LED display driving circuit and LED display device including same

Abstract

The invention discloses an LED display driving circuit and an LED display device comprising the same. The LED display driving circuit comprises a channel driving circuit which supplies channel current to each channel line connected with a plurality of LEDs according to a pulse width modulation (PWM) control signal; a scan driving circuit including a plurality of scan switches selectively driving each scan line to cause the plurality of LEDs to emit light and a plurality of pre-charge switches turned on when the scan switches are turned off and supplying pre-charge voltages to the scan lines; a short circuit detection unit for detecting whether the plurality of LEDs are short-circuited and detecting the degree of short circuit; the data controller is used for turning off the pre-charging switch of the target scanning line when the scanning switch of the target scanning line connected with the short-circuit LED is turned off and keeping the target scanning line in a floating state when the short-circuit LED is detected; and a brightness compensation unit that compensates the brightness of the normal LED connected to the target channel line to which the short-circuited LED is connected according to the degree of short-circuiting of the short-circuited LED during driving of the scanning lines other than the target scanning line.

Description

Technical Field

[0001] This disclosure relates to display devices, and more specifically, to a light-emitting diode (LED) display. Background Technology

[0002] With the advancement of information technology, various display devices capable of visualizing information are being developed. Display devices that have been developed or are under development include liquid crystal displays (LCDs), organic light-emitting diode (OLEDs), and plasma display panels (PDPs). These devices are being advanced to appropriately display high-resolution images.

[0003] However, while the aforementioned display devices have the advantage of high resolution, they also have the disadvantage of being difficult to scale up. For example, the size range of large OLED display devices developed to date is 80 inches (approximately 2 meters) to 100 inches (approximately 2.5 meters), which is not suitable for manufacturing large display devices with a width exceeding 10 meters.

[0004] As a solution to this scaling problem, light-emitting diode (LED) display devices have recently received increasing attention. In LED display device technology, a desired number of modular LED pixels can be arranged to form a large panel. Alternatively, in LED display device technology, a desired number of unit panels comprising multiple LED pixels can be arranged to form a large panel structure. Thus, in LED display device technology, large-scale display devices can be easily realized by increasing the number of LED pixels as needed and arranging the increased number of LED pixels.

[0005] LED display devices offer the advantage of not only increasing size but also diversifying panel sizes. LED display technology allows for the adjustment of horizontal and vertical dimensions in various ways based on the appropriate arrangement of LED pixels.

[0006] In the aforementioned LED display device, when the LED of a specific pixel is short-circuited, there is a problem that the brightness of all normal LEDs connected to the same channel line as the short-circuited LED may become brighter (bright line) or darker (dark line) due to the short-circuited LED, resulting in a decrease in image quality.

[0007] To solve this problem, one could consider detecting and repairing the short-circuited LED or replacing the short-circuited LED with a normal one, but this approach is costly and time-consuming. Summary of the Invention

[0008] This disclosure aims to provide an LED display driver circuit capable of detecting not only fully short-circuited light-emitting diodes (LEDs) but also partially short-circuited LEDs, and an LED display device including the same.

[0009] This disclosure also aims to provide an LED display driver circuit capable of reducing line defects caused by short-circuited LEDs, and an LED display device including the same.

[0010] This disclosure also aims to provide an LED display driver circuit capable of compensating the brightness of a normal LED connected to the same channel line as the short-circuited LED according to the degree of short circuit of the short-circuited LED, and an LED display device including the same.

[0011] According to one aspect of this disclosure, an LED display driving circuit is provided, comprising: a channel driving circuit configured to supply channel current to each of a plurality of channel lines to which a plurality of LEDs are connected, according to a pulse width modulation (PWM) control signal; a scan driving circuit including a plurality of scan switches configured to selectively drive each scan line to cause the plurality of LEDs to emit light, and a plurality of precharge switches to be turned on and supply a precharge voltage to the scan line when the scan switches are turned off; a short circuit detection unit configured to detect whether the plurality of LEDs are short-circuited and the degree of short circuit; a data controller, which, when a short-circuited LED is detected, turns off the precharge switch of the target scan line when the scan switch of the target scan line to which the short-circuited LED is connected is turned off, and maintains the target scan line in a floating state; and a brightness compensation unit configured to compensate the brightness of normal LEDs connected to the target channel line to which the short-circuited LED is connected, according to the degree of short circuit of the short-circuited LED, during the driving of scan lines other than the target scan line.

[0012] According to another aspect of this disclosure, an LED display device is provided, comprising: a display panel including a plurality of LEDs; and an LED display driving circuit configured to supply channel current to the plurality of LEDs to cause the plurality of LEDs to emit light, wherein the LED display driving circuit includes: a channel driving circuit configured to supply channel current through each channel line according to a PWM control signal; a scan driving circuit including a plurality of scan switches configured to selectively drive each scan line to cause the plurality of LEDs to emit light and a plurality of precharge switches turned on when the scan switches are turned off and supplying a precharge voltage to the scan lines; a short circuit detection unit configured to detect whether the plurality of LEDs are short-circuited and the degree of short circuit; a data controller, which, when a short-circuited LED is detected, turns off the precharge switch of the target scan line when the scan switch of the target scan line to which the short-circuited LED is connected is turned off, and maintains the target scan line in a floating state; and a brightness compensation unit configured to compensate the brightness of normal LEDs connected to the target channel line to which the short-circuited LED is connected according to the degree of short circuit of the short-circuited LED during the driving of scan lines other than the target scan line. Attached Figure Description

[0013] The accompanying drawings are included to provide a further understanding of this disclosure and are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the disclosure and, together with the description, serve to illustrate the principles of the disclosure. In the drawings:

[0014] Figure 1 This is a diagram illustrating the configuration of a light-emitting diode (LED) display device according to one embodiment of the present disclosure;

[0015] Figure 2 This is a schematic diagram showing the configuration of an LED display driving circuit according to one embodiment of the present disclosure;

[0016] Figure 3 This is a diagram showing the waveform of a scanning signal in an LED display device according to one embodiment of the present disclosure;

[0017] Figure 4 It is shown Figure 3 The timing diagram shown is for the operation timing of some components of a normal LED display device.

[0018] Figure 5A and Figure 5B This is a diagram showing the line defect phenomenon caused by a short-circuited LED;

[0019] Figure 6A This is a diagram showing the phenomenon (bright line) where all LEDs connected to the first channel line become brighter when the level of the pre-charge voltage is higher than the level of the first channel voltage to which the short-circuited LED is connected;

[0020] Figure 6B This is a diagram showing the phenomenon (dark lines) where all LEDs connected to the first channel line become dimmer when the level of the pre-charge voltage is lower than the level of the first channel voltage to which the short-circuited LED is connected;

[0021] Figure 7 This is a timing diagram showing the operating timing of some components of an LED display device, including a short-circuited LED;

[0022] Figure 8 This is a schematic block diagram illustrating the configuration of a short-circuit detection unit according to one embodiment of the present disclosure;

[0023] Figure 9 This is a diagram illustrating an example of detecting the degree of short circuit and determining the amount of brightness compensation based on the degree of short circuit according to one embodiment of the present disclosure;

[0024] Figure 10 This is a schematic block diagram illustrating the configuration of a brightness compensation unit according to one embodiment of the present disclosure;

[0025] Figure 11This is a schematic block diagram showing the configuration of a brightness compensation amount generation unit according to one embodiment of the present disclosure;

[0026] Figure 12 This is a diagram illustrating an example of a short-circuit simulation circuit according to one embodiment of the present disclosure;

[0027] Figure 13 This is a schematic block diagram illustrating the configuration of an error detection unit according to one embodiment of the present disclosure;

[0028] Figure 14 It is a graph showing the waveform of the counter enable signal and the brightness compensation amount according to the degree of short circuit;

[0029] Figure 15 This is a flowchart illustrating a method by which a brightness compensation amount generation unit generates brightness compensation amounts according to various short-circuit degrees according to an embodiment of the present disclosure;

[0030] Figure 16A and Figure 16B This is a diagram showing the point defect phenomenon (dark spot) where a short-circuited LED does not emit light. Detailed Implementation

[0031] The advantages and features of this disclosure and its implementation methods will be illustrated by the following exemplary embodiments described with reference to the accompanying drawings. However, this disclosure may be embodied in various forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. Furthermore, this disclosure is limited only by the scope of the claims.

[0032] Throughout this disclosure, the same reference numerals denote substantially the same elements. In the following description, detailed descriptions of relevant known functions or configurations will be omitted where it is determined that such descriptions would unnecessarily obscure the essence of this disclosure. Furthermore, the names of elements used in the following description are illustrative and may differ from the names of the actual products corresponding to those elements.

