JP2013256211A - Lighting device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device for a vehicle, which can be turned on at constant brightness, without changing luminance of an LED, even if the number of LEDs is changed.SOLUTION: A lighting device 1 for a vehicle includes light sets 2a and 2b formed by connecting a plurality of LEDs in series, a step-down circuit 61 for decreasing source voltage to the lowest lighting voltage required for turning on one LED constituting the light sets, a constant current circuit 62 for determining whether the voltage to the light sets is sufficient for turning on all the LEDs constituting the light sets, and a boosting circuit 63 for increasing the lowest lighting voltage until the constant current circuit 62 determines that the voltage is sufficient for turning on all th LEDs constituting the light sets, and outputting it to the light sets.

Description

  The present invention relates to a lighting device mounted on a vehicle, and more particularly to a vehicle lighting device used as a daytime running light using an LED.

  The daytime running light is mounted on the outside of the vehicle body to enhance the distinguishability of the vehicle running during the daytime. Recently, daytime running lights have been deployed in many vehicles, and the European Union has been required to provide daytime running lights on all sedans and light trucks since February 7, 2011. .

  The daytime running light needs to be lit for a long time while driving the vehicle, so power consumption is a problem, but the early daytime running light uses a halogen lamp, and the power consumption uses headlights. It was 25 to 30% of the case. However, the use of LEDs (light emitting diodes) has the advantages of small volume, low power consumption and long life, and uses only about 10% of the power consumption of headlights. Therefore, LEDs are now the most suitable light source for daytime running lights. Patent document 1 is disclosed as a prior art provided with such an LED daytime running light.

JP 2010-147025 A

 However, in the conventional control unit for controlling the daytime running light, the number of LEDs that are connected to the control unit to be lit is determined. Therefore, when the number of LEDs is changed, the luminance of the LEDs changes, and there is a problem that the user cannot freely change the number of LEDs. In particular, when the number of LEDs is reduced, the brightness of the LEDs becomes too bright and the standard of ECE (European Economic Commission) is not satisfied.

 Therefore, the present invention has been proposed in view of the above-described circumstances, and there is provided a vehicle lighting device that can be lit at a constant brightness without changing the luminance of the LEDs even if the number of LEDs is changed. The purpose is to provide.

  A vehicle lighting device according to the present invention includes a light set in which a plurality of light-emitting diodes are connected in series, and a step-down that lowers a power supply voltage to a minimum lighting voltage required to light one light-emitting diode constituting the light set. A circuit, a constant current circuit for determining whether or not a voltage to the light set is a voltage sufficient to light all the light emitting diodes constituting the light set, and the light set by the constant current circuit. And a booster circuit that boosts the minimum lighting voltage and outputs the boosted voltage to the light set until it is determined that the voltage is sufficient to turn on all the light emitting diodes.

  According to the vehicle lighting device of the present invention, the voltage is stepped down to the lowest lighting voltage by the step-down circuit and then boosted by the voltage boosting circuit until a voltage sufficient to light all the LEDs constituting the light set is detected. Therefore, even if the number of LEDs is changed, the LEDs can be lit at a constant brightness without changing the luminance of the LEDs.

It is a figure which shows the structure of the illuminating device for vehicles which concerns on one Embodiment of this invention. It is a figure which shows the structure of LED used for the illuminating device for vehicles which concerns on one Embodiment of this invention. It is the figure which showed the method of couple | bonding a bracket with LED used for the illuminating device for vehicles which concerns on one Embodiment of this invention. It is a perspective view which shows the state which couple | bonded the bracket with LED used for the illuminating device for vehicles which concerns on one Embodiment of this invention. It is sectional drawing which shows the state which couple | bonded the bracket with LED used for the illuminating device for vehicles which concerns on one Embodiment of this invention. It is a figure which shows the state which mounted the vehicle illuminating device which concerns on one Embodiment of this invention in the vehicle. It is a circuit diagram which shows the structure of the control apparatus of the illuminating device for vehicles which concerns on one Embodiment of this invention.

