JPH06135285A - Lamp run-out detecting device - Google Patents

Abstract

(57) [Abstract] [Purpose] A lamp that can flexibly respond to an increase or change in the lamp specifications of a stop lamp or a tail lamp, and that can handle vehicle models with different lamp specifications without adjustment using the same device. A break detection device is provided. [Structure] A voltage generated in a current detection resistor 3 connected in series with a stop lamp 4 is detected by a microcomputer 6 via a V / F converter 5. The microcomputer 6 stores the current when the lamp is normally turned on at the time of normal lighting, calculates a disconnection detection current value corresponding to the current when one lamp is disconnected, and stores it. Then, when the detected lamp current value is lower than the disconnection detection current value, a lamp disconnection alarm is output and the alarm lamp 9 is turned on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp burnout detecting device for warning a driver that a stop lamp or a tail lamp of an automobile is broken.

[0002]

2. Description of the Related Art In a conventional device of this type, as shown in FIG. 5, a current detecting resistor 3 having a small value is inserted in series in a circuit of a stop lamp or a tail lamp, and a voltage generated in the current detecting resistor 3 and a reference voltage are applied. The comparator 13 compares the reference voltage set by the resistors 11 and 12 with the comparator 13, and when the voltage generated in the current detection resistor 3 is small, an alarm output is generated and the alarm lamp 9 provided in the driver's seat is turned on. It was

[0003]

However, in the above-mentioned conventional device, the voltage generated in the current detection resistor 3 is different for the vehicle models having different lamp specifications, so that the reference resistor 11,
12 settings need to be changed. In recent years, as the number of automobiles has increased, the specifications of stop lamps or tail lamps have also increased, and it has been necessary to arrange lamp disconnection detection circuits for each specification. In addition, when the number of lamps increases, such as 5 or 6 lamps, the rate of change in current when one lamp is broken is smaller than in the case of 2 or 3 lamps. The disconnection detection range became narrow, making adjustment difficult. Further, when the number of lamps such as high-position lamps is increased at the user's request, the conventional lamp burnout detection circuit has a fixed specification, so that the alarm is not always output properly even if one lamp burns out. was there. The present invention has been made to solve the above problems, and an object thereof is to be able to flexibly cope with an increase and a change in lamp specifications, and to use the same device for vehicle models having different lamp specifications. An object of the present invention is to provide a lamp burnout detection device that can deal with the problem.

[0004]

In order to achieve the above object, the present invention is a lamp burnout detecting device for a stop lamp or a tail lamp, which comprises a current detecting means for detecting a lamp current and an initial value of the lamp current. An initial current value storage means for storing, a disconnection detection current value storage means for calculating and storing a disconnection detection current value corresponding to the current value when one lamp is disconnected from the initial current value, and the currently detected lamp current It is characterized by further comprising: comparing means for comparing the value with the burnout detection current value; and alarm means for outputting a lamp burnout alarm when the current lamp current value is lower than the burnout detection current value.

[0005]

In the lamp burn-out detecting device configured as described above, the initial current value storage means stores the value of the current when the lamp is fully lit, and the disconnection detection current value is calculated and stored from that value. The disconnection detection current value is automatically calculated, so no adjustment is required. When one lamp is burnt out, the lamp current value becomes smaller than the burnout detection current value, is detected by the comparison means, and the lamp burnout alarm is output by the alarm means.

[0006]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a hardware configuration of an embodiment of the present invention. A brake switch 2 is connected to a vehicle power supply (battery) 1, and a current detection resistor 3 is inserted in series between the brake switch 2 and a plurality of stop lamps 4. The voltage generated in the current detection resistor 3 is input to the microcomputer 6 via the V / F converter (voltage / frequency converter) 5. Further, the voltage of the battery 1 is input to the V / F converter 7, and its output is output to the microcomputer 6
Entered in. The microcomputer 6 is a CPU, RO
This is a well-known one having M and RAM. The output of the microcomputer 6 is connected to a lamp driving transistor 8 so as to light an alarm lamp 9 provided in the driver's seat.

