Power supply unit and lighting unit

Abstract

To provide a power supply capable of setting a rated current of a light source regardless of a resistance value of a rated current setting resistor.SOLUTION: A power supply 12 includes a conversion circuit 21, a detection circuit 30, and a control unit 22. The conversion circuit 21 is connected to a light source unit 11 having a light source 15 and a rated current setting resistor 16 for setting a rated current of the light source 15, and is configured to convert input power into lighting power for lighting the light source 15 to be supplied to the light source 15. The detection circuit 30 can supply a current for detection to the rated current setting resistor 16 and can change a current value of the current for detection to be supplied, and detects a detected voltage in accordance with a resistance value of the rated current setting resistor 16. The control unit 22 sets the rated current of the light source 15 in accordance with the detected voltage detected by the detection circuit 30 and controls the conversion circuit 21 so that a current of the lighting power becomes the rated current.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a power supply device and a lighting device.

Background Art

[0002] Conventionally, in a power supply device to which a light source unit having a light source is connected and which supplies a lighting current corresponding to the rated current of the light source, there is a power supply device capable of accommodating different types of light source units having different rated currents of the light source. In this case, the light source unit includes a rated current setting resistor for setting the rated current of this light source together with the light source. Further, the power supply device passes a current through the rated current setting resistor, detects a detection voltage corresponding to the resistance value of the rated current setting resistor, and sets the rated current of the light source according to the detection voltage.

[0003] The power supply device can only accommodate a light source unit having a rated current setting resistor within a corresponding range of resistance values, and cannot accommodate a light source unit having a rated current setting resistor within a different range of resistance values. Therefore, it is desirable to be able to set the rated current of the light source regardless of the resistance value of the rated current setting resistor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide a power supply device and a lighting device capable of setting the rated current of a light source regardless of the resistance value of a rated current setting resistor.

Means for Solving the Problems

[0006] The power supply device according to the embodiment includes a conversion circuit, a detection circuit, and a control unit , switching circuit and and. The conversion circuit is a light source andResistor for setting the rated current of the light source. A light source circuit in which two are connected in series. A light source unit is connected, and the input power is converted into lighting power that illuminates the light source and supplied to the light source. The detection circuit supplies a detection current to a rated current setting resistor and can change the value of the supplied detection current, detecting a detection voltage corresponding to the resistance value of the rated current setting resistor. The control unit sets the rated current of the light source according to the detection voltage detected by the detection circuit and controls the conversion circuit so that the lighting power current becomes the rated current. The switching circuit connects the rated current setting resistor of the light source circuit to the detection circuit when setting the rated current of the light source, and bypasses the rated current setting resistor of the light source circuit that is connected to the conversion circuit after the rated current of the light source has been set. [Effects of the Invention]

[0007] According to the power supply device of this embodiment, it is expected that the rated current of the light source can be set regardless of the resistance value of the resistor for setting the rated current. [Brief explanation of the drawing]

[0008] [Figure 1] This is a circuit diagram of a lighting device showing the detection path of the first embodiment. [Figure 2] This is a circuit diagram of the lighting device showing the first lighting path. [Figure 3] This is a circuit diagram of the lighting device showing the second lighting path. [Figure 4] This is a flowchart showing the operation of the same lighting device. [Figure 5] This is a circuit diagram of a lighting device showing a second embodiment. [Figure 6] This is a circuit diagram of a lighting device showing a third embodiment. [Modes for carrying out the invention]

[0009] The first embodiment will be described below with reference to Figures 1 to 4.

[0010] As shown in Figures 1 to 3, the lighting device 10 comprises a light source unit 11 and a power supply unit 12 to which the light source unit 11 is connected. The lighting device 10 may be, for example, a base light, a downlight, or other lighting equipment installed on the ceiling.

[0011] The light source unit 11 includes a light source 15 and a rated current setting resistor 16 for setting the rated current of the light source 15. The light source 15 and the rated current setting resistor 16 are connected in series, forming a series circuit light source circuit 17.

[0012] The light source 15 uses, for example, an LED or other light-emitting element. The light source 15 uses one or more light-emitting elements, and if multiple light-emitting elements are used, they are connected in series or in series-parallel. The light source 15 has different rated currents suitable for lighting depending on the type of light-emitting element, such as its brightness and color.

[0013] The resistance value of the rated current setting resistor 16 is pre-associated with the rated current value of the light source 15, and the resistance value of the rated current setting resistor 16 is changed in accordance with the difference in the rated current value of the light source 15.

[0014] The resistance value of the resistor 16 for setting the rated current is generally set to a first resistance value range, which is a low resistance value range of several ohms, and the resistance value is changed within this first resistance value range to correspond to the difference in the rated current of the light source 15.

[0015] Furthermore, the resistance value of the rated current setting resistor 16 is set to a second resistance value range, which is higher than the first resistance value range, separate from the first resistance value range. In some cases, the resistance value is changed within this second resistance value range to correspond to differences in the rated current of the light source 15.

[0016] Therefore, the rated current setting resistor 16 has at least two resistance ranges: a first resistance range with low resistance values ​​and a second resistance range with high resistance values, and is set to one of these for each light source unit 11. In addition to the first and second resistance ranges, the rated current setting resistor 16 may have two or more resistance ranges, such as a third resistance range and a fourth resistance range, which have resistance values ​​even higher than the second resistance range.

[0017] The light source unit 11 has a first light source terminal 18a connected to the anode side of the light emitting element, which is the high potential side of the light source circuit 17, a second light source terminal 18b connected to the low potential side of the light source circuit 17, and a third light source terminal 18c connected to the connection point between the cathode side of the light emitting element, which is the low potential side of the light source 15, and the rated current setting resistor 16, and is electrically connected to the power supply device 12 through these light source terminals 18a, 18b, and 18c. The light source terminals 18a, 18b, and 18c may be constituted by, for example, a connector electrically connected to the power supply device 12.

[0018] The light source unit 11 may have a structure that can be attached to and detached from and replaced with the lighting device 10, or may have an integral structure that cannot be attached to and detached from and replaced with.

[0019] Further, the power supply device 12 is capable of corresponding to a plurality of types of light source units 11 having light sources 15 with different rated currents. The power supply device 12 includes a conversion circuit 21 that converts input power into lighting power for lighting the light source 15 and supplies it to the light source unit 11, and a control unit 22 that controls this conversion circuit 21.

[0020] The conversion circuit 21 includes an AC / DC circuit 23, which is a first conversion circuit, and a DC / DC circuit 24, which is a second conversion circuit.

[0021] The AC / DC circuit 23 converts the AC voltage supplied from the AC power supply 25 into a DC voltage and supplies it to the DC / DC circuit 24. The AC / DC circuit 23 includes a rectification circuit that rectifies the AC voltage supplied from the AC power supply 25 into a DC voltage, and may further include a power factor correction circuit, which is a boost chopper circuit that boosts the DC voltage rectified by the rectification circuit.

[0022] The DC / DC circuit 24 converts the DC power supplied from the AC / DC circuit 23 into DC lighting power that illuminates the light source 15, and supplies it to the light source 15. The DC / DC circuit 24 is composed of a constant current circuit equipped with a step-down chopper circuit that steps down the DC voltage boosted by the AC / DC circuit 23. The control unit 22 controls the switching of the switching elements in this constant current circuit (step-down chopper circuit), thereby supplying a constant lighting current to the light source 15 according to the rated current of the light source 15.

[0023] The power supply unit 12 has a first power supply terminal 26a connected to the high-potential output section of the DC / DC circuit 24's ignition power, a second power supply terminal 26b connected to the low-potential output section of the DC / DC circuit 24's ignition power, and a third power supply terminal 26c connected to the output section of the DC / DC circuit 24 (detection circuit 30) that outputs the detection current. These power supply terminals 26a, 26b, and 26c are electrically connected to the light source terminals 18a, 18b, and 18c of the light source unit 11. The power supply terminals 26a, 26b, and 26c may be configured as, for example, connectors that are electrically connected to the light source terminals 18a, 18b, and 18c of the light source unit 11.

[0024] Furthermore, the DC / DC circuit 24 includes a detection circuit 30 that supplies a detection current to the rated current setting resistor 16 of the light source unit 11 and detects a detection voltage corresponding to the resistance value of the rated current setting resistor 16. Note that the detection circuit 30 may be provided separately from the DC / DC circuit 24 and the conversion circuit 21.

[0025] The detection circuit 30 generates a detection current using the DC power supplied to the DC / DC circuit 24, and flows the generated detection current through detection path A, which passes through the third power terminal 26c, the third light source terminal 18c, the rated current setting resistor 16, the second light source terminal 18b, and the second power terminal 26b. The detection circuit 30 detects the voltage generated according to the resistance value of the rated current setting resistor 16 as the detection voltage and outputs it to the control unit 22.

[0026] The detection current generated by the detection circuit 30 has two values: a first current value, which is a large current value (larger than the second current value) that enables detection of the detection voltage when the rated current setting resistor 16 is in a first resistance range, which is a low resistance range; and a second current value, which is a smaller current value than the first current value that enables detection of the detection voltage when the rated current setting resistor 16 is in a second resistance range, which is a high resistance range. The detection circuit 30 is switchable between at least two current values. Furthermore, if the resistance range of the rated current setting resistor 16 corresponds to two or more resistance ranges in addition to the first and second resistance ranges, such as a third resistance range and a fourth resistance range, the detection circuit 30 is switchable between two or more current values.

[0027] The value of the detection current supplied from the detection circuit 30 may be switched in steps from a small value to a large value, or from a large value to a small value, or it may be changed continuously.

[0028] Furthermore, the control unit 22 determines the value of the rated current of the light source 15 from the value of the detection current flowing from the detection circuit 30 (first current value or second current value) and the value of the detection voltage detected by the detection circuit 30. If the value is determined, it sets it as the rated current of the light source 15 and controls the conversion circuit 21 so that the current supplied to the light source 15 for lighting power becomes the set rated current, that is, it controls the switching of the switching element of the DC / DC circuit 24.

[0029] The value of the detection voltage detected by the detection circuit 30 and the value of the rated current of the light source 15 are pre-associated. Based on this association, the control unit 22 identifies the value of the rated current of the light source 15 from the value of the detection voltage detected by the detection circuit 30, and sets the identified value of the rated current as the rated current of the light source 15 of the light source unit 11 connected to the power supply unit 12.

[0030] The control unit 22 includes thresholds for determining the rated current value of the light source 15 from the detected voltage value detected by the detection circuit 30. In this case, there is a first detection voltage threshold that determines the detected voltage obtained when a detection current of a large first current value is passed from the detection circuit 30 through the rated current setting resistor 16 in a first resistance range with low resistance values, and a second detection voltage threshold that determines the detected voltage obtained when a detection current of a small second current value is passed from the detection circuit 30 through the rated current setting resistor 16 in a second resistance range with high resistance values, and so on, with at least two detection voltage thresholds. Note that if the resistance range of the rated current setting resistor 16 has two or more resistance ranges in addition to the first and second resistance ranges, such as a third resistance range and a fourth resistance range, the control unit 22 may include two or more detection voltage thresholds in addition to the first and second detection voltage thresholds.

[0031] The control unit 22 does not determine the rated current because the detection voltage obtained when a detection current of a large first current value is passed from the detection circuit 30 through the rated current setting resistor 16 in a high resistance range, or when a detection current of a small second current value is passed from the detection circuit 30 through the rated current setting resistor 16 in a low resistance range, is outside the first and second detection voltage thresholds.

[0032] Alternatively, the control unit 22 may determine the rated current by comparing the detected voltage detected by the detection circuit 30 with a sequentially changing reference voltage using a comparator.

[0033] The control unit 22 may be composed of a single integrated circuit on a single chip, or it may be composed of a combination of multiple integrated circuits.

[0034] Furthermore, the power supply unit 12 includes a switching circuit 33 that switches the lighting path through which the lighting power flows to the light source unit 11. The switching circuit 33 may be included in the DC / DC circuit 24, or it may be provided separately from the DC / DC circuit 24.

[0035] The switching circuit 33 includes a switching element 34 connected in parallel with the rated current setting resistor 16 between the second power supply terminal 26b and the third power supply terminal 26c. The switching element 34 is, for example, an n-channel type MOSFET, with its drain connected to the third power supply terminal 26c, its source connected to the second power supply terminal 26b, and its gate connected to the control unit 22, which switches it on and off.

[0036] When the rated current of the light source 15 is set (detected), the switching circuit 33 turns off the switching element 34, as shown in Figure 1, thereby forming a detection path A that connects the detection circuit 30 and the rated current setting resistor 16.

[0037] When the light source 15 is lit, the switching circuit 33 turns off the switching element 34 as shown in Figure 2, thereby forming a first lighting path B1 that passes through the first power terminal 26a, the first light source terminal 18a, the light source 15, the rated current setting resistor 16, the second light source terminal 18b, and the second power terminal 26b. Also, as shown in Figure 3, by turning on the switching element 34, a second lighting path B2 is formed that passes through the first power terminal 26a, the first light source terminal 18a, the light source 15, the third light source terminal 18c, the third power terminal 26c, and the switching element 34, allowing switching between the first lighting path B1 and the second lighting path B2. The second lighting path B2 is a path that bypasses the rated current setting resistor 16 of the light source circuit 17 connected to the conversion circuit 21.

[0038] Next, the operation of the power supply unit 12 will be explained with reference to the flowchart in Figure 4.

[0039] The resistance value of the resistor 16 for setting the rated current of the light source unit 11 connected to the power supply unit 12 can be either a first resistance value range, which is a range of low resistance values, or a second resistance value range, which is a range of high resistance values.

[0040] When power is supplied from the AC power supply 25 to the power supply unit 12 and the control unit 22 is started up, the control unit 22 performs an operation to determine the rated current of the light source 15 from the resistance value of the rated current setting resistor 16 of the light source unit 11 before supplying lighting power to the light source 15 from the DC / DC circuit 24.

[0041] The detection circuit 30 generates a detection current, and as shown in Figure 1, it flows the generated detection current through the detection path A, which passes through the third power supply terminal 26c, the third light source terminal 18c, the rated current setting resistor 16, the second light source terminal 18b, and the second power supply terminal 26b. The voltage generated according to the resistance value of the rated current setting resistor 16 is detected as the detection voltage and output to the control unit 22.

[0042] At this time, the detection circuit 30 sends a detection current of a second current value, which is a small current value, to the detection path A (step S1), and detects a detection voltage corresponding to the resistance value of the rated current setting resistor 16.

[0043] Next, the control unit 22 determines the value of the rated current of the light source 15 from the value of the detected voltage detected by the detection circuit 30, based on the correspondence between the value of the detected voltage detected by the detection circuit 30 and the value of the rated current of the light source 15. For example, since a detection current of the second current value is flowing here, the control unit 22 determines the value of the rated current of the light source 15 from the value of the detected voltage detected by the detection circuit 30 by comparing the value of the detected voltage detected by the detection circuit 30 with a second detection voltage threshold that determines the detected voltage obtained when the detection current of the second current value flows from the detection circuit 30 to the rated current setting resistor 16 in the second resistance value range.

[0044] If the value of the detected voltage detected by the detection circuit 30 is within the range of the second detection voltage threshold (YES in step S2), the control unit 22 determines the value of the rated current from the value of the detected voltage and the second detection voltage threshold (step S3), and sets it as the rated current of the light source 15 of the light source unit 11 connected to the power supply unit 12.

[0045] When the control unit 22 determines the value of the rated current of the light source 15 by sending a detection current for the second current value from the detection circuit 30 to the rated current setting resistor 16, it determines that the rated current setting resistor 16 is in the second resistance value range with a higher resistance value and turns on the switching element 34 of the switching circuit 33. In this case, as shown in Figure 3, a second lighting path B2 is formed passing through the first power terminal 26a, the first light source terminal 18a, the light source 15, the third light source terminal 18c, the third power terminal 26c, and the switching element 34, thus switching to a bypass path that bypasses the rated current setting resistor 16 (step S4).

[0046] The control unit 22 sets the rated current of the light source 15, then controls the DC / DC circuit 24 to supply lighting power from the DC / DC circuit 24 to the light source 15 (step S5), and controls the current of that lighting power to be equal to the rated current. As a result, the light source 15 lights up when supplied with lighting power equal to the rated current.

[0047] At this time, since the switching circuit 33 forms a second lighting path B2, the lighting power from the DC / DC circuit 24 is passed through the second lighting path B2, bypassing the high-resistance rated current setting resistor 16, thereby eliminating power loss in the rated current setting resistor 16.

[0048] On the other hand, if the detected voltage detected when the second detection current is applied exceeds the range of the second detection voltage threshold (a value that is too large or too small) (NO in step S2), it is determined whether the detected voltage is higher than the second detection voltage threshold (step S6). If the detected voltage is higher than the second detection voltage threshold (YES in step S6), it is determined that an unsuitable light source 15 is installed or that the light source 15 is not installed (step S7), and power is not supplied from the DC / DC circuit 24 (step S8).

[0049] Furthermore, if the detected voltage detected when the second detection current is applied is smaller than the range of the second detection voltage threshold (NO in step S6), the detection circuit 30 switches the detection current to the first detection current value and flows the detection current of the first detection current value through the detection path A (step S9), and detects the detection voltage corresponding to the resistance value of the rated current setting resistor 16.

[0050] Next, the control unit 22 determines the value of the rated current of the light source 15 from the value of the detected voltage detected by the detection circuit 30, based on the correspondence between the value of the detected voltage detected by the detection circuit 30 and the value of the rated current of the light source 15. For example, since a detection current of a first current value is flowing here, the control unit 22 determines the value of the rated current of the light source 15 from the value of the detected voltage detected by the detection circuit 30 by comparing the value of the detected voltage detected by the detection circuit 30 with a first detection voltage threshold that determines the detected voltage obtained when the detection current of the first current value flows from the detection circuit 30 to the rated current setting resistor 16 in a first resistance value range.

[0051] If the value of the detected voltage detected by the detection circuit 30 is within the range of the first detection voltage threshold (YES in step S10), the control unit 22 determines the value of the rated current from the value of the detected voltage and the first detection voltage threshold (step S11), and sets it as the rated current of the light source 15 of the light source unit 11 connected to the power supply unit 12.

[0052] The control unit 22 sets the rated current of the light source 15, then controls the DC / DC circuit 24 to supply lighting power from the DC / DC circuit 24 to the light source 15 (step S12), and controls the current of that lighting power to be equal to the rated current. As a result, the light source 15 lights up when supplied with lighting power equal to the rated current.

[0053] When the control unit 22 determines the value of the rated current of the light source 15 by sending a detection current for the first current value from the detection circuit 30 to the rated current setting resistor 16, it may determine that the rated current setting resistor 16 is in a first resistance value range with a low resistance value and turn off the switching element 34 of the switching circuit 33. In this case, as shown in Figure 2, a first lighting path B1 is formed passing through the first power supply terminal 26a, the first light source terminal 18a, the light source 15, the rated current setting resistor 16, the second light source terminal 18b, and the second power supply terminal 26b, and lighting power from the DC / DC circuit 24 flows through the first lighting path B1, lighting the light source 15. In this first lighting path B1, the lighting current flows through the rated current setting resistor 16, but because the resistance value of the rated current setting resistor 16 is low, the effect of power loss is small.

[0054] However, as shown in Figure 3, by turning on the switching element 34 of the switching circuit 33, a second lighting path B2 is formed that passes through the first power supply terminal 26a, the first light source terminal 18a, the light source 15, the third light source terminal 18c, the third power supply terminal 26c, and the switching element 34. The lighting power from the DC / DC circuit 24 is then passed through the second lighting path B2, bypassing the rated current setting resistor 16 and eliminating power loss in the rated current setting resistor 16.

[0055] On the other hand, if the detection circuit 30 sends a current for detecting the first current value to the detection path A, but the value of the rated current of the light source 15 cannot be determined from the value of the detected voltage detected by the detection circuit 30 (NO in step S10), it is determined that an unsuitable light source 15 is installed or that the light source 15 is not installed (step S7), and power is not supplied from the DC / DC circuit 24 (step S8).

[0056] However, if the resistance value of the rated current setting resistor 16 is in the low first resistance value range, the detection voltage corresponding to the resistance value of the rated current setting resistor 16 may vary due to the contact resistance of the connector connecting the light source unit 11 and the power supply unit 12, and the resistance of the wires, and the rated current of the light source 15 set from the detection voltage may deviate from the actual rated current of the light source 15. Also, if a detection current with a small current value is passed through the rated current setting resistor 16 with a low resistance value, the detected voltage may be small and may not be detected correctly.

[0057] Therefore, by setting the resistance value of the rated current setting resistor 16 to a higher second resistance value range, the effects described above can be mitigated. However, in a power supply unit 12 where the detection current supplied from the detection circuit 30 is set to a second current value corresponding to the rated current setting resistor 16 in the second resistance value range, compatibility with the light source unit 11 equipped with a rated current setting resistor 16 in a lower first resistance value range is lost. Furthermore, if a large detection current is passed through a rated current setting resistor 16 with a high resistance value, the rated power of the rated current setting resistor 16 may be exceeded, potentially causing the rated current setting resistor 16 to be damaged due to overheating.

[0058] In the power supply unit 12 of this embodiment, it is possible to change the value of the detection current supplied from the detection circuit 30 to the rated current setting resistor 16, that is, to switch between a first current value and a second current value, so that the rated current of the light source 15 can be set regardless of the resistance value of the rated current setting resistor 16.

[0059] Furthermore, by increasing the resistance value of the rated current setting resistor 16, the influence of contact resistance of the connector connecting the light source unit 11 and the power supply unit 12, as well as the resistance of the wires, can be reduced. Moreover, even if the resistance value of the rated current setting resistor 16 is increased, the switching circuit 33 bypasses the rated current setting resistor 16 with the higher resistance value, preventing the lighting power from flowing through the rated current setting resistor 16 and thus preventing power loss in the rated current setting resistor 16.

[0060] Alternatively, the detection current for the first current value and the detection current for the second current value may be sequentially passed through detection path A, and the rated current of the light source 15 may be identified and set from all the detected voltages obtained.

[0061] Next, Figure 5 shows a second embodiment.

[0062] The detection path A, through which the detection current flows from the detection circuit 30, is a path that passes through the third power terminal 26c, the third light source terminal 18c, the rated current setting resistor 16, the second light source terminal 18b, and the second power terminal 26b, and is a path that connects both ends of the rated current setting resistor 16 to the detection circuit 30.

[0063] The lighting path B, through which the lighting current flows from the DC / DC circuit 24, is a path that passes through the first power terminal 26a, the first light source terminal 18a, the light source 15, the second light source terminal 18b, and the second power terminal 26b, and is a path that connects both ends of the light source 15 to the DC / DC circuit 24.

