Lighting devices and lighting devices

Abstract

This helps to shorten the time it takes for the amount of DC power supplied to a light source module to reach the amount of current corresponding to the amount of power for desired brightness from the start of supply. [Solution] The lighting device 12 includes a full-wave rectifier circuit 13 that rectifies the AC voltage of the AC power supplied from an external power source 100 into a DC voltage, an electrolytic capacitor 157 that smooths the rectified DC voltage, a supply circuit 16 that adjusts the amount of current of the DC power supplied from the electrolytic capacitor 157 and supplies it to the light source module 11, a ripple detection unit 183 that detects the ripple width of the DC voltage smoothed by the electrolytic capacitor 157, a difference detection unit 184 that detects the difference between the detected value of the ripple width and a threshold value, and a setting unit 19 that sets the increase in the current amount per unit time when adjusting the amount of current of the DC power supplied to the light source module 11 to a rated current amount to a larger increase the larger the difference detected by the difference detection unit 184.

Description

[Technical Field]

[0001] The present disclosure relates to a lighting device having an electrolytic capacitor that smooths ripple voltage, and to an illumination device having the lighting device. [Background technology]

[0002] In conventional lighting devices, electrolytic capacitors are provided to smooth the DC voltage containing ripple components rectified from the AC voltage by a rectifier circuit. The capacitance of electrolytic capacitors decreases at low temperatures, for example, temperatures lower than room temperature. This reduces their ability to smooth the DC voltage containing ripple components, resulting in an increase in the ripple components. When the ripple components increase, there is a risk of short-circuiting the electrolytic capacitor itself or of reverse current being generated in the switching elements around the electrolytic capacitor, causing the switching elements to fail. Therefore, when the ripple components are large, it is desirable to reduce the power supplied to the light source module (the load) to suppress the voltage applied to the electrolytic capacitor. For example, Patent Document 1 discloses a power conversion device that reduces the power supplied to a light source load when the ripple component is large. This power conversion device detects the DC voltage across an electrolytic capacitor that smooths the rectified DC voltage. If the maximum or minimum value of the detected DC voltage is far from the allowable maximum or minimum threshold, the power supplied to the load is increased at a constant rate without limiting the increase. However, if the maximum or minimum value across the electrolytic capacitor is close to the allowable maximum or minimum threshold, the power supply is limited by prohibiting an increase in the power supplied to the load, reducing the power supplied to the load, or stopping the power supply to the load. This power limiting operation suppresses the operation of the load when the ripple component is large, preventing the load from continuing to operate in an unstable state with the supplied power with a large ripple component. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6758493 Summary of the Invention [Problem to be solved by the invention]

[0004] The power conversion device of Patent Document 1 limits the current supplied to the load when the detected maximum or minimum value of the DC voltage is close to the threshold of the maximum or minimum allowable value, thereby preventing the load from continuing to operate in an unstable state with the supplied power while the ripple component of the DC voltage remains large. On the other hand, when the detected maximum or minimum value of the DC voltage is far from the threshold of the maximum or minimum allowable value, i.e., when the ripple component of the DC voltage is within the allowable range, the power supplied to the load is increased at a constant rate of increase. Therefore, even if the ripple component of the DC voltage is small and does not affect the stable operation of the load, it takes a time corresponding to the constant rate of increase for the current supplied to the load to reach the desired current. A lighting device obtains the brightness desired by a user by adjusting the amount of power supplied to a light source module, which is a load, and the amount of power supplied is adjusted by controlling the amount of DC power supplied to the light source module. Since it is desirable for a lighting device to take as short a time as possible from when a user issues a turn-on command until the brightness desired by the user is achieved, it is desirable that the time from when the lighting operation begins after the turn-on command until the amount of DC power supplied to the light source module reaches the rated current amount corresponding to the amount of power for the desired brightness be as short as possible. When a power conversion device such as that disclosed in Patent Document 1 is applied as a lighting device for such a lighting device, as described above, in a state in which the ripple component of the detected DC voltage does not affect the stable operation of the load, the amount of current of DC power supplied to the light source module increases at a constant rate from the start of supply until it reaches the rated current amount. Even in a state in which the stable operation of the lighting device is not affected, there is a problem in that it is necessary to wait a certain amount of time until the amount of current of DC power supplied to the light source module reaches the rated current amount corresponding to the power amount for the desired brightness.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a lighting device that can shorten the time it takes for the amount of DC power supplied to a light source module from the start of supply to reach the amount of current corresponding to the amount of power for the desired brightness, when the ripple component of the DC voltage across the electrolytic capacitor does not affect the stable operation of the light source module. [Means for solving the problem]

[0006] The lighting device of the present disclosure includes a full-wave rectifier circuit that rectifies the AC voltage of AC power supplied from an external power source into a DC voltage, an electrolytic capacitor that smooths the DC voltage rectified by the full-wave rectifier circuit, a supply circuit that adjusts the amount of current in the DC power supplied from the electrolytic capacitor and supplies the DC power of this adjusted amount of current to a light source module, a ripple detection unit that detects the ripple width of the DC voltage smoothed by the electrolytic capacitor, a difference detection unit that detects the difference between the detected value of the ripple width detected by the ripple detection unit and a ripple width threshold value, and a setting unit that sets the increase in the current amount per unit time when adjusting the amount of current of the DC power supplied by the supply circuit to the light source module to a larger increase the larger the difference detected by the difference detection unit. [Effects of the Invention]

[0007] The lighting device disclosed herein includes a setting unit that sets the increase in the current amount per unit time when the supply circuit, which adjusts the amount of current in the power supplied from the electrolytic capacitor and supplies the adjusted amount of DC current to the light source module, adjusts the amount of DC current supplied to the light source module to a rated current value, to a larger increase the greater the difference between the detected value of the ripple width of the DC voltage smoothed by the electrolytic capacitor and a ripple width threshold, and an instruction unit that controls the supply circuit to set the increase in the current amount per unit time when adjusting to increase the amount of DC current supplied to the light source module to the increase set by the setting unit.Since the increase in the current amount per unit time when adjusting to increase the amount of DC current supplied to the light source module to the rated current value is set according to the ripple width of the DC voltage, the increase rate of the increase in the amount of current supplied to the light source module is large, and it is possible to shorten the time it takes for the amount of DC current to reach the desired current amount from the start of supply. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a configuration of a lighting device according to a first embodiment. [Figure 2] 1 is a block diagram showing the configuration of a control device for a lighting device according to Embodiment 1. FIG. [Figure 3] 4 is a flowchart illustrating the lighting operation of the lighting device 10 according to the first embodiment. [Figure 4] 4 is a characteristic diagram showing the relationship between the temperature and capacitance of an electrolytic capacitor used in the lighting device according to the first embodiment. FIG. [Figure 5] 5 is a flowchart showing an operation of controlling the ripple width of the DC voltage of the electrolytic capacitor so as not to exceed a ripple width threshold in the lighting device according to the first embodiment. [Figure 6] 4 is a characteristic diagram illustrating the difference between the ripple width of the electrolytic capacitor of the lighting device according to the first embodiment and a ripple width threshold value. FIG. [Figure 7]4 is a characteristic diagram showing a change over time in the difference detected by the difference detection unit and a change over time in the current amount of DC power adjusted based on this difference in the lighting device according to the first embodiment. FIG. [Figure 8] 8 is an enlarged characteristic diagram showing the change over time of the difference detected by the difference detection unit during period b, and the change over time of the current amount of DC power adjusted based on this difference, among the characteristic diagrams shown in FIG. 7. FIG. [Figure 9] FIG. 10 is a block diagram showing a configuration of a lighting device that is a modified example of the lighting device according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a lighting device and an illumination device according to an embodiment will be described with reference to the drawings. In the following drawings, the same reference numerals are used to denote the same or corresponding parts.

[0010] Embodiment 1 The configuration of the lighting device 10 according to the first embodiment will be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of the lighting device 10 according to the first embodiment. The lighting device 10 shown in FIG. 1 includes a light source module 11 configured with light-emitting elements that emit light when supplied with direct current, such as LEDs (Light Emitting Diodes), organic EL (Electro Luminescence), and laser diodes, and a lighting device 12 that converts alternating current power supplied from an external power source 100 into direct current power and supplies the direct current power to the light source module 11, while controlling the amount of direct current power to be supplied to the light source module 11 to an amount of current equivalent to the amount of power required for the light source module 11 to emit light at a desired brightness.

[0011] The lighting device 12 includes a full-wave rectifier circuit 13 that rectifies AC power supplied from an external power source 100 and converts it into DC power, a first capacitor 14 that smoothes the DC power rectified by the full-wave rectifier circuit 13, a boost chopper circuit 15 that boosts the DC voltage of the DC power smoothed by the first capacitor 14, and a buck converter circuit 16 as a supply circuit that supplies DC power with an adjusted current amount to the light source module 11 by controlling the DC voltage of the DC power whose voltage has been boosted by the boost chopper circuit 15. Furthermore, the lighting device 12 has the following configuration for controlling the adjustment of the amount of current in the DC power when supplying DC power from the buck converter circuit 16 to the light source module 11. That is, the lighting device 12 has a dimming signal interface circuit 17 that receives an output command value instructing the brightness of the light source module 11 from an external dimmer 20, a control device 18 that receives a dimming control signal including the output command value from the dimming signal interface circuit 17 and sets a rated current amount, which is the amount of current of the DC power corresponding to the brightness indicated by the dimming control signal including the output command value, and an instruction unit 19 that outputs the rated current amount set by the control device 18 to the buck converter circuit 16 and controls the buck converter circuit 16 to adjust the amount of current supplied to the light source module 11 to the rated current amount. In addition, the control device 18 sets the increase in the current amount per unit time when the buck converter circuit 16 adjusts the amount of DC power supplied to the light source module 11 to increase it to the rated current amount, and the instruction unit 19 controls the buck converter circuit 16 so that the increase in the current amount per unit time when the buck converter circuit 16 adjusts the amount of current supplied to the light source module 11 to increase it to the rated current amount is the increase set by the control device 18. With the above configuration, the amount of current when the lighting device 12 supplies DC power to the light source module 11 is controlled, and DC power of an adjusted amount is supplied. Each component will be described in detail below.

[0012] The full-wave rectifier circuit 13 is a circuit that full-wave rectifies the AC voltage of the AC power supplied from the external power supply 100 and outputs DC power having a DC voltage including a ripple component. The full-wave rectified DC voltage is a DC voltage including a ripple component caused by the power supply frequency of the external power supply 100.

[0013] The first capacitor 14 is a capacitor that smoothes the DC voltage including the ripple component of the DC power output from the full-wave rectifier circuit 13 and outputs the smoothed DC voltage.

[0014] The boost chopper circuit 15 is a power factor correction circuit that boosts the DC voltage of the DC power output from the first capacitor 14 by switching operation and also corrects the power factor. The boost chopper circuit 15 has a first coil 151, a first MOSFET (Metal Oxide Semiconductor Field Effect Transistor) 152, a control circuit 153, a first diode 154, a first voltage dividing resistor 155, a second voltage dividing resistor 156, and an electrolytic capacitor 157. The first coil 151 is an electromagnetic induction element that stores energy through self-induction when DC power output from the first capacitor 14 flows, and releases the stored energy as DC power when the DC power output from the first capacitor 14 stops. The first MOSFET 152 is a field-effect transistor, and is a switching element that performs a switching operation in which, when a voltage is applied to the gate terminal, it is brought into an ON state in which DC power output from the first capacitor 14 flows to the first coil 151, and when the voltage of the gate terminal is removed, it is brought into an OFF state in which DC power flowing from the first capacitor 14 to the first coil 151 is stopped. The control circuit 153 is a circuit that boosts the DC voltage of the DC power output from the first capacitor 14 by controlling the ratio between the lengths of the ON state and OFF state of the switching operation of the first MOSFET 152. Specifically, the control circuit 153 is a circuit that detects the DC voltage across the electrolytic capacitor 157 and controls the detected DC voltage across the electrolytic capacitor 157 to become a voltage target value of the boost chopper circuit 15 that is stored in advance in the control circuit 153. For example, if the DC voltage across the electrolytic capacitor 157 is lower than the voltage target value, the control circuit 153 controls the frequency or duty ratio of the ON state and the OFF state in the switching operation of the first MOSFET 152 to be changed so that the DC voltage across the electrolytic capacitor 157 is boosted to the voltage target value. The first diode 154 is a rectifying element that controls the direction of the DC current of the DC power emitted from the first coil 151 so that it flows from the first coil 151 to the electrolytic capacitor 157 . The first voltage dividing resistor 155 and the second voltage dividing resistor 156 are resistors that divide the DC voltage across the electrolytic capacitor 157. The control circuit 153 detects the DC voltage across the electrolytic capacitor 157 by connecting to a node A between the first voltage dividing resistor 155 and the second voltage dividing resistor 156.

[0015] The electrolytic capacitor 157 is a capacitor that smoothes the DC voltage of the DC power by charging and discharging the DC power boosted by the control circuit 153. The DC power whose DC voltage has been smoothed by the electrolytic capacitor 157 is supplied from the boost chopper circuit 15 to the buck converter circuit 16.

[0016] The buck converter circuit 16 is a supply circuit that receives DC power output from the electrolytic capacitor 157 of the boost chopper circuit 15, adjusts the current amount of the DC power to the current amount instructed by the instruction unit 19, and supplies the adjusted amount of DC current to the light source module 11, and includes a second coil 161, a second MOSFET 162, a current amount control unit 163, a second diode 164, a second capacitor 165, and a current detection resistor 166. The adjustment of the current amount in this buck converter circuit 16 is performed, for example, by controlling the DC voltage of the DC power output from the electrolytic capacitor 157 of the boost chopper circuit 15 through the switching operation of the second MOSFET 162. The buck converter circuit 16, for example, steps down the DC voltage of the DC power output from the electrolytic capacitor 157 of the boost chopper circuit 15 and controls the amount of current of the DC power to be supplied to the light source module 11. The second coil 161 is an electromagnetic induction element that stores energy through a self-induction lamp when DC power output from the electrolytic capacitor 157 flows, and releases the stored energy as DC power when the DC power output from the electrolytic capacitor 157 stops. The second MOSFET 162 is a field-effect transistor, and is a switching element that performs a switching operation in which, when a voltage is applied to the gate terminal, it is brought into an ON state in which DC power output from the electrolytic capacitor 157 flows to the second coil 161, and when the voltage of the gate terminal is removed, it is brought into an OFF state in which the DC power flowing to the electrolytic capacitor 157 is stopped.

[0017] The current amount control unit 163 is a circuit that controls the DC voltage of the DC power output from the electrolytic capacitor 157 by controlling the ratio between the lengths of the ON state and OFF state of the switching operation of the second MOSFET 162, thereby adjusting the amount of current of the DC power supplied to the light source module 11. Specifically, the current amount control unit 163 is a circuit that detects the DC voltage at a node B between the light source module 11 and the current detection resistor 166, and controls to change the frequency or duty ratio of the ON state and the OFF state in the switching operation of the second MOSFET 162 so that if the detected DC voltage is higher than a target voltage corresponding to the amount of current of the DC power instructed by the instructing unit 19, the DC voltage detected at the node B is stepped down to the target voltage, and if the detected DC voltage is lower than the target voltage, the DC voltage detected at the node B is stepped up to the target voltage.

[0018] The second diode 164 is a rectifying element that controls the direction of the DC current of the DC power emitted from the second coil 161 so that it flows from the second coil 161 to the second capacitor 165 . The second capacitor 165 is charged with the DC power flowing through the second diode 164 and outputs DC power with an adjusted current amount for lighting the light source module 11 . The current detection resistor 166 is a detection resistor connected to the low potential side of the light source module 11 . The dimming signal interface circuit 17 is a circuit that receives a dimming control signal including an output command value that indicates a desired brightness of the light source module 11 and is transmitted from an external dimmer 20, and outputs the signal to the control device .

[0019] 2 is a block diagram showing the configuration of the control device 18. The control device 18 shown in FIG.

[0020] The storage device 181 is, for example, a device such as a RAM (Random Access Memory), a ROM (Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), etc. The storage device 181 stores the dimming control signal output from the dimming signal interface circuit 17 and the corresponding current amount as the rated current amount. The storage device 181 also stores a threshold value for the ripple width of the DC voltage smoothed by the electrolytic capacitor 157. The threshold value for the ripple width of the DC voltage is desirably set in accordance with an allowable value for protecting the electrolytic capacitor 157 itself or the components around the electrolytic capacitor 157. The storage device 181 also stores an increase in the amount of current supplied by the buck converter circuit 16 to the light source module 11, which corresponds to the difference between the detected value of the ripple width of the DC voltage across the electrolytic capacitor 157 and the stored threshold value of the ripple width of the DC voltage. The relationship between the difference between the detected value of the ripple width and the threshold value and the increase is such that the larger the difference, the larger the increase. The difference and the increase in this relationship are stored in the storage device 181.

[0021] The processor 182 is hardware such as a CPU (Central Processing Unit), an ASIC (Application Special Integrated Circuit), a DSP (Digital Signal Processor), or an FPGA (Field Programmable Gate Array), and constitutes a ripple detection unit 183, a difference detection unit 184, and a setting unit 185 by executing a program stored in a storage device 181 or the like.

[0022] The ripple detection unit 183 detects the potential at a node A between the first voltage dividing resistor 155 and the second voltage dividing resistor 156 connected to both ends of the electrolytic capacitor 157, detects the DC voltage across the electrolytic capacitor 157 from this potential and the resistance values ​​of the first voltage dividing resistor 155 and the second voltage dividing resistor 156, and detects the ripple width, which is the difference between the maximum and minimum values ​​of the ripple component of the electrolytic capacitor 157. The ripple detection unit 183 periodically detects the ripple width of the electrolytic capacitor 157.

[0023] The difference detection unit 184 detects the difference between the detected value of the ripple width of the DC voltage of the electrolytic capacitor 157 detected by the ripple detection unit 183 and the ripple width threshold value, which is the threshold value of the ripple width of the DC voltage stored in the storage device 181.

[0024] The setting unit 185 reads out from the storage device 181 the rated current amount corresponding to the dimming control signal output from the dimming signal interface circuit 17, sets it, and outputs it. Furthermore, when adjusting the amount of DC current supplied from the buck converter circuit 16, which is a supply circuit, after it starts supplying power to the light source module 11 until it reaches the rated current amount, the setting unit 185 reads from the storage device 181 the increase in the amount of current per unit time supplied by the buck converter circuit 16 to the light source module 11, and sets the increase in the amount of current per unit time corresponding to the difference detected by the difference detection unit 184. Since the storage device 181 stores an increase in the amount of current that increases as the difference detected by the difference detection unit 184 increases, the increase in the amount of current that is set increases as the difference detected by the difference detection unit 184 increases.

[0025] The instruction unit 19 controls the current amount control unit 163 to set the target voltage of the current amount control unit 163 of the buck converter circuit 16 to a DC voltage corresponding to the rated current amount that the buck converter circuit 16, set by the setting unit 185, supplies to the light source module 11.

[0026] Next, a description will be given of the lighting operation of lighting device 12 of lighting device 10 configured as described above. Fig. 3 is a flowchart showing the lighting operation of lighting device 10. When lighting device 10 receives a lighting start instruction from a user and a dimming control signal including an output command value instructing the desired brightness of light source module 11 transmitted from external dimmer 20, lighting device 10 starts the lighting operation.

[0027] When the lighting operation of the lighting device 10 is started, in step S101, the full-wave rectifier circuit 13 full-wave rectifies the AC power supplied from the external power supply 100 and outputs DC power containing a ripple component. The DC voltage including the ripple component of the DC power output from the full-wave rectifier circuit 13 is smoothed by the first capacitor 14 (step S102). Next, in step S103, the control circuit 153 of the boost chopper circuit 15 controls the ratio between the ON state and OFF state lengths of the switching operation of the first MOSFET 152, thereby boosting the DC voltage of the DC power output from the first capacitor 14 to the voltage target value stored in the control circuit 153. The DC voltage of the DC power boosted by the control circuit 153 is smoothed by the electrolytic capacitor 157 of the boost chopper circuit 15 (step S104). In step S105, the current amount control unit 163 of the buck converter circuit 16 controls the ratio between the ON state length and the OFF state length of the switching operation of the second MOSFET 162 to control the DC voltage of the DC power output from the electrolytic capacitor 157 to a target voltage corresponding to the current amount of the DC power instructed by the instructing unit 19, and adjusts the current amount of the output DC power so that it gradually increases up to the rated current amount. The DC power whose current amount has been adjusted by voltage control by the current amount control unit 163 has its DC voltage smoothed by the second capacitor 165 of the buck converter circuit 16 and is supplied to the light source module 11 (step S106). Through the above operations, the lighting device 12 converts the AC power supplied from the external power source 100 into DC power, controls the current amount of the converted DC power to an amount of current equivalent to the amount of power supply required for the light source module 11 to emit light at the desired brightness, and supplies it to the light source module 11, thereby causing the light source module 11 to emit light at the desired brightness.

[0028] Here, the electrolytic capacitor 157 charges and discharges the DC power boosted by the control circuit 153 to smooth the DC voltage of the DC power, but this DC voltage has a ripple width, which is the voltage fluctuation that occurs during charging and discharging. The electrolytic capacitor 157 has a characteristic that the smaller the capacitance of the electrolytic capacitor 157, the larger the ripple width of the DC voltage. FIG. 4 is a characteristic diagram showing the relationship between temperature and capacitance of electrolytic capacitor 157 used in lighting device 12 of Embodiment 1. As shown in FIG. 4, the capacitance of electrolytic capacitor 157 decreases as the temperature decreases. This is because electrolytic capacitor 157 is configured by sealing an electrolyte between the anode and cathode, and as the temperature decreases, the viscosity of the electrolyte increases, reducing the electrical conductivity of the electrolyte and thereby reducing the capacitance. In particular, in an environment where the temperature is below minus 40 degrees Celsius, the capacitance of electrolytic capacitor 157 decreases significantly as the electrolyte freezes. When the ambient temperature of lighting device 12 is low, the temperature of electrolytic capacitor 157 is also low and the capacitance is small due to the above characteristics, so if lighting device 12 is started when the ambient temperature is low, the ripple width of the output DC voltage will increase, raising concerns that this may affect the stable operation of lighting device 10. On the other hand, lighting device 12 generates heat during lighting operation, so as lighting operation continues from the start of lighting, the temperature of electrolytic capacitor 157 rises, the capacitance of electrolytic capacitor 157 increases, and the ripple width of the DC voltage of electrolytic capacitor 157 becomes smaller.

[0029] Furthermore, the electrolytic capacitor 157 has a characteristic that the smaller the current amount of the output DC power, the smaller the ripple width of the DC voltage. The current amount of the DC power output to the electrolytic capacitor 157 increases as the current amount of the DC power supplied to the light source module 11 by the buck converter circuit 16 increases. Therefore, the ripple width of the DC voltage of the electrolytic capacitor 157 has a characteristic that varies depending on the magnitude of the current amount of the DC power instructed by the instruction unit 19. Therefore, the lighting device 12 of the present disclosure controls the back converter circuit 16 instructed by the instruction unit 19 to set the amount of current of DC power to be supplied to the light source module 11 so that the detection value of the ripple width of the DC voltage of the electrolytic capacitor 157 detected by the ripple detection unit 183 does not exceed the DC voltage ripple width threshold value stored in the memory device 181. The control operation of the above-mentioned lighting device 12 will be described below.

[0030] Fig. 5 is a flowchart for explaining the operation of lighting device 12 to control the detected value of the ripple width of the DC voltage of electrolytic capacitor 157 so that it does not exceed the ripple width threshold. The operation of the flowchart in Fig. 5 is performed when buck converter circuit 16 supplies DC power to light source module 11 in a state where the capacitance of electrolytic capacitor 157 is lower than at room temperature, such as when lighting device 12 is started when the ambient temperature is low, and when the ripple width is large, the amount of DC power to be supplied is reduced, and the operation ends when the amount of DC power supplied by buck converter circuit 16 to light source module 11 reaches the rated current amount.

[0031] When this operation is started, in step S201, the ripple detection unit 183 of the control device 18 detects the DC voltage across the electrolytic capacitor 157 and detects the ripple width of the DC voltage of the electrolytic capacitor 157. Next, in step S202, the difference detection unit 184 of the control device 18 detects the difference between the detection value of the ripple width of the electrolytic capacitor 157 detected by the ripple detection unit 183 and the DC voltage ripple width threshold value stored in the storage device 181. FIG. 6 is a characteristics diagram for explaining the detection of the difference between the detected value of the ripple width of the DC voltage of electrolytic capacitor 157 and the ripple width threshold. The solid line waveform in FIG. 6 is the DC voltage across electrolytic capacitor 157, and ripple detection unit 183 detects the DC voltage across electrolytic capacitor 157 and detects ripple width detection value X, which is the difference between the maximum value C and the minimum value D of the ripple component. Storage device 181 stores, as "ripple width threshold" Y, the difference between an "upper voltage threshold" A, which defines the upper limit of the DC voltage as a threshold, and a "lower voltage threshold" B, which defines the lower limit of the DC voltage as a threshold. Difference detection unit 184 detects difference Z (=XY) between detection value X of the ripple width of the DC voltage of electrolytic capacitor 157, detected by ripple detection unit 183, and the stored "ripple width threshold" Y.

[0032] In step S203, the setting unit 185 of the control device 18 reads from the storage device 181 the increase in the amount of current per unit time that the buck converter circuit 16 supplies to the light source module 11, and sets the increase in the amount of current per unit time that corresponds to the difference detected by the difference detection unit 184. Since the storage device 181 stores an increase in the amount of current that increases as the difference detected by the difference detection unit 184 increases, the increase in the amount of current that is set increases as the difference detected by the difference detection unit 184 increases. In step S204, the instruction unit 19 controls the current amount control unit 163 to set the increase per unit time of the current amount of DC power that the buck converter circuit 16 sets to the light source module 11, which is set by the setting unit 185, to the increase set by the setting unit 185. Specifically, the instruction unit 19 controls the current amount control unit 163 to add an increase in voltage that corresponds to the increase in the current amount per unit time that is set by the setting unit 185 to a target voltage that corresponds to the current amount of DC power that is set by the current amount control unit 163 and that is supplied to the light source module 11.

[0033] In step S205, the current amount control unit 163 determines whether the value of the DC voltage detected from the contact B between the light source module 11 and the current detection resistor 166 is equal to or greater than the target voltage corresponding to the rated current amount instructed by the instructing unit 19. If the value of the DC voltage detected at the contact B is not equal to or greater than the voltage corresponding to the rated current amount, i.e., is less than the voltage (step S205, NO), the process returns to step S201, and the instructing unit 19 repeats the adjustment to increase the current amount of DC power supplied to the light source module 11 up to the rated current amount. On the other hand, if the value of the DC voltage detected at the contact B is equal to or greater than the voltage corresponding to the rated current amount (step S205, YES), in step S206, the instructing unit 19 stops the adjustment by the current amount control unit 163 to increase the current amount of DC power supplied to the light source module 11 up to the rated current amount, and sets the value of the target voltage to a value corresponding to the rated current amount. Through the above operations, the lighting device 12 increases the amount of DC power supplied to the light source module 11 to the rated current amount so that the ripple width of the DC voltage of the electrolytic capacitor 157 does not exceed the ripple width threshold, and when the amount of DC power supplied to the light source module 11 reaches the rated current amount, sets the target voltage value to a value corresponding to the rated current amount, thereby constantly supplying the amount of supply current necessary for the light source module 11 to emit light at the desired brightness.

[0034] Next, an operation will be described in which the amount of current of DC power supplied to the light source module 11 is controlled based on the difference detected by the difference detection unit 184 during the period from when the buck converter circuit 16, which is a supply circuit, starts to supply DC power to the light source module 11 until the amount of current of the supplied DC power reaches the rated current amount. Fig. 7 is a characteristic diagram showing the change over time in the difference detected by the difference detection unit 184 during the period from when the buck converter circuit 16 starts to supply power to the light source module 11 until the amount of current of the supplied DC power reaches the rated current amount, and the change over time in the amount of current of DC power supplied from the buck converter circuit 16 to the light source module 11, which is adjusted based on this difference. 7 shows the period from when the buck converter circuit 16 starts supplying power to the light source module 11 to when the amount of DC power supplied reaches the rated current amount, divided into the following periods: period a) from when the buck converter circuit 16 starts supplying power to the light source module 11 to when the difference detected by the difference detection unit 184 reaches zero; period b) from when the difference detected by the difference detection unit 184 reaches zero to when the amount of DC power supplied by the buck converter circuit 16 to the light source module 11 reaches the rated current amount; period c) from when the amount of DC power supplied by the buck converter circuit 16 to the light source module 11 reaches the rated current amount to when the temperature of the electrolytic capacitor 157 stabilizes; and period d) after the temperature of the electrolytic capacitor 157 stabilizes. Below, the relationship between the difference detected by the difference detection unit 184 and the amount of DC power supplied to the light source module 11 will be described for each of periods a to d.

[0035] At the start of period a, the temperature of electrolytic capacitor 157 is low and its capacitance is small, so the ripple width of the DC voltage of electrolytic capacitor 157 is relatively large, and a relatively large value is also detected as the difference Z1 between the detected value of ripple width and the ripple width threshold value detected by difference detection unit 184. At this time, the amount of current of DC power supplied from buck converter circuit 16 to light source module 11 is adjusted by current amount control unit 163 based on the target voltage as described above, and is adjusted to a value such that the detected value of ripple width of the DC voltage of electrolytic capacitor 157 is smaller than the ripple width threshold value at the capacitance at the temperature at which the electrolyte of electrolytic capacitor 157 freezes, so that the detected value of ripple width of the DC voltage of electrolytic capacitor 157 does not exceed the ripple width threshold value. As a result, the current amount of DC power supplied by the buck converter circuit 16 to the light source module 11 is controlled by the current amount control unit 163 to gradually increase from the start of supplying DC power until it reaches the rated current amount. Furthermore, when the buck converter circuit 16 adjusts the amount of current of DC power supplied to the light source module 11 to increase it to the rated current amount, the increase in the amount of current per unit time is set by the setting unit 185 of the control device 18, and the instruction unit 19 controls the current amount control unit 163 of the buck converter circuit 16 so that the set increase becomes the same. At this time, the setting unit 185 sets the amount of DC power to a larger increase as the difference detected by the difference detection unit 184 increases. As a result, the buck converter circuit 16 supplies to the light source module 11 DC power with an amount of current that increases by the set increase per unit time. Thus, since the increase per unit time in the amount of current of DC power supplied by the buck converter circuit 16 to the light source module 11 increases as the difference detected by the difference detection unit 184 increases, during period a when the difference detected by the difference detection unit 184 is relatively large, the rate of increase in the amount of current of DC power supplied by the buck converter circuit 16 to the light source module 11 increases, and the amount of current supplied to the light source module 11 suddenly approaches the rated current. By the amount of current supplied to the light source module 11 suddenly approaching the rated current in this way, the time required for the current supplied to the light source module 11 to reach the desired current is shortened, and the time until the light source module 11 reaches the desired brightness is shortened. As described above, when the buck converter circuit 16 increases the amount of DC power supplied to the light source module 11, the ripple width of the DC voltage of the electrolytic capacitor 157 increases. On the other hand, when DC power is supplied from the buck converter circuit 16 to the light source module 11 and the lighting device 12 performs lighting operation, heat is generated inside the lighting device 12, the temperature of the electrolytic capacitor 157 rises, and the capacitance increases, which has the effect of reducing the ripple width of the DC voltage of the electrolytic capacitor 157 over time. During this period a, the increase in ripple width accompanying the increase in the amount of current exceeds the increase in the effect of reducing the ripple width accompanying the rise in temperature of electrolytic capacitor 157. Therefore, during period a, the difference between the detected value of the ripple width of the DC voltage of electrolytic capacitor 157 and the ripple width threshold value becomes smaller than difference Z1 over time. In other words, the ripple width approaches the allowable threshold value. However, in the setting unit 185 of the control device 18 in this embodiment, the larger the difference, the larger the increase in the amount of DC power that the buck converter circuit 16 supplies to the light source module 11. In other words, the smaller the difference, the smaller the increase is set. As shown in period a in Figure 7, as the difference gradually decreases, the increase in the amount of current supplied also decreases, so the increase in the amount of current supplied also becomes gradual. By adjusting the increase in the amount of current in this way, it is possible to prevent the ripple width of the DC voltage of the electrolytic capacitor 157 from increasing suddenly and exceeding the ripple width threshold. As described above, during period a, the amount of current of DC power supplied by the buck converter circuit 16 to the light source module 11 increases, the difference decreases, and eventually the difference detected by the difference detection unit 184 reaches zero. This point is the start of period b. When the difference detected by the difference detection unit 184 reaches zero, the increase in the amount of current of DC power supplied by the buck converter circuit 16 to the light source module 11 is adjusted to zero so that the ripple width of the DC voltage of the electrolytic capacitor 157 does not exceed the ripple width threshold.

[0036] FIG. 8 is a characteristic diagram showing the change over time in the difference detected by the difference detection unit 184 similar to that shown in FIG. 7, and the change over time in the amount of DC power supplied to the light source module 11 from the buck converter circuit 16, which is adjusted based on this difference, and shows an enlarged view of period b in FIG. 7. At the start of period b, the difference is 0, so the increase in the amount of DC power supplied by the buck converter circuit 16 to the light source module 11 is adjusted to be 0, and therefore no increase in the ripple width occurs due to the increase in the amount of current. However, the effect of reducing the ripple width continues to increase as the temperature of the electrolytic capacitor 157 rises, and therefore the difference detected by the difference detection unit 184 becomes larger. As the difference increases, the difference detected by difference detector 184 reaches difference Z2 at the difference detection time following the difference detection time at the start of period b. At this time, the increase in the current amount increases in accordance with difference Z2 detected by difference detector 184, and the ripple width increases as the current amount increases. As the current amount increases, the increase in the ripple width due to the increase in the current amount exceeds the increase in the ripple width reduction effect due to the temperature rise of electrolytic capacitor 157, and the difference detected by difference detector 184 decreases and reaches zero. If the difference is zero at the next difference detection time, the increase in the current amount of DC power becomes zero and the current amount is maintained. However, even during this time, the effect of electrolytic capacitor 157 reducing the ripple width is increasing, so the difference begins to increase again. This phenomenon is repeated, and the difference fluctuates between zero and difference Z2, and the increase in the current amount changes accordingly. In this way, by controlling the amount of current in response to changes in the difference, the lighting device 12 controls the amount of DC power supplied by the buck converter circuit 16 to the light source module 11 to increase it to the rated current amount as quickly as possible, while ensuring that the detected value of the ripple width of the DC voltage of the electrolytic capacitor 157 does not exceed the ripple width threshold value. Such a relationship between the difference and the control of the current amount is repeated until the current amount of the DC power supplied from the buck converter circuit 16 to the light source module 11 reaches the rated current amount.

[0037] As described above, if the buck converter circuit 16 controls the amount of DC power supplied to the light source module 11 so as to increase it as much as possible while preventing the ripple width from exceeding the ripple width threshold, the amount of current will eventually reach the rated current. This point is the start of period c. During period c, the current amount control unit 163 controls the amount of DC power supplied from the buck converter circuit 16 to the light source module 11 so that the amount of DC power is maintained at the rated current amount, and therefore, an increase in the ripple width does not occur due to an increase in the amount of current. Meanwhile, the temperature of the electrolytic capacitor 157 continues to rise due to the lighting operation of the lighting device 12, and as a result, the effect of reducing the ripple width continues to increase, so the difference detected by the difference detection unit 184 gradually increases. Then, the amount of heat generated inside lighting device 12 due to lighting operation and the amount of heat dissipated by lighting device 12 are balanced, so the temperature of electrolytic capacitor 157 does not rise.

[0038] As described above, when lighting device 12 is operated while controlling the amount of DC power supplied from buck converter circuit 16 to light source module 11 to the rated current, the heat generation inside lighting device 12 due to the lighting operation and the heat dissipation effect of lighting device 12 eventually balance, stabilizing the temperature of electrolytic capacitor 157. Therefore, the effect of reducing the ripple width of electrolytic capacitor 157 also stabilizes. Furthermore, at this time, the amount of DC power supplied to light source module 11 is constant at the rated current, and the ripple width is also stable, so the difference also becomes constant. This point is the start of period d. At the start of period d, the difference detected by difference detector 184 is difference Z3. In this way, after the period d when the amount of DC power reaches the rated current amount and becomes stable, and the difference detected by the difference detection unit 184 also becomes stable, the lighting device 12 continues to light the light source module 11 stably at the desired brightness.

[0039] As described above, the lighting device 12 according to the first embodiment includes the full-wave rectifier circuit 13 that full-wave rectifies the AC voltage of the AC power supplied from the external power supply 100, the electrolytic capacitor 157 that smooths the DC voltage including the ripple component rectified by the full-wave rectifier circuit 13, the buck converter circuit 16 that serves as a supply circuit that adjusts the amount of current of the DC power supplied from the electrolytic capacitor 157 and supplies the DC current of the adjusted amount to the light source module 11, the ripple detection unit 183 that detects the ripple width of the DC voltage smoothed by the electrolytic capacitor 157, and the detection value of the ripple width of the DC voltage of the electrolytic capacitor 157 detected by the ripple detection unit 183. The circuit has a difference detection unit 184 that detects the difference from a ripple width threshold, which is a threshold value; a setting unit 185 that sets the increase in the current amount per unit time when the buck converter circuit 16 as a supply circuit adjusts to increase the amount of direct current supplied to the light source module 11 to a rated current amount, to a larger increase as the difference detected by the difference detection unit 184 increases; and an instruction unit 19 that controls the buck converter circuit 16 as a supply circuit to set the increase in the current amount per unit time when the buck converter circuit 16 as a supply circuit increases the amount of current supplied to the light source module 11 to the rated current amount to the increase set by the setting unit 185. Therefore, during the period (period a) from when the buck converter circuit 16 as a supply circuit starts supplying power to the light source module 11 until the difference detected by the difference detection unit 184 reaches 0, during which the difference detected by the difference detection unit 184 is relatively large, the rate of increase in the amount of DC current supplied to the light source module 11 by the buck converter circuit 16 as a supply circuit becomes large, and the amount of current supplied to the light source module 11 suddenly approaches the rated current amount, thereby shortening the time until the DC current supplied to the light source module 11 reaches the desired current amount and shortening the time until the light source module 11 reaches the desired brightness.

[0040] Furthermore, the setting unit 185 sets the increase in the amount of DC power supplied to the light source module 11 by the buck converter circuit 16 as a supply circuit to be smaller as the difference detected by the difference detection unit 184 becomes smaller. In other words, as the difference detected by the difference detection unit 184 becomes gradually smaller, the increase in the amount of DC current supplied to the light source module 11 by the buck converter circuit 16 as a supply circuit also becomes smaller, and the increase in the amount of supplied current becomes more gradual. By adjusting the increase in the amount of DC current supplied to the light source module 11 by the buck converter circuit 16 as a supply circuit in this way, it is possible to prevent the ripple width of the DC voltage of the electrolytic capacitor 157 from increasing suddenly and exceeding the ripple width threshold.

[0041] Next, illumination device 30, which is a modified example of the configuration of illumination device 10 of embodiment 1, will be described with reference to Fig. 9. Fig. 9 is a block diagram showing the configuration of illumination device 30, which is a modified example of illumination device 10. The configuration of illumination device 30 according to the modified example will be described, focusing on the differences from embodiment 1. The lighting device 12 of the first embodiment has been described as a device in which a boost chopper circuit 15 using a first coil 151 in an electromagnetic induction element is implemented as a power factor improvement circuit, but the lighting device 32 of the modified example, as shown in FIG. 9, has a flyback circuit 35 using a transformer 351 in which the input coil and the output coil are insulated in an electromagnetic induction element as a power factor improvement circuit. The flyback circuit 35 includes a transformer 351 that boosts the DC voltage of the DC power output from the first capacitor 14, a first MOSFET 352 that performs a switching operation to switch between an ON state in which DC power flows to the transformer 351 and an OFF state in which DC power flow to the input coil of the transformer 351 is stopped, a control circuit 353 that controls the switching operation of the first MOSFET 352, a first diode 354 that controls the direction of the DC current of the DC power released from the output coil of the transformer 351 to flow from the transformer 351 to an electrolytic capacitor 357, a first voltage dividing resistor 355 and a second voltage dividing resistor 356 that divide the DC voltage across the electrolytic capacitor 357, and an electrolytic capacitor 357 that smoothes the DC voltage of the DC power released from the transformer 351. This transformer 351 is an electromagnetic induction element in which the input side coil and the output side coil are insulated, and when DC power output from the first capacitor 34 flows, it stores energy in the input side coil by self-induction, and when the DC current output from the first capacitor 34 stops, it releases the stored energy as DC power from the output side coil. The first MOSFET 352 is a switching element that performs a switching operation in which, when a voltage is applied to the gate terminal, it is brought into an ON state in which DC power output from the first capacitor 34 flows to the input coil of the transformer 351, and when the voltage of the gate terminal is removed, it is brought into an OFF state in which DC power flowing from the first capacitor 34 to the input coil of the transformer 351 is stopped. The control circuit 353 is a circuit that boosts the DC voltage of the DC power output from the first capacitor 14 by controlling the ratio between the lengths of the ON state and OFF state of the switching operation of the first MOSFET 352. Specifically, the control circuit 353 is a circuit that detects the DC voltage across the electrolytic capacitor 357 and controls the detected DC voltage across the electrolytic capacitor 357 to become a voltage target value of the flyback circuit 35 that is stored in advance in the control circuit 353. For example, if the DC voltage across the electrolytic capacitor 357 is lower than the voltage target value, the control circuit 353 controls the frequency or duty ratio of the ON state and the OFF state in the switching operation of the first MOSFET 352 to be changed so that the DC voltage across the electrolytic capacitor 357 is boosted to the voltage target value. The first diode 354 is a rectifying element that controls the direction of the DC current of the DC power discharged from the output coil of the transformer 351 so that it flows from the output coil of the transformer 351 to the electrolytic capacitor 357 . The first voltage dividing resistor 355 and the second voltage dividing resistor 356 are resistors that divide the DC voltage across the electrolytic capacitor 357. The control circuit 353 detects the DC voltage across the electrolytic capacitor 357 by connecting to a node C between the first voltage dividing resistor 355 and the second voltage dividing resistor 356. The electrolytic capacitor 357 is a capacitor that smoothes the DC voltage of the DC power by charging and discharging the DC power boosted by the control circuit 353. The DC power smoothed by the electrolytic capacitor 357 is supplied from the flyback circuit 35 to the supply circuit.

[0042] The lighting device 32 of the modified example configured as described above is equipped with a flyback circuit 35 using a transformer 351 in which the input coil and output coil of the transformer 351 are insulated as a power factor improvement circuit. Therefore, compared to the non-insulated boost chopper circuit 15 of the first embodiment that uses the first coil 151 as an electromagnetic induction element, it is possible to block conducted noise and prevent electric shock, thereby improving safety.

[0043] Furthermore, the lighting device 12 of the first embodiment has been described as a device that includes, as a supply circuit, a buck converter circuit 16 in which a current amount control unit 163 changes the frequency or duty ratio of the ON state and OFF state in the switch operation of the second MOSFET 162 to adjust the amount of DC power discharged from the second coil 161, thereby controlling the amount of DC power supplied to the light source module 11. However, the lighting device 32 of the modified example includes, as a supply circuit, a constant current circuit 36 ​​that controls the amount of DC power supplied to the light source module 11 by variably adjusting the impedance of the second MOSFET 362, as shown in FIG. 9 . The constant current circuit 36 ​​includes a second MOSFET 362 whose impedance can be variably adjusted, a current detection resistor 366 connected in series with the light source module 11, and a current amount control unit 363 that controls the impedance of the second MOSFET 362. The second MOSFET 362 is an element that can variably adjust the impedance between the drain terminal and the source terminal depending on the magnitude of the voltage applied to the gate terminal. The current detection resistor 366 is a detection resistor connected in series to the low potential side of the light source module 11 . The current amount control unit 363 changes the magnitude of the voltage applied to the gate terminal of the second MOSFET 362 and variably controls the impedance of the second MOSFET 362, thereby controlling the current amount of DC power output from the electrolytic capacitor 357. Specifically, the current amount control unit 363 detects the potential of a node D between the light source module 11 and a current detection resistor 366 connected in series with the light source module 11, and adjusts the voltage applied to the gate terminal of the second MOSFET 363 so that a DC voltage detected from the detected potential and the resistance value of the current detection resistor 366 becomes equal to a target voltage corresponding to the current amount of DC power instructed by the instruction unit 39. The rest of the configuration is the same as that described in the first embodiment.

[0044] The lighting device 32 of the modified example configured as described above has implemented as its supply circuit a constant current circuit 36 ​​in which the current amount control unit 363 controls the amount of current of DC power supplied to the light source module 11 by adjusting the impedance of the second MOSFET 362. Therefore, compared to the buck converter circuit 16 of the first embodiment in which the current amount control unit 163 adjusts the amount of current of DC power released from the second coil 161 by changing the frequency or duty ratio of the ON state and OFF state in the switch operation of the second MOSFET 162, the lighting device 32 does not require the second diode 164 that controls the direction of flow of the DC current of the DC power released from the second coil 161 and the second capacitor 165 that charges the DC power flowing through the second diode 164 and outputs the DC power adjusted to light the light source module 11, and can supply DC power to the light source module 11 with a circuit of a simple configuration.

[0045] In the lighting device 32 according to the modified example having such a configuration, a flyback circuit 35 is implemented as a power factor improvement circuit, and a constant current circuit 36 ​​is implemented as a supply circuit, thereby providing a simple and highly safe device. Furthermore, similar to the lighting device 10 of the first embodiment, the lighting device 12 according to the modified example includes a full-wave rectifier circuit 13 that full-wave rectifies the AC voltage of the AC power supplied from the external power supply 100, an electrolytic capacitor 357 that smooths the DC voltage including the ripple component rectified by the full-wave rectifier circuit 13, a constant current circuit 36 ​​that adjusts the current amount of the DC power supplied from the electrolytic capacitor 357 and supplies the DC current of the adjusted current amount to the light source module 11, a ripple detection unit 183 that detects the ripple width of the DC voltage smoothed by the electrolytic capacitor 357, and a constant current circuit 36 ​​that detects the ripple width of the DC voltage of the electrolytic capacitor 357 detected by the ripple detection unit 183. The control circuit includes a difference detection unit 184 that detects the difference between the detected value and a ripple width threshold that is a threshold value for the ripple width; a setting unit 185 that sets the increase in the current amount per unit time when the constant current circuit 36 ​​as a supply circuit adjusts to increase the amount of direct current supplied to the light source module 11 to the rated current amount, to a larger increase as the difference detected by the difference detection unit 184 increases; and an instruction unit 19 that controls the constant current circuit 36 ​​as a supply circuit to set the increase in the current amount per unit time when the constant current circuit 36 ​​as a supply circuit increases the amount of current supplied to the light source module 11 to the rated current amount to the increase set by the setting unit 185. Therefore, during the period (period a) from when the constant current circuit 36 ​​as a supply circuit starts supplying power to the light source module 11 until the difference detected by the difference detection unit 184 reaches 0, during which the difference detected by the difference detection unit 184 is relatively large, the rate of increase in the amount of DC current supplied to the light source module 11 by the constant current circuit 36 ​​as a supply circuit becomes large, and the amount of current supplied to the light source module 11 suddenly approaches the rated current amount, thereby shortening the time until the DC current supplied to the light source module 11 reaches the desired current amount and shortening the time until the light source module 11 reaches the desired brightness.

[0046] Furthermore, the setting unit 185 sets the increase in the amount of DC power supplied to the light source module 11 by the constant current circuit 36 ​​as a supply circuit to be smaller as the difference detected by the difference detection unit 184 becomes smaller. In other words, as the difference detected by the difference detection unit 184 becomes gradually smaller, the increase in the amount of DC current supplied to the light source module 11 by the constant current circuit 36 ​​as a supply circuit also becomes smaller, and the increase in the amount of supplied current becomes more gradual. By adjusting the increase in the amount of DC current supplied to the light source module 11 by the constant current circuit 36 ​​as a supply circuit in this way, it is possible to prevent the ripple width of the DC voltage of the electrolytic capacitor 357 from increasing suddenly and exceeding the ripple width threshold.

[0047] The difference detection unit 184 constituting the control device 18 in the above-described first embodiment and the modified example detects the difference between the detected value of the ripple width of the DC voltage of the electrolytic capacitor 157 detected by the ripple detection unit 183 and the DC voltage ripple width threshold value stored in the memory device 181. However, as shown in the characteristic diagram of FIG. 6, it may also detect the difference E (=A-C) between the maximum value C of the ripple component of the DC voltage of the electrolytic capacitor 157 detected by the ripple detection unit 183 and the upper voltage threshold value A, which is the upper limit of the ripple width of the DC voltage, stored in the memory device 181, or it may detect the difference F (=D-B) between the minimum value D of the ripple component of the DC voltage of the electrolytic capacitor 157 detected by the ripple detection unit 183 and the lower voltage threshold value B, which is the lower limit of the ripple width of the DC voltage, stored in the memory device 181. [Explanation of symbols]

[0048] 10 lighting device, 11 light source module, 12 lighting device, 13 full-wave rectifier circuit, 14 first capacitor, 15 boost chopper circuit, 16 buck converter circuit, 17 dimming interface circuit, 18 control device, 19 indicator, 20 dimmer, 30 lighting device, 32 lighting device, 35 flyback circuit, 36 constant current circuit, 100 external power supply, 151 first coil, 152 first MOSFET, 153 control circuit, 154 first diode, 155 first voltage dividing resistor, 156 second voltage dividing resistor, 157 electrolytic capacitor, 161 second coil, 162 second MOSFET, 163 current amount control unit, 164 second diode, 165 second capacitor, 166 current detection resistor, 181 storage device, 182 processor, 183 ripple detection unit, 184 difference detection unit, 185 setting unit, 351 Transformer, 352 first MOSFET, 353 control circuit, 354 first diode, 355 first voltage dividing resistor, 356 second voltage dividing resistor, 357 electrolytic capacitor, 362 second MOSFET, 363 current amount control section, 366 current detection resistor.

Claims

1. a full-wave rectifier circuit that rectifies the AC voltage of the AC power supplied from the external power supply into a DC voltage; an electrolytic capacitor that smoothes the DC voltage rectified by the full-wave rectifier circuit; a supply circuit that adjusts the amount of current in the DC power supplied from the electrolytic capacitor and supplies the DC power with the adjusted amount of current to the light source module; a ripple detection unit that detects a ripple width of the DC voltage smoothed by the electrolytic capacitor; a difference detection unit that detects a difference between a ripple width detection value detected by the ripple detection unit and a ripple width threshold value; a setting unit that sets an increase in the amount of current per unit time when the supply circuit adjusts the amount of current of the DC power supplied to the light source module to a rated current amount, the increase being greater as the difference detected by the difference detection unit is greater; and an instruction unit that controls the supply circuit to adjust the amount of increase in the current amount per unit time when adjusting the supply circuit to increase the current amount of the DC power supplied to the light source module to the amount of increase set by the setting unit; A lighting device comprising:

2. 2. The lighting device according to claim 1, wherein when the difference detected by the difference detection unit becomes zero, the setting unit adjusts the increase in current amount per unit time to zero when adjusting the current amount of the DC power supplied by the supply circuit to the light source module to increase it to the rated current amount.

3. 3. The lighting device according to claim 1, wherein, when the current amount of the DC power supplied by the supply circuit to the light source module is equal to or greater than the rated current amount, the instruction unit stops adjusting the current amount of the DC power supplied to the light source module to increase it to the rated current amount, and sets the current amount of the DC power supplied to the light source module to the rated current amount.

4. The lighting device according to claim 1 or 2; the light source module to which the DC power is supplied from the lighting device; A lighting device comprising:

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