JP5986124B2 - Lighting device and lighting device - Google Patents

Description

  The present invention relates to a lighting device and a lighting device. The present invention particularly relates to a light emitting diode lighting device.

  In recent years, light-emitting diode illumination has attracted attention from the viewpoint of energy saving. Unlike conventional fluorescent lamps, light emitting diodes can be designed with various types of outputs depending on the number of connected light emitting diode elements. As a connection method of light emitting diode elements, serial connection is currently the mainstream, and when one light emitting diode element has an open failure, all the light emitting diode elements connected in series are turned off. In order to avoid this problem, a bypass circuit is configured in parallel with the light emitting diode elements connected in series, and when the light emitting diode element has an open failure, both ends of the failed light emitting diode element are short-circuited by the bypass circuit. Thus, there is a technique for continuing lighting without turning off other light emitting diode elements (see, for example, Patent Document 1).

JP 2008-131007 A JP 2009-284721 A JP 2008-251276 A JP 2009-146713 A JP 2009-38247 A

  Unlike conventional fluorescent lamps, there are various types of light-emitting diode illumination without the output (the number of combinations of light-emitting diode elements) being defined by standards such as JIS. However, designing a light-emitting diode lighting device in accordance with the output of each light-emitting diode requires a lot of time and investment, and is practically impossible.

  For example, Patent Document 1 discloses a technique for continuing lighting even when one of the light emitting diode elements connected in series has an open failure. However, the combination of the lighting device and the number of light emitting diode elements other than the number allowed by the lighting device is not considered. Therefore, when more light-emitting diode elements than the allowable number are connected to the lighting device, there is a problem that an excessive load is applied to the electronic components constituting the circuit of the lighting device and the lighting device may break down. It was.

  An object of the present invention is to protect a circuit of a lighting device when a light emitting element is abnormal, for example, when an unacceptable number of light emitting elements are connected to the lighting device.

A lighting device according to one aspect of the present invention includes:
A lighting circuit for lighting the light emitting element by applying a voltage to the light emitting elements connected in series;
A measurement circuit for measuring the amount of voltage drop due to the light emitting element;
It is determined whether the amount of voltage drop measured by the measurement circuit is below a preset lower limit reference value. If it is determined that the voltage drop is below the lower limit reference value, the lighting circuit is controlled to A determination circuit for turning off or dimming the element,
n 2 is an integer of 1 or more,
The lighting circuit normally illuminates at least n 2 light emitting elements having a predetermined amount of voltage drop during lighting,
The determination circuit uses a value lower than a value obtained by multiplying the predetermined amount by n 2 as the lower limit reference value.

  According to one aspect of the present invention, the lighting device controls the lighting circuit to turn off the light emitting element when the amount of voltage drop due to the light emitting elements connected in series is below the preset lower limit reference value. Alternatively, since the light is dimmed, the circuit of the lighting device can be protected when the light emitting element is abnormal, such as when an unacceptable number of light emitting elements are connected to the lighting device.

1 is a circuit diagram of a lighting device according to Embodiment 1. FIG. It is the figure which showed the number of the light emitting diode elements which can be connected to the light emitting diode lighting device which concerns on Embodiment 1, and an upper limit reference value and a lower limit reference value. FIG. 6 is a circuit diagram of a lighting apparatus according to Embodiment 2. FIG. 6 is a circuit diagram of a lighting device according to Embodiment 3. FIG. 6 is a circuit diagram of a lighting device according to Embodiment 4. FIG. 10 is a diagram illustrating a relationship between a detection time constant of the voltage detection circuit according to the fifth embodiment and a time constant from when the light emitting diode element is open to failure until the thyristor is turned on. It is the figure which showed the number of the light emitting diode elements which need alerting | reporting in the light emitting diode lighting device which concerns on Embodiment 6, and the number of the light emitting diode elements which do not require alerting | reporting, an upper limit reference value, a lower limit reference value, and an alerting | reporting reference value. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram of lighting apparatus 100 according to the present embodiment.

