JP3121236B2 - LED beacon light system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED marker light and the LE
The present invention relates to an LED marker light system including a control unit for controlling the light emission of the D marker lamp, and a line (electric connection path) connected between them, and has various meanings in various applications such as railroads and roads. It can be used to indicate content.

[0002]

2. Description of the Related Art Since an LED marker light system indicates various meanings (for example, an emergency warning or a traffic signal), it must be operated reliably. However, the LED marker light is often installed at a position distant from the control unit.
There is a possibility that the line connecting the ED marker lamp and the control unit is disconnected. In this case, even if the LED marker lamp is caused to emit light, the light cannot be emitted, and the predetermined meaning cannot be transmitted. Therefore, in the LED marker light system, in order to enhance the reliability, it is required to monitor the connection state of the line and automatically detect a disconnection or the like of the line.

[0003] By the way, when detecting such a disconnection of the line, if the LED marker light is made to emit light even when it is not time to transmit a predetermined meaning (for example, at the time of an alarm), even if the light is emitted, Even if the time is short, there is a possibility that the meaning may be erroneously recognized as being transmitted, which is not preferable.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been made without any fear of misidentification of a sign.
An object of the present invention is to provide an LED marker light system capable of detecting disconnection of a line between an ED marker lamp and a control unit.

[0005]

In order to achieve the above object, an LED marker light system according to a first aspect of the present invention has one or more LEDs and first and second connection parts, An LED marker light in which the one or more LEDs emit light only when a voltage equal to or higher than a predetermined level is applied between the first and second connection portions; and a first and second connection portion of the LED marker light. A control unit connected via a line (electrical connection path) to control light emission of the LED marker light,
A control unit having switching means for turning on and off in response to a light emission control signal, wherein the LED indicator light and the switching means are connected in series to a DC power supply;
A first resistor connected between the first and second connection parts on the side of the ED marker lamp, and a switching element connected in parallel with the switching means on the control part side; Circuit means for forming a current path in the state and limiting a voltage between the first and second connection portions of the LED indicator lamp to a level lower than the predetermined level; First current detecting means for detecting whether or not a current of a predetermined level or more is flowing.

[0006] The LED beacon light system according to a second aspect of the present invention is the LED beacon light system according to the first aspect, wherein the circuit means has a current equal to or greater than a second predetermined level greater than the first predetermined level. A second current detecting means for detecting whether or not the current is flowing is further provided.

The first and second current detecting means indirectly detect whether or not a voltage of a predetermined level or higher is applied to a predetermined portion of the circuit means. It may detect whether or not a current equal to or higher than the first or second predetermined level is flowing.

[0008] The first and second current detecting means may constitute a part of the circuit means.

[0009]

According to the LED marker light system according to the first and second aspects, the LED marker lamp and the switching means of the control section are connected in series to the DC power supply,
A first resistor is connected between the first and second connection portions of the LED marker light on the side of the marker lamp, and the circuit means is connected in parallel with the switching means.

Therefore, when the switching means is in the off state (ie, when the LED indicator light is not to emit light), if the line between the LED indicator light and the control unit is not broken, the line , A current flows from the DC power supply via the first resistor and the circuit means. At this time, the circuit means limits the voltage between the first and second connection portions of the LED marker light to a level lower than a level necessary for causing the LED marker lamp to emit light. No, therefore, there is no risk of misidentification of the sign. On the other hand, when the line between the LED indicator light and the control unit is disconnected while the switching means is in the off state, no current flows through the circuit means.

For this reason, the first predetermined level, which is a current detection reference for the first current detecting means, is set to a current flowing through the circuit means when the line is not disconnected when the switching means is off. When the switching means is in the OFF state, a signal indicating whether or not the line is disconnected is obtained from the first current detecting means.

By the way, when the switching means is in the ON state (ie, when the LED indicator lamp is about to emit light), the switching means is in a state where both ends of the circuit means are short-circuited. Does not work, and if the line is not broken, a voltage higher than the level required to make the LED marker light emit between the first and second connection portions of the LED marker lamp is applied,
The beacon lights up.

