JPH01321380A - Drive circuit - Google Patents

Abstract

PURPOSE:To enable handy automatic discovery of disruption of an LED element and a non-continuity between driven devices by accomplishing electric judgement of condition on the output terminal side between forcible turning OFFs of a signal output to an open collector by a scanning pulse. CONSTITUTION:When receiving a signal on the input terminal side, a drive means 10 outputs the signal with an open collector on the output terminal side to access a corresponding driven device 50. Then, an output of the open collector is forcibly turned OFF at a predetermined time interval by a scanning pulse outputted from a scanning pulse generation means 20. The state on the output terminal side during the period is judged electrically by a judging means 30 to determine continuity and disconnection with the device 50. This enables handy and automatic testing during the operation.

Description

[Detailed Description of the Invention] (Summary) Regarding a drive circuit that receives an input signal and outputs a signal through an open collector to access the corresponding driven device, many LED elements are burnt out and connections between the driven devices are broken. Our goal is to provide a drive circuit with a function that allows you to easily and automatically detect failures such as failures due to disconnection or disconnection of connectors. Electrically determines the state of the output terminal side while forcibly turning off the signal output to the open collector using the scanning pulse generation means that generates the pulse and the scanning pulse output from the scanning pulse generation means. The device is configured to include a determining means for determining the conduction state or disconnection state with the driven device.

[Industrial application field]

The present invention relates to a drive circuit that receives an input signal and outputs a signal through an open collector to access a corresponding driven device.

For example, in order to access a device such as a display device that uses a large number of display elements such as lamps, a drive circuit with an open collector output is often used.

The display elements used in such display devices can perform a predetermined function by lighting up.
However, the lighting time has a certain lifespan, and when the lifespan has been reached, it is necessary to detect it early and take measures such as replacing it.

[Conventional technology]

FIG. 9 shows a block diagram illustrating a conventional example.

The diagram shown in FIG. 9 shows a conventional example of a drive circuit 1 for an access device 3 to access a driven device 4. As shown in FIG.

This drive circuit 1 receives an input signal and outputs a signal using an open collector to access the driven device 4. For example, the driven device 4 is a display device having a large number of display elements.

Therefore, for example, a plurality of drive circuits 1 are generally installed to drive one or more display elements (for example, light emitting diodes, hereinafter referred to as LEDs).

The conventional drive circuit 1 shown in FIG.
For example, if you want to inspect the display failure of a large number of LED elements used in the driven device 4 or the connection status between the drive circuit 1 and the driven device 4 by accessing only the There is a need.

For example, a large number of LED elements used in the driven device 4, which is a display device, may break out from time to time.
The following method is used to discover this broken ball.

That is, a method in which all LED elements are forcibly turned on at once by operating a specially provided switch, and it is visually determined whether the LED elements are lit or not (commonly known as a lamp test).
.

Next, for example, the connection between the drive circuit 1 and the driven device 4 is made by a cable (a) connection using a connector 2 (consisting of a plug 2a and a jack 2b) as shown in FIG. 9, or by wrapping or wrapping a terminal. When the wire (b) is connected by soldering, it is conceivable that the connected portion may become non-conductive due to an unexpected cause (for example, wire breakage or disconnection of the connector).

In such a case, the driven device 4 malfunctions, and as a result, it is not until the driven device 4 is investigated that it is discovered that the connected portion is disconnected due to an unexpected cause (for example, a disconnection or disconnection of a connector). Ru.

[Problem to be solved by the invention]

As mentioned above, when using the drive circuit 1 shown in FIG.
Whether or not the ED element is lit may not be discovered until a lamp test is performed.

Furthermore, in a case where a large number of LED elements are randomly arranged (for example, in a large map graphic panel), there is a possibility that a bulb burnout may be overlooked during a lamp test.

Furthermore, in order to light up a large number of LED elements at once, a large amount of electric power is required, and a large amount of electric power is consumed for each lamp test.

On the other hand, even if there is a disconnection between the drive circuit 1 and the driven device 4 due to disconnection or disconnection of the connector, the driven device 4
The discontinuity is discovered only after a malfunction occurs, and in the case of a driven device 4 that cannot tolerate instantaneous interruption, the discontinuity causes great damage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a drive circuit that has a function that allows troubles such as broken bulbs of a large number of LED elements, broken connections between driven devices, and disconnected connectors to be detected easily and automatically in advance. .