[0033] In the context of the use of “comprising,” “having,” and “including” as described in this disclosure, an additional part may be added. Unless otherwise stated, singular terms may include plural forms.

[0034] When interpreting components, even if not explicitly described, the components are interpreted as including a range of error.

[0035] It will be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Therefore, without departing from the scope of this disclosure, the first element referred to below may be called the second element.

[0036] The term "at least one" should be understood to include any and all combinations of one or more of the related listed items. For example, "at least one of the first, second, and third items" means each of the first, second, and third items, as well as all combinations of two or more items derived from the first, second, and third items.

[0037] Those skilled in the art will fully understand that the features of the various exemplary embodiments of this disclosure may be partially or wholly linked or combined with each other, and may interoperate or be combined and technically driven with each other in various ways. The exemplary embodiments of this disclosure may be implemented independently of each other, or may be implemented together in an interdependent relationship.

[0038] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0039] Figure 1 This is a diagram illustrating the configuration of a light-emitting diode (LED) display device according to one embodiment of the present disclosure.

[0040] like Figure 1 As shown, an LED display device 100 according to one embodiment of the present disclosure includes a display panel 110 and an LED display driving circuit 120.

[0041] The display panel 110 includes a plurality of pixels P. The plurality of pixels P can be in a first direction (e.g., Figure 1 (horizontal direction) and second direction (e.g., Figure 1 The LEDs are arranged in a matrix in the vertical direction of the display panel. At least one LED can be provided in each pixel P, and the brightness of pixel P can be determined according to the brightness of the LEDs. That is, the display panel 110 can be an LED display panel.

[0042] Each pixel P can include multiple sub-pixels. For example, each pixel P can include three sub-pixels. Each pixel P can include a red sub-pixel representing red, a green sub-pixel representing green, and a blue sub-pixel representing blue. An LED can be set in each sub-pixel.

[0043] Multiple channel lines CL1 to CLm and multiple scan lines SL1 to SLn are provided in the display panel 110. Each sub-pixel can be set in the area where the channel lines and scan lines intersect. That is, the LED set in each sub-pixel can be electrically connected to one of the channel lines CL1 to CLm and one of the scan lines SL1 to SLn.

[0044] Each of the channel lines CL1 to CLm can connect to one side of each sub-pixel in the second direction, and each of the scan lines SL1 to SLn can connect to the other side of each sub-pixel in the first direction. For example, the anode of an LED disposed in a sub-pixel can be electrically connected to the channel lines CL1 to CLm, and the cathode of the LED can be electrically connected to the scan lines SL1 to SLn. Figure 1 The example shown is also referred to as a common cathode structure because the cathodes of the LEDs are connected together, but this implementation is not limited to this structure.

[0045] LED display driver circuit 120 supplies channel current to a plurality of LEDs included in display panel 110, so that the plurality of LEDs emit light. In one embodiment, the LEDs can be driven in a pulse width modulation (PWM) manner, and the LED display driver circuit 120 can perform PWM control on each pixel P according to image data DATA received from the outside.

[0046] The image data DATA may include the grayscale value of each pixel P, and the LED display driver circuit 120 may receive the image data DATA from the outside according to the clock CLK and may obtain the grayscale value of each pixel P from the image data DATA.

[0047] The LED display driver circuit 120 can determine the PWM control time of the LEDs set in each sub-pixel based on the grayscale value, and can perform PWM control on each LED. As described above, when driving LEDs in PWM mode, the brightness of the LEDs can be determined based on the ratio of the on-time to the PWM control time. Therefore, the LED display driver circuit 120 can control the brightness of the LEDs by controlling the on-time in the PWM control time.

[0048] Specifically, the brightness of the LEDs located in each sub-pixel can be determined based on the amount of channel current supplied through the channel lines CL1 to CLm connected to the LEDs. When the LEDs are turned on by the channel current, a positive voltage is generated in the LEDs. When the product of the positive voltage and the channel current accumulates during the on-time in the PWM control time, the amount of drive power supplied to the LEDs can be obtained, and the brightness of the LEDs can be determined based on the amount of drive power.

[0049] In the following text, reference will be made to Figure 2 The LED display driver circuit according to this disclosure is described in more detail.

[0050] Figure 2 This is a schematic diagram illustrating the configuration of an LED display driving circuit according to one embodiment of the present disclosure. For ease of description, in Figure 2 In the middle, the display panel 110 is shown as including three scan lines SL1 to SL3, three channel lines CL1 to CL3 and nine LEDs.

[0051] like Figure 2 As shown, the LED display driving circuit 120 may include a scanning driving circuit 122, a channel driving circuit 124, a data controller 126, and a brightness compensation unit 130.

[0052] Scan drive circuit 122 is connected to multiple scan lines SL1 to SL3 to drive scan lines SL1 to SL3 according to scan signals SCAN_1 to SCAN_3 supplied from data controller 126. For this purpose, as follows... Figure 2 As shown, the scan drive circuit 122 includes multiple scan switches SW1 to SW3.

[0053] Because in Figure 2 The display panel 110 is shown as including only three scan lines SL1 to SL3, so the scan drive circuit 122 is shown as including only three scan switches SW1 to SW3. However, when the display panel 110 includes n scan lines SL1 to SLn, the scan drive circuit 122 may include n scan switches SW1 to SWn.

[0054] Multiple scan switches SW1 to SW3 are connected to scan lines SL1 to SL3. The multiple scan switches SW1 to SW3 are selectively turned on or off according to scan signals SCAN_1 to SCAN_3 supplied from the data controller 126. As the corresponding scan switch among the scan switches SW1 to SW3 is turned on according to the supply of scan signals SCAN_1 to SCAN_3, each of the scan lines SL1 to SL3 can be connected to a low-voltage portion (e.g., the level of ground GND) in the LED display device 100.

[0055] As scan switches SW1 to SW3 are selectively turned on or off according to scan signals SCAN_1 to SCAN_3, the scan line SL1, SL2, or SL3 among the multiple scan lines SL1 to SL3 that are supplied with channel current is determined.

[0056] In the above embodiments, it is described that scan switches SW1 to SW3 are formed within the LED display driving circuit 120. However, in other embodiments, scan switches SW1 to SW3 may be formed in the display panel 110 or on a separate substrate.

[0057] Figure 3This is a diagram showing the waveform of a scanning signal in an LED display device according to one embodiment of the present disclosure.

[0058] Reference Figure 1 and Figure 3 A frame consists of N segments (N is a natural number), and for each segment, scan signals SCAN_1 to SCAN_n can be supplied sequentially to scan switches SW1 to SWn. Here, a frame can be the individual images that make up the video, and a segment can be a unit of one cycle of scanning operation.

[0059] According to scan signals SCAN_1 to SCAN_n, the first scan line SL1 to the nth scan line SLn can be driven sequentially. However, according to the implementation, the scan operation is not performed sequentially from the first scan line SL1 to the nth scan line SLn. For example, the order of the scan operation can be determined by the printed circuit board (PCB) wiring.

[0060] In one implementation, when each sub-pixel is controlled by PWM once within a frame, the grayscale value can be directly converted into a PWM control value, and each sub-pixel can be controlled according to the PWM control value. On the other hand, when a frame is divided into N segments, the grayscale value can be divided and assigned to the N segments, and the PWM control value can be determined based on the grayscale value assigned to each segment. In this case, each sub-pixel can be controlled based on the PWM control value converted from the grayscale value assigned to each segment.

[0061] Refer to Figure 2 The scanning drive circuit 122 according to this disclosure may further include a pre-charge voltage supply unit 210 and pre-charge switches PSW1 to PSW3. Since the display panel 110 is in Figure 2 The display panel 110 is shown as including only three scan lines SL1 to SL3, so the scan drive circuit 122 is shown as including only three precharge switches PSW1 to PSW3. However, when the display panel 110 includes n scan lines SL1 to SLn, the scan drive circuit 122 may include n precharge switches PSW1 to PSWn.

[0062] To prevent ghosting of LED emission light connected to scan lines SL1 to SL3 where the scanning operation has ended, the precharge voltage supply unit 210 supplies a precharge voltage Vprecharge to the scan lines SL1 to SL3 where the scanning operation has ended. Precharging refers to the operation of charging capacitors C1 to C3 connected to the scan lines SL1 to SL3 where the scanning operation has ended before the scanning operation of other scan lines SL3 to SLn begins. Precharging can be performed between the end time of the scanning operation and the start time of the next scanning operation.

