JP5452539B2 - Light source lighting device and lighting fixture - Google Patents

Description

  The present invention relates to a light source lighting device and a lighting fixture.

  Conventionally, a highly efficient DC / DC converter circuit system has been used for a light emitting diode (LED) lighting device. For example, a flyback converter or a step-down chopper circuit is used as the DC / DC converter, and a stable current can be supplied to the LED by constant current control.

  By the way, in the lighting device for lighting the LED, it is necessary to detect the abnormality of the output voltage when the LED is broken or short-circuited, and to safely stop the operation of the lighting device. Therefore, there is an output voltage detection unit that reduces the output voltage when the output voltage rises (for example, see Patent Document 1), and a technique for detecting the presence or absence of a short circuit failure of the LED by output voltage detection (for example, Patent Document 2).

JP 2006-222376 A JP 2009-1111035 A

  In this way, the lighting device is protected when the output voltage drops due to LED short-circuit failure or output terminal short-circuit, and when the output voltage rises due to LED disconnection failure or disconnection of the connector that connects the LED element and the lighting device. Both protection and protection circuits are required, which may complicate the circuit.

  In addition, a smoothing capacitor is connected to the output in order to smooth the current that flows through the LED in the lighting device that lights the LED, but in recent years, the size and output of LED lighting fixtures have increased, and the output capacitor has also increased its capacity. Tend to. For this reason, immediately after the lighting device starts driving due to power-on or the like, the capacitor is not sufficiently charged, and thus a state where the output voltage is low occurs for a predetermined period. In such a case, there is a possibility of erroneous determination even if the LED is normal.

  The present invention provides a light source lighting device that performs a protection operation when the output voltage drops and the output voltage rises reliably with a simple circuit configuration, and prevents the normal state where the output voltage of the capacitor is low from being erroneously determined as abnormal. The purpose is to provide.

The light source lighting device of the present invention is
DC power supply circuit section for starting operation and outputting DC voltage, supplying DC current to the light source by applying the DC voltage to the light source,
An output voltage detection unit for detecting an output voltage output from the DC power supply circuit unit;
Targeting a first threshold value and a second threshold value smaller than the first threshold value, the output voltage detected by the output voltage detection unit exceeds the first threshold value and less than the second threshold value When the output voltage exceeds the first threshold, the output voltage is determined to be abnormal when the output voltage exceeds the first threshold. And an abnormal voltage determination unit.

  According to the light source lighting device according to the present invention, the output voltage detection unit and the abnormal voltage determination unit are provided, and when the output voltage signal level detected by the output voltage detection unit exceeds the predetermined first threshold value, If the threshold value is less than 2, the abnormal voltage determination unit stops the operation of the light source lighting device as an output voltage abnormality. In addition, even if the output voltage signal level becomes less than the second threshold value for a predetermined period after the light source lighting device starts operating, it is not regarded as abnormal, and the operation of the light source lighting device is continued, thus preventing erroneous determination. The light source lighting device which can be comprised can be comprised.

FIG. 3 is a circuit block diagram of the light source lighting device 110 according to the first embodiment. FIG. 3 is a circuit block diagram of the light source lighting device 120 according to the first embodiment. FIG. 3 is an operation timing chart of the light source lighting device 120 according to the first embodiment. FIG. 4 is a circuit diagram of a light source lighting device 130 according to a second embodiment. FIG. 6 is an operation timing chart of the light source lighting device 130 according to the second embodiment. FIG. 6 is an operation timing chart of the light source lighting device 130 according to the second embodiment. FIG. 6 is a side sectional view of a lighting fixture 140 according to Embodiment 3.

Embodiment 1 FIG.
A basic configuration of the light source lighting device 110 of the first embodiment will be described with reference to FIG. In the first embodiment, description will be made using an LED (light emitting diode) as a light source. The light source lighting device 110 is a device that receives power from the commercial AC power supply 1 and lights the LED module 4. The AC / DC conversion unit 2 is a circuit that rectifies the commercial AC voltage input from the commercial AC power supply 1 and converts it into a DC voltage. The converted DC voltage is input to the DC / DC conversion unit 3. An LED module 4 composed of one or more LEDs 41 is connected to the output of the DC / DC conversion unit 3 (DC power supply circuit unit), a DC current is supplied from the DC / DC conversion unit 3, and each LED 41 of the LED module 4 is connected. Emits light. In the following description of the first to third embodiments, since the LED module 4 has a plurality of LEDs 41 connected in series, the current flowing through the LED 41 and the current flowing through the LED module 4 are the same. The current flowing through the LED module 4 is converted into a voltage signal (hereinafter, LED current detection signal) proportional to the current value by the LED current detection resistor 5 and input to the control circuit 6. The control circuit 6 compares the detected LED current detection signal with a signal indicating the target current value of the LED module 4 (target current signal), and DC / DC so that the current flowing through the LED module 4 becomes the target value. A so-called feedback control for controlling the conversion unit 3 is performed. Thereby, a stable predetermined direct current is supplied to the LED module 4.

