JP2003347594A - Driver for semiconductor light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driver for a semiconductor light emitting element in which high class feeling is enhanced visually when an outer light system device or an illuminator in a vehicle employing the semiconductor light emitting element as a light source is unlighted. <P>SOLUTION: The driver (10) for a semiconductor light emitting element comprises a control section (20) and a drive section (30). Upon receiving a designation signal (S10) for unlighting the semiconductor light emitting elements (LEDS1, LEDS2), the control section (20) provides the drive section (30) with a control signal (S20) for shortening the time of applying a voltage to the semiconductor light emitting elements and lengthening the time of not applying the voltage gradually every specified period while repeating application and non-application of the voltage to the semiconductor light emitting elements alternately for a specified time interval thus applying no voltage to the semiconductor light emitting elements at the end of the specified time interval. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for a semiconductor light emitting element mounted on various vehicles including an automobile and the like, and more particularly, for example, a stop lamp, a tail lamp, a turn lamp, etc. The present invention relates to a driving device for a semiconductor light emitting element for driving a semiconductor light emitting element used as a light source in a lighting system device, for example, a vehicle lighting device such as a room lamp, a map lamp, a foot lamp, and the like.

[0002]

2. Description of the Related Art Generally, stop lamps for automobiles include:
An incandescent bulb (that is, an incandescent lamp) is used as a light source. An example of a drive device for turning on and off the incandescent bulb in this stop lamp will be described with reference to FIGS. 2A and 2B. As shown in FIG. 2A, in the driving device 1, the CPU (that is, Central)
Processing Unit 2 is a switch SW
A control signal S2 is supplied to the drive unit 3 in accordance with an instruction signal S1 indicating the ON / OFF state of No. 1 and the drive unit 3 executes application and non-application of the supply voltage Vb to the incandescent valves L1 and L2 in accordance with the control signal S2. . Note that the driving unit 3 includes a switching transistor Tr1 and a relay RE1.

FIG. 2B is a timing chart of a pulse voltage waveform of the instruction signal S1 and a pulse voltage waveform of the control signal S2. As shown in FIG. 2B, the instruction signal S
When 1 goes high, the CPU 2 outputs a control signal S2 at a high level, and when the instruction signal S1 goes low, the CPU 2 outputs a control signal S2 at a low level. .

When the control signal S2 applied to the base terminal (B) of the switching transistor Tr1 is at a high level, a current flows from the collector terminal (C) of the switching transistor Tr1 to the emitter terminal (E), and the power supply line 4, the current flows through the electromagnetic coil MC1 of the relay RE1, so that the switch RSW1
Is turned on. Therefore, power is supplied from the power supply line 4 to the incandescent valves L1 and L2, and the incandescent valves L1 and L2
Lights up.

When the control signal S2 applied to the base terminal (B) of the switching transistor Tr1 switches from the high level to the low level, a current flows between the collector terminal (C) and the emitter terminal (E) of the switching transistor Tr1. Does not flow, the switch RSW1 of the relay RE1 is turned off, and the incandescent valves L1 and L2 are turned off.

In recent years, in order to improve visibility,
Instead of an incandescent bulb, a light emitting diode (ie, LED
(Light Emitting Diode)) has been used as a light source in an external lighting system of a vehicle.

In the stop lamp described above, since an incandescent bulb is used, the lighting delay time from the supply of power to the incandescent bulb to the lighting is several tens of seconds.
It takes milliseconds (msec.). On the other hand, if a light-emitting diode with a high response speed is used for the stop lamp instead of the incandescent bulb, the lighting delay time is 1 millisecond or less, and therefore, the visual recognition time can be shortened, which greatly improves safety. Can contribute.

