KR200342197Y1 - Electronic display board system using surface mount device type of light emitting diode - Google Patents

Abstract

The electronic display system of the present invention comprises an LED display panel in which surface-mounted light emitting diodes are arranged in a dot matrix form, an LED display module including two drive control circuits of the same type for driving the LED display panel, and an input from an external device. And converting the applied image signal into a signal suitable for the LED display module, and including an LED display module controller for controlling the operation of the LED display module. Each of the driving control circuits of the LED display module includes a duty to be displayed. It can be selectively operated according to the ratio, and each has a PWM circuit for gray scale display.

Description

Surface-mount light emitting diode display system {ELECTRONIC DISPLAY BOARD SYSTEM USING SURFACE MOUNT DEVICE TYPE OF LIGHT EMITTING DIODE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic display system capable of displaying a full color video, and more particularly, an electronic display system for displaying an image using a surface mount device (SMD) light emitting diode (LED). It is about.

The electronic signboard system displays LEDs, small fluorescent tubes, etc. in a matrix form, and displays information such as various characters and pictures, and receives video signals from AV devices such as DVDs, VCRs, and broadcast equipment. In addition, the received signal is converted into a signal for LED suitable for an electric sign in an LED display module controller, and then an LED is emitted according to the signal to display an image.

The LED display module integrates a display unit on which an LED is mounted and a driving circuit unit. The LED display module is configured by vertically and horizontally arranging such LED display modules as necessary. Since the conventional outdoor billboard system mostly uses lamp type LEDs, the size of the LED display module is also large.

Recently, a lot of indoor video display boards have been developed using SMD LEDs. The SMD type has better resolution than the lamp type and can reduce the manufacturing cost of the LED display module by almost half.

In general, the outdoor display board is driving the LED panel in a static (Static) method to achieve a high brightness. However, since the indoor display board does not need to have a high luminance, the indoor display board may be driven by lowering the horizontal line driving duty ratio of the LED display panel.

In a conventional LED board system using SMD LED, a general-purpose integrated circuit (IC) is used as a driving element used in the LED display module. When driving SMD LEDs using a general purpose IC, a large number of driving devices are required to display a full color video. For example, 48 LED drivers are required to drive a 16 x 16 dot matrix LED panel to achieve three colors: red, green, and blue (R, G, B).

However, since the LED display module of the conventional LED system does not have a gradation processing function and performs gradation processing in the LED display module controller, the LED display module controller needs to execute many tasks, so that the configuration of the controller is complicated and the load is increased.

Therefore, in order to display a full color image in a conventional signboard system, the design and manufacturing cost of the LED module controller becomes high, which in turn increases the manufacturing cost of the signboard system.

SUMMARY OF THE INVENTION The present invention is to solve the above problems of the display board system using the conventional SMD LED, and by providing a LED display module that can be grayscale processing using a dedicated IC, simplifying the design of the display board system, manufacturing cost The aim is to be able to reduce the

1 is a block diagram schematically showing a signboard system according to the present invention;

Figure 2 is a block diagram showing in detail the drive control circuit in the LED display module of the electronic display system according to the present invention.

Display board system of the present invention for achieving the above object is

An LED display module including surface-mounted LEDs arranged in a dot matrix form, and an LED display module including two drive control circuits of the same type for driving the LED display panels;

And an LED display module controller for converting and applying an image signal input from an external device into a signal suitable for the LED display module and controlling the operation of the LED display module.

Each of the driving control circuits of the LED display module may be selectively operated according to the duty ratio to be displayed, and each includes a PWM circuit for gray scale display.

Each of the drive control circuits

A shift register configured to receive and store input data for displaying and controlling an image on the LED display panel from the LED display module controller;

A video data memory for receiving and storing image data to be displayed on the LED display panel from the shift register;

A control data memory configured to receive and store control data for determining an operation mode of the driving control circuit through the shift register;

A PWM counter for performing pulse width modulation control on the video data of the video data memory;

The apparatus further includes a gradation clock generator for generating a clock for driving the PWM counter.

Each of the driving control circuits may further include a PWM amplitude controller that separates data stored in the video data memory into image data and luminance data and inputs the same to the PWM counter.