  Further, an output voltage detection resistor 7 (output voltage detection unit) for detecting the output voltage of the DC / DC conversion unit 3 is connected to the output side of the DC / DC conversion unit 3. The output voltage detection resistor 7 includes voltage dividing resistors 7a and 7b. The output voltage detection resistor 7 divides the output voltage of the DC / DC conversion unit 3, steps down to an appropriate voltage, and the stepped down signal (hereinafter, output voltage detection signal) is a control circuit. 6 is input. Here, the output voltage of the DC / DC converter 3 is determined by the forward voltage of the connected LEDs and the series number, and the output voltage increases as the series number of the connected LEDs increases. A predetermined appropriate voltage range is set in advance in the control circuit 6, and the threshold value of the appropriate voltage range is referred to herein as a first threshold value and a second threshold value. The first threshold value and the second threshold value have a relationship of “first threshold value> second threshold value”. When the level of the output voltage detection signal exceeds the first threshold value, the control circuit 6 determines that the voltage is an overvoltage and the DC / DC conversion unit. The operation of 3 is stopped. Further, when the level of the output voltage detection signal becomes less than the second threshold, the control circuit 6 determines that the voltage is low and stops the operation of the DC / DC converter 3.

(In case of disconnection failure)
Consider a case where the output voltage of the DC / DC converter 3 is outside the proper voltage range. For example, assume that one LED is disconnected. When LEDs are connected in series, no current is supplied to all LEDs even if one LED is disconnected. For this reason, the output terminal of the DC / DC converter 3 is equivalently in a no-load state. The DC / DC converter 3 performs constant current control so that a constant current is always supplied to the LED module 4. For this reason, since the DC / DC conversion unit 3 operates to supply a predetermined target current value even in a no-load state, the output voltage operates in an increasing direction. Here, if the increased output voltage exceeds the maximum rating of the circuit component, the circuit component may possibly fail. Therefore, in order to suppress an increase in the output voltage, the control circuit 6 immediately stops the operation of the DC / DC converter 3 when the output voltage detection signal exceeds the first threshold value.

(In case of short circuit failure)
Next, it is assumed that some of the LEDs 41 are short-circuited. The output voltage of the DC / DC converter 3 is determined by the forward voltage of the connected LED and the series number. For this reason, when the voltage between the anode and the cathode of the LED having the short-circuit failure is zero, the output voltage decreases according to the number of the LEDs having the short-circuit failure. Further, when the output terminal of the DC / DC conversion unit 3 is short-circuited, the output voltage becomes almost zero. Usually, the DC / DC conversion unit 3 is designed in consideration of the number of connected LEDs in advance. Therefore, when the output voltage is significantly reduced due to a short circuit failure of the LED or a short circuit between the output terminals, the DC / DC conversion unit 3 operates outside the design operation range. As a result, for example, the feedback control of the LED current becomes unstable and flickering occurs in the LED, or the life of the light source lighting device is shortened and causes failure, which is not desirable. Therefore, when the output voltage detection signal becomes less than the second threshold value, the control circuit 6 immediately stops the operation of the DC / DC converter 3.

  FIG. 2 is a diagram illustrating the light source lighting device 110 of FIG. 1 as a light source lighting device 120 with a specific circuit configuration. Next, a more specific operation will be described using the light source lighting device 120 shown in FIG. The AC / DC conversion unit 2 of the light source lighting device 120 configures a capacitor input type rectifier circuit including the rectifier circuit 10 and the smoothing capacitor 11. The DC / DC conversion unit 3 constitutes a step-down chopper circuit including a switching element 12, a freewheeling diode 13, an inductor 14, and a smoothing capacitor 15. The control circuit 6 compares the drive control unit 17 that drives the switching element 12 with the LED current detection signal detected by the LED current detection resistor 5 (output current detection unit) and the target current signal, and drives and controls the comparison result. A current comparison unit 16 (light source current control unit) sent to the unit 17 and an abnormal voltage determination unit 18 that determines whether the signal level of the output voltage detection signal detected by the output voltage detection resistor 7 is within a predetermined range.

  The rectifier circuit 10 performs full-wave rectification on the AC voltage supplied from the commercial AC power supply 1. The smoothing capacitor 11 smoothes the voltage converted into a direct current by the rectifier circuit 10 and keeps the voltage constant. In the first embodiment, the AC / DC converter 2 constitutes a capacitor input type rectifier circuit including the rectifier circuit 10 and the smoothing capacitor 11. However, when power factor improvement is necessary, for example, the rectifier circuit and the boost chopper The power factor can be improved by using a power factor correction circuit composed of a circuit. In this case, the DC / DC converter 3 is connected to the subsequent stage of the power factor correction circuit.

  The DC / DC converter 3 constituting the step-down chopper circuit receives a direct current voltage from the AC / DC converter 2 and supplies a current to the LED module 4. First, when the switching element 12 is turned on, a current flows through a path of the smoothing capacitor 11 → the switching element 12 → the inductor 14 → the smoothing capacitor 15 → the smoothing capacitor 11 and charges the smoothing capacitor 15 while storing energy in the inductor 14. Next, when the switching element 12 is turned off, the energy stored in the inductor 14 is released, a current flows through the path of the inductor 14 → smoothing capacitor 15 → freewheeling diode 13 → inductor 14, and the energy of the inductor 14 charges the smoothing capacitor 15. Is done. The switching element 12 is repeatedly turned on and off at high speed, and the above operation is repeated. A current is supplied from the smoothing capacitor 15 to the LED module 4. At this time, the smoothing capacitor 15 serves to suppress and smooth the pulsation of the current supplied to the LED. The drive control unit 17 can adjust the current value supplied to the LED module 4 by adjusting the duty ratio of the switching element 12.

