JP2024063660A - Lighting devices and illumination devices - Google Patents

Abstract

[Problem] Reverse connection of a light source is detected by passing a current through a light-emitting element. [Solution] A lighting device 10 includes a lighting circuit 1 and a control circuit 2. The lighting circuit 1 supplies a DC current (output current I1) to a light source 3 having one or more light-emitting elements. The control circuit 2 controls the lighting circuit 1. The control circuit 2 has a detection mode in which a detection current smaller than the rated current of the lighting circuit 1 is supplied from the lighting circuit 1 to the light source 3 during a detection period to detect reverse connection of the light source 3. When the control circuit 2 detects reverse connection of the light source 3 in the detection mode, it stops supplying DC current from the lighting circuit 1 to the light source 3. [Selected Figure] Figure 1

Description

This disclosure generally relates to lighting devices and illumination devices, and more specifically to a lighting device that turns on a light source, and an illumination device that includes a lighting device.

Patent Document 1 describes an LED lighting device (lighting device) that includes an LED lighting device (lighting device) and an LED-equipped device (light source). The LED-equipped device has multiple LEDs (light-emitting elements) connected in series and a resistor connected in parallel to the multiple LEDs.

The LED lighting device outputs a DC voltage to the LED-equipped device that is lower than that during normal lighting during a predetermined period from the start of power supply to the LED-equipped device, and determines whether the LED-equipped device is reverse-connected based on the current flowing through the resistor. If the LED-equipped device is reverse-connected, the LED lighting device stops supplying power to the LED-equipped device.

JP 2012-174464 A

However, the LED lighting device (lighting device) described in Patent Document 1 does not detect reverse connection of an LED-equipped device (light source) by passing a current through multiple LEDs (light-emitting elements).

The objective of this disclosure is to provide a lighting device and illumination device that can detect reverse connection of a light source by passing a current through a light-emitting element.

A lighting device according to one aspect of the present disclosure includes a lighting circuit and a control circuit. The lighting circuit supplies a direct current to a light source having one or more light-emitting elements. The control circuit controls the lighting circuit. The control circuit has a detection mode in which a detection current smaller than the rated current of the lighting circuit is supplied from the lighting circuit to the light source during a detection period to detect reverse connection of the light source. When the control circuit detects reverse connection of the light source in the detection mode, it stops supplying the direct current from the lighting circuit to the light source.

The lighting device according to one aspect of the present disclosure includes the lighting device and the light source. The light-emitting element includes an LED and a protection element connected in parallel to the LED for protecting the LED.

According to a lighting device and an illumination device according to one aspect of the present disclosure, it is possible to detect reverse connection of a light source by passing a current through a light-emitting element.

FIG. 1 is a schematic circuit diagram of a lighting device and an illumination device according to an embodiment. FIG. 2 is a schematic circuit diagram of a light source of the above lighting device. 3A and 3B are waveform diagrams of an output voltage and an output current when a light source is normally connected to the lighting device of the above embodiment; 4A and 4B are waveform diagrams of an output voltage and an output current when a light source is reversely connected to the lighting device of the above embodiment; FIG. 5 is a flow chart showing the overall operation of the lighting device. FIG. 6 is a flow chart showing the operation of the lighting device in the detection mode. 7A and 7B are waveform diagrams of an output voltage and an output current when a light source is reversely connected to a lighting device according to a first modified example of the embodiment, respectively.

The lighting device and the illumination device according to the embodiment will be described below with reference to the drawings. Each figure described in the following embodiment is a schematic diagram, and the ratio of the size and thickness of each component does not necessarily reflect the actual dimensional ratio. Furthermore, the configuration described in the following embodiment is merely one example of the present disclosure. The present disclosure is not limited to the following embodiment, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

(Embodiment)
(1) Overview First, an overview of a lighting device 10 and an illumination device 100 according to the present embodiment will be described with reference to FIG. 1 and FIG. 2.

The lighting device 100 according to this embodiment performs spatial presentation using, for example, the illumination light emitted from the lighting device 100. The lighting device 100 is, for example, a floodlight (also called floodlighting or stadium lighting) installed in baseball fields, soccer fields, rugby fields, athletics stadiums, etc., and is used to illuminate the grounds and fields where athletes compete. However, the lighting device 100 may also be used in indoor facilities such as gymnasiums. In addition, the light color (color temperature) of the illumination light emitted from the lighting device 100 may be two or more types. As shown in FIG. 1, the lighting device 100 according to this embodiment includes a lighting device 10 and a light source 3. The lighting device 10 is a device for supplying lighting power to the light source 3.

In lighting devices used for such spatial presentations, for example, there are cases where the light source is required to be turned on and off instantly. For this reason, in conventional lighting devices, lighting power is supplied to the light source when the power is turned on. Therefore, for example, if the light-emitting element (LED) that constitutes the light source is reverse-connected, the lighting power is supplied to the light-emitting element in the reverse direction, which may damage the light-emitting element.

In order to solve the above problems, the lighting device 10 according to this embodiment includes a lighting circuit 1 and a control circuit 2, as shown in FIG. 1. The lighting circuit 1 supplies a direct current (output current I1) to the light source 3. The light source 3 has one or more light-emitting elements 31 (see FIG. 2). The control circuit 2 controls the lighting circuit 1. The control circuit 2 has a detection mode in which the control circuit 2 detects reverse connection of the light source 3 by supplying a detection current I11 (see FIG. 4B) smaller than the rated current of the lighting circuit 1 from the lighting circuit 1 to the light source 3 during a detection period T1 (see FIG. 4B). When the control circuit 2 detects reverse connection of the light source 3 in the detection mode, it stops supplying a direct current from the lighting circuit 1 to the light source 3.