Note that the LEs according to the first and second aspects are used.
According to the D-marking lamp system, when the switching means is in the ON state, no current always flows through the circuit means regardless of whether or not the circuit is disconnected. Can not do it. However, in the LED beacon system, the period during which the LED beacon is not lit is usually much longer than the period during which the LED beacon is lit, so that there is no practical problem.

As described above, according to the LED marker lamp systems according to the first and second aspects, the disconnection of the line between the LED marker lamp and the control unit is detected without fear of misidentification of the marker. be able to.

Further, according to the LED marker light system according to the second aspect, it is possible to detect whether or not a current of at least a second predetermined level larger than the first predetermined level is flowing through the circuit means. Since the current detecting means is further provided, not only the disconnection of the line but also the short circuit of the line can be detected.

That is, when the switching means is in the off state, when the line is short-circuited, the voltage applied to the circuit means is smaller than when the line is normal (when the line is neither disconnected nor short-circuited). And the level of the current flowing through the circuit means is higher than when the line is normal. Therefore, the second predetermined level, which is a current detection reference for the second current detection means, is set to be higher than the level of the current flowing through the circuit means when the line is normal when the switching means is off. In addition, by setting the level of the current flowing through the circuit means to be lower than the level of the current flowing through the circuit means when the switching means is in the off state, the second current is supplied when the switching means is in the off state. A signal indicating whether the line is short-circuited is obtained from the detecting means.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an LED marker light system according to an embodiment of the present invention will be described with reference to FIG. FIG.
It is a circuit diagram showing the LED marker light system according to the present embodiment.

The LED marker light system according to the present embodiment
As shown in FIG. 1, an LED marker light 1 and a control unit 2 such as a control panel for controlling light emission of the LED marker light 1 are provided.

The LED marker light 1 includes a plurality of LEDs 3 and 2
The plurality of LEs are provided only when a voltage equal to or higher than a predetermined level _VST is applied between the connection portions A and B.
D3 emits light. As described above, the LED 3 emits light only when a voltage equal to or higher than the predetermined level V _ST is applied between the connection portions A and B because the LED 3 emits no current unless a forward voltage equal to or higher than the predetermined level is applied. This is due to the fact that it does not emit light.

In this embodiment, the LED marker lamp 1 has a configuration in which a plurality of LED rows 4 are connected in parallel between the connecting portions A and B. Each of the plurality of LED rows 4 includes a plurality of LEDs 3
And the current limiting resistor 5 is connected in series. The anode side of the LED string 4 is connected to the connection part A,
The cathode side of the ED row 4 is connected to the connection part B. In this embodiment, since the LED marker light 1 has a plurality of LEDs 3, the display area can be increased. However, in the present invention, the LED marker light 1 only needs to have at least one LED. . Further, in this embodiment, it is possible to arbitrarily set the predetermined level V _ST by the number of LED3 of the LED column 4.

The control section 2 has connection sections C and D. The connection sections C and A are connected by a line 6, and the connection sections D and B are connected by a line 7. Although not shown in the drawings, the lines 6 and 7 are electrical connection paths that include not only wiring such as cables but also terminals and connectors as necessary.
Further, the control unit 2 has a DC power supply (not directly shown in the figure, V _CC in the figure shows a power supply line connected to the positive electrode of the DC power supply, and ground in the figure shows a power supply line connected to the negative electrode of the DC power supply. A ground line (shown as a zero volt line) connected thereto, a switching FET 8 as switching means for turning on / off in response to a light emission control signal, and a circuit (not shown) for generating the light emission control signal; have. The light emission control signal is input to the gate of the FET 8. The switching means is not limited to an FET, and various other switching elements and relay contacts can be used.