[0063] As the pre-charge voltage supply unit 210 pre-charges capacitors C1 to C3, the voltage across capacitors C1 to C3 increases. Therefore, the LEDs connected to capacitors C1 to C3 remain in a reverse-biased state, preventing current from flowing to them. Consequently, the LEDs connected to capacitors C1 to C3 of scan lines SL1 to SL3, where the scan operation has ended, do not emit light.

[0064] In this case, capacitors C1 to C3 can be parasitic capacitors of the LED. Capacitors C1 to C3 can also be capacitors that form electrostatic capacitance within the LED display device 100 according to the operation of the LED display driver circuit 120 or the display panel 110. Capacitors C1 to C3 can be virtual capacitors, rather than physical capacitors.

[0065] Capacitors C1 to C3 form a capacitance between each of the LEDs and scan switches SW1 to SW3. Although the display panel 110... Figure 2 The display panel 110 is shown as including three capacitors C1 to C3, but when the display panel 110 includes n scan lines SL1 to SLn, the display panel 110 may include n capacitors C1 to Cn.

[0066] Precharge switches PSW1 to PSW3 are selectively turned on or off by precharge control signals PCS_1 to PCS_3 generated by data controller 126, thereby supplying precharge voltage to each of scan lines SL1 to SL3. When precharge switches PSW1 to PSW3 are turned on by precharge control signals PCS_1 to PCS_3, scan lines SL1 to SL3 are connected to precharge voltage supply unit 210, and the capacitors C1 to C3 of scan lines SL1 to SL3 are charged using the precharge voltage.

[0067] In the following text, reference will be made to Figure 4 Briefly describe the scanning and pre-charge operations performed in the first scan line SL1.

[0068] Figure 4 It is shown Figure 3 The timing diagram shows the operation timing of each component of the LED display device.

[0069] like Figure 4 As shown, the first scan switch SW1 is turned on in response to the first scan signal SCAN_1, thus connecting the first scan line SL1 to ground. In this case, the first precharge switch PSW1 is turned off according to the first precharge control signal PCS_1. Therefore, the voltage of the first capacitor C1 set on the first scan line SL1 can decrease from the time when the first scan switch SW1 is turned on, and can be maintained at a minimum value until the time when the first scan switch SW1 is turned off.

[0070] Subsequently, the first scan switch SW1 is turned off according to the first scan signal SCAN_1, so that the first scan line SL1 is maintained at the scan off level, and after a predetermined time has elapsed, the second scan switch SW2 is turned on in response to the second scan signal SCAN_2. In this case, the second scan switch SW2 is turned on after a predetermined time has elapsed from the time point when the first scan switch SW1 is turned off, to prevent the LEDs connected to the first scan line SL1 and the second scan line SL2 from emitting light simultaneously due to the overlapping operation of the first scan line SL1 and the second scan line SL2.

[0071] Furthermore, when the first scan switch SW1 is turned off, the first precharge switch PSW1 is turned on via the first precharge control signal PCS_1, so that the first capacitor C1 connected to the first scan line SL1 is charged using the precharge voltage. As the charge on the first capacitor C1 increases, the voltage of the first capacitor C1 can increase. The voltage of the first capacitor C1 can reach its maximum value before the second scan switch SW2 is turned on, and can remain at its maximum value until the first scan line SL1 is driven again.

[0072] That is, the first capacitor C1 can be pre-charged between the time when the first scan switch SW1 is turned off and the time when the second scan switch SW2 is turned on. Since the voltage of the first capacitor C1 is maintained at its maximum value as the first capacitor C1 is pre-charged, the LED connected to the first capacitor C1 can be maintained in a reverse bias state, thus preventing ghosting.

[0073] Subsequently, the second scan switch SW2 is turned on according to the second scan signal SCAN_2, thus connecting the second scan line SL2 to ground. In this case, the second precharge switch PSW2 is turned off according to the second precharge control signal PCS_2. Therefore, the voltage of the second capacitor C2 set on the second scan line SL2 can decrease from the time when the second scan switch SW2 is turned on, and remain at its minimum value until the time when the second scan switch SW2 is turned off.

[0074] Subsequently, the second scan switch SW2 is turned off according to the second scan signal SCAN_2 so that the second scan line SL2 is maintained at the scan off level, and after a predetermined time has elapsed, the third scan switch SW3 is turned on according to the third scan signal SCAN_3.

[0075] Furthermore, when the second scan switch SW2 is turned off, the second pre-charge switch PSW2 is turned on via the second pre-charge control signal PCS_2, so that the second capacitor C2 connected to the second scan line SL2 is charged using the pre-charge voltage. As the charge on the second capacitor C2 increases, the voltage of the second capacitor C2 can increase. The voltage of the second capacitor C2 can reach its maximum value before the third scan switch SW3 is turned on, and can remain at its maximum value until the second scan line SL2 is driven again.

[0076] That is, the second capacitor C2 can be precharged between the time when the second scan switch SW2 is turned off and the time when the third scan switch SW3 is turned on, and since the voltage of the second capacitor C2 is maintained at its maximum value as the second capacitor C2 is precharged, the LED connected to the second capacitor C2 can be maintained in a reverse bias state, thus preventing the phantom phenomenon.

[0077] Subsequently, the third scan switch SW3 is turned on according to the third scan signal SCAN_3, thus connecting the third scan line SL3 to ground. In this case, the third precharge switch PSW3 is turned off according to the third precharge control signal PCS_3. Therefore, the voltage of the third capacitor C3 set on the third scan line SL3 can decrease from the time when the third scan switch SW3 is turned on, and can be maintained at a minimum value until the time when the third scan switch SW3 is turned off.

[0078] Subsequently, the third scan switch SW3 is turned off according to the third scan signal SCAN_3, so that the third scan line SL3 is maintained at the scan off level, and after a predetermined time has elapsed, the fourth scan switch SW4 is turned on according to the fourth scan signal SCAN_4.

[0079] Furthermore, when the third scan switch SW3 is turned off, the third pre-charge switch PSW3 is turned on via the third pre-charge control signal PCS_3, so that the third capacitor C3 connected to the third scan line SL3 is charged using the pre-charge voltage. As the charge of the third capacitor C3 increases, the voltage of the third capacitor C3 can increase. The voltage of the third capacitor C3 can reach its maximum value before the fourth scan switch SW4 is turned on, and can be maintained at the maximum value until the third scan line SL3 is driven again.

[0080] That is, the third capacitor C3 can be precharged between the time when the third scan switch SW3 is turned off and the time when the fourth scan switch SW4 is turned on, and since the voltage of the third capacitor C3 is maintained at its maximum value as the third capacitor C3 is precharged, the LED connected to the third capacitor C3 can be maintained in a reverse bias state, thus preventing the phantom phenomenon.

[0081] Refer to Figure 2The channel driving circuit 124 is connected to multiple channel lines CL1 to CLm and supplies channel current to the sub-pixels connected to the channel lines CL1 to CLm through the channel lines CL1 to CLm. In this case, the channel driving circuit 124 can control the amount of channel current supplied to the LEDs connected to the channel lines CL1 to CLm according to the PWM control signals PWM_1 to PWM_m supplied from the data controller 126.

[0082] For this purpose, the channel drive circuit 124 may include channel current sources 220_1 to 220_m and PWM switches 230_1 to 230_m for channel lines CL1 to CLm.

[0083] exist Figure 2 For ease of description, only the three channel lines CL1 to CL3 included in the display panel 110 are shown. Therefore, the channel driving circuit 124 is shown as including the first channel current source 220_1 to the third channel current source 220_3 and the first PWM switch 230_1 to the third PWM switch 230_3. However, when the display panel 110 includes m channel lines CL1 to CLm, the channel driving circuit 124 may include m channel current sources 220_1 to 220_m and m PWM switches 230_1 to 230_m.

[0084] The operations of the first channel current source 220_1 to the third channel current source 220_3 are identical, and the operations of the first PWM switch 230_1 to the third PWM switch 230_3 are also identical. Therefore, in the following text, only the operations of the first channel current source 220_1 and the first PWM switch 230_1 will be described.

[0085] The first channel current source 220_1 can generate channel current using an externally supplied LED driving voltage VLED. The channel current generated by the first channel current source 220_1 can be supplied to the LED connected to the first channel line CL1 via the first channel line CL1. The first channel current source 220_1 can be connected in series between the LED driving voltage VLED application line and the first PWM switch 230_1.

[0086] The first PWM switch 230_1 selectively turns on or off according to the first PWM control signal PWM_1 received from the data controller 126, thereby adjusting the duration of channel current supplied through the first channel line CL1. The amount of channel current supplied through the first channel line CL1 can be determined based on the on-time of the first PWM switch 230_1. Therefore, the brightness of the LED connected to the first channel line CL1 can be determined.

