JPS5918044A - Bulb lighting confirming device - Google Patents

Abstract

PURPOSE:To achieve safety driving through a car light lighting confirmation device, by utilizing the filament resistance variation under lighting to detect and alarm the blow-out of bulb or the shortcircuit. CONSTITUTION:Upon closing of a power source switch 9, bulbs 3a, 3b will light and since the resistance of each filament is low at the initial conduction stage the input to the terminal 5b of a comparator 5 will be low to produce high level output and the output of AND gate 8 will energize a buzzer or an indication lamp through an amplifier circuit 8a. Upon increase of the filament temperature to steady state, the input to the terminal 5b will increase to the referential voltage from the terminal 5a thus to flicker the alarm signal from an alarm 10 and to confirm the lighting state. When any one of the bulbs 3a, 3b is blown off, the combined resistance will be doubled to increase the input voltage at the terminal 5b while upon occurrence of shortcircuit, the output from an operational amplifier 2 will disappear to bring the input voltage at the terminal 5b to zero thus to function the alarm 10.

Description

[Detailed description of the invention] This type of light bulb with a tungsten filament is related to a device that allows a driver to confirm from the seat whether an indicator light for illumination or other purposes is illuminated. When the light is off, the resistance increases by about 10 times compared to when the light is off.Using this change in resistance value, accidents such as filament breakage and short circuits in the wiring between filaments can be detected, and this can be reported to the driver. A feature of the present invention is that it is possible to obtain a device that provides notification using a buzzer sound, a lamp display, a voice monitor, etc. Furthermore, when a light bulb is replaced, it is common for the resistance of the filament to vary slightly, and embodiments 1 to 1 below will now be described to prevent erroneous signals caused by such changes.

In FIG. 1, light bulbs 3a and 3b are, for example, brake lights. This lights up when you step on the brakes, and is intended to notify following vehicles that the brakes have been applied to prevent rear-end collisions and other accidents. Cars also have lamps for number plate illumination, headlights,
There are parking lights and the like, but the device of the present invention can be applied to all of these.

Symbols 1a and ■b are positive and negative electrode terminals of the on-vehicle storage battery. When the electric switch 9 is manually closed, the light bulb 3a,
3b is turned on by being energized through the resistor 4a. Resistor 4a
The resistance used is about 1/30 of the resistance of the filament of a light bulb when it is lit. Since the resistor 4a consumes power, the value of the resistor 4a is selected to be as small as possible so that the entire operation can be performed reliably.

The operational amplifier 2.3 amplifies the voltage drops across the light bulbs 3a, 3b and the resistor 4a, respectively, and the output of the operational amplifier 2.3 is input to the X and Y terminals of the a-circuit 4.

The output of the operational amplifier 2.3 is R when the filament resistances of the light bulbs 3a and 3b are equal.

And if the resistance value of the resistor 4a is R2, then each is 0.
5R, I, R2■. Therefore, the output V of the division circuit 4 is V:o5R+/R2 (the proportional constant is omitted), that is, the output of the division circuit 4 is proportional to the combined resistance value of the light bulbs 3a and 3b since R2 is a constant.

Symbol 5 is a window comparator, which has the characteristics shown in FIG. 2(a). The horizontal zero point is when the two inputs of the window comparator 5 (hereinafter simply referred to as comparator 5) (one input is from the reference voltage source and is input from the terminal 5a) are equal. The positive and negative symbols on the left and right indicate cases where the output of the division circuit 4 is larger or smaller than the input voltage of the terminal 5a. In this circuit, the output of the part indicated by arrow A is at a low level, and changes to a high level when the above-mentioned differential voltage reaches a set value.

The above-mentioned comparator 5 can be made, for example, as shown in FIG. 2(b).

In Figure 2 (l), operational amplifier 180 input terminal 1
When the input voltage at terminal 8a becomes larger than that at terminal 18b and exceeds the shift voltage of diodes 21a and 21b, the output at terminal 17 becomes high level. Conversely, when the input voltage at the terminal 18a becomes smaller than that at the terminal 18b, the output is inverted to a positive level via the inverting amplifier circuit 19 with a gain of 1, and
Due to the presence of the shift voltage at 20b, the output at terminal 17 converts to a high level when the shift voltage is exceeded.

The output of the division circuit 4 of FIG. 1 is inputted to the terminal 18aK, and the reference voltage input terminal 5a becomes the terminal 18b.

Returning to Figure 1, the electric switch (this will be the power switch)
9 is closed, one input of the AND circuit 80 is at a high level.