An LED indicator light 1 and an FET 8 are connected in series to the DC power supply. That is, in this embodiment, the connection portion C is connected to the power supply line V _CC , the connection portion D is connected to the drain of the FET 8, and the source of the FET 8 is connected to the ground line (grounded).
However, instead of connecting in this way, for example, FE
By connecting the drain of T8 to the power supply line V _CC , connecting the source of the FET 8 to the connection C, and connecting the connection D to the ground line, the LED indicator lamp 1 and the FET 8 are connected in series with the DC power supply. You may connect.

A resistor 9 is connected between the connecting portions A and B on the side of the LED marker light 1. On the control unit 2 side, a current path is formed when the FET 8 is off, and when the FET 8 is off, LE
The circuit unit 10 for limiting the voltage V _AB between the connection parts A and B of the D marker lamp 1 to a level smaller than the predetermined level V _ST is provided by the FE
It is connected in parallel with T8 (that is, between the drain and source of FET8). Further, the first
The photocoupler 11 as first current detection means for detecting whether or not a current of a predetermined level I ₁ or more is flowing,
Is provided.

In this embodiment, the light emitting diode 11a of the photocoupler 11 serving as the first current detecting means is also used as a part of the circuit section 10, and the circuit section 10 includes the zener diode 12 and the light emitting diode 11a. In series. The cathode of the Zener diode 12 is connected to the drain of the FET 8, the anode of the Zener diode 12 is connected to the anode of the light emitting diode 11a, and the cathode of the light emitting diode 11a is connected to the FET 8.
8 sources.

In this embodiment, when the FET 8 is in the off state, the voltage V _D across the circuit section 10 is equal to the breakdown voltage of the Zener diode 12 and the light emitting diode 1.
1a, the voltage V _AB between the connection points A and B
Is the voltage of the power supply line V _CC (for convenience of explanation, this voltage is also V
_{Expressed as CC} . ) Minus the voltage V _D across the circuit section 10. Therefore, in the present embodiment, a Zener diode having a breakdown voltage such that V _AB (= V _CC −V _D ) <V _ST is used as the Zener diode 12. For example, along with the voltage V _CC of the power supply line V _CC is + 24V, when the predetermined level V _ST of LED warning lights 1 is + 8V (i.e., connecting portions A, B
(When the LED marker lamp 1 emits light only when the voltage between them becomes +8 V or more), the voltage V _AB between the connection parts A and B becomes +8
As the V is smaller than + 6V, as a Zener diode 12, the voltage V _D across the circuit portion 10 is + 18V
A Zener diode having a breakdown voltage such that

The first predetermined level I _{1 serving as} a current detection reference for the photocoupler 11 is such that when the FET 8 is in the OFF state, the power supply line V _CC → the connection C → the line 6 → the connection A → the resistor 9 → connection portions B → line 7 → connection portions D → circuit 10 (zener diode 12 → the light emitting diode 11a) → is set smaller than the level I ₀ of the current flowing in the path of the ground line. That is, when a current flows through the above-mentioned path when the FET 8 is off, the phototransistor 11b of the photocoupler 11 is turned on, and the circuit section 10
Is set so that the phototransistor 11b is turned off when no current flows through the phototransistor 11b.

In the present invention, the configuration of the circuit section 10 is not limited to the configuration described above. For example, in FIG. 1, the Zener diode 12 may be replaced with a resistor (not shown). In this case, the voltage V _AB between the connection points A and B when the FET 8 is off is determined by the voltage dividing ratio of the resistor 9 and the resistor used in place of the Zener diode 12. By selecting the resistance value, V _AB (= V _CC -V _D ) <V _ST may be set.

In the present invention, the first current detecting means is not limited to the photocoupler 9. For example, replacing the light emitting diode 11a of the photocoupler 9 in the resistor (not shown), a comparator or the like determines whether the voltage across the resistor is a predetermined level or higher corresponding to the predetermined level I ₁ , May be used as the first current detecting means.

Next, the operation of the LED marker light system shown in FIG. 1 will be described.