[0087] like Figure 4As shown, the first PWM control signal PWM_1 may include an on segment and an off segment (corresponding to segments other than the on segment). The first PWM switch 230_1 is turned on in the on segment of the first PWM control signal PWM_1 to supply the channel current supplied from the first channel current source 220_1 to the first channel line CL1, and is turned off in the off segment of the first PWM control signal PWM_1 to block the supply of the channel current supplied from the first channel current source 220_1 to the first channel line CL1.

[0088] The first PWM switch 230_1 can be connected in series between the LED and the first channel current source 220_1.

[0089] In one implementation, such as Figure 4 As shown, during the driving of each of the scan lines SL1 to SL3, when the first PWM control signal PWM_1 is turned on and the channel current is supplied to the first channel line CL1, the first channel voltage V_CH1 applied to the first channel line CL1 can increase from the level of the reference voltage Voff, which is higher than the level of ground GND. When the first PWM control signal PWM_1 is turned off and the supply of channel current stops, the first channel voltage V_CH1 can decrease again to the level of the reference voltage Voff.

[0090] In this disclosure, the first channel voltage V_CH1 applied to the first channel line CL1 during the driving of each of the scan lines SL1 to SL3 is maintained at a reference voltage Voff level higher than ground GND because the time taken for the first channel voltage V_CH1 of the first channel line CL1 to increase to its maximum value according to the supply of channel current is reduced.

[0091] Therefore, such as Figure 2 As shown, the channel drive circuit 124 according to this disclosure may further include a first reference voltage generation circuit 240_1 for generating a reference voltage Voff and a first reference voltage application switch 250_1 for selectively applying the reference voltage Voff to the first channel line CL1. In this case, the first reference voltage application switch 250_1 may be selectively turned on or off according to a first reference voltage application signal RVS_1 sent from the data controller 126.

[0092] exist Figure 2For ease of description, only the three channel lines CL1 to CL3 included in the display panel 110 are shown. Therefore, the channel driving circuit 124 is shown as including the first reference voltage generation circuit 240_1 to the third reference voltage generation circuit 240_3 and the first reference voltage application switch 250_1 to the third reference voltage application switch 250_3. However, when the display panel 110 includes m channel lines CL1 to CLm, the channel driving circuit 124 may include m reference voltage generation circuits 240_1 to 240_m and m reference voltage application switches 250_1 to 250_m.

[0093] The data controller 126 can generate scan signals SCAN_1 to SCAN_n, PWM control signals PWM_1 to PWM_m, precharge control signals PCS_1 to PCS_n, and reference voltage application signals RVS_1 to RVS_m. The data controller 126 applies the scan signals SCAN_1 to SCAN_n and the precharge control signals PCS_1 to PCS_n to the scan drive circuit 122, and applies the PWM control signals PWM_1 to PWM_m and the reference voltage application signals RVS_1 to RVS_m to the channel drive circuit 124.

[0094] In one implementation, the data controller 126 can adjust the length of the on-state segment of each of the PWM control signals PWM_1 to PWM_m according to the internal clock GCLK. The data controller 126 can adjust the length of the on-state segment of each of the PWM control signals PWM_1 to PWM_m to correspond to one unit of grayscale value for one cycle of the internal clock GCLK. For example, when the grayscale value is 1, the length of the on-state segment of each of the PWM control signals PWM_1 to PWM_m can be equal to one cycle of the internal clock GCLK.

[0095] In the LED display device 100 described above, when any one of the plurality of LEDs included in the display panel 110 is short-circuited, such as Figure 5A and Figure 5B As shown, a line defect may occur where all LEDs connected to the corresponding channel line become brighter or dimmer.

[0096] Specifically, such as Figure 6AAs shown, when the first LED L11 connected to the first channel line CL1 and the first scan line SL1 is short-circuited, and the level of the pre-charge voltage is higher than the first channel voltage V_CH1 of the first channel line CL1, when the second LED L12 to the nth LED L1n connected to the first channel line CL1 emits light, the pre-charge voltage supplied through the first scan line SL1 is also supplied to the second LED L12 to the nth LED L1n through the short-circuited first LED L11, resulting in all LEDs connected to the first channel line CL1 becoming brighter (bright line).

[0097] As another example, such as Figure 6B As shown, when the first LED L11 connected to the first channel line CL1 and the first scan line SL1 is short-circuited, and the level of the pre-charge voltage is lower than the first channel voltage V_CH1 of the first channel line CL1, when the second LED L12 to the nth LED L1n connected to the first channel line CL1 emits light, the channel current supplied through the first channel line CL1 should discharge through the short-circuited first LED L11, resulting in all LEDs connected to the first channel line CL1 becoming dimmer (dark lines).

[0098] Therefore, as Figure 2 As shown, the LED display driving circuit 120 according to this disclosure may further include short-circuit detection units 260_1 to 260_3 to detect the image quality degradation caused by the short-circuited LED as described above.

[0099] exist Figure 2 In the diagram, short-circuit detection units 260_1 to 260_3 are shown as being configured for channel lines CL1 to CL3, but this is merely an example. A single short-circuit detection unit may be connected to all channel lines CL1 to CL3 to detect a short-circuit LED in each of the channel lines CL1 to CL3. According to this implementation, the short-circuit detection unit may be included in the channel drive circuit 124, or it may be implemented as a component separate from the channel drive circuit 124.

[0100] Short-circuit detection units 260_1 to 260_3 detect whether each LED in the display panel 110 is short-circuited and the degree of short circuit. That is, short-circuit detection units 260_1 to 260_3 can detect not only whether each of the multiple LEDs is short-circuited, but also the degree of short circuit of the short-circuited LED. For example, short-circuit detection units 260_1 to 260_3 can determine whether the short-circuited LED is a completely short-circuited LED or a partially short-circuited LED. Here, when the non-short-circuit state is a state of infinite resistance, the completely short-circuit state can be a state of 0 resistance, and the partially short-circuit state can be a state of resistance greater than 0 and less than infinity.

[0101] Furthermore, short-circuit detection units 260_1 to 260_3 can detect whether each LED is short-circuited and the degree of short circuit during the driving period of a specific scan line, in the section before the PWM control signal is supplied to the channel line. That is, short-circuit detection units 260_1 to 260_3 can use the reference voltage Voff supplied to each channel line to detect whether each LED is short-circuited and the degree of short circuit during the section before the PWM control signal is supplied to the channel line.

[0102] Specifically, short-circuit detection units 260_1 to 260_3 can use a reference voltage Voff to determine whether each LED is short-circuited and the degree of short circuit. The reference voltage Voff is the channel voltage supplied by each of the channel lines CL1 to CL3 to the LED connected to the scan lines SL1 to SL3 selected by the scan drive circuit 122.

[0103] In one embodiment, when the scan drive circuit 122 selects scan lines SL1 to SL3, the short circuit detection units 260_1 to 260_3 can detect whether each LED is short-circuited and the degree of short circuit by comparing the channel voltage of each of the channel lines CL1 to CL3 with multiple reference voltages of different voltage levels.

[0104] In the following text, reference will be made to Figure 8 and Figure 9 The configuration of a short-circuit detection unit according to one embodiment of the present disclosure is described in more detail.

[0105] Figure 8 This is a schematic block diagram illustrating the configuration of a short-circuit detection unit according to one embodiment of the present disclosure. Figure 9 This is a diagram illustrating an example of detecting the degree of short circuit and determining the amount of brightness compensation based on the degree of short circuit according to one embodiment of the present disclosure.

[0106] Since the configuration and operation of short-circuit detection units 260_1 to 260_3 are the same, the following description will mainly focus on the configuration and operation of one short-circuit detection unit, which will be represented by the label 260.

[0107] like Figure 8 As shown, the short-circuit detection unit 260 includes a reference voltage generation unit 262, a first multiplexer 264, a comparator 266, and a determination unit 268.

[0108] The reference voltage generation unit 262 generates multiple reference voltages VREF_1 to VREF_n to detect whether each LED is short-circuited and the degree of short circuit. In this case, the reference voltages VREF_1 to VREF_n can have different voltage levels. For example, as Figure 9As shown, the reference voltage generation unit 262 can generate eight reference voltages VREF_1 to VREF_8 with different voltage levels. In this case, the voltage level of the first reference voltage VREF1 can be a value higher than the voltage level of the nth reference voltage VREF_n.

[0109] In one embodiment, the reference voltage generation unit 262 may be a low-dropout (LDO) regulator that uses an externally input reference voltage to generate multiple reference voltages VREF_1 to VREF_n with different voltage levels.

