JPH1159269A - Driving device for signal light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device for a signal light effective for detecting a broken core wire of a light-emitting-diode type signal light. SOLUTION: Signal lights 41-4N are composed of light-emitting diodes connected in series and in parallel. A drive element 1 is connected to the signal light 41 in series to turn on/off a current supplied to the signal light 41. The sensor 21 of a current detection circuit 2 is connected to the signal light 41 in series to detect a current supplied to the signal light 41 and to output a current detection signal S1. A level detection circuit 22 detects the level of the current detection signal S1 supplied by the sensor 21 to output a level detection signal S2. A signal processing part 7 judges the presence or absence of failure of the drive element 1 and the signal light 41 by means of the logic of drive signals S31, S32 and the level detection signal S2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a signal lamp driving device.

[0002]

2. Description of the Related Art A driving device used for driving various signal lamps has a fail-safe function for controlling the signal lamps to a safe side when a failure of a driving element is detected, or a standby dual system. A function of switching to a standby system when a failure of the drive element is detected is provided. As the prior art, the techniques disclosed in JP-A-4-76467, JP-A-4-70570, JP-A-9-101336 and the like are known.

[0003] The techniques described in these known technical documents are aimed at driving an incandescent lamp type signal lamp and detecting a disconnection failure. However, recently, instead of the incandescent lamp-type signal lamp, a light-emitting diode-type signal lamp in which longer-life light-emitting diodes are connected in series and parallel has been used. In the case of a light-emitting diode type signal lamp, unlike the incandescent lamp type signal lamp, all of the light-emitting diodes do not simultaneously cause a core breakage. Therefore, even if the core breakage occurs, the current does not significantly increase or decrease. Therefore, the above-described known technique for driving an incandescent lamp type signal lamp and detecting a disconnection failure cannot be used as it is for a light emitting diode type signal lamp.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a signal lamp driving device which is effective for detecting a disconnection of a light emitting diode type signal lamp.

Another object of the present invention is to provide a signal lamp driving device capable of completely extinguishing a light emitting diode type signal lamp to be extinguished when displaying multiple indications with the light emitting diode type signal lamp. It is.

Another object of the present invention is to provide a signal lamp driving device capable of finely adjusting the setting of the disconnection state of the signal lamp by software processing.

[0007]

In order to solve the above-mentioned problems, a signal lamp driving device according to the present invention includes a signal lamp, a driving element, a current detection circuit, and a signal processing unit. The signal lamp is configured by connecting a large number of light emitting diodes in series and parallel. The driving element is connected in series to the signal lamp and turns on / off a current supplied to the signal lamp.

[0008] The current detection circuit includes a sensor and a level detection circuit. The sensor is connected in series with the signal lamp, detects a current supplied to the signal lamp, and outputs a current detection signal. The level detection circuit tests a level value of a current detection signal supplied from the sensor and outputs a level detection signal.

The signal processing section supplies a drive signal to the drive element to perform an on / off operation, and determines whether the drive element and the signal lamp have a failure based on a logic of the drive signal and the level detection signal. judge.

As described above, the signal processing section supplies a drive signal to the drive element to perform an on / off operation. The drive element is connected in series to the signal lamp, and turns on / off a current supplied to the signal lamp based on a drive signal supplied from the signal processing unit. The sensor of the current detection circuit is connected in series to the signal lamp, detects a current flowing through the signal lamp, and outputs a current detection signal. Thus, when the drive element is in the on state, a current detection signal corresponding to the current supplied to the signal lamp is obtained, and when the drive element is in the off state, a current detection signal without the signal lamp current is obtained. .

The level detection circuit of the current detection circuit verifies the level value of the current detection signal supplied from the sensor and outputs a level detection signal. When the signal lamp is normal, the level of the current detection signal supplied from the sensor is above a certain level. On the other hand, when an open failure occurs in the light emitting diode constituting the signal lamp, the level of the current detection signal supplied from the sensor is lower than the normal level. The level detection circuit outputs a level detection signal corresponding to the level.

