Light source device and method for controlling the lighting of the light source device

Abstract

The present invention provides a light source device and a method for controlling the lighting of the light source device that can suppress inrush current during alternating flashing. [Solution] The light source device comprises a first light source unit including a first LED, a second light source unit including a second LED, a constant current power supply unit that supplies power to the first and second light source units, an acquisition unit that acquires an external signal from the outside when a predetermined event occurs, and a control unit that, when the acquisition unit acquires an external signal, opens and closes the circuits between the constant current power supply unit and the first and second light source units to alternately light up the first and second light source units. The control unit lights up the first and second light source units simultaneously for a predetermined time when alternating between lighting up the first and second light source units.

Description

Technical Field

[0001] The present invention relates to a light source device and a lighting control method for the light source device.

Background Art

[0002] As a light source of a light source device such as a lighting device or a display device, in addition to an incandescent lamp, a discharge lamp, etc., an LED is widely used. Also, by blinking the light source of the light source device, the applications for alerting in case of abnormalities are expanding.

[0003] Patent Document 1 discloses a device that can detect a failure of a light source by turning off one of two light sources while the other is lit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When an LED is used as a light source, a constant current power source is generally used as a power source for supplying power to the LED. In this case, when two LEDs are alternately blinked and a state where neither of the two LEDs is lit occurs, the constant current power source becomes a no-load state, and when one LED is lit, an excessive inrush current flows through the LED, and the LED may be damaged.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a light source device and a lighting control method for the light source device that can suppress an inrush current during alternate blinking.

Means for Solving the Problems

[0007] The present invention includes multiple means for solving the above problems, but to give one example, the light source device comprises a first light source unit including a first LED, a second light source unit including a second LED, a constant current power supply unit that supplies power to the first and second light source units, an acquisition unit that acquires an external signal from the outside when a predetermined event occurs, and a control unit that, when the acquisition unit acquires an external signal, opens and closes the electrical circuits between the constant current power supply unit and the first and second light source units to alternately light up the first and second light source units, wherein the control unit lights up the first and second light source units simultaneously for a predetermined time when alternating between lighting up the first and second light source units. [Effects of the Invention]

[0008] According to the present invention, inrush current during alternating flashing can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of the configuration of the lighting device according to this embodiment. [Figure 2] This figure shows an example of lighting control for a lighting device. [Figure 3] This figure shows an example of alternating flashing in a comparative example. [Figure 4] This diagram schematically shows the voltage and current of a constant current power supply under no-load conditions. [Figure 5] This figure shows an example of alternating flashing of a lighting device. [Figure 6] This figure shows an example of the evaluation results for a lighting device. [Modes for carrying out the invention]

[0010] The present invention will be described below based on the drawings illustrating embodiments. Figure 1 is a diagram showing an example of the configuration of the lighting device 100 of this embodiment. The lighting device 100, as a light source device, includes a detection circuit 10, a constant current power supply unit 20, a control circuit 30, a switching circuit 40, a first light source unit 50, and a second light source unit 60, etc. The lighting device 100 includes terminals P1, P2, and P3. Commercial power (AC 100~242V) is connected to terminals P1 and P2, and AC power from the commercial power supply is supplied to the constant current power supply unit 20 via terminals P1 and P2.

[0011] The constant current power supply unit 20 includes an AC / DC conversion circuit that converts the input AC power into DC power and supplies the converted DC power to the first light source unit 50 and the second light source unit 60 via the switching circuit 40. The constant current power supply unit 20 performs constant current control so that the current supplied to the first light source unit 50 and the second light source unit 60 is a predetermined value.

[0012] The switching circuit 40 includes a switching element 41 that opens and closes the circuit between the constant current power supply unit 20 and the first light source unit 50, and a switching element 42 that opens and closes the circuit between the constant current power supply unit 20 and the second light source unit 60. The switching elements 41 and 42 may be, for example, mechanical contacts of a relay or semiconductor switches of an SSR (solid state relay). Furthermore, the switching between the first light source unit 50 and the second light source unit 60 may be double-pole or single-pole.

[0013] The first light source unit 50 has multiple white LEDs arranged in series. In this embodiment, 44 white LEDs are arranged in series, but the arrangement of the white LEDs is not limited to this, and multiple white LEDs arranged in series may be connected in parallel. The forward voltage of the first light source unit 50 is, for example, 118V, but is not limited to this.

