JP2016115534A - Power supply device and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device and a lighting system, temperature rise of the circuit components of which is suppressed.SOLUTION: A first step-down chopper circuit 22 steps down a DC voltage, outputted from a step-up chopper circuit 21, to a desired voltage before being applied to a first LED light source 31. A second step-down chopper circuit 23 steps down a DC voltage, outputted from the step-up chopper circuit 21, to a desired voltage before being applied to a second LED light source 32. The components of the step-up chopper circuit 21, first step-down chopper circuit 22, and second step-down chopper circuit 23 are mounted on one circuit board. In the circuit board, component arrangement is set so that the mounting area of the first step-down chopper circuit 22 is arranged between the mounting area of the second step-down chopper circuit 23 having a larger maximum current compared with the first step-down chopper circuit 22, and the mounting area of the step-up chopper circuit 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply device and a lighting device, and more particularly to a power supply device and a lighting device that light a light emitting diode.

  Conventionally, a power supply device as disclosed in Patent Document 1 has been proposed as a power supply device that turns on a light emitting diode (LED). The power supply device disclosed in Patent Document 1 uses two types of LED arrays with different emission color temperature as light sources, and adjusts the current flowing through the two types of LED arrays to change the color temperature of the mixed color light. Yes.

JP2011-258517A

  Since the light output of the LED is proportional to the forward current flowing through the LED, it is necessary to pass a large forward current through the LED in order to increase the light output of the LED. When the forward current flowing through the LED is increased, there is a problem that heat generation of a circuit component such as a switching element that controls the forward current flowing through the LED increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power supply device and a lighting device that suppress the temperature rise of circuit components.

  The power supply device of the present invention includes a voltage conversion circuit that converts an input voltage into a DC voltage having a desired voltage value, and steps down the DC voltage output from the voltage conversion circuit to a desired voltage and applies it to a corresponding LED light source. A plurality of step-down chopper circuits, and a circuit board on which components of the voltage conversion circuit and the plurality of step-down chopper circuits are mounted, and the circuit board has the largest maximum current among the plurality of step-down chopper circuits. The component placement is set so that the mounting region of the remaining step-down chopper circuit is placed between the mounting region of the step-down chopper circuit and the mounting region of the voltage conversion circuit.

  An illumination device of the present invention includes the power supply device described above, a plurality of LED light sources connected to each of the plurality of step-down chopper circuits, and an appliance body that holds the plurality of LED light sources. .

  ADVANTAGE OF THE INVENTION According to this invention, the power supply device and the illuminating device which suppressed the temperature rise of the circuit component can be provided.

It is a circuit diagram of the illuminating device of embodiment. It is a figure which shows the relationship between the color temperature of the output light by the illuminating device of embodiment, and output current. It is a perspective view of the illuminating device of embodiment. It is a disassembled perspective view of the illuminating device of embodiment. It is a disassembled perspective view of the power supply device of an embodiment. FIG. 6A is a plan view of the mounting board provided in the power supply device of the embodiment as viewed from the front side, and FIG. 6B is a plan view of the mounting board provided in the power supply device of the embodiment as viewed from the back side. It is a circuit diagram which shows another structure of the illuminating device of embodiment. It is another top view of the power supply device of an embodiment, and is a top view of the mounting board with which a power supply device is provided.

  Hereinafter, a power supply device according to the present embodiment and a lighting device using the power supply device will be described with reference to the drawings. However, the configuration described below is merely an example of the present invention. The present invention is not limited to the following embodiments, and various modifications can be made according to the design and the like as long as they do not depart from the technical idea of the present invention.

  FIG. 1 is a circuit diagram of the illumination device 1 of the present embodiment. The illumination device 1 includes a power supply device 2 and a light source unit 3.

  The light source unit 3 includes a first LED light source 31 connected between the terminals P21 and P22, and a second LED light source 32 connected between the terminals P21 and P23. In the present embodiment, the color temperature of the emitted color is different between the first LED light source 31 and the second LED light source 32. The first LED light source 31 includes a plurality of (for example, 72) light emitting diodes LD1 whose emission color is daylight color (color temperature is about 6000 K). The plurality of light emitting diodes LD1 are connected in series between the terminal P21 and the terminal P22 in a direction in which a current flows from the terminal P21 to the terminal P22. The second LED light source 32 includes a plurality of (for example, 72) light emitting diodes LD2 whose emission color is a light bulb color (color temperature is about 3000K). The plurality of light emitting diodes LD2 are connected in series between the terminal P21 and the terminal P23 in a direction in which a current flows from the terminal P21 to the terminal P23.

  The power supply device 2 includes a rectifier circuit 20, a step-up chopper circuit 21 as a voltage conversion circuit, a first step-down chopper circuit 22, a second step-down chopper circuit 23, a first control circuit 25, and a second control circuit 26. Is provided.