[0008]

However, although the lighting delay time can be shortened by using a light emitting diode,
Since the turn-off delay time from turning off the power supply to the light emitting diode to turning off the light is also reduced to 1 millisecond or less,
It is said that the luxury of the stop lamp when turned off, which does not directly affect safety, is visually lower than when an incandescent bulb is used. This is not limited to stop lamps, and in addition, for example, tail lamps, turn lamps, external lighting systems of vehicles including, and the like, and further, for example,
For in-vehicle lighting devices including room lamps, map lamps, foot lamps, etc., it is said that using an incandescent bulb as a light source is visually more preferable because the incandescent bulb has a longer turn-off delay time than a light-emitting diode. Have been done. That is, it is said that the incandescent bulb fades out light emission more slowly than the light emitting diode when the light is turned off.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to reduce the visual recognition time by making use of the characteristics of a semiconductor light-emitting element that has a fast rise at the time of lighting (ie, has a short lighting delay time). In addition, when the light is turned off, the light emission of the semiconductor light emitting element is slowly faded out like an incandescent bulb, so that the sense of quality of an external lighting system or a vehicle interior lighting device in which the semiconductor light emitting element is used as a light source can be visually recognized. An object of the present invention is to provide a driving device for a semiconductor light emitting device which is improved.

[0010]

In order to achieve the above-mentioned object, a driving apparatus for a semiconductor light-emitting device according to the present invention is provided with an instruction for turning on and off a semiconductor light-emitting device. A control unit that outputs a control signal in response to the instruction signal, and a driving unit that supplies power to the semiconductor light emitting element according to the control signal, the control unit includes:
Upon receiving an instruction signal for instructing lighting of the semiconductor light emitting element, the drive section outputs a control signal for applying a voltage to the semiconductor light emitting element, and the control section turns off the semiconductor light emitting element. When receiving an instruction signal to instruct,
The driving unit, for a predetermined period, the application and non-application of the voltage to the semiconductor light emitting element is alternately and repeatedly performed,
Control for gradually shortening the voltage application time to the semiconductor light emitting element and increasing the voltage non-application time for each fixed period, and performing non-voltage application to the semiconductor light emitting element at the end of the predetermined period Outputting a signal, thereby gradually turning off the semiconductor light emitting element.

According to the first aspect of the present invention, when the control unit of the semiconductor light emitting element driving device receives the instruction signal for instructing the semiconductor light emitting element to be turned off, the control unit instructs the driving unit to transmit the semiconductor light for a predetermined period. The voltage application and non-application to the light emitting element are alternately and repeatedly performed, and the voltage application time to the semiconductor light emitting element is gradually shortened and the voltage non-application time is lengthened gradually at regular intervals, and the predetermined period is set. At the end of the process, a control signal for causing no voltage to be applied to the semiconductor light emitting element is output. Therefore, the driving device for a semiconductor light emitting device of the present invention is effective in driving a semiconductor light emitting device in which the lighting delay time and the lighting delay time are shorter than that of the incandescent bulb. That is, when the control unit receives an instruction signal for instructing to turn off the semiconductor light emitting element, the semiconductor light emitting element driving device of the present invention does not immediately turn off the semiconductor light emitting element, and slowly turns off the semiconductor light like an incandescent bulb. Since the light emission of the light emitting element can be faded out, while utilizing the characteristics of the semiconductor light emitting element having a short lighting delay time, the elegance at the time of turning off the external lighting system of the vehicle or the lighting device in the vehicle using the semiconductor light emitting element is used. Can be visually similar to when an incandescent bulb is used.

Further, in the driving device for a semiconductor light emitting device according to the present invention, the predetermined period is at least 50 milliseconds.

According to the second aspect of the present invention, the predetermined period from when the driving unit receives the instruction signal for instructing to turn off the semiconductor light emitting element to when the semiconductor light emitting element is turned off is reduced to at least 50 milliseconds. Since the setting is made, the sense of quality at the time of turning off the external lighting system of the vehicle or the lighting device in the vehicle using the semiconductor light emitting element is not impaired.

According to a third aspect of the present invention, in the driving device for a semiconductor light emitting device, the predetermined period is set to 5 or less.
It is characterized in that it is set between 0 ms and 200 ms.

According to the third aspect of the present invention, the predetermined period from the time when the driving section receives the instruction signal for instructing to turn off the semiconductor light emitting element to the time when the semiconductor light emitting element is turned off is set to 5 times.
Since it is set between 0 and 200 milliseconds, it does not impair the sense of quality when turning off the external lighting system of the vehicle or the lighting device in the vehicle, in which the semiconductor light emitting device is used. The feeling of discomfort such as too long can be eliminated.