(Constant current feedback control)
When a current starts to flow through the LED module 4, the current flowing through the LED module 4 is detected by being converted into a voltage signal by the LED current detection resistor 5 and is input to the current comparison unit 16 of the control circuit 6. The current comparison unit 16 compares the input LED current detection signal with the target current signal (set value). For example, when the target current signal is larger than the LED current detection signal, the on-duty ratio of the switching element 12 is increased. A command is sent to the drive control unit 17. In response to this, the drive control unit 17 increases the on-duty ratio of the switching element 12 and increases the current flowing through the LED module 4. When the target current signal is smaller than the LED current detection signal, the current comparison unit 16 sends a command for reducing the on-duty ratio of the switching element 4 a to the drive control unit 17. In response to this, the drive control unit 17 decreases the on-duty ratio of the switching element 12 and decreases the current flowing through the LED module 4. As described above, the LED current detection signal and the target current signal are compared with each other by the cooperation of the current comparison unit 16 and the drive control unit 17, and the duty ratio of the switching element 12 is controlled in a direction in which the difference between the two becomes small. Perform feedback control.

(Abnormal voltage determination unit 18)
Next, operations of the output voltage detection resistor 7 and the abnormal voltage determination unit 18 will be described. As described above, when the LED is broken or short-circuited while the LED is lit, the output voltage of the DC / DC conversion unit 3 fluctuates. Therefore, the output voltage detection signal detected by the output voltage detection resistor 7 is used as the abnormal voltage determination unit 18. Monitor with. When the level of the output voltage detection signal is outside the “predetermined appropriate voltage range”, that is, when it exceeds the first threshold or less than the second threshold, the abnormal voltage determination unit 18 performs DC / DC It is determined that the output voltage of the conversion unit 3 is in an abnormal state, and a stop instruction signal is output to the drive control unit 17. When the drive control unit 17 receives the stop instruction signal, the drive control unit 17 takes measures to stop the operation of the light source lighting device 120 (DC / DC conversion unit 3) (switching stop of the switching element 12). Here, the first threshold is set to a value higher than the second threshold.

  By the way, the smoothing capacitor 15 connected to the output terminal of the DC / DC converter 3 may be a capacitor having a relatively large capacity in order to remove and smooth the ripple of the supply current to the LED. Therefore, immediately after the DC / DC converter 3 is started up, such as when the power is turned on, the smoothing capacitor 15 is not sufficiently charged, so the output voltage is low. Therefore, the output voltage of the DC / DC converter 3 may be less than the second threshold immediately after the start of the DC / DC converter 3 is started. For this reason, immediately after the commercial AC power supply 1 is turned on (immediately after the DC / DC conversion unit 3 is started), the abnormal voltage determination unit 18 determines that the output voltage detection signal is less than the second threshold value and controls the drive control unit 17. Therefore, there is a possibility that the operation of the DC / DC conversion unit 3 is stopped and the LED module 4 is not lit despite the normal state.

(Disabling the second threshold)
Therefore, in order to prevent such an erroneous determination, the abnormal voltage determination unit 18 makes the second threshold invalid and becomes less than the second threshold for a predetermined period immediately after starting the DC / DC conversion unit 3 such as when the commercial AC power is turned on. Even so, the operation of the DC / DC converter 3 is not stopped. That is, even in such a case, the abnormal voltage determination unit 18 does not output a stop instruction signal to the drive control unit 17. Then, after the predetermined period has elapsed, the output capacitor (smoothing capacitor 15) is sufficiently charged, and after the LED module 4 reaches a voltage that causes lighting, the abnormal voltage determination unit 18 validates the second threshold value. The predetermined period for invalidation is set in the abnormal voltage determination unit 18 in advance. Thus, immediately after the DC / DC converter 3 is activated, even if the smoothing capacitor 15 is not sufficiently charged, it is not determined whether the output voltage detection signal is less than the second threshold value. The non-lighting of the LED module 4 due to erroneous determination immediately after startup can be prevented.

(Description of operation)
FIG. 3 is a diagram showing a series of operations of the light source lighting device 120 after the DC / DC conversion unit 3 is activated. The operation will be described with reference to FIG. For example, assume that commercial AC power is turned on at the timing t1. Accordingly, it is assumed that the DC / DC conversion unit 3 is activated at the timing t2. As a result, the voltage of the smoothing capacitor 15 gradually increases. In the period (1) (t2 to t3) in the figure, the abnormal voltage determination unit 18 sets the second threshold value to be invalid and only the first threshold value to be valid. When the voltage of the smoothing capacitor 15 reaches a voltage at which the LED is turned on (point W in FIG. 3C), a current starts to flow through the LED, and the LED starts to turn on. When the LED starts lighting, output voltage detection based on the second threshold is enabled at the timing t3, and the output voltage is monitored (period (2) (t3 to t4) shown in FIG. 3A).