  In FIG. 1, the lighting device 100 includes a light emitting diode lighting device 10 (an example of a lighting device) and an LED mounting board 90. The lighting device 100 includes a fixture (not shown) that fixes the light-emitting diode lighting device 10. The light emitting diode lighting device 10 includes a power supply rectifier circuit 11, an active filter circuit 12, an inverter circuit 13, a load circuit 14, an inverter control circuit 15, a determination circuit 20, and a voltage detection circuit 21 (an example of a measurement circuit). The LED mounting substrate 90 is obtained by mounting a plurality of light emitting diode elements 91 </ b> A to 91 </ b> D (examples of light emitting elements) whose lighting states are controlled by the light emitting diode lighting device 10 in series. In FIG. 1, four light emitting diode elements 91 </ b> A to 91 </ b> D are mounted on the LED mounting board 90, but other numbers of light emitting diode elements can be mounted on the LED mounting board 90. Here, it is assumed that the light-emitting diode elements 91A to 91D are all the same type of light-emitting diode elements (light-emitting diode elements having the same voltage drop amount), but different types of light-emitting diode elements (voltage drop amounts of which are the same). It may be a different light emitting diode element).

  The power supply rectifier circuit 11 includes a noise filter (not shown) and a diode bridge, and rectifies the power supply voltage and removes noise. The active filter circuit 12 boosts the power supply voltage rectified by the power supply rectifier circuit 11 to a predetermined DC voltage by switching along the power supply voltage waveform, and shapes the input current waveform to power factor and harmonics. To improve.

  The inverter circuit 13, the load circuit 14, and the inverter control circuit 15 constitute a lighting circuit 30 that applies a voltage to the light emitting diode elements 91A to 91D connected in series to light the light emitting diode elements 91A to 91D. The inverter circuit 13 alternately switches the switching elements Q1 and Q2 (for example, FETs) with a reverse polarity voltage output from the inverter control circuit 15, thereby converting the DC voltage boosted by the active filter circuit 12 into a high-frequency AC voltage. Convert to The load circuit 14 includes an inductor L1, capacitors C1 and C2, and a rectifier circuit 16. Capacitor C1 is a coupling capacitor. The rectifier circuit 16 includes diodes D1 to D4 and a capacitor C3, and directs current to the light emitting diode elements 91A to 91D connected in series to light the light emitting diode elements 91A to 91D. The capacitor C3 is a smoothing capacitor for removing a ripple of current flowing through the light emitting diode elements 91A to 91D. The load circuit 14 changes the resonance of the inductor L1 and the capacitor C2 at the operating frequency of the inverter circuit 13, thereby adjusting the current flowing through the light emitting diode elements 91A to 91D and dimming the light emitting diode elements 91A to 91D. The inverter control circuit 15 controls the operating frequency of the inverter circuit 13.

  The voltage detection circuit 21 includes resistors R1 and R2 and a capacitor C4. The voltage detection circuit 21 detects the sum of the voltage drops of all the light emitting diode elements 91A to 91D connected in series, and supplies a voltage indicating the detection value to the determination circuit 20. input. That is, the voltage detection circuit 21 measures the amount of voltage drop due to the light emitting diode elements 91 </ b> A to 91 </ b> D and transmits the measured amount of voltage drop to the determination circuit 20.

  The determination circuit 20 compares the voltage input from the voltage detection circuit 21 with a predetermined upper limit reference value V1 and a lower limit reference value V2. When the voltage is not less than the upper limit reference value V1 or not more than the lower limit reference value V2, the determination circuit 20 stops the inverter circuit 13 and turns off the light emitting diode elements 91A to 91D. Alternatively, the determination circuit 20 increases the operating frequency of the inverter circuit 13 by the inverter control circuit 15 to reduce the current flowing through the light emitting diode elements 91A to 91D. A resonance circuit is used as the load circuit 14, and when the operating frequency of the inverter circuit 13 is increased, the resonance of the load circuit 14 is weakened, and the outputs of the light emitting diode elements 91A to 91D are decreased. That is, the light emitting diode elements 91A to 91D are dimmed. Thus, the determination circuit 20 determines whether or not the amount of voltage drop measured by the voltage detection circuit 21 (here, the voltage input from the voltage detection circuit 21) exceeds the preset upper reference value V1. If it is determined that the upper limit reference value V1 is exceeded, the lighting circuit 30 is controlled to turn off or dimm the light emitting diode elements 91A to 91D. In addition, the determination circuit 20 determines whether or not the amount of voltage drop measured by the voltage detection circuit 21 (here, the voltage input from the voltage detection circuit 21) is below a preset lower reference value V2. When it is determined that the value is below the lower limit reference value V2, the lighting circuit 30 is controlled so that the light emitting diode elements 91A to 91D are turned off or dimmed.

