JP2015116914A - Lighting control device of lighting fixture for vehicle and lighting fixture system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve visibility of a turn lamp installed together with another lamp (DRL, for example).SOLUTION: A lighting control device of a lighting fixture for a vehicle, which is a device for controlling a lighting state of a lighting fixture for a vehicle, includes: (b) a switch M1 connected between a power source and the lighting fixture for a vehicle; (c) a switch control part for controlling the switch to an open state when an input signal from the outside is a relatively high first potential, and controlling the switch to a closed state when the input signal is a relatively low second potential; and (d) a fall detection part U1 for supplying a signal of the first potential to the switch control part only for a predetermined period of time when the fall detection part U1 detects the fall of the input signal from the outside.

Description

  The present invention relates to a lighting control technique for a vehicular lamp.

  As one of vehicular lamps, DRL (Daytime Running Lamps), which are lamps that are turned on mainly to inform pedestrians of the presence of a vehicle during the day, are known. As a conventional example related to this DRL, for example, Japanese Patent Laying-Open No. 2005-297594 (Patent Document 1) describes a semiconductor light emitting element and an ambient signal according to a signal from a sensor that outputs a signal corresponding to the brightness around the vehicle. A vehicle lamp is disclosed that includes a current control unit that increases the current flowing through the semiconductor light emitting device when the light is bright. According to this vehicular lamp, when the surroundings of the vehicle are bright, the vehicular lamp is made to emit light with a larger amount of light, so that even if the surroundings are bright, the presence of the running vehicle can be detected by pedestrians and other vehicles. The driver can be notified.

  By the way, when the DRL as described above is arranged in the vicinity of another lamp such as a turn lamp (direction indicating lamp), the blinking at the time of operation of the turn lamp or the like becomes difficult to see especially during the daytime. There is. This is because, as described above, the DRL is lit with a relatively large light amount, whereas a general turn lamp or the like has a relatively small light amount when blinking. On the other hand, a method of arranging the turn lamp and the DRL as far apart as possible is also conceivable. However, the installation volume allowed for the vehicular lamp in the entire vehicle is limited, and another measure is desired from the viewpoint of not impairing the degree of freedom of the design of the vehicular lamp.

JP 2005-297594 A

  A specific aspect according to the present invention is to provide a technique capable of improving the visibility of a turn lamp provided together with another lamp (for example, DRL).

  An apparatus according to an aspect of the present invention is (a) a device that controls the lighting state of a vehicular lamp, and (b) a switch connected between a power source and the vehicular lamp, and (c) an external device. A switch control unit for controlling the switch to be open when the input signal is at a relatively high first potential, and controlling the switch to be closed when the input signal is at a relatively low second potential; A lighting control device for a vehicular lamp including a falling detection unit that supplies a signal of a first potential to a switch control unit for a predetermined period when a signal falling is detected.

  According to the above configuration, the switch is controlled to be open when the turn signal is at the first potential by applying the turn signal (turn lamp driving signal) to the switch control unit as an external input signal. In addition, when the turn signal becomes the second potential, the signal of the first potential is supplied from the falling detection unit to the switch control unit corresponding to the fall, so that the switch is controlled to be in the open state. Maintained. Therefore, the DRL, which is the vehicle lamp, can be turned off while the turn signal is being output, that is, during the operation of the turn lamp, so that it is possible to improve the visibility of the turn lamp attached to the DRL. In addition, when the DRL and the turn lamp are also provided, the layout restriction is eliminated, so that the degree of freedom in designing the vehicular lamp can be increased.

  In the above lighting control device, it is also preferable that the predetermined period in which the signal of the first potential is supplied from the falling detection unit is set longer than the half cycle of the input signal from the outside.

  Thus, the signal of the first potential can be continuously supplied to the switch control unit more reliably until the next input signal from the outside becomes the first potential. That is, it is possible to more reliably maintain the DRL off state.

  The lighting control device preferably further includes an RC integration circuit connected between a supply terminal for an input signal from the outside and the switch control unit.

  As a result, the falling waveform of the input signal from the outside can be blunted, so that the rising timing of the first potential signal from the switch control unit is somewhat delayed with respect to the falling time of the input signal from the outside. Even so, it is possible to more reliably prevent the switch from being instantaneously closed. That is, it is possible to avoid that the DRL is turned on instantaneously.

  A system according to an aspect of the present invention is a vehicle lamp system including any one of the lighting control devices described above and a vehicle lamp controlled by the lighting control device.

  According to the above configuration, it is possible to obtain a vehicular lamp system capable of improving the visibility of a turn lamp provided together with another lamp (for example, DRL).

FIG. 1 is a circuit diagram illustrating a configuration of a lighting control device for a vehicular lamp according to an embodiment. FIG. 2 is a waveform diagram for explaining the operating state of the lighting control device.