When the FET 8 is turned off in response to the light emission control signal (that is, when the LED indicator lamp 1 is not to emit light), if the lines 6 and 7 are not disconnected, the power supply line V _CC → Connection part C → Line 6 → Connection part A → Resistor 9 → Connection part B → Line 7 → Connection part D → Circuit part 10 (Zener diode 12 → Light emitting diode 11a) → Current flows on the route of the ground line, photo The phototransistor 11b of the coupler 11 is turned on. At this time, since the voltage between the connection parts A and B is limited to a level lower than the predetermined level V _ST by the circuit part 10, the LED marker lamp 1 (that is, the LED 3) does not emit light, and therefore the marker There is no risk of false recognition. On the other hand, if the lines 6 and 7 are disconnected while the FET 8 is in the off state, the path is cut off, no current flows through the circuit section 10, and the photocoupler 1
One phototransistor 11b is turned off.

Therefore, when the FET 8 is off, the on state of the phototransistor 11b of the photocoupler 11 indicates that the lines 6 and 7 are not disconnected, and the off state of the phototransistor 11b of the photocoupler 11 indicates that the line is off. This indicates that the lines 6 and 7 are disconnected, and it is possible to detect whether or not the lines 6 and 7 are disconnected.

On the other hand, in response to the light emission control signal,
When the LED 8 is in the ON state (ie, when the LED indicator lamp 1 is about to emit light), both ends of the circuit section 10 are short-circuited by the FET 8, so that the circuit section 10 does not operate and the line 6 , 7 are not disconnected, the voltage of the power supply line V _CC (for example, +24)
V) is applied as it is and a voltage higher than the predetermined level V _ST is applied, so that the LED marker light 1 emits light.

When the FET 8 is in the ON state, no current always flows through the circuit section 10 irrespective of whether or not the lines 6 and 7 are disconnected. Not detectable. However, in the LED marker light system, the period during which the LED marker lamp 1 does not emit light is much longer than the period during which the LED marker lamp 1 emits light, so that there is no problem in practical use.

When the FET 8 is on, the photodiodes 11b of the photocoupler 11 are turned off even when the circuits 6 and 7 are normal. It is not preferable to use the disconnection detection signal. Therefore, for example, a logical sum (OR) of a state in which the light emission control signal turns off the FET 8 and an OFF state of the photodiode 11b.
, And the output of this circuit may be used as a final disconnection detection signal for the lines 6 and 7. Based on this detection signal, a known circuit can be used to turn on the display or generate a sound from a buzzer or the like, thereby generating an alarm for disconnection of the lines 6 and 7.

As described above, the LE according to this embodiment is
According to the D marker light system, the disconnection of the lines 6 and 7 between the LED marker lamp 1 and the control unit 2 can be detected without fear of erroneous recognition of the marker.

Next, an LED marker light system according to another embodiment of the present invention will be described with reference to FIG. FIG.
1 is a circuit diagram showing an LED marker light system according to the present embodiment.

In FIG. 2, the same or corresponding components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The LED marker light system shown in FIG. 1 cannot detect a short circuit in the lines 6 and 7 (that is, a short circuit in the connection portions C and D), whereas the LED marker light system shown in FIG.
The ED marker lamp system is configured to detect not only the disconnection of the lines 6 and 7 but also the short circuit.

The LED beacon lighting system shown in FIG. 2 is different from the LED beacon light system shown in FIG. 1 in that a current of a _second predetermined level I ₂ higher than the _first predetermined level I ₁ is supplied to the circuit section 10. A resistor 13 and a photocoupler 14 as second current detecting means for detecting whether or not the current is flowing;
Is added.

In this embodiment, the resistor 13 serving as the second current detecting means and the light emitting diode 14a of the photocoupler 14 are also used as a part of the circuit section 10. It comprises a series circuit of a diode 12, a resistor 13 and a light emitting diode 11 a of a photocoupler 11, and a light emitting diode 14 a of a photocoupler 14 connected in parallel to the resistor 13. The cathode of the Zener diode 12 is connected to the drain of the FET 8, the anode of the Zener diode 12 is connected to one end of the resistor 13, the other end of the resistor 13 is connected to the anode of the light emitting diode 11a, and the light emitting diode 1
The cathode of 1a is connected to the source of the FET 8, the anode of the light emitting diode 14a is connected to the one end of the resistor 13, and the cathode of the light emitting diode 14a is connected to the other end of the resistor 13. In FIG. 2, the photodiode of the photocoupler 11 and the photodiode of the photocoupler 14 are omitted.

