Lighting device and luminaire

Abstract

To reduce loss.SOLUTION: The lighting device 1 includes a first conversion circuit 14, a second conversion circuit 15, a control circuit 17, and a power supply 16. The first conversion circuit 14 converts the first DC voltage V1 into a second DC voltage V2. The second conversion circuit 15 converts the second DC voltage V2 into a third DC voltage V3. The control circuit 17 controls the first conversion circuit 14 and the second conversion circuit 15. The power supply unit 16 supplies an operating voltage Vm to the control circuit 17. The power supply unit 16 includes a power supply circuit 161 that generates a fourth DC voltage V2 based on the second DC voltage V4 output from the first conversion circuit 14. The power supply unit 16 supplies at least one of the fourth DC voltage V4 outputted from the power supply circuit 161 and the fifth DC voltage V5 outputted from the second conversion circuit 15 to the control circuit 17 as the operating voltage Vm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a lighting device and a lighting fixture. More particularly, the present disclosure relates to a lighting device including a plurality of conversion circuits and a lighting fixture including the lighting device. [Background technology]

[0002] Patent Document 1 describes a lighting fixture including an LED light source and a lighting device that supplies power to the LED light source. The lighting device includes a rectifier circuit, a boost circuit, a control circuit, a control power supply circuit, a first power supply means, and a second power supply means. The rectifier circuit receives power from an AC power supply. The boost circuit has a switching element and a smoothing capacitor, and boosts the pulsating voltage output from the rectifier circuit. The control circuit controls the switching element. The control power supply circuit supplies power to the control circuit. The first power supply means supplies the output voltage of the rectifier circuit to a power supply terminal of the control power supply circuit. The second power supply means supplies the charging voltage of the smoothing capacitor to the power supply terminal of the control power supply circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-104160 Summary of the Invention [Problem to be solved by the invention]

[0004] The lighting device described in Patent Document 1 has a problem in that it supplies both the output voltage of the rectifier circuit and the charging voltage of the smoothing capacitor to the control power supply circuit (power supply circuit), resulting in large losses.

[0005] An object of the present disclosure is to provide a lighting device and a lighting fixture that can reduce losses. [Means for solving the problem]

[0006] A lighting device according to one aspect of the present disclosure includes a first conversion circuit, a second conversion circuit, a control circuit, and a power supply unit. The first conversion circuit converts a first DC voltage into a second DC voltage different from the first DC voltage. The second conversion circuit converts the second DC voltage output from the first conversion circuit into a third DC voltage different from the second DC voltage. The control circuit controls the first conversion circuit and the second conversion circuit. The power supply unit supplies an operating voltage to the control circuit. The power supply unit includes a power supply circuit that generates a fourth DC voltage based on the second DC voltage output from the first conversion circuit. The power supply unit supplies at least one of the fourth DC voltage output from the power supply circuit and a fifth DC voltage output from the second conversion circuit to the control circuit as the operating voltage.

[0007] A lighting fixture according to an aspect of the present disclosure includes the lighting device and a light source unit, wherein the light source unit is lit by the third DC voltage supplied from the lighting device. [Effects of the Invention]

[0008] According to a lighting device and a lighting fixture according to an aspect of the present disclosure, it is possible to reduce losses. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a lighting device and a lighting fixture according to an embodiment. [Figure 2] FIG. 2 is a partial configuration diagram of a second conversion circuit in the lighting device. [Figure 3] FIG. 3 is a timing chart illustrating the operation of the lighting device. [Figure 4] FIG. 4 is a schematic configuration diagram of a lighting device and a lighting fixture according to a first modification of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, lighting devices and lighting fixtures according to embodiments will be described with reference to the drawings. The drawings referred to in the following embodiments are schematic diagrams, and the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensions, and the size and thickness ratios between the components do not necessarily reflect the actual dimensional ratios.

[0011] (Embodiment) (1) Overview First, an overview of a lighting device 1 and a lighting fixture 10 according to an embodiment will be described with reference to FIG.