According to a fourth aspect of the present invention, there is provided a driving device for a semiconductor light emitting device, wherein the driving unit causes the driving unit to alternately repeat application and non-application of a voltage to the semiconductor light emitting device. The pulse period of the control signal is at most 10 milliseconds.

According to the fourth aspect of the present invention, the pulse period of the control signal for causing the drive section to alternately repeat the application and non-application of the voltage to the semiconductor light emitting element is set to at most 10 milliseconds. Therefore, it is possible to suppress the flicker of light emitted from the semiconductor light emitting element (ie, flicker) at the time of dimming (ie, at the time of fade-out of light emission).

According to a fifth aspect of the present invention, there is provided a driving device for a semiconductor light emitting device according to claim 5, wherein the driving unit alternately repeats application and non-application of a voltage to the semiconductor light emitting device. The pulse period of the control signal is set between 10 milliseconds and 1 millisecond.

According to the fifth aspect of the present invention, the pulse period of the control signal for causing the drive unit to alternately repeat the application and non-application of the voltage to the semiconductor light emitting element is set to 10 milliseconds to 1 millisecond. Since it is set in the middle, it is possible not only to suppress the flicker of light emission of the semiconductor light emitting element (ie, flicker) at the time of dimming (ie, at the time of fade-out of light emission), but also to realize a drive unit for high-speed switching by a control signal. Tracking stability can be secured.

The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading the embodiments of the invention described below with reference to the accompanying drawings.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below in detail with reference to the drawings. FIG. 1A is a diagram showing a circuit configuration of a driving device for a semiconductor light emitting device of the present invention for driving a semiconductor light emitting device, and FIG.
(A) The pulse voltage waveform of the instruction signal S10 and the control signal S
20 is a timing chart of 20 pulse voltage waveforms.

In FIG. 1A, as an example of a semiconductor light emitting device driven by the semiconductor light emitting device driving device 10 of the present invention, current limiting resistors R1 and R2 are provided between an element driving line 50 and a ground G. A plurality of light emitting diodes LEDS1 (LEDa, LEDa) electrically connected in parallel through
b, LEDc), LEDs2 (LEDd, LEDe, L
Although EDf) is shown, the number of semiconductor light emitting elements is not limited to a plurality but may be one. That is, the number of the semiconductor light emitting elements is appropriately determined according to the application and the specification. For example, when one light emitting diode is used, the light emitting diode may be electrically connected between the element drive line 50 and the ground G via a current limiting resistor.

The current limiting resistors (the current limiting resistors R1 and R2 in FIG. 1A) are connected to the semiconductor light emitting device (FIG. 1A).
Is a resistor for limiting the current flowing to the light emitting diodes LEDS1 and LEDS2), but may not be provided depending on the semiconductor light emitting element used. Of course, when using a semiconductor light emitting element with a built-in current limiting resistor, it goes without saying that no current limiting resistor is required.

The semiconductor light emitting device driving device 10 controls the power supply to the light emitting diodes LEDS1 and LEDS2, thereby controlling the light emitting diodes LEDS1 and LEDS2.
2 (i.e., turn on and off). The driving device 10 for a semiconductor light emitting element includes a light emitting diode LE.
A driving unit 30 that supplies power to DS1 and LEDs2 and drives the light emitting diodes LEDs1 and LEDs2.
And the light emitting diodes LEDS1,
And a control unit 20 for controlling power supply to the LEDS2.

The control section 20 is electrically connected to the drive section 30. The control unit 20 includes a light emitting diode LEDS
1, a switch S for turning on and off the LEDS2
A control signal S20 is output in response to an instruction signal S10 indicating the ON / OFF state of W10, and the control signal S20 is supplied to the drive unit 30 to act as a controller that controls the operation of the drive unit 30. The control unit 20 includes, for example, a CPU
And a processing circuit that outputs a control signal S20 in response to the input of the instruction signal S10.