FIG. 2 is a flow chart for explaining the operation of the microcomputer 6. When the battery 1 is connected and power is supplied to the microcomputer 6, the process 10 is performed.
0 is started. In step 101, the brake switch 2 is turned on and the stop lamp 4 is turned on. The lighting of the stop lamp 4 is detected by the output of the V / F converter 5. When the stop lamp 4 is turned on, the process proceeds to step 102. In step 102, the V / F converter 7
The voltage of the battery 1 is detected and stored by the output of. Next, at step 103, the lamp current value is detected from the output of the V / F converter 5 and stored in the lamp current memory LCM. In step 104, the disconnection detection current value is calculated and set from the stored current value, and the lamp fail memory LFM is set.
The process to be stored in is executed.

FIG. 3 is a flowchart showing the disconnection detection current value setting process in step 104. When the process 200 is started, in step 201, the lamp current converted value LC ₁₂ at 12V is calculated by multiplying the lamp current value LC detected in step 103 by a variable Ex related to the voltage of the battery 1. The variable Ex is a variable indicating a value larger than 1 when the battery voltage is lower than 12V and a value smaller than 1 when the battery voltage is higher than 12V. In step 202, it is checked whether or not the converted lamp current value LC ₁₂ is smaller than the predetermined value a. If it is smaller than the predetermined value a, in step 203, the disconnection detection current value b is stored and set in the lamp fail memory LFM. Next, in step 204, the lamp current conversion value LC ₁₂ is examined whether large predetermined value a ₁ is smaller than or not than a predetermined value a, while the lamp current conversion value LC ₁₂ is the predetermined value a ₁ and a predetermined value a If so, in step 205, the disconnection detection current value b ₁ is stored and set in the lamp fail memory LFM. Similarly, the lamp current conversion value LC ₁₂ is the predetermined value a.
_{Between 1} and the predetermined value a ₂ , it is checked one after another whether it is between the predetermined value a ₂ and the predetermined value a _3, and if so, b ₂ and b ₃ are respectively set as the disconnection detection current values. It is stored and set in the lamp fail memory LFM.

Then, in step 210, it is checked whether or not the lamp current conversion value LC ₁₂ is between the predetermined value a _n-1 and the predetermined value a _n, and if so, in step 211 the burnout detection current is detected. The value b _n is the lamp fail memory LFM
Stored in the memory, otherwise, converted value of the lamp current L
Since C ₁₂ is larger than the predetermined value a _{n, in} step 212, the disconnection detection current value b _{n + 1} is the lamp fail memory LF.
It is stored and set in M. In this way, the disconnection detection current values b, b ₁ , b according to the magnitude of the lamp current conversion value LC _12
2 ... _Bn and bn _{+ 1} are selected and stored. Thus, the disconnection detection current value setting routine is completed, and the process returns from step 213 to step 105 in FIG.

Referring again to FIG. 2, description will be made. Step 1
At 05, it waits until the brake switch 2 is turned on and the stop lamp 4 is turned on. The lighting of the stop lamp 4 is detected by the output of the V / F converter 5. When the stop lamp 4 is turned on, the process proceeds to step 106. Step 10
In 6, the voltage of the battery 1 is detected and stored by the output of the V / F converter 7. Next, at step 107, the lamp current value LC is detected from the output of the V / F converter 5, and the lamp current value LC is changed to a variable Ex related to the voltage of the battery 1.
The lamp current conversion value LC ₁₂ at 12 V is calculated by multiplying by. In step 108, the converted lamp current value LC ₁₂
And the disconnection detection current value b stored and set in the lamp fail memory LFM in step 104 are compared. If the lamp current conversion value LC ₁₂ is smaller than the burnout detection current value set in the lamp fail memory LFM, it means that one or more lamps have been burnt out, so the routine proceeds to step 110, where the lamp driving transistor 8 is used. To drive the alarm lamp 9 provided in the driver's seat. If the lamp current conversion value LC ₁₂ is larger than the disconnection detection current value, it is normal, and the process directly proceeds to step 109.

In step 109, the lamp current value stored in the lamp current memory LCM in step 103 is compared with the lamp current value LC detected in step 107. If the lamp current value LC detected in step 107 is larger than the lamp current value stored in the lamp current memory LCM, it is considered that the lamp current value increased due to the addition of the stop lamp 4, so step 10
Returning to 3, the lamp fail memory L of the disconnection detection current value b
Set the FM again. If the lamp current value LC detected in step 107 is smaller, it is normal.
The process directly returns to step 105 and waits for detection of the lamp current.