[0012] 1, a lighting fixture 10 according to this embodiment includes a lighting device 1 and a light source unit 2. The light source unit 2 is turned on by a third DC voltage V3 supplied from the lighting device 1.

[0013] As shown in FIG. 1 , the lighting device 1 according to the embodiment includes a first conversion circuit 14, a second conversion circuit 15, a control circuit 17, and a power supply unit 16. The first conversion circuit 14 converts a first DC voltage V1 into a second DC voltage V2 different from the first DC voltage V1. The second conversion circuit 15 converts the second DC voltage V2 output from the first conversion circuit 14 into a third DC voltage V3 different from the second DC voltage V2. The control circuit 17 controls the first conversion circuit 14 and the second conversion circuit 15. The power supply unit 16 supplies an operating voltage Vm to the control circuit 17. The power supply unit 16 includes a power supply circuit 161 that generates a fourth DC voltage V4 based on the second DC voltage V2 output from the first conversion circuit 14. The power supply unit 16 supplies at least one of the fourth DC voltage V4 output from the power supply circuit 161 and a fifth DC voltage V5 output from the second conversion circuit 15 to the control circuit 17 as the operating voltage Vm.

[0014] In the lighting device 1 and the lighting fixture 10 according to the embodiment, at least one of the fourth DC voltage V4 and the fifth DC voltage V5 is supplied to the control circuit 17, which makes it possible to reduce losses.

[0015] (2)Details Next, each component of the lighting device 1 and the lighting fixture 10 according to the embodiment will be described with reference to FIGS.

[0016] The lighting fixture 10 according to the embodiment is, for example, a ceiling-mounted lighting fixture that is directly attached to a ceiling. However, the lighting fixture 10 may also be a ceiling-recessed lighting fixture that is recessed into a ceiling. Furthermore, the lighting fixture 10 may be directly attached to a wall or recessed into a wall.

[0017] 1, a lighting fixture 10 according to this embodiment includes a lighting device 1 and a light source unit 2. The light source unit 2 is turned on by a third DC voltage V3 supplied from the lighting device 1.

[0018] (2.1) Lighting device 1, the lighting device 1 includes an input unit 11, an output unit 12, a rectifier circuit 13, a first conversion circuit 14, a second conversion circuit 15, a power supply unit 16, and a control circuit 17. The lighting device 1 further includes an adjustment circuit 18.

[0019] (2.1.1) Input section 1, the input unit 11 includes a pair of input terminals 111 and 112. The pair of input terminals 111 and 112 are connected to an AC power supply 3, and an AC voltage Vin is input from the AC power supply 3.

[0020] (2.1.2) Output section 1, the output unit 12 includes a pair of output terminals 121 and 122. The pair of output terminals 121 and 122 are connected to the light source unit 2, and output (supply) a third DC voltage V3 to the light source unit 2.

[0021] (2.1.3) Rectifier circuit The rectifier circuit 13 is, for example, a full-wave rectifier circuit configured by connecting four diodes in a bridge configuration. The rectifier circuit 13 is connected to the AC power supply 3 via a pair of input terminals 111, 112, and rectifies the AC voltage Vin supplied from the AC power supply 3 into a first DC voltage V1. The rectifier circuit 13 is also connected to a first conversion circuit 14, and outputs the rectified first DC voltage V1 to the first conversion circuit 14. In other words, the lighting device 1 further includes the rectifier circuit 13 that converts the AC voltage Vin supplied from an external source into the first DC voltage V1.

[0022] The rectifier circuit 13 is not limited to a full-wave rectifier circuit, but may be, for example, a half-wave rectifier circuit formed by one diode.

[0023] (2.1.4) First conversion circuit The first conversion circuit 14 is a conversion circuit that converts a first DC voltage V1 into a second DC voltage V2 that is different from the first DC voltage V1. More specifically, the first conversion circuit 14 includes a boost circuit 140 that boosts the first DC voltage V1 to a second DC voltage V2 that is higher than the first DC voltage V1. The boost circuit 140 is, for example, a boost chopper circuit.

