JPH0460854B2 - - Google Patents

Description

[Detailed description of the invention] Technical field The present invention relates to a turn signal device.

BACKGROUND ART A conventional example of a vehicle-mounted blinker device is shown in FIG. In this device, left and right direction indicator lamps 1 _L ,
1 _R are provided, and are selectively selected by operating the direction indication selection switch 2. The selection switch 2 has an intermediate position in which it is in a non-selected state, and direction indicator lamps 1 _L and 1 _R are connected to its fixed contacts.
is connected. A power supply voltage V _B is supplied to the movable contact of the selection switch 2 via a current detection resistor 3 and a relay switch 4 . Relay switch 4 is turned on when relay coil 5 is excited.
A power supply voltage V _B is supplied to one end of the relay coil 5 , and the other end is grounded via the collector and emitter of the switching transistor 6 . An oscillator 8 is connected to the base of the transistor 6 via a resistor 7.
is connected. On the other hand, the voltage across the current detection resistor 3 is supplied to a discrimination circuit 9 consisting of a comparator. The determination circuit 9 determines filament breakage in each of the two direction indicator lamps 1 _L and 1 _R from the voltage across the current detection resistor 3, and supplies the determination result to the oscillator 8. When the selection switch 2 is turned on, the oscillator 8 starts oscillation by, for example, a switch linked thereto and generates an oscillation signal to the transistor 6, and the oscillation frequency changes according to the determination result of the determination circuit 9. I'm starting to do that.

In this configuration, when the selection switch 2 is operated and turned on from the intermediate position to one of the fixed contacts, the oscillator 8 starts oscillating, and the oscillation signal is supplied to the base of the transistor 6 via the resistor 7. be done. As a result, the transistor 6 starts to turn on and off, and the voltage V _B is intermittently applied to the relay coil 5 at the oscillation frequency of the oscillator 8.
Therefore, since the relay switch 4 is turned on and off, the current due to the voltage _VB is intermittently passed through the resistor 3, the relay switch 4, the selection switch 2, the direction indicator lamp _1L ,
Or it flows through 1 _R to ground, direction indicator lamp 1
It flashes _L or 1 _R. At this time, the current flowing through the direction indicator lamp 1 _L or 1 _R is the resistance 3
is detected as a voltage across both ends. Discrimination circuit 9
When the terminal voltage of the resistor 3 drops below a predetermined voltage when the transistor 6 is turned on, the output is inverted from a low level to a high level. The oscillator 8 changes its oscillation frequency in response to this high level output. For example, if two direction indicator lamps _1L are flashing and the filament of one lamp breaks,
The current flowing through the series circuit of resistor 3, relay switch 4, selection switch 2, and the other direction indicator lamp _1L is reduced by about 1/2, so the voltage across resistor 3 drops below a predetermined voltage, causing oscillator 8 to oscillate. The frequency becomes higher. Therefore, the other direction indicator lamp 1 _L blinks faster, and the one direction indicator lamp 1 _L blinks faster.
The driver etc. will be notified of the filament breakage.

However, in such a turn signal device, since it is necessary to provide a current detection resistor in the current path of the direction indicator lamp, there is a problem that if the current detection resistor has a large value, the illuminance of the direction indicator lamp decreases.

As a turn signal device that solves these problems,
A resistor is installed in parallel with the relay switch, and current is supplied to the direction indicator lamp through the resistor during the turn-off period of the direction indicator lamp, and filament breakage of the direction indicator lamp is detected from the terminal voltage of the direction indicator lamp immediately after the relay switch is turned off. The device for
It is shown in the publication No. However, since it is necessary to constantly supply current to the direction indicator lamp, there is a drawback that electric power is wasted.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a turn signal device that can detect filament breakage of a direction indicator lamp without wasting power.

The turn signal device of the present invention includes a parallel circuit of a switching element and a capacitor connected in series to a plurality of lamps connected in parallel, a power supply that applies voltage to the series circuit consisting of the plurality of lamps and the parallel circuit, and a turn signal. It is characterized by including a driving means for repeatedly turning on and off the switching element in response to a starting command, and a detecting means for detecting disconnection of a plurality of lamps according to the rate of increase in the voltage stored in the capacitor when the switching element is turned off.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 2 and 3.

