JP3232609B2 - Lighting control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling lighting of a headlight of a discharge lamp provided in a vehicle.

[0002]

2. Description of the Related Art Conventionally, a halogen lamp is generally used as a headlight provided in a vehicle. In recent years, the use of metal halide lamps, which are a type of high-pressure discharge lamps, in place of these lamps has been actively attempted. because,
This is because, unlike the conventional halogen lamp, the high-pressure discharge lamp has features such as long life and high efficiency.

On the other hand, this high-pressure discharge lamp also has a drawback. Since the starting voltage and the lighting maintenance voltage are high, the DC voltage of a DC power supply is generally boosted and converted into an AC voltage by a lighting circuit such as an inverter circuit. It is configured to be applied to a high pressure discharge lamp.

On the other hand, the operating voltage range of a battery, which is a DC power supply used in a vehicle, is 10 to 16 V,
It is used in the range of 2 to 13V. However,
There is a problem that the range of the actually used voltage of the battery changes beyond the range of 10 to 16 V due to the state of the vehicle, the use environment, and the change over time of the battery (change in the concentration and amount of the electrolyte).

FIG. 4 shows an example of a conventional example of the above-described vehicle lighting control device. The configuration includes a DC power supply 1 such as a battery, a plurality of lighting circuits 10 and 20 driven by a DC voltage from the DC power supply 1, and a high-voltage discharger connected to the lighting circuits 10 and 20 for lighting. The vehicle is provided with headlights L1 and L2 of electric lights and a switch S1 for controlling blinking of the headlights L1 and L2 provided in the vehicle.

The operation state will be described below with reference to the operation explanatory diagram shown in FIG. At time t3 when the engine is started after the headlights L1 and L2 are turned on, a phenomenon occurs in which the DC voltage VB of the battery 1 temporarily drops to about 5 to 6V. At low temperatures, the battery 1
DC voltage VB decreases, and if the insufficient charging or the like further overlaps, the voltage drops below the lower limit of the use range of 10 V, and it becomes difficult to start the engine (time t6 to t8).

As described above, since the DC voltage VB of the battery 1 is greatly reduced, the starting voltage of the high-pressure discharge lamps L1 and L2 cannot be ensured without being ensured, or the lamps go out during lighting. In particular, there is a problem that safety is hindered if the problem occurs during traveling.

Therefore, it is necessary to provide a device capable of ensuring safety. In this case (which does not normally occur but rarely occurs), for example, the voltage fluctuation range of the DC voltage VB is, for example, 5V.
A device capable of satisfying a wide range from to 16 V is required, which causes a problem that the size of the device is increased and the cost is increased.

[0009]

In the above conventional example, when the DC voltage of the battery is abnormally lowered, there is a problem that all headlights are turned off or pointed out. In order to solve the problem, there has been a problem that the size of the apparatus and the cost are increased. An object of the present invention is to provide a lighting control device for a vehicle that can run safely even when the DC voltage is abnormally lowered for some reason.

[0010]

According to the present invention, there are provided a plurality of lighting circuits driven by a DC voltage from a DC power supply, a headlight of a high-pressure discharge lamp which is connected to each of the lighting circuits and lights. A headlight control circuit that controls the lighting circuit to control the lighting output of a headlight provided in the vehicle, wherein the headlight control circuit includes
Operating voltages of the lighting circuits are different from each other by the DC voltage.
When the DC voltage of the DC power supply falls below a predetermined level, at least one of the plurality of high-pressure discharge lamps is kept turned on and the other high-pressure discharge lamps are turned off.