The operation of the above-described processing will be briefly described. When the automobile is assembled and the battery 1 is connected, the routine proceeds to step 101, and waits for the brake switch 2 to be turned on. When the brake switch 2 is first turned on and the brake lamp 4 is turned on, the routine proceeds from step 102 to step 104, where the lamp current value is stored and the disconnection detection current value is calculated and set and stored. Step 103 constitutes an initial current value storage means for storing the initial value of the lamp current, and the processing of step 104 calculates and stores the disconnection detection current value corresponding to the current value when one lamp is disconnected from the initial current value. A disconnection detection current value storage means is configured.

While the vehicle is in operation, the process waits for the brake switch 2 to be turned on in step 105. When the brake switch 2 is turned on, the current lamp current value is detected in step 107, and is compared with the disconnection detection current value in step 108. Nothing is done in a normal state, and steps 105 to 10
Repeat 9. When the brake lamp 4 is additionally installed on the way, it is detected by the increase of the lamp current value, and the process returns from step 109 to step 103 to reset the disconnection detection current value. At this time, the battery voltage detected in step 106 is used. If one or more of the brake lamps 4 are burnt out, it is detected by the decrease in the lamp current value, and the process jumps from step 108 to step 110 to turn on the warning lamp 9 in the driver's seat. Step 10
Reference numeral 8 constitutes a comparing means for comparing the currently detected lamp current value with the burnout detection current value, and step 110 is an alarm means for outputting a lamp burnout alarm when the current lamp current value is lower than the burnout detection current value. Make up.

In the embodiment described above, the process of step 104 of calculating and setting the current value for detecting disconnection and storing it in the lamp fail memory LFM is executed by the process shown in FIG.
Other methods are also possible. FIG. 4 is a flowchart showing another embodiment of the disconnection detection current value setting process in step 104. When the process 300 starts, step 30
In step 1, the lamp current value LC detected in step 103 is multiplied by a variable Ex related to the voltage of the battery 1 to calculate a lamp current conversion value LC ₁₂ at 12V. Figure 3 up to here
Is the same as the processing of. Next, in step 302, a predetermined value LCO is subtracted from the converted lamp current value LC ₁₂ to obtain a disconnection detection current value, which is stored in the lamp fail memory LFM.
The predetermined value LCO is a lamp current value per brake lamp at 12V. This completes the disconnection detection current value setting routine and returns from step 303 to step 105 in FIG. This embodiment is suitable when the brake lamp 4 is composed of only lamps having the same wattage.
When a combination of high wattage lamps having different wattages is combined, the above embodiment is more preferable.

In the above embodiment, V / F is used to detect the voltage.
Although the converters 5 and 7 are used, an A / D converter may be used although the cost is high. Although the brake lamp has been described as an example in the embodiment described in detail above, it is obvious that the present invention can be applied to the tail lamp as it is.

[0016]

As described above, the lamp burn-out detection device of the present invention has the above-mentioned configuration and calculates the burnout detection current value corresponding to the current value when one lamp is burnt from the initial current value. A burnout detection current value storage means for storing, a comparison means for comparing the currently detected lamp current value with the burnout detection current value, and a lamp burnout alarm is output when the current lamp current value is lower than the burnout detection current value. It is possible to flexibly deal with the increase and change of the lamp specifications because it is equipped with an alarm means that operates, and it is possible to respond to vehicle models with different lamp specifications without adjustment with the same device. There is.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a hardware configuration of an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the microcomputer.

FIG. 3 is a flowchart showing a disconnection detection current value setting routine.

FIG. 4 is a flowchart showing a second embodiment of a disconnection detection current value setting routine.

FIG. 5 is a circuit diagram showing a conventional lamp burnout detection device.

[Explanation of symbols]

 1 Battery 2 Brake Switch 3 Current Detection Resistor 4 Stop Lamp 5 V / F Converter (Voltage / Frequency Converter) 6 Microcomputer 9 Alarm Lamp

Claims (1)

[Claims] 1. A lamp burnout detection device for a stop lamp or a tail lamp, comprising: current detection means for detecting a lamp current; initial current value storage means for storing an initial value of the lamp current; A burnout detection current value storage means for calculating and storing a burnout detection current value corresponding to the current value at the time of one burnout, a comparing means for comparing the currently detected lamp current value with the burnout detection current value, and a current A lamp burnout detection device, comprising: an alarm unit that outputs a lamp burnout alarm when the lamp current value is lower than the burnout detection current value.