KR20010002238U - An error detection circuit of electric board - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

Relates to a fault detection circuit of an all-optical display device

2. The technical problem that the draft is trying to solve

According to the present invention, a fault detection circuit of an all-optical display device connected to the display unit of the display panel in parallel with the pixel driving unit, which can detect a fault even when the display unit is turned off, and the current display state are checked in real time, so that information output is desired. Provides a display state detection technique for an all-optical display device that can check whether or not it is output

3.summary of the solution of this invention

The failure detection device of the present invention comprises: drive means for driving a display element provided in the all-optical display device; Voltage dividing means connected between an output terminal of the display element and a ground to divide a voltage; And detection means connected to the voltage dividing means to detect whether or not the display element has failed.

4. Significant use of the design

The present invention is used for detecting a defective pixel position and display state of an all-optical display device.

Description

Fault detection circuit of an all-optical display device

The present invention relates to a failure detection circuit of an all-optical display device.

In general, an all-optical display device includes light emitting elements such as color light emitting diodes (LEDs), small fluorescent tubes, and the like, arranged in a matrix, and outputs various image information such as text, still images, or moving image graphics. do.

In recent years, as the size of the all-optical display device is enlarged, a large number of remote display units are located in remote places far from the location where the central control unit (host computer) is installed, as shown in FIG. It can be configured to remotely control each of them via wired or wireless.

The display data of various characters, graphics, and the like, according to the control of the central control unit located at a remote location as described above, is a well-known wired or wireless communication method, and a plurality of all-optical display devices installed at the remote location from the central control device. Is transmitted to provide various guide information or advertisement contents.

However, since the conventional all-optical display device composed of a plurality of display modules each of which is arranged in a matrix form has only been configured in consideration of a display output function, when a malfunction occurs due to a failure of the display element, Other than the method of directly checking the output status of the all-optical display device, it is impossible to check the failure, and the failure state is left for a long time, which greatly impairs the reliability of information transmission, and also requires a lot of time and cost for maintenance. There was this.

Therefore, as a way to improve such a problem, a lot of efforts and proposals have been made in the past, as an example of the failure "in the light-emitting display device itself, which was published in Korean Patent Publication No. 95-6578 dated June 19, 1995 Diagnosis circuit " proposes a failure self-diagnosis circuit which detects the current value flowing through the all-optical display device and compares and judges it by the microcomputer control method so as to diagnose the failure of the display elements individually, in groups or as a whole.

As shown in FIG. 2, the fault diagnosis circuit attaches a current detection sensor to a power supply line supplied to an all-optical display device and detects the amount of current flowing through the power supply line. Analyze the number of faulty light emitting devices by comparing the required current value and the intensity of the current detected, and turn on and off the lights for multiple test patterns to identify the faulty light emitting devices. do.

However, since the conventional fault self-diagnosis circuit of FIG. 2 adopts a current detection method using electromagnetic induction, even if a failure occurs in the detection circuit, it does not affect the all-optical display device. Since the fault position can be detected only through a test mode that repeatedly performs the operation, the execution time of the test mode for determining the location of the failing element is unnecessarily long, and the original operation during the test mode is not necessary. There is a disadvantage that it does not perform any information output function, and also has a disadvantage that adversely affects the surrounding environment, such as unnecessary stimulation of the optic nerve of the driver traveling around the place where the corresponding light display device is installed.

In addition, as another way to improve the above-mentioned conventional problems, "open lamp for detection display lamp" is disclosed in the Korean Utility Model Publication No. 94-904 dated February 21, 1994, which is As shown in FIG. 3, the light emitting diode 221 of the photocoupler 220 is connected in series between the light emitting lamp 210 and the driving transistor 270 so that the lamp control output of the sign controller 230 is high. When the transistor 270 is turned on at a high level, the diode 221 of the photocoupler 220 emits light when the lamp 210 is turned on to turn on the photo transistor 222. The connection is configured to allow the lamp to be opened. That is, when the photocoupler 220 is turned off and the lamp open detection output D becomes high, it is determined that the lamp 210 is opened.