In the lighting device 10 according to the present embodiment, in the detection mode, the control circuit 2 supplies the light source 3 with a detection current I11 that is smaller than the rated current of the lighting circuit 1. Therefore, compared to the case where a current larger than the detection current I11 is supplied to the light source 3, it is possible to suppress damage to the light emitting element 31. Also, for example, as shown in FIG. 2, when a protection element 312 (e.g., a Zener diode 313) is connected in parallel to the LED 311, when the detection current I11 is supplied to the light source 3, an overcurrent Ioc (see FIG. 4B) flows through the protection element 312. Therefore, it is possible to detect reverse connection of the light source 3 by detecting the overcurrent Ioc. That is, according to the lighting device 10 according to the present embodiment, it is possible to detect reverse connection of the light source 3 by passing the detection current I11 through the light emitting element 31.

(2) Details Next, the configurations of the lighting device 10 and the illumination device 100 according to the present embodiment will be described with reference to FIG. 1 and FIG.

As shown in FIG. 1, the lighting device 100 according to this embodiment includes a lighting device 10 and a light source 3.

(2.1) Light Source As shown in FIG. 2, the light source 3 has a plurality of light-emitting elements 31 (three in FIG. 2). Each of the plurality of light-emitting elements 31 includes an LED (Light-Emitting Diode) 311 and a protective element 312. The protective element 312 is connected in parallel with the LED 311. "The protective element 312 is connected in parallel with the LED 311" includes a case where the protective element 312 is simply connected in parallel with the LED 311 without considering the polarity (direction) of the protective element 312, and a case where the protective element 312 is connected in anti-parallel with the LED 311 while considering the polarity of the protective element 312. The protective element 312 is, for example, a Zener diode 313. The anode of the Zener diode 313 is connected to the cathode of the LED 311, and the cathode of the Zener diode 313 is connected to the anode of the LED 311. That is, the Zener diode 313 is connected in anti-parallel with the LED 311. The multiple light-emitting elements 31 are connected in series to each other between a first input terminal 32 and a second input terminal 33 described later. Therefore, a voltage obtained by multiplying the forward voltage of each LED 311 and the number of LEDs 311 (hereinafter also referred to as "forward voltage Vf of the light source 3") is applied between both ends of the light source 3 (the first input terminal 32, the second input terminal 33).

In the following description, when it is necessary to distinguish between multiple light-emitting elements 31, the light-emitting element 31 closest to the first input terminal 32 will be referred to as the "first light-emitting element 31", the light-emitting element 31 closest to the second input terminal 33 will be referred to as the "third light-emitting element 31", and the light-emitting element 31 between the first light-emitting element 31 and the third light-emitting element 31 will be referred to as the "second light-emitting element 31".

As shown in Figs. 1 and 2, the light source 3 further includes a first input terminal 32 and a second input terminal 33. The first input terminal 32 and the second input terminal 33 are terminals for inputting the output current I1 output from the lighting device 10. The output current I1 is, for example, a direct current (hereinafter also referred to as "direct current I1").

The first input terminal 32 is connected to the anode of the LED 311 of the first light-emitting element 31. The first input terminal 32 is also connected to the cathode of the Zener diode 313 of the first light-emitting element 31. The second input terminal 33 is connected to the cathode of the LED 311 of the third light-emitting element 31. The second input terminal 33 is also connected to the anode of the Zener diode 313 of the third light-emitting element 31.

(2.2) Lighting Device As shown in Fig. 1, the lighting device 10 includes a lighting circuit 1 and a control circuit 2. The lighting device 10 further includes a first output terminal 5 and a second output terminal 6. The lighting device 10 further includes a power supply unit. The power supply unit generates operating power for the control circuit 2 based on AC power supplied from an AC power supply 4.

(2.2.1) Lighting Circuit The lighting circuit 1 is a circuit that supplies a direct current I1 to the light source 3. As shown in FIG.

The rectifier circuit 11 is, for example, a diode bridge circuit having a plurality of diodes. In this embodiment, as an example, the rectifier circuit 11 is a full-wave rectifier circuit composed of four diodes. The rectifier circuit 11 receives an AC voltage from an AC power source 4 (for example, a commercial power source), full-wave rectifies the AC voltage, and outputs the full-wave rectified AC voltage.

The boost chopper circuit 12 boosts the output voltage of the rectifier circuit 11 to a desired voltage value. The boost chopper circuit 12 outputs the boosted DC voltage (hereinafter also referred to as the "boosted voltage") to the step-down chopper circuit 13.

The step-down chopper circuit 13 steps down the step-up voltage input from the step-up chopper circuit 12 to a desired voltage value, and outputs the stepped-down DC voltage (hereinafter also referred to as the "step-down voltage") to the light source 3. As shown in FIG. 1, the step-down chopper circuit 13 has a switching element Q1, a transformer Tr1, multiple (two in FIG. 1) capacitors C1 and C2, and multiple (three in FIG. 1) resistors R1 to R3.

The switching element Q1 is, for example, a metal-oxide-semiconductor field-effect transistor (MOSFET). The switching element Q1 has a first terminal, a second terminal, and a control terminal. In this embodiment, since the switching element Q1 is a MOSFET, the first terminal is the drain, the second terminal is the source, and the control terminal is the gate.