As shown in FIG. 1 (B), low (Lo)
When the pulse voltage waveform of the instruction signal S10 that switches from the w) level to the high level rises, the control unit 20 outputs the control signal S20 of the high level and outputs the light emitting diodes LEDS1, LED to the driving unit 30.
Power supply to S2 (ie, light emitting diodes LEDS1,
LEDS2 lighting operation). That is, the control unit 2
When 0 receives an instruction signal S10 for instructing lighting of the light emitting diodes LEDS1 and LEDS2, it outputs a control signal S20 for causing the drive unit 30 to apply a voltage to the light emitting diodes LEDS1 and LEDS2.

On the other hand, when the pulse voltage waveform of the instruction signal S10 that switches from the high level to the low level falls,
The control unit 20 simply includes the light emitting diodes LEDS1, LED
Instead of outputting a control signal for causing the drive unit 30 to perform the light-off operation of S2, the light emitting diodes LEDS1 and LEDS1 are not output.
A control signal S20 is output to cause the drive unit 30 to perform a plurality of stages of dimming operations in which the brightness of S2 is gradually darkened periodically and finally turned off.

Specifically, the control unit 20 controls the instruction signal S10
When the pulse voltage waveform is switched from the high level to the low level, a control signal S20 having a pulse voltage waveform that alternates between a high level and a low level for a predetermined period is output. At this time, the control unit 20 outputs the control signal S
The pulse width of the drive unit 30 at the high level is gradually reduced and the pulse width at the low level is gradually increased, and the control signal S20 becomes constant at the low level at the end of the predetermined period. Control (that is, pulse width modulation control) is performed.

That is, the control unit 20 controls the light emitting diode LE
Upon receiving an instruction signal S10 for instructing DS1 and LEDS2 to be turned off, the driving unit 30 alternately repeats application and non-application of voltage to the light emitting diodes LEDS1 and LEDS2 for a predetermined period, and The voltage application time to the light emitting diodes LEDS1, LEDS2 is gradually shortened and the voltage non-application time is gradually increased, and at the end of the predetermined period, the light emitting diodes LEDS1, LES
A control signal S20 for causing non-application of a voltage to DS2 is output.

As described above, the semiconductor light emitting device driving device 10 of the present invention comprises the light emitting diodes LEDS1 and LEDS2.
When the control unit 20 receives the instruction signal S10 for instructing to turn off the LEDs, the light emitting diodes LEDS1 and LEDS2 are not immediately turned off, but the light emission of the light emitting diodes LEDS1 and LEDS2 is faded out slowly like an incandescent bulb (ie, (Light emission amount can be gradually reduced), so that the light emitting diodes LEDS1, L
Light emitting diode LEDS while utilizing the characteristics of EDS2
1, when the external lighting system of the vehicle using the LEDS2 or the lighting device inside the vehicle is turned off, the elegance can be made visually the same as when the incandescent bulb is used.

In FIG. 1B, the predetermined period is set to 80
Milliseconds (msec.), And the pulse period of the control signal S20 in the predetermined period is set to 10 milliseconds (that is, PW
M drive frequency is set to 100 Hz, and the above-mentioned constant period is twice as long as the pulse period of the control signal S20 (ie, 20 milliseconds).
Is set. Therefore, in this example, 8
During 0 ms, the control unit 20 outputs a control signal S20 in which the duty ratio between the high-level pulse width and the low-level pulse width gradually changes every 20 milliseconds, and finally becomes a low-level constant. ing. Although FIG. 1B shows an example in which the above-mentioned fixed period is twice as long as the pulse period of the control signal S20, the present invention is not limited to this. It may be three times or more.

Incidentally, in order to suppress the flickering (ie, flicker) of the light emission of the light emitting diodes LEDS1 and LEDS2 at the time of dimming (ie, at the time of light emission fade-out),
It is desirable that the PWM drive frequency of the control unit 20 be set to at least 100 Hz. In other words, the control signal S for causing the drive unit 30 to alternately repeat the application and non-application of the voltage to the light emitting diodes LEDs1 and LEDs2.
Preferably, the 20 pulse periods are set to at most 10 milliseconds.