[Means to solve the problem] FIG. 1 shows a block diagram illustrating the invention in detail.

In the block diagram of the principle of the present invention shown in FIG. 1, 20 is a scanning pulse generating means that generates a pulse that forcibly turns off the output of the open collector at predetermined time intervals, and 30 is a scanning pulse generating means. By electrically determining the state of the output terminal while the signal output to the open collector is forcibly turned off by the scanning pulse generated from the means 20, the conduction state or disconnection state with the driven device 50 is determined. This is a determination means for determining, and by providing such a means, it is a means for solving this problem.

[For production]

The open collector of the output stage of the drive means 10 that drives the target driven device 50 is forcibly cut off during the output of a constant period pulse from the scanning pulse generation means 20, and is driven regardless of the presence or absence of an input signal. Comparing the voltage state on the output side of the means lO by the determining means 20,
By automatically testing the lamps and attached wires mounted on the driven device 50 during operation, it becomes possible to easily and automatically test for bulb burnout of lamps, disconnection of attached wires, etc.

〔Example〕

The gist of the present invention will be specifically explained below with reference to embodiments shown in FIGS. 2 to 8.

4 is a diagram illustrating the configuration of one block of the lamp drive unit in an embodiment of the present invention. FIG. 5 is a diagram illustrating an embodiment of the determination circuit in the present invention. FIG. 6 is a diagram for explaining an example of pulse scanning and lamp display in an embodiment of the present invention, FIG. 7 is a diagram for explaining an embodiment of a pulse scanning unit in the present invention, and FIG. 8 is a diagram for explaining an example of a pulse scanning unit in an embodiment of the present invention. Figures illustrating examples of ball outage state determination are shown. Note that the same reference numerals indicate the same objects throughout the figures.

Incidentally, as the drive means 10 explained in FIG. 1, two transistors Trl are used as shown in FIG.

2, resistors R1 to R4, and a lamp drive unit 101(i) consisting of a diode Di as a basic unit,
The lamp drive block 10a(i) is composed of a plurality of lamp drive units 101(i), and the scanning pulse generating means 20 is a 4-bit binary counter 203 as shown in FIG.
and a plurality of pulse scanning units 20 whose basic unit is the decoder 204! (i) As shown in FIG. 5, the pulse scanning circuit 20 is composed of a pulse scanning circuit 20, and the determining means 30 includes a NAND circuit (hereinafter referred to as a NAND circuit) 301 that takes the NAND of a plurality of out-of-ball detection signals, and a clock. This is an example in which the judgment circuit 30a includes a logical product circuit (hereinafter referred to as an AND circuit) 302 that calculates the logical product of the pulse and the output of the NAND circuit 301.

The embodiment of the present invention automatically inspects for burnout of a large number of indicator lamps while in operation, and does not require manual operation or special operation by taking the driven device 4 offline as shown in FIG. It is possible to detect a broken ball without the need for

FIG. 2 shows the overall structure of a drive section that drives a driven device 4 having a large number of lamps.

Now, if the number of indicator lamps (for example, LEDs) mounted on the driven device 4 is 48 (=16x3), the lamp drive units 101(1) to 101(16) shown in FIG.
) is configured by connecting 16 lamp drive blocks 10a (1) to 10a (3).

Incidentally, the lamp (LP) number display circuit 40 displays the bulb burnout number based on the LP number information in each lamp drive block 10a(1) to 10a(3), the block address information, and the bulb burnout notification signal output from the determination circuit 30a. The number display 4
It can be displayed on 0a.

Further, the pulse scanning unit 201(i) in the pulse scanning circuit 2Oa sends a pulse for bulb burnout detection to each corresponding lamp drive unit 101(i).

The lamp drive unit 101(i) shown in FIG.
When the pulse scanning circuit 20a manually generates a pulse for detecting bulb breakage, even if there is an LP drive input, the third
Since Tr2 shown in the figure turns on, Tri is male and the power supply ■
The high resistance (R3+R4) and LP become a circuit connected in series between and 30.

At this time, the voltage level at point X becomes the resistance division ratio of the LP resistor +R3 and R4, and becomes an H level input to the determination circuit 30a. Therefore, when the LP resistor is in an OFF state, the voltage level at point X becomes the same as SG, so that the L level is input to the determination circuit 30a.