  Here, the output (brightness) of the light emitting diode elements 91A to 91D is proportional to the current when the same light emitting diode element is used. Therefore, in order to make the brightness constant regardless of the number of light emitting diode elements connected in series, the lighting circuit 30 may be a constant current circuit. In the circuit system shown in FIG. 1, the operating frequency of the inverter circuit 13 may be made constant regardless of the number of light emitting diode elements connected in series. Even in a circuit system other than the circuit system shown in FIG. 1, for example, a down converter system, the current may be made constant regardless of the number of light-emitting diode elements connected in series.

  When any of the light emitting diode elements 91A to 91D has an open failure in the lighting device 100, resonance by the inductor L1 and the capacitor C2 becomes strong. For this reason, the voltage at both ends of the LED mounting substrate 90 becomes very large, and the circuit may break down. Therefore, when the voltage input from the voltage detection circuit 21 to the determination circuit 20 exceeds the upper limit reference value V1, the inverter circuit 13 is stopped or the operating frequency of the inverter circuit 13 is increased. Necessary. The same applies when the LED mounting substrate 90 is removed.

  In addition, when all of the light emitting diode elements 91A to 91D are short-circuited, there is a possibility that overcurrent continues to flow through the circuit and a heat generation failure occurs. Therefore, even when the voltage input from the voltage detection circuit 21 to the determination circuit 20 falls below the lower limit reference value V2, the inverter circuit 13 may be stopped or the operating frequency of the inverter circuit 13 may be increased. Necessary.

  A circuit system other than the circuit system shown in FIG. 1, for example, a down converter system, requires a protection circuit (protection mechanism) similar to the above.

  FIG. 2 is a diagram illustrating the number of light-emitting diode elements that can be connected (lighted) to the light-emitting diode lighting device 10, and the upper-limit reference value V1 and the lower-limit reference value V2.

  In FIG. 2, the vertical axis of the graph indicates the detection voltage Va of the voltage detection circuit 21, and the horizontal axis indicates the number of light emitting diode elements connected in series by the LED mounting substrate 90. For example, it is assumed that the voltage drop per element of the light emitting diode elements 91A to 91D shown in FIG. 1 is 3V, and the light emitting diode lighting device 10 can be connected from 1 element to 4 elements. In this case, the total voltage drop due to the light emitting diode elements changes from 3V × 1 = 3V to 3V × 4 = 12V. Here, if the voltage detection circuit 21 detects the sum of the voltage drops due to the light emitting diode elements to ½, the detection voltage Va becomes ½ of the sum of the voltage drops due to the light emitting diode elements. Therefore, n1 = 4 and n2 = 1 in FIG. 2, and the upper limit reference value V1 may be set to 6V and the lower limit reference value V2 may be set to 1.5V. That is, when the maximum value (maximum number of series connections) of light emitting diode elements that can be lit by the light emitting diode lighting device 10 is n1, and the minimum value (minimum series connection number) is n2, the upper limit reference value V1 is the light emitting diode element. The voltage drop per element × n1 and the lower limit reference value V2 may be set to the voltage drop per light emitting diode element × n2.