The light emitting diodes LEDS1 and LEDS2 at the time of dimming (that is, at the time of fading out of light emission)
The PWM drive frequency of the control unit 20 is set to 100 Hz to 1 KHz in order to not only suppress the flickering of light emission (i.e., flicker), but also to ensure the stability of the drive unit 30 following high-speed switching by the control signal S20. It is desirable to set. In other words, the control signal S2 for causing the drive unit 30 to alternately repeat the application and non-application of the voltage to the light emitting diodes LEDs1 and LEDs2.
It is preferable that the pulse period of 0 is set between 10 ms and 1 ms.

Further, the light emitting diodes LEDS1, LED
When the drive unit 30 receives an instruction signal S10 for instructing the light-emitting diodes LEDS1 and LEDS2 to be turned off in order to obtain a visual luxury when the external lighting system of the vehicle or the vehicle interior lighting device using S2 is turned off. It is desirable to set a predetermined period from turning off the light emitting diodes LEDS1 and LEDS2 to at least 50 milliseconds.
Furthermore, in order to eliminate a sense of incongruity that the light-off delay time of the light emitting diodes LEDS1 and LEDS2 is too long,
It is desirable to set the above-mentioned predetermined period to 50 milliseconds to 200 milliseconds.

That is, the time from the start of dimming to turning off is set to 50.
Light emitting diode LED with millisecond to 200 millisecond setting
It is preferable to make the light emission of S1 and LEDS2 fade out slowly.

The desired set values are all preset in the control unit 20. However, all the set values are recorded and the setting value storage EEP-ROM which allows the control unit 20 to change the various set values is set. ROM (that is, Electric
all Erasable Program
Able-Read Only Memory may be provided separately or integrally with the control unit 20.

Next, the configuration of the driving section 30 will be described in detail. The drive unit 30 is electrically connected to the power supply line 40 and the element drive line 50, and receives a control signal S from the control unit 20.
20 the supply voltage Vb to the current limiting resistors R1 and R2
Of light emitting diode LEDS
1, LEDS2 is turned on and off. This drive unit 3
Reference numeral 0 includes a switching transistor Tr10 and a semiconductor relay SRE1 for high-speed switching by PWM driving.

The base terminal (B) of the switching transistor Tr10 is electrically connected to the control unit 20 and receives a control signal S20. The emitter terminal (E) of the switching transistor Tr10 is electrically connected to the ground (G). In this embodiment, an NPN-type bipolar transistor is used as an example of the switching transistor Tr10 as shown in FIG. 1A, but a PNP-type bipolar transistor, a MOSFET, or the like may be used as appropriate. . Further, depending on the type of the switching transistor Tr10 used, the instruction signal S10 and the control signal S20 are appropriately set.
May be inverted.

The semiconductor relay SRE1 has a switching power transistor Q1. The gate terminal (G) of the switching power transistor Q1 is electrically connected to the collector terminal (C) of the switching transistor Tr10, the drain terminal (D) is electrically connected to the power supply line 40, and the source terminal (S ) Is the element drive line 5
0 is electrically connected. Furthermore, semiconductor relay SR
E1 is provided with a resistor R3 as required.

In this embodiment, the resistor R3 is connected to the gate terminal (G) of the switching power transistor Q1 and the collector terminal (C) of the switching transistor Tr10.
And a power supply line 40. The high-level control signal S20 is supplied from the control unit 20 to the base terminal (B) of the switching transistor Tr10.
When 0 is turned on, the collector terminal (C) to the emitter terminal (E) of the switching transistor Tr10.
Is supplied from the power supply line 40.

In this embodiment, as an example of the switching power transistor Q1, a P-channel type power MOSFET is used as shown in FIG.
In addition, an N-channel power MOSFET (using a charge pump), a bipolar transistor, or the like may be used as appropriate. Further, the instruction signal S1 is appropriately set according to the type of the switching power transistor Q1 used.
0 or the phase of the control signal S20 may be inverted.