As shown in FIG. 5, the determination circuit 30a determines the L level as NA.
The ND circuit 301 performs NAND, and the result and the clock pulse synchronized with the bulb burnout detection pulse are ANDed in the AND circuit 3.
02, and a bulb out notification signal is sent to the LP number display circuit 40 as shown in FIG.

The pulse scanning circuit 20a that generates pulses for ball breakage detection is composed of three pulse scanning units 201(1) to 201(3) as shown in FIG. This is based on what is generated from the oscillator 202 that is being used.

That is, pulses generated from the oscillator 202 are counted by a 4-bit binary counter 203 shown in FIG. 7, and decoded into 16-bit pulses by a decoder 204.

When this 16-bit pulse is sent to the 16 lamp drive units 101(1) to 101(16), the 4-bit binary counter 203 outputs a carryout Co, and the next pulse scanning unit 201(1)
) to 201(3).

In this way, all lamp drive blocks 10a
Detection pulses scanned bit by bit are sent to (1) to 10a(3).

At this time, each pulse scanning unit 201 (1
) to 201(3) (in this embodiment, it is a 4-bit binary code, and is counted by the focus counter 401 in the LP display circuit 40) and the block address information (in this embodiment, it is a bit The block counter 4 in the LP display circuit 40
The LP number is determined from the 2 information G (counted at 02).

When a ball outage is detected, the ball outage notification signal from the determination circuit 30a is used as a selection signal for the selector 403, and the ball outage LP number is displayed on the numerical display 40a.

FIG. 8 shows a summary of the correspondences such as the out-of-ball detection pulse and the LP status 2-output notification signal depending on the presence or absence of the LP drive input as described above.

That is, for example, in a normal state, if there is no LP drive input, there will be no bulb breakage notification signal even if there is a bulb burnout detection pulse, and if the bulb burns out and there is an LP drive input, there will be a bulb burnout detection pulse, and point It becomes L level and there is a ball out notification signal.

Note that each pulse scanning unit 201(1) to 201(1) to 2
The bulb breakage detection pulse sent from 01(3) has a pulse width of about 100m5, so even if the bulb burnout detection pulse is input and the LP goes out when there is an LP drive input, it will not turn on with the naked eye. Since it can be seen as it is, there is no problem in operation.

〔Effect of the invention〕

According to the present invention as described above, it is possible to automatically check for burnt out bulbs in a large number of indicator lamps without requiring any manual operation or taking the device off-line and performing any special operations while in operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram explaining the present invention in detail, and a diagram explaining the added lamp drive unit. FIG. 4 is a diagram explaining the configuration of one block of the lamp drive unit in an embodiment of the present invention. FIG. 6 is a diagram illustrating an example of pulse scanning and lamp display in an embodiment of the present invention. FIG. 7 is a diagram illustrating an embodiment of a pulse scanning unit in the present invention. FIG. 8 is a diagram illustrating an example of determining the out-of-ball state in an embodiment of the present invention, and FIG. 9 is a block diagram illustrating a conventional example. In the figure, l is the drive circuit, 2 is the connector, 2a is the plug, 2b is the jack, 3 is the access device,
4 is a driven device, IO is a drive means, 10a (1) to lOa (3) are lamp drive blocks, 20 is a scanning pulse generation means, 20a is a pulse scanning circuit, 30 is a determination means, 30a is a determination circuit, 40 is L
P number display circuit, 40a is number display, 101 (1)
~101(16), 101(i) are lamp drive units, 201(1) to 201(3), 20Hi) are pulse scanning units, 202 is an oscillator, 203 is a 4-bit binary counter, 204 is a decoder, 301 is a NANO circuit, 3
02 is an AND circuit, 401 is a focus counter,
402 is a block counter, 403 is a selector, and +v is a detailed block diagram of the present invention. 2.5
Figure Ochin and BF4 1 Aropulsus〒Yanni〉7 Unizuto's Tribute 1 Example Execution 1 vs. Otsu No. 7 Figure ゛! Figure 9 is a block diagram explaining a conventional example.

Claims (1)

[Claims] When a signal is received on the input terminal side, the signal is outputted by an open collector on the output terminal side and the corresponding driven device (
50), comprising a scanning pulse generating means (20) for generating a scanning pulse for forcibly turning off the output of the open collector at predetermined time intervals; , by electrically determining the state of the output terminal while the signal output to the open collector is forcibly turned off by the scanning pulse output from the scanning pulse generating means (20); Drive device (
determination means (3) for determining the conduction state or disconnection state with
0).