In the LED display module, it is preferable to drive the LED display panel in a horizontal line at a 1/8 duty ratio. Considering that the electronic display system according to the present invention is mainly installed indoors, when driving at a 1/8 duty ratio, an image having sufficient luminance can be displayed.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 1 and 2.

1 and 2 illustrate an example of driving a 16x16 LED display panel, and FIG. 1 is a block diagram schematically illustrating a signboard system according to an exemplary embodiment of the present invention, and FIG. 2 is a driving control circuit of the signboard system. It is shown in detail.

As shown in FIG. 1, the LED display system according to the present invention inputs an image signal, etc., input from an external AV device 10 to the LED display module 12 under the control of the LED display module controller 11, thereby displaying the LED display module. The LED at (12) is lit to display an image.

The LED display module 12 is composed of a 16x16 dot matrix LED panel 20 in which SMD type LEDs are arranged, and two drive control circuits 13 and 14 for driving the LEDs.

Next, the detailed structure of such a drive control circuit is demonstrated with reference to FIG.

In the driving control circuit of FIG. 2, first, setting signals for determining the overall operation of the driving control are input to the external input mode selector 23, and basic control signals and address signals A0 and A1 for controlling the operation of the driving control circuit. , A3 and A3 are input to the control signal buffer 22.

The signals input to the external input mode selector 23 include PIN / REGISTER and PRE1 / TEST signals for determining the input method of control data, and LINEOUT_N / P for determining the method of applying data to the line driver. There are a COLOUT_N / P signal, a POSITION0 to POSITION3 signal for determining an address corresponding to the position of each drive control circuit according to the duty ratio, and a DRIVE_MTRX signal for selecting output drive to the panel of the drive control circuit.

The control data is input and set through one of an external pin (PIN), an external controller (PRE1), and an internal register (REGISTER) according to the PIN / REGISTER and PRE1 / TEST signals. Here, the TEST signal is for testing the drive control circuit. Input through the external pin (PIN) is when some of the 30 bits of control data is set by the external pin (PIN) and the rest is set in advance internally, input through the external controller (PRE1) is 30 bits of control data All of them are stored in the internal memory through the shift register 21 to be described later, and an input through the internal register (REGISTER) represents a case where all 30 bits of control data are set in advance.

According to the LINEOUT_N / P signal, the driving element drives the output logic of the horizontal line to active low or active high, and likewise activates the output logic of the vertical line according to the COLOUT_N / P signal. Drive to active low or active high.

The DRIVE_MTRX signal determines whether the output drive is 1x16 drive or 2x8 drive.

The POSITION0 to POSITION3 signals determine the read address of the drive control circuit together with the duty mask data (4 bits here) of the control data, so that the horizontal line driving of the panel 20 can be performed at a predetermined duty ratio. do.

After the control signal for determining the overall operation of the drive control is input as described above, the input data R_DATA, G_DATA, B_DATA for turning on / off the LEDs of R, G, and B is 10 bits by the shift clock S_CLK. The input is input to the x3x16 shift register 21. Further, correction data, control data, etc. to be stored in the internal memory of the drive control circuit are also input through the shift register 21.

The shift register 21 may be set to shift registers of 1x3x16, 2x3x16, 4x3x16, 6x3x16, 8x3x16, and 10x3x16 bits in accordance with the control data. In addition, the input method can be converted in series and in parallel by the control data. In case of serial, all R, G, B data is input through R input terminal, and G, B input terminal is not used. Therefore, in this case, the number of input terminals (input pins) can be reduced.

In addition, the input data of the shift register 21 can be selected from 1 bit up to 10 bits. That is, data of 1, 2, 4, 6, 8, 10 bits can be selected according to the control data value stored in the control data memory 26. Therefore, by appropriately changing and inputting control data, only LED on / off driving is required to display only characters, and signals up to 10 bits (1024 gray scales) can be driven to display high quality video signals. Can be.

The data input through the shift register 21 is the video data memory 26, the correction data memory 50, and the control data, which are internal memories, according to control signals VD / CD, CRTL / BRT, and LATCH. Memory 27 and brightness and white balance memory 51, respectively.