  The rectifier circuit 20 is composed of a diode bridge, and full-wave rectifies the AC voltage input from the AC power source 100 such as a commercial AC power source.

  The step-up chopper circuit 21 smoothes the pulsating voltage input from the rectifier circuit 20 and converts it into a DC voltage having a desired voltage value (for example, about 400 V). The step-up chopper circuit 21 includes a choke coil L1, a switching element Q1, a diode D1, and a smoothing capacitor C1 such as an electrolytic capacitor. One end of the choke coil L1 is connected to the output terminal of the rectifier circuit 20 on the high potential side (positive electrode side). A switching element Q1 made of a field effect transistor is connected between the other end of the choke coil L1 and the output terminal on the low potential side (negative electrode side) of the rectifier circuit 20. The anode of the diode D1 is connected to the connection point between the choke coil L1 and the switching element Q1. A smoothing capacitor C1 made of an electrolytic capacitor is connected between the output terminal on the low potential side of the rectifier circuit 20 and the cathode of the diode D1.

  The first control circuit 25 applies a drive signal to the gate of the switching element Q1 to turn on / off the switching element Q1 at a high frequency, thereby causing the boosting chopper circuit 21 to perform a boosting operation. The first control circuit 25 controls the on-duty and frequency of the drive signal applied to the switching element Q1 so that the output voltage of the boost chopper circuit 21 becomes a desired voltage value (for example, 400 V).

  The first step-down chopper circuit 22 includes a diode D2, a smoothing capacitor C2, a choke coil L2, a switching element Q2, and resistors R21 to R23. A series circuit of a smoothing capacitor C2, a choke coil L2, and a switching element Q2 is connected between the output terminals of the boost chopper circuit 21 (between both ends of the smoothing capacitor C1). The cathode of the diode D2 is connected to the output terminal on the high potential side of the boost chopper circuit 21, and the anode of the diode D2 is connected to the connection point between the choke coil L2 and the switching element Q2. Both ends of the smoothing capacitor C2 are connected to output terminals P11 and P12. The output terminal P11 is electrically connected to the terminal P21 of the light source unit 3 via an electric wire, and the output terminal P12 is electrically connected to the terminal P22 of the light source unit 3 via an electric wire, and between both ends of the smoothing capacitor C2. In addition, the first LED light source 31 is electrically connected. A discharging resistor R21 is connected between both ends of the smoothing capacitor C2. A series circuit of resistors R22 and R23 is connected in parallel with the series circuit of the choke coil L2 and the switching element Q2, and the voltage V23 across the resistor R23 is input to the second control circuit 26. The drive signal VQ2 is input from the second control circuit 26 to the drive electrode of the switching element Q2. The on / off of the switching element Q2 is controlled by the second control circuit 26. The switching element Q2 is repeatedly turned on / off at a high frequency (about 50 kHz), so that the first step-down chopper circuit 22 performs a step-down operation.

  The second step-down chopper circuit 23 includes a diode D3, a smoothing capacitor C3, a choke coil L3, a switching element Q3, and resistors R31 to R33. A series circuit of a smoothing capacitor C3, a choke coil L3, and a switching element Q3 is connected between the output terminals of the boost chopper circuit 21. The cathode of the diode D3 is connected to the output terminal on the high potential side of the boost chopper circuit 21, and the anode of the diode D3 is connected to the connection point between the choke coil L3 and the switching element Q3. Both ends of the smoothing capacitor C3 are connected to output terminals P11 and P13. The output terminal P13 is electrically connected to the terminal P23 of the light source unit 3 through an electric wire, and the second LED light source 32 is electrically connected between both ends of the smoothing capacitor C3. A discharging resistor R31 is connected between both ends of the smoothing capacitor C3. A series circuit of resistors R32 and R33 is connected in parallel with the series circuit of the choke coil L3 and the switching element Q3, and the voltage V33 across the resistor R33 is input to the second control circuit 26. A drive signal VQ3 is input from the second control circuit 26 to the drive electrode of the switching element Q3, and ON / OFF of the switching element Q3 is controlled by the second control circuit 26. The switching element Q3 is repeatedly turned on / off at a high frequency (about 50 kHz), so that the second step-down chopper circuit 23 performs a step-down operation.

  The second control circuit 26 receives the toning signal S1 and the dimming signal S2 from the external setting device 200. The second control circuit 26 determines the on-duty and frequency of the drive signal VQ2 applied to the switching element Q2 and the on-duty of the drive signal VQ3 applied to the switching element Q3 based on the toning signal S1 and the dimming signal S2. Control the frequency. The second control circuit 26 controls the output voltage V1 of the first step-down chopper circuit 22 and the output voltage V2 of the second step-down chopper circuit 23, respectively, so that the light output of the first LED light source 31 and the light output of the second LED light source 32 are changed. Each is controlled. Thereby, the color temperature and light flux of the light (output light of the illumination device 1) obtained by mixing the output light of the first LED light source 31 and the output light of the second LED light source 32 are controlled.