The first terminal of the switching element Q1 is connected to the high potential output terminal of the boost chopper circuit 12. The second terminal of the switching element Q1 is connected to the cathode of the diode D1. The anode of the diode D1 is connected to the low potential output terminal of the boost chopper circuit 12. That is, the switching element Q1 is connected between the output terminals of the boost chopper circuit 12 via the diode D1. In other words, the series circuit of the switching element Q1 and the diode D1 is connected between the output terminals of the boost chopper circuit 12. The control terminal of the switching element Q1 is connected to the control circuit 2.

Capacitor C1 is, for example, an electrolytic capacitor. Capacitor C1 has a positive terminal and a negative terminal. The positive terminal of capacitor C1 is connected to the high-potential output terminal of boost chopper circuit 12. The negative terminal of capacitor C1 is connected to the low-potential output terminal of boost chopper circuit 12. That is, capacitor C1 is connected between the output terminals of boost chopper circuit 12. Capacitor C1 smoothes the boosted voltage from boost chopper circuit 12.

The transformer Tr1 has a primary winding and a secondary winding. Each of the primary winding and the secondary winding is, for example, an inductor. That is, the transformer Tr1 includes two inductors. A first end of the primary winding is connected to the connection point between the switching element Q1 and the diode D1. A second end of the primary winding is connected to the first output terminal 5.

Like capacitor C1, capacitor C2 is an electrolytic capacitor and has a positive terminal and a negative terminal. The positive terminal of capacitor C2 is connected to the second end of the primary winding of transformer Tr1. The negative terminal of capacitor C2 is connected to the low-potential output terminal of boost chopper circuit 12. Capacitor C2 smoothes the output voltage of the primary winding of transformer Tr1.

The first end of the resistor R1 is connected to the second end of the primary winding of the transformer Tr1. The second end of the resistor R1 is connected to the first end of the resistor R2. The second end of the resistor R2 is connected to the low-potential output terminal of the boost chopper circuit 12. That is, the series circuit of the resistors R1 and R2 is connected between the second end of the primary winding of the transformer Tr1 and the low-potential output terminal of the boost chopper circuit 12. In the step-down chopper circuit 13, as shown in FIG. 1, the connection point between the resistors R1 and R2 is connected to the control circuit 2. The control circuit 2 detects the output voltage V1 of the lighting circuit 1 by detecting the voltage V2 between both ends of the resistor R2. Here, the output voltage V1 of the lighting circuit 1 is a voltage applied between the first output terminal 5 and the second output terminal 6 described later, as shown in FIG. 1. Therefore, in the example of FIG. 1, the output voltage V1 of the lighting circuit 1 is also a voltage applied to the light source 3 (hereinafter, also referred to as the "applied voltage V1").

The first end of resistor R3 is connected to the second output terminal 6. The second end of resistor R3 is connected to the low-potential output terminal of the step-up chopper circuit 12. In the step-down chopper circuit 13, as shown in FIG. 1, the first end of resistor R3 is connected to the control circuit 2. The control circuit 2 detects the voltage V3 across resistor R3 to detect the current I1 flowing through the light source 3 (hereinafter also referred to as the "output current I1" of the lighting circuit 1).

(2.2.2) Control Circuit The control circuit 2 may be realized, for example, by a computer system having one or more processors and one or more memories. In the lighting device 10, the one or more processors execute a program recorded in the memory, thereby realizing the functions of the control circuit 2. The program may be pre-recorded in the memory, may be provided via a telecommunications line such as the Internet, or may be provided by recording it on a non-transitory recording medium such as a memory card.

The control circuit 2 controls the lighting circuit 1. More specifically, the control circuit 2 controls the step-up chopper circuit 12 and the step-down chopper circuit 13 so that the DC current I1 supplied from the lighting circuit 1 to the light source 3 has a desired current value. As described above, the control circuit 2 is connected to the control terminal of the switching element Q1 of the step-down chopper circuit 13. The control circuit 2 is also connected to a dimmer. The dimmer is a device for setting the dimming rate of the light source 3. The dimmer outputs a dimming signal corresponding to the dimming rate to the control circuit 2. The dimming signal is, for example, a PWM (Pulse Width Modulation) signal.

The control circuit 2 sets a target voltage based on the dimming signal from the dimmer. The target voltage is a voltage corresponding to the target value of the output current I1 of the lighting circuit 1. In this way, the output current I1 of the lighting circuit 1 is determined by the dimming signal input from the dimmer. Then, the control circuit 2 outputs a drive signal to the switching element Q1 of the step-down chopper circuit 13 and controls the step-up chopper circuit 12 so that the output voltage V1 (see FIG. 3A) of the lighting circuit 1 matches the target voltage (for example, the forward voltage Vf of the light source 3). That is, the control circuit 2 controls the lighting circuit 1 (the step-up chopper circuit 12 and the step-down chopper circuit 13) based on the dimming signal indicating the dimming level of the light source 3.