  Next, it is assumed that the LED is broken due to some cause. Then, the voltage of the output capacitor rises, and when the output voltage detection signal exceeds the first threshold at timing t4, the abnormal voltage determination unit 18 determines that the DC / DC conversion unit 3 is abnormal and drives the stop instruction signal. Output to the control unit 17. Immediately after receiving the stop instruction signal, the drive control unit 17 stops the DC / DC conversion unit 3 (switching of the switching element 12) to reduce the output voltage (period (3) in FIG. 3A). Similarly, when the output voltage decreases for some reason and becomes less than the second threshold value, the abnormal voltage determination unit 18 similarly outputs a stop instruction signal to the drive control unit 17 to stop the DC / DC conversion unit 3. Here, in the waveform of FIG. 3, the commercial AC power supply 1 represents LOW as a power failure state and HIGH as an energized state. The DC / DC converter 3 represents LOW as a stop state (OFF) and HIGH as an operation state (ON). The first threshold effective period and the second threshold effective period indicate that LOW is in an invalid state and HIGH is in an effective state.

  As described above, in the light source lighting devices 110 and 120 according to the first embodiment, the means for detecting the output voltage and the means for determining the abnormal voltage are provided, and when the output voltage detection signal exceeds the first threshold, or the second threshold If it is less than that, the output voltage is determined to be abnormal, and the operation of the light source lighting device is stopped. In addition, the second threshold value is invalidated for a predetermined period after the light source lighting device starts operation, and the operation of the light source lighting device is continued even when the light source lighting device is less than the second threshold value. It is possible to configure a light source lighting device that can prevent the light source lighting device from malfunctioning during an abnormal operation due to an output voltage drop and can reliably prevent erroneous determination.

  In the above first embodiment, the step-down chopper circuit is used as a circuit for supplying current to the LED. However, other circuit methods may be used as long as the circuit method can supply current to the LED, such as a flyback converter. But you can. The abnormal voltage determination unit 18 uses, for example, an A / D converter mounted on a microcomputer to capture the output voltage detection signal, set the first threshold value and the second threshold value by software, and compare the magnitude relationship with the output voltage detection signal. This can be easily realized. If the comparison result exceeds the first threshold value or is less than the second threshold value, a stop instruction signal for stopping the drive of the DC / DC conversion unit 3 may be given from the microcomputer to the drive control unit 17.

  Furthermore, although Embodiment 1 has been described using an LED as a light source, for example, an organic EL may be used instead of the LED. In this case, the organic LE can be connected to the output terminal of the DC / DC converter 3. With such a simple circuit configuration, it is possible to configure a light source lighting device that can prevent the light source lighting device from failing during an abnormal operation due to an increase in output voltage or a decrease in output voltage, and can reliably prevent erroneous determination.

Embodiment 2. FIG.
Next, the light source lighting device 130 of Embodiment 2 will be described with reference to FIG. In the second embodiment, description will be made using an LED as a light source. FIG. 4 is a circuit block diagram of the light source lighting device 130. The difference from FIG. 2 in the first embodiment is that two circuits of DC / DC converters composed of step-down chopper circuits are provided after the AC / DC converter 2 composed of capacitor input rectifier circuits, and the color temperature variable / dimming function. The dimming interface 19 is added. In the second embodiment, LED modules having different color temperatures are connected to the outputs of the two DC / DC converters 3a and 3b as light sources, and the currents are adjusted independently, whereby LEDs having two color temperatures are adjusted. The present invention relates to a light source lighting device that sets mixed color light generated from a module to an arbitrary color temperature and light quantity.

  In FIG. 4, components other than the commercial AC power source 1, the LED modules 4 a and 4 b, and the dimming controller 20 are components of the light source lighting device 130. The AC / DC converter 2 of the light source lighting device 130 constitutes a capacitor input type rectifier circuit including the rectifier circuit 10 and the smoothing capacitor 11. The first DC / DC converter 3a constitutes a step-down chopper circuit including a switching element 12a, a free wheeling diode 13a, an inductor 14a, and a smoothing capacitor 15a. The second DC / DC converter 3b has the same configuration as the first DC / DC converter 3a. The control circuit 6 includes a first drive control unit 17a that drives the switching element 12a, a second drive control unit 17b that drives the switching element 12b, and an LED current detection signal and a target current detected by the first LED current detection resistor 5a. The first current comparison unit 16a that compares the signal and sends the comparison result to the first drive control unit 17a, the LED current detection signal detected by the second LED current detection resistor 5b, and the target current signal, and the comparison result To determine whether the signal level of the output voltage detection signal detected by the second current comparison unit 16b and the first and second output voltage detection resistors 7A and 7B is within a predetermined range. A voltage determination unit 18 is provided.

  The AC / DC converter 2 rectifies the AC voltage supplied from the commercial AC power source 1 to obtain a smoothed DC voltage. In the second embodiment, the AC / DC converter 2 constitutes a capacitor input type rectifier circuit including the rectifier circuit 10 and the smoothing capacitor 11. However, when power factor improvement is required, for example, a rectifier circuit and a boost chopper circuit It is possible to improve the power factor by using a power factor improving circuit constituted by In this case, DC / DC conversion units 3a and 3b are connected to the subsequent stage of the power factor correction circuit.