[0110] The first multiplexer 264 can select any one of the multiple reference voltages VREF_1 to VREF_n generated by the reference voltage generation unit 262 according to the selection signal S input from the outside, and can output the selected reference voltage to the comparator 266. In one embodiment, when a frame includes multiple segments (such as...) Figure 3 As shown), the reference voltage can be mapped to each segment in a one-to-one correspondence. According to this implementation, as... Figure 9 As shown, during the driving of each of segments SF1 to SF8, the first multiplexer 264 selects a reference voltage from a plurality of reference voltages VREF_1 to VREF_8 that maps to each of segments SF1 to SF8 and outputs the selected reference voltage to comparator 266. In this case, the data controller 126 determines which of the plurality of segments SF1 to SF8 is currently operating, generates a selection signal S corresponding to the currently operating segment, and outputs the selection signal S to the first multiplexer 264.

[0111] Furthermore, in the above embodiment, the first reference voltage VREF_1 to the nth reference voltage VREF_n can be selected sequentially for segments SF1 to SFN. However, in another embodiment, the first reference voltage VREF_1 to the nth reference voltage VREF_n can be randomly selected for segments SF1 to SFN, regardless of the order of the segments SF1 to SFN. In this case, the first reference voltage VREF_1 to the nth reference voltage VREF_n are selected for segments SF1 to SFN without repetition.

[0112] exist Figure 9 In the example shown, by determining that the second segment SF2 is currently operating, the data controller 126 generates a selection signal S for selecting the second reference voltage VREF_2 corresponding to the second segment SF2 and outputs the selection signal S to the first multiplexer 264. The first multiplexer 264, in response to the selection signal S input from the data controller 126, outputs the second reference voltage VREF_2 corresponding to the second segment SF2 to the comparator 266.

[0113] Comparator 266 compares one of the reference voltages VREF_1 to VREF_n output from the first multiplexer 264 with the channel voltage V_CH (e.g., reference voltage Voff) and outputs the comparison result to determination unit 268.

[0114] The determining unit 268 detects whether the LED is short-circuited and the degree of short circuit based on the comparison result of the comparator 266. In one embodiment, such as Figure 9 In the example shown, when the channel voltage V_CH is lower than the first reference voltage VREF_1 with the highest voltage level and higher than the nth reference voltage VREF_n with the lowest voltage level, the determining unit 268 determines that the corresponding LED is partially short-circuited; when the channel voltage V_CH is lower than or equal to the nth reference voltage VREF_n, the corresponding LED is determined to be completely short-circuited.

[0115] As an example, in Figure 9 In the example shown, when the channel voltage V_CH is lower than the first reference voltage VREF_1 and higher than the eighth reference voltage VREF_8, the determination unit 268 determines that the corresponding LED is partially short-circuited; when the channel voltage V_CH is lower than or equal to the eighth reference voltage VREF_8, the corresponding LED is determined to be completely short-circuited.

[0116] In this example, determining unit 268 determines that the short circuit severity of an LED with a channel voltage V_CH between the first reference voltage VREF_1 and the second reference voltage VREF_2 is less severe than that of an LED with a channel voltage V_CH between the second reference voltage VREF_2 and the third reference voltage VREF_3. Additionally, determining unit 268 determines that the short circuit severity of an LED with a channel voltage V_CH between the second reference voltage VREF_2 and the third reference voltage VREF_3 is less severe than that of an LED with a channel voltage V_CH between the third reference voltage VREF_3 and the fourth reference voltage VREF_4. Similarly, determining unit 268 determines that the short circuit severity of an LED with a channel voltage V_CH between the sixth reference voltage VREF_6 and the seventh reference voltage VREF_7 is less severe than that of an LED with a channel voltage V_CH between the seventh reference voltage VREF_7 and the eighth reference voltage VREF_8.

[0117] The determination unit 268 provides the brightness compensation unit 130 with the determination results of whether a short circuit exists and the degree of short circuit.

[0118] Furthermore, when a short-circuited LED is detected, the determining unit 268 can generate and store the position information of the short-circuited LED based on the information of the scan lines SL1 to SL3 and the channel lines CL1 to CL3 to which the short-circuited LED is connected. As an example, when the short-circuited LED is connected to the first scan line SL1 and the first channel line CL1, the short-circuit detection unit 260 can generate and store the position information of the short-circuited LED as (1,1). In the following text, for ease of description, the scan line to which the short-circuited LED is connected is referred to as the target scan line, and the channel line to which the short-circuited LED is connected is referred to as the target channel line.

[0119] The short-circuit detection unit 260 can provide the data controller 126 with the position information of the short-circuited LED. For ease of description, it is assumed below that the first LED L11 connected to the first scan line SL1 and the first channel line CL1 is short-circuited. In this example, the first scan line SL1 becomes the target scan line, and the first channel line CL1 becomes the target channel line.

[0120] As described above, according to this disclosure, since the determining unit 268 can determine not only whether the LED is short-circuited, but also the degree of short circuit of the LED, the brightness compensation amount can be adjusted according to the degree of short circuit of the LED, thereby preventing under-compensation or over-compensation of the brightness of normal LEDs.

[0121] Refer to Figure 2 Based on the position information of the short-circuit LED L11 sent from short-circuit detection units 260_1 to 260_3, when the driving of the target scan line SL1 connected to the short-circuit LED L11 ends, the data controller 126 can float the target scan line SL1. For this purpose, as... Figure 7 As shown, when the light emission period of the short-circuit LED L11 ends and the scan switch of the target scan line SL1 to which the short-circuit LED L11 is connected is turned off again, the data controller 126 generates a precharge control signal PCS_1 to turn off the first precharge switch PSW1 connected to the target scan line SL1 and applies the precharge control signal PCS_1 to the first precharge switch PSW1.

[0122] Therefore, as Figure 7 As shown, after the first scan switch SW1 connected to the target scan line SL1 is turned off, the first pre-charge switch PSW1 connected to the target scan line SL1 is also turned off, causing the target scan line SL1 to enter a floating state. Therefore, the target scan line SL1 to which the short-circuit LED L11 is connected remains in a floating state until the target scan line SL1 is driven again. In the floating state, the voltage of the target scan line SL1 can be maintained at a level lower than the scan off voltage (the voltage when the first scan switch SW1 connected to the target scan line SL1 is turned off) and higher than the ground voltage (the voltage when the scan switch is turned on).

[0123] In addition, the data controller 126 can determine which segment among the multiple segments SF1 to SFN is currently operating in order to detect whether a short circuit exists and the degree of the short circuit. It can generate a selection signal S corresponding to the segment currently operating and output the selection signal S to the short circuit detection units 260_1 to 260_3.

[0124] Furthermore, based on the position information of the short-circuited LED L11 sent from short-circuit detection units 260_1 to 260_3, when the short-circuited LED L11 emits light, the data controller 126 can block the supply of channel current through the target channel line CL1 connected to the short-circuited LED L11. Therefore, as... Figure 7 As shown, when the short-circuited LED L11 emits light, the data controller 126 generates a first PWM control signal PWM_1 to turn off the first PWM switch 230_1 of the target channel line CL1 to which the short-circuited LED L11 is connected. This blocks the supply of channel current to the short-circuited LED L11.

[0125] In one embodiment, when the short-circuited LED L11 emits light, the data controller 126 can also block the supply of the reference voltage Voff to the target channel line CL1 connected to the short-circuited LED L11. According to this embodiment, when the short-circuited LED L11 emits light, such as Figure 7 As shown, the first channel voltage V_CH1 of the target channel line CL1 to which the short-circuited LED L11 is connected can be maintained at the level of ground GND. To this end, the data controller 126 can generate a first reference voltage application signal RVS_1 when the short-circuited LED L11 emits light, for turning off the first reference voltage application switch 250_1 of the target channel line CL1 to which the short-circuited LED L11 is connected, and can send the first reference voltage application signal RVS_1 to the first reference voltage application switch 250_1.

[0126] As described above, according to this disclosure, when the short-circuit detection units 260_1 to 260_3 detect a short-circuit LED L11, the data controller 126 can turn off the first pre-charge switch PSW1 connected to the target scan line SL1 connected to the short-circuit LED L11 to maintain the target scan line SL1 in a floating state. At the same time, it can turn off the first PWM switch 230_1 connected to the target channel line CL1 connected to the short-circuit LED L11 to block the supply of channel current through the target channel line CL1, thereby preventing all LEDs connected to the target channel line CL1 from becoming brighter or dimmer due to the short-circuit LED L11.

[0127] Furthermore, as mentioned above, such as Figure 2As shown, the LED display driving circuit 120 according to one embodiment of the present disclosure may further include a brightness compensation unit 130 to maximize the effect of reducing image quality degradation as described above.