The control circuit 2 also has a detection mode for detecting reverse connection of the light source 3. "Reverse connection of the light source 3" refers to a state in which the positive output terminal of the lighting device 10 is connected to the negative input terminal of the light source 3, and the negative output terminal of the lighting device 10 is connected to the positive input terminal of the light source 3. More specifically, it refers to a state in which the first output terminal 5 of the lighting device 10 is connected to the second input terminal 33 of the light source 3, and the second output terminal 6 of the lighting device 10 is connected to the first input terminal 32 of the light source 3. That is, each of the multiple light-emitting elements 31 is an element having polarity (plus and minus). In the detection mode, the control circuit 2 controls the lighting circuit 1 during the detection period T1 (see FIG. 4B) to supply the detection current I11 to the light source 3. The detection current I11 is a current smaller than the rated current of the lighting circuit 1. More specifically, the detection current I11 is a current that does not light the light-emitting element 31 (LED 311) when the light-emitting element 31 is normally connected, and is less than the absolute maximum rating of the reverse current Ir (see FIG. 7B) of the light-emitting element 31 (LED 311). In this embodiment, as an example, the detection current I11 is a current that is 0.1% of the rated current of the lighting circuit 1.

Here, for example, assume that the light source 3 is reverse-connected to the lighting device 10. In this embodiment, the Zener diode 313 is connected in reverse parallel to the LED 311. Therefore, when the detection current I11 is supplied to the light source 3, an overcurrent Ioc (see FIG. 4B) flows in the reverse direction through the Zener diode 313. Therefore, the control circuit 2 can detect the reverse connection of the light source 3 by detecting the overcurrent Ioc. That is, in the detection mode, the control circuit 2 detects the reverse connection of the light source 3 based on the current (overcurrent Ioc) flowing through the light source 3. In this case, the control circuit 2 determines whether the above current in the detection period T1 is equal to or greater than the first threshold Ith (see FIG. 4B), and detects the reverse connection of the light source 3 when the above current is equal to or greater than the first threshold Ith.

When the control circuit 2 detects reverse connection of the light source 3 in the detection mode, it stops the supply of DC current I1 from the lighting circuit 1 to the light source 3.

Here, the control circuit 2 executes the detection mode when the control circuit 2 is started. That is, the control circuit 2 executes the detection mode at the timing when the control circuit 2 is started upon receiving power supply from the AC power source 4. That is, the detection period T1 is a fixed period starting from the start of the control circuit 2. In addition, if the detection period T1 is long, the period during which the light source 3 is not lit will be long, so it is preferable that the detection period T1 is 1 second or less. Furthermore, taking into account the operation time of the control circuit 2, it is preferable that the detection period T1 is 20 milliseconds (0.02 seconds) or more. That is, it is preferable that the detection period T1 is 20 milliseconds or more and 1 second or less. In this embodiment, as an example, the detection period T1 is 500 milliseconds. Note that the detection period T1 may be a fixed value, but may also be a variable value. That is, the lighting device 10 may be configured to be able to change the detection period T1.

(2.2.3) Output Terminals The first output terminal 5 and the second output terminal 6 are terminals for outputting the DC current I1 generated by the lighting device 10. As described above, the first output terminal 5 is connected to the second end of the primary winding of the transformer Tr1. The second output terminal 6 is connected to the low potential side output terminal of the boost chopper circuit 12 via the resistor R3.

When the light source 3 is normally connected to the lighting device 10, the first output terminal 5 is connected to the first input terminal 32, and the second output terminal 6 is connected to the second input terminal 33. When the light source 3 is reversely connected to the lighting device 10, the first output terminal 5 is connected to the first input terminal 32, and the second output terminal 6 is connected to the second input terminal 33.

(3) Output Characteristics Next, the output characteristics of the lighting device 10 according to this embodiment will be described with reference to Figures 3A to 4B. In Figures 3A and 4A, the horizontal axis represents time, and the vertical axis represents the output voltage V1 of the lighting device 10. In Figures 3B and 4B, the horizontal axis represents time, and the vertical axis represents the output current I1 of the lighting device 10. As described above, the output voltage V1 of the lighting circuit 1 is a voltage applied between the first output terminal 5 and the second output terminal 6, and is therefore also the applied voltage V1 applied to the light source 3. In addition, the output current I1 of the lighting circuit 1 is also a current flowing through the light source 3.

(3.1) Output Characteristics in Normal Connection First, the output characteristics when the light source 3 is normally connected to the lighting device 10 will be described with reference to Figures 3A and 3B. In this embodiment, a detection period T1, a rapid charging period T2, and a dimming output period T3 are provided before the lighting device 10 turns on the light source 3 with a predetermined dimming output. As described above, the detection period T1 is a period for detecting reverse connection of the light source 3. That is, the detection period T1 is a period during which the detection mode of the control circuit 2 is executed. The rapid charging period T2 is a period for rapid charging the power supplied to the light source 3. The dimming output period T3 is a period during which the light source 3 is turned on with a dimming output corresponding to the above-mentioned dimming rate.

In FIG. 3A, the change in output voltage V1 when the dimming output is relatively high is shown by a solid line, and the change in output voltage V1 when the dimming output is relatively low is shown by a dashed line. Also, in FIG. 3B, the change in output current I1 when the dimming output is relatively high is shown by a solid line, and the change in output current I1 when the dimming output is relatively low is shown by a dashed line.

As shown by the solid line in FIG. 3B, the lighting circuit 1 outputs a detection current I11 to the light source 3 during the detection period T1. In this embodiment, a resistor R3 is connected in series with the light source 3. Therefore, as shown by the solid line in FIG. 3A, the output voltage V1 of the lighting circuit 1 increases linearly.