However, the lamp open detection circuit also has an advantage that the individual lamp 210 of the display board and the photocoupler for detecting the failure are connected in series, so that the failure location can be easily detected. When the photocoupler 220 itself malfunctions, the lamp that is normally operated is incorrectly opened. In addition, the light emitting diode 221 of the photocoupler 220 always interrupts the current to display the normal lamp 210. There is a fundamental problem that makes even impossible. In addition, in order to detect whether the lamp is open, each lamp must be turned on to check whether the lamp is opened. As in the case of FIG. 2, the disadvantage of not performing the original information output function at all during the test mode, and There is a disadvantage that adversely affects the surrounding environment, such as unnecessary stimulation of the optic nerve of the driver traveling around the place where the corresponding plate is installed.

The present invention proposed to solve the conventional problems as described above, it is possible to measure the failure of the display device without affecting the original operation of the display device, even if the display device is turned off It is an object of the present invention to provide a fault detection circuit of an all-optical display device capable of measuring.

1 is a schematic configuration diagram of a general all-optical display device;

2 is a diagram illustrating a failure detection circuit configuration of an all-optical display device according to the related art.

Figure 3 is an exemplary configuration of another fault detection circuit according to the prior art.

4 is a configuration diagram of an embodiment of a failure detection circuit of the all-optical display device according to the present invention;

5 is a flowchart illustrating an operation of checking a display state using an all-optical display circuit according to the present invention.

FIG. 6 is a detailed flowchart illustrating an exemplary embodiment of a display pattern checking operation of FIG. 5.

7A to 7E are exemplary diagrams of an expression pattern for explaining an expression state.

* Explanation of symbols for the main parts of the drawings

410: display unit 420: pixel driver

430: detector 431: voltage divider

433: comparison unit

The fault detection circuit of the present invention for achieving the above object is a fault detection circuit of an all-optical display device having a plurality of display elements, for driving the corresponding pixel of the all-optical display device according to a control signal input from the outside. Drive means; And detection means connected to the display element output terminal of the pixel in parallel with the driving means to detect a failure thereof without affecting the operation of the pixel.

In addition, the fault detection circuit of the present invention, the detection means, the voltage divider means for dividing the applied voltage connected between the output terminal of the display element and the ground at a predetermined ratio; And comparing means for comparing the voltage provided by the voltage dividing means with a predetermined reference voltage to determine whether the display element is in a failure state.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 4 to 6.

4 is a diagram illustrating an embodiment of a failure detection circuit of the all-optical display device according to the present invention. In the drawing, 410 is a display unit, 420 is a pixel driver, 430 is a detector, 431 is a voltage divider, and 432 is a comparator.

As shown in the figure, the failure detection circuit according to the present invention, the pixel driver 420 for driving the display unit 410 for forming the individual pixels in the all-optical display device according to a control signal input from the outside, The display unit 410 includes a detection unit 430 connected in parallel with the pixel driver 420 to detect whether a failure occurs without affecting the display operation of the pixel.

The detector 430 is again connected in parallel with the pixel driver 420 with respect to the display unit 410, and is connected between the display unit 410 and the ground to divide the applied voltage at a predetermined ratio. And a comparison unit 433 comparing the divided voltage provided by the voltage dividing unit 431 with a predetermined reference voltage to determine whether the display element is broken.

In addition, the display unit 410 is preferably provided with a power resistor (not shown) to suppress excessive current from flowing into the light emitting device.

In addition, the resistors R1 and R2 constituting the voltage divider 431 may employ a resistor having a very large resistance value so that a partial pressure applied to the resistor R2 may be detected while minimizing the flow of current. It can be configured by connecting resistors in series, or manually by connecting one resistor and one capacitor in series.

In a preferred embodiment of the present invention, when the power supply voltage (Vcc) is 24V, the operating current of the light emitting device of the display unit 410 is 60mA, the forward voltage is 18V, the resistance of the voltage divider 431 is 1MΩ By configuring the resistor to have a resistance value, the light emitting device of the display unit 410 is not turned on, so that the fixed detection can be performed even with only a slight current.

The comparator 433 inputs the voltage applied from the voltage divider 431 to the non-inverting input terminal, and inputs a reference voltage Vref set appropriately for fault detection to the inverting input terminal to differentially amplify and output the voltage. A differential amplifier (OP AMP) was used to perform the comparison function.

Now, look at the operation of the failure detection circuit according to the present invention.