[0014] The second light source unit 60 has multiple colored LEDs other than white LEDs arranged in series. In this embodiment, 48 red LEDs are arranged in series, but the arrangement of the red LEDs is not limited to this, and multiple series-arranged red LEDs may be connected in parallel. The forward voltage of the second light source unit 60 is, for example, 87V, but is not limited to this. Furthermore, it is not limited to red LEDs, and other colors other than white may be used.

[0015] The detection circuit 10 functions as an acquisition unit and acquires an external signal from an external device (e.g., an alarm panel) via terminal P3. The external device is equipped with a sensor. This sensor can detect abnormal situations in the surroundings, and when the sensor detects an abnormal situation (a predetermined event), the external device outputs an external signal. When the detection circuit 10 acquires an external signal, it outputs an abnormal signal to the control circuit 30; when it does not acquire an external signal, it outputs a normal signal to the control circuit 30.

[0016] The control circuit 30 functions as a control unit and, when it receives an abnormal signal, controls the constant current power supply unit 20 and the switching circuit 40 to alternately light up the first light source unit 50 and the second light source unit 60. When the control circuit 30 receives a normal signal, it controls the constant current power supply unit 20 and the switching circuit 40 to light up only the first light source unit 50 and turn off the second light source unit 60.

[0017] As described above, the lighting device 100 (light source device) includes a first light source unit 50 including a first LED, a second light source unit 60 including a second LED, a constant current power supply unit 20 that supplies power to the first light source unit 50 and the second light source unit 60, a detection circuit 10 that acquires an external signal from the outside when a predetermined event occurs, and a control circuit 30 that, when the detection circuit 10 acquires an external signal, opens and closes the electrical circuits between the constant current power supply unit 20 and the first light source unit 50 and the second light source unit 60 respectively to alternately light up the first light source unit 50 and the second light source unit 60.

[0018] FIG. 2 is a diagram showing an example of lighting control of the lighting device 100. As shown in FIG. 2, when the external signal is off (that is, when the control circuit 30 acquires a normal signal from the detection circuit 10), only the first light source unit 50 is lit (on), and the second light source unit 60 is turned off (off).

[0019] Next, when the external signal changes from off to on (that is, when the control circuit 30 acquires an abnormal signal from the detection circuit 10), the first light source unit 50 changes from being lit (on) to being turned off (off), and the second light source unit 60 changes from being turned off (off) to being lit (on). At this time, as shown in FIG. 2, the state in which the first light source unit 50 is lit and the state in which the second light source unit 60 is lit overlap for a time d.

[0020] After the first light source unit 50 is turned off and the second light source unit 60 is lit for a predetermined time, the first light source unit 50 changes from being turned off (off) to being lit (on), and the second light source unit 60 changes from being lit (on) to being turned off (off). At this time, as shown in FIG. 2, the state in which the first light source unit 50 is lit and the state in which the second light source unit 60 is lit overlap for a time d.

[0021] After the first light source unit 50 is lit and the second light source unit 60 is turned off for a predetermined time, the first light source unit 50 changes from being lit (on) to being turned off (off), and the second light source unit 60 changes from being turned off (off) to being lit (on). At this time, as shown in FIG. 2, the state in which the first light source unit 50 is lit and the state in which the second light source unit 60 is lit overlap for a time d. Thereafter, the same operation is repeated.

[0022] As described above, when the control circuit 30 alternately lights the first light source unit 50 and the second light source unit 60, the control circuit 30 lights the first light source unit 50 and the second light source unit 60 simultaneously for a predetermined time (simultaneous lighting time d). Thereby, the inrush current at the time of alternate flashing can be suppressed.

[0023] Next, an explanation will be given of the fact that the inrush current flowing through the LED can be suppressed by lighting simultaneously for the simultaneous lighting time d.

[0024] Figure 3 shows an example of alternating flashing in the comparative example. As shown in Figure 3, relay contacts are provided in the circuits between the constant current power supply and the white LED and the colored LED, respectively, allowing the white LED and the colored LED to be lit alternately. In the comparative example, at time t1, the contacts in the circuit between the constant current power supply and the white LED are closed, and the contacts in the circuit between the constant current power supply and the colored LED are open, so the white LED is lit and the colored LED is off.

[0025] At time t2, when the white LED is switched from on to off and the colored LED is switched from off to on, a switching time (e.g., several ms) is required for the contacts in the circuit between the constant current power supply and the colored LED to switch from an open state to a closed state. As a result, both the circuit between the constant current power supply and the white LED, and the circuit between the constant current power supply and the colored LED, become open. Therefore, the output of the constant current power supply becomes unloaded.