  Here, the toning operation by the second control circuit 26 will be described with reference to FIG. 2 indicates the relationship between the output current of the first step-down chopper circuit 22 (load current flowing through the first LED light source 31) I1 and the color temperature during color adjustment. The solid line in FIG. 2 indicates the relationship between the output current (load current flowing through the second LED light source 32) I2 of the second step-down chopper circuit 23 and the color temperature during color adjustment.

  The operation when the toning signal S1 for setting the color temperature to 3000K and the dimming signal S2 for maximizing the luminous flux are input from the setting device 200 to the second control circuit 26 will be described. In this case, the second control circuit 26 determines the on-duty and frequency of the drive signal VQ2 so that the output current I1 of the first step-down chopper circuit 22 is zero (current value I11). Further, the second control circuit 26 determines the on-duty and frequency of the drive signal VQ3 so that the output current I2 of the second step-down chopper circuit 23 becomes the maximum value (current value I21). Under the control of the second control circuit 26, the first LED light source 31 having a daylight white emission color is turned off, and the second LED light source 32 having a light bulb color is turned on with the maximum brightness. 3000K (bulb color temperature).

  The operation when the toning signal S1 for setting the color temperature to 6000K and the dimming signal S2 for maximizing the luminous flux are input from the setting device 200 to the second control circuit 26 will be described. In this case, the second control circuit 26 determines the on-duty and frequency of the drive signal VQ2 so that the output current I1 of the first step-down chopper circuit 22 is the maximum value (current value I13). The second control circuit 26 determines the on-duty and frequency of the drive signal VQ3 so that the output current I2 of the second step-down chopper circuit 23 is zero (current value I23). Under the control of the second control circuit 26, the first LED light source 31 whose emission color is daylight white is turned on at the maximum brightness, and the second LED light source 32 whose emission color is a light bulb color is turned off. 6000K (day white color temperature).

  A toning signal S1 for setting a color temperature higher than 3000K and lower than 6000K (for example, 4000K) and a dimming signal S2 for maximizing the luminous flux are input from the setting device 200 to the second control circuit 26. The operation in the case of being performed will be described. In this case, the second control circuit 26 has a current value smaller than the maximum value (current value I13) of the output current I1 of the first step-down chopper circuit 22, and is a current value set in advance according to the toning signal S1. The on-duty and frequency of the drive signal VQ2 are determined so as to be I12. Further, the second control circuit 26 has a current value I22 that is smaller than the maximum value (current value I21) of the output current I2 of the second step-down chopper circuit 23, and is preset according to the toning signal S1. As such, the on-duty and frequency of the drive signal VQ3 are determined. Under the control of the second control circuit 26, each of the first LED light source 31 and the second LED light source 32 is lit with brightness set in advance according to the toning signal S1, and the light source unit 3 is set with the toning signal S1 as a whole. Illuminated at a selected color temperature (for example, 4000K).

  When the color temperature of the mixed color light (light source unit 3) is increased, the second control circuit 26 increases the current I1 flowing through the first LED light source 31 and reduces the current I2 flowing through the second LED light source 32. The outputs of the chopper circuit 22 and the second step-down chopper circuit 23 are controlled. When the color temperature of the mixed color light (light source unit 3) is lowered, the second control circuit 26 reduces the current I1 flowing through the first LED light source 31 and increases the current I2 flowing through the second LED light source 32. The outputs of the chopper circuit 22 and the second step-down chopper circuit 23 are controlled.

  Next, the dimming operation by the second control circuit 26 will be described with reference to FIG.

  Dimming and toning when the toning signal S1 for setting the color temperature to 4000K and the dimming signal S2 for setting the luminous flux to 0.5 times the maximum value are input from the setting device 200 to the second control circuit 26. The operation will be described. In this case, the second control circuit 26 determines the on-duty and frequency of the drive signal VQ2 so that the output current I1 of the first step-down chopper circuit 22 has a current value I14 that is 0.5 times the current value I12. The second control circuit 26 determines the on-duty and frequency of the drive signal VQ3 so that the output current I2 of the second step-down chopper circuit 23 is set to a current value I24 that is 0.5 times the current value I22. In general, since the light flux emitted from the light emitting diode is proportional to the magnitude of the current flowing through the light emitting diode, the second control circuit 26 uses the current flowing through the light emitting diode to make the light flux 0.5 times the maximum value. The current value when the luminous flux becomes the maximum value is controlled to 0.5 times. By the dimming and toning control of the second control circuit 26, the first LED light source 31 and the second LED light source 32 are respectively lit with preset brightness, and the color temperature of the mixed color light (light source unit 3) is the toning signal S1. The light flux is controlled to about 0.5 times the maximum value.