[0024] (2.1.5) Second conversion circuit The second conversion circuit 15 is a conversion circuit that converts the second DC voltage V2 output from the first conversion circuit 14 into a third DC voltage V3 different from the second DC voltage V2. More specifically, the second conversion circuit 15 includes a step-down circuit 150 that steps down the second DC voltage V2 output from the first conversion circuit 14 to a third DC voltage V3 that is lower than the second DC voltage V2. The step-down circuit 150 is, for example, a step-down chopper circuit.

[0025] As shown in FIG. 2, the step-down circuit 150 includes a transformer Tr1. The transformer Tr1 includes a primary winding W1 and a secondary winding W2. The primary winding W1 includes a first winding W11 and a second winding W12 connected in series. The secondary winding W2 is magnetically coupled to the first winding W11 of the primary winding W1. As shown in FIG. 1, the secondary winding W2 supplies a fifth DC voltage V5 to the control circuit 17. That is, the fifth DC voltage V5 is a winding voltage output from the secondary winding W2.

[0026] (2.1.6) Power supply section As shown in FIG. 1, the power supply unit 16 includes a power supply circuit 161 and a comparison circuit 162.

[0027] The power supply circuit 161 generates a fourth DC voltage V4 based on the second DC voltage V2 output from the first conversion circuit .

[0028] The comparison circuit 162 compares the fourth DC voltage V4 output from the power supply circuit 161 with the fifth DC voltage V5 output from the second conversion circuit 15. More specifically, the comparison circuit 162 compares the voltage value of the fourth DC voltage V4 with the voltage value of the fifth DC voltage V5.

[0029] 1, the power supply unit 16 supplies an operating voltage Vm to the control circuit 17. More specifically, the power supply unit 16 supplies at least one of the fourth DC voltage V4 output from the power supply circuit 161 and the fifth DC voltage V5 output from the second conversion circuit 15 to the control circuit 17 as the operating voltage Vm. As described above, the fourth DC voltage V4 is a voltage generated by the power supply circuit 161 based on the second DC voltage V2 output from the first conversion circuit 14. In this embodiment, the power supply unit 16 supplies the fourth DC voltage V4 or the fifth DC voltage V5 to the control circuit 17 as the operating voltage Vm.

[0030] More specifically, when the comparison result of the comparator circuit 162 indicates that the voltage value of the fourth DC voltage V4 is higher than the voltage value of the fifth DC voltage V5, the power supply unit 16 supplies the fourth DC voltage V4 as the operating voltage Vm to the control circuit 17. Furthermore, when the comparison result of the comparator circuit 162 indicates that the voltage value of the fourth DC voltage V4 is lower than the voltage value of the fifth DC voltage V5, the power supply unit 16 supplies the fifth DC voltage V5 as the operating voltage Vm to the control circuit 17. In this case, the power supply circuit 161 stops outputting the fourth DC voltage V4 based on the second DC voltage V2.

[0031] (2.1.7) Control circuit The control circuit 17 is connected to each of the first conversion circuit 14 and the second conversion circuit 15. The control circuit 17 controls the first conversion circuit 14 and the second conversion circuit 15. More specifically, the control circuit 17 outputs a first control signal to the first conversion circuit 14, thereby controlling the on / off of a switching element included in the first conversion circuit 14 so that the second DC voltage V2 is output from the first conversion circuit 14. The control circuit 17 also outputs a second control signal to the second conversion circuit 15, thereby controlling the on / off of a switching element included in the second conversion circuit 15 so that the second conversion circuit 15 outputs a third DC voltage V3.

[0032] The control circuit 17 can be realized, for example, by a computer system having one or more processors and one or more memories. That is, the one or more processors execute a program recorded in one or more memories of the computer system, thereby functioning as the control circuit 17. Here, the program is pre-recorded in the memory of the computer system, but it may also 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.