  As described above, the lighting circuit 30 has a maximum of n1 (n1 is an integer greater than or equal to 2, for example, n1 = 4) for a light emitting diode element whose voltage drop during lighting is a predetermined amount (for example, 3V). Assuming that the light is to be individually lit, the determination circuit 20 has a value obtained by multiplying the predetermined amount by n1 (for example, if the voltage detection circuit 21 detects the sum of the voltage drops due to the light emitting diode elements to ½). Further, the above value may be used as the upper limit reference value V1. Further, the lighting circuit 30 lights at least n2 (n2 is an integer of 1 or more, for example, n2 = 1) light emitting diode elements whose voltage drop during lighting is a predetermined amount (for example, 3V). If it is assumed, the determination circuit 20 has a value obtained by multiplying the predetermined amount by n2 (for example, if the voltage detection circuit 21 detects the sum of the voltage drops due to the light emitting diode elements to ½, The following value may be used as the lower limit reference value V2.

  As described above, according to the present embodiment, the light-emitting diode element can be turned on within a specified output range (number of connected light-emitting diode elements), and protection is provided to protect the circuit when the light-emitting diode element is abnormal. A light-emitting diode lighting device 10 including a circuit can be provided.

Embodiment 2. FIG.
In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 3 is a circuit diagram of lighting apparatus 100 according to the present embodiment.

  In FIG. 3, the lighting device 100 includes a light emitting diode lighting device 10 and an LED mounting substrate 90. The light emitting diode lighting device 10 is the same as in the first embodiment.

  In the LED mounting substrate 90, a bypass circuit including thyristors 92A to 92D (examples of switch elements), resistors R3A to R3D, and R4A to R4D in parallel with the light emitting diode elements 91A to 91D similar to those shown in FIG. Is connected. When any of the light emitting diode elements 91A to 91D has an open failure, the thyristors 92A to 92D conduct a bypass circuit that bypasses the light emitting diode element that has failed. For example, in a bypass circuit connected in parallel with the light emitting diode element 91A, when the light emitting diode element 91A has an open failure, the open voltage divided by the resistors R3A and R4A is applied to the gate of the thyristor 92A. For this reason, the thyristor 92A is turned on to bypass the light-emitting diode element 91A that has failed to open, so that the other light-emitting diode elements 91B to 91D can continue to light normally (without being dimmed). Here, it goes without saying that the divided voltage values of the resistors R3A and R4A are set to such values that the thyristor 92A is not turned on when the voltage drop occurs when the light emitting diode element 91A is normally lit. The bypass circuit connected in parallel with the light emitting diode elements 91B to 91D also operates in the same manner as described above when the light emitting diode elements 91B to 91D have an open failure, and the light emitting diode elements that are not open to failure normally light up. Makes it possible to continue.

  In the first embodiment, the light emitting diode lighting device 10 can light up the light emitting diode elements from the minimum series connection number n2 to the maximum series connection number n1, but one of the series connected light emitting diode elements is open failure. In such a case, it was necessary to operate the protection circuit. On the other hand, in the present embodiment, the light-emitting diode lighting device 10 does not operate the protection circuit because the bypass circuit operates even if any of the light-emitting diode elements connected in series fails. Thus, the light emitting diode element can be kept lit normally. Further, in the present embodiment, when all of the light emitting diode elements connected in series have an open failure, the detection voltage Va of the voltage detection circuit 21 falls below the lower limit reference value V2, and thus the light emitting diode lighting device 10 has a protection circuit. Will work.

  In the present embodiment, when all of the light emitting diode elements have an open failure, the detection voltage Va of the voltage detection circuit 21 is the sum of the voltage drops caused by the thyristors. Therefore, if the lower limit reference value V2 is set not lower than the voltage drop per light emitting diode element × n2, but the lower limit reference value V2 is the sum of the voltage drops caused by the thyristors (for example, the voltage per thyristor). Set lower than descent × n1). Thereby, when all of the light emitting diode elements have an open failure, the protection circuit can be reliably operated.

  When the LED mounting substrate 90 is removed, the light-emitting diode lighting device 10 operates the protection circuit because the detection voltage Va of the voltage detection circuit 21 exceeds the upper reference value V1 as in the first embodiment.