Now, the switching transistor Tr10
Is a control signal S20 applied to the base terminal (B).
Is high level, the switching transistor Tr1
0 from the collector terminal (C) to the emitter terminal (E).
3, the potential of the gate terminal (G) of the switching power transistor Q1 becomes low level, and the switching power transistor Q1 is turned on. Therefore, a potential substantially equal to the supply voltage Vb is generated in the element drive line 50, and a current flows through the light emitting diodes LEDS1 and LEDS2 via the current limiting resistors R1 and R2, so that the light emitting diodes LEDS1 and LEDS2 emit light.

On the other hand, the switching transistor Tr10
When the control signal S20 applied to the base terminal (B) becomes low level, no current flows between the collector terminal (C) and the emitter terminal (E) of the switching transistor Tr10. The potential of the terminal (G) becomes substantially equal to the supply voltage Vb, and the switching power transistor Q1 is turned off.
F state, the light emitting diodes LEDs1 and LEDs2
Turns off.

Although the semiconductor light emitting device driving device 10 according to one embodiment of the present invention has been described above, the present invention is effective for driving a semiconductor light emitting device having a lighting delay time and a light emitting delay time shorter than that of an incandescent bulb. It is a target. For example, the present invention is applied to an external lighting system of a vehicle such as a stop lamp, a tail lamp, a turn lamp, and the like, and a driving device of a semiconductor light emitting element used as a light source for a vehicle interior lighting device such as a room lamp, a map lamp, and a foot lamp. By applying the invention, excellent effects can be obtained. In particular, since the stop lamp is frequently turned on and off during vehicle operation, the effect of the present invention is enormous.

It should be noted that the present invention is not limited to the above-described embodiment, but can be appropriately modified and improved. In addition, the shape, form, number, location, and the like of each component in the above-described embodiment are arbitrary and not limited as long as the present invention can be achieved. Although the specific set values of the predetermined period and the pulse period (that is, the PWM drive frequency) are exemplified as described above, the external lighting system or the vehicle interior lighting device (that is, the vehicle interior lighting device in which the semiconductor light emitting element is used as the light source) Depending on the type of the lamp, the above-mentioned set values may be appropriately changed to other set values so as to obtain a high-grade feeling when the lights are turned off.

The instruction signal S10 and the control signal S20 are not limited to rectangular waves as shown in FIG.
At least one of 10 and the control signal S20 may be, for example, a triangular wave, a sawtooth wave, or the like. In the above-described embodiment, one instruction signal S10 having a pulse voltage waveform formed by a potential difference between a high level and a low level is used, but the present invention is not limited to this. Instead of the instruction signal S10, for example, two types of logic signals are input to the control unit 20, and the control unit 20 determines the ON / OFF state of the switch SW10 based on the logic signals. May be generated.

[0047]

As described above, according to the present invention, when the control unit of the semiconductor light emitting element driving device receives the instruction signal for instructing the semiconductor light emitting element to be turned off, the control unit transmits the predetermined signal to the driving unit. During the period, the application and non-application of the voltage to the semiconductor light emitting element are alternately and repeatedly performed, and the application time of the voltage to the semiconductor light emitting element is gradually shortened and the non-application time of the voltage is gradually increased at regular intervals, and At the end of the predetermined period, a control signal for causing no voltage to be applied to the semiconductor light emitting element is output. Therefore, the driving device for a semiconductor light emitting device of the present invention is effective in driving a semiconductor light emitting device in which the lighting delay time and the lighting delay time are shorter than that of the incandescent bulb.
That is, when the control unit receives an instruction signal for instructing to turn off the semiconductor light emitting element, the semiconductor light emitting element driving device of the present invention does not immediately turn off the semiconductor light emitting element. Since the light emission of the light emitting element can be faded out, while utilizing the characteristics of the semiconductor light emitting element having a short lighting delay time, the elegance at the time of turning off the external lighting system of the vehicle or the lighting device in the vehicle using the semiconductor light emitting element is used. Can be visually similar to when an incandescent bulb is used.

Further, according to the present invention, the predetermined period from when the driver receives the instruction signal for instructing to turn off the semiconductor light emitting element to when the semiconductor light emitting element is turned off is set to at least five times.
Since it is set to 0 milliseconds, the sense of quality at the time of turning off the external lighting system of the vehicle or the lighting device in the vehicle using the semiconductor light emitting element is not impaired.