  The first DC / DC converter 3 a and the second DC / DC converter 3 b share the AC / DC converter 2 and are connected in parallel to the smoothing capacitor 11. LED modules having different color temperatures are connected to each DC / DC converter. For example, in the second embodiment, the LED module 4a having a color temperature of 3000K is connected to the first DC / DC converter 3a, and the LED module 4b having a color temperature of 5000K is connected to the second DC / DC converter 3b. Thus, by mixing the light output from the LED module 4a having a color temperature of 3000K and the light output from the LED module 4b having a color temperature of 5000K, mixed color light having an intermediate color temperature can be obtained. Then, by changing the ratio of the direct current output from the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b, the mixed color light can be adjusted to an arbitrary color temperature and dimming rate.

  In the first DC / DC converter 3a, the switching element 12a is driven by the first drive controller 17a, and supplies current to the LED module 4a. The current of the LED module 4a is detected by the first LED current detection resistor 5a and converted into a voltage signal. The detected LED current detection signal is input to the first current comparison unit 16a. On the other hand, a target current signal (set value) determined by a dimming signal input from the dimming controller 20 is output from the dimming interface 19 and input to the first current comparison unit 16a. The first current comparison unit 16a compares the LED current detection signal with the target current signal, and outputs an instruction signal to the first drive control unit 17a so as to adjust the duty ratio of the switching element 12a in the direction in which both match.

  The second DC / DC conversion unit 3b is provided for the purpose of supplying a current to the LED module 4b having a color temperature of 5000K, and the control principle is the same as that of the first DC / DC conversion unit 3a described above, so the description thereof is omitted. . The operation principle of the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b made of the step-down chopper circuit is the same as that of the first embodiment, and thus the description thereof is omitted.

  The dimming controller 20 is provided outside the light source lighting device 130, and is a setting device for the user to set the lighting fixture (light source lighting device 130) to an arbitrary color temperature and dimming rate. The dimming controller 20 is, for example, a volume or a remote controller provided on a wall. By operating the dimming controller 20 such as a volume or a remote controller, a desired color temperature and dimming rate are set. The dimming controller 20 outputs a dimming signal that indicates the current values of the LED module 4a and the LED module 4b in order to turn on the luminaire with the set dimming rate and color temperature. The dimming signal output from the dimming controller 20 is input to the dimming interface 19 provided in the light source lighting device 130, and the dimming signal is decoded. The dimming interface 19 determines a current value to be passed through the LED module 4a and the LED module 4b specified by the dimming signal, and sends a target current signal (set value) to the first current comparing unit 16a and the second current comparing unit 16b. input.

  Next, the output voltage detection operation of the first DC / DC converter 3a and the second DC / DC converter 3b will be described. The abnormal voltage determination unit 18 monitors the output voltages of the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b via the first output voltage detection resistor 7A and the second output voltage detection resistor 7B. As in the first embodiment, when the signal level of the output voltage detection signal exceeds the first threshold value or less than the second threshold value, a stop instruction signal is output to stop the operation of the corresponding DC / DC converter. . Here, as in the first embodiment, the smoothing capacitor 15a and the smoothing capacitor 15b are insufficiently charged immediately after the start-up, so that the output voltage detection signal becomes less than the second threshold value, and the abnormal voltage determination unit 18 is erroneous. There is a possibility of judging. Therefore, the abnormal voltage determination unit 18 makes the second threshold value invalid for a predetermined period after the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b start to operate, and the output voltage detection signal is less than the second threshold value. However, the setting is made so as not to stop the operation of the DC / DC converter. Incidentally, regarding the first threshold value, the abnormal voltage determination unit 18 is set to be effective at the same time as the DC / DC conversion unit starts the operation. Thereby, for example, when the DC / DC converter starts to be activated in a no-load state, the operation can be stopped instantaneously.

  Next, when the output voltage detection signal is less than the second threshold value after the elapse of a predetermined period, the abnormal voltage determination unit 18 determines that the LED is a short circuit failure or a short circuit of the output terminal, and outputs DC / The operation of the DC converter is stopped. Here, when only one of the first and second DC / DC converters exceeds the first threshold value or falls below the second threshold value, that is, the other output voltage detection signal is within the normal range. In this case, the abnormal voltage determination unit 18 stops the operation of only the DC / DC conversion unit determined to be an abnormal voltage, and the DC / DC conversion unit whose output voltage is within the normal range continues to light the LED. That is, the abnormal voltage determination unit 18 outputs a stop instruction signal only to the drive control unit that drives the DC / DC conversion unit determined to be abnormal. Thereby, it can prevent that all LED light extinguishes.

  For example, when the LED module of 3000K and the LED module of 5000K are lit with mixed color light and the LED module of 3000K is short-circuited and becomes less than the second threshold value, the LED module of 3000K is turned on. The first DC / DC conversion unit 3a is stopped, but the second DC / DC conversion unit 3b to which the 5000K LED module is connected continues to operate. For this reason, lighting with 3000K and 5000K mixed color light is impossible, but if only a 5000K LED is lit, a minimum illuminance can be secured. This can reduce the risk that the entire lighting fixture will be unlit.