[0011]

According to the present invention, since the operating voltage of the lighting circuit is set by the DC voltage of the battery or the like (for example, in the case of a 12V battery, the operating voltage is 2V such as 10V and 8V or 8V and 6V).
If the battery voltage drops, a difference occurs in the operating voltage between the lighting circuits, so that at least one headlight can be maintained. Therefore, the headlight control circuit is configured to control the operating voltage of the plurality of lighting circuits.
Are set by different DC voltages respectively
Therefore, when the DC voltage of the DC power supply drops below a predetermined level, at least one of the plurality of high-pressure discharge lamps can be kept turned on and the other high-pressure discharge lamps can be turned off, and the other high-pressure discharge lamps can be turned off. At the same time, at least one lamp is lit and maintained along with the suppression of the decrease in the DC voltage due to this, and there is an effect that nighttime traveling becomes possible.

[0012]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention. The configuration different from FIG. 4 shown in the prior art example is that the lighting circuits 10a and 20a are respectively composed of DC-DC converters 21 and 22 and inverters 31 and 32, and that the DC voltage of the DC power supply 1 is It is provided with voltage detection determination circuits 41 and 42 for detecting. The same portions are denoted by the same reference numerals, and duplicate description will be omitted.

The operation state will be described below. When the switch S1 is turned on, a DC voltage is supplied from the DC power supply 1 and the DC-DC converter 21 receives the DC voltage.
The DC voltage that has been driven and stepped up or stepped down is output. The inverters 31 and 32 are driven by receiving the DC voltages from the respective DC-DC converters 21 and 22 to output a high-frequency voltage or a low-frequency rectangular wave voltage. The headlights L1 and L2 of the high-pressure discharge lamp are started and turned on in response to the high-frequency voltage or the low-frequency rectangular wave voltage.

Here, the voltage detection determination circuit 41 is a DC-
A resistor R3 connected between the input terminals of the DC converter 21;
A series circuit of R4 and a resistor R for dividing the reference voltage VREF
1 and R2, and a connection point between the respective series circuits is connected to an input terminal, and a voltage across a resistor R4 is connected to a resistor R2.
And a comparison circuit 51 that outputs an L level when the voltage becomes lower than the voltage across the resistor R2. The voltage across the resistor R2 is set to 8V. Similarly, the voltage detection determination circuit 42 also includes resistors R5 to R8 and a comparison circuit 52, and the voltage across the resistor R6 is set to 6V.

After the headlights L1 and L2 of the high-pressure discharge lamp are started and lit, for some reason as described above,
When the DC voltage of the battery 1, which is a DC power supply, abnormally drops to 8 V or less, the output of the lighting circuit 10a is limited, and the headlight L1 of the high-pressure discharge lamp is turned off. Due to the light-off, the DC voltage slightly changes in the rising direction due to the lightening of the load, and the lighting circuit 20a can continue the lighting state by providing the setting voltage of the light-off detection voltage at 6 V in advance.

Here, needless to say, a hysteresis circuit may be added to make a difference between the light-off detection voltage value and the light-off detection voltage value.

With this configuration, the operating voltage of the lighting circuits 10a and 20a is set by the DC voltage of the battery 1 (8V and 6V for a 12V battery).
Therefore, when the voltage of the battery 1 decreases, a difference occurs in the operating voltage between the lighting circuits 10a and 20a, and at least one headlight L2 can be maintained.

Accordingly, when the DC voltage of the DC power supply 1 falls below a predetermined level, at least one of the plurality of discharge lamps L1, L2 is controlled by the headlight control circuits 41, 42.
The other discharge lamps L1 can be turned off while maintaining the lighting,
At least one of the discharge lamps L1 is kept turned on while the decrease in the DC voltage is suppressed by turning off the other discharge lamps L1, and there is an effect that nighttime traveling becomes possible.

FIG. 2 shows a second embodiment of the present invention. The configuration different from the first embodiment is that the DC-DC converters 21 and 22 shown in FIG.
A DC converter 23, a headlight control circuit 41,
42 is input to the inverters 31a and 32a. The same portions are denoted by the same reference numerals, and duplicate description will be omitted.