When the dimming output is relatively high, the lighting circuit 1 outputs a current I12 corresponding to the dimming output at time t1 when the detection period T1 has elapsed, as shown by the solid line in FIG. 3B. As a result, during the fast charging period T2, the output voltage V1 of the lighting circuit 1 increases rapidly toward the forward voltage Vf of the light source 3, as shown by the solid line in FIG. 3A, and reaches the forward voltage Vf at time t2.

On the other hand, when the dimming output is relatively low, the lighting circuit 1 outputs a current I13 larger than the current I14 at time t1 when the detection period T1 has elapsed, because the dimming output is lower than the preset value, as shown by the dashed line in FIG. 3B. The current I14 is a current corresponding to the dimming output. As a result, during the fast charging period T2, the output voltage V1 of the lighting circuit 1 increases toward the forward voltage Vf of the light source 3, as shown by the dashed line in FIG. 3A. Note that the change (slope) of the output voltage V1 when the dimming output is relatively low is smaller than the change (slope) of the output voltage V1 when the dimming output is relatively high (see FIG. 3A).

When the dimming output is relatively high, the output voltage V1 of the lighting circuit 1 reaches the forward voltage Vf at time t2 during the fast charging period T2, as shown by the solid line in FIG. 3A. Therefore, the light source 3 lights up at a predetermined dimming output after time t2.

On the other hand, when the dimming output is relatively low, the output voltage V1 of the lighting circuit 1 reaches the forward voltage Vf at time t4 during the dimming output period T3, as shown by the dashed line in FIG. 3A. Therefore, the light source 3 lights up at a predetermined dimming output after time t4.

(3.2) Output characteristics when reversely connected Next, a case where the light source 3 is reversely connected to the lighting device 10 will be described with reference to FIGS. 4A and 4B. In this embodiment, as described above, in each light-emitting element 31, the Zener diode 313 is connected in reverse parallel to the LED 311. Therefore, when the detection current I11 is supplied to the light source 3 during the detection period T1, as shown in FIG. 4B, the overcurrent Ioc flows in the reverse direction through the Zener diode 313. As shown in FIG. 4B, the overcurrent Ioc exceeds the first threshold Ith, so that the control circuit 2 can detect the reverse connection of the light source 3 when the overcurrent Ioc is equal to or greater than the first threshold Ith. Here, in this embodiment, the control circuit 2 detects the voltage V3 across the resistor R3 as the output current I1 of the lighting circuit 1. Therefore, the control circuit 2 detects the reverse connection of the light source 3 when the voltage V3 across the light source 3 is equal to or greater than the threshold corresponding to the first threshold Ith.

When an overcurrent Ioc flows through the Zener diode 313, as shown in FIG. 4A, the output voltage V1 of the lighting circuit 1 exceeds the threshold value Vth, and the control circuit 2 may detect reverse connection of the light source 3 based on the output voltage V1 being equal to or greater than the threshold value Vth.

When the control circuit 2 detects that the light source 3 is reversely connected, it stops the supply of DC current I1 from the lighting circuit 1 to the light source 3. As a result, as shown in FIG. 4B, the output current I1 of the lighting circuit 1 becomes zero. Also, as shown in FIG. 4A, the output voltage V1 of the lighting circuit 1 also becomes zero.

(4) Operation Next, the operation of the lighting device 10 according to the present embodiment will be described with reference to FIGS.

(4.1) Overall Operation First, the overall operation of the lighting device 10 will be described with reference to FIG.

When an AC voltage is input from the AC power source 4 to the lighting device 10, the power supply unit generates operating power for the control circuit 2. When the operating power generated by the power supply unit is supplied to the control circuit 2, the control circuit 2 is initialized (step S1). Next, the control circuit 2 detects that the AC power source 4 is on because the operating power has been supplied (step S2). After that, the control circuit 2 executes a detection mode to detect reverse connection of the light source 3 (step S3). If the light source 3 is not reversely connected to the lighting device 10, that is, if the light source 3 is normally connected to the lighting device 10 (step S3: No), the control circuit 2 controls the lighting circuit 1 so that the output current I1 of the lighting circuit 1 becomes a dimming output corresponding to the dimming signal from the dimmer (step S4).

If the control circuit 2 does not detect an abnormality during control of the lighting circuit 1 (step S5: No), it detects whether the AC power supply 4 is off or not (step S6). If the AC power supply 4 is not off (step S6: No), the control circuit 2 repeats steps S4 to S6. If the AC power supply 4 is off (step S6: Yes), the control circuit 2 returns to step S1.

If the control circuit 2 detects a reverse connection of the light source 3 (step S3: Yes) or detects an abnormality during control of the lighting circuit 1 (step S5: Yes), it stops the lighting circuit 1 (step S7).

Here, the "abnormality" in step S5 is an abnormality that occurs when the light source 3 is normally connected to the lighting device 10. Specifically, the abnormality includes, for example, at least one of the multiple LEDs 311 being open, all of the multiple LEDs 311 being shorted, and a circuit abnormality in the lighting circuit 1, etc. As described above, the control circuit 2 also stops the lighting circuit 1 when an abnormality is detected in step S5.

(4.2) Detection Mode Next, the detection mode of the control circuit 2 will be described with reference to FIG.

When the detection mode is started by step S3 (see FIG. 5) described above, the control circuit 2 determines whether the first time has elapsed (step S11). The first time is a time corresponding to a mask period that is set so that the output voltage V1 of the lighting circuit 1 is not detected until the output voltage V1 reaches a predetermined value. If the first time has not elapsed (step S11: No), the control circuit 2 waits until the first time has elapsed. When the first time has elapsed (step S11: Yes), the control circuit 2 causes the lighting circuit 1 to supply the detection current I11 to the light source 3 (step S12).