  Here, in general light emitting diode lighting fixtures, the light emitting diode lighting device and the LED mounting substrate are often connected by two electric wires. In the present embodiment, the bypass circuit is connected in parallel to the light emitting diode element. However, if the bypass circuit is to be mounted in the light emitting diode lighting device 10, the wiring becomes complicated, and the LED mounting from the light emitting diode lighting device 10 to the LED mounting. The number of wires up to the substrate 90 increases. Therefore, it is desirable to mount the bypass circuit on the LED mounting board 90 as shown in FIG.

  In addition, since the light emitting diode element generates a large amount of heat, an aluminum substrate or the like is often used as the LED mounting substrate in a general light emitting diode lighting fixture as a heat dissipation structure. Since the thyristor used in the bypass circuit is a component that generates heat due to a voltage drop, if it is disposed on an aluminum substrate on which a light-emitting diode element is mounted, heat dissipation can be improved. Furthermore, since it is not necessary to use electric wires from the light emitting diode lighting device 10 to the LED mounting substrate 90, the number of wirings can be reduced.

  In the present embodiment, thyristors 92A to 92D are used as switch elements used in the bypass circuit, but other semiconductor switches such as FETs and transistors can also be used. Also, a mechanical contact such as a relay can be used.

  As described above, according to the present embodiment, the same effect as in the first embodiment can be obtained, and light emission that can continue normal lighting of the light-emitting diode element even when the series-connected light-emitting diode elements have an open failure The diode lighting device 10 can be provided.

Embodiment 3 FIG.
The difference between the present embodiment and the second embodiment will be mainly described.

  FIG. 4 is a circuit diagram of lighting apparatus 100 according to the present embodiment.

  In the second embodiment, the switch elements are connected in parallel to each of the light emitting diode elements connected in series. However, in this embodiment, as shown in FIG. 4, the switch elements are provided for each predetermined number of light emitting diode elements. Connected in parallel.

  In the LED mounting substrate 90, a bypass circuit including a thyristor 92A (an example of a switch element) and resistors R3A and R4A is connected in parallel with the light emitting diode elements 91A and 91B connected in series. The thyristor 92A conducts a bypass circuit that bypasses the light emitting diode elements 91A and 91B when one of the light emitting diode elements 91A and 91B fails to open. As a result, the other light emitting diode elements 91C and 91D can be kept lit normally (without dimming). A bypass circuit composed of a thyristor 92B (an example of a switch element) and resistors R3B and R4B connected in parallel to the light emitting diode elements 91C and 91D is also affected by an open failure of any of the light emitting diode elements 91C and 91D. By operating in the same manner, the light emitting diode elements 91A and 91B can be kept lit normally.

Embodiment 4 FIG.
The difference between the present embodiment and the second embodiment will be mainly described.

  FIG. 5 is a circuit diagram of lighting apparatus 100 according to the present embodiment.

  In the second embodiment, the switch elements are connected in parallel to each of the light emitting diode elements connected in series. However, in the present embodiment, as shown in FIG. 5, the switch elements are connected to each LED mounting substrate. Yes.

  In the LED mounting board 90A, a bypass circuit including a thyristor 92A (an example of a switch element) and resistors R3A and R4A is connected in parallel with the light emitting diode elements 91A to 91D connected in series. The thyristor 92A conducts a bypass circuit that bypasses the light emitting diode elements 91A to 91D when any of the light emitting diode elements 91A to 91D fails to open. Accordingly, the light emitting diode elements 91E to 91L mounted on the other LED mounting boards 90B and 90C can be normally lit (without being dimmed). A bypass circuit composed of thyristors 92B (example of switch elements) and resistors R3B and R4B connected in parallel with the light emitting diode elements 91E to 91H on the LED mounting substrate 90B is also one of the light emitting diode elements 91E to 91H. When an open failure occurs, the light emitting diode elements 91A to 91D and 91I to 91L can continue to light normally by operating in the same manner as described above. The same applies to the bypass circuit connected in parallel with the light emitting diode elements 91I to 91L on the LED mounting substrate 90C.

Embodiment 5 FIG.
The difference between the present embodiment and the second embodiment will be mainly described.

  The configuration of lighting apparatus 100 according to the present embodiment is the same as that of the second embodiment shown in FIG. It may be the same as that of the third embodiment shown in FIG. 4 or the fourth embodiment shown in FIG.