[0064] In detection path A, a reverse current prevention circuit 37 is provided between the detection circuit 30 and the third power supply terminal 26c to prevent the lighting power from flowing through the rated current setting resistor 16. The reverse current prevention circuit 37 uses a diode 38 whose cathode is connected to the third power supply terminal 26c and whose anode is connected to the detection circuit 30.

[0065] Furthermore, in the second embodiment, the lighting power flowing through the lighting path B does not flow through the rated current setting resistor 16, thus preventing power loss in the rated current setting resistor 16.

[0066] The reverse current prevention circuit 37 may also be a switch that is turned on or off by the control unit 22.

[0067] Next, Figure 6 shows a third embodiment.

[0068] The light source unit 11 is provided with a light source 15 and a rated current setting resistor 16 independently. The light source unit 11 includes a first light source terminal 18a and a second light source terminal 18b connected to both ends of the light source 15, and a third light source terminal 18c and a fourth light source terminal 18d connected to both ends of the rated current setting resistor 16.

[0069] The power supply unit 12 includes a first power terminal 26a and a second power terminal 26b connected to the output section of the lighting power of the DC / DC circuit 24, and a third power terminal 26c and a fourth power terminal 26d connected to the output section of the detection current of the detection circuit 30.

[0070] The detection path A, through which the detection current flows from the detection circuit 30, is a path that passes through the third power terminal 26c, the third light source terminal 18c, the rated current setting resistor 16, the fourth light source terminal 18d, and the fourth power terminal 26d.

[0071] The lighting path B, through which the lighting current flows from the DC / DC circuit 24, is a path that passes through the first power terminal 26a, the first light source terminal 18a, the light source 15, the second light source terminal 18b, and the second power terminal 26b.

[0072] Furthermore, in the third embodiment, since the detection path A and the lighting path B are provided independently, lighting power does not flow to the rated current setting resistor 16, thus preventing power loss in the rated current setting resistor 16.

[0073] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0074] 10 Lighting devices 11 Light source section 12 Power supply 15 light source 16 Rated current setting resistor 17 Light source circuit 21 Conversion Circuit 22 Control Unit 30 Detection Circuit 33 Switching circuit A Detection path B Lighting path

Claims

1. A light source unit is connected, which has a light source circuit in which a light source and a rated current setting resistor for setting the rated current of the light source are connected in series; and a conversion circuit is connected that converts the input power into lighting power that illuminates the light source and supplies it to the light source; A detection circuit that supplies a detection current to the rated current setting resistor and can change the value of the supplied detection current, and detects a detection voltage corresponding to the resistance value of the rated current setting resistor; A control unit sets the rated current of the light source according to the detected voltage detected by the detection circuit and controls the conversion circuit so that the current of the lighting power becomes the rated current; A switching circuit that connects the rated current setting resistor of the light source circuit to the detection circuit when setting the rated current of the light source, and bypasses the rated current setting resistor of the light source circuit which is connected to the conversion circuit after the rated current of the light source has been set; A power supply device characterized by having the following features.

2. A light source unit having a light source circuit in which a light source and a rated current setting resistor for setting the rated current of the light source are connected in series; The power supply unit to which the aforementioned light source unit is connected; Equipped with, The aforementioned power supply device The aforementioned light source unit is connected to a conversion circuit that converts the input power into lighting power for the light source and supplies it to the light source, A detection circuit that supplies a detection current to the rated current setting resistor and can change the current value of the supplied detection current, and detects a detection voltage corresponding to the resistance value of the rated current setting resistor, A control unit sets the rated current of the light source according to the detection voltage detected by the detection circuit and controls the conversion circuit so that the current of the lighting power becomes the rated current. A switching circuit that connects the rated current setting resistor of the light source circuit to the detection circuit when setting the rated current of the light source, and bypasses the rated current setting resistor of the light source circuit which is connected to the conversion circuit after the rated current of the light source has been set, A lighting device characterized by having the following features.

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