As in the case of the LED marker light system shown in FIG. 1, the Zener diode 12 has V _AB (= V _CC -V
_D ) A Zener diode having a breakdown voltage that satisfies <V _ST is used.

As in the case of the LED marker light system shown in FIG. 1, the first predetermined level I _{1 serving as} a current detection reference for the photocoupler 11 is determined when the FET 8 is in the off state.
Power supply line V _CC → Connection C → Line 6 → Connection A → Resistor 9 → Connection B → Line 7 → Connection D → Circuit 10 (Zener diode 12 → Resistor 13 → Light emitting diode 11)
a) → Current level I ₀ ′ flowing in the ground line path
It is set smaller.

In the present embodiment, the second predetermined level I _{2, which} is a current detection reference by the resistor 13 and the photocoupler 14, is set higher than the current level I ₀ ′, and the FET 8 is turned off. In this state, the connections C and D are short-circuited, and the power supply line V _CC → the connection C → the connection D → the circuit 10 (the Zener diode 12 → the resistor 13)
And the light emitting diode 14a → the light emitting diode 11a) →
The level I ₀ ″ (>) of the current flowing through the ground line path
I ₀ ′). With such a setting, the phototransistor of the photocoupler 14 is turned on only when the level of the voltage across the light emitting diode 14a (that is, the voltage drop of the resistor 13) is equal to or higher than a predetermined level. Can be set. Therefore, in this embodiment, specifically, when a current at the level I ₀ ′ flows through the circuit section 10, the phototransistor of the photocoupler 14 does not turn on, and the current at the level I ₀ ″ flows through the circuit section 10. The resistance value of the resistor 13 may be set so that the phototransistor of the photocoupler 14 is turned on when flowing.

Next, the operation of the LED marker light system shown in FIG. 2 will be described.

When the FET 8 is turned off in response to the light emission control signal (ie, when the LED indicator lamp 1 is not to emit light), the lines 6 and 7 are normal without disconnection or short circuit. For example, power supply line V _cc → connection C → line 6 → connection A → resistor 9 → connection B → line 7 → connection D
→ Circuit part 10 (Zener diode 12 → Resistor 13 →
A current flows through the light emitting diode 11a) → ground line path, and the phototransistor of the photocoupler 11 is turned on. However, the current level is not enough to turn on the phototransistor of the photocoupler 14, so that The phototransistor remains off. At this time, since the voltage between the connection parts A and B is limited to a level lower than the predetermined level V _ST by the circuit part 10, the LED marker lamp 1 (that is, the LED 3) does not emit light, and therefore the marker There is no risk of false recognition.

When the FET 8 is off, the lines 6, 7
Is disconnected, the path is cut off, no current flows through the circuit section 10, and both the phototransistors of the photocoupler 11 and the photocoupler 14 are turned off.

When the FET 8 is off, the lines 6, 7
Is short-circuited, the power supply line V _CC → connection C → connection D →
A large current flows through the circuit section 10 (the Zener diode 12 → the resistor 13 and the light emitting diode 14a → the light emitting diode 11a) → the ground line, and the photocoupler 11
The phototransistor of the photocoupler 14 is turned on.

Therefore, when the FET 8 is off, the off state of the phototransistor of the photocoupler 11 indicates the disconnection of the lines 6 and 7, and the on state of the phototransistor of the photocoupler 14 indicates the short circuit of the lines 6 and 7. Thus, disconnection and short circuit of the lines 6 and 7 can be detected.

On the other hand, in response to the light emission control signal,
When the LED 8 is in the ON state (ie, when the LED indicator lamp 1 is about to emit light), both ends of the circuit section 10 are short-circuited by the FET 8, so that the circuit section 10 does not operate and the line 6 , 7 are normal, the voltage of the power supply line V _CC (for example, +24 V) is applied almost as it is between the connection points A and B, and a voltage higher than the predetermined level V _ST is applied. 1 emits light.