  In the present embodiment, the voltage detection circuit 21 transmits the measured voltage drop amount to the determination circuit 20 after at least the time during which the thyristors 92A to 92D conduct the bypass circuit has elapsed. That is, the voltage detection circuit 21 causes a delay corresponding to the time. Therefore, when the light emitting diode element has an open failure, the time until the thyristor becomes conductive is shorter than the time it takes for the detection voltage Va of the voltage detection circuit 21 to exceed the upper limit reference value V1 after the light emitting diode element has an open failure. . Thus, in the present embodiment, at least the thyristors 92A to 92D have a timing at which the light emitting diode lighting device 10 starts the operation in which the determination circuit 20 controls the lighting circuit 30 to turn off or dimm the light emitting diode elements. Delay the time for which the bypass circuit is turned on. As described above, instead of causing the voltage detection circuit 21 to cause a delay, the determination circuit 20 may cause a delay (may be masked).

  FIG. 6 is a diagram showing the relationship between the detection time constant of the voltage detection circuit 21 and the time constant until the thyristor is turned on after an open failure of the light emitting diode element.

  In FIG. 6, the vertical axis of the graph indicates the detection voltage Va of the voltage detection circuit 21, and the horizontal axis indicates time. Until time t1, the voltage detection circuit 21 detects the total voltage drop caused by the light emitting diode elements 91A to 91D shown in FIG. For example, it is assumed that an open failure occurs while the light emitting diode element 91A is lit at time t1. As a result, an open circuit voltage is generated, and at the same time, the detection voltage Va of the voltage detection circuit 21 starts to rise. At this time, the thyristor 92A is not conductive yet, but the detection voltage Va of the voltage detection circuit 21 does not immediately exceed the upper limit reference value V1, but gradually depends on the time constant of the resistor R1 and the capacitor C4 of the voltage detection circuit 21. To rise. At time t2, the open circuit voltage is applied to the gate of the thyristor 92A by the resistors R3A and R4A, so that the thyristor 92A becomes conductive. Thereby, the detection voltage Va of the voltage detection circuit 21 starts to fall. After that, the voltage detection circuit 21 detects the sum of the voltage drops caused by the light emitting diode elements 91B to 91D that are not open-failed (in practice, including the voltage drop caused by the thyristor 92A). The time from the time t1 to the time t2 is determined by the resistance R3A and the gate capacitance of the thyristor 92A, but may be adjusted by a capacitor (not shown) connected in parallel to the resistance R4A.

  When there is no bypass circuit as in the first embodiment, the detection voltage Va of the voltage detection circuit 21 exceeds the upper limit reference value V1 at time t3, so that the protection circuit operates. On the other hand, in the present embodiment, under the condition of t3> t2, the thyristor 92A becomes conductive at time t2, so that the open circuit voltage disappears and the detection voltage Va of the voltage detection circuit 21 does not exceed the upper limit reference value V1. descend. Therefore, the light emitting diode elements 91B to 91D continue to light normally. On the other hand, also in the present embodiment, under the condition of t3 <t2, the protection circuit operates before the bypass circuit operates, and thus the light emitting diode elements 91B to 91D are dimmed or turned off. Therefore, by designing the voltage detection circuit 21, the determination circuit 20, and the like so that t3> t2, even when the light emitting diode element has an open failure during lighting, only the failed light emitting diode element is turned off. It becomes possible to continue lighting of other light emitting diode elements.

  The same operation as described above is performed not only when the light emitting diode element 91A fails during lighting at time t1, but also when another light emitting diode element 91B to 91D fails during lighting at time t1. Further, when the light emitting diode elements 91 </ b> A to 91 </ b> D including the light emitting diode elements that have already failed at the time t <b> 1 are turned on, the same operation as described above is performed.

Embodiment 6 FIG.
The difference between the present embodiment and the second embodiment will be mainly described.

  The configuration of lighting apparatus 100 according to the present embodiment is the same as that of the second embodiment shown in FIG. It may be the same as that of the third embodiment shown in FIG. 4 or the fourth embodiment shown in FIG.