  Hereinafter, an embodiment to which the present invention is applied will be described with reference to the drawings.

[Configuration of vehicle lighting device]
FIG. 1 is a diagram illustrating a configuration of a vehicular illumination device according to the present embodiment. As shown in FIG. 1, the vehicle lighting device 1 according to this embodiment includes light sets 2a and 2b in which a plurality of LEDs (light emitting diodes) are connected in series, and a control device 3 that controls light emission of the LEDs. ing. However, although FIG. 1 shows an example in which there are two light sets, the number of light sets may be one or two or more.

  The light sets 2a and 2b are configured by connecting a plurality of LEDs 4 in series, and each LED 4 includes a case 111 and an LED element 112 installed inside the case 111, as shown in FIG. On the back surface of the case 111, a positive connection cable 113 provided with a male connection terminal 1131 and a negative connection cable 114 provided with a female connection terminal 1141 are connected. The positive and negative connection cables 113 and 114 are connected to the positive and negative connection cables 113 and 114 of the other LEDs 4 and connected in series. Thus, since LED4 is connected in series by the system in which the male connection terminal 1131 and the female connection terminal 1141 are sequentially inserted and fitted, a plurality of LEDs 4 can be detachably connected. As a result, the number and arrangement of LEDs can be freely changed according to the needs of the user, and even if any LED is damaged, it can be easily replaced independently, so that there is no need to replace the entire light set. Can be eliminated.

  Further, as shown in FIGS. 3 to 5, an inverted L-shaped bracket 30 is coupled to each LED 4 of the light sets 2 a and 2 b described above. The bracket 30 is formed of a vertical plate 31 and a horizontal plate 32, and the vertical plate 31 is provided on the rear side of the case 111 and provided with a round hole 311 through which the positive electrode connection cable 113 and the negative electrode connection cable 114 pass. . When the fixing screw 40 is passed through the round hole 311 and connected to the screw hole on the back surface of the case 111, the edge portion of the round hole 311 is fixed by the fixing screw 40, so that the bracket 30 can be fixed to the LED 4. it can. The horizontal plate 32 is provided with two notch grooves 321 for fixing the LED 4 to the outside of the vehicle with a fixing screw. In use, the brackets 30 are used to mount the LEDs 4 of the two light sets 2a and 2b at the front bumper 50 outside the vehicle or at other positions outside the vehicle as shown in FIG.

  As shown in FIG. 1, the control device 3 includes a positive power supply cable 25 and a negative power supply cable 26 connected to a vehicle ACC power supply, a control cable 27 connected to a vehicle headlight, and two sets of positive connection cables. 28 and the negative electrode connection cable 29 are connected. A male connection terminal 281 is provided at the end of the two sets of positive connection cables 28, and a female connection terminal 291 is provided at the end of the negative connection cable 29. The male connection terminal 281 and the female connection terminal 291 are respectively connected to the male connection terminal 1131 and the female connection terminal 1141 at both ends of the light sets 2a and 2b.

  Next, the circuit configuration of the control device 3 will be described with reference to FIG. As shown in FIG. 7, the control device 3 turns on the step-down circuit 61 that steps down the power supply voltage to the lowest lighting voltage, and the LEDs to the light sets 2a and 2b turn on all the LEDs constituting the light sets 2a and 2b. A constant current circuit 62 that determines whether or not the voltage is sufficient, a booster circuit 63 that boosts the lowest lighting voltage and outputs the boosted voltage to the light sets 2a and 2b, and a light set when a vehicle headlight is turned on. And a luminance switching circuit 64 for reducing the luminance of the LEDs constituting 2a and 2b.

  Here, the step-down circuit 61 includes a choke coil 401, a step-down IC 402, capacitors 403 and 404, a diode 405, and resistors 406 and 407, and the step-down IC 402 turns ON / OFF the current flowing through the choke coil 401. Therefore, the power supply voltage 12V is stepped down to 6.4V. As a result, the step-down circuit 61 steps down the power supply voltage to the lowest lighting voltage necessary for lighting one LED 4 constituting the light sets 2a and 2b.