Next, the control circuit 2 detects the output voltage V1 and the output current (current flowing through the light source 3) I1 of the lighting circuit 1 (step S13). At this time, the control circuit 2 detects the output voltage V1 based on the voltage V2 across the resistor R2. The control circuit 2 also detects the output current I1 based on the voltage V3 across the resistor R3. Then, the control circuit 2 determines whether the output current I1 is equal to or greater than the first threshold Ith (see FIG. 4B) (step S14). In this embodiment, since the Zener diode 313 is connected in inverse parallel to the LED 311, the output current I1 becomes an overcurrent Ioc (see FIG. 4B) and exceeds the first threshold Ith.

If the output current I1 is not equal to or greater than the first threshold Ith (step S14: No), the control circuit 2 starts measuring time (step S15). If the measured time has not reached the detection time (step S16: No), the control circuit 2 repeats steps S11 to S16. If the measured time reaches the detection time (step S16: Yes), the control circuit 2 controls the lighting circuit 1 so that the output current I1 of the lighting circuit 1 becomes a dimming output corresponding to the dimming signal from the dimmer (step S17). The detection time is a time equivalent to the detection period T1 described above.

If the output current I1 is equal to or greater than the first threshold Ith (step S14: Yes), the control circuit 2 stops the lighting circuit 1 (step S18).

(5) Effects In the lighting device 10 according to the present embodiment, for example, as shown in Fig. 2, when the protection element 312 (e.g., Zener diode 313) is connected in inverse parallel to the LED 311, if the light source 3 is reverse-connected to the lighting device 1, the detection current I11 is supplied to the light source 3, causing an overcurrent Ioc to flow through the protection element 312. For this reason, it is possible to detect reverse connection of the light source 3 by detecting the overcurrent Ioc. That is, according to the lighting device 10 according to the present embodiment, it is possible to detect reverse connection of the light source 3 by flowing the detection current I11 to the light-emitting element 31.

Furthermore, in the lighting device 10 according to this embodiment, reverse connection of the light source 3 can be detected simply by supplying the detection current I11 to the light source 3. In particular, in the lighting device 10 according to this embodiment, reverse connection of the light source 3 can be detected simply by determining whether the output current (current flowing through the light source 3) I1 is equal to or greater than the first threshold Ith.

In addition, in the lighting device 10 according to this embodiment, the detection period T1 is 1 second or less (e.g., 500 milliseconds), and when the light source 3 is normally connected to the lighting device 1, it is possible to shorten the time during which the light source 3 is not lit.

In addition, in the lighting device 10 according to this embodiment, the detection current I11 is a value that does not cause the light-emitting element 31 to light up when the light-emitting element 31 is normally connected, and is less than the absolute maximum rating of the reverse current Ir of the light-emitting element 31. This makes it possible to prevent damage to the light-emitting element 31 while suppressing unnecessary lighting of the light-emitting element 31 in the detection mode.

In addition, in the lighting device 10 according to this embodiment, the control circuit 2 controls the lighting circuit 1 based on a dimming signal indicating the dimming level of the light source 3. This makes it possible to light the light source 3 at a dimming level according to the dimming signal.

In addition, in the lighting device 10 according to this embodiment, a protection element 312 is connected in parallel to the LED 311. In addition, in the lighting device 10 according to this embodiment, the protection element 312 is a Zener diode 313 connected in anti-parallel to the LED 311. This makes it possible to detect reverse connection of the light source 3 by detecting the overcurrent Ioc flowing through the Zener diode 313 by the detection current I11.

(6) Modifications The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the above-described embodiment are listed below. The modifications described below can be applied in appropriate combination.

(6.1) Modification 1
Hereinafter, the lighting device 10 and the illumination device 100 according to the modified example 1 will be described with reference to Fig. 7A and Fig. 7B. Regarding the lighting device 10 and the illumination device 100 according to the modified example 1, the same components as those of the lighting device 10 and the illumination device 100 according to the above-described embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

In the above embodiment, as shown in FIG. 2, the protective element 312 (e.g., the Zener diode 313) is connected in anti-parallel to the LED 311, but the protective element 312 may be omitted. That is, the light-emitting element 31 may include only the LED 311.

When the light emitting element 31 includes only the LED 311, when the light source 3 is connected in inverse parallel to the lighting device 10, the detection current I11 flows from the cathode to the anode of the LED 311 (see FIG. 7B). As a result, as shown in FIG. 7A, an applied voltage V1 smaller than the reverse voltage Vr of the LED 311 is applied between both ends of the light source 3. Therefore, the control circuit 2 can detect the reverse connection of the light source 3 because the applied voltage V1 of the light source 3 is smaller than the reverse voltage Vr. In other words, the control circuit 2 detects the reverse connection of the light source 3 based on the voltage applied to the light source 3 (applied voltage V1). In the first modification, the reverse voltage Vr is the second threshold (hereinafter also referred to as the "second threshold Vr").