[0033] (2.1.8) Adjustment circuit As shown in Fig. 2, the adjustment circuit 18 is connected to one end of the secondary winding W2 of the transformer Tr1. The adjustment circuit 18 adjusts the fifth DC voltage V5 so that the fifth DC voltage V5 is higher than the fourth DC voltage V4 during a third period T3 (see Fig. 3) described below. That is, the lighting device 1 further includes the adjustment circuit 18 that adjusts the fifth DC voltage V5 so that the fifth DC voltage V5 is higher than the fourth DC voltage V4.

[0034] As shown in FIG. 2, the adjustment circuit 18 includes a diode D1 and a resistor R1. The anode of the diode D1 is connected to one end of the secondary winding W2. The cathode of the diode D1 is connected to one end of the resistor R1. That is, the resistor R1 is connected in series with the diode D1. More specifically, the resistor R1 and the diode D1 are connected in series in this order from the secondary winding W2 side. In this way, the adjustment circuit 18 including the series circuit of the diode D1 and the resistor R1 is connected to one end of the secondary winding W2.

[0035] (2.2) Light source section The light source unit 2 is lit by a third DC voltage V3 supplied from the lighting device 1. The light source unit 2 has multiple (for example, two) boards and multiple light-emitting elements mounted on the surface of each board. Each board is formed in a long rectangular shape.

[0036] The plurality of light-emitting elements may include, for example, white LEDs for illumination with an incandescent color and white LEDs for illumination with a daylight color. The plurality of light-emitting elements are arranged so that LEDs of different colors are alternately aligned in a row along the longitudinal direction of each substrate. The plurality of light-emitting elements may be composed of only white LEDs for illumination with the same color, or may include white LEDs for illumination with three or more colors. The plurality of light-emitting elements may also include LEDs emitting light with colors other than white, such as red, green, and blue.

[0037] (3) Operation Next, the operation of the lighting device 1 according to the embodiment will be described with reference to Fig. 3. In Fig. 3, the horizontal axis represents time, and the vertical axis represents the AC voltage Vin, the fourth DC voltage V4, and the fifth DC voltage V5.

[0038] During a first period T1 (the period from time t1 to time t2) when the lighting device 1 is started up, the second DC voltage V2 output from the first conversion circuit 14 is supplied to the power supply unit 16. On the other hand, during the first period T1, the second conversion circuit 15 is not operating, and therefore the fifth DC voltage V5 is not supplied to the power supply unit 16. Therefore, during the first period T1, the power supply unit 16 supplies the fourth DC voltage V4 based on the second DC voltage V2 to the control circuit 17 because the voltage value of the fourth DC voltage V4 is higher than the voltage value of the fifth DC voltage V5 (see FIG. 3).

[0039] During a second period T2 (the period from time t3 to time t4) when the lighting device 1 is stopped, the second DC voltage V2 output from the first conversion circuit 14 is supplied to the power supply unit 16. Meanwhile, during the second period T2, the second conversion circuit 15 is stopped, and the fifth DC voltage V5 is no longer supplied to the power supply unit 16. Therefore, during the second period T2, the power supply unit 16 supplies the fourth DC voltage V4 based on the second DC voltage V2 to the control circuit 17 because the fourth DC voltage V4 is higher than the fifth DC voltage V5 (see FIG. 3). In this case, by supplying the second DC voltage V2 from the output side of the boost circuit 140 to the power supply unit 16, it is possible to supply a stable voltage (second DC voltage V2) to the power supply unit 16.

[0040] On the other hand, during a third period T3 (the period from time t2 to time t3) between the first period T1 and the second period T2, the second DC voltage V2 output from the first conversion circuit 14 is supplied to the power supply unit 16, and the fifth DC voltage V5 output from the second conversion circuit 15 is supplied to the power supply unit 16. Here, the fifth DC voltage V5 is made higher than the fourth DC voltage V4 by the above-mentioned adjustment circuit 18, and therefore the fifth DC voltage V5 output from the second conversion circuit 15 is supplied to the control circuit 17 (see FIG. 3). That is, during a third period T3 between the first period T1 when the lighting device 1 is started and the second period T2 when the lighting device 1 is stopped, the fourth DC voltage V4 is lower than the fifth DC voltage V5.

