JP2019213300A - Power supply device and lighting device - Google Patents

Abstract

To provide a power supply device capable of stably driving a switching element even if a driving voltage of the switching element is higher than an operation voltage supplied to a control circuit.SOLUTION: A power supply device 10 includes a converter circuit 3, a drive circuit 5, a control circuit 4, a first control power supply circuit 81, and a second control power supply circuit 82. The converter circuit 3 includes a switching element Q1. The drive circuit 5 applies a drive voltage Vg1 to the switching element Q1. The control circuit 4 operates at an operation voltage V4 lower than the drive voltage Vg1, and controls the drive circuit 5. The first control power supply circuit 81 generates the drive voltage Vg1 and supplies the generated drive voltage Vg1 to the drive circuit 5. The second control power supply circuit 82 generates the operation voltage V4 of the control circuit 4, and supplies the generated operation voltage V4 to the control circuit 4. The second control power supply circuit 82 supplies the operation voltage V4 to the control circuit 4 after the first control power supply circuit 81 starts supplying the drive voltage Vg1 to the drive circuit 5.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a power supply device and a lighting device, and more particularly to a power supply device and a lighting device including a converter circuit including a switching element.

  Patent Document 1 discloses a lighting device that turns on a light source. The lighting device described in Patent Literature 1 includes a DC-DC converter circuit and a control circuit. The DC-DC converter circuit has a switching element. The switching element is switched by the control circuit. By this switching, the DC voltage input to the DC-DC converter circuit is converted into an output voltage, and the converted output voltage is output to the light source.

JP-A-2018-63898

  By the way, it may be required to use a high-breakdown-voltage switching element as the switching element.

  However, in the lighting device described in Patent Literature 1, when a high-breakdown-voltage switching element is used as the switching element, the drive voltage of the switching element may be higher than the lower limit voltage of the operating voltage range of the control circuit. In this case, the control circuit starts when an operating voltage equal to or higher than the lower limit voltage of the operating voltage range is supplied, and starts to apply a driving voltage to the switching element. However, immediately after the control circuit is activated, the drive voltage applied from the control circuit to the switching element may not reach the required voltage. In this case, there is a problem that the switching element cannot be driven stably.

  The present disclosure has been made in view of the above problems, and provides a power supply device and a lighting device that can stably drive a switching element even when the driving voltage of the switching element is higher than the operating voltage of the control circuit. The purpose is to provide.

  A power supply device according to an aspect of the present disclosure includes a converter circuit, a drive circuit, a control circuit, a first control power supply circuit, and a second control power supply circuit. The converter circuit includes a switching element. The switching element is driven with a driving voltage. The converter circuit converts a first DC voltage into a second DC voltage by switching of the switching element, and outputs the converted second DC voltage to a load. The drive circuit applies the drive voltage to the switching element. The control circuit operates at an operating voltage lower than the drive voltage, and controls the drive circuit. The first control power circuit generates the drive voltage and supplies the generated drive voltage to the drive circuit. The second control power supply circuit generates the operating voltage and supplies the generated operating voltage to the control circuit. The second control power supply circuit supplies the operation voltage to the control circuit after the first control power supply circuit starts to supply the drive voltage to the drive circuit.

  A lighting device according to an aspect of the present disclosure includes the power supply device and the load. The load is a light emitting unit, a light emitting drive circuit, or a constant current control circuit. The light emission drive circuit causes the light emitting unit to emit light. The constant voltage control circuit controls the output current of the converter circuit to be constant.

  According to the present disclosure, the switching element can be stably driven even when the driving voltage of the switching element is higher than the operating voltage of the control circuit.

FIG. 1 is a circuit diagram of the illumination device according to the embodiment. FIG. 2 is a comparison diagram comparing the time change of the charging voltage of the capacitor C3 (that is, the driving voltage supplied to the driving circuit) and the time change of the charging voltage of the capacitor C4 (that is, the operating voltage supplied to the control circuit). It is. FIG. 3A is a circuit diagram showing a modification of the load of the illumination device. FIG. 3B is a circuit diagram showing another modification of the load of the illumination device of the above.

  The embodiment described below is only one of various embodiments of the present disclosure. Embodiments of the present disclosure are not limited to the following embodiments, and may include other embodiments. In addition, the following embodiments can be variously changed according to the design or the like as long as they do not depart from the technical idea according to the present disclosure.

(Embodiment)
(1) Configuration The lighting device according to the present embodiment will be described below with reference to FIG.

  The lighting device 1 according to the present embodiment is a device that lights up the light emitting unit 200 using an AC voltage from the AC power supply 100. The lighting device 1 includes a pair of connection terminals t1 and t2 for connecting the AC power supply 100 and a pair of connection terminals t3 and t4 for connecting the light emitting unit 200. The connection terminals t1, t2, t3, and t4 may be components (terminals) for connecting electric wires or the like, or may be a part of a conductor formed as a lead on an electronic component or a circuit board, for example.

  The lighting device 1 is used, for example, for a stadium projector (lighting fixture). The electrical equipment installed in the stadium may be driven by a 400V class AC power source. In addition, the use of the illuminating device 1 is not limited to the projector for stadiums, and may be another luminaire. The use of the lighting device 1 may be, for example, a tunnel lamp installed in a tunnel or a projector used outside a stadium.

  In the lighting device 1, an AC power supply 100 with a standard voltage (nominal voltage) of 400 V class is connected between the pair of connection terminals t1 and t2. Here, the standard voltage of the AC power supply 100 is, for example, 415 V, 420 V, 440 V, or 460 V, but the voltage value of the AC voltage supplied from the AC power supply 100 varies within a predetermined voltage fluctuation range with respect to the standard voltage. May be. From the above, the AC power supply 100 is a power supply with a standard voltage of 400 V or more. Note that the AC power supply 100 is preferably a power supply having a standard voltage of 400V to 600V. Further, the light emitting unit 200 is electrically connected between the pair of connection terminals t3 and t4. The light emitting unit 200 is a light source and includes a plurality (two in the illustrated example) of light emitting diodes 201 electrically connected in series. Note that the number of light emitting diodes 201 is not limited to two and may be three or more.

  The lighting device 1 includes a power supply device 10 and a light emitting unit 200. The power supply device 10 is a device that steps down the AC voltage supplied from the AC power source 100 to a required DC voltage and lights the light emitting unit 200 using the reduced DC voltage. The required DC voltage is a DC voltage suitable for the light emitting unit 200 (for example, a rated voltage of the light emitting unit 200). The power supply device 10 includes a filter circuit 9, a rectifying / smoothing circuit 2, an insulated DC-DC converter circuit (hereinafter referred to as “converter circuit”) 3, a control circuit 4, a drive circuit 5, A circuit 8 and a constant voltage control circuit 11 are provided.

  The filter circuit 9 is a circuit that removes noise included in the AC voltage supplied from the AC power supply 100. The pair of input terminals of the filter circuit 9 are electrically connected to the pair of connection terminals t1 and t2, respectively.

  The rectifying / smoothing circuit 2 is a circuit that rectifies and smoothes the AC voltage from which noise has been removed by the filter circuit 9. The rectifying / smoothing circuit 2 includes a rectifying circuit DB1 and a smoothing capacitor C1.

  The rectification circuit DB1 rectifies the AC voltage input from the filter circuit 9 (for example, full-wave rectification), and outputs the rectified voltage V1 to the smoothing capacitor C1. The rectifier circuit DB1 is, for example, a diode bridge composed of four diodes. The pair of input terminals of the rectifier circuit DB1 are electrically connected to the pair of output terminals of the filter circuit 9, respectively. The smoothing capacitor C1 smoothes the voltage V1 rectified by the rectifier circuit DB1 and outputs the smoothed voltage (DC voltage) V2 to the converter circuit 3. The voltage V2 becomes the output voltage of the rectifying / smoothing circuit 2. The smoothing capacitor C1 is electrically connected across the pair of output terminals of the rectifier circuit DB1.

  The converter circuit 3 includes a switching element Q1, and converts the voltage V2 (first DC voltage) rectified and smoothed by the rectifying and smoothing circuit 2 into an output voltage V3 (second DC voltage) by switching the switching element Q1. Then, the converter circuit 3 outputs the converted output voltage V3 to the light emitting unit 200 (load) as the required DC voltage. The converter circuit 3 is, for example, a flyback converter circuit.

  The converter circuit 3 includes a pair of input terminals t11 and t12, a pair of output terminals t13 and t14, a transformer T1, a switching element Q1, a resistance element R2, and a rectifying and smoothing circuit 31.

  The pair of input terminals t11 and t12 are electrically connected to the pair of output terminals of the rectifying and smoothing circuit 2, respectively. The pair of output terminals t13 and t14 are electrically connected to the pair of connection terminals t3 and t4, respectively. The input terminals t11 and t12 and the output terminals t13 and t14 may be components (terminals) for connecting electric wires or the like, or may be, for example, electronic component leads or part of a conductor formed as wiring on a circuit board. .

  The transformer T1 electrically connects an input side (also referred to as a primary side) to which the rectifying and smoothing circuit 2 is electrically connected and an output side (also referred to as a secondary side) to which the light emitting unit 200 is electrically connected. It is equipment that insulates. The transformer T1 is a device that transforms (for example, steps down) the output voltage V2 of the rectifying and smoothing circuit 2 to the required DC voltage. The transformer T1 is, for example, an insulating flyback transformer.

  The transformer T1 includes a primary winding n1 and a secondary winding n2, and electrically insulates between the pair of input terminals t11 and t12 and the pair of output terminals t13 and t14. The primary winding n1 is energized with a current corresponding to the output voltage V2 (first DC voltage) of the rectifying and smoothing circuit 2 and turned on and off by switching of the switching element Q1. The secondary winding n2 is configured to generate an induced electromotive force having a voltage suitable for the light emitting unit 200 (for example, a rated voltage of the light emitting unit 200) by switching of the switching element Q1.

  The transformer T1 further includes a primary side auxiliary winding n11 (another winding) and a secondary side auxiliary winding n21. The primary side auxiliary winding n11 is provided on the primary side of the transformer T1 separately from the primary winding n1. The primary side auxiliary winding n11 is configured to generate an induced electromotive force having a voltage lower than the output voltage V2 (first DC voltage) of the rectifying and smoothing circuit 2 by switching of the switching element Q1. For example, the number of turns of the primary side auxiliary winding n11 is set to be smaller than the number of turns of the primary winding n1. The secondary side auxiliary winding n21 is provided on the secondary side of the transformer T1 separately from the secondary winding n2. The secondary auxiliary winding n21 is configured to generate an induced electromotive force having a voltage necessary for the operation of the constant voltage control circuit 11 by switching of the switching element Q1.

  The primary winding n1, the switching element Q1, and the resistance element R2 of the transformer T1 are electrically connected between the pair of input terminals t11 and t12 while being connected in series with each other.

  The switching element Q1 is a switching element that performs chopper control (that is, turns on and off the flow of DC current) of the DC current that is the output current I2 of the rectifying and smoothing circuit 2 by switching according to the drive voltage Vg1 from the drive circuit 5. . By the switching of the switching element Q1, induced electromotive force is generated in the secondary winding n2, the primary side auxiliary winding n11, and the secondary side auxiliary winding n21 of the transformer T1, respectively. The switching element Q1 is, for example, an n-channel enhancement type MOSFET (Metal Oxide Semiconductor Field Effect Transistor). More specifically, the switching element Q1 is a switching element that is driven with a drive voltage Vg1 that is higher than the operating voltage V4 of the control circuit 4, and is, for example, a SiC (silicon carbide) -MOSFET.

  The driving voltage Vg1 of the switching element Q1 is a voltage within a driving voltage range (for example, 18 V or more) that can drive the switching element Q1. In the present embodiment, a first threshold voltage (for example, 18.6 V) is applied to the switching element Q1 as the drive voltage Vg1 of the switching element Q1. The operating voltage V4 of the control circuit 4 is a voltage within an operating voltage range (for example, 10V to 26V) in which the control circuit 4 can be operated. In the present embodiment, a voltage of a second threshold voltage (for example, 16.8 V) is supplied to the control circuit 4 as the operating voltage V4 of the control circuit 4. Therefore, the drive voltage Vg1 of the switching element Q1 is higher than the operating voltage V4 of the control circuit 4.

  The switching element Q1 has two main electrodes (for example, a drain and a source) and a control electrode (for example, a gate). Hereinafter, of the two main electrodes, one main electrode is a drain, the other main electrode is a source, and a control electrode is a gate. The drain of the switching element Q1 is electrically connected to one end of the primary winding n1 of the transformer T1, the source of the switching element Q1 is electrically connected to the resistance element R2, and the gate of the switching element Q1 is a drive circuit. 5 is electrically connected.

  The rectifying and smoothing circuit 31 is a circuit that rectifies and smoothes the induced electromotive force generated in the secondary winding n2 of the transformer T1, and outputs the rectified and smoothed voltage from the output terminals t13 and t14 as the output voltage V3. The rectifying / smoothing circuit 31 is provided between the secondary winding n2 of the transformer T1 and the pair of output terminals t13 and t14. The rectifying / smoothing circuit 31 includes a diode D1 and a smoothing capacitor C2.

  The diode D1 and the smoothing capacitor C2 are electrically connected between both ends of the secondary winding n2 of the transformer T1 while being connected in series with each other. The cathode of the diode D1 is electrically connected to the smoothing capacitor C2, and the anode of the diode D1 is electrically connected to one end of the secondary winding n2. The smoothing capacitor C2 is electrically connected across the output terminals t13 and t14.

  In the converter circuit 3, the output current I2 of the rectifying / smoothing circuit 2 is chopper-controlled by switching of the switching element Q1. As a result, a voltage (inductive electromotive force) corresponding to the turn ratio between the primary winding n1 and the secondary winding n2 is generated between both ends of the secondary winding n2 of the transformer T1. Further, a voltage (induced electromotive force) corresponding to the turn ratio between the primary winding n1 and the primary auxiliary winding n11 is generated between both ends of the primary auxiliary winding n11 of the transformer T1. A voltage (inductive electromotive force) corresponding to the turn ratio between the primary winding n1 and the secondary auxiliary winding n21 is generated between both ends of the secondary auxiliary winding n21 of the transformer T1.

  Although the converter circuit 3 of the present embodiment is a flyback converter circuit, the converter circuit 3 is not limited to the above circuit configuration, and the primary side and the secondary side of the transformer T1 are electrically insulated. Such a circuit configuration can be changed as appropriate.

  The drive circuit 5 is a circuit that applies the drive voltage Vg1 to the switching element Q1 under the control of the control circuit 4. The drive circuit 5 applies the drive voltage Vg1 to the gate of the switching element Q1 when switching the switching element Q1 from off to on, and drives the gate of the switching element Q1 when switching the switching element Q1 from on to off. The application of the voltage Vg1 is released. That is, the drive voltage Vg1 of the switching element Q1 is an on voltage for switching the switching element Q1 from off to on. The drive circuit 5 includes switching elements Q7, Q8 and resistance elements R15, R16, R17, R18.

  The switching element Q7 is, for example, an npn bipolar transistor. The switching element Q8 is a pnp bipolar transistor, for example. Each of the switching elements Q7 and Q8 has two main electrodes (for example, a collector and an emitter) and a control electrode (for example, a base). Hereinafter, of the two main electrodes, one main electrode is used as a collector, the other main electrode is used as an emitter, and the control electrode is used as a base.

  The resistance element R15, the switching element Q7, the switching element Q8, and the resistance element R17 form a series circuit that is electrically connected in series in this order. This series circuit is electrically connected between the high-potential-side end of a later-described capacitor C3 of the control power supply circuit 8 and the input terminal t12. One end of the resistor element R15 is electrically connected to one end of the capacitor C3, and one end of the resistor element R17 is electrically connected to the input terminal t12.

  The emitters of the switching elements Q7 and Q8 are electrically connected to each other. The collector of the switching element Q7 is electrically connected to the capacitor C3 via the resistance element R15. The collector of the switching element Q8 is electrically connected to the input terminal t12 via the resistance element R17. The connection point of the switching elements Q7 and Q8 is electrically connected to the gate of the switching element Q1. The bases of the switching elements Q7 and Q8 are electrically connected to each other, and are electrically connected to the control terminal P1 of the control circuit 4 via the resistance element R16. A resistance element R18 is electrically connected between a connection point between the resistance element R16 and the control terminal P1 and a connection point between the resistance element R17 and the input terminal t12.

  The control power supply circuit 8 is a circuit that supplies the operation voltage V4 to the control circuit 4 and supplies the drive voltage Vg1 of the switching element Q1 to the drive circuit 5. The control power supply circuit 8 includes resistance elements R1 and R3, diodes D3 and D4, a first control power supply circuit 81, and a second control power supply circuit 82.

  The first control power supply circuit 81 is a circuit that generates the drive voltage Vg1 of the switching element Q1 and supplies the generated drive voltage Vg1 to the drive circuit 5. The first control power supply circuit 81 generates the drive voltage Vg1 using the output voltage V2 (first DC voltage) of the rectifying and smoothing circuit 2 before starting the converter circuit 3. Further, the first control power supply circuit 81 generates the drive voltage Vg1 using the voltage V5 generated in the primary side auxiliary winding n11 (another winding) during the operation of the converter circuit 3.

  During the operation of the converter circuit 3, not only the voltage V5 generated in the primary side auxiliary winding n11 but also the output voltage V2 of the rectifying and smoothing circuit 2 is input to the first control power supply circuit 81. However, during the operation of the converter circuit 3, the supply of the output voltage V <b> 2 of the rectifying and smoothing circuit 2 to the converter circuit 3 is more dominant than the supply to the first control power supply circuit 81. As a result, during the operation of the converter circuit 3, the first control power supply circuit 81 generates the drive voltage Vg1 substantially using only the voltage V5 due to the dielectric electromotive force of the primary side auxiliary winding n11.

  The first control power circuit 81 includes a capacitor C3, and outputs the charging voltage VC3 of the capacitor C3 as the driving voltage Vg1 of the switching element Q1. More specifically, the charging voltage VC3 when the voltage is equal to or higher than the first threshold voltage is the driving voltage Vg1. The capacitor C3 is electrically connected between a later-described ground terminal P4 of the control circuit 4 and a resistance element R15 of the drive circuit 5.

  The end on the high potential side of the capacitor C3 is electrically connected to the output terminal on the high potential side of the rectifying and smoothing circuit 2 via the diode D3 and the resistance element R1. Further, the end portion on the high potential side of the capacitor C3 is electrically connected to one end portion of the primary auxiliary winding n11 of the converter circuit 3 via the diode D4 and the resistance element R3. Thereby, the capacitor C3 is charged by the output voltage of the rectifying / smoothing circuit 2 before the converter circuit 3 is started. Further, during the operation of the converter circuit 3, the capacitor C <b> 3 is charged by a combined voltage obtained by adding the voltage V <b> 5 generated in the primary side auxiliary winding n <b> 11 and the output voltage V <b> 2 of the rectifying and smoothing circuit 2 in parallel.

  The end of the capacitor C3 on the high potential side is electrically connected to a power input terminal P3 (described later) of the control circuit 4 via switching elements Q5 and Q2 (described later) of the second control power circuit 82. An end portion on the low potential side of the capacitor C3 is electrically connected to a later-described ground terminal P4 of the control circuit 4.

  The second control power supply circuit 82 is a circuit that generates the operating voltage V4 of the control circuit 4 and supplies the generated operating voltage V4 to the control circuit 4. The second control power supply circuit 82 operates on the control circuit 4 after the first control power supply circuit 81 starts supplying the drive voltage Vg1 of the switching element Q1 having a voltage higher than the operation voltage V4 of the control circuit 4 to the drive circuit 5. A voltage V4 is supplied. The second control power circuit 82 generates the operating voltage V4 from the drive voltage Vg1 generated by the first control power circuit 81. The second control power supply circuit 82 includes an input circuit 821 and a constant voltage circuit 822.

  The input circuit 821 receives the drive voltage Vg1 generated by the first control power supply circuit 81. The input circuit 821 does not output the generated voltage to the constant voltage circuit 822 when the voltage generated by the first control power supply circuit 81 (that is, the charging voltage VC3 of the capacitor C3) is less than the first threshold voltage. When the generated voltage is equal to or higher than the first threshold voltage, the input circuit 821 outputs the generated voltage to the constant voltage circuit 822 as the drive voltage Vg1. The input circuit 821 includes a breakdown diode (also referred to as a Zener diode) ZD3, resistance elements R11, R12, R13, and R14, switching elements Q4, Q5, and Q6, and a capacitor C6.

  Each of the switching elements Q4, Q5, Q6, and Q2 is, for example, an npn-type bipolar transistor. Each of the switching elements Q4, Q5, Q6, and Q2 has two main electrodes (for example, a collector and an emitter) and a control electrode (for example, a base). Hereinafter, of the two main electrodes, one main electrode is used as a collector, the other main electrode is used as an emitter, and the control electrode is used as a base.

  The resistor element R11, the breakdown diode ZD3, and the resistor element R12 are electrically connected in series with each other, and are electrically connected between both ends of the capacitor C3. The cathode of the breakdown diode ZD3 is electrically connected to the high potential end of the capacitor C3 via the resistor element R11, and the anode of the breakdown diode ZD3 is connected to the low potential side of the capacitor C3 via the resistor element R12. It is electrically connected to the end of the. The capacitor C6 is electrically connected in parallel to the resistance element R12.

  The breakdown diode ZD3 is switched on or off according to the charging voltage VC3 of the capacitor C3. The breakdown diode ZD3 is turned on when the breakdown diode ZD3 is turned on, and the breakdown diode ZD3 is turned off when the breakdown diode ZD3 is cut off. More specifically, the breakdown voltage of the breakdown diode ZD3 is set to the same voltage as the first threshold voltage (for example, 18.6V), and when the charging voltage VC3 of the capacitor C3 becomes equal to or higher than the first threshold voltage, the breakdown diode ZD3 Switches from off to on.

  The resistance element R13 and the switching element Q4 are electrically connected in series with each other, and are electrically connected in series between both ends of the capacitor C3. The collector of the switching element Q4 is electrically connected to the high potential end of the capacitor C3 via the resistance element R13, and the emitter of the switching element Q4 is electrically connected to the low potential end of the capacitor C3. Has been. The base of the switching element Q3 is electrically connected to the connection point between the breakdown diode ZD3 and the resistance element R12. The switching element Q4 is switched on or off in accordance with the on / off of the breakdown diode ZD3. That is, when the breakdown diode ZD3 is on, the switching element Q4 is on, and when the breakdown diode ZD3 is off, the switching element Q4 is off.

  The switching element Q5 is electrically connected between the high potential end of the capacitor C3 and the power input terminal P3 of the control circuit 4. The collector of the switching element Q5 is electrically connected to the high potential end of the capacitor C3, and the emitter of the switching element Q5 is connected between the power input terminal P3 of the control circuit 4 via the switching element Q2. Electrically connected. The base of the switching element Q5 is electrically connected to the end on the low potential side of the capacitor C3 via the switching element. Resistance element R14 is electrically connected between the collector and base of switching element Q5. The switching element Q5 is switched off or on according to the on or off of the switching element Q6. That is, when the switching element Q6 is on, the switching element Q5 is off, and when the switching element Q6 is off, the switching element Q5 is on. Switching element Q5, in its ON state, outputs the output current of capacitor C3 to constant voltage circuit 822 and outputs charging voltage VC3 of capacitor C3 to switching element Q2.

  The switching element Q6 is electrically connected between the base of the switching element Q5 and the low potential side end of the capacitor C3. The collector of the switching element Q6 is electrically connected to the base of the switching element Q5, and the emitter of the switching element Q6 is electrically connected to the low potential side end of the capacitor C3. The base of the switching element Q6 is electrically connected to the collector of the switching element Q4. The switching element Q6 is switched off or on according to the on or off of the switching element Q4. That is, when the switching element Q4 is on, the switching element Q6 is off, and when the switching element Q4 is off, the switching element Q5 is on.

  The constant voltage circuit 822 generates an operation voltage V4 of the control circuit 4 from the drive voltage Vg1 output from the input circuit 821, and operates so that the generated operation voltage V4 becomes constant in accordance with, for example, the second threshold voltage. It is a circuit that controls the voltage V4 and outputs it to the control circuit 4. The constant voltage circuit 822 includes a breakdown diode ZD1, a resistance element R4, a switching element Q2, and a capacitor C4.

  The switching element Q2 is electrically connected between the switching element Q5 and the power input terminal P3 of the control circuit 4. The emitter of the switching element Q2 is electrically connected to the power input terminal P3 of the control circuit 4, and the collector of the switching element Q2 is electrically connected to the emitter of the switching element Q5. The base of the switching element Q2 is electrically connected to the ground terminal P4 of the control circuit 4 via the breakdown diode ZD1. The cathode of the breakdown diode ZD1 is electrically connected to the base of the switching element Q2, and the anode of the breakdown diode ZD1 is electrically connected to the ground terminal P4 of the control circuit 4. The resistance element R4 is electrically connected between the collector and base of the switching element Q2. The capacitor C4 is electrically connected between the power input terminal P3 and the ground terminal P4 of the control circuit 4.

  The switching element Q2 is turned off or on according to the on or off of the breakdown diode ZD1. That is, when the breakdown diode ZD1 is on, the switching element Q2 is off, and when the breakdown diode ZD1 is off, the switching element Q2 is on. Then, in the ON state of the switching element Q2, the conduction current of the switching element Q5 (that is, the charge of the capacitor C3) is output to the capacitor C4. Capacitor C4 is charged by the current that has passed through switching element Q2. The charging voltage VC4 of the capacitor C4 is output to the power input terminal P3 as the operating voltage V4 of the control circuit 4.

  The breakdown diode ZD1 is switched on or off according to the charging voltage VC4 of the capacitor C4. More specifically, the breakdown voltage of the breakdown diode ZD1 is set to the same voltage as the second threshold voltage (for example, 16.8V). Thereby, when the charging voltage VC4 of the capacitor C4 becomes equal to or higher than the second threshold voltage, the breakdown diode ZD1 is turned on. As a result, the switching element Q2 is turned off, and charging of the capacitor C4 is stopped. When the charging voltage VC4 of the capacitor C4 becomes less than the operating voltage V4 of the control circuit 4, the breakdown diode ZD1 is turned off, the switching element Q2 is turned on, and the capacitor C4 is charged. In this way, the charging voltage VC4 of the capacitor C4 is controlled so as to be consistent with the second threshold voltage.

  The constant voltage control circuit 11 is a circuit for controlling the output voltage V3 of the converter circuit 3 to be constant. The constant voltage control circuit 11 detects whether or not the output voltage V3 of the converter circuit 3 is equal to or higher than the threshold voltage, and feeds back the detection result to the control circuit 4. The constant voltage control circuit 11 includes resistance elements R7, R8, R9, R10, a photocoupler PC1, a three-terminal regulator IC2, and a constant voltage circuit 111.

  The three-terminal regulator IC2 is a shunt regulator, for example, and has two main electrodes (for example, a cathode and an anode) and a control electrode. The three-terminal regulator IC2 conducts (i.e., turns on) between the two main electrodes when a voltage equal to or higher than the threshold voltage is input to the control electrode, and two voltages when the voltage less than the threshold voltage is input to the control electrode. It is an element that blocks (that is, turns off) between main electrodes. Hereinafter, of the two main electrodes of the three-terminal regulator IC2, one main electrode is an anode and the other main electrode is a cathode.

  The resistance element R9 and the resistance element R10 are electrically connected in series with each other, and are electrically connected between the output terminal t13 and the three-terminal regulator IC2. The resistor element R7, the resistor element R8, and the three-terminal regulator IC2 are electrically connected in series with each other, and are electrically connected between a switching element Q3 (described later) of the constant voltage circuit 111 and the resistor element R10. Yes. The cathode of the three-terminal regulator IC2 is electrically connected to the emitter of the switching element Q3 (that is, the output terminal of the constant voltage circuit 111) via the resistance elements R8 and R7. The anode of the three-terminal regulator IC2 is electrically connected to the output terminal t13 via the resistance elements R10 and R9. The control electrode of the three-terminal regulator IC2 is electrically connected to the connection point of the resistance elements R9 and R10. Resistor elements R9 and R10 constitute a voltage dividing circuit that divides output voltage V3 of converter circuit 3 and applies it to the control electrode of three-terminal regulator IC2.

  The photocoupler PC1 includes a light emitting diode D6 as a light emitting element and a phototransistor Q9 as a light receiving element. The light emitting diode D6 is electrically connected in parallel to the resistance element R8. The cathode of the light emitting diode D6 is electrically connected to the connection point between the resistance element R8 and the three-terminal regulator IC2, and the anode of the light emitting diode D6 is electrically connected to the connection point between the resistance elements R8 and R7. The phototransistor Q9 is electrically connected between the detection terminal P2 of the control circuit 4 and the ground terminal P4.

  The three-terminal regulator IC2 is turned on depending on whether or not a voltage equal to or higher than the voltage (corresponding voltage) corresponding to the threshold voltage with respect to the output voltage V3 of the converter circuit 3 is input to the control electrode of the three-terminal regulator IC2. Or it switches off and conducts in the reverse direction in the on state. Due to the conduction of the three-terminal regulator IC2, the current I6 from the constant voltage circuit 111 flows to the light emitting diode D6 of the photocoupler PC1. Thereby, the light emitting diode D6 emits light, and the light emitting diode D6 of the photocoupler PC1 is turned on by the light. As a result, a low level signal is input to the detection terminal P2 of the control circuit 4. In the off state of the three-terminal regulator IC2, the light-emitting diode D6 is not energized, so the phototransistor Q9 is turned off, and a high level signal (a signal having a higher voltage than the low level signal) is input to the detection terminal P2 of the control circuit 4. Is done. That is, the control circuit 4 is informed whether the output voltage V3 of the converter circuit 3 is equal to or higher than the threshold voltage depending on whether the signal output to the detection terminal P2 is a low level signal.

  The constant voltage circuit 111 generates the operating voltage V6 of the constant voltage control circuit 11 from the voltage (inductive electromotive force) generated in the secondary side auxiliary winding n21 of the transformer T1. The operating voltage V6 of the constant voltage control circuit 11 is a voltage for operating the constant voltage control circuit 11. The constant voltage circuit 111 includes resistance elements R5 and R6, a diode D5, a capacitor C5, a switching element Q3, and a breakdown diode ZD2.

  The switching element Q3 is, for example, an npn bipolar transistor. The switching element Q3 has two main electrodes (for example, a collector and an emitter) and a control electrode (for example, a base). Hereinafter, of the two main electrodes of the switching element Q3, one main electrode is used as a collector, the other main electrode is used as an emitter, and the control electrode is used as a base.

  The resistance element R5, the diode D5, and the switching element Q3 are electrically connected to each other in series, and are electrically connected between one end of the secondary auxiliary winding n21 and the resistance element R7. The cathode of the diode D5 is electrically connected to the collector of the switching element Q3, and the anode of the diode D5 is electrically connected to one end of the secondary auxiliary winding n21 via the resistance element R5. The base of the switching element Q3 is electrically connected to the other end of the secondary side auxiliary winding n21 via the breakdown diode ZD2. The emitter of the switching element Q3 is electrically connected to the resistance element R7, and the collector of the switching element Q3 is electrically connected to the cathode of the diode D5. The cathode of the breakdown diode ZD2 is electrically connected to the base of the switching element Q3, and the anode of the breakdown diode ZD2 is electrically connected to the other end of the secondary auxiliary winding n21. Resistance element R6 is electrically connected between the collector and base of switching element Q3. The capacitor C5 is electrically connected to the collector of the switching element Q3 and the cathode of the breakdown diode ZD2.

  The capacitor C5 is charged by the induced electromotive force generated in the secondary side auxiliary winding n21. The breakdown diode ZD2 is turned on or off depending on whether or not the charging voltage VC5 of the capacitor C5 is equal to or higher than a predetermined voltage necessary for the operation of the constant voltage control circuit 11. The switching element Q3 is switched off or on according to whether the breakdown diode ZD2 is on or off. The on / off of the switching element Q3 controls the induced electromotive force generated in the secondary side auxiliary winding n21 so as to coincide with the predetermined voltage, and outputs the operating voltage V6 from the switching element Q3 to the resistance element R7 side. Is done. Further, a current I6 corresponding to the output operating voltage V6 is output from the switching element Q3 to the resistance element R7.

  The control circuit 4 operates by receiving the operation voltage V4 lower than the drive voltage Vg1 from the second control power supply circuit 82, and controls the drive circuit 5. The control circuit 4 controls the switching element Q1 via the drive circuit 5. The control circuit 4 is configured as a control IC (Integrated Circuit) composed of “FA5601” manufactured by Fuji Electric Co., Ltd., for example. The control circuit 4 includes a control terminal P1, a detection terminal P2, a power input terminal P3, and a ground terminal P4.

  The control terminal P <b> 1 is a terminal that outputs a control signal for controlling the drive circuit 5 to the drive circuit 5. The control terminal P1 is electrically connected to the connection point of the bases of the switching elements Q7 and Q8 via the resistance element R16. The control circuit 4 outputs a high level signal or a low level signal as a control signal from the control terminal P1.

  When a high level signal is output from the control terminal P1, in the drive circuit 5, the switching element Q7 is turned on and the switching element Q8 is turned off. As a result, the drive voltage Vg1 from the first control power supply circuit 81 is applied to the gate of the switching element Q1, and the switching element Q1 is turned on. On the other hand, when a low level signal is output from the control terminal P1, in the drive circuit 5, the switching element Q7 is turned off and the switching element Q8 is turned on. As a result, the application of the drive voltage Vg1 to the gate of the switching element Q1 is released, and the switching element Q1 is turned off.

  The control circuit 4 outputs, for example, a PWM signal subjected to PWM (Pulse Width Modulation) control as the control signal. The on time of the PWM signal becomes a high level signal, and the off time becomes a low level signal. That is, the control circuit 4 controls the switching element Q1 by PWM control. In the present embodiment, the control circuit 4 performs PWM control of the switching element Q1, but the control method of the switching element Q1 is not limited to PWM, and other control methods such as PFM (Pulse Frequency Modulation) control are adopted. May be.

  The detection terminal P2 is electrically connected to the ground terminal P4 via the phototransistor Q9 of the photocoupler PC1. A low level signal or a high level signal is input to the detection terminal P2 depending on whether the phototransistor Q9 is on or off. That is, when the phototransistor Q9 is on, a low level signal is input to the detection terminal P2, and when the phototransistor Q9 is off, a high level signal is input to the detection terminal P2. The control circuit 4 determines whether or not the output voltage V3 of the converter circuit 3 is equal to or higher than the third threshold voltage depending on whether a low level signal or a high level signal is input to the detection terminal P2. . That is, when the low level signal is input to the detection terminal P2, the control circuit 4 determines that the output voltage V3 of the converter circuit 3 is equal to or higher than the third threshold voltage. Further, when a high level signal is input to the detection terminal P2, the control circuit 4 determines that the output voltage V3 of the converter circuit 3 is less than the third threshold voltage. The third threshold voltage is a voltage suitable for driving the light emitting unit 200, for example. Based on the determination result, the control circuit 4 controls the switching element Q1 so that the output voltage V3 of the converter circuit 3 matches the third threshold voltage. Thereby, the output voltage V3 of the converter circuit 3 is controlled to be constant.

  More specifically, when it is determined that the output voltage V3 of the converter circuit 3 is equal to or higher than the third threshold voltage, the control circuit 4 controls the switching element Q1 so that the output voltage V3 of the converter circuit 3 decreases. . Further, when the control circuit 4 determines that the output voltage V3 of the converter circuit 3 is lower than the third threshold voltage, the control circuit 4 controls the switching element Q1 so that the output voltage V3 of the converter circuit 3 increases.

  The power input terminal P3 is a terminal to which the operating voltage V4 generated by the second control power circuit 82 is input. When a voltage within the operating voltage range (for example, 10 V to 26 V) of the control circuit 4 is input to the power input terminal P3, the control circuit 4 is activated and starts controlling the switching element Q1 via the drive circuit 5. .

  The ground terminal P <b> 4 is grounded and is a terminal for ensuring grounding in the power supply device 10.

(2) Operation The operation of the lighting device 1 will be described with reference to FIG.

  When an AC voltage is supplied from the AC power supply 100 to the lighting device 1, the output voltage V2 of the rectifying and smoothing circuit 2 is applied to the capacitor C3 of the first control power supply circuit 81 via the resistor element R1 and the diode D3, and the capacitor C3 is charged.

  When the charging voltage VC3 of the capacitor C3 is less than a first threshold voltage (for example, 18.6V), the charging voltage VC3 is not output to the power input terminal P3 of the control circuit 4 via the second control power circuit 82. More specifically, in this case (that is, when charging voltage VC3 is less than the first threshold voltage), breakdown diode ZD3 is turned off in input circuit 821 of second control power supply circuit 82. As a result, switching element Q4 is turned off, current is input to the gate of switching element Q6, and switching element Q6 is turned on. Thereby, no current is input to the base of the switching element Q5, and the switching element Q5 is turned off. Therefore, the input circuit 821 does not output the charging voltage VC3 to the constant voltage circuit 822. Accordingly, the charging voltage VC3 is not output to the power input terminal P3 of the control circuit 4 via the second control power circuit 82. Therefore, in this case, the operating voltage V4 is not input to the power input terminal P3 of the control circuit 4, and the control circuit 4 does not start.

  On the other hand, when the charging voltage VC3 becomes equal to or higher than the first threshold voltage, the charging voltage VC3 equal to or higher than the first threshold voltage is started to be output (that is, supplied) from the first control power supply circuit 81 to the driving circuit 5 as the driving voltage Vg1. . That is, the drive voltage Vg1 starts to be output from the first control power supply circuit 81 to the drive circuit 5. Further, when the charging voltage VC3 becomes equal to or higher than the first threshold voltage, the second control power circuit 82 generates the operating voltage V4 of the control circuit 4 from the charging voltage VC3, and the generated operating voltage V4 is the power input of the control circuit 4 Input to terminal P3.

  More specifically, when the charging voltage VC3 is equal to or higher than the first threshold voltage, the breakdown diode ZD3 is turned on in the input circuit 821 of the second control power supply circuit 82. As a result, a current is input to the base of the switching element Q4, and the switching element Q4 is turned on. Thereby, no current is input to the gate of the switching element Q6, and the switching element Q6 is turned off. Thereby, a current is input to the base of the switching element Q5, and the switching element Q5 is turned on. As a result, the input circuit 821 outputs the charging voltage VC3 to the constant voltage circuit 822. Further, the output current I2 of the rectifying / smoothing circuit 2 flows to the switching element Q2 via the resistance element R1, the diode D3, and the switching element Q5. Further, the discharge current of the capacitor C3 also flows to the switching element Q2 via the switching element Q5. Due to these currents, the constant voltage circuit 822 charges the capacitor C4, and the charging voltage VC4 of the capacitor C4 increases.

  When the charging voltage VC4 of the capacitor C4 becomes equal to or higher than the lower limit voltage of the operating voltage range of the control circuit 4, the voltage input to the power input terminal P3 becomes higher than the lower limit voltage, and the voltage higher than the lower limit voltage is The operation voltage V4 is input to the power input terminal P3. As described above, when the time from when the drive voltage Vg1 is started to be supplied to the drive circuit 5 until the charging voltage VC4 of the capacitor C4 reaches the lower limit voltage has elapsed, the operation voltage V4 is supplied to the control circuit 4. Supply is started. That is, after the drive voltage Vg1 is supplied to the drive circuit 5, the operation voltage V4 is supplied to the control circuit 4. With this supply start, the control circuit 4 starts to control the drive circuit 5 so as to apply the drive voltage Vg1 to the switching element Q1.

  Then, when the charging voltage VC4 further increases and becomes equal to or higher than the second threshold voltage, the breakdown diode ZD1 is turned on, the switching element Q2 is turned off, and charging of the capacitor C4 is stopped. When the charging voltage VC4 becomes lower than the second threshold voltage, the breakdown diode ZD1 is turned off, the switching element Q2 is turned on, and charging of the capacitor C4 is resumed.

  As described above, in the lighting device 1, the driving voltage of the switching element Q <b> 1 (that is, the driving voltage equal to or higher than the first threshold voltage and higher than the operating voltage V <b> 4 of the control circuit 4) Vg <b> 1 is supplied to the driving circuit 5. After being started, the operating voltage V4 of the control circuit 4 is supplied to the control circuit 4. Therefore, immediately after the control circuit 4 is started, the drive voltage Vg1 higher than the operating voltage V4 of the control circuit 4 can be applied to the switching element Q1, and the switching element Q1 can be driven stably.

  Then, as described above, when the operating voltage V4 (that is, the voltage within the operating voltage range) is input to the power input terminal P3, the control circuit 4 is activated and the switching circuit Q1 is driven so that the switching circuit Q1 is driven. Begin to control. The drive circuit 5 applies the drive voltage (drive voltage equal to or higher than the first threshold voltage) Vg1 supplied from the first control power supply circuit 81 to the control electrode of the switching element Q1 under the control of the control circuit 4. Thereby, switching element Q1 is stably switched.

  By switching of the switching element Q1, a voltage (induced electromotive force) is generated between both ends of the secondary winding n2 of the transformer T1, and the generated voltage is rectified and smoothed by the rectifying and smoothing circuit 31. The rectified and smoothed voltage is output to the light emitting unit 200 from the output terminals t13 and t14 as the output voltage V3. As a result, the light emitting unit 200 is turned on.

  Further, a voltage (inductive electromotive force) V5 is generated between both ends of the primary auxiliary winding n11 of the transformer T1 by switching of the switching element Q1. As a result, in addition to the output voltage V2 from the rectifying / smoothing circuit 2, the capacitor C3 is also charged by the voltage V5 due to the induced electromotive force in the primary side auxiliary winding n11. During the operation of the converter circuit 3, the supply of the output voltage V <b> 2 of the rectifying / smoothing circuit 2 to the converter circuit 3 is more dominant than the supply to the first control power supply circuit 81. As a result, during the operation of the converter circuit 3, the first control power supply circuit 81 substantially operates only by the voltage V5 due to the dielectric electromotive force of the primary side auxiliary winding n11 (that is, generates the drive voltage Vg1). That is, before starting the converter circuit 3, the first control power supply circuit 81 generates the drive voltage Vg1 of the switching element Q1 using the output voltage V2 of the rectifying and smoothing circuit 2. During the operation of the converter circuit 3, the first control power supply circuit 81 generates the drive voltage Vg1 of the switching element Q1 using the voltage V5 generated by the induced electromotive force generated in the primary side auxiliary winding n11.

  The voltage V5 due to the induced electromotive force generated in the primary side auxiliary winding n11 is lower than the output voltage V2 of the rectifying and smoothing circuit 2. For this reason, during the operation of the converter circuit 3, a voltage V5 lower than the output voltage V2 of the rectifying and smoothing circuit 2 is applied to the control power supply circuit 8 (particularly the first control power supply circuit 81). Therefore, it is possible to reduce the application of the output voltage (that is, a relatively high voltage) V2 of the rectifying / smoothing circuit 2 to the control power supply circuit 8.

  Further, a voltage (inductive electromotive force) is generated between both ends of the secondary side auxiliary winding n21 of the transformer T1 by switching of the switching element Q1. This voltage is controlled to coincide with a predetermined voltage within the operating voltage range of the constant voltage control circuit 11 and is supplied to the constant voltage control circuit 11. With this supply, the constant voltage control circuit 11 operates. That is, in the constant voltage control circuit 11, when the output voltage V3 of the converter circuit 3 is less than the third threshold voltage, a voltage less than the reference voltage is applied to the control electrode of the three-terminal regulator IC2, and the three-terminal regulator IC2 is turned off. It becomes a state. Accordingly, the light emitting diode D6 of the constant voltage control circuit 11 is not energized (that is, does not emit light), and the phototransistor Q9 is turned off. As a result, a high level signal is input to the detection terminal P2 of the control circuit 4. On the other hand, when the output voltage V3 of the converter circuit 3 becomes equal to or higher than the third threshold voltage, a voltage higher than the reference voltage is applied to the control electrode of the three-terminal regulator IC2, and the three-terminal regulator IC2 is turned on. As a result, the light emitting diode D6 conducts and emits light, and the phototransistor Q9 is turned on by the light. As a result, a low level signal is input to the detection terminal P2 of the control circuit 4. Note that the third threshold voltage is a voltage