  The second control circuit 26 is supplied with a voltage V23 across the resistor R23 and a voltage V33 across the resistor R33. The second control circuit 26 determines the presence / absence of an abnormality in the circuit by comparing the voltage V23 and the voltage V23 with a predetermined reference value. When the both-end voltage V23 exceeds a predetermined reference value or the both-end voltage V33 exceeds a predetermined reference value, the second control circuit 26 determines that an abnormality has occurred and turns off the switching elements Q2, Q3, Stops the step-down operation.

  Next, the structure of the illuminating device 1 is demonstrated based on FIG.3 and FIG.4. The lighting device 1 of the present embodiment is a ceiling-mounted lighting device.

  The lighting device 1 includes an appliance main body 11 attached to a ceiling material, and a light source unit 3 attached to the appliance main body 11 in a detachable manner.

  The instrument body 11 is formed by pressing a sheet metal, and a recess 12 for accommodating the light source unit 3 is formed on the lower surface over the entire length of the instrument body 11.

  As shown in FIG. 4, the light source unit 3 covers the two circuit boards 41, a long attachment member 42 to which the two circuit boards 41 are attached in the longitudinal direction, and the two circuit boards 41. And a cover 43 attached to the attachment member 42.

  The circuit board 41 is formed of an elongated rectangular plate-like printed wiring board. On the lower surface of the circuit board 41 (the surface facing the cover 43), a plurality of light emitting diodes LD1 constituting the first LED light source 31 are mounted so as to be arranged at substantially equal intervals along the longitudinal direction of the circuit board 41. . Similarly, a plurality of light emitting diodes LD <b> 2 constituting the second LED light source 32 are mounted on the lower surface of the circuit board 41 so as to be arranged at substantially equal intervals along the longitudinal direction of the circuit board 41. The light emitting diodes LD1 and LD2 may be alternately mounted in the longitudinal direction of the circuit board 41 so that the light from the light emitting diodes LD1 and LD2 can be easily mixed.

  One of the two circuit boards 41 (the right side in FIG. 4) is provided with a connector 411 that is electrically connected to the output terminals P11 to P13 of the power supply device 2 via electric wires. The conductive path of the copper foil used as P21-P23 is formed. Each of the two circuit boards 41 is provided with a connector 412 that electrically connects the two circuit boards 41 at a portion facing the adjacent circuit board 41. By connecting the connectors 412 of the two circuit boards 41 to each other, the power supplied from the power supply device 2 to one circuit board 41 (right side in FIG. 4) is transferred from one circuit board 41 to the other (in FIG. 4). To the left side of the circuit board 41. In the present embodiment, two circuit boards 41 on which the light emitting diodes LD1 and LD2 are mounted are provided. However, the number of circuit boards 41 can be appropriately changed according to the required number of the light emitting diodes LD1 and LD2. .

  The attachment member 42 is formed in a substantially U shape in cross section as viewed from the longitudinal direction by bending the sheet metal. Two circuit boards 41 are attached to the lower surface of the attachment member 42 in the longitudinal direction with the mounting surfaces of the light emitting diodes LD1 and LD2 facing downward. The power supply device 2 and the terminal block 4 are attached to the upper surface of the attachment member 42. An input line of the power supply device 2 is electrically connected to the terminal block 4. The terminal block 4 is connected to a power line exposed from the back side of the ceiling material to the indoor side (lower side) through the ceiling material, and the power line and the power supply device 2 are electrically connected via the terminal block 4. The terminal block 4 is attached to the upper surface of the attachment member 42 via the attachment fitting 5.

  The cover 43 is made of a synthetic resin material having translucency and diffusibility (for example, milky white acrylic resin) and is formed in a long shape with an upper surface (surface on the mounting member 42 side) opened. The cover 43 is formed in a semicircular shape that is convex downward in a side view, and is attached to the attachment member 42 so as to cover the two circuit boards 41.

  The power supply device 2 is attached to the upper surface of the attachment member 42. As illustrated in FIGS. 4 and 5, the power supply device 2 includes a circuit board 51, a case 52, and an insulating sheet 53.

  As shown in FIGS. 4 and 5, the case 52 is formed in a box shape having an open bottom surface by pressing a sheet metal. The case 52 is fixed to the upper surface of the mounting member 42 with the circuit board 51 housed inside.

  The insulating sheet 53 is made of a synthetic resin having an insulating property and has a U-shaped side view. The insulating sheet 53 is disposed along the inner surface of the case 52 and electrically insulates the case 52 and the circuit board 51.