(Fade-in lighting function)
Here, when the light source lighting device 130 (control circuit 6) starts the lighting of the LED when the commercial AC power source 1 is turned on or a signal instructing lighting is input from the light control controller 20, In order to suppress it, it has a fade-in lighting function that gradually increases the LED current. This is because the LED is a point light source that has a small light emitting area compared to other light sources, for example, fluorescent lamps, and thus has the characteristic that glare is strongly felt even with the same luminous flux. Therefore, at the start of lighting, if the rise of light is steep, it is easy to feel dazzling and uncomfortable.

  During normal lighting, the LED modules 4a and 4b are lit at the current value set by the dimming controller 20, but at the start of lighting, the control circuit 6 (current comparison unit and drive control unit) is turned on by the fade-in lighting. Gradually increase the current to the current value to reduce glare at the start of lighting. When the LED current reaches the target current, the control circuit 6 thereafter performs a normal lighting operation, and the LED is lit at the target current value set by the dimming controller 20.

  However, when performing the fade-in lighting control in this way, the DC / DC conversion unit is controlled so that the rise of the LED current becomes gentle according to the comparison result of the current comparison unit, and therefore the first and second smoothing capacitors 15a, The charging current to 15b is also reduced. Accordingly, since the rise of the capacitor voltage is further moderated, the output voltage detection signal becomes less than the second threshold during the fade-in lighting, and the abnormal voltage determination unit 18 may make an erroneous determination.

  Therefore, in the second embodiment, in order to reliably prevent erroneous determination, as shown in FIG. 5, for the abnormal voltage determination unit 18, the second threshold value is invalidated during the fade-in lighting period, and a predetermined period from the end of the fade. After the elapse, the second threshold values of the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b are made valid. Here, since the target current value differs between the 3000K LED module and the 5000K LED module depending on the set value of the signal of the dimming controller 20, as shown in FIG. 5, the timing when the fade-in ends is the first DC / DC. The conversion unit 3a and the second DC / DC conversion unit 3b are different from each other. In FIG. 5, a dimming signal is input by the dimming controller 20 at the timing t1, and lighting is instructed. As a result, the first DC / DC converter 3a and the second DC / DC converter 3b start to operate, and the LED current (DC / DC converter output current in the figure) gradually increases due to fade-in lighting. Here, the second DC / DC conversion unit 3b reaches the target current first at the timing t2, and then is normally lit. Subsequently, the first DC / DC converter 3a reaches the target current at the timing of t3. Then, after the fade-in ends, the second threshold value is made valid for the abnormal voltage determination unit 18 at the timing t4 after a predetermined period.

  The timing at which the second threshold value of the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b becomes effective may be effective at the same time as shown in FIG. 5a, or as shown in FIG. In addition, the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b may count at the end of the fade-in lighting, respectively, and after the predetermined period has elapsed, the second threshold value may be enabled at different timings. That is, as shown in FIG. 6, the first DC / DC conversion unit 3a finishes the fade-in at the timing of t3, and the abnormal voltage determination unit 18 counts for a predetermined time from this time and makes the second threshold effective at the timing of t5. To do. The second DC / DC conversion unit 3b finishes the fade-in at the timing t2, and the abnormal voltage determination unit 18 counts for a predetermined time from this time and validates the second threshold at the timing t4. Although not shown, the abnormal voltage determination unit 18 may validate the second threshold value when the LED current reaches a predetermined current during fade-in lighting.

  Incidentally, it is desirable that the first threshold value for the purpose of overvoltage protection is made effective immediately after the DC / DC conversion unit is activated regardless of whether or not the fade-in lighting control is performed. As a result, when the power is turned on in the LED disconnection or no-load state during fade-in lighting, the overvoltage can be detected and stopped in the shortest time, so the time delay from the occurrence of the overvoltage until the operation is stopped Can be minimized.

(Fade out lights off)
Next, it is assumed that the dimming controller 20 outputs a turn-off instruction signal for instructing turn-off. Normally, the control circuit 6 may stop the operation of the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b immediately after receiving the turn-off instruction signal, and turn off the LED module 4a and the LED module 4b. However, for example, a so-called fade-out extinction may be performed in which the brightness is gradually reduced and extinguished in order to prevent a high-quality effect and the room from darkening instantaneously. In this case, since the LED current is gradually reduced, the voltage of the smoothing capacitor 15 gradually decreases. However, if the voltage of the smoothing capacitor 15 becomes less than the second threshold value during the process, There is a risk that the operation of the step-down converter stops and the LED goes off midway.

  Therefore, in the second embodiment, as shown in FIG. 5, the second threshold value is invalidated in the setting of the abnormal voltage determination unit 18 during the fade-out period. In FIG. 5, the second threshold value is disabled until the output current of the DC / DC converter becomes zero after the extinction signal is output from the dimming controller 20 at the timing t5. That is, regarding the determination of the abnormal voltage determination unit 18, the first DC / DC conversion unit 3a invalidates the second threshold value from the timing t5 to the timing t7, and the second DC / DC conversion unit 3b includes the period from t5 to t6. The second threshold is invalid until the timing. In order to shorten the invalid period of the second threshold as much as possible, the abnormal voltage determination unit 18 may be set to invalidate the second threshold when the current becomes less than a predetermined current value during fade-out. For example, in FIG. 6, the setting of the abnormal voltage determination unit 18 is a setting in which the second threshold value is invalidated after the output current of the first DC / DC conversion unit 3 a decreases to the timing t <b> 7.