[0128] Specifically, when LED L11 is short-circuited, the data controller 126 floats the target scan line SL1, such as... Figure 7 As shown, during the driving of other normal LEDs L12 and L13 connected to the target channel line CL1, the time it takes for the first channel voltage V_CH1 to increase from the reference voltage to its maximum value can be shortened compared to when the LEDs are not short-circuited.

[0129] Therefore, when any of the scan lines SL2 and SL3 other than the target scan line SL1 is selected, the brightness compensation unit 130 can compensate for the brightness of the normal LED connected to the target channel line CL1. In one embodiment, the brightness compensation unit 130 can use different brightness compensation amounts to compensate for the brightness of the normal LED according to the degree of short circuit of the LED determined by the short circuit detection units 260_1 to 260_3.

[0130] According to the above embodiment, the brightness compensation unit 130 can be used to compensate the brightness of normal LEDs L12 and L13 according to the short-circuit degree of short-circuit LED L11 during the light-emitting period of normal LEDs L12 and L13 connected to the target channel line CL1.

[0131] In the following text, reference will be made to Figure 10 The configuration of a brightness compensation unit according to one embodiment of the present disclosure will be described in more detail.

[0132] Figure 10 This is a schematic block diagram illustrating the configuration of a brightness compensation unit according to one embodiment of the present disclosure. Figure 10 As shown, a brightness compensation unit 130 according to one embodiment of the present disclosure includes a register 132, a second multiplexer 134, and a brightness compensation amount selection unit 136.

[0133] In register 132, each brightness compensation value is mapped and stored according to the short circuit degree of the LED. That is, when the short circuit detection units 260_1 to 260_n use n reference voltages VREF_1 to VREF_n to detect whether the LED is short-circuited and the degree of short circuit, the degree of short circuit can be determined in n levels, and n brightness compensation values ​​LCD1 to LCDn can be stored in register 132 according to the short circuit degree divided into n levels.

[0134] As an example, such as Figure 9In the example shown, when the short circuit detection units 260_1 to 260_n use eight reference voltages VREF_1 to VREF_8 to detect whether the LED is short-circuited and the degree of short circuit, the degree of short circuit can be determined in eight levels, and eight brightness compensation values ​​LCD1 to LCD8 can be stored in register 132 according to the eight levels of short circuit.

[0135] In one embodiment, the brightness compensation amount based on the degree of short circuit of the LED can be automatically generated when the LED display device 100 is operating in the brightness compensation amount generation mode. In this case, the brightness compensation amount generation mode can be executed at the turn-on or turn-off time of the LED display device 100.

[0136] Therefore, such as Figure 10 As shown, the LED display device 100 according to this disclosure may further include a brightness compensation amount generation unit 140. The brightness compensation amount generation unit 140 is activated when the LED display device 100 is operating in the brightness compensation amount generation mode, generates a brightness compensation amount based on the short circuit degree of the LED, and stores the generated brightness compensation amount in the register 132.

[0137] In the following text, reference will be made to Figure 11 The brightness compensation amount generation unit 140 according to this disclosure will be described in more detail.

[0138] Figure 11 This is a schematic block diagram illustrating the configuration of a brightness compensation amount generation unit according to one embodiment of the present disclosure. Figure 11 As shown, a brightness compensation amount generation unit 140 according to one embodiment of the present disclosure includes a short-circuit simulation circuit 142, an error detection unit 144, and a compensation amount generation control unit 146.

[0139] A short-circuit simulation circuit 142 simulates short circuits for each LED. The short-circuit simulation circuit 142 is connected between channel lines CL1 to CLm and scan lines SL1 to SLn. More specifically, the short-circuit simulation circuit 142 can be connected in parallel to each LED in each region where one of the channel lines CL1 to CLm intersects with one of the scan lines SL1 to SLn, and can simulate the short-circuit state of each LED. The short-circuit simulation circuit 142 may include multiple resistor adjustment circuits to simulate short circuits for each LED.

[0140] By using multiple resistor adjustment circuits, the short-circuit simulation circuit 142 can simulate the short-circuit degree of each LED by adjusting the resistance between channel lines CL1 to CLm and scan lines SL1 to SLn. In the following text, reference will be made to... Figure 12 The configuration of the short-circuit simulation circuit 142 according to one embodiment of the present disclosure is described in more detail.

[0141] Figure 12 This is a diagram illustrating an example of a short-circuit simulation circuit according to one embodiment of the present disclosure. Figure 12 As shown, a short-circuit simulation circuit 142 according to one embodiment of the present disclosure may include a plurality of resistor adjustment circuits RCC1 to RCCn connected in parallel with each other. In one embodiment, the number of resistor adjustment circuits RCC1 to RCCn may be adjusted according to the degree of short circuit. As an example, when the degree of short circuit is divided into eight levels, the short-circuit simulation circuit 142 may include eight resistor adjustment circuits RCC1 to RCC8.

[0142] Furthermore, the resistance adjustment circuits RCC1 to RCCn may each include switches SW1 to SWn and resistors R1 to Rn connected in series with the switches SW1 to SWn, and all resistors R1 to Rn may be designed to have the same resistance value.

[0143] Each of the switches SW1 to SWn can be selectively turned on or off according to the control signals LV_SW1 to LV_SWn input from the compensation amount generation control unit 146. In this case, the control signals LV_SW1 to LV_SWn may include a first control signal LV_SW1 that turns on only one switch, a second control signal LV_SW2 that turns on only two switches, and an nth control signal LV_SWn that turns on all n switches.

[0144] When only one switch is turned on according to the first control signal LV_SW1, only one resistor element is connected between the channel lines CL1 to CLm and the scan lines SL1 to SLn. Therefore, the resistance between the channel lines CL1 to CLm and the scan lines SL1 to SLn is the highest, thus simulating the first-level short-circuit state with the weakest short-circuit degree.

[0145] Similarly, when only two switches are turned on according to the second control signal LV_SW2, only two resistor elements are connected in parallel between each other between channel lines CL1 to CLm and scan lines SL1 to SLn. Therefore, the resistance between channel lines CL1 to CLm and scan lines SL1 to SLn is the second highest, thereby simulating the second-level short-circuit state with the second weak short-circuit degree.

[0146] When all n switches are turned on according to the nth control signal LV_SWn, all n resistor elements R1 to Rn are connected in parallel between the channel lines CL1 to CLm and the scan lines SL1 to SLn. Therefore, the resistance between the channel lines CL1 to CLm and the scan lines SL1 to SLn is minimized, thereby simulating the nth level short circuit state with the strongest short circuit degree.

[0147] exist Figure 12In the diagram, the short-circuit simulation circuit 142 is shown as being implemented using multiple switches SW1 to SWn and multiple resistive elements R1 to Rn, but this is merely an example. The short-circuit simulation circuit 142 can also be implemented using multiple transistors. According to this implementation, different levels of short-circuit states can be simulated by adjusting the number of transistors turned on according to control signals LV_SW1 to LV_SWn.

[0148] Refer to Figure 11 The error detection unit 144 compares the short-circuit channel voltage V_Short of the channel line connected to the LED that has been simulated for a short circuit by the short-circuit simulation circuit 142 with the normal channel voltage V_Normal of the normal channel that has not been simulated for a short circuit, and outputs a counter enable signal COUNTER_EN with either a first level or a second level to the compensation amount generation control unit 146 based on the comparison result.

[0149] In one implementation, when the short-circuit channel voltage V_Short differs from the normal channel voltage V_Normal, the error detection unit 144 can output a counter enable signal COUNTER_EN with a first level (e.g., high level), and when the short-circuit channel voltage V_Short is the same as the normal channel voltage V_Normal, it can output a counter enable signal COUNTER_EN with a second level (e.g., low level). Referring below... Figure 13 The configuration of the error detection unit 144 according to this disclosure is described in more detail.

[0150] Figure 13 This is a schematic block diagram illustrating the configuration of an error detection unit according to one embodiment of the present disclosure. Figure 13 As shown, an error detection unit 144 according to one embodiment of the present disclosure may include a first integrator 1310, a second integrator 1320 and a comparator 1330.

[0151] The first integrator 1310 integrates the short-circuit channel voltage V_Short (the voltage applied to the corresponding channel line when the PWM reference signal PWM_REF is supplied to the channel line to which the LED simulating the short circuit is connected), and outputs the first integration result to the first input terminal I1 of the comparator 1330.

[0152] The second integrator 1320 integrates the normal channel voltage V_Normal (the voltage applied to the normal channel line) and outputs the second integration result to the second input terminal I2 of the comparator 1330.