  Embodiments of the present invention will be described below with reference to the drawings. In the present specification, the expression that a certain circuit element A and a certain circuit element B are “connected” includes other circuit elements (not shown) that are not connected to the circuit element A, as long as the intended operation in the circuit is not hindered. It is not excluded that it exists between B.

  FIG. 1 is a circuit diagram illustrating a configuration of a lighting control device for a vehicular lamp according to an embodiment. The lighting control device shown in FIG. 1 controls a lighting state of a DRL configured to include a plurality of light emitting elements (LEDs) D2, D3, and D4 using a turn signal obtained from a vehicle. . The lighting control device includes a plurality of transistors M1, M2, and M3, a plurality of diodes D1, D5, and D6, a plurality of resistance elements R1, R2, R3, R4, R5, R6, and R7, and a capacitance element C1. And a falling edge detection unit U1.

  In addition, the vehicle lamp system is configured including the lighting control device and the DRL controlled thereby in the present embodiment, and the “switch control unit” is configured including the transistors M2 and M3. The transistor M1 corresponds to a “switch”.

  The transistor M1 is a P-channel field effect transistor (PMOS), and is connected between the DRL signal supply source (power source) V3 and one end of the DRL. Specifically, one end of the current path of the transistor M1 is connected to the DRL signal supply source V3, and the other end is connected to the light emitting element D2 included in the DRL. Further, a resistance element R5 is connected between the gate of the transistor M1 and the DRL signal supply source V3. The other end of the DRL is connected to a reference potential end (ground potential end).

  The transistor M2 is an N-channel field effect transistor (NMOS), and is connected between the DRL signal supply source V3 and the reference potential terminal. Specifically, the transistor M2 has one end of the current path connected to the DRL signal supply source V3 via the resistance element R8, and the other end connected to the reference potential end.

  The transistor M3 is an N-channel field effect transistor (NMOS), is connected to the gate of the transistor M1, and is connected between the reference potential ends. A resistor element R6 is connected between the gates of the transistor M3 and the transistor M1. Specifically, one end of the current path of the transistor M3 is connected to the DRL signal supply source V3 via the resistance elements R5 and R6, and the other end of the current path is connected to the reference potential terminal.

  The diodes D5 and D6 are connected in series, one end of which is connected to the turn signal supply source V2, and the other end is connected to the gate of the transistor M2.

  The resistance element R7 is connected in parallel with the diode D5. Specifically, one end of the resistance element R7 is connected to the turn signal supply source V2, and the other end is connected to a contact point between the diode D5 and the diode D6.

  One end of the capacitive element C1 is connected to a contact between the diode D5 and the diode D6 (that is, the other end of the resistance element R8), and the other end is connected to a reference potential end. The capacitive element C1 and the resistive element R8 constitute an RC integrating circuit.

  The falling edge detection unit U1 has an input terminal (TRIG) connected to the turn signal supply source V2, and an output terminal (OUT) connected to the gate of the transistor M2 via the diode D1. The falling detection unit U1 outputs an on signal (a signal having a relatively high potential) when the falling of the turn signal is detected, and outputs an off signal (a signal having a relatively low potential) at other times. Output. Further, the falling detection unit U1 switches the output signal to the off signal when a predetermined time elapses after the on signal is output. Such a falling detection unit U1 can be realized by using, for example, a commercially available timer IC. The falling detection unit U1 is supplied with power from the power source V1, and is connected to the resistance elements R1, R2, and R3.

  The lighting control device of the present embodiment has the above-described configuration, and the operation will be described in detail next.

  FIG. 2 is a waveform diagram for explaining the operating state of the lighting control device. First, when the DRL is on (lit state) and the operation state (Turn / Hazard) of the turn hazard operation lever is off (non-lit state), the transistor M3 is turned on (conducting state). It is turned on (conductive state), and current is supplied to each of the light emitting elements D2 to D4 of the DRL.

  When the turn-hazard operation lever is turned on (lighted state) at the time “a” shown in the drawing, a turn signal is output from the turn signal supply source V2 accordingly. The waveform of the turn signal is indicated as “Turn Signal” in the figure. As shown in the figure, the turn signal is a pulse signal that periodically repeats a high potential and a low potential.

  The turn signal passes through the diodes D5 and D6 with a delay time (about 1 ms in the example shown) due to circuit characteristics (time b shown in the figure). The waveform of the signal passing through the diode D5 is indicated as “D5” in the drawing. When the turn signal that has passed through the diode D6 is applied to the gate of the transistor M2, the transistor M2 is turned on (conductive state) while the turn signal is at a high potential, and accordingly, the transistor M3 is turned off (non-conductive state). As a result, the transistor M1 is also turned off. Thereby, the current supply to the light emitting elements D2 to D4 of the DRL is stopped.