  The constant current circuit 62 includes a transistor 501 and resistors 502 to 505, and determines that the voltage to the light sets 2a and 2b is sufficient to light all the LEDs 4 constituting the light sets 2a and 2b. Then, the transistor 501 is turned on to feed back a constant current to the booster circuit 63. Thereby, the constant current circuit 62 determines whether or not the voltage to the light sets 2a and 2b is a voltage sufficient to light all the LEDs 4 constituting the light sets 2a and 2b.

  The booster circuit 63 includes a choke coil 601, a booster IC 602, capacitors 603 and 604, a diode 605, a transistor 606, and resistors 607 to 611, and the booster IC 602 turns the transistor 606 on and off to turn on the choke coil. The current flowing through 601 is turned ON / OFF, thereby boosting the voltage output from the step-down circuit 61. At this time, the boosting IC 602 gradually increases the voltage by adjusting the duty ratio, and stops the boosting operation when receiving the feedback current from the constant current circuit 62. Thus, the booster circuit 63 boosts the minimum lighting voltage until the constant current circuit 62 determines that the voltage is sufficient for lighting all the LEDs constituting the light sets 2a and 2b, thereby increasing the light sets 2a and 2b. Output to.

  The luminance switching circuit 64 includes transistors 701 to 703, a Zener diode 704, and resistors 705 to 710. When the headlight is turned on, the transistors 701 and 702 are turned off to increase the voltage by the resistor 708. For example, when the voltage exceeds 15 V, the Zener diode 704 outputs a constant voltage to turn on the transistor 703. As a result, the luminance switching circuit 64 reduces the current flowing to the light sets 2a and 2b by passing the current from the constant current circuit 62 to the transistor 703, and configures the light sets 2a and 2b when the vehicle headlights are turned on. The brightness of the LED is reduced.

[Operation of control device]
In the control device 3 of this embodiment, when the ACC power supply is turned on at the time of starting the vehicle engine, the lighting of the daytime running light is automatically controlled. First, the power supply voltage is stepped down to the lowest lighting voltage necessary for lighting a single LED by the step-down circuit 61 of the control device 3. Specifically, when the power supply voltage is applied to the step-down circuit 61, the backflow of the current is prevented by the diode 405, and then the current that flows to the choke coil 401 is turned ON / OFF to reduce the power supply voltage of 12V. The voltage is stepped down to the minimum lighting voltage, for example, 6.4V.

  When the lowest lighting voltage is output from the step-down circuit 61, the step-up circuit 63 next turns on / off the current flowing through the choke coil 601 by turning on / off the transistor 606 by the step-up IC 602. The minimum lighting voltage output from 61 is boosted. At this time, the booster IC 602 gradually increases the voltage by adjusting the duty ratio, and applies this output voltage to the light sets 2a and 2b.

  Then, the constant current circuit 62 determines whether or not the voltage to the light sets 2a and 2b output from the booster circuit 63 is a voltage sufficient to light all the LEDs 4 constituting the light sets 2a and 2b. When it is determined that the voltage is sufficient to turn on all the LEDs 4, the transistor 501 is turned on to feed back the current to the booster IC 602. The booster IC 602 that has received this feedback current fixes the duty ratio, and thereafter, a constant voltage is output from the booster circuit 63, and the LEDs 4 constituting the light sets 2a and 2b are lit with a constant luminance.

  As described above, the control device 3 according to the present embodiment reduces the power supply voltage by the step-down circuit 61 until the voltage reaches a voltage sufficient to light all the LEDs 4 constituting the light sets 2a and 2b. Therefore, the brightness of the LEDs 4 can be evenly lit regardless of the number of LEDs 4, no matter how many LEDs 4 are formed in the light sets 2 a and 2 b.