Here, DC-D which is a boost chopper circuit
The C converter 23 has switches S1 at both ends of the DC power supply 1.
, A transistor Q1 connected to both ends of the smoothing capacitor C1 via an inductor CH1, and a smoothing capacitor C1 connected to both ends of the transistor Q1 via a diode D1.
2, which receives a DC voltage from a low-voltage DC power supply 1 such as a battery, boosts the DC voltage to a predetermined DC voltage, and supplies the boosted DC voltage to the inverters 31a and 32a.

Therefore, when the DC voltage of the DC power supply 1 drops below a predetermined level, at least one of the plurality of discharge lamps L1, L2 is controlled by the headlight control circuits 41, 42.
The other discharge lamps L1 can be turned off while maintaining the lighting,
At least one of the discharge lamps L1 is kept turned on together with the suppression of the decrease in the DC voltage by turning off the other discharge lamps L1, so that the vehicle can be driven at night and can be constituted by one DC-DC converter 23. This has the effect that it becomes easier.

FIG. 3 shows a third embodiment of the present invention. The configuration different from the second embodiment is that the lighting control device 3 shown in FIG.
The point is that a system for two sets of multiple lights, in which the two lights a and 3b are set as one set. Here, the illumination control device 3a side is formed for a blinking switch S1, a DC-DC converter 23a, a headlight control circuit 43a, inverters 31a and 32a, and a low beam for passing each other. And high-pressure discharge lamps L1 and L2. The lighting control device 3b includes a blinking switch S2, a DC-DC converter 23b, a headlight control circuit 43b, and an inverter 3.
1b and 32b, and headlights L3 and L4 of high-pressure discharge lamps formed for traveling high beams. The same portions are denoted by the same reference numerals, and duplicate description will be omitted.

Hereinafter, the operation state will be briefly described. Now, it is assumed that the set voltage of the turn-off detection voltage of the headlight control circuit 43a is set to 6V, and the set voltage of the turn-off detection voltage of the headlight control circuit 43b is set to 8V. If the DC voltage of the DC power supply 1 drops abnormally in such a state,
First, the headlights L3 and L4, which are high-pressure discharge lamps for traveling, are turned off, and the headlights L1 and L of the remaining high-pressure discharge lamps for passing each other are turned off.
2 keeps lighting, and safe operating conditions are secured. In this example, two lights are turned off. However, it is needless to say that a configuration in which three lights are turned off is also possible.

[0024]

According to the present invention, a plurality of lighting circuits driven by a DC voltage from a DC power supply, a headlight of a high-pressure discharge lamp connected to each of the lighting circuits for lighting, and the lighting circuit are provided. A headlight control circuit that controls the lighting output of a headlight provided in the vehicle by controlling the headlight control circuit,
Operating voltage is set by different DC voltage
When the DC voltage of the DC power supply falls below a predetermined level, at least one of the plurality of high-pressure discharge lamps is kept turned on and the other high-pressure discharge lamps are turned off. Even if the voltage of the DC power supply abnormally drops for some reason, at least one lamp is maintained to be turned on, and there is a remarkable effect that night driving is possible.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention.

FIG. 4 is a circuit configuration diagram showing a conventional example of the present invention.

FIG. 5 is an operation explanatory diagram for explaining a conventional example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 10a Lighting circuit 20a Lighting circuit L1 Headlight of discharge lamp L2 Headlight of discharge lamp 41 Headlight control circuit 42 Headlight control circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05B 41/16 B60Q 1/04 H05B 41/24-41/29

Claims (1)

(57) [Claims] 1. A direct-current power supply, a plurality of lighting circuits driven by a direct-current voltage from the direct-current power supply, a headlight of a high-pressure discharge lamp connected to and lit by each of the lighting circuits,
A headlight control circuit for controlling a lighting output of a headlight provided in the vehicle by controlling the lighting circuit, wherein the headlight control circuit includes a plurality of lighting devices.
The operating voltage of the circuit is controlled by the different DC voltages.
Set, the said plurality of high-pressure discharge lamp when the DC voltage of the DC power supply drops below a predetermined level, lighting control, characterized in that so as to turn off the other of the high pressure discharge lamp is maintained at least 1-lamp apparatus.