  In the present embodiment, the notification reference value V3 is set between the upper limit reference value V1 and the lower limit reference value V2. The determination circuit 20 determines whether or not the amount of voltage drop measured by the voltage detection circuit 21 is equal to or less than a preset notification reference value V3. . As a notification method, various means such as making a sound, turning off the light emitting diode elements 91A to 91D, and blinking (flashing) the light emitting diode elements 91A to 91D can be used. In consideration of convenience during actual use, it is desirable that the light emitting diode elements 91A to 91D blink several times when the power is turned on. In this case, when the power is supplied, the determination circuit 20 controls the lighting circuit 30 to notify the light emitting diode elements 91A to 91D by blinking. Then, after blinking the light emitting diode elements 91A to 91D a predetermined number of times, the determination circuit 20 continues lighting the light emitting diode elements 91A to 91D that have not failed.

  FIG. 7 is a diagram showing the number of light emitting diode elements that need to be notified and the number of light emitting diode elements that do not need to be notified, and the upper limit reference value V1, the lower limit reference value V2, and the notification reference value V3. It is.

  In FIG. 7, the vertical axis of the graph indicates the detection voltage Va of the voltage detection circuit 21, and the horizontal axis indicates the number of light emitting diode elements connected in series by the LED mounting substrate 90. For example, when one or a plurality of light emitting diode elements among the light emitting diode elements 91A to 91D shown in FIG. 3 has an open failure and the bypass circuit operates, the voltage drop of the thyristor is less than the voltage drop of the light emitting diode element. Therefore, the determination circuit 20 can determine from the detection voltage Va of the voltage detection circuit 21 that the bypass circuit has been operated. The notification reference value V3 is set to notify when the determination circuit 20 detects a failure of a specified number of light emitting diode elements (number of mounted light emitting diode elements−n3). By notifying, it is possible to prompt the user of the lighting device 100 to replace the light emitting diode element.

  As described above, according to the present embodiment, the light-emitting diode lighting device 10 that has the same effects as those of the second embodiment and can notify when a specified number of light-emitting diode elements have failed is provided. Can be provided.

  As mentioned above, although embodiment of this invention was described, you may implement combining 2 or more embodiment among these. Alternatively, one of these embodiments may be partially implemented. Or you may implement combining two or more embodiment among these partially.

  DESCRIPTION OF SYMBOLS 10 Light emitting diode lighting device, 11 Power supply rectifier circuit, 12 Active filter circuit, 13 Inverter circuit, 14 Load circuit, 15 Inverter control circuit, 16 Rectifier circuit, 20 Determination circuit, 21 Voltage detection circuit, 30 Lighting circuit, 90, 90A- 90C LED mounting board, 91A to 91L light emitting diode element, 92A to 92D thyristor, 100 lighting device, C1 to C4 capacitor, D1 to D4 diode, L1 inductor, Q1, Q2 switching element, R1, R2, R3A to D, R4A to R4D resistance.

Claims (3)

A lighting circuit for lighting the light emitting element by applying a voltage to the light emitting elements connected in series;
A measurement circuit for measuring the amount of voltage drop due to the light emitting element;
It is determined whether the amount of voltage drop measured by the measurement circuit is below a preset lower limit reference value. If it is determined that the voltage drop is below the lower limit reference value, the lighting circuit is controlled to A determination circuit for turning off or dimming the element,
n 2 is an integer of 1 or more,
The lighting circuit normally illuminates at least n 2 light emitting elements having a predetermined amount of voltage drop during lighting,
The determination circuit uses a value lower than a value obtained by multiplying the predetermined amount by n 2 as the lower limit reference value. When the lighting circuit is connected to a light emitting element group composed of light emitting elements that are not malfunctioning and the amount of voltage drop during lighting is the predetermined amount, the light emission constituting the light emitting element group when the number of elements is two or more n, the lighting device according to claim 1, characterized in that for lighting the light-emitting element group. The lighting device according to claim 1 or 2 ,
A lighting device comprising: a plurality of light-emitting elements connected in series and whose lighting state is controlled by the lighting device.

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