[0041] (4) Effects In the lighting device 1 according to the embodiment, at least one of the fourth DC voltage V4 generated in the power supply circuit 161 and the fifth DC voltage V5 output from the second conversion circuit 15 is supplied to the control circuit 17, thereby making it possible to reduce losses. In particular, in the present embodiment, the fourth DC voltage V4 or the fifth DC voltage V5 is supplied to the control circuit 17 depending on the comparison result of the comparison circuit 162, making it possible to more reliably reduce losses.

[0042] In the lighting device 1 according to the embodiment, the fifth DC voltage V5 is a winding voltage output from the secondary winding W2. In this case, since the operation of the power supply circuit 161 is stopped, it is possible to reduce the loss of the power supply unit 16.

[0043] In the lighting device 1 according to the embodiment, the adjustment circuit 18 can adjust the fifth DC voltage V5 so that the fifth DC voltage V5 is higher than the fourth DC voltage V4.

[0044] In the lighting device 1 according to the embodiment, the adjustment circuit 18 includes a diode D1 and a resistor R1 connected in series with the diode D1, and is capable of adjusting the fifth DC voltage V5 with a simple configuration.

[0045] In the lighting device 1 according to the embodiment, the rectifier circuit 13 can rectify the AC voltage Vin input from the outside into the first DC voltage V1.

[0046] The lighting fixture 10 according to the embodiment includes the lighting device 1 according to the embodiment, and therefore, it is possible to reduce losses.

[0047] (5) Variations 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 combinations.

[0048] (5.1) Variation 1 1 and 2, in the above-described embodiment, the fifth DC voltage V5 output from the second conversion circuit 15 is a winding voltage of the secondary winding W2 of the transformer Tr1. In contrast, as shown in FIG. 4, the fifth DC voltage V5 output from the second conversion circuit 15 may be the third DC voltage V3 output to the light source unit 2. That is, the fifth DC voltage V5 may be the third DC voltage V3 output from the step-down circuit 150.

[0049] In the lighting device 1 according to the first modification, the fourth DC voltage V4 or the fifth DC voltage V5 (third DC voltage V3) is also supplied to the control circuit 17, so that it is possible to reduce losses more reliably.

[0050] (5.2) Variation 2 In the above-described embodiment, the power supply unit 16 supplies the fourth DC voltage V4 or the fifth DC voltage V5 as the operating voltage Vm to the control circuit 17 in accordance with the comparison result between the fourth DC voltage V4 and the fifth DC voltage V5. In contrast, the power supply unit 16 may supply both the fourth DC voltage V4 and the fifth DC voltage V5 as the operating voltage Vm to the control circuit 17 regardless of the comparison result between the fourth DC voltage V4 and the fifth DC voltage V5.

[0051] (5.3) Variation 3 In the above-described embodiment, the first conversion circuit 14 is the boost circuit 140, and the second conversion circuit 15 is the step-down circuit 150.

[0052] Alternatively, the first conversion circuit 14 may be a step-down circuit, and the second conversion circuit 15 may be a step-up circuit. In this case, the second DC voltage V2 is lower than the first DC voltage V1, and the third DC voltage V3 is higher than the second DC voltage V2.

[0053] Furthermore, each of the first conversion circuit 14 and the second conversion circuit 15 may be a boost circuit. In this case, the second DC voltage V2 is higher than the first DC voltage V1, and the third DC voltage V3 is higher than the second DC voltage V2.

[0054] Furthermore, each of the first conversion circuit 14 and the second conversion circuit 15 may be a step-down circuit. In this case, the second DC voltage V2 is lower than the first DC voltage V1, and the third DC voltage V3 is lower than the second DC voltage V2.

[0055] (Aspect) The present specification discloses the following aspects.

