Apparatus and method for compensating for voltage drop in active matrix LED signage

Abstract

Disclosed are an apparatus and a method for compensating for a voltage drop in active matrix light-emitting diode (LED) signage. According to one aspect of the present embodiment, provided is a display device comprising: a timing control unit that receives signals and power for display from the outside and transmits a scan signal, a data signal, and power; optical modules that operate by receiving the scan signal, the data signal, and the power; a data driver that receives the data signal from the timing control unit and applies the data signal to the optical modules; a scan driver that applies the scan signal, received from the timing control unit, to the optical modules; and a power control unit that transmits applied power to each of the optical modules and compensates for a voltage drop that may occur when the power is applied.

Description

Device and method for compensating voltage drop of active LED signage

[0001] The present embodiment relates to a compensation device and method capable of compensating for voltage drop occurring in an active driving LED signage.

[0002] The content described in this section merely provides background information for the present embodiment and does not constitute prior art.

[0003] Recently, the trend toward larger display areas and higher resolutions in the implementation of commercial outdoor and indoor electronic billboards has been developing. Furthermore, electronic billboards utilize LEDs as light-emitting elements to achieve high brightness, high contrast ratio, and excellent color reproducibility.

[0004] There is a growing need for display devices to adopt active matrix displays, including active-driven LEDs. Active matrix displays use active elements to control the horizontal and vertical axes, rather than directly controlling the LEDs configured in each pixel. Consequently, active matrix displays offer the advantage of significantly reducing the number of control pins compared to passive matrix displays. Consequently, the driving circuitry is greatly simplified, significantly contributing to reduced pixel size and pixel spacing, while simultaneously reducing power consumption.

[0005] However, when voltage is applied to an LED package including an active-drive LED, a voltage drop inevitably occurs in the voltage applied to the LED. If a voltage drop occurs in the applied voltage, a situation may arise where the applied voltage exceeds the operating voltage of the PDIC within the package. This may result in the PDIC not operating or the voltage applied to the LED being reduced, causing current changes, which in turn causes differences in the expression of brightness gradation.

[0006] In particular, since the voltage drop increases as the length of a horizontal axis increases and distance from the power source increases, the voltage drop becomes greater / more severe as the axis approaches its end. As a result, the voltage difference between the starting and ending points of the axis becomes significant.

[0007] These problems are a major obstacle to the development of large-area displays that include LED packages, such as signage systems.

[0008] One embodiment of the present invention aims to provide a device and method for compensating for voltage drop that inevitably occurs in an active driving LED signage.

[0009] According to one aspect of the present embodiment, a display device is provided, characterized by including a timing control unit that receives a signal and power for display from the outside and transmits a scan signal, a data signal, and the power, an optical module that operates by receiving the scan signal, the data signal, and the power, a data driver that receives a data signal from the timing control unit and applies it to the optical module, a scan driver that applies a scan signal received from the timing control unit to the optical module, and a power control unit that transmits the applied power to each optical module and compensates for a voltage drop that may occur when the power is applied.

[0010] According to one aspect of the present embodiment, the optical module is characterized by including one or more scan signal lines, one or more data signal lines, one or more power lines, one or more ground lines, one or more active driving LED modules, and one or more sensors.

[0011] According to one aspect of the present embodiment, the sensor is characterized in that it is located at the end of each power line.

[0012] According to one aspect of the present embodiment, the power control unit is characterized in that it receives a sensing value from the sensor and determines whether a voltage drop has occurred.

[0013] According to one aspect of the present embodiment, the power control unit is characterized in that it determines whether the sensing value is greater than a preset reference value.

[0014] According to one aspect of the present embodiment, a method for compensating for a voltage drop of a power supply in an optical module in which a display device operates by receiving a scan signal, a data signal, and a power supply is provided, the method comprising: a sensing process for sensing a voltage applied to a power line in the optical module; a judgment process for determining whether a sensed value sensed in the sensing process is greater than a preset reference value; and, if the sensed value sensed in the sensing process is less than the preset reference value, an application process for additionally applying a voltage equal to the difference between the two values ​​to the power supplied to the corresponding power line.

[0015] According to one aspect of the present embodiment, the optical module is characterized by including one or more scan signal lines, one or more data signal lines, one or more power lines, one or more ground lines, one or more active driving LED modules, and one or more sensors.

[0016] According to one aspect of the present embodiment, the sensing process is characterized in that it is performed at the end of each power line in the optical module.

[0017] According to one aspect of the present embodiment, the preset reference value is characterized by being a minimum voltage level that does not cause an error in grayscale expression in all LED packages connected to any one scan signal line.

[0018] As described above, according to one aspect of the present embodiment, there is an advantage in that the voltage drop of the applied voltage that inevitably occurs in the active driving LED signage can be compensated for, thereby minimizing the change in the grayscale expression that occurs due to the voltage drop of the applied voltage.

[0019] FIG. 1 is a plan view illustrating the configuration of a display device according to one embodiment of the present invention.

[0020] FIG. 2 is a diagram illustrating the configuration of a power control unit according to one embodiment of the present invention.

[0021] FIG. 3 is a drawing illustrating the structure of an optical module according to one embodiment of the present invention.

[0022] FIG. 4 is a drawing illustrating the structure of a switch in an optical module according to one embodiment of the present invention.

[0023] FIG. 5 is a flowchart illustrating a method for a power control unit according to one embodiment of the present invention to compensate for a voltage drop occurring in an LED package.

[0024] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0025] Terms such as first, second, A, and B may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term "and / or" includes a combination of multiple related items described herein or any of multiple related items described herein.

[0026] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0027] The terminology used in this application is solely for the purpose of describing specific embodiments and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. It should be understood that terms such as "comprise" or "have" in this application do not preclude the presence or possibility of addition of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification.

[0028] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0029] Terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0030] In addition, each configuration, process, procedure or method included in each embodiment of the present invention may be shared within a scope that is not technically inconsistent with each other.

[0031] FIG. 1 is a plan view illustrating the configuration of a display device according to one embodiment of the present invention.

[0032] Referring to FIG. 1, a display device (100) according to one embodiment of the present invention includes a timing control unit (110), a data driver (120), a scan driver (130), a power control unit (140), and an optical module (150).

[0033] The display device (100) is a device that can output light while minimizing errors in grayscale expression, and can be implemented as, for example, a transparent signage device.

[0034] The timing control unit (110) receives signals for display and power for the operation of the optical module from the outside, transmits the signals for display to the data driver (120) and the scan driver (130), and transmits the power to the power control unit (140). The timing control unit (110) can receive signals for display from the outside, for example, signals in HDMI format. The timing control unit (110) analyzes the received signals and transmits scan signals and data signals for operating the optical module (150) to the data driver (120) and the scan driver (130), respectively.

[0035] The data driver (120) applies a data signal received from the timing control unit (110) to the optical module (150). The data driver (120) converts the received data signal into a form suitable for the operation of the optical module (150) (e.g., size or direct current / alternating current, etc.). The data driver (120) applies the converted data signal to the optical module (150) so that the light source within the optical module (150) irradiates light of appropriate brightness and wavelength.

[0036] The scan driver (130) applies a scan signal received from the timing control unit (110) to the optical module (150).

[0037] The power control unit (140) transmits the applied power to each optical module (150). Typically, the power is applied to a large number of optical modules (150) arranged in the same row. As the number of optical modules (150) arranged in the same row (or connected to the same power line) increases, the length of the conductor (wire) for transmitting the power increases. When the power is long, the resistance of the conductor is relatively small up to the optical module (150) arranged relatively forward in the same row, whereas the resistance of the conductor becomes relatively significantly large up to the optical module (150) arranged relatively backward in the same row. As a result, almost no voltage drop occurs when power is transmitted to the optical module (150) arranged relatively forward in the same row, whereas a significant voltage drop may occur when power is transmitted to the optical module (150) arranged relatively backward in the same row. If the conductor has a sufficient width (or radius) to transmit power to all the optical modules, the aforementioned problem may not occur. However, since there is a limitation on increasing the size of the display device (100), the conductor width cannot be sufficiently increased, and thus the aforementioned voltage drop is bound to occur. In addition, since power is sequentially transmitted to each optical module (150) within the same row, power may be applied to the optical module (150) in the front, causing a voltage drop. An unintended voltage drop may occur in the power transmitted to the optical module (150) located relatively later within the same row.

[0038] In recognition of this problem, the power control unit (140) receives a sensing value for the magnitude of the power from the optical module (150) before applying power to the optical module (150). The power control unit (140) determines whether the magnitude of the power input to the optical module (150), particularly the optical module (150) located at the last end in the same row, is greater than a preset reference value due to a voltage drop. Here, the preset reference value means the minimum voltage magnitude that can prevent errors in grayscale expression from occurring in all LED packages connected to one row (or one power line). Based on the determination result, the power control unit (140) compensates for the magnitude of the input voltage to be applied to the power input terminal, particularly the optical module located at the last end in one row, to be greater than the preset reference value, thereby preventing errors in the grayscale expression of the optical module (150). The specific structure and operation of the power control unit (140) will be described later with reference to FIG. 2.

[0039] The optical module (150) operates by receiving a data signal from the data driver (120), a scan signal from the scan driver (130), and power for operation from the power control unit (140). The optical module (150) includes a plurality of active driving LED packages, as described later with reference to FIGS. 3 and 4, and controls the operation of each LED package depending on whether a scan signal, a data signal, and power are applied. At this time, since all optical modules (150) receive power compensated to be at least greater than a preset reference value from the power control unit (140), conventional problems due to voltage drop can be minimized. The specific structure of the optical module (150) will be described later with reference to FIGS. 3 to 5.

[0040] FIG. 2 is a diagram illustrating the configuration of a power control unit according to one embodiment of the present invention.

[0041] Referring to FIG. 2, a power control unit (140) according to one embodiment of the present invention includes a control unit (210), a first converter (220), and a second converter (230).

[0042] The control unit (210) controls the operation of each component within the power control unit (140), and compensates for the size of the power by receiving sensing values ​​from sensors (described later with reference to FIG. 3) within each power line of the optical module (150).

[0043] The control unit (210) receives a sensing value regarding the magnitude of the voltage from a sensor in each power line of the optical module (150). The control unit (210) determines whether the received sensing value is greater than a preset reference value. As described above, the preset reference value is the minimum voltage magnitude that all LED packages in the corresponding power line can have without causing an error in the grayscale expression. Therefore, the above-described error can be avoided if the sensing value is at least greater than the preset reference value. If the sensing value is greater than the preset reference value, it means that even if a voltage drop occurs, the magnitude of the power applied to each optical module (150) from each power line is sufficient to not cause the above-described error. However, if the opposite is the case, at least some of the corresponding power lines (LED packages located at the rear end of the power line) are causing the above-described error. To prevent this, the control unit (210) calculates the difference between the preset reference value and the sensing value and controls the first converter (220) or the second converter (230) to increase the power level by the calculated difference value and transmit it. Accordingly, even if a voltage drop occurs in the power supply as it passes through each LED package, all LED packages connected to the same power line can receive power that is at least greater than the preset reference value.

[0044] The first converter (220) and the second converter (230) increase or decrease the magnitude of the voltage to be output according to the control of the control unit (210). For example, the first converter (220) is implemented as a buck converter, and the second converter (230) is implemented as an inverting buck converter, and thus the magnitude of the power to be applied to one power line is adjusted according to the control of the control unit (210). The power to be applied to one power line through the first converter (220) and the second converter (230) can be adjusted to be applied to all light source units (150) connected to one power line to be greater than a preset reference value.

[0045] FIG. 3 is a drawing illustrating the structure of an optical module according to one embodiment of the present invention, and FIG. 4 is a drawing illustrating the structure of a switch in an optical module according to one embodiment of the present invention.

[0046] Referring to FIG. 3, an optical module (150) according to one embodiment of the present invention includes a scan signal line (310), a data signal line (320), a power line (330), a ground line (340), an active driving LED package (350, hereinafter abbreviated as 'LED package') and a sensor (360).

[0047] The scan signal line (310) applies a scan signal to each LED package (350) in the row direction. The scan signal line (310) applies a scan signal applied from the scan driver (130) to each LED package (350) electrically connected to it.

[0048] The data signal line (320) applies a data signal to each LED package (350) in the column direction. A data signal is applied from the data driver (120) to each data signal line (320). The data signal line (320) applies the data signal applied from the data driver (120) to each LED package (350) electrically connected thereto.

[0049] The power line (330) supplies power to each LED package (350) in the row direction so that each LED package (350) can operate. As described above, power having a magnitude greater than the previously set standard is supplied to each power line (330), and each power line (330) supplies power to each LED package (350) connected to it.

[0050] The ground line (340) enables power to be supplied to all LED packages (350) that are (electrically) connected to it together with the power line (330).

[0051] The LED package (350) receives power, data signals, and scan signals and operates according to the data signals and scan signals. The LED package (350) includes a driving driver IC for controlling the operation of a light source within it, thereby enabling it to control the operation of the light source on its own according to the scan signal and data signal.

[0052] The sensor (360) is located at the end of the power line (330) (the end opposite to the side where power is first input to the power line) to sense the size of the power and control whether or not the control unit (210) and each power line are electrically connected.

[0053] The sensor (360) may be implemented as a BJT (Bipolar Junction Transistor) as illustrated in Fig. 4(a). The base terminal of the sensor (360) may be electrically connected to the end of the power line (330), the emitter terminal may be electrically connected to the ground terminal, and the collector terminal may be electrically connected to the control unit (210). In order to determine how much power is supplied to the end of each power line, each power line (330) and the control unit (210) must all be electrically connected. In this case, if all power lines (330) and the control unit (210) are electrically connected without a separate switch, power lines other than the power line to which power is supplied may cause a slight error in the measured value.

[0054] To prevent this, each sensor (360) is placed at the end of each power line (330) and controls whether or not there is an electrical connection between the power line (330) and the control unit (210). When power is applied to the power line (330), the sensor (360) implemented as a BJT generates current only when power is applied to the power line (330) and electrically connects the power line (330) and the control unit (210). Accordingly, the sensor (360) generates a current proportional to the magnitude of the applied power. Accordingly, the control unit (210) can receive a sensing value from the sensor (360) and determine how much power is applied to the power line (330), particularly, to the end of the power line (330).

[0055] Meanwhile, the sensor (360) may be implemented as a FET (Field Effect Transistor) as illustrated in Fig. 4(b). The gate terminal of the sensor (360) may be electrically connected to the end of the power line (330), the source terminal may be electrically connected to the ground terminal, and the drain terminal may be electrically connected to the control unit (210). Accordingly, the sensor (360) may also operate in the same manner as the sensor illustrated in Fig. 4(a).

[0056] Referring back to FIG. 3, as the sensor (360) is implemented as illustrated in FIG. 4, it senses the magnitude of the applied power and simultaneously controls whether the control unit (210) and each power line (330) are electrically connected. The sensor (360) senses the magnitude of the power that has undergone a voltage drop through each LED package at the end of the power line (330) and transmits the sensed magnitude to the control unit (210). The control unit (210) receives the sensed value (output value of the sensor) of the sensor (360) and can calculate the difference between the preset reference value and the sensed value. When applying power to the corresponding power line, the control unit (210) increases the magnitude of the voltage to be applied by at least the calculated difference value and applies the voltage to the corresponding power line. Accordingly, the LED package connected to the corresponding power line can receive at least a sufficient magnitude of voltage when receiving a data signal.

[0057] The control unit (210) sequentially performs the above-described process on all power lines to compensate for voltage drops in all power lines.

[0058] FIG. 5 is a flowchart illustrating a method for a power control unit according to one embodiment of the present invention to compensate for a voltage drop occurring in an LED package.

[0059] The control unit (210) senses the voltage applied to each power line (S510). The control unit (210) receives the sensing value obtained by sensing the aforementioned voltage from the sensor (360).

[0060] The control unit (210) determines whether the sensing value is greater than a preset reference value (S520). If the sensing value is greater than the preset reference value, it means that sufficient power is being supplied to all LED packages connected to the corresponding power line.

[0061] If the sensing value is smaller than the preset reference value, the control unit (210) additionally applies voltage equal to the difference between the two values ​​to the power applied to the corresponding power line (S530). If the sensing value is smaller than the preset reference value, the difference between the two values ​​is additionally applied to the power to be applied so that sufficient power can be applied to all LED packages connected within the corresponding power line (particularly, LED packages located at the rear end of the corresponding power line). Accordingly, the control unit (210) ensures that power having at least the preset reference value can be applied to each LED package.

[0062] Although FIG. 5 describes each process as being executed sequentially, this is merely an illustrative description of the technical idea of ​​one embodiment of the present invention. In other words, a person of ordinary skill in the art to which one embodiment of the present invention pertains can modify and apply various modifications and variations, such as changing the order described in each drawing and executing the process, or executing one or more of the processes in parallel, without departing from the essential characteristics of one embodiment of the present invention. Therefore, FIG. 5 is not limited to a chronological order.

[0063] Meanwhile, the processes illustrated in FIG. 5 can be implemented as computer-readable code on a computer-readable recording medium. A computer-readable recording medium includes all types of recording devices that store data that can be read by a computer system. That is, a computer-readable recording medium includes storage media such as magnetic storage media (e.g., ROM, floppy disks, hard disks, etc.) and optical reading media (e.g., CD-ROMs, DVDs, etc.). In addition, a computer-readable recording medium can be distributed across network-connected computer systems, so that the computer-readable code can be stored and executed in a distributed manner.

[0064] The above description is merely an example of the technical idea of ​​the present embodiment, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of ​​the present embodiment, but rather to explain it, and the scope of the technical idea of ​​the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of the present embodiment.

[0065]

[0066] CROSS-REFERENCE TO RELATED APPLICATION

[0067] This patent application claims priority under 35 USC § 119(a) to Korean Patent Application No. 10-2024-0072377, filed in Korea on June 3, 2024, the entire contents of which are incorporated by reference herein. Furthermore, this patent application claims priority in countries other than the United States for the same reasons, the entire contents of which are incorporated by reference herein.

Claims

1. A timing control unit that receives signals and power for display from the outside and transmits scan signals, data signals, and power; An optical module that operates by receiving the above scan signal, data signal, and power; A data driver that receives a data signal from the timing control unit and applies it to the optical module; A scan driver that applies a scan signal received from the timing control unit to the optical module; and A power control unit that transmits the applied power to each optical module and compensates for voltage drops that may occur when the power is applied. A display device characterized by including:

2. In paragraph 1, The above optical module, A display device comprising one or more scan signal lines, one or more data signal lines, one or more power lines, one or more ground lines, one or more active driving LED modules, and one or more sensors.

3. In paragraph 2, The above sensor, A display device characterized by being located at the end of each power line.

4. In paragraph 3, The above power control unit, A display device characterized in that it receives a sensing value from the above sensor and determines whether a voltage drop has occurred.

5. In paragraph 4, The above power control unit, A display device characterized by determining whether a sensing value is greater than a preset reference value.

6. In a method for compensating for voltage drop of power in an optical module in which a display device operates by receiving scan signals, data signals, and power, A sensing process for sensing the voltage applied to the power line in the above optical module; A judgment process for determining whether the sensed value sensed in the above sensing process is greater than a preset reference value; and If the sensing value sensed in the above sensing process is less than the preset reference value, an additional voltage is applied to the power supplied to the corresponding power line equal to the difference between the two values. A voltage drop compensation method of a power source, characterized by including:

7. In paragraph 6, The above optical module, A method for compensating for voltage drop in a power supply, characterized in that it includes one or more scan signal lines, one or more data signal lines, one or more power lines, one or more ground lines, one or more active driving LED modules, and one or more sensors.

8. In paragraph 7, The above sensing process is, A method for compensating for voltage drop in a power supply, characterized in that it is performed at the end of each power line in the above optical module.

9. In paragraph 6, The above-mentioned preset standards are: A voltage drop compensation method of a power supply characterized in that all LED packages connected to a single scan signal line have a minimum voltage level that does not cause an error in grayscale expression.

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