  Next, when the turn signal becomes low potential, the signal applied to the gate of the transistor M2 via the diodes D5 and D6 becomes low potential. However, the fall detection unit U1 detects the fall of the turn signal at this time, and outputs an ON signal from the output terminal. This on signal passes through the diode D1 and is given to the transistor M2, so that the transistor M2 is turned on (conducting state), and accordingly, the transistor M3 is turned off (nonconducting state). As a result, the transistor M1 is also turned off. Become. That is, since the transistor M1 is kept off while the turn signal is at a low potential, the state where the current supply to the light emitting elements D2 to D4 of the DRL is stopped is maintained.

  Here, the falling detection unit U1 outputs a turn signal after a predetermined period (for example, 0.6 s) longer than a half cycle of the turn signal, and then outputs an off signal. Thereby, it is possible to partially overlap the period in which the ON signal is output from the falling detection unit U1 and the period in which the turn signal applied to the gate of the transistor M2 through the diodes D5 and D6 has a high potential.

  When the output of the turn signal from the turn signal supply source V2 stops at the time c shown in the figure, the signal that passes through the diodes D5 and D6 and is given to the gate of the transistor M2 also becomes a low potential. At this time, the trailing edge detection unit U1 detects the last trailing edge of the turn signal, and outputs an ON signal from the output terminal until the predetermined period (0.6 s in this example) has elapsed. During this short period, the transistor M2 is turned on, the transistor M3 is turned off, and the transistor M1 is also turned off. Therefore, the state where the current supply to the light emitting elements D2 to D4 of the DRL is stopped is maintained.

  Thereafter, when an off signal is output from the output terminal of the falling detection unit U1 at the time d shown in the figure, the transistor M2 is turned off, thereby turning on the transistor M3 and turning on the transistor M1. A current is supplied to the light emitting elements D2 to D4.

  As shown in the partially enlarged view in FIG. 2, the signal passing through the diode D5 is a signal whose waveform falls slowly due to the action of the RC integration circuit including the resistor element R7 and the capacitor element C1. As a result, the rise timing of the ON signal output from the fall detection unit U1 and passing through the diode D1 is somewhat delayed with respect to the fall timing of the signal that passes through the diodes D5 and D6 and is applied to the gate of the transistor M2. Even in this case, the signal applied to the gate of the transistor M2 can be prevented from instantaneously becoming a high potential. That is, it is possible to avoid that the DRL is turned on instantaneously during this period.

  According to the embodiment as described above, the DRL can be turned off during the output of the turn signal, that is, during the operation of the turn lamp. Therefore, the visibility of the turn lamp attached to the DRL can be improved. It becomes. In addition, when the DRL and the turn lamp are also provided, the layout restriction is eliminated, so that the degree of freedom in designing the vehicular lamp can be increased.

  In addition, this invention is not limited to the content of embodiment mentioned above, In the range of the summary of this invention, it can change and implement variously. For example, in the above-described embodiment, a vehicle lamp configured to include a plurality of light emitting elements is exemplified as a control target. However, a vehicle lamp using a light source other than the light emitting elements (for example, a metal halide lamp) is illustrated. It may be controlled. Further, by applying the lighting control device of the present invention, the same lighting control can be performed even with a lighting specification lamp such as a DRL or a position lamp. The circuit configuration in the above-described embodiment is an example, and various alternative circuits can be used as long as an equivalent function can be realized. For example, the switch is not limited to a field effect transistor.

D1, D5, D6: Diodes D2, D3, D4: Light emitting elements (LEDs)
DRL: Daytime running lamp M1, M2, M3: Transistor (switching element)
R1, R2, R3, R4, R5, R6, R7: Resistance element C1: Capacitance element U1: Falling detection unit

Claims (4)

A device for controlling the lighting state of a vehicular lamp,
A switch connected between a power source and the vehicle lamp;
A switch control unit that controls the switch to an open state when an external input signal is a relatively high first potential, and controls the switch to a closed state when the input signal is relatively low;
A falling detection unit that supplies the signal of the first potential to the switch control unit for a predetermined period when the falling of the input signal from the outside is detected;
A lighting control device for a vehicular lamp. The predetermined period in which the signal of the first potential is supplied from the falling detection unit is set to be longer than a half cycle of the external input signal.
The lighting control device for a vehicular lamp according to claim 1. An RC integration circuit connected between the external input signal supply terminal and the switch control unit;
The lighting control device for a vehicular lamp according to claim 2. The lighting control device according to any one of claims 1 to 3,
A vehicular lamp controlled by the lighting control device;
A vehicle lamp system comprising:

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