  Next, another function of the vehicle lighting device 1 according to this embodiment will be described. The vehicular lighting device 1 according to the present embodiment can be switched from use as a daytime running light to use as a position lamp by switching the luminance of the light sets 2a and 2b.

  When the vehicle lighting device 1 according to this embodiment is used as a daytime running light, when the vehicle headlight is turned on, the transistors 701 and 702 of the luminance switching circuit 64 are turned off. As a result, the current flowing through the resistor 708 increases and the voltage rises. For example, when the voltage exceeds 15 V, the Zener diode 704 outputs a constant voltage and the transistor 703 is turned on. When the transistor 703 is turned on, part of the current from the constant current circuit 62 flows to the transistor 703, so that the current flowing to the light sets 2a and 2b decreases, and the luminance of the LEDs 4 constituting the light sets 2a and 2b decreases.

  In this way, the luminance switching circuit 64 is controlled so as to reduce the luminance of the LEDs 4 constituting the light sets 2a and 2b, and the daytime running light is switched to use as a position lamp.

  On the other hand, when the headlight is turned off, the brightness of the LEDs 4 constituting the light sets 2a and 2b is controlled to be bright again by turning on the transistors 701 and 702 of the brightness switching circuit 64. Will return to use.

  As described above in detail, according to the vehicular illumination device 1 according to the present embodiment, after the voltage is lowered to the lowest lighting voltage by the step-down circuit 61, all the LEDs 4 constituting the light sets 2a and 2b are turned on. Since the voltage is boosted by the booster circuit 63 until a sufficient voltage is detected, even if the number of the LEDs 4 is changed, the brightness of the LEDs 4 can be turned on without changing. That is, the control device 3 can detect the number of LEDs 4 to automatically adjust the voltage and control the LEDs 4 to have uniform brightness. Therefore, the user can freely change the number, arrangement, and combination of the LEDs 4 as necessary, and can easily form various different shaped lighting effects.

  Moreover, according to the illuminating device 1 for vehicles which concerns on this embodiment, since several LED4 was connected so that attachment or detachment was possible respectively, a number and arrangement | sequence can be changed freely according to a user's need. In addition, even if any of the LEDs 4 is damaged, it can be easily replaced independently, so that the waste of replacing the entire light set can be eliminated.

  Furthermore, according to the vehicle lighting device 1 according to the present embodiment, when the vehicle headlights are turned on, the brightness of the LEDs 4 constituting the light sets 2a and 2b is reduced, so that the daytime running light is switched as a position lamp. The power of the light sets 2a and 2b can be saved and used for various purposes.

  The above-described embodiment is an example of the present invention. Therefore, the present invention is not limited to the above-described embodiment, and even if it is a form other than this embodiment, various modifications may be made depending on the design or the like as long as the technical idea of the present invention is not deviated. Of course, it can be changed.

DESCRIPTION OF SYMBOLS 1 Vehicle lighting device 2a, 2b Light set 3 Control device 4 LED
61 Step-down circuit 62 Constant current circuit 63 Step-up circuit 64 Luminance switching circuit

Claims (3)

A light set in which a plurality of light emitting diodes are connected in series;
A step-down circuit for stepping down a power supply voltage to a minimum lighting voltage necessary for lighting one light-emitting diode constituting the light set;
A constant current circuit for determining whether or not the voltage to the light set is a voltage sufficient to light all the light emitting diodes constituting the light set;
A boosting circuit that boosts the lowest lighting voltage and outputs the boosted voltage to the light set until it is determined that the constant current circuit is a voltage sufficient to light all the light-emitting diodes constituting the light set. An illumination device for a vehicle.   The vehicle lighting device according to claim 1, wherein each of the plurality of light emitting diodes is detachably connected.   The vehicle illumination device according to claim 1, further comprising a luminance switching circuit that reduces the luminance of the light emitting diodes constituting the light set when a vehicle headlight is turned on.

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