  The circuit board 51 is composed of a printed wiring board formed in an elongated rectangular plate shape. The circuit board 51 is a double-sided mounting board (see FIGS. 6A and 6B). On the front and back surfaces of the circuit board 51, the circuit of the power supply device 2 shown in FIG. 1 (rectifier circuit 20, step-up chopper circuit 21, first step-down chopper circuit 22, second step-down chopper circuit 23, first control circuit 25, first control circuit 25, Component parts constituting the control circuit 26) are mounted.

  Here, the mounting area of the step-up chopper circuit 21, the mounting area of the first step-down chopper circuit 22, and the mounting area of the second step-down chopper circuit 23 are arranged in the longitudinal direction of the circuit board 51 on both the front and back sides of the circuit board 51. The parts arrangement is designed to line up. That is, the first step-down chopper circuit 22 that lights the daylight-colored first LED light source 31 between the mounting region of the second step-down chopper circuit 23 that lights the bulb-colored second LED light source 32 and the mounting region of the step-up chopper circuit 21. The mounting area is arranged.

  With recent technological development, the luminous efficiency of light emitting diodes has been improving year by year. Generally, light bulb color type light emitting diodes with low color temperature of light emitting color are daylight color type light emitting diodes with high color temperature of light emitting color. The luminous efficiency is lower than that. Therefore, compared with the daylight color type light emitting diode LD1 constituting the first LED light source 31, the light bulb color type light emitting diode LD2 constituting the second LED light source 32 has lower luminous efficiency. Therefore, in order to obtain the same level of light output, it is necessary to pass a larger amount of current than the first LED light source 31 to the second LED light source 32, which is second than the maximum current (current value I13) of the first step-down chopper circuit 22. The maximum current (current value I21) of the step-down chopper circuit 23 is larger. Therefore, it is expected that the heat generated by the choke coil L3, the switching element Q3, and the diode D3 of the second step-down chopper circuit 23 is larger than the heat generated by the choke coil L2, the switching element Q2, and the diode D2 of the first step-down chopper circuit 22. The Further, since the boost chopper circuit 21 supplies power to both the first step-down chopper circuit 22 and the second step-down chopper circuit 23, the step-up chopper circuit 21 includes the first step-down chopper circuit 22 and the second step-down chopper circuit 22. A current greater than 23 may flow. Therefore, the heat generated by the choke coil L1, the switching element Q1, and the diode D1 of the boost chopper circuit 21 may be larger than the heat generated by the first step-down chopper circuit 22 and the second step-down chopper circuit 23.

  The circuit board 51 provided in the power supply device 2 of the present embodiment has a terminal to which a power supply line from the AC power supply 100 is connected at one end side in the longitudinal direction (left side in FIGS. 6A and 6B). The other end side in the longitudinal direction of the circuit board 51 (the right side in FIGS. 6A and 6B) is connected to an output terminal (the above-described output terminals P11, P12,. P13) is provided. On the circuit board 51, the mounting region of the step-up chopper circuit 21, the mounting region of the first step-down chopper circuit 22, and the mounting region of the second step-down chopper circuit 23 are sequentially arranged from the left side to the right side in FIGS. 6A and 6B. The component arrangement is set so that they line up. Therefore, in the circuit board 51, between the mounting region of the second step-down chopper circuit 23 having the largest maximum current among the first step-down chopper circuit 22 and the second step-down chopper circuit 23 and the mounting region of the step-up chopper circuit 21. A mounting region for the first step-down chopper circuit 22 is disposed. Thereby, compared with the case where the mounting area | region of the step-up chopper circuit 21 and the mounting area | region of the 2nd step-down chopper circuit 23 are adjacent, the temperature rise of a circuit component can be suppressed and the lifetime of a circuit component can be lengthened. Thus, the life of the power supply device 2 can be extended.

  As described above, the power supply device 2 of the present embodiment includes the voltage conversion circuit (step-up chopper circuit 21), the plurality of step-down chopper circuits (first step-down chopper circuit 22, second step-down chopper circuit 23), circuit board 51, Is provided. The voltage conversion circuit converts the input voltage into a DC voltage having a desired voltage value. Each of the plurality of step-down chopper circuits steps down the DC voltage output from the voltage conversion circuit to a desired voltage and applies it to the corresponding LED light source (first LED light source 31 and second LED light source 32). On the circuit board 51, components of a voltage conversion circuit and a plurality of step-down chopper circuits are mounted. The circuit board 51 is arranged such that the mounting region of the remaining step-down chopper circuit is arranged between the mounting region of the voltage conversion circuit and the mounting region of the step-down chopper circuit having the largest maximum current among the plurality of step-down chopper circuits. Component placement is set.