  As described above, regarding the abnormality determination of the DC / DC conversion unit by the abnormal voltage determination unit 18, even when the output voltage of the DC / DC conversion unit becomes less than the second threshold during the fade-out lighting, the DC / DC conversion is invalidated. Prevent the part from stopping. Thereby, it is possible to prevent disappearance due to erroneous determination during fade-out. Incidentally, it is desirable to keep the first threshold value for overvoltage protection effective even during fade-out. As a result, it is possible to stop the DC / DC conversion unit by detecting an LED disconnection that occurs during fade-out or a no-load state due to connector disconnection, so that it is possible to prevent a failure of an electronic component due to the occurrence of an overvoltage.

  As described above, in the light source lighting device in which LEDs having different color temperatures are connected to the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b and the color temperature is variable and dimmable, the first DC / DC conversion unit Since the determination using the second threshold is invalidated for the abnormality determination by the abnormal voltage determination unit 18 for a predetermined period after the operation of the 3a and the second DC / DC conversion unit 3b is started, it is possible to prevent the LED from being turned off due to an erroneous determination. Further, only the DC / DC conversion unit determined to be abnormal voltage by the abnormal voltage determination unit 18 is stopped, and the DC / DC conversion unit whose output voltage is within the normal range continues to light the LED. Can be prevented from turning off.

  In addition, when performing fade-in lighting control in order to prevent glare at the time of LED lighting, the second threshold value is invalidated during the fade-in lighting period with respect to the setting of the abnormality determination in the abnormal voltage determination unit 18, and predetermined after the fade ends. After the elapse of the period, the second threshold value of the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b is validated. Therefore, erroneous determination can be reliably prevented. In addition, during the fade-out period, the second threshold is invalidated with respect to the setting of the abnormality determination in the abnormal voltage determination unit 18, so that the operation of the DC / DC conversion unit is not stopped during the fade-out lighting. Thereby, it is possible to prevent disappearance due to erroneous determination during fade-out.

  In the second embodiment, an example in which LED modules of 3000K and 5000K are connected to the first DC / DC conversion unit 3a and the second DC / DC conversion unit 3b, respectively, is described. But it ’s okay. In the second embodiment, two lighting circuits (DC / DC converters) are provided. However, any plurality of lighting circuits may be used. Moreover, you may include the LED module of the same color temperature. For example, in the case of three systems, two systems may be 3000K, and the remaining one system may be a color temperature of 5000K.

  Further, although the step-down chopper circuit has been described as a circuit for supplying current to the LED module, other circuit methods may be used as long as the circuit method can supply current to the LED module, for example, a flyback converter. Furthermore, in Embodiment 2, the LED module is used as the light source. However, for example, an organic EL may be used. In this case, by connecting organic ELs having different color temperatures to each step-down chopper circuit, color temperature variable control becomes possible, and when the output voltage is monitored and the voltage is outside the predetermined range, the circuit operation is immediately stopped. The effect similar to the case where an LED module is used as a light source can be acquired.

Embodiment 3 FIG.
FIG. 7 is a side cross-sectional view of the LED lighting apparatus 140 according to Embodiment 3. The light source lighting device 120 (or the light source lighting device 130) described in the first and second embodiments is housed in the lighting fixture body 30 and connected to a commercial AC power source via the power line 32 and the connector 33. The LED mounting substrate 35 on which the LED package 34 is mounted is mounted on the light emitting surface of the lighting fixture body 30 and connected to the light source lighting device 120 (or the light source lighting device 130) by the wiring 36 to form the LED lighting fixture 140. In the case of the light source lighting device 130 with variable color temperature according to the second embodiment, the LED packages 34 a and 34 b having different color temperatures are mounted on the LED mounting substrate 35. Although not shown, the light source lighting device 120 (or the light source lighting device 130) is provided with a dimming signal input terminal to which a dimming signal line from the dimming controller 20 is connected.

  According to the LED lighting apparatus 140 according to the third embodiment, the light source lighting device described in each embodiment can be incorporated, and the lighting apparatus incorporating these light source lighting apparatuses is reliable with a simple circuit configuration. In addition, it is possible to perform a protection operation when the output voltage is lowered and when the output voltage is raised. In addition, although LED is used as a light source in this Embodiment 3, it is good also as an organic EL lighting fixture using organic EL etc.

  DESCRIPTION OF SYMBOLS 1 Commercial AC power source, 2 AC / DC conversion part, 3a 1st DC / DC conversion part, 3b 2nd DC / DC conversion part, 4 LED module, 41 LED, 5 Current detection resistance, 6 Control circuit, 7 Output voltage detection resistance, 8 LED, 10 rectifier circuit, 11 smoothing capacitor, 12 switching element, 13 freewheeling diode, 14 inductor, 15 smoothing capacitor, 16 current comparison unit, 17a first drive control unit, 17b second drive control unit, 18 abnormal voltage determination unit , 19 Dimming interface, 20 Dimming controller, 30 Lighting fixture body, 31 Light source lighting device, 32 Power line, 33 Connector, 34 LED package, 35 LED mounting board, 36 Wiring, 110, 120, 130 Light source lighting device, 140 LED lighting fixtures.