The control signal VD / CD is a signal for selecting the video data memory 26 and the correction data memory 50, and the CTRL / BRT is a signal for selecting the control data memory 27 and the luminance and white balance memory 51. , LATCH is a signal to write data to memory.

The video data memory 26 is a memory in which 30x16x16 bits of data for displaying an image on an LED is stored, and the correction data memory 50 is 15x16x16 bits for color correction for each dot of the 16x16 dot matrix panel 20. The memory where data is stored. The video data memory 26 preferably uses dualport RAM in which data read / write is executed independently.

On the other hand, the control data memory 27 is a memory for storing 30-bit control data for determining an operation mode of the drive control circuit, and the luminance and white balance memory 51 is used for R, G, and R of the 16x16 bit dot matrix panel 20. It is a memory that stores 20-bit data for controlling the luminance and white balance of B colors.

The memory write address generator 24 generates data write addresses for the video data memory 26 and the correction data memory 50 according to the address signals A0 to A3, and controls them according to the generated addresses. The corresponding data is stored in the memory selected by the signals VD / CD and CRTL / BRT.

The data buffer 28 buffers the data stored in the video data memory 26 to be suitable for 1x16 driving or 2x8 driving.

The pulse width modulation (PWM) counter 29 performs pulse width modulation control on the data output from the data buffer 28 in accordance with the clock of the gradation clock generator 40 described later.

The gradation clock generator 40 is a circuit for generating a clock for driving the PWM counter 29 and includes a gradation clock generator 41, a gradation clock divider 42, and a gradation clock selector 43. The gray clock generator 40 selects an appropriate basic clock according to the clock of the self-oscillator and the external clock G_CLK input to the control signal buffer 22. The gradation clock generator 40 may increase or decrease the clock of the PWM counter 29 in multiples of 5 MHz to 80 MHz. Since the overall brightness of the LED panel 20 can be changed by such a clock change, the brightness of the LED panel can be easily adjusted by changing only the control data.

The luminance controller 52 receives 5-bit data stored in the luminance and white balance memory 51, divides the clock of the PWM counter 29, and adjusts the luminance of the LEDs of the panel 20. On the other hand, the white balance controller 53 receives the brightness and 15-bit data stored in the white balance memory 51, divides the clock of the PWM counter 29, and adjusts the white balance for the LED of the panel 20.

The dot correction controller 54 receives 5-bit data for each color stored in the correction data memory 50, divides the clock of the PWM counter 29, and corrects the color of each dot of the panel 20. FIG.

As described above, the PWM counter 29 is a video data memory by clock division by the gradation clock generator 40 and clock division by the luminance controller 52, the white balance controller 53, and the dot correction controller 54. PWM control is performed on the data in (26).

The PWM amplitude controller 30 uses the 10-bit input data stored in the video data memory 26 to separate the 8-bit image data and the 2-bit luminance data into the PWM counter 29. That is, the upper two bits of MSB are used to express the difference in brightness. Therefore, the lower image signal shows the same value as the data value, but the 256 or more image signal is displayed with more emphasis on the brightness. In other words, by using the PWM amplitude controller 30, the luminance correction can be simplified by only 10-bit image data, called Gamma Correction, which is generally used in image processing.

The function of the PWM amplitude controller 30 may be omitted as necessary.

The output of the PWM counter 29 is applied to the LED dot matrix panel 20 through the 16 dot x 3 color LED driving element 31, so that vertical line driving for the LED is performed.

At the same time, the memory read address generator 25 generates a memory read address in accordance with the 30-bit control data of the control memory. At this time, the memory read address is automatically generated in accordance with the control signal LOAD.

The memory read address is decoded by the display line address decoder 32 and applied to the LED dot matrix panel 20 through the 16-line driving element 33, so that the horizontal line driving for the LED is executed.

At this time, the watchdog timer 44 is for turning off the output of the driving element when the basic clock and other important signals for operating the PWM counter 29 are not input.

The driving control circuits 13 and 14 according to the present invention described above may be manufactured as an ASIC (Application Specific Integrated Circuit), and thus may be easily mounted on the LED display module. Further, in order to selectively use the duty ratio in the horizontal line driving of the LED panel, the operation of each driving control circuit can be adjusted as necessary. This will be described in detail below.