  This places another step-down chopper circuit mounting area between the mounting area of the step-down chopper circuit with the largest maximum current and the mounting area of the voltage conversion circuit. Can be placed. Therefore, since the temperature rise of a circuit component can be suppressed, the lifetime of a circuit component can be extended and the lifetime of the power supply device 2 can be extended.

  The lighting device 1 of the present embodiment includes a plurality of LED light sources (first LED light sources) connected to the power supply device 2 and a plurality of step-down chopper circuits (first step-down chopper circuit 22 and second step-down chopper circuit 23). 31, the second LED light source 32) and the instrument main body 11. The instrument body 11 holds a plurality of LED light sources.

  Since this lighting device 1 includes the power supply device 2 described above, the temperature rise of the circuit components constituting the power supply device 2 is suppressed, and the life of the circuit components can be extended. Therefore, the long-life lighting device 1 is realized. be able to.

  In the illumination device 1 of the present embodiment, the plurality of LED light sources (the first LED light source 31 and the second LED light source 32) may be configured such that the color temperatures of the emitted colors are different from each other.

  In general, light emitting diodes tend to have lower luminous efficiency as the color temperature of the emitted color is lower. When a plurality of LED light sources having different color temperatures of the emitted color are lit with the same brightness, the color temperature is A low LED light source needs to pass a larger current than an LED light source having a high color temperature. Accordingly, a larger current flows through the step-down chopper circuit that applies a voltage to the LED light source having a low color temperature than the step-down chopper circuit that applies a voltage to the LED light source having a high color temperature, and the amount of heat generation is also increased. In such an illuminating device 1, the component arrangement is set so that the remaining step-down chopper circuit mounting area is arranged between the step-down chopper circuit mounting area having the largest maximum current and the voltage conversion circuit mounting area. Therefore, the temperature rise of circuit components can be suppressed. Therefore, the lifetime of the circuit components is extended, and the long-life lighting device 1 can be realized.

  In the present embodiment, the first LED light source 31 and the second LED light source 32 have the same color temperature, and the number of light emitting diodes LD1 constituting the first LED light source 31 and the second LED light source 32 are configured. The number of light emitting diodes LD2 may be different from the number of light emitting diodes LD2. If the number of the light emitting diodes LD2 constituting the second LED light source 32 is larger than the number of the light emitting diodes LD1 constituting the first LED light source 31, the second LED light source 32 is more than the voltage applied to the first LED light source 31. The applied voltage is larger. Therefore, the second step-down chopper circuit 23 that applies voltage to the second LED light source 32 has a larger maximum current than the first step-down chopper circuit 22 that applies voltage to the first LED light source 31, and the first step-down chopper circuit 22. The second step-down chopper circuit 23 generates more heat than the second step-down chopper circuit 23. Here, in the circuit board 51, the components are arranged such that the mounting region of the first step-down chopper circuit 22 is arranged between the mounting region of the second step-down chopper circuit 23 having the largest maximum current and the mounting region of the step-up chopper circuit 21. The arrangement is set. Therefore, since the mounting region of the first step-down chopper circuit 22 is disposed between the mounting region of the second step-down chopper circuit 23 having the largest maximum current and the mounting region of the step-up chopper circuit 21, the circuit having a large amount of heat generation. Parts can be placed apart. Therefore, since the temperature rise of a circuit component can be suppressed, the lifetime of a circuit component becomes long and the lifetime of the power supply device 2 can be lengthened.

  In the circuit example of FIG. 1, the power supply device 2 includes two step-down chopper circuits (first step-down chopper circuit 22 and second step-down chopper circuit 23). However, the number of step-down chopper circuits is not limited to two. Three or more may be used according to the number of LED light sources.

  FIG. 7 is a circuit diagram of the lighting device 1 when the power supply device 2 includes three step-down chopper circuits (a first step-down chopper circuit 22, a second step-down chopper circuit 23, and a third step-down chopper circuit 24). In addition, the same code | symbol is attached | subjected to the component which is common in the circuit of FIG. 1, and the description is abbreviate | omitted.

  The light source unit 3 includes a first LED light source 31 connected between the terminals P21 and P22, a second LED light source 32 connected between the terminals P21 and P23, and a third LED light source 33 connected between the terminals P21 and P24. Prepare. In the present embodiment, the first LED light source 31, the second LED light source 32, and the third LED light source 33 have different color temperatures of emitted colors. The first LED light source 31 includes a plurality of (for example, 72) light emitting diodes LD1 whose emission color is daylight color (color temperature is about 6000 K). The plurality of light emitting diodes LD1 are connected in series between the terminal P21 and the terminal P22 in a direction in which a current flows from the terminal P21 to the terminal P22. The second LED light source 32 includes a plurality of (for example, 72) light emitting diodes LD2 whose emission color is a light bulb color (color temperature is about 3000K). The plurality of light emitting diodes LD2 are connected in series between the terminal P21 and the terminal P23 in a direction in which a current flows from the terminal P21 to the terminal P23. The third LED light source 33 includes a plurality of (for example, 72) light emitting diodes LD3 whose emission color is white (color temperature is about 4000K). The plurality of light emitting diodes LD3 are connected in series between the terminal P21 and the terminal P24 in a direction in which a current flows from the terminal P21 to the terminal P24.