Here, in the first modification, a mask period is provided until the output voltage V1 of the lighting circuit 1 reaches a certain voltage. In the example of FIG. 7A, the first period T11 is the mask period. Therefore, the control circuit 2 does not determine whether the applied voltage V1 of the light source 3 is equal to or greater than the second threshold Vr in the first period T11. This makes it possible to suppress erroneous determination of the applied voltage V1. Then, in the second period T12, the control circuit 2 determines whether the applied voltage V1 of the light source 3 is equal to or less than the second threshold Vr, and detects reverse connection of the light source 3 when the applied voltage V1 is equal to or less than the second threshold Vr. Note that the detection current I11 supplied to the light source 3 in the first period T11 is less than the absolute maximum rating of the reverse current Ir of the light source 3, as shown in FIG. 7B.

As described above, the first period T11 is a mask period, and is a period that begins at the start of the detection period T1. The second period T12 is a period different from the first period T11 in the detection period T1, and is a period that follows the first period T11. In the example of FIG. 7A, the end point of the first period T11 and the start point of the second period T12 coincide with each other, and the first period T11 and the second period T12 are continuous. In other words, the detection period T1 includes the first period T11 and the second period T12.

In the lighting device 10 and the illumination device 100 according to the first modification, it is also possible to detect reverse connection of the light source 3 by passing a current (detection current I11) through the light source 3.

In the first modification, the first period T11 and the second period T12 are continuous, but the first period T11 and the second period T12 do not have to be continuous. In other words, the end point of the first period T11 and the start point of the second period T12 do not have to coincide.

(6.2) Other Modifications Other modifications are listed below.

In the above embodiment, the lighting device 100 is a stage lighting device, but the lighting device 100 is not limited to stage lighting devices and may be, for example, general lighting devices (e.g., downlights).

In the above embodiment, the light source 3 has three light-emitting elements 31, but the light source 3 may have, for example, one, two, or four or more light-emitting elements 31. In other words, the light source 3 may have one or more light-emitting elements 31.

In the above embodiment, the three light-emitting elements 31 are connected in series to each other, but the three light-emitting elements 31 may be connected in parallel to each other, or in series-parallel to each other, for example.

In the above embodiment, the detection current I11 is 0.1% of the rated current of the lighting circuit 1, but the detection current I11 may be, for example, 0.1% or less of the rated current of the lighting circuit 1. More preferably, the detection current I11 is, for example, 0.2% or less of the rated current of the lighting circuit 1.

In the above embodiment, the protection element 312 is a Zener diode 313, but the protection element 312 is not limited to the Zener diode 313 and may be, for example, a diode. In this case, the diode is connected in inverse parallel to the LED 311.

(Aspects)
The present specification discloses the following aspects.

The lighting device (10) according to the first aspect includes a lighting circuit (1) and a control circuit (2). The lighting circuit (1) supplies a direct current (I1) to a light source (3) having one or more light-emitting elements (31). The control circuit (2) controls the lighting circuit (1). The control circuit (2) has a detection mode in which the control circuit (2) supplies a detection current (I11) smaller than the rated current of the lighting circuit (1) from the lighting circuit (1) to the light source (3) during a detection period (T1) to detect reverse connection of the light source (3). When the control circuit (2) detects reverse connection of the light source (3) in the detection mode, it stops supplying the direct current (I1) from the lighting circuit (1) to the light source (3).

According to this aspect, for example, when the protection element (312) is connected in inverse parallel to the LED (311), if the light source (3) is reversely connected to the lighting device (1), the detection current (I11) is supplied to the light source (3), causing an overcurrent (Ioc) to flow through the protection element (312). On the other hand, if the light source (3) is normally connected to the lighting device (10), no current flows through the light-emitting element (31). Therefore, by detecting the overcurrent (Ioc), it is possible to detect reverse connection of the light source (3). In other words, according to this aspect, it is possible to detect reverse connection of the light source (3) by passing a current through the light-emitting element (31).

In the lighting device (10) according to the second aspect, in the first aspect, the control circuit (2) detects reverse connection of the light source (3) in the detection mode based on at least one of the current (I1) flowing through the light source (3) and the voltage (V1) applied to the light source (3).

According to this aspect, it is possible to detect reverse connection of the light source (3) simply by detecting at least one of the current (I1) flowing through the light source (3) and the voltage (V1) applied to the light source (3).

In the lighting device (10) according to the third aspect, in the second aspect, the control circuit (2) detects reverse connection of the light source (3) when at least one of the following conditions is satisfied: the current (I1) is equal to or greater than the first threshold (Ith) and the voltage (V1) is equal to or less than the second threshold (Vr).

According to this aspect, it is possible to detect reverse connection of the light source (3) simply by comparing the current (I1) with the first threshold (Ith) and/or comparing the voltage (V1) with the second threshold (Vr).

In the lighting device (10) according to the fourth aspect, in the third aspect, the control circuit (2) determines whether the current (I1) is equal to or greater than the first threshold value (Ith) during the detection period (T1).

According to this aspect, it is possible to detect reverse connection of the light source (3) simply by determining whether the current (I1) is equal to or greater than the first threshold (Ith).

In the lighting device (10) according to the fifth aspect, in the third aspect, the detection period (T1) includes a first period (T11) and a second period (T12). The first period (T11) is a period that starts at the start of the detection period (T1). The second period (T12) is a period different from the first period (T11) in the detection period (T1) and is a period that comes after the first period (T11). The control circuit (2) does not determine whether the voltage (V1) is equal to or lower than the second threshold (Vr) during the first period (T11), but determines whether the voltage (V1) is equal to or lower than the second threshold (Vr) during the second period (T12).