The part indicated by the symbol 10 is, for example, l<I' fuser or a well-known rung indicator. The power for these is the wiring 10a
, 10b.

Next, the effects of the above-mentioned device will be explained.

When the power switch 9 is closed, the light bulbs 3a and 3b are energized and lit. At the beginning of energization, the resistance of each filament is small, so the input to terminal 5b of comparator 5 is small, and the output of comparator 5 is at a high level. The buzzer or indicator lamp lights up. However, the temperature of the filament soon rises and reaches a steady state, so terminal 5
Since the input of b increases and becomes equal to the input voltage of terminal 5a, the output of comparator 5 changes to low level.
The notification signal 〒IY-'' from the notification device 10 also disappears instantaneously. 2 This operation confirms the lighting. Also light bulbs 3a, 3b
If you replace the filament, there will be a slight difference in the resistance value of the filament. However, as mentioned above, the output of the comparator 5 has a dead zone shown by the arrow A in FIG. 2(a), which has the characteristic of preventing the generation of erroneous signals.

As can be seen from the above explanation, the input voltage of the terminal 5a is set in accordance with the value of the combined resistance of the filaments of the light bulbs 3a and 3b. Further, the comparator 5 is regulated so that there is no output when the light is turned on.

As mentioned above, the instantaneous activation of the notification device 10 at the same time as the power switch 90 is turned on is meant to notify that the lighting confirmation circuit is operating without failure, so this time should be approximately a few seconds. That's good. For this purpose, the amplifier circuit 8
It is effective to provide a delay circuit in a to perform the above-described operation.

In this embodiment, two light bulbs are arranged in parallel, but one light bulb may be used. If either light bulb 3a or 3b is disconnected, the combined resistance value will be 2.
Since the voltage is doubled, the input voltage at the terminal 5b of the comparator 5 increases (in the case of one light bulb, it becomes significantly large).

) Therefore, the input voltage of the AND circuit 8 is also at a high level, so that the buzzer sounds or the indicator lamp lights up, which has the effect of notifying an accident.

The same effect can be obtained even if there is poor contact between the sockets of the light bulbs 3a and 3b. Also, due to reasons such as (=1), an accident may occur in which the supporting conductor of the filament is welded and short-circuited, or a short-circuit in the wiring occurs.In this case, the output of the operational amplifier 2 may be lost, or the operational amplifier 2 may .3 and the output of the divider circuit 4 are also eliminated, the input type 1 voltage of the terminal 5b is also at zero level, and therefore the notification device 10 is activated to notify the driver of the accident.

If the notification device 10 is a well-known voice monitor, it is possible to notify the accident by voice.

As can be understood from the above explanation, both disconnection and short circuit accidents can be reported without being affected by irregularities in the filament resistance of the light bulb, and if necessary,
It has the feature that it can inform the driver whether the notification circuit is operating or not when the power is turned on.It also has the feature that the operation is stable and reliable. This is due to the following two reasons, one of which is the existence of a dead zone indicated by arrow A in FIG. 2(a). Another reason is that the resistance value of the filament during lighting is detected and compared with the input of the terminal 5a of the reference voltage source to obtain a detection output via a dead zone.

Next, another embodiment shown in FIG. 3 will be described.

Components with the same symbols as those in the previous embodiment are the same members.

The light bulbs 3a and 3b in FIG. 1 are used with the same input, for example, can be used as left and right taillights of a car.

However, if the device of the present invention is constructed using one type of IC circuit for two light bulbs with different inputs, for example, a headlight and a taillight (sol lamp), the embodiment shown in FIG. 1 cannot be used. . In such a case, the embodiment of FIG. 3 is used. The light bulb 3a has a brightness for headlights, and the lightbulb 3b has a low brightness for taillights.
The resistance of the filament is on the order of 1:10. If the resistance value of the filament of the light bulb 3a when lit is R, then
The resistance value of the filament of the light bulb 3b is nR (n=10). Assuming that the resistance value of the resistor 4a is R and the resistance value of the resistor 4b is nR, the voltages at point D and point F are equal during lighting. Therefore, the circuit including the operational amplifier 2.3, the division circuit 4, the comparator 5, the reference voltage 5a, and the AND circuit A, which is an electric circuit for detecting an accident in the light bulb 3a, was converted into an IC, and the same IC was created. (indicated by dotted line G) can be applied to the light bulb 3b. By inputting the output of the circuit G and the output of the AND circuit 8 as two inputs of the exclude/boor circuit 12, a light bulb 3a is generated.