  The power supply device 2 includes a rectifier circuit 20, a step-up chopper circuit 21, a first step-down chopper circuit 22, a second step-down chopper circuit 23, a third step-down chopper circuit 24, a first control circuit 25, and a second control. Circuit 26. Since the circuit other than the third step-down chopper circuit 24 is the same as the circuit shown in FIG. 1, the description other than the third step-down chopper circuit 24 is omitted.

  The third step-down chopper circuit 24 includes a diode D4, a smoothing capacitor C4, a choke coil L4, a switching element Q4, and resistors R41 to R43. A series circuit of a smoothing capacitor C4, a choke coil L4, and a switching element Q4 is connected between the output terminals of the boost chopper circuit 21 (between both ends of the smoothing capacitor C1). The cathode of the diode D4 is connected to the output terminal on the high potential side of the boost chopper circuit 21, and the anode of the diode D4 is connected to the connection point between the choke coil L4 and the switching element Q4. Both ends of the smoothing capacitor C4 are connected to output terminals P11 and P14. The output terminal P11 is electrically connected to the terminal P21 of the light source unit 3 through an electric wire, and the output terminal P14 is electrically connected to the terminal P24 of the light source unit 3 through an electric wire, and between the both ends of the smoothing capacitor C4. In addition, the third LED light source 33 is electrically connected. A discharging resistor R41 is connected between both ends of the smoothing capacitor C4. A series circuit of resistors R42 and R43 is connected in parallel with the series circuit of the choke coil L4 and the switching element Q4, and the voltage V43 across the resistor R43 is input to the second control circuit 26. The drive signal VQ4 is input from the second control circuit 26 to the drive electrode of the switching element Q4, and on / off of the switching element Q4 is controlled by the second control circuit 26. The switching element Q4 is repeatedly turned on / off at a high frequency (about 50 kHz), so that the third step-down chopper circuit 24 performs a step-down operation. That is, the second control circuit 26 controls the output voltage V3 of the third step-down chopper circuit 24, whereby the light output of the third LED light source 33 is controlled.

  As described above, a light emitting diode having a low color temperature tends to have lower light emission efficiency than a light emitting diode having a high color temperature. Therefore, the light emission efficiency of the light emitting diode LD1 constituting the first LED light source 31 having a daylight white emission color is the highest, and the light emission efficiency of the light emitting diode LD2 constituting the second LED light source 32 having a light emission color of the light bulb color is the lowest. The light emission efficiency of the light emitting diode LD3 constituting the third LED light source 33 having a white emission color is lower than the light emission efficiency of the light emitting diode LD1 constituting the first LED light source 31, and the light emission efficiency of the light emitting diode LD2 constituting the second LED light source 32. Higher than.

  Therefore, in order to obtain the same level of light output by the first LED light source 31, the second LED light source 32, and the third LED light source 33, a larger current than the first LED light source 31 is caused to flow to the third LED light source 33. More current needs to flow through the second LED light source 32. Therefore, the maximum current of the third step-down chopper circuit 24 is larger than the maximum current of the first step-down chopper circuit 22, and the maximum current of the second step-down chopper circuit 23 is larger than the maximum current of the third step-down chopper circuit 24. Becomes larger. Therefore, it is expected that the heat generated by the choke coil L4, the switching element Q4, and the diode D4 of the third step-down chopper circuit 24 is larger than the heat generated by the choke coil L2, the switching element Q2, and the diode D2 of the first step-down chopper circuit 22. The Further, it is expected that the heat generated by the choke coil L3, the switching element Q3, and the diode D3 of the second step-down chopper circuit 23 is larger than the heat generated by the choke coil L4, the switching element Q4, and the diode D4 of the third step-down chopper circuit 24. The Further, since the step-up chopper circuit 21 supplies power to the first to third step-down chopper circuits 22 to 24, the step-up chopper circuit 21 includes the first step-down chopper circuit 22, the second step-down chopper circuit 23, and the third step-down chopper circuit 23. There is a possibility that a larger current flows than the step-down chopper circuit 24. Therefore, the heat generated by the choke coil L1, the switching element Q1, and the diode D1 of the step-up chopper circuit 21 may be larger than the heat generated by the first step-down chopper circuit 22, the second step-down chopper circuit 23, and the third step-down chopper circuit 24. is there.

  FIG. 8 is a diagram schematically showing mounting regions of the step-up chopper circuit 21, the first step-down chopper circuit 22, the second step-down chopper circuit 23, and the third step-down chopper circuit 24 on the circuit board 51. In FIG. 8, illustration of circuit components is omitted, and only the mounting area of each circuit is shown by a dotted line.

  In the circuit board 51, the mounting region of the step-up chopper circuit 21, the mounting region of the first step-down chopper circuit 22, the mounting region of the third step-down chopper circuit 24, and the mounting region of the second step-down chopper circuit 23 are shown in FIG. The component arrangement is designed so that they are arranged in order from the left side to the right side. Therefore, in the circuit board 51, the first step-down chopper circuit 22 to 24 has a first current between the mounting region of the second step-down chopper circuit 23 having the largest maximum current and the mounting region of the step-up chopper circuit 21. The mounting region of the third step-down chopper circuits 22 and 24 is arranged. Further, the components are arranged so that the mounting region of the first step-down chopper circuit 22 having the smallest maximum current among the first to third step-down chopper circuits 22 to 24 is mounted at a position closest to the mounting region of the step-up chopper circuit 21. Is designed.

  Accordingly, the mounting region of the second step-down chopper circuit 23 having the maximum maximum current among the first to third step-down chopper circuits 22 to 24 and the mounting region of the step-up chopper circuit 21 are adjacent to each other. Since components with large heat generation can be arranged apart and the temperature rise of circuit components can be suppressed, the long-life power supply device 2 and lighting device 1 can be realized.

  When four or more step-down chopper circuits are provided, the remaining step-down chopper circuit mounting region is provided between the mounting region of the step-down chopper circuit having the largest maximum current and the mounting region of the step-up chopper circuit 21 on the circuit board 51. It is only necessary that the component arrangement is designed so as to be arranged. Further, the component arrangement may be designed so that the mounting region of the step-down chopper circuit having the smallest maximum current is mounted at a position closest to the mounting region of the step-up chopper circuit 21. Note that the mounting region of the remaining step-down chopper circuit can be changed as appropriate, and the step-down chopper circuit having a smaller maximum current may be arranged closer to the mounting region of the step-up chopper circuit 21.

  As described above, the power supply device 2 of the present embodiment may include three or more step-down chopper circuits (for example, the first step-down chopper circuit 22, the second step-down chopper circuit 23, and the third step-down chopper circuit 24). In the circuit board 51, the mounting region of the step-down chopper circuit (first step-down chopper circuit 22) having the smallest maximum current among the plurality of step-down chopper circuits is adjacent to the mounting region of the voltage conversion circuit (step-up chopper circuit 21). The component arrangement may be set so as to be arranged. The step-down chopper circuit mounting area with the smallest maximum current is placed next to the voltage conversion circuit mounting area, so the step-down chopper circuit mounting area with the larger maximum current is placed next to the voltage conversion circuit mounting area. As compared with the case where the temperature is increased, the temperature rise of the circuit components can be suppressed, and the lifetime of the circuit components can be extended to realize the long-life power supply device 2 and the lighting device 1.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Power supply device 3 Light source unit 11 Instrument main body 21 Boost chopper circuit (voltage conversion circuit)
22 First step-down chopper circuit (step-down chopper circuit)
23 Second step-down chopper circuit (step-down chopper circuit)
24 Third step-down chopper circuit (step-down chopper circuit)
31 First LED light source (LED light source)
32 Second LED light source (LED light source)
33 Third LED light source (LED light source)
51 Circuit board

Claims (4)

A voltage conversion circuit that converts the input voltage into a DC voltage of a desired voltage value;
A plurality of step-down chopper circuits that step down the DC voltage output from the voltage conversion circuit to a desired voltage and apply it to the corresponding LED light source;
A circuit board on which components of the voltage conversion circuit and the plurality of step-down chopper circuits are mounted;
In the circuit board, the mounting region of the remaining step-down chopper circuit is disposed between the mounting region of the step-down chopper circuit in which the maximum current is the largest among the plurality of step-down chopper circuits and the mounting region of the voltage conversion circuit. A power supply device characterized in that the component arrangement is set to be Comprising three or more step-down chopper circuits,
The component placement of the circuit board is set such that a mounting region of the step-down chopper circuit having the smallest maximum current among the plurality of step-down chopper circuits is disposed next to the mounting region of the voltage conversion circuit. The power supply device according to claim 1. The power supply device according to claim 1 or 2,
A plurality of LED light sources connected to each of the plurality of step-down chopper circuits;
An illuminating device comprising: an instrument body that holds the plurality of LED light sources.   The lighting device according to claim 3, wherein the plurality of LED light sources are configured to have different color temperatures of emitted colors.

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