[0026] At time t3, the contacts in the circuit between the constant current power supply and the colored LEDs close, causing the white LEDs to turn off and the colored LEDs to light up.

[0027] Figure 4 schematically shows the voltage and current of a constant current power supply under no-load conditions. As explained in Figure 3, at time t2, the system becomes no-load, so the output voltage of the constant current power supply increases rapidly. On the other hand, since there is no load, the output current of the constant current power supply is 0 (zero). At time t3, when the contacts of the circuit between the constant current power supply and the colored LED close, the rapidly increased voltage is applied to the colored LED, causing an excessive inrush current to flow through the colored LED. If the inrush current exceeds the rated current of the colored LED, the colored LED may be damaged. Note that the voltage and current waveforms shown in Figure 4 are schematic and may differ from the actual waveforms.

[0028] Figure 5 shows an example of alternating flashing of the lighting device 100. At time t1, the switching element 41 is in the closed state, the switching element 42 is in the open state, the first light source unit 50 is lit, and the second light source unit 60 is off.

[0029] At time t2, when the first light source unit 50 is turned off from the on state and the second light source unit 60 is turned on from the off state, the switching element 41 is kept in the closed state until the switching element 42 moves from the open state to the closed state, and a time is provided for each of the switching elements 41 and 42 to remain in the closed state. In this state, both the first light source unit 50 and the second light source unit 60 are lit. The output side of the constant current power supply unit 20 does not become unloaded.

[0030] The control circuit 30 can prevent the output of the constant current power supply unit 20 from becoming unloaded by providing a simultaneous lighting time. This suppresses the inrush current during alternating flashing.

[0031] At time t3, the switching element 41 is in the open state. As a result, the first light source unit 50 turns off from the lit state, and the second light source unit 60 turns on from the off state. The same operation is repeated thereafter.

[0032] Figure 6 shows an example of the evaluation results of the lighting device 100. As shown in Figure 6, the first light source unit 50 has a configuration in which 44 white LEDs are connected in series, and the forward voltage is 118V. The second light source unit 60 has a configuration in which 48 red LEDs are connected in series, and the forward voltage is 87V. The blinking period of the first light source unit 50 and the second light source unit 60 is 600ms, specifically the on time is 670ms, the off time is 600ms, and the simultaneous on time is 35ms.

[0033] In the comparative example, the inrush current flowing through the red LED when switching from a white LED to a red LED was 1083mA. In contrast, in this embodiment, it was 875mA, a reduction of approximately 20% in inrush current. Assuming the maximum rated pulse current of the red LED is 1000mA, this embodiment can suppress the inrush current to below the rated current.

[0034] The simultaneous lighting time can be determined as follows, for example. As described in FIG. 3, assuming that the switching time required for switching the switching element that opens and closes the circuit between the constant current power supply unit and the light source unit is T1 (ms), in order to avoid the output side of the constant current power supply unit being in a no-load state, the simultaneous lighting time d needs to satisfy d > T1. The time T1 is, for example, about 2 ms.

[0035] Also, as described in FIG. 4, the inrush current can have a steep vibration waveform. Assuming that the time required for the inrush current to become less than or equal to the maximum rated pulse current of the LED is T2 (> T1), more preferably, the simultaneous lighting time d should satisfy d > T2. The time T2 depends on the characteristics of the constant current power supply unit and the characteristics of the LED, but is, for example, about 10 to 30 ms.

[0036] On the other hand, when the simultaneous lighting time d becomes long, there is a problem with the visibility of the alternating lighting, and there is a possibility that it can be visually recognized that both color LEDs are lit simultaneously. Assuming that the time without a problem with the visibility of the alternating lighting is T3, it is preferable that the simultaneous lighting time d satisfies d < T3. The time T3 is, for example, about 50 ms.

[0037] Therefore, the simultaneous lighting time d can be set as T2 < d < T3. For example, if T2 = 10 ms, then 10 ms < d < 50 ms can be set. More preferably, if T2 = 30 ms, then 30 ms < d < 50 ms can be set.

[0038] When performing alternating lighting, if the forward voltages of the white LED of the first light source unit 50 and the colored LED of the second light source unit 60 are different, and when switching from the lighting state of the LED with the higher forward voltage to the lighting state of the LED with the lower forward voltage, the inrush current becomes large. Therefore, when grasping the state of the inrush current, it is necessary to consider the state of switching from the lighting state of the LED with the higher forward voltage to the lighting state of the LED with the lower forward voltage. Also, in order to suppress the inrush current, the forward voltages of the LEDs in both light source units may be made approximately the same.