When the FET 8 is in the ON state, no current always flows through the circuit section 10 regardless of whether the lines 6 and 7 are disconnected or short-circuited, and the phototransistors of the photocouplers 11 and 14 are Since both are always in the off state, it is not possible to detect whether the lines 6 and 7 are disconnected or short-circuited. However, in the LED marker light system, the period during which the LED marker lamp 1 does not emit light is much longer than the period during which the LED marker lamp 1 emits light, so that there is no problem in practical use.

When the FET 8 is on, the photodiode of the photocoupler 11 is turned off even if the lines 6 and 7 are not disconnected. , 7 are not preferable. Therefore, for example, a circuit for taking a logical sum (OR) of a state where the light emission control signal turns off the FET 8 and an OFF state of the photodiode of the photocoupler 11 is added, and the output of this circuit is sent to the final lines 6 and 7. May be used as the disconnection detection signal. On the other hand, when the FET 8 is in the ON state, the photodiode of the photocoupler 14 is always in the OFF state and does not enter the ON state. I just need. Based on the detection signal of the disconnection or short circuit, a known circuit can be used to turn on the display or generate a sound from a buzzer or the like to generate an alarm for disconnection or short circuit of the lines 6 and 7.

As described above, the LE according to this embodiment is
According to the D marker light system, not only the disconnection of the lines 6 and 7 between the LED marker lamp 1 and the control unit 2 but also a short circuit can be detected without fear of erroneous recognition of the marker.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

For example, in FIG. 2 as well, by connecting the drain of the FET 8 to the power supply line V _CC , connecting the source of the FET 8 to the connection C, and connecting the connection D to the ground line, The FET 8 may be connected in series with the DC power supply. Also in this case, the circuit unit 10 is connected in parallel with the FET 8.

Also, in FIG. 2, the Zener diode 12 may be replaced by a resistor (not shown). In this case, the voltage V _AB between the connection points A and B when the FET 8 is off is determined by the voltage dividing ratio of the resistor 9 and the resistor used in place of the Zener diode 12. By selecting the resistance value, V _AB (=
V _CC −V _D ) <V _ST may be set.

Further, the second current detecting means is not limited to the configuration using the photocoupler 14.

[0057]

As described above, according to the present invention,
The connection state of the line between the LED marker light and the control unit can be detected without fear of misidentification of the marker.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating an LED marker light system according to an embodiment of the present invention.

FIG. 2 is a circuit diagram illustrating an LED marker light system according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED marker light 2 Control part 3 LED 6,7 line 8 FET 9 Resistor 10 Circuit part 11 Photocoupler 12 Zener diode 13 Resistor 14 Photocoupler A, B, C, D connection part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31/02

Claims (2)

(57) [Claims] [Claim 1 further comprising one or more LED and first and second connecting portions, wherein the one or more only when a predetermined level or higher voltage is applied between the first and second connecting portions LE
LE in which current flows through D and the one or more LEDs emit light
A D marker light, a control unit connected to the first and second connection units of the LED marker light via a line to control the light emission of the LED marker light, and A control unit having switching means for turning off the LED marker light and the switching means connected in series to a DC power supply; and a first and second connection unit on the LED marker light side. A first resistor connected therebetween, connected in parallel with the switching means on the control unit side, and when the switching means is in an off state,
A current path is formed, and a voltage between the first and second connection portions of the LED indicator lamp is limited to a level lower than the predetermined level so that a current flows through the one or more LEDs.
An LED marker light system comprising: a circuit means for preventing the current from flowing; and a first current detecting means for detecting whether or not a current of a first predetermined level or more is flowing through the circuit means. 2. The apparatus according to claim 1, further comprising second current detecting means for detecting whether or not a current equal to or higher than a second predetermined level is flowing through said circuit means. The LED marker light system according to claim 1.