When an accident occurs with any of the bulbs 3b, an output is obtained from the exclusive OR circuit 12, and this output activates the notification device IO, allowing the driver to know that there is an accident with one of the bulbs. be. In the embodiment described above, two light bulbs are used, but it is effective in the case of a plurality of light bulbs because a corresponding number of the same IC circuits can be used.

The embodiment shown in FIG. 4 is a case in which the apparatus of the present invention is configured with one detection IC circuit in the case of the above-mentioned light bulbs 3'a and 3b. Items with the same symbols as in the previous embodiment are the same parts. Therefore, the explanation will be omitted.

In FIG. 4, reference numeral 13 denotes a multivibrator, which oscillates at a predetermined frequency (a relatively low frequency, which may have a period of about 0.5 seconds). The oscillation output of the multivibrator 13 causes the transistors lla,
The base inputs of llb are alternately made, so that they are alternately conducting and non-conducting. Therefore, the light bulbs 3a, 3
Accident notifications regarding b are alternately input to the notification device 10 via the AND circuit 8. Light bulb 3a or 3
If an accident occurs in any of the sections b, a buzzer sound that lasts for 0.5 seconds is generated, for example, every 0.5 seconds, so the driver can detect the accident, such as a wire breakage. In this example, 2
Detection of accidents in light bulbs is performed using one IC detection circuit, but even in the case of n light bulbs, one IC
This can be done using a C-based detection circuit.

In this case, of course, the multivibrator 13
Instead, a counting circuit capable of dividing n numbers is energized by the output of the multi-by-break 13, n counting outputs are cyclically taken out, and the corresponding transistors (transistors lla, llb in FIG. The purpose is achieved by energizing the

In the embodiments of FIGS. 1 to 4, the positive electrode 1 for power supply
Generally, in the case of an automobile, a single electric wire is used to supply power from A, and the negative electrode side is grounded to the main body. According to the device of the present invention, one additional electric wire is required in order to return the accident signal of the lighting of the light bulb to the driver's seat. Since there are many types of light bulbs, there may be several return wires.

A means for eliminating this drawback is shown in FIG.

In FIG. 5, symbol 14 indicates the previous embodiment, the light bulb 3a,
3b, resistor 4 a % 4 b % operational amplifier 2.3,
It shows all the detection circuits including the Hi-removal circuit 4, the comparator 5, the AND circuit 8, etc. The output of the AND circuit 8 is taken out from the terminal 14b and modulated by the modulation circuit 15. The circuit indicated by the dotted line J is housed in, for example, a mounting portion of a headlight. Power is supplied from the power supply positive electrode 1a to the terminal 14a via the electric switch.The electrical signal modulated by the modulation circuit 15 is introduced into the electric wire supplying the power, and the demodulation circuit 16 converts the original electricity After being demodulated into a signal, the above-mentioned notification device 110
is input and the purpose is achieved.

It should be noted that any known means can be used for the modulation and demodulation circuits 15 and 16. The part surrounded by the dotted line indicates the components located in the driver's seat.

As can be seen from the above description, the apparatus of the present invention achieves the object stated at the beginning and has a significant effect on safe driving.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of the device of the present invention, FIG. 2 is a partial electric circuit diagram thereof, and FIGS. 3, 4, and 5 are diagrams of different embodiments of the device of the present invention. Shows an electrical circuit diagram. la, lb...power supply voltage negative pole, 2.3... operational amplifier, 3a13b--bulb, 4a, 4b=-resistor, 5 window comparator, 5a-reference voltage input terminal, 4...divider circuit, 8 AND circuit , 8a...Amplification circuit, 10...Notification device, 9
・Power switch, 18.. Operational amplifier, 19.. Gain 10 inverting amplifier circuit, 14. Detection circuit, 12.. Exclude OR circuit, 13. Lr f vibrator, lla, llb.. Transistor, 15.
...Modulation circuit, 16...Demodulation circuit. patent applicant

Claims (1)

[Claims] A series circuit including a power switch, a light bulb, and a resistor, a power supply to supply the series circuit, first and second differential amplifier circuits that amplify voltage drops due to the resistor and the light bulb, respectively, and a second differential amplifier circuit. A division circuit that divides the output of the amplifier circuit by a first differential circuit, and a resistance value of a predetermined width near the resistance value of the filament of the light bulb when the light bulb is lit, by comparing the output of the division circuit and a reference voltage. The present invention is characterized by being comprised of a window comparator that produces no output when the value exceeds that value, and provides an output when the value changes greatly or decreases beyond that value, and a notification device that reports that the small light bulb of the window comparator is lit. A device that checks whether a light bulb is lit.