Further, according to the present invention, the predetermined period from when the driving unit receives the instruction signal for instructing to turn off the semiconductor light emitting element to when the semiconductor light emitting element is turned off is set to 50 to 200 milliseconds. Since it is set to, it does not impair the luxury feeling when the external lighting system of the vehicle or the vehicle interior lighting device in which the semiconductor light emitting element is used is turned off, and also eliminates the uncomfortable feeling that the light-off delay time is too long. it can.

Further, according to the present invention, the pulse period of the control signal for causing the driving section to alternately apply and not apply the voltage to the semiconductor light emitting element is set to at most 10 milliseconds. In addition, it is possible to suppress a flicker of light emitted from the semiconductor light emitting element (ie, flicker) at the time of dimming (that is, at the time of fading out of light).

Further, according to the present invention, the pulse period of the control signal for causing the drive unit to alternately repeat the application and non-application of the voltage to the semiconductor light emitting element is set to 10 milliseconds to 1 millisecond.
Since the setting is performed in milliseconds, it is possible not only to suppress the flickering (ie, flicker) of the light emission of the semiconductor light emitting element at the time of dimming (ie, at the time of light emission fading), but also to perform high-speed switching by a control signal. , The following stability of the drive unit can be secured.

[Brief description of the drawings]

1A is a diagram showing a circuit configuration of a semiconductor light emitting device driving device of the present invention for driving a semiconductor light emitting device, and FIG. 1B is a diagram showing a pulse voltage waveform of an instruction signal and a pulse voltage waveform of a control signal. 6 is a timing chart of FIG.

FIG. 2A is a diagram showing an example of a conventional drive device for turning on and off an incandescent bulb of a stop lamp for an automobile, and FIG. 2B is a timing chart of a pulse voltage waveform of an instruction signal and a pulse voltage waveform of a control signal. It is a chart.

[Explanation of symbols]

Reference Signs List 10 drive device for semiconductor light emitting device 20 control unit 30 drive unit 40 power supply line 50 element drive line S10 instruction signal S20 control signal LEDs1, LEDs2 light emitting diode (semiconductor light emitting device) Tr10 switching transistor SRE1 semiconductor relay Q1 switching power transistor

Claims (5)

[Claims] A control unit that outputs a control signal in response to an instruction signal for instructing turning on and off of the semiconductor light emitting element; and a driving unit that supplies power to the semiconductor light emitting element in accordance with the control signal. When the control unit receives an instruction signal for instructing lighting of the semiconductor light emitting element, the control unit outputs a control signal for applying a voltage to the semiconductor light emitting element to the driving unit, and Upon receiving an instruction signal for instructing turning off of the semiconductor light emitting element, the driving unit causes the drive unit to alternately repeat application and non-application of a voltage to the semiconductor light emitting element for a predetermined period, and at regular intervals. The voltage application time to the semiconductor light emitting element is gradually shortened, the voltage non-application time is lengthened, and the voltage is not applied to the semiconductor light emitting element at the end of the predetermined period. Outputs a signal, whereby said semiconductor light emitting element driving apparatus characterized by gradually turning off the semiconductor light-emitting element. 2. The driving device for a semiconductor light emitting device according to claim 1, wherein the predetermined period is at least 50 milliseconds. 3. The method according to claim 2, wherein the predetermined period is between 50 milliseconds and 20 milliseconds.
3. The driving device for a semiconductor light emitting device according to claim 1, wherein the driving time is set within 0 ms. 4. A pulse cycle of the control signal when the drive section alternately repeats application and non-application of a voltage to the semiconductor light emitting element is at most 10 milliseconds. The driving device for a semiconductor light emitting device according to any one of claims 1 to 3. 5. A pulse cycle of the control signal when the drive section alternately repeats application and non-application of a voltage to the semiconductor light emitting element is set to be between 10 milliseconds and 1 millisecond. The driving device for a semiconductor light emitting device according to any one of claims 1 to 4, wherein: