Display device

Abstract

A display device is provided. The display device includes: a net power control circuit configured to analyze a screen load from an input image signal to generate a load signal including a load value corresponding to the screen load; and an overcurrent protection circuit configured to set a set current value at a predetermined ratio relative to a global current value corresponding to the load value included in the load signal, and determine whether the display device is powered off based on the set current value.

Description

Technical Field

[0001] Aspects of some example embodiments of the present invention relate to a display device and a driving method thereof. Background Art

[0002] Recently, organic light emitting diode displays have attracted attention as devices for displaying images.

[0003] An organic light emitting diode display uses an organic light emitting diode that generates light by recombining (coupling) electrons and holes to display an image. Since an organic light emitting diode display has a self-emitting characteristic unlike a liquid crystal display device and does not require an additional light source, the organic light emitting diode display can reduce its own thickness and weight. In addition, the organic light emitting diode display has high quality characteristics such as relatively low power consumption, relatively high brightness, and relatively high response speed.

[0004] The organic light emitting diode is driven by using a data voltage according to an image data signal and a power voltage applied to an anode and a cathode. A power line to which the power voltage is applied may be shorted to another wire (such as a data line to which the data voltage is applied). In this case, an overcurrent may occur between the power supply component and the display component, and the organic light emitting diode or the like may be degraded due to the overcurrent, so that the organic light emitting diode display may be damaged.

[0005] In order to prevent the organic light emitting diode display from being damaged due to overcurrent, an overcurrent protection circuit for detecting the current flowing in the power line and shutting down the power supply component may be used. When an overcurrent greater than the set current value of the overcurrent protection circuit occurs, the overcurrent protection circuit shuts down the power supply. However, because the set current value of the overcurrent protection circuit is set to 1.2 times the maximum current that can flow in the display component, the overcurrent protection circuit does not actually work in many cases.

[0006] When the maximum current that can flow in the display component is 30A, the set current value of the overcurrent protection circuit is set to 36A. When a blue image is displayed, a current of about 10A flows in the display component, when a red image is displayed, a current of about 15A flows in the display component, when a green image is displayed, a current of about 18A flows in the display component, and when a white image is displayed, a current of about 30A flows in the display component. Even when a short circuit occurs in a part of the display component, because the current is low except for the case where a white image is displayed therein, the overcurrent protection circuit does not work even when an overcurrent flows because the current flows at 25A or less. In this case, the overcurrent continuously flows in the organic light emitting diode of a part of the display, and thus the organic light emitting diode deteriorates.

[0007] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not constitute the prior art. Summary of the invention

[0008] Aspects of some example embodiments of the present invention relate to a display device and a driving method thereof, for example, to a display device provided with an overcurrent protection circuit and a driving method thereof.

[0009] Aspects of some example embodiments of the present invention include a display device in which an overcurrent protection circuit may adaptively operate with respect to a screen load of the display device, and a driving method thereof.

[0010] According to some example embodiments of the present invention, a display device includes: a net power control circuit that analyzes a screen load from an input image signal to generate a load signal including a load value corresponding to the screen load; and an overcurrent protection circuit that sets a set current value at a predetermined ratio relative to a global current value corresponding to the load value included in the load signal, and determines whether the display device is powered on by using the set current value.

[0011] According to some example embodiments, when the global current value is 1 A or less, the overcurrent protection circuit may set the set current value to a predetermined value instead of setting the set current value by a predetermined ratio with respect to the global current value.

[0012] According to some example embodiments, the load value may increase as the screen load increases until a reference load, and when the screen load is the reference load or greater, the load value may be set to a load value corresponding to the reference load, and the global current value may increase as the screen load increases until a reference load, and when the screen load is the reference load or greater, the global current value may be set to a global current value corresponding to the reference load.

[0013] According to some example embodiments, the display device may further include: a global current modulation circuit that selects a global current value corresponding to a load value included in the load signal, and generates a global current signal including a difference between a global current of a power voltage supplied to the display element and the global current value.

[0014] According to some example embodiments, the display device may further include: a plurality of pixels included in the display component; a power supply that supplies a power voltage for driving the plurality of pixels to the display component; a data driver that applies a data voltage to the plurality of pixels; and a signal controller that receives an input image signal, generates an image data signal by applying a load value and a global current value to the input image signal, and applies the image data signal to the data driver.

[0015] According to some example embodiments, the overcurrent protection circuit may receive a global current of a power voltage supplied to a display component, and when the global current is greater than a set current value, the overcurrent protection circuit may generate a power line error signal, and when the power line error signal is received, the signal controller may control the data driver to display a black image on the display component.

[0016] According to some example embodiments, when a black image is displayed on the display part, the overcurrent protection circuit may receive a global current of the black image, and when the global current of the black image is greater than a black set current value, the overcurrent protection circuit may turn off power.

[0017] According to some example embodiments, the overcurrent protection circuit may set the set current value to one of a first set current value 20% higher than the global current value, a second set current value 25% higher than the global current value, and a third set current value 30% higher than the global current value.

[0018] According to some example embodiments, when a black image is displayed on a display component, the overcurrent protection circuit may receive a global current of the black image, and when the global current of the black image is not greater than a black set current value, the overcurrent protection circuit may increase the set current value to a second set current value or a third set current value.

[0019] According to some example embodiments, when the set current value cannot be increased, the overcurrent protection circuit may shut down the power supply.

[0020] According to some example embodiments of the present invention, a driving method of a display device includes: analyzing a screen load from an input image signal; selecting a load value corresponding to the screen load; selecting a global current value corresponding to the selected load value; and setting a set current value of an overcurrent protection circuit corresponding to the selected load value, wherein whether the display device is powered off can be determined by using the set current value.

[0021] According to some example embodiments, the set current value of the overcurrent protection circuit may be set at a predetermined ratio with respect to the selected global current value.

[0022] According to some example embodiments, the set current value of the overcurrent protection circuit may be set to a value 20% to 30% higher than the selected global current value.

[0023] According to some example embodiments, when the selected global current value is 1A or less, the set current value of the overcurrent protection circuit may be set to a predetermined value instead of setting the set current value by a predetermined ratio relative to the selected global current value.

[0024] According to some example embodiments, the load value may increase as the screen load increases until it reaches a reference load, and when the screen load is equal to or greater than the reference load, the load value may be set to a load value corresponding to the reference load, and the global current value may increase as the screen load increases until it reaches the reference load, and when the screen load is greater than or equal to the reference load, the global current value may be set to a global current value corresponding to the reference load.

[0025] According to some example embodiments, the driving method of the display device may further include: receiving a global current; comparing the global current with a set current value; and displaying a black image when the global current is greater than the set current value.

[0026] According to some example embodiments, the driving method of the display device may further include: receiving a global current of a black image; comparing the global current of the black image with a black set current value; and powering off the display device when the global current of the black image is greater than the black set current value.

[0027] According to some example embodiments, the driving method of the display device may further include: when the global current of the black image is not greater than the black set current value, determining whether the set current value of the overcurrent protection circuit can be increased; and when the set current value of the overcurrent protection circuit can be increased, increasing the set current value of the overcurrent protection circuit and re-driving the display device.

[0028] According to some example embodiments, the set current value of the overcurrent protection circuit can be set to a value 20% higher than the global current value, and the set current value of the overcurrent protection circuit can be increased to a value 25% higher than the global current value or increased to a value 30% higher than the global current value.

[0029] According to some example embodiments, the driving method of the display device may further include: when the set current value of the overcurrent protection circuit cannot be increased, powering off the display device.

[0030] According to some example embodiments, an overcurrent protection circuit may be adaptively operated according to a screen load of a display device and may be operated even at a low screen load to prevent or reduce degradation of an organic light emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A block diagram of a display device according to some example embodiments of the present invention is shown.

[0032] Figure 2 A lookup table for setting a first set current value of an overcurrent protection circuit according to some example embodiments of the present invention is shown.

[0033] Figure 3 A lookup table for setting a second set current value of an overcurrent protection circuit according to some example embodiments of the present invention is shown.

[0034] Figure 4 A lookup table for setting a third set current value of an overcurrent protection circuit according to some example embodiments of the present invention is shown.

[0035] Figure 5 A lookup table for setting a black set current value of an overcurrent protection circuit according to some example embodiments of the present invention is shown.

[0036] Figure 6 A flowchart of a driving method of a display device according to some example embodiments of the present invention is shown.

[0037] Figure 7 Circuit diagrams of pixels according to some example embodiments of the present invention are shown. DETAILED DESCRIPTION

[0038] Aspects of some example embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which aspects of some example embodiments of the invention are shown. As will be appreciated by those skilled in the art, the described embodiments may be modified in various different ways without departing from the spirit or scope of the embodiments according to the present disclosure.

[0039] Furthermore, for the exemplary embodiments of the present invention, constituent elements in the first embodiment are described in detail with reference to relevant drawings using the same reference numerals for the same constituent elements, while only constituent elements different from those related to the first embodiment are described in other embodiments.

[0040] Parts irrelevant to the description will be omitted to clearly describe the present disclosure, and the same reference numerals denote the same elements throughout the specification.

[0041] In this specification, unless explicitly described to the contrary, the word “comprise” and variations such as “comprising”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0042] In the following, reference will be made to Figures 1 to 5 Display devices according to some example embodiments of the present invention are described in more detail.

[0043] Figure 1 A block diagram of a display device according to some example embodiments of the present invention is shown. Figure 2 A lookup table for setting a first set current value of an overcurrent protection circuit according to some example embodiments of the present invention is shown. Figure 3A lookup table for setting a second set current value of an overcurrent protection circuit according to some example embodiments of the present invention is shown. Figure 4 A lookup table for setting a third set current value of an overcurrent protection circuit according to some example embodiments of the present invention is shown. Figure 5 A lookup table for setting a black set current value of an overcurrent protection circuit according to some example embodiments of the present invention is shown.

[0044] Reference Figures 1 to 5 The display device includes a signal controller 100, a net power control (NPC) circuit 110, a global current modulation (GCM) circuit 120, an over current protection (OCP) circuit 130, a gate driver 200, a data driver 300, a power supply 400 and a display component 600.

[0045] Here, the net power control circuit 110 , the global current modulation circuit 120 , and the overcurrent protection circuit 130 are shown to be separately provided from the signal controller 100 , but the net power control circuit 110 , the global current modulation circuit 120 , and the overcurrent protection circuit 130 may be included in the signal controller 100 .

[0046] The signal controller 100 receives an input image signal ImS and a synchronization signal CONT input from an external device or an external source. The input image signal ImS includes brightness information of a plurality of pixels PX. The brightness information has a predetermined number of gray levels. The synchronization signal CONT may include a horizontal synchronization signal, a vertical synchronization signal, and a main clock signal.

[0047] The signal controller 100 generates a first driving control signal CONT1, a second driving control signal CONT2, and an image data signal DAT according to or based on an input image signal ImS and a synchronization signal CONT. The signal controller 100 may classify the input image signal ImS in units of frames according to or based on a vertical synchronization signal, and the signal controller 100 may classify the input image signal ImS in units of gate lines according to or based on a horizontal synchronization signal to generate an image data signal DAT.

[0048] In addition, the signal controller 100 receives a load signal LOAD from the net power control circuit 110 and receives a global current signal GCS from the global current modulation circuit 120. The signal controller 100 may generate an image data signal DAT by applying a load value included in the load signal LOAD to the input image signal ImS. The signal controller 100 may generate an image data signal DAT by applying a global current value included in the global current signal GCS to the input image signal ImS. That is, the signal controller 100 may generate an image data signal DAT by applying a load value and a global current value to the input image signal ImS. The signal controller 100 may adjust the level of the image data signal DAT according to or based on the load value and the global current value.

[0049] The signal controller 100 transmits the first driving control signal CONT1 to the gate driver 200. The signal controller 100 transmits the image data signal DAT and the second driving control signal CONT2 to the data driver 300.

[0050] The display component 600 includes a plurality of pixels PX to display an image. The area in which the plurality of pixels PX are arranged to display an image is referred to as a display area or a screen. The display component 600 includes a plurality of scan lines connected to the plurality of pixels PX and a plurality of data lines connected to the plurality of pixels PX. The plurality of scan lines may extend substantially in the row direction so that they are substantially parallel to each other. The plurality of data lines may extend substantially in the column direction so that they are substantially parallel to each other. The plurality of pixels PX may be arranged in an area where the plurality of scan lines and the plurality of data lines intersect each other. According to the structure of the plurality of pixels PX included in the display component 600, the signal lines included in the display component 600 may be variously changed. For example, the display component 600 may also include a plurality of sensing lines extending in the row direction, a plurality of luminous lines extending in the row direction, a plurality of receiving lines extending in the column direction, and the like. The configuration of the display component 600 is not limited.

[0051] The gate driver 200 is connected to a plurality of gate lines. The gate driver 200 generates a plurality of scan signals G[1] to G[n] according to a first drive control signal CONT1. The plurality of scan signals G[1] to G[n] include a combination of a gate-on voltage and a gate-off voltage. The gate driver 200 may sequentially apply the scan signals G[1] to G[n] having the gate-on voltage to the plurality of gate lines.

[0052] The data driver 300 is connected to a plurality of data lines, samples and holds an image data signal DAT according to a second drive control signal CONT2, and applies a plurality of data signals D[1] to D[m] to the plurality of data lines. The data driver 300 applies data signals D[1] to D[m] having a certain voltage range (e.g., a set or predetermined voltage range) to the data lines in response to scan signals G[1] to G[n] having a gate-on voltage.

[0053] The power supply 400 generates power voltages ELVDD and ELVSS. The power voltages ELVDD and ELVSS include a first power voltage ELVDD and a second power voltage ELVSS. The first power voltage ELVDD and the second power voltage ELVSS are applied to a plurality of pixels PX included in the display component 600. The first power voltage ELVDD and the second power voltage ELVSS are voltages for driving a plurality of pixels PX. The first power voltage ELVDD is a high-level voltage higher than the second power voltage ELVSS, and current can be provided to the anodes of the plurality of pixels PX. The second power voltage ELVSS is a low-level voltage lower than the first power voltage ELVDD, and it can be applied to the cathodes of the plurality of pixels PX.

[0054] The net power control circuit 110 receives an input image signal ImS. The net power control circuit 110 analyzes a screen load from the input image signal ImS. The screen load may be a ratio of a portion in which an image is displayed according to the input image signal ImS relative to the entire screen. The net power control circuit 110 generates a load signal LOAD including a load value corresponding to the screen load. The load value included in the load signal LOAD increases as the screen load increases until a reference load. When the screen load is greater than or equal to the reference load, the load value included in the load signal LOAD is set to a load value corresponding to the reference load.

[0055] like Figures 2 to 4 As shown in , the reference load may be 30%. When the screen load is 1% to 30%, the load value included in the load signal LOAD is set to 1% to 30% corresponding to the screen load. When the screen load is greater than or equal to 30% (reference load), the load value included in the load signal LOAD is set to 30%.

[0056] The net power control circuit 110 transmits the load signal LOAD to the signal controller 100 , the global current modulation circuit 120 , and the overcurrent protection circuit 130 .

[0057] The signal controller 100 may adjust the level of the image data signal DAT according to the load value included in the load signal LOAD. When the screen load is 1%, the signal controller 100 may adjust the level of the image data signal DAT so that the brightness of the maximum grayscale image (e.g., white image) may be 500 nits (nit) and a current of 1A may flow in the display part 600. When the screen load is 30%, the signal controller 100 may adjust the level of the image data signal DAT so that the brightness of the image with the maximum grayscale may be 150 nits and a current of 30A may flow in the display part 600. When the image with the maximum grayscale is displayed, the maximum current that may flow in the display part 600 may be 30A based on the brightness of 150 nits. Even when the screen load is 30% (reference load) or more, since the load value is set to 30%, it may be controlled so that a current greater than the maximum current does not flow in the display part 600.

[0058] That is, the net power control circuit 110 allows the brightness of the image to be adjusted according to or based on the screen load. In addition, the net power control circuit 110 can be used to prevent or reduce the current flowing in the display component 600 exceeding the maximum current under a reference load or greater.

[0059] The global current modulation circuit 120 selects a global current value corresponding to the load value included in the load signal LOAD. Figures 2 to 4 As shown in FIG. 1 , the global current modulation circuit 120 may select global current values ​​of 1A, 10A, 20A, and 30A in response to load values ​​of 1%, 10%, 20%, and 30%.

[0060] The global current modulation circuit 120 receives the global current GC of the power voltages ELVDD and ELVSS supplied to the display part 600 and generates a global current signal GCS including a difference between the global current GC and the global current value and transmits the global current signal GCS to the signal controller 100.

[0061] The signal controller 100 may receive the global current signal GCS and adjust the level of the image data signal DAT so that the difference between the global current GC and the global current value may be reduced.

[0062] That is, the global current modulation circuit 120 may be used to control a constant current so that the global current GC flowing in the display part 600 may become a constant current according to the screen load. Since the net power control circuit 110 is used to allow the level of the image data signal DAT to be adjusted according to the screen load regardless of the global current GC flowing in the display part 600, the brightness of the image changes rapidly due to temperature changes, etc. Since the global current modulation circuit 120 controls the global current GC flowing in the display part 600 to be a constant current according to the screen load, the brightness of the image may not change rapidly.

[0063] The overcurrent protection circuit 130 sets the set current value according to or based on the load value included in the load signal LOAD. The overcurrent protection circuit 130 may set the set current value at a certain ratio (e.g., a set or predetermined ratio) relative to the global current value corresponding to the load value included in the load signal LOAD. The set current value is a reference for determining whether the display device is powered off. The overcurrent protection circuit 130 may include Figures 2 to 5 The lookup table shown in FIG. 1 is used to set the set current value.

[0064] The overcurrent protection circuit 130 can be realized by using Figure 2 The overcurrent protection circuit 130 may set the set current value to be a first set current value 20% higher than the global current value by using a lookup table.

[0065] The overcurrent protection circuit 130 can be realized by using Figure 3 That is, the overcurrent protection circuit 130 may set the set current value to a second set current value that is 25% higher than the global current value.

[0066] The overcurrent protection circuit 130 can be realized by using Figure 4 That is, the overcurrent protection circuit 130 may set the set current value to be the third set current value 30% higher than the global current value.

[0067] However, when the global current value is 1A or less, the overcurrent protection circuit 130 may set the set current value to a certain value (e.g., a set or predetermined value) instead of setting the set current value by a certain ratio (e.g., a set or predetermined ratio) relative to the global current value. That is, when the load value is 1% or less, the overcurrent protection circuit 130 may set the set current value to a certain value (e.g., a set or predetermined value) instead of setting the set current value by a certain ratio (e.g., a set or predetermined ratio) relative to the global current value. Figures 2 to 4 As shown in FIG. 1 , for a global current value of 1A, the first set current value can be set to 2A, the second set current value can be set to 3A, and the third set current value can be set to 4A. Current values ​​20% to 30% higher than the global current value of 1A or less can be 1.2A, 1.25A, 1.3A, etc., and because the difference between these current values ​​and the global current value is relatively small, overcurrent can be determined relatively easily. This problem can be avoided when the set current value is set to a value specified for a global current value of 1A or less.

[0068] The overcurrent protection circuit 130 can calculate the Figures 2 to 4 The load value of the lookup table is in the interval between the global current value and the set current value.

[0069] The overcurrent protection circuit 130 receives the global current GC of the power voltages ELVDD and ELVSS supplied to the display part 600, and when the global current GC is greater than the set current value, performs a process of powering off the display device (i.e., turning off the power supply 400). The power-off of the display device is not determined by only one process of comparing the global current GC with the set current value. The overcurrent protection circuit 130 may further perform a process of comparing the global current GC of a black image with the set current value for a black image, a process of increasing the set current value, etc., to determine the power-off of the display device.

[0070] The overcurrent protection circuit 130 receives the global current GC of the power voltages ELVDD and ELVSS supplied to the display part 600 and generates a power line error signal PL when the global current GC is greater than a set current value. The overcurrent protection circuit 130 transmits the power line error signal PL to the signal controller 100 .

[0071] When the signal controller 100 receives the power line error signal PL, the signal controller 100 allows a black image to be displayed on the display part 600. The signal controller 100 may generate an image data signal DAT for displaying a black image, and control the gate driver 200 and the data driver 300.

[0072] The overcurrent protection circuit 130 can be realized by using Figure 5 The set current value for the black image is set to one of the first black set current value (OCP first black set current value), the second black set current value (OCP second black set current value), and the third black set current value (OCP third black set current value) by using a lookup table. The first black set current value may be 0.1A, the second black set current value may be 0.2A, and the third black set current value may be 0.3A. When the overcurrent protection circuit 130 generates the power line error signal PL for the first time, the set current value for the black image may be set to the first black set current value.

[0073] The overcurrent protection circuit 130 can adjust the detection time for measuring the global current GC. After transmitting the power line error signal PL to the signal controller 100, the overcurrent protection circuit 130 receives the global current GC of the black image after a predetermined time, and compares the global current GC of the black image with the black set current value. This is to measure the global current GC after the black image is displayed on the display part 600 and the global current GC for the black image is generated.

[0074] The overcurrent protection circuit 130 can adjust the change time of the set current value according to the change of the screen load. This is to prevent or reduce the situation where the set current value of the overcurrent protection circuit 130 changes faster than the global current value set according to the changed screen load.

[0075] When a black image is displayed on the display part 600 , the overcurrent protection circuit 130 receives the global current GC of the black image and compares the global current GC of the black image with the first black set current value.

[0076] When the global current GC of the black image is greater than the first black setting current value, the overcurrent protection circuit 130 turns off the power supply 400 to cut off the power of the display device. The overcurrent protection circuit 130 can drive the power supply 400 by normally applying the enable signal EN having the on voltage to the power supply 400. The overcurrent protection circuit 130 can turn off the power supply 400 by applying the enable signal EN having the off voltage to the power supply 400.

[0077] When the global current GC of the black image is not greater than the first black set current value, the overcurrent protection circuit 130 increases the set current value. Figure 2 The overcurrent protection circuit 130 can be configured by using a lookup table to initially set the set current value corresponding to the screen load to the first set current value. Figure 3The overcurrent protection circuit 130 can be used to increase the set current value corresponding to the screen load from the first set current value to the second set current value. Figure 5 The lookup table increases the black setting current value for the black image from the first black setting current value to the second black setting current value.

[0078] After the overcurrent protection circuit 130 increases the set current value from the first set current value to the second set current value, the display device may be driven again. That is, the display device displays an image on the display part 600 according to or based on the input image signal.

[0079] Thereafter, when a global current GC greater than the second set current value is received, a black image is displayed again. The overcurrent protection circuit 130 compares the second black set current value with the global current GC of the black image. When the global current GC of the black image is greater than the second black set current value, the overcurrent protection circuit 130 turns off the power supply 400. When the global current GC of the black image is not greater than the second black set current value, the overcurrent protection circuit 130 turns off the power supply 400. Figure 4 The overcurrent protection circuit 130 can be configured by using a lookup table to increase the set current value corresponding to the screen load from the second set current value to the third set current value. Figure 5 The lookup table increases the black setting current value for the black image from the second black setting current value to the third black setting current value.

[0080] After the overcurrent protection circuit 130 increases the set current value from the second set current value to the third set current value, the display device may be re-driven.

[0081] Thereafter, when a global current GC greater than the third set current value is received, a black image is displayed again. The overcurrent protection circuit 130 compares the third black set current value with the global current GC of the black image. When the global current GC of the black image is greater than the third black set current value, the overcurrent protection circuit 130 turns off the power supply 400. When the global current GC of the black image is not greater than the third black set current value, the overcurrent protection circuit 130 determines whether the set current value can be increased. Since the set current value no longer increases from the third set current value, the overcurrent protection circuit 130 turns off the power supply 400.

[0082] As described above, the overcurrent protection circuit 130 prevents or reduces the situation where a black image is repeatedly displayed on the display part 600 by detecting whether an overcurrent flows in the display device while sequentially increasing the set current value. In addition, by setting the set current value of the overcurrent protection circuit 130 at a certain ratio (e.g., a set or predetermined ratio) relative to the global current value corresponding to the screen load, the overcurrent protection circuit 130 can operate adaptively with respect to the screen load and can detect overcurrent in a low screen load state.

[0083] In the following, reference will be made to Figure 6 As well as the above Figures 1 to 5 A driving method of a display device according to some example embodiments of the present invention will be described in more detail.

[0084] Figure 6 A flowchart of a driving method of a display device according to some example embodiments of the present invention is shown.

[0085] Reference Figure 6 , the display device analyzes a screen load from an input image signal ImS ( ​​S11 ).

[0086] The display device selects a load value corresponding to the screen load (S12). As the screen load increases until the reference load, the load value increases, and when the screen load is greater than or equal to the reference load, the load value may be set to a load value corresponding to the reference load.

[0087] The display device selects a global current value corresponding to the selected load value (S13). As the screen load increases to the reference load, the global current value increases, and when the screen load is greater than or equal to the reference load, the global current value can be set to the global current value corresponding to the reference load.

[0088] The display device sets the set current value of the overcurrent protection circuit 130 corresponding to the selected load value (S14). The display device can be configured by using Figures 2 to 4 The set current value is set by using a lookup table of. The set current value of the overcurrent protection circuit 130 may be set at a certain ratio (e.g., a set or predetermined ratio) relative to the selected global current value. When the selected global current value is 1A or less, the set current value of the overcurrent protection circuit 130 may be set to a certain value (e.g., a set or predetermined value) instead of setting the set current value of the overcurrent protection circuit 130 at a certain ratio (e.g., a set or predetermined ratio) relative to the selected global current value. The set current value is a criterion for determining whether the display device is powered off.

[0089] The display device receives the global current GC of the power voltages ELVDD and ELVSS supplied to the display part 600 ( S15 ).

[0090] The display device compares the global current GC with the set current value ( S16 ).

[0091] When the global current GC is greater than the set current value, the display device displays a black image (S17). When the global current GC is greater than the set current value, the display device may generate a power line error signal PL and display a black image according to the power line error signal PL.

[0092] The display device receives the global current GC of the black image ( S18 ).

[0093] The display device compares the global current GC of the black image with the black setting current value (S19). Figure 5 A lookup table is used to set the black setting current value for a black image.

[0094] When the global current GC of the black image is greater than the black set current value, the display device is powered off ( S22 ).

[0095] When the global current GC of the black image is not greater than the black set current value, the display device determines whether the set current value of the overcurrent protection circuit 130 can be increased (S20). Figure 2 The display device can initially set the set current value of the overcurrent protection circuit 130 by using a lookup table of the overcurrent protection circuit 130. When the process of displaying a black image is repeated because the global current GC is detected to be greater than the set current value, the display device can set the current value of the overcurrent protection circuit 130 from Figure 2 The first set current value of the lookup table increases to Figure 3 The display device may change the setting current value of the overcurrent protection circuit 130 from the second setting current value of the lookup table. Figure 3 The second set current value of the lookup table increases to Figure 4 That is, the set current value of the overcurrent protection circuit 130 can be set to a value 20% higher than the global current value, can be increased to a value 25% higher than the global current value, and can then be increased to a value 30% higher than the global current value.

[0096] When the set current value of the overcurrent protection circuit 130 can be increased, the display device increases the set current value of the overcurrent protection circuit 130, and the display device is re-driven (S21).

[0097] When the set current value of the overcurrent protection circuit 130 cannot be increased, the display device is powered off (S22). After the set current value of the overcurrent protection circuit 130 increases to the third set current value, when a black image is displayed again, the set current value does not increase any more.

[0098] In the following, reference will be made to Figure 7 An example of a pixel PX that may be included in a display device according to some example embodiments of the present invention will be described.

[0099] Figure 7 1 shows a circuit diagram of a pixel according to some example embodiments of the present invention. Figure 1 A pixel PX located in an m-th pixel column and an n-th pixel row among a plurality of pixels PX in a display device is described as an example.

[0100] Reference Figure 7 , the pixel PX includes an organic light emitting diode OLED and a pixel circuit 10 .

[0101] The pixel circuit 10 is configured to control current flowing from the first power voltage ELVDD to the organic light emitting diode OLED. The pixel circuit 10 may include a driving transistor TR1, a switching transistor TR2, a sensing transistor TR3, a light emitting transistor TR4, and a storage capacitor Cst.

[0102] The driving transistor TR1 includes a gate electrode connected to the first node N1, a first electrode to which the first power voltage ELVDD is applied through the light emitting transistor TR4, and a second electrode connected to the second node N2. The driving transistor TR1 is connected between the first power voltage ELVDD and the organic light emitting diode OLED, and controls the amount of current flowing from the first power voltage ELVDD to the organic light emitting diode OLED corresponding to the voltage of the first node N1.

[0103] The switching transistor TR2 includes a gate electrode connected to the scan line SCLn, a first electrode connected to the data line DLm, and a second electrode connected to the first node N1. The switching transistor TR2 is connected between the data line DLm and the driving transistor TR1, and is turned on by a scan signal having a gate-on voltage applied to the scan line SCLn to transfer a data voltage Vdat applied to the data line DLm to the first node N1.

[0104] The sensing transistor TR3 includes a gate electrode connected to the sensing line SSLn, a first electrode connected to the second node N2, and a second electrode connected to the receiving line RLm. The sensing transistor TR3 is connected between the second electrode of the driving transistor TR1 and the receiving line RLm, and the sensing transistor TR3 is turned on by a sensing signal having a gate-on voltage applied to the sensing line SSLn to transmit the current flowing to the organic light emitting diode OLED through the driving transistor TR1 to the receiving line RLm. At the same time, the receiving line RLm can be used as a conductive line for transmitting an initialization voltage to the second node N2. As the initialization voltage is applied to the second node N2 through the receiving line RLm, the anode voltage of the organic light emitting diode OLED can be initialized.

[0105] The light emitting transistor TR4 includes a gate electrode connected to the light emitting line EMLn, a first electrode to which the first power voltage ELVDD is applied, and a second electrode connected to the first electrode of the driving transistor TR1. The light emitting transistor TR4 is turned on by a light emitting signal having a gate-on voltage applied to the light emitting line EMLn to transmit the first power voltage ELVDD to the driving transistor TR1.

[0106] The driving transistor TR1, the switching transistor TR2, and the sensing transistor TR3 may be n-channel field effect transistors, and the light emitting transistor TR4 may be a p-channel field effect transistor. The gate-on voltage for turning on the n-channel field effect transistor is a high-level voltage, and the gate-off voltage for turning off the n-channel field effect transistor is a low-level voltage. The gate-on voltage for turning on the p-channel field effect transistor is a low-level voltage, and the gate-off voltage for turning off the p-channel field effect transistor is a high-level voltage. In some embodiments, at least one of the driving transistor TR1, the switching transistor TR2, and the sensing transistor TR3 may be a p-channel field effect transistor, and the light emitting transistor TR4 may be an n-channel field effect transistor.

[0107] The storage capacitor Cst includes a first electrode connected to the first node N1 and a second electrode connected to the second node N2. The data voltage Vdat is transmitted to the first node N1, and the storage capacitor Cst maintains the voltage of the first node N1.

[0108] The organic light emitting diode OLED includes an anode connected to the second node N2 and a cathode to which the second power voltage ELVSS is applied. The organic light emitting diode OLED can emit light at a brightness corresponding to the current supplied from the pixel circuit 10. The organic light emitting diode OLED can emit light of one of the primary colors or white light. Examples of the primary colors may include three primary colors such as red, green, and blue. Another example of the primary colors may include three primary colors such as yellow, cyan, and magenta.

[0109] Although the present invention has been described in conjunction with embodiments currently considered to be practical, it will be understood that the invention is not limited to the exemplary embodiments, and, on the contrary, the invention is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the attached claims and their equivalents. Therefore, it will be understood by those skilled in the art that various modifications and other equivalent embodiments of the present invention are possible. Therefore, the true technical protection scope of the present invention must be determined based on the technical spirit of the attached claims and their equivalents.

Claims

1. A display device, comprising: a net power control circuit configured to analyze a screen load from an input image signal to generate a load signal including a load value corresponding to the screen load; as well as an overcurrent protection circuit configured to set a set current value at a predetermined ratio relative to a global current value corresponding to the load value included in the load signal, and determine whether the display device is powered off based on the set current value, The overcurrent protection circuit is configured to set the set current value to a predetermined value in response to the global current value being less than a threshold value, rather than setting the set current value to the predetermined ratio relative to the global current value.

2. The display device according to claim 1, wherein: The overcurrent protection circuit is configured to set the set current value to the predetermined value in response to the global current value being 1 A or less, rather than setting the set current value by the predetermined ratio with respect to the global current value.

3. The display device according to claim 1, wherein: the load value increases as the screen load increases up to a reference load, and in response to the screen load being the reference load or more, the load value is set to a load value corresponding to the reference load; and The global current value increases as the screen load increases up to the reference load, and in response to the screen load being the reference load or more, the global current value is set to a global current value corresponding to the reference load.

4. The display device according to any one of claims 1 to 3, further comprising: A global current modulation circuit is configured to select the global current value corresponding to the load value included in the load signal and generate a global current signal including a difference between a global current of a power voltage supplied to a display element and the global current value.

5. The display device according to claim 4, further comprising: A plurality of pixels are located in the display component; a power supply configured to supply a power voltage for driving the plurality of pixels to the display element; a data driver configured to apply data voltages to the plurality of pixels; as well as A signal controller is configured to receive the input image signal, generate an image data signal by applying the load value and the global current value to the input image signal, and apply the image data signal to the data driver.

6. The display device according to claim 5, wherein: the overcurrent protection circuit being configured to receive the global current of the power voltage supplied to the display component and to generate a power line error signal in response to the global current being greater than the set current value; and The signal controller is configured to control the data driver to display a black image on the display part in response to receiving the power line error signal.

7. The display device according to claim 6, wherein: The overcurrent protection circuit is configured to receive a global current of the black image in response to the black image being displayed on the display section, and to turn off the power supply in response to the global current of the black image being greater than a black set current value.

8. The display device according to claim 6, wherein: The overcurrent protection circuit is configured to set the set current value to one of a first set current value 20% higher than the global current value, a second set current value 25% higher than the global current value, and a third set current value 30% higher than the global current value.

9. The display device according to claim 8, wherein: In response to the black image being displayed on the display component, the overcurrent protection circuit receives the global current of the black image, and in response to the global current of the black image being not greater than the black set current value, the overcurrent protection circuit increases the set current value to the second set current value or the third set current value.

10. The display device according to claim 9, wherein: The overcurrent protection circuit is configured to shut down the power supply in response to the set current value failing to increase.

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