[0039] Generally, when installing lighting equipment in factories or offices, multiple lighting devices 100 are often installed over a relatively wide area. In such cases, the multiple lighting devices 100 can be divided into a master unit and multiple slave units connected to the master unit, and a synchronization circuit for alternating flashing can be provided between the master unit and the slave units. The synchronization circuit of the master unit transmits a periodic signal for alternating flashing to each slave unit. The slave units can then perform alternating flashing in synchronization with the received synchronization signal.

[0040] As described above, according to this embodiment, when multiple light sources are alternately flashed using a single constant current power supply, the output side of the constant current power supply can be kept unloaded by simultaneously lighting up the multiple light sources for a predetermined time, thereby suppressing the inrush current during alternate flashing.

[0041] Furthermore, according to this embodiment, since power can be supplied to multiple light sources with a single constant current power supply unit, the cost of power supply can be reduced.

[0042] (Note 1) The light source device comprises a first light source unit including a first LED, a second light source unit including a second LED, a constant current power supply unit that supplies power to the first and second light source units, an acquisition unit that acquires an external signal from the outside when a predetermined event occurs, and a control unit that, when the acquisition unit acquires an external signal, opens and closes the circuits between the constant current power supply unit and the first and second light source units to alternately light up the first and second light source units, wherein the control unit lights up the first and second light source units simultaneously for a predetermined time when alternating between lighting up the first and second light source units.

[0043] (Note 2) In the light source device, as described in Note 1, the first LED is a white LED, and the second LED is a colored LED other than white.

[0044] (Note 3) In the light source device, as described in Note 1 or Note 2, if the control unit does not acquire an external signal with the acquisition unit, it lights up only the first light source unit.

[0045] (Note 4) In any one of Notes 1 to 3, the light source device is configured such that the control unit avoids the output of the constant current power supply unit becoming unloaded by providing the simultaneous lighting time.

[0046] (Note 5) The method for controlling the lighting of a light source device comprises a first light source unit including a first LED, a second light source unit including a second LED, a constant current power supply unit that supplies power to the first and second light source units, an acquisition unit that acquires an external signal from the outside when a predetermined event occurs, and a control unit that, when the acquisition unit acquires an external signal, opens and closes the electrical circuits between the constant current power supply unit and the first and second light source units to alternately light up the first and second light source units, wherein when the first and second light source units are alternately lit, the first and second light source units are lit simultaneously for a predetermined time.

[0047] The matters described in each embodiment can be combined with each other. Furthermore, the independent and dependent claims described in the claims can be combined with each other in any combination, regardless of the form of reference. In addition, the claims use a form in which claims referencing two or more other claims (multi-claim form), but are not limited to this. A form in which multi-claims referencing at least one multi-claim (multi-multi-claim) may also be used. [Explanation of Symbols]

[0048] 10 Detection circuit 20 Constant current power supply section 30 Control circuits 40 Switching Circuit 41, 42 Switching elements 50 1st light source section 60 Second light source section

Claims

1. A first light source unit including a first LED, A second light source unit including a second LED, A constant current power supply unit that supplies power to the first light source unit and the second light source unit, An acquisition unit that acquires an external signal from an external source when a predetermined event occurs, When the acquisition unit acquires an external signal, the control unit opens and closes the circuit between the constant current power supply unit and the first light source unit and the second light source unit, respectively, to alternately light up the first light source unit and the second light source unit. Equipped with, The control unit, When the first light source and the second light source are alternately lit, the first light source and the second light source are lit simultaneously for a predetermined period of time. Light source device.

2. The first LED is a white LED, and the second LED is a colored LED other than white. The light source device according to claim 1.

3. The control unit, If the acquisition unit does not acquire an external signal, only the first light source unit is illuminated. A light source device according to claim 1 or claim 2.

4. The control unit, By providing the aforementioned simultaneous lighting time, the output of the constant current power supply unit will not be left unloaded. A light source device according to claim 1 or claim 2.

5. A first light source unit including a first LED, A second light source unit including a second LED, A constant current power supply unit that supplies power to the first light source unit and the second light source unit, An acquisition unit that acquires an external signal from an external source when a predetermined event occurs, When the acquisition unit acquires an external signal, the control unit opens and closes the circuit between the constant current power supply unit and the first light source unit and the second light source unit, respectively, to alternately light up the first light source unit and the second light source unit. A method for controlling the lighting of a light source device comprising: When the first light source and the second light source are alternately lit, the first light source and the second light source are lit simultaneously for a predetermined period of time. A method for controlling the illumination of a light source device.

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