[0056] A lighting device (1; 1A) according to a first aspect includes a first conversion circuit (14), a second conversion circuit (15), a control circuit (17), and a power supply unit (16). The first conversion circuit (14) converts a first DC voltage (V1) into a second DC voltage (V2) different from the first DC voltage (V1). The second conversion circuit (15) converts the second DC voltage (V2) output from the first conversion circuit (14) into a third DC voltage (V3) different from the second DC voltage (V2). The control circuit (17) controls the first conversion circuit (14) and the second conversion circuit (15). The power supply unit (16) supplies an operating voltage (Vm) to the control circuit (17). The power supply unit (16) includes a power supply circuit (161) that generates a fourth DC voltage (V4) based on the second DC voltage (V2) output from the first conversion circuit (14). The power supply unit (16) supplies at least one of a fourth DC voltage (V4) output from the power supply circuit (161) and a fifth DC voltage (V5) output from the second conversion circuit (15) to the control circuit (17) as an operating voltage (Vm).

[0057] According to this aspect, it is possible to reduce losses.

[0058] In the lighting device (1) according to the second aspect, in the first aspect, the first conversion circuit (14) includes a step-up circuit (140) that converts a first DC voltage (V1) into a second DC voltage (V2) that is higher than the first DC voltage (V1). The second conversion circuit (15) includes a step-down circuit (150) that converts the second DC voltage (V2) into a third DC voltage (V3) that is lower than the second DC voltage (V2). The step-down circuit (150) has a transformer (Tr1) that includes a primary winding (W1) and a secondary winding (W2). The fifth DC voltage (V5) is a winding voltage output from the secondary winding (W2).

[0059] According to this embodiment, it is possible to reduce the loss in the power supply unit (16).

[0060] In a lighting device (1A) according to the third aspect, in the first aspect, the first conversion circuit (14) includes a step-up circuit (140) that converts a first DC voltage (V1) into a second DC voltage (V2) that is higher than the first DC voltage (V1). The second conversion circuit (15) includes a step-down circuit (150) that converts the second DC voltage (V2) into a third DC voltage (V3) that is lower than the second DC voltage (V2). The fifth DC voltage (V5) is the third DC voltage (V3) output from the step-down circuit (150).

[0061] According to this embodiment, it is possible to reduce the loss in the power supply unit (16).

[0062] A lighting device (1;1A) according to a fourth aspect is any one of the first to third aspects, wherein the power supply unit (16) further includes a comparison circuit (162) that compares a fourth DC voltage (V4) with a fifth DC voltage (V5). When the comparison result of the comparison circuit (162) indicates that the fourth DC voltage (V4) is higher than the fifth DC voltage (V5), the power supply unit (16) supplies the fourth DC voltage (V4) to the control circuit (17). When the comparison result of the comparison circuit (162) indicates that the fourth DC voltage (V4) is lower than the fifth DC voltage (V5), the power supply unit (16) supplies the fifth DC voltage (V5) to the control circuit (17).

[0063] According to this aspect, it is possible to more reliably reduce losses.

[0064] In the lighting device (1;1A) according to the fifth aspect, in the fourth aspect, during the third period (T3) between the first period (T1) when the lighting device (1;1A) is started and the second period (T2) when the lighting device (1;1A) is stopped, the fourth DC voltage (V4) is lower than the fifth DC voltage (V5).

[0065] According to this embodiment, it is possible to reduce the loss of the power supply unit (16) in the third period (T3).

[0066] The lighting device (1; 1A) according to a sixth aspect is the lighting device (1) according to the fourth or fifth aspect, further including an adjustment circuit (18). The adjustment circuit (18) adjusts the fifth DC voltage (V5) so that the fifth DC voltage (V5) is higher than the fourth DC voltage (V4).

[0067] According to this aspect, it is possible to adjust the fifth DC voltage (V5) so that the fifth DC voltage (V5) is higher than the fourth DC voltage (V4).

[0068] A lighting device (1;1A) according to a seventh aspect is the sixth aspect, wherein the adjustment circuit (18) includes a diode (D1) and a resistor (R1). The resistor (R1) is connected in series with the diode (D1).

[0069] According to this aspect, it is possible to adjust the fifth DC voltage (V5) with a simple configuration.