[0153] Comparator 1330 compares the first integral result input through the first input terminal I1 with the second integral result input through the second input terminal I2, and generates a counter enable signal COUNTER_EN with a first level or a second level based on the comparison result. Comparator 1330 outputs the counter enable signal COUNTER_EN to the compensation amount generation control unit 146.

[0154] In one embodiment, when the first integration result differs from the second integration result, the comparator 1330 outputs a counter enable signal COUNTER_EN with a first level (e.g., high level) to the compensation quantity generation control unit 146. Conversely, when the first integration result is the same as the second integration result, the comparator 1330 outputs a counter enable signal COUNTER_EN with a second level (e.g., low level) to the compensation quantity generation control unit 146.

[0155] The compensation amount generation control unit 146 controls the short-circuit simulation circuit 142 to adjust the short-circuit degree. In addition, the compensation amount generation control unit 146 generates a brightness compensation amount based on the short-circuit degree and stores the brightness compensation amount in the register 132.

[0156] Specifically, the compensation amount generation control unit 146 generates a first control signal LV_SW1 to simulate the weakest level of short circuit, and supplies the first control signal LV_SW1 to the short circuit simulation circuit 142 to allow only one resistor to be connected between the channel lines CL1 to CLm and the scan lines SL1 to SLn, thereby allowing the resistance between the channel lines CL1 to CLm and the scan lines SL1 to SLn to have the highest value.

[0157] Additionally, the compensation amount generation control unit 146 generates the nth control signal LV_SWn to simulate the strongest level of short circuit, and supplies the nth control signal LV_SWn to the short circuit simulation circuit 142 to allow all n resistors to be connected in parallel between the channel lines CL1 to CLm and the scan lines SL1 to SLn, thereby allowing the resistance between the channel lines CL1 to CLm and the scan lines SL1 to SLn to have the lowest value.

[0158] The compensation amount generation control unit 146 determines the brightness compensation amount according to each short circuit degree by increasing or decreasing the brightness compensation amount according to the level of the counter enable signal COUNTER_EN input from the comparator 1330.

[0159] Specifically, such as Figure 14As shown, when the comparator 1330 outputs a counter enable signal COUNTER_EN with a first level (high level), the compensation amount generation control unit 146 determines the brightness compensation amount according to each short circuit degree by gradually increasing the brightness compensation amount until the comparator 1330 inputs a counter enable signal COUNTER_EN with a second level (low level).

[0160] That is, the compensation amount generation control unit 146 supplies a brightness compensation amount to the data controller 126, and the data controller 126 adds the unit brightness compensation amount output from the compensation amount generation control unit 146 to the on-state segment of the PWM reference signal PWM_REF to be supplied to the channel drive circuit of the channel line to which the LED connected for short-circuit simulation is connected, to generate a final PWM reference signal PWM_REF', and supplies the generated final PWM reference signal PWM_REF' to the channel drive circuit of the corresponding channel line. Therefore, when a normal LED connected to the corresponding channel line emits light, the short-circuit channel voltage V_Short can increase until it becomes equal to the normal channel voltage V_Normal.

[0161] The compensation amount generation control unit 146 determines the brightness compensation amount when the brightness compensation amount is the second level (low level) counter enable signal COUNTER_EN input from comparator 1330 as the brightness compensation amount corresponding to the corresponding short circuit degree, and stores the determined brightness compensation amount in register 132 by mapping the determined brightness compensation amount to the corresponding short circuit degree.

[0162] Therefore, from Figure 14 The waveform diagram shows that when the short circuit level is low (e.g., LV1), the brightness compensation is small because the counter enable signal COUNTER_EN is maintained at the first level for a short time. As the short circuit level increases to higher levels (e.g., LV8), the brightness compensation increases because the counter enable signal COUNTER_EN is maintained at the first level for a longer time. In other words, it can be seen that the required brightness compensation is small when the short circuit level is low, but large when the short circuit level is high.

[0163] In the following text, reference will be made to Figure 15 The present invention describes a method for generating a brightness compensation amount based on various short-circuit conditions using a brightness compensation amount generation unit.

[0164] Figure 15 This is a flowchart illustrating a method by which a brightness compensation amount generation unit generates brightness compensation amounts according to various short-circuit degrees, based on an embodiment of the present disclosure.

[0165] When the brightness compensation amount generation mode is started, the brightness compensation amount generation unit 140 generates control signals LV_SW1 to LV_SWn for turning on at least one of the switches SW1 to SWn included in the short-circuit simulation circuit 142, and supplies the signals LV_SW1 to LV_SWn to the short-circuit simulation circuit 142 (S1500).

[0166] According to the control signals LV_SW1 to LV_SWn, the number of switches corresponding to the control signals LV_SW1 to LV_SWn are turned on, and the resistor element connected to the corresponding switch is connected between the scan line and the channel line of the LED that simulates the short circuit (S1510).

[0167] Subsequently, the brightness compensation amount generation unit 140 compares the short-circuit channel voltage of the channel line to which the LED simulating the short circuit is connected with the normal channel voltage of the normal channel line to which the normal LED is connected (S1520), and when the short-circuit channel voltage is different from the normal channel voltage as a result of the comparison, it outputs a counter enable signal COUNTER_EN with a first level (high level) (S1530).

[0168] When the counter enable signal COUNTER_EN with a first level (high level) is output, the brightness compensation amount generation unit 140 adds a predetermined unit brightness compensation amount to the PWM reference signal PWM_REF supplied to the channel line connected to the LED simulating a short circuit, generating a final PWM reference signal PWM_REF', and inputs the final PWM reference signal PWM_REF' to the channel drive circuit connected to the LED simulating a short circuit (S1550). Thereafter, the brightness compensation amount generation unit 140 repeats operations S1520 to S1550 until the short-circuit channel voltage becomes equal to the normal channel voltage.

[0169] Furthermore, in operation S1520, when the short-circuit channel voltage is the same as the normal channel voltage, the brightness compensation amount generation unit 140 outputs a counter enable signal COUNTER_EN with a second level (low level) (S1540). Thereafter, the brightness compensation amount generation unit 140 stores the brightness compensation amount when the counter enable signal COUNTER_EN with the second level (low level) is output as the brightness compensation amount corresponding to the degree of short circuit caused by the corresponding control signal (S1560).

[0170] Next, the brightness compensation amount generation unit 140 determines whether all switches SW1 to SWn included in the short-circuit simulation circuit 142 are turned on (S1570), and when it is determined that all switches SW1 to SWn are turned on, the brightness compensation amount generation mode ends (S1580). Furthermore, when all switches SW1 to SWn included in the short-circuit simulation circuit 142 are not turned on, it determines that another switch is turned on (S1590), and then the process returns to operation S1500 to repeat the subsequent operation.

[0171] Refer to Figure 10 The second multiplexer 134 outputs one of the n brightness compensation values ​​LCD1 to LCDn stored in the register 132 to the data controller 126 according to the selection signal S input from the brightness compensation amount selection unit 136.

[0172] The brightness compensation amount selection unit 136 generates a selection signal S for selecting a brightness compensation amount from among n brightness compensation amounts LCD1 to LCDn that corresponds to the short circuit degree input from the short circuit detection units 260_1 to 260_3, and outputs the selection signal S to the second multiplexer 134.

[0173] As an example, such as Figure 9 As shown, when the LED channel voltage V_CH is between the second reference voltage VREF_2 and the third reference voltage VERF_3, the short circuit detection units 260_1 to 260_3 determine that the short circuit degree of the LED is at the second level, and generate a selection signal S for selecting the second brightness compensation amount LCD2 mapped to the second level of short circuit degree, and output the selection signal S to the second multiplexer 134.

[0174] According to the above implementation method, such as Figure 7 and Figure 10 As shown, the data controller 126 adds a brightness compensation amount output from the second multiplexer 134 to the on-state segment of the first PWM control signal PWM_1 of the first PWM switch 230_1 to be supplied to the target channel line CL1. t, to generate the final first PWM control signal PWM_1', and supply the generated final first PWM control signal PWM_1' to the first PWM switch 230_1 of the target channel line CL1. Therefore, the first PWM switch 230_1 connected to the target channel line CL1 is also turned on for brightness compensation. Therefore, when LEDs L12 and L13 emit light normally, the duration for which the first channel voltage V_CH1 remains at its maximum value increases the brightness compensation amount. This increases the brightness of normal LEDs L12 and L13. In this case, the brightness compensation amount... t can be any value corresponding to the first brightness compensation amount LCD1 to the nth brightness compensation amount LCDn.