As mentioned above, the duty mask data of the POSITION0 to POSITION3 signals and the control data is input to the memory read address generator 25, and the read address for each drive control circuit is determined according to the LOAD signal. The determined address is input to the display line address decoder 32 and decoded to drive the corresponding line of the panel 20.

When only one drive control circuit is operated, the horizontal line of the 16x16 dot matrix LED panel is driven at a duty ratio of 1/16, and when the two drive control circuits are operated, it is driven at a duty ratio of 1/8. That is, when only one drive control circuit is operated, all of the 16 lines are driven at a duty ratio of 1/16 by sequentially displaying the drive control circuit, and when the two drive control circuits are operated, one is higher than the LED panel. It is responsible for the display of eight lines, and the other one is responsible for displaying the lower eight lines, and is driven at a 1/8 duty ratio.

In consideration of the brightness of the light-emitting plate, in the present invention, it is preferable to set it to the 1/8 duty ratio. In fact, in the case of the indoor electronic display board, when driven at the 1/8 duty ratio, a sufficiently bright image can be displayed.

As described above, the present invention can simplify the design of the system and reduce the manufacturing cost by configuring 48 LED driving elements as two ASICs while showing sufficient brightness in the SMD LED display board used for indoor use. .

In addition, a built-in PWM circuit for executing gray scale display in the LED display module enables the display of a large number of modules with only one set of controllers, thereby reducing the load on the LED display module controller.

In addition, in the conventional electronic display system, one driving element for driving the LED display module itself is driven at 1/16 duty for each of R, G, and B, but in the LED display module of the present invention, two driving control circuits are provided. Can be driven at 1/8 duty ratio. In addition, the frequency of the gradation clock can be adjusted for each duty ratio, thereby reducing image quality deterioration.

In addition, the LED display system according to the present invention can be manufactured at a low cost LED display module controller, it is possible to apply a standardized drive control method to the LED display system.

Although the present invention has been described with reference to the above-described preferred embodiments and the accompanying drawings, different embodiments may be constructed within the spirit and scope of the invention. Accordingly, the scope of the invention is defined by the appended claims, and should be construed as not limited by the specific embodiments described herein.

Claims (5)

An LED display module comprising a surface mounted light emitting diode (SMD LED) arranged in a dot matrix form, and an LED display module including two drive control circuits of the same type for driving the LED display panel; And converts and applies an image signal input from an external device into a signal suitable for the LED display module, and includes an LED display module controller controlling the operation of the LED display module. Each of the driving control circuits of the LED display module may be selectively operated according to the duty ratio to be displayed, and each of the driving control circuits includes a PWM circuit for gray scale display. The method of claim 1, wherein each of the drive control circuits A shift register for receiving and storing input data for displaying and controlling an image on the LED display panel from the LED display module controller; A video data memory for receiving and storing image data to be displayed on the LED display panel from the shift register; A control data memory configured to receive and store control data for determining an operation mode of the driving control circuit through the shift register; A PWM counter for performing pulse width modulation control on the video data of the video data memory, and And a gradation clock generator for generating a clock for driving the PWM counter. 3. The driving control circuit of claim 2, wherein each of the driving control circuits And a PWM amplitude controller which separates the data stored in the video data memory into image data and luminance data and inputs the same to the PWM counter. The method according to claim 2 or 3, A correction data memory for receiving and storing data for color correction for each dot of the LED display panel from the shift register; A luminance and white balance memory for receiving and storing data for adjusting luminance and white balance of the LED of the LED display panel from the shift register; A luminance controller which receives data stored in the luminance and the white balance memory, divides the clock of the PWM counter, and adjusts the luminance of the LED of the LED display panel; A white balance controller which receives data stored in the brightness and white balance memory, divides the clock of the PWM counter, and adjusts the white balance of the LED of the LED display panel; And a dot correction controller which receives data stored in the correction data memory, divides the clock of the PWM counter, and corrects the color of each dot of the LED display panel. The method according to claim 2 or 3, The LED display module is characterized by driving the LED display panel in a horizontal line at a 1/8 duty ratio.