The turn signal device for in-vehicle direction indication, which is an embodiment of the present invention shown in FIG. 2, is provided with a direction indication selection switch 12 and a turn signal switch 13 operated by the same operator (not shown). There is. The direction indication selection switch 12 is a lock switch, has no intermediate position, and has a fixed contact 12.
Direction indicator lamps 11 _L and 11 _R are connected to a and 12b. The movable contact of the direction selection switch 12 is supplied with a voltage V _B (for example, 12V). On the other hand, the turn signal switch 13 has three fixed contacts 13.
It is a non-lock switch having contacts 13a, 13b and 13c, and its movable contact 13d is grounded. A switch operation detection circuit 14 is connected to the fixed contacts 13a, 13b, and 13c to detect the ON operation of the turn signal switch 13. The detection circuit 14 is composed of, for example, a flip-flop, and generates a high-level output in response to the fall of the input signal level of the terminal S connected to the fixed contacts 12a and 12b, and outputs a high level output in response to the fall of the input signal level of the terminal R connected to the fixed contact 12c. Returns to low level output in response to falling edge. Note that voltage Vcc is supplied to the connection line between fixed contacts 12a and 12b via resistor 20a, and voltage Vcc is supplied to the connection line between fixed contact 12c via resistor 20b. An oscillator 15 is connected to the output of the detection circuit 14. The oscillator 15 performs oscillation only while the high level output of the detection circuit 14 is supplied. A frequency divider 16 is connected to the oscillator 15, and the output signal of the oscillator 15 and the output signal of the frequency divider 16 are selectively selected by a frequency changeover switch 17. A movable contact at the selection output end of the frequency selector switch 17 is connected via a resistor 18 to the base of an NPN transistor 19 as a switching element. The collector of the transistor 19 is connected to the common connection line of the direction indicator lamps 11 _L and 11 _R , and the emitter is grounded.

A capacitor 21 is connected in parallel between the collector and emitter of the transistor 19.
The voltage across both ends of 1 is supplied to the voltage comparator circuit 22 .
A voltage divided by the resistors 23 and 24 of _VB is supplied to the comparator circuit 22 as a reference voltage Vr. An AND circuit 25 is connected to the output of the comparison circuit 22,
The AND circuit 25 performs a logical product of the output signal of the comparison circuit 22 and the inverted signal of the selection output signal of the changeover switch 17 by the inverter 26. AND circuit 25
A digital counter 27 is connected to the output of the clock generator 28, and the counter 27 counts the clock pulses output from the clock generating circuit 28 in accordance with the output signal of the AND circuit 25. The count value of the counter 27 is sent to the digital comparison circuit 3 via the latch circuit 29.
0 and is compared with a reference value output from a memory 31 such as a ROM. The latch circuit 29
In response to the fall of the output signal of the AND circuit 25, the count value of the counter 27 is read and the count value is held and output. The output signal of the comparison circuit 30 is supplied to the control end of the changeover switch 17, and controls the selection operation of the changeover switch 17. Note that the voltage Vcc is obtained by stabilizing the voltage V _B by a voltage regulator 32.

In the turn signal device according to the present invention having such a configuration, for example, when the operator is moved in one predetermined direction, the direction indication selection switch 12 is turned on with respect to the fixed contact 12a as shown in the figure, and the movable contact of the turn signal switch 13 is turned on. 13d and fixed contact 13a are turned on. This becomes a turn signal activation command, and the input level of the terminal S of the switch operation detection circuit 14 is reversed from a high level to a low level as shown in FIG. A high level output is provided to oscillator 15. Therefore, the oscillator 15 starts its oscillation operation and generates a first oscillation signal (for example, 170 cpm) as shown in FIG. 3b. This first
The oscillation signal is frequency-divided by the frequency divider 16 to produce a second oscillation signal (for example, 85 cpm) as shown in FIG. 3c.
becomes. When the output level of the comparator circuit 30 is low, that is, the direction indicator lamp 11 _L or 11 _R selected by the direction indicator selection switch 12
When no filament breakage occurs, the selector switch 17 switches to the frequency divider 1 as shown in FIG. 3d.
The second oscillation signal output from the transistor 6 is relayed to the base of the transistor 19 via the resistor 18. Since the transistor 19 is turned on and off in response to the second oscillation signal, the current caused by the voltage _VB continuously flows to the ground via the direction indicator selection switch 12, the direction indicator lamp _11L , and causes the direction indicator lamp _11L to blink.

For example, when the operators of the switches 12 and 13 are pressed, the state of the switch 12 is maintained and the movable contact 13d and fixed contact 13c of the turn signal switch 13 are pressed.
is turned on. As a result, the input level of the terminal R of the switch operation detection circuit 14 is inverted from high level to low level, so that the switch operation detection circuit 14
When detecting a fall due to this level inversion, it supplies a low level output to the oscillator 15. Therefore, since the oscillator 15 stops its oscillation operation, the transistor 1
9 is turned off and the direction indicator lamp _11L stops flashing.

Further, when the operator is moved in parallel in another predetermined direction, for example, the direction indication selection switch 12 is turned on with respect to the fixed contact 12b, and the turn signal switch 1 is turned on.
The movable contact 13d and fixed contact 13b of No. 3 are turned on, and the above-mentioned movable contact 13d and fixed contact 13a are turned on.
The direction indicator lamp 11 _R flashes in the same manner as when the is turned on.