The signal processing unit determines whether or not the drive element and the signal lamp have a failure based on the logic of the drive signal and the level detection signal. For example, when the drive signal is a signal having a logical value of 1 for turning on the drive element and the level detection signal is at a level corresponding to the normal operation of the signal lamp, both the drive element and the signal lamp are normal. It is determined that there is. When the drive signal is a signal having a logical value of 1 to turn on the drive element, the level detection signal is at a low level corresponding to a case where an open failure has occurred in at least a part of the light emitting diodes included in the signal lamp. When the drive element is normal,
It is determined that the signal light has failed.

Whether the drive element or the signal lamp is out of order can be determined by examining the level of the current detection signal using a level detection circuit. That is, since the signal light device is configured by connecting a large number of light emitting diodes in series and parallel, no open failure occurs in all the light emitting diodes of the signal light device at the same time. On the other hand, when an open failure occurs in the drive element, the level of the current detection signal drops at a stretch. Since the level detection circuit outputs a level detection signal corresponding to the level of the above-described current detection signal, the signal processing unit determines which of the driving element and the signal lamp is to be operated based on a difference in the level of the current detection signal indicated by the level detection signal. Can be identified as having failed. Therefore, it is possible to obtain a signal lamp driving device effective for detecting the disconnection of the light emitting diode type signal lamp.

In addition, the level detection signal output from the level detection circuit is input to a signal processing unit which can be constituted by a computer to determine whether or not the drive element and the signal lamp have a failure. Can be set by software processing. Therefore, the setting of the disconnection state of the signal lamp can be finely adjusted.

In the case where multiple indications are displayed by the light emitting diode type signal lamps, the driving element and the current detection circuit can be constituted independently of each other for each indication signal lamp. A signal lamp driving device capable of completely extinguishing a signal lamp can be realized.

The signal lamp driving device according to the present invention preferably includes a checking circuit. The checking circuit monitors the current detecting circuit. Specifically, a switch element is connected to a third winding provided in a current transformer constituting the current detection circuit. The signal processing unit supplies a check signal for turning on / off a switch element included in the checking circuit to the checking circuit. Then, the quality of the current detection circuit is determined by detecting the presence or absence of the current detection signal supplied from the current transformer based on the level detection signal output from the level detection circuit. By employing such a circuit configuration, it is possible to avoid an erroneous determination caused only by a failure of the current detection circuit irrelevant to the failure of the drive element and the signal lamp.

The other features of the present invention and the operation and effects thereby will be described in more detail with reference to the accompanying drawings.

[0018]

FIG. 1 is a block diagram showing a configuration of a signal lamp driving device according to the present invention. The signal light driving device according to the present invention includes a signal light 41 to 4N and a driving element 1
And a current detection circuit 2 and a signal processing unit 7. The power supply (+) is a hot-side AC power supply terminal, and the power supply (-) is a negative-side AC power supply terminal.

The signal lamps 41 to 4N are configured by connecting a large number of light emitting diodes D11 to Dnm in series and parallel.
The signal lights 41 to 4N are provided in a number N corresponding to the present number. Also, circuits C1 to CN including the driving element 1 and the current detection circuit 2 are provided by the present number n. Circuit C1
Since CN has substantially the same configuration, and the signal lamps 41 to 4N have substantially the same configuration, the circuit elements included in the circuit C1 and the signal lamp 41 driven by the circuit C1 will be representatively described below. I do.

FIG. 2 is an electric circuit diagram showing an example of the signal lamp 41, which is constituted by connecting a large number of light emitting diodes D11 to Dnm in series and parallel. R1 to Rn are current limiting resistors.

The driving element 1 is connected in series to the signal lamp 41 and turns on / off the current supplied to the signal lamp 41.
The driving element 1 is a solid state relay (hereinafter, SS)
Called R. ) Etc. Driving element 1 shown
Is configured by connecting switch elements 11 and 12 made of SSR in series.

The current detection circuit 2 includes a sensor 21 and a level detection circuit 22. The sensor 21 is connected in series to the signal lamp 41, detects a current supplied to the signal lamp 41, and outputs a current detection signal. The illustrated sensor 21 comprises:
It consists of a current transformer. The current transformer includes a first winding N1 and a second winding N2. The first winding N1 is connected in series to the signal lamp 41, and the second winding N
2 outputs a current detection signal S1.