[0070] A lighting device (1; 1A) according to an eighth aspect is any one of the first to seventh aspects, and further includes a rectifier circuit (13). The rectifier circuit (13) converts an AC voltage (Vin) supplied from outside into a first DC voltage (V1).

[0071] According to this aspect, it is possible to rectify the AC voltage (Vin) supplied from the outside into the first DC voltage (V1).

[0072] A lighting fixture (10) according to a ninth aspect includes the lighting device (1; 1A) according to any one of the first to eighth aspects and a light source unit (2). The light source unit (2) is turned on by a third DC voltage (V3) supplied from the lighting device (1; 1A).

[0073] According to this aspect, it is possible to reduce the loss in the lighting device (1; 1A).

[0074] The configurations according to the second to eighth aspects are not essential for the lighting device (1; 1A) and can be omitted as appropriate. [Explanation of symbols]

[0075] 1.1A lighting device 2 Light source section 13 Rectifier circuit 14 First conversion circuit 15 Second conversion circuit 16 Power supply section 17 Control circuit 18 Adjustment circuit 140 Boost circuit 150 Step-down circuit 161 Power supply circuit 162 Comparison circuit D1 Diode R1 resistor T1 1st period T2 2nd period T3 Third Period Tr1 transformer V1 First DC voltage V2 Second DC voltage V3 Third DC voltage V4 Fourth DC voltage V5 Fifth DC voltage Vin AC voltage Vm Operating voltage W1 Primary winding W2 Secondary winding

Claims

1. a first conversion circuit that converts a first DC voltage into a second DC voltage different from the first DC voltage; a second conversion circuit that converts the second DC voltage output from the first conversion circuit into a third DC voltage different from the second DC voltage; a control circuit for controlling the first conversion circuit and the second conversion circuit; a power supply unit that supplies an operating voltage to the control circuit; The power supply unit a power supply circuit that generates a fourth DC voltage based on the second DC voltage output from the first conversion circuit; At least one of the fourth DC voltage output from the power supply circuit and the fifth DC voltage output from the second conversion circuit is supplied to the control circuit as the operating voltage. Lighting device.

2. the first conversion circuit includes a boost circuit that converts the first DC voltage into the second DC voltage that is higher than the first DC voltage; the second conversion circuit includes a step-down circuit that converts the second DC voltage into the third DC voltage that is lower than the second DC voltage; the step-down circuit has a transformer including a primary winding and a secondary winding; the fifth DC voltage is a winding voltage output from the secondary winding; The lighting device according to claim 1 .

3. the first conversion circuit includes a boost circuit that converts the first DC voltage into the second DC voltage that is higher than the first DC voltage; the second conversion circuit includes a step-down circuit that converts the second DC voltage into the third DC voltage that is lower than the second DC voltage; the fifth DC voltage is the third DC voltage output from the voltage step-down circuit; The lighting device according to claim 1 .

4. the power supply unit further includes a comparison circuit that compares the fourth DC voltage with the fifth DC voltage, The power supply unit supplying the fourth DC voltage to the control circuit when the comparison result of the comparator circuit indicates that the fourth DC voltage is higher than the fifth DC voltage; supplying the fifth DC voltage to the control circuit when the comparison result of the comparator circuit indicates that the fourth DC voltage is lower than the fifth DC voltage; The lighting device according to any one of claims 1 to 3.

5. In a third period between a first period when the lighting device is started and a second period when the lighting device is stopped, the fourth DC voltage is lower than the fifth DC voltage. The lighting device according to claim 4.

6. further comprising an adjustment circuit that adjusts the fifth DC voltage so that the fifth DC voltage is higher than the fourth DC voltage; The lighting device according to claim 4.

7. The adjustment circuit A diode and a resistor connected in series with the diode; The lighting device according to claim 6.

8. further comprising a rectifier circuit that converts an AC voltage supplied from an external source into the first DC voltage; The lighting device according to any one of claims 1 to 3.

9. The lighting device according to any one of claims 1 to 3, a light source unit that is lit by the third DC voltage supplied from the lighting device, Lighting fixtures.

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