When the transistor 19 is on, the capacitor 21
Since both ends of the capacitor 21 are shorted, the stored charge in the capacitor 21 is discharged and the voltage at both ends becomes 0V. When the transistor 19 is off, the current due to the voltage V _B flows through the direction indication selection switch 12, the direction indication lamp _11L ,
or 11 _R , the capacitor 21, and the ground, the capacitor 21 is discharged and the voltage across it rapidly rises as shown in FIG. 3e. When the terminal voltage of the capacitor 21 is lower than the reference voltage Vr, the output level of the comparator circuit 22 becomes a high level as shown in FIG. 3f. In addition, the output level of the inverter 26 is set by switching the changeover switch 1 as shown in FIG. 3g.
Since it is the inverted signal of the signal output from 7,
As shown in FIG. 3h, the AND circuit 25 generates a high level pulse representing the time it takes for the voltage across the capacitor 21 to reach the reference voltage Vr from 0V. In response to the generation of this pulse, the counter 27 is reset and counts clock pulses from the initial value. When the high level pulse disappears, the counter 27
stops counting, and the counted value is held in the latch circuit 29. The count value C held in the latch circuit 29 is compared with the reference value Cr in the comparison circuit 30. When the filament of the selected direction indicator lamp 11 _L or 11 _R is normal and not broken, the terminal voltage of the capacitor 21 rises rapidly, so that the count value C becomes smaller than the reference value Cr. Therefore, the output level of the comparison circuit 30 becomes a low level.

Assuming that the direction indicator lamp 11 _L is selected by the direction indicator selection switch 12, in the case of an abnormality in which one filament of the direction indicator lamp 11 _L is disconnected at time t, the capacitor 21
Since the current flowing through the capacitor 21 decreases, the rate of increase in the voltage across the capacitor 21 decreases compared to before the filament was disconnected. Since the time from when the transistor 19 is turned off until the voltage across both ends reaches the reference voltage Vr, that is, the time width of the high-level pulse output from the AND circuit 25, becomes longer, the count value C of the counter 27 becomes lower than the reference value Cr. Becomes large. Therefore, the output level of the comparator circuit 30 becomes a high level as shown in FIG. It is relayed to the base of transistor 19. Since the transistor 19 is turned on and off according to the first oscillation signal, the other direction indicator lamp 1 _L
The blinking frequency becomes higher (for example, twice) to notify the driver etc. that one filament of the direction indicator lamp _11L is broken. This operation is the same even when one of the filaments of the direction indicator lamp _11R is disconnected.

In the embodiment of the present invention described above, all operations are performed by hardware, but the terminal voltage of the capacitor 21 is A/D converted and supplied to the microprocessor. By repeatedly executing a predetermined program, it is also possible to obtain the operation of supplying the first oscillation signal or the second oscillation signal to the base of the transistor 19 via the resistor 18 in the same manner as described above.

In addition, in the above-described embodiment of the present invention, when the filament of one lamp is broken, the lamp blinking frequency increases, but it may be lowered.
The lamp may stop flashing and remain lit.

In the above-described embodiment, the capacitor 21 is directly connected to the connection line between the collector of the transistor 19 and the direction indicator lamp, but the capacitor 21 is connected to this connection line via a current adjustment resistor. 21 may be supplied to the comparator circuit 22.

Effects of the Invention As described above, in the turn signal device of the present invention, a parallel circuit of a switching element and a capacitor is connected in series to a plurality of parallel-connected lamps, and the stored voltage is reduced by charging the capacitor when the switching element is off. Detects disconnection of multiple lamps depending on the rising speed. Therefore, there is no need to provide a current detection resistor in the lamp current path when the lamp is turned on, and since the capacitor quickly completes charging when the switching element is turned off, wasteful power consumption can be prevented. Further, since there is no need to provide a mechanical switching element such as a relay switch in the conventional device, it is possible to reduce the size and improve reliability.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing a conventional example of a turn signal device.
FIG. 2 is a circuit diagram showing an embodiment of the present invention, and FIG. 3 is a waveform diagram showing the operation of each part of the device shown in FIG. Explanation of symbols of main parts, 1 _L , 1 _R , 11 _L , 1
1 _R ... Direction indicator lamp, 2, 12... Direction indicator selection switch, 13... Turn signal switch, 8,
15... Oscillator.

Claims (1)

[Claims] 1. A parallel circuit of a switching element and a capacitor connected in series to a plurality of parallel-connected lamps, and a power supply that applies voltage to the series circuit consisting of the plurality of lamps and the parallel circuit. , a drive means for repeatedly turning on and off the switching element in response to a turn signal activation command, and a detection means for detecting disconnection of the plurality of lamps according to a rate of increase in the voltage stored in the capacitor when the switching element is turned off. A blinker device characterized by the following. 2. The blinker device according to claim 1, wherein the drive means changes the on/off frequency of the switching element when the detection means detects a disconnection of the plurality of lamps.