingly, although the first capacitor 420 can be charged with energy by the current flowing through the first inductor 440, no current flows through the second inductor 450, so that the second-1 capacitor 470a is charged with energy It does not.

On the other hand, when the switch 430 is turned off, a voltage opposite to that when the switch 430 is turned on may be applied to the second inductor 450. As a result, the forward bias is applied to the diode 460 so that the second-1 capacitor 470a can be charged with energy.

Therefore, the first output voltage of Vcc1 can be output from the second-1 capacitor 470a. As a result, the output Vcc1 may be connected to the first LED 212 of the LED module 210 to supply the first driving voltage VL1 to the first LED 212. [

Meanwhile, the DC / DC converter 480 may convert the output first output voltage Vcc1 to the second output voltage Vcc2. At this time, the DC / DC converter 480 can be variously implemented in a technical idea of outputting the input DC voltage as the converted DC voltage.

The second output voltage thus outputted is charged to the second -2 capacitor 470b and can be stably supplied to the second node. As a result, Vcc2 may be connected to the second LED 211 of the LED module 210 to supply the second driving voltage VL2 to the second LED 211. [

In this manner, in order to output different voltages, the terminal from which the first output voltage is output and the terminal from which the second output voltage is output may be grounded to different voltages. Specifically, the ground potential applied to the ground terminal among the output terminals for outputting the first output voltage and the ground potential applied to the ground terminal among the output terminals for outputting the second output voltage may be different.

For example, when the first output voltage is connected to the first loop, the first loop is grounded to ground (0V), while the second loop to which the second output voltage is connected is grounded to Vcc1-Vcc2, . As a result, Vcc1 is supplied to the first loop connected to the first LED 212, and Vcc2 is supplied to the second loop to which the second LED 211 is connected.

Since the above-described circuit is only an embodiment of the power supply control unit 410, the power supply control unit 410 can be variously implemented in a technical concept of supplying voltages with different ground potentials of LEDs having different driving voltages.

Meanwhile, the power control unit 410 can change the second output voltage supplied to the second loop to find the driving voltage of the second LED 211.

Specifically, the power control unit 410 sets the output voltage for applying the first driving voltage to the second LED 211 as the second output voltage, and confirms the current flowing through the second LED 211 at this time. Then, while the second output voltage is decreased, the change in the current flowing through the second LED 211 is confirmed.

For example, the output voltage Vcc1 for applying the first driving voltage VL1 is outputted from the second output terminal, and the current flowing through the second LED 211 at this time is confirmed. That is, the current when the first driving voltage VL1 is applied to the second LED 211 is confirmed. Then, while the second output voltage is decreased from Vcc1, the change in the current flowing through the second LED 211 is confirmed.

If the voltage applied to the second LED 211 is higher than the second driving voltage, the current flowing through the second LED 211 has a constant value. However, if the voltage applied to the second LED 211 is less than the second driving voltage, the current flowing in the second LED 211 may change.

Therefore, the voltage applied to the second LED 211 can be determined as the second driving voltage at the time when the current flowing through the second LED 211 changes. When the second driving voltage is determined as described above, the second ground potential corresponding to the second driving voltage can be applied to the cathode 211a of the second LED.

As described above, by optimally applying the driving voltage to the LED having a small driving voltage among the plurality of LEDs included in the LED module 210, the power efficiency can be increased.

8 is a flowchart of a display device control method according to an embodiment.

First, power can be supplied from outside. (800) The power supplied from the outside may be DC or AC, and when AC power is supplied, a step of rectifying to DC power may be added.

The common anode node 213 may apply a driving current to the common anode node 213 based on the supplied power source. At this time, the common anode node 213 may supply the driving current to the common anode node 213, And a node connecting the anode of the LED 211.

The driving current applied to the common anode node 213 may be supplied to the first LED 212 as a first driving current i1 to apply the first driving voltage VL1 to the first LED 212. [ , The cathodes (212Ga, 212Ba) of the first LED may be applied with the first ground potential.

As a result, the first driving current i1 may be discharged through the cathodes 212Ga and 212Ba of the first LEDs 830. Through this process, the first LEDs 212 emit light of the corresponding wavelengths . For example, when the first LED 212 is a green LED 212G, the first LED 212 may emit green light by applying a first driving voltage.

In addition, the second driving current i2 of the second LED 211 among the driving currents applied to the common anode node 213 may be applied to the second LED 211. As a result, the second driving voltage VL2 may be applied to the second LED 211. (840) For this, the cathode 211a of the second LED may be applied with the second ground potential.

As a result, the second driving current i2 may be discharged through the cathode 211a of the second LED 850. Finally, the second LED 211 may emit light of a corresponding wavelength. For example, if the second LED 211 is a red LED 211, the second LED 211 may emit red light.

1, 200: display panel
2, 3: Display device
210: LED module
211: Second LED
212: first LED
300: drive circuit
400: Power supply
410:

Claims (18)

An LED module including a first LED having a first driving voltage and a second LED having a second driving voltage smaller than the first driving voltage;
A common anode node connecting an anode of each of the first LED and the second LED; And
A power supply controller for supplying the first and second LEDs with different driving voltages through the common anode node; . The method according to claim 1,
The power control unit includes:
And applies a first driving voltage to the cathode of the common anode node and the cathode of the first LED and applies a second driving voltage to the cathode of the common anode node and the cathode of the second LED. 3. The method of claim 2,
The power control unit includes:
And applies a common anode potential to the common anode node. The method of claim 3,
The power control unit includes:
A first ground potential, which is determined by a difference between the magnitude of the common anode potential and the magnitude of the first driving voltage, is applied to the cathode of the first LED, and the difference between the magnitude of the common anode potential and the magnitude of the second driving voltage To the cathode of the second LED. The method of claim 3,
The power control unit includes:
And applies a potential higher than the cathode of the first LED to the cathode of the second LED. The method according to claim 1,
The power control unit includes:
And determines a driving voltage of the second LED based on a change of a current applied to the second LED in accordance with a change in an output voltage. The method according to claim 6,
The power control unit includes:
And determines a driving voltage of the second LED by checking a current change applied to the second LED while reducing a voltage applied to the second LED from the first driving voltage. 8. The method of claim 7,
The power control unit includes:
And determines a voltage applied to the second LED to be a driving voltage of the second LED at a time when a current applied to the second LED decreases. 3. The method of claim 2,
The power control unit includes:
And outputs a first output voltage for supplying the first driving voltage and a second output voltage for supplying the second driving voltage based on the divided current. 3. The method of claim 2,
The power control unit includes:
A second output voltage for applying the first driving voltage based on the current received from the power supply, and a second output voltage for applying the second driving voltage based on the output first output voltage A display device. The method according to claim 1,
The power control unit includes:
A switch for controlling the flow of the input current received from the power source to output the driving voltage supplied to the LED module; . A display device in which an LED module including a first LED having a first driving voltage and a second LED having a second driving voltage smaller than the first driving voltage is arranged,
Applying a common anode potential to a common anode node connecting an anode of each of the first LED and the second LED;
Applying a first ground potential to a cathode of the first LED so that the first driving voltage is applied to the first LED; And
Applying a second ground potential to the cathode of the second LED so that the second driving voltage is applied to the second LED; And controlling the display device. 13. The method of claim 12,
The step of applying the first ground potential includes:
Determining the first ground potential according to a difference between the magnitude of the common anode potential and the first driving voltage magnitude,
The step of applying the second ground potential includes:
And determining the second ground potential according to a difference between the magnitude of the common anode potential and the second driving voltage magnitude. 13. The method of claim 12,
The step of applying the second ground potential includes:
And applies the second ground potential higher than the first ground potential. 13. The method of claim 12,
Changing the voltage supplied to the second LED to determine the second driving voltage; Further comprising the steps of: 16. The method of claim 15,
Wherein the determining the second driving voltage comprises:
Changing a voltage applied to the second LED;
Determining a current flowing in the second LED according to the changed applied voltage; And
Determining the second drive voltage based on the identified current; And controlling the display device. 17. The method of claim 16,
Wherein the step of varying the voltage applied to the second LED comprises:
Wherein the voltage applied to the second LED is reduced from the first driving voltage. 18. The method of claim 17,
Wherein the determining the second drive voltage based on the identified current comprises:
And determines an applied voltage at a time point when the current applied to the second LED decreases, as the driving voltage of the second LED.

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