The level detection circuit 22 tests the level value of the current detection signal S1 supplied from the sensor 21 and outputs a level detection signal S2. The illustrated level detection circuit 22
Is configured by sequentially and cascade connecting a bandpass filter 221, an amplifier 222, and a rectifier circuit 223. However, it is not limited to such a circuit configuration.

The signal processing section 7 supplies a driving signal S to the driving element 1.
31 and S32 are supplied to perform an on / off operation, and the logic of the drive signals S31 and S32 and the level detection signal S2 determines whether or not the drive element 1 and the signal lamp 41 are faulty.
The signal processing unit 74 can be constituted by a microcomputer. The drive signals S31 and S32 are supplied to the drive element 1 through an I / O bus.

In the embodiment, the level detection signal S2 of the level detection circuit 22 is supplied to an analog / digital converter (hereinafter, referred to as an A / D converter) 6 via a multiplexer 5. The level detection signal S2 is an analog signal, and is converted from an analog signal to a digital signal in the A / D converter 6 and supplied to the signal processing unit 7 via the I / O bus.

As described above, the signal processing unit 7 supplies the drive signals S31 and S32 to the drive element 1 to perform an on / off operation. The driving element 1 is connected in series to the signal lamp 41, and the driving signals S31 and S3 supplied from the signal processing unit 7
2, the current supplied to the signal lamp 41 is turned on / off.
Turn off. The sensor 21 of the current detection circuit 2
1 is connected in series, and detects a current flowing through the signal lamp 41, and outputs a current detection signal S1. According to this configuration,
When the driving element 1 is in the on state, a current detection signal S1 corresponding to the current supplied to the signal lamp 41 is obtained. When the driving element 1 is in the off state, the current detection signal S1 without the signal lamp current is generated. can get.

The level detection circuit 22 of the current detection circuit 2
The level value of the current detection signal S1 supplied from the sensor 21 is verified to output a level detection signal S2. Signal light 4
When 1 is normal, the level of the current detection signal S1 supplied from the sensor 21 is higher than a certain level. On the other hand, the light-emitting diode D11
When an open fault occurs in Dnm to ｎｍDnm, the level of the current detection signal S1 supplied from the sensor 21 becomes lower than the normal level. The level detection circuit 22 outputs a level detection signal S2 corresponding to the above level.

The signal processing section 7 comprises drive signals S31, S32
It is determined whether or not the drive element 1 and the signal lamp 41 are faulty based on the logic of the signal and the level detection signal S2. For example, when the drive signals S31 and S32 are signals of a logical value 1 for turning on the drive element 1, the level detection signal S2 is
Is at a level corresponding to the normal operation of the driving element 1
And it is determined that both the signal lamp 41 are normal. When the drive signals S31 and S32 are signals of the logical value 1 for turning on the drive element 1, the level detection signal S2 causes an open failure in at least a part of the light emitting diodes D11 to Dnm included in the signal lamp 41. When it is at the low level corresponding to the case where it is determined that the driving element 1 is normal, the signal lamp 41 is out of order.

Whether the drive element 1 or the signal lamp 41 has failed can be determined by examining the level of the current detection signal S1 with the level detection circuit 22. That is, since the signal light device 41 is configured by connecting a large number of light emitting diodes D11 to Dnm in series and parallel, no open failure occurs in all the light emitting diodes D11 to Dnm of the signal light device 41 at the same time. On the other hand, when an open failure occurs in the driving element 1, the level of the current detection signal S1 becomes near zero level at a stretch. Since the level detection circuit 22 outputs the level detection signal S2 corresponding to the level of the above-described current detection signal S1, the signal processing unit 7 performs the driving based on the level difference of the current detection signal S1 indicated by the level detection signal S2. Which of the element 1 and the signal lamp 41 is out of order can be specified. Accordingly, it is possible to obtain a signal lamp driving device effective for detecting the disconnection of the light emitting diode type signal lamp 41.

Further, the level detection signal S2 output from the level detection circuit 22 is input to the signal processing section 7 which can be constituted by a computer, and the presence or absence of a failure of the drive element 1 and the signal lamp 41 is determined. Thus, the failure determination criteria can be set by software processing. For this reason,
The setting of the decentered state of the signal light 41 can be finely adjusted.
The same applies to the other signal lights 42 to 4N.

Further, light emitting diode type signal lights 41 to 4
N, when displaying multiple indications by a method of connecting the two lights in series and lighting them, etc., each indication signal light 41
4N, the driving element 1 and the current detection circuit 2 can be configured independently of each other, so that among the light emitting diode type signal lamps 41 to 42, the light emitting diode type signal lamps to be turned off are completely extinguished. I can make it.

In the embodiment, a checking circuit 3 is further included. The checking circuit 3 monitors the current detecting circuit 2. In particular,
A switch element 31 is connected to a third winding N3 provided in a current transformer constituting the sensor 21. The signal processing unit 7 periodically supplies a check signal S4 for turning on / off the switch element 31 included in the checking circuit 3 to the checking circuit 3. According to the check signal S4,
When the switch element 31 is turned on, the third winding N3
The current transformer that forms the sensor 21 is excited by the current flowing through the second winding N2, and the current detection signal S
1 results.

The quality of the current detection circuit 2 is determined by detecting the presence or absence of the current detection signal S1 supplied from the sensor 21 based on the level detection signal S2 output from the level detection circuit 22. By employing such a circuit configuration, it is possible to avoid an erroneous determination that is not related to the failure of the driving element 1 and the signal lamp 41 and is caused only by the failure of the current detection circuit 2. At the time of checking of the current detection circuit 2, the drive signals S31 and S3
Since there is no supply of 2, no current flows through the signal lamp 41. Therefore, the signal lamp 41 does not light up.

[0034]

As described above, according to the present invention, the following effects can be obtained. (A) It is possible to provide a signal lamp driving device that is effective for detecting a disconnection of a light emitting diode type signal lamp. (B) It is possible to provide a signal lamp driving device capable of completely extinguishing a light emitting diode type signal lamp to be extinguished when displaying multiple indications by a light emitting diode type signal lamp. (C) It is possible to provide a signal lamp driving device capable of finely adjusting the setting of the disconnection state of the signal lamp by software processing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a signal lamp driving device according to the present invention.

FIG. 2 is a diagram illustrating a circuit example of a signal lamp used in the signal lamp driving device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive element 2 Current detection circuit 41-4N Signal lamp 7 Signal processing part

Claims (4)

[Claims] 1. A signal lamp driving device including a signal lamp, a driving element, a current detection circuit, and a signal processing unit, wherein the signal lamp is configured by connecting a large number of light emitting diodes in series and parallel. The driving element is connected in series to the signal lamp, and turns on / off a current supplied to the signal lamp. The current detection circuit includes a sensor and a level detection circuit. The level detection circuit is connected in series with the signal lamp, detects a current supplied to the signal lamp and outputs a current detection signal, and the level detection circuit verifies a level value of the current detection signal supplied from the sensor to determine a level. The signal processing unit supplies a drive signal to the drive element to perform an on / off operation, and outputs a detection signal according to a logic of the drive signal and the level detection signal. Signal lamp driving device that determines the presence or absence of a fault. 2. The signal lamp driving device according to claim 1, wherein the sensor is a current transformer, wherein the current transformer includes a first winding and a second winding, The signal lamp driving device, wherein the first winding is connected in series to the signal lamp, and the second winding outputs the current detection signal. 3. The signal lamp driving device according to claim 2, further comprising an inspection circuit, wherein the inspection circuit is a circuit for monitoring the current detection circuit, and is provided in the current transformer. A switch element is connected to the third winding, and the signal processing unit supplies a check signal for turning on / off the switch element to the checking circuit, and determines whether the current detection signal is present. A signal lamp driving device that determines the quality of a current detection circuit. 4. The signal lamp driving device according to claim 1, wherein the driving element includes two switch elements connected in series.