First, the pixel driver 420 drives the display unit 410 according to a control signal input from the outside, so that the display unit 410 is turned on or off.

For example, when the display unit 410 is in a normal state when the control signal applied to the pixel driver 420 is high, the node N1 is turned low, and the node N2 and the detector 430 are low. All the nodes N3 also go low.

On the other hand, when the control signal is low, when the display unit 410 is normal, the display unit 410 is turned off while the node N1 becomes high, and both the nodes N2 and N3 of the detector 430 are also high. becomes high.

On the other hand, when the display unit 410 is disconnected, current cannot flow at all, regardless of the state of the control signal applied to the pixel driver 420 (even if the control signal is high). The display unit 410 is always turned off while the nodes N1, N2, and N3 are all low.

When the display unit 410 is short-circuited, when the control signal applied to the pixel driver 420 is high, the same operation as in the normal state is performed, but the control signal is low. ), The display unit 410 keeps the lighting state while the nodes N1, N2, and N3 are all low.

The detection unit 430 can detect whether there is a failure even when the display unit 410 is turned off without affecting its operation. The voltage dividing unit 431 is connected to the output terminal N of the display unit 410. The output voltage is distributed in proportion to the resistance values of the resistors R1 and R2, and a voltage applied to the resistor R2 (voltage of the node N2) is provided to the differential amplifier one input of the comparator 433. Then, the differential amplifier of the comparator 433 compares the input voltage with the reference voltage and outputs a failure determination signal of the display unit 410 to the output terminal N3.

That is, even when the display unit 410 is in a normal state, even if the display unit 410 is not driven because the voltage dividing unit 431 is low, the control signal applied to the pixel driver 420 is low. As the current paths through the resistors R1 and R2 of the device and the voltage divider 431 are formed and the micro current flows, the remaining voltage is obtained by subtracting the voltage drop amount due to the internal resistance of the display unit 410 from the power supply voltage Vcc. Since the resistors R1 and R2 of the voltage divider 431 are applied, a constant voltage divided by the node N2 is input to the comparator 433, and the comparison result is displayed as an output of the node N3. If the display unit 410 is disconnected, the node N2 will be OV since only a slight current does not flow through the voltage divider 431. As a result, when the output N3 of the comparator 433 is higher than or equal to a certain voltage, the display unit 410 is determined to be in a normal state, and if it is lower than or equal to a certain voltage, it is determined to be a faulty state. If it is low, it is determined as a failure state.

As described above, in the detector 430 of the device of the present invention, the voltage divider 430 flows to the light emitting element in the display 410 by allowing the resistors R1 and R2 of the voltage divider 431 to have a very large resistance value. By using a flow of a very small current (a current having a value smaller than the operating current, which is a conventional current), it is easy to determine whether the display unit 410 has a failure (disconnection) without affecting the display operation of the display unit 410. To be detected.

5 is a flowchart illustrating an operation of checking a display state using an all-optical display circuit according to the present invention.

As shown in the drawing, in the display state detection method of the all-in-one display device of the present invention, first, the microprocessor (see 'main control unit' of FIG. 1) provided in the all-in-one display device is inspected from an external (or remote) central control unit. Upon receiving the request signal (501), it is determined whether the received request is a request for checking for an abnormality of an individual dot or whether a request for checking content for actually monitoring the information content displayed on the screen of the electronic display (502). ). As a result of the determination, in the case of the individual dot check, the light-out control signal is outputted to the display unit section (see FIG. 1) (503).

Then, the display state data receiving processing unit receives the display state data, detects whether there is a malfunction due to a short circuit or disconnection, and stores the detected malfunction information (504). When the microprocessor is requested to output a display state from an external (or remote) central control device, the microprocessor reads and outputs the stored malfunctioning state information accordingly (505), and displays the normal original information. To be restored (506).

On the other hand, if the result of the check type determination 501 indicates that the display content check is required, the display content checking process as illustrated in FIG. 6 is performed (507). Referring to Figure 6 describes the display content checking process for monitoring the current display information as follows.

FIG. 6 is a detailed flowchart of an exemplary embodiment for explaining the expression checking operation 503, and FIGS. 7A to 7E are exemplary diagrams of an expression pattern for better understanding of an expression state.