[0175] As an example, such as Figure 9 As shown, the data controller 126, which outputs a second brightness compensation amount LCD2 from the brightness compensation unit 130, adds the brightness compensation amount LCD2 output from the second multiplexer 134 to the on-state of the initial PWM control signal to generate a final PWM control signal, and supplies the generated final PWM control signal to the PWM switch of the target channel line. Therefore, the PWM switch connected to the target channel line additionally activates the brightness compensation amount LCD2, thus increasing the brightness of the normal LED by increasing the duration during which the channel voltage V_CH remains at its maximum value when the normal LED emits light.

[0176] In addition, such as Figure 10 As shown, when the final first PWM control signal PWM_1' is generated, the data controller 126 may additionally reflect the offset value stored in the offset register 850 to the initial first PWM control signal PWM_1.

[0177] In the above implementation, it is described that the initial first PWM control signal PWM_1 only increases the brightness compensation amount during its on-state. However, the initial PWM control signal PWM_1's on-time segment can also reduce the brightness compensation amount. t.

[0178] As stated above, according to this disclosure, such as Figure 16A and Figure 16B As shown, only the point defect (point darkness) occurs where only the short-circuited LED does not emit light, and the line defect (line darkness) prevents all other normal LEDs connected to the target channel line connected to the short-circuited LED from changing their brightness, thus achieving near-normal image quality without repairing or replacing the LED.

[0179] According to this disclosure, since multiple reference voltages with different voltage levels are used to detect LED short circuits, not only can fully short-circuited LEDs be accurately detected, but also partially short-circuited LEDs can be accurately detected.

[0180] Furthermore, according to this disclosure, by floating the target scan line connected to the short-circuited LED during the non-light-emitting period of the short-circuited LED, line defects (dark lines) that cause brightness changes in all other normal LEDs connected to the same channel line as the short-circuited LED can be prevented, thereby achieving near-normal image quality without repairing or replacing the short-circuited LED.

[0181] Furthermore, according to this disclosure, when a normal LED connected to a target channel line emits light, the brightness of the normal LED can be compensated using different brightness compensation amounts depending on the degree of short circuit of the short-circuited LED, thereby preventing under-compensation or over-compensation of the brightness of the normal LED and preventing image quality degradation due to LED short circuit.

[0182] Cross-reference of related applications

[0183] This application claims the benefit of Korean Patent Application No. 10-2024-0166584, filed November 20, 2024, and Korean Patent Application No. 10-2025-0056950, filed April 30, 2025, which are incorporated herein by reference as fully set forth herein.

Claims

1. A light-emitting diode (LED) display driving circuit, the LED display driving circuit comprising: A channel driving circuit is configured to supply channel current to each of the multiple channel lines to which multiple LEDs are connected, according to a pulse width modulation (PWM) control signal. A scan driving circuit includes a plurality of scan switches configured to selectively drive each scan line to cause the plurality of LEDs to emit light, and a plurality of precharge switches turned on when the scan switches are turned off and supply a precharge voltage to the scan lines. A short-circuit detection unit is configured to detect whether the plurality of LEDs are short-circuited and the degree of short circuit. When a short-circuit LED is detected, the data controller turns off the pre-charge switch of the target scan line when the scan switch of the target scan line to which the short-circuit LED is connected is turned off, and maintains the target scan line in a floating state. as well as A brightness compensation unit is configured to compensate the brightness of a normal LED connected to a target channel line to which the short-circuited LED is connected, based on the degree of short circuit of the short-circuited LED, during the driving of the scan lines other than the target scan line.

2. The LED display driving circuit according to claim 1, wherein, When a specific scan line is driven by the scan driving circuit, the short-circuit detection unit detects whether the LED is short-circuited and the degree of short circuit by comparing the channel voltage of each channel line with multiple reference voltages at different voltage levels.

3. The LED display driving circuit according to claim 1, wherein, The short-circuit detection unit includes: A reference voltage generation unit is configured to generate multiple reference voltages of different voltage levels; A comparator configured to compare any one of the plurality of reference voltages with the channel voltages of each channel line; and A determining unit is configured to determine whether the LED is short-circuited and the degree of short circuit based on the comparison result of the comparator.

4. The LED display driving circuit according to claim 3, wherein, A frame is divided into multiple segments and driven, and The short-circuit detection unit further includes a first multiplexer configured to select, based on a selection signal input from the data controller, a reference voltage mapped to each segment from among the plurality of reference voltages and to output the selected reference voltage to the comparator during the driving of each segment.

5. The LED display driving circuit according to claim 1, wherein, A frame is divided into multiple segments and driven. When driving the scan line for each segment, the short-circuit detection unit uses the reference voltage supplied to each channel line during the segment before the PWM control signal is supplied to the channel line to detect whether the LED is short-circuited and the degree of the short circuit. The reference voltage has a reference voltage level higher than the ground level.

6. The LED display driving circuit according to claim 1, wherein, The brightness compensation unit includes: A register in which the brightness compensation amount is mapped according to the short circuit degree; A brightness compensation amount selection unit, configured to generate a selection signal for selecting a brightness compensation amount corresponding to the short-circuit degree; and A second multiplexer is configured to select a brightness compensation amount corresponding to the short-circuit degree from the register in response to the selection signal and output the brightness compensation amount. The data controller generates a final PWM control signal for controlling the PWM switch connected to the target channel line by adjusting the selected brightness compensation amount in the on-state of the initial PWM control signal.

7. The LED display driving circuit according to claim 1, wherein, The channel driving circuit includes: Multiple channel current sources, each channel current source being configured for a specific channel line and configured to use an externally supplied voltage to generate the channel current to be supplied through each channel line; and Multiple PWM switches are connected between each channel line and its corresponding channel current source, and are turned on or off according to the PWM control signal to control the amount of channel current supplied to each channel line. The data controller generates the PWM control signal to turn off the PWM switch of the target channel line to which the short-circuited LED is connected during the on-state of the scan switch on the target scan line.

8. The LED display driving circuit according to claim 1, wherein, When a specific scan line is selected by the scan drive circuit, the channel voltage of each channel line, based on the channel current supplied through each channel line, increases from a reference voltage level above ground level as the channel current increases, and decreases to the reference voltage level when the supply of the channel current stops.

9. A light-emitting diode (LED) display device, the LED display device comprising: The display panel includes multiple LEDs; as well as An LED display driver circuit is configured to supply channel current to the plurality of LEDs so that the plurality of LEDs emit light. The LED display driving circuit includes: A channel driving circuit configured to supply channel current through each channel line according to a pulse width modulation (PWM) control signal; A scan driving circuit includes a plurality of scan switches configured to selectively drive each scan line to cause the plurality of LEDs to emit light, and a plurality of precharge switches turned on when the scan switches are turned off and supply a precharge voltage to the scan lines. A short-circuit detection unit is configured to detect whether the plurality of LEDs are short-circuited and the degree of short circuit. A data controller, upon detecting a short-circuited LED, turns off the pre-charge switch of the target scan line when the scan switch of the target scan line to which the short-circuited LED is connected is turned off, and maintains the target scan line in a floating state; and A brightness compensation unit is configured to compensate the brightness of a normal LED connected to a target channel line to which the short-circuited LED is connected, based on the degree of short circuit of the short-circuited LED, during the driving of the scan lines other than the target scan line.

10. The LED display device according to claim 9, wherein, A frame is divided into multiple segments and driven, and The short-circuit detection unit includes: A reference voltage generation unit is configured to generate multiple reference voltages of different voltage levels; A comparator configured to compare any one of the plurality of reference voltages with the channel voltage of each channel line; A first multiplexer is configured to select, based on a selection signal input from the data controller, one of a plurality of reference voltages mapped to each segment, and to output the selected reference voltage to the comparator during the driving of each segment; and A determining unit is configured to determine whether the LED is short-circuited and the degree of short circuit based on the comparison result of the comparator.

11. The LED display device according to claim 9, wherein, The brightness compensation unit includes: A register in which the brightness compensation amount is mapped according to the short circuit degree; A brightness compensation amount selection unit, configured to generate a selection signal for selecting a brightness compensation amount corresponding to the short-circuit degree; and A second multiplexer is configured to select a brightness compensation amount corresponding to the short-circuit degree from the register in response to the selection signal, and The data controller generates a final PWM control signal for controlling the PWM switch connected to the target channel line by adjusting the selected brightness compensation amount in the on-state of the initial PWM control signal.

12. The LED display device according to claim 9, wherein, A frame is divided into multiple segments and driven. When driving the scan line for each segment, the short-circuit detection unit uses the reference voltage supplied to the channel line during the segment before the PWM control signal is supplied to the channel line to detect whether the LED is short-circuited and the degree of the short circuit. The reference voltage has a reference voltage level higher than the ground level.

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