Claims (8)

DC power supply circuit section for starting operation and outputting DC voltage, supplying DC current to the light source by applying the DC voltage to the light source,
An output voltage detection unit for detecting an output voltage output from the DC power supply circuit unit;
A first threshold value, the target and the smaller than the first threshold second threshold value, the output voltage detected by the output voltage detecting unit, when the second more than the first threshold value When the output voltage exceeds the first threshold for a predetermined period after the output of the DC power supply circuit unit is determined to be abnormal when the output voltage is determined to be abnormal in any case of being less than a threshold A light source lighting device comprising: an abnormal voltage determination unit that determines only the abnormality as an abnormality and invalidates the determination based on the second threshold value . The light source lighting device further includes:
An output current detection unit for detecting a signal corresponding to the output current of the DC power supply circuit unit as a detection signal;
The detection signal detected by the output current detection unit is compared with a set value set in advance as a value corresponding to a target current to be output by the DC power supply circuit unit, and the detection signal approaches the set value. By controlling the DC power supply circuit unit and controlling the DC power supply circuit unit until the detection signal reaches the set value after the DC power supply circuit unit starts to start. and a light source current control unit that executes a control fade-system shows gradually control for increasing the output current of the DC power supply circuit unit with the passage,
The abnormal voltage determination unit
For a predetermined period including at least a fade-in period in which the fade-in control by the light source current control unit is executed after the DC power supply circuit unit starts to start, the output voltage of the DC power circuit unit is 2. The light source lighting according to claim 1, wherein only when the first threshold value is exceeded is determined to be abnormal, and the determination based on the second threshold value is validated after the predetermined period including at least a fade-in period. apparatus. The light source lighting device further includes:
An output current detection unit for detecting a signal corresponding to the output current of the DC power supply circuit unit as a detection signal;
The detection signal detected by the output current detection unit is compared with a set value set in advance as a value corresponding to a target current to be output by the DC power supply circuit unit, and the detection signal approaches the set value. By controlling the DC power supply circuit unit and controlling the DC power supply circuit unit until the detection signal reaches the set value after the DC power supply circuit unit starts to start. and a light source current control unit that executes a control fade-system shows gradually control for increasing the output current of the DC power supply circuit unit with the passage,
The abnormal voltage determination unit
The determination based on the second threshold value is validated when the detection signal from the output current detection unit reaches a predetermined value during execution of the fade-in control by the light source current control unit. The light source lighting device according to 1. The light source lighting device is:
A plurality of the DC power supply circuit sections for supplying the DC current to the light sources connected to the light sources;
A plurality of the output voltage detection units that are provided for each of the DC power supply circuit units and detect output voltages output from the corresponding DC power supply circuit units;
A plurality of output current detection units that are provided for each of the DC power supply circuit units and detect signals corresponding to output currents of the corresponding DC power supply circuit units as detection signals;
The detection signal detected by each of the output current detection units, and a set value set in advance as a value corresponding to a target current to be output by the DC power supply circuit unit corresponding to each of the output current detection units In comparison, each DC power supply circuit unit is controlled so that the detection signal approaches the set value, and the detection signal reaches the set value after each DC power supply circuit unit starts to start. until, by controlling each of the direct-current power supply circuit unit, the light source current control unit that executes a control fade-system showing the control to gradually increase the respective said output current of said DC power supply circuit section with time And
The plurality of DC power supply circuit units are
Starts almost at the same time,
The abnormal voltage determination unit
A predetermined period including at least a fade-in period during which the fade-in control is performed by the light source current control unit after each DC power supply circuit unit starts to start is the output voltage of the DC power circuit unit. Is determined to be abnormal only when the value exceeds the first threshold, and after the predetermined period including at least a fade-in period, the determination based on the second threshold is valid, and the determination based on the second threshold is performed. 2. The light source lighting device according to claim 1, wherein the valid end point of the predetermined period is set to a different timing or substantially the same timing for each of the DC power supply circuit units. The light source lighting device further includes:
An output current detection unit for detecting a signal corresponding to the output current of the DC power supply circuit unit as a detection signal;
The detection signal detected by the output current detection unit is compared with a set value set in advance as a value corresponding to a target current to be output by the DC power supply circuit unit, and the detection signal approaches the set value. In this way, the DC power supply circuit unit is controlled so that the detection signal at a substantially set value is turned off, and the DC power supply circuit unit is controlled as time passes by controlling the DC power supply circuit unit. and a gradual light source current control unit that executes the fade-out control indicates a control to reduce the said output current,
The abnormal voltage determination unit
When the turn-off signal is input, or when the detection signal from the output current detection unit reaches a predetermined value during execution of the fade-out control by the light source current control unit, the second The light source lighting device according to claim 1, wherein the determination based on the threshold value is invalidated. The light source lighting device is:
Light source lighting device according to any one of claims 1 to 5, characterized in that as said light source, using LED. The light source lighting device is:
Light source lighting device according to any one of claims 1 to 5, characterized in that as said light source, using EL. Lighting device with a light source lighting device according to any one of claims 1-7.

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