First, a display control unit provided in each of the display modules of FIG. 1 outputs presentation information data (refer to a pattern intended to be represented in FIG. 7C) to a display unit unit so that image display is performed accordingly (601). The result (refer to the current detection pattern in Fig. 7A) is detected through the above-described failure detection circuit (602), hereinafter, the data representing the expression result is referred to as "expression pattern data".

Then, when the expression information data and the expression pattern data is compared with each other to determine whether an error occurs (603), if it is confirmed that an error has occurred, by performing the individual dot test as described above by the short circuit and disconnection A display error is detected (604) (see the individual dot error detection pattern in Fig. 7B). For reference, the " x " part of FIG. 7B shows a disconnection error part that is always turned off, and the " ☆ " part shows a short circuit error part that always maintains a lighting state.

Further, the current display state result (refer to the current display pattern of FIG. 7A) is input (605), and the pattern values of FIGS. 7B and 7C are subtracted from the pattern values of FIG. 7A, respectively (the pattern value of FIG. 7A − (Pattern Values in Figs. 7B + 7C), an error due to a short circuit is detected (606), and a short circuit error detection pattern value obtained immediately before is added to the pattern value in Fig. 7B to detect all error dots (607). .

The error check due to the short circuit is to check a situation in which output terminals of neighboring pixel drivers are shorted to each other so that at least two or more displays operate as one display unit. That is, when an output terminal of two or more pixel drivers is shorted, there is a state in which the driving state of one pixel driver affects the other display unit which is shorted.

Then, as shown in FIG. 7E, the error and normal data are separately displayed and returned (608). FIG. 7D, which is not described, shows a pattern that is actually displayed on an electric sign.

In addition, if the database management of the abnormality test results and repair results and the like through the present invention as described above, the history can be easily confirmed and efficient maintenance is possible.

The present invention described above is possible to those skilled in the art to which the present invention belongs, various substitutions, modifications and changes are possible within the scope without departing from the technical spirit of the present invention and the above-described embodiments and attached It is not limited to the drawings.

The present invention is constructed and operated as described above, so that even with a simple configuration, it is possible to simply check whether each display element is broken and its position without affecting the display device's natural information display operation in the light-off state. Thus, the reliability of the information display operation can be remarkably improved by eliminating the troublesome test mode (for example, a test mode using a special pattern such as a horizontal line, a vertical line, or an oblique line) to find a trouble spot. Since the component is composed of only semi-permanent components compared to the lifetime of the pixel display device, there is an effect of minimizing the occurrence of failure of the failure detection unit itself, thereby improving reliability of the failure detection operation.

In addition, it is possible to monitor the current display state as it is in real time from a remote location without directly looking at the all-optical display device, thereby improving the convenience of error correction and maintenance.

Claims (6)

In the fault detection circuit of an all-optical display device having a plurality of display elements, Driving means for driving a corresponding pixel of the all-optical display device according to a control signal input from the outside; And A detection means connected to the display element output terminal of the pixel in parallel with the driving means to detect whether there is a failure without affecting the operation of the pixel; Failure detection circuit of the all-optical display device comprising a. The method of claim 1, The detection means, Voltage dividing means connected to an output terminal of the display element and a ground to divide the applied voltage at a predetermined ratio; And Comparison means for comparing the voltage provided by the voltage dividing means with a predetermined reference voltage to determine whether the display element has failed; Failure detection circuit of the all-optical display device comprising a. The method of claim 2, The partial pressure means, A first resistor connected to an output terminal of the display element; And A second resistor connected between the first resistor and ground Failure detection circuit of the all-optical display device comprising a. The method of claim 2, The partial pressure means, A resistor connected to an output terminal of the display element; And And a capacitor coupled between the resistor and ground. The method of claim 3, wherein The comparison means, A non-inverting input terminal is connected between the first resistor and the second resistor, and an operational amplifier connected to apply a reference voltage to the inverting input terminal. Failure detection circuit of the all-optical display device comprising a. The method of claim 4, wherein The comparison means, A non-inverting input terminal is connected between the resistor and the capacitor, and an operational amplifier connected to apply a reference voltage to the inverting input terminal. Failure detection circuit of the all-optical display device comprising a.