This aspect makes it possible to suppress erroneous judgments due to voltage (V1).

In the lighting device (10) according to the sixth aspect, in any one of the first to fifth aspects, the detection period (T1) is a fixed period that begins when the control circuit (2) is started.

This aspect makes it possible to reduce the time required for detection mode compared to when detection mode is executed periodically.

In the lighting device (10) according to the seventh aspect, in any one of the first to sixth aspects, the detection period (T1) is 1 second or less.

According to this aspect, when the light source (3) is normally connected to the lighting device (1), it is possible to shorten the time during which the light source (3) is not lit.

In the lighting device (10) according to the eighth aspect, in any one of the first to seventh aspects, the detection current (I11) is a magnitude that does not cause the light-emitting element (31) to light up when the light-emitting element (31) is normally connected, and is less than the absolute maximum rating of the reverse current (Ir) of the light-emitting element (31).

According to this aspect, it is possible to prevent damage to the light-emitting element (31) while preventing unnecessary lighting of the light-emitting element (31) in the detection mode.

In the lighting device (10) according to the ninth aspect, in any one of the first to eighth aspects, the control circuit (2) controls the lighting circuit (1) based on a dimming signal indicating the dimming level of the light source (3).

According to this embodiment, it is possible to light the light source (3) at a dimming level according to the dimming signal.

In the lighting device (10) according to the tenth aspect, in any one of the first to ninth aspects, the light-emitting element (31) includes an LED (311) and a protective element (312). The protective element (312) is connected in parallel with the LED (311). The protective element (312) is an element for protecting the LED (311).

According to this aspect, it is possible to pass an overcurrent (Ioc) through the protection element (312).

In the lighting device (10) according to the eleventh aspect, in the tenth aspect, the protection element (312) is a Zener diode (313) connected in anti-parallel to the LED (311).

According to this embodiment, it is possible to pass an overcurrent (Ioc) through the Zener diode (313).

The lighting device (100) according to the twelfth aspect includes a lighting device (10) according to any one of the first to eleventh aspects and a light source (3). The light-emitting element (31) includes an LED (311) and a protective element (312). The protective element (312) is connected in parallel with the LED (311). The protective element (312) is an element for protecting the LED (311).

According to this aspect, for example, when the protection element (312) is connected in inverse parallel to the LED (311), if the light source (3) is reversely connected to the lighting device (1), the detection current (I11) is supplied to the light source (3), causing an overcurrent (Ioc) to flow through the protection element (312). On the other hand, if the light source (3) is normally connected to the lighting device (10), no current flows through the light-emitting element (31). Therefore, by detecting the overcurrent (Ioc), it is possible to detect reverse connection of the light source (3). In other words, according to this aspect, it is possible to detect reverse connection of the light source (3) based on the current flowing through the light-emitting element (31).

The configurations according to the second to eleventh aspects are not essential to the lighting device (10) and may be omitted as appropriate.

1 Lighting circuit 2 Control circuit 3 Light source 10 Lighting device 31 Light emitting element 100 Illumination device 311 LED
312 Protection element 313 Zener diode I1 Output current (DC current, current)
I11 Detection current Ir Reverse current Ith First threshold T1 Detection period T11 First period T12 Second period V1 Output voltage (voltage)
Vr Reverse voltage (second threshold)

Claims (12)

A lighting circuit for supplying a direct current to a light source having one or more light emitting elements;
A control circuit for controlling the lighting circuit,
the control circuit has a detection mode in which a detection current smaller than a rated current of the lighting circuit is supplied from the lighting circuit to the light source during a detection period to detect reverse connection of the light source;
When the control circuit detects reverse connection of the light source in the detection mode, the control circuit stops the supply of the DC current from the lighting circuit to the light source.
Lighting device. The control circuit detects reverse connection of the light source based on at least one of a current flowing through the light source and a voltage applied to the light source in the detection mode.
The lighting device according to claim 1 . The control circuit detects reverse connection of the light source when at least one of a condition that the current is equal to or greater than a first threshold and a condition that the voltage is equal to or less than a second threshold is satisfied.
The lighting device according to claim 2. The control circuit determines whether the current is equal to or greater than the first threshold during the detection period.
The lighting device according to claim 3. The detection period is:
A first period starting from a start time of the detection period;
a second period that is different from the first period in the detection period and that is subsequent to the first period;
the control circuit does not determine whether the voltage is equal to or lower than the second threshold during the first period, and determines whether the voltage is equal to or lower than the second threshold during the second period.
The lighting device according to claim 3. The detection period is a fixed period starting from the start of the control circuit.
The lighting device according to any one of claims 1 to 5. The detection period is 1 second or less.
The lighting device according to any one of claims 1 to 5. The detection current is a current that does not light the light-emitting element when the light-emitting element is normally connected, and is less than the absolute maximum rating of the reverse current of the light-emitting element.
The lighting device according to any one of claims 1 to 5. The control circuit controls the lighting circuit based on a dimming signal indicating a dimming level of the light source.
The lighting device according to any one of claims 1 to 5. The light-emitting element is
LEDs,
A protection element connected in parallel with the LED for protecting the LED.
The lighting device according to any one of claims 1 to 5. The protection element is a Zener diode connected in anti-parallel to the LED.
The lighting device according to claim 10. A lighting device according to any one of claims 1 to 5,
The light source,
The light-emitting element is
LEDs,
A protection element connected in parallel with the LED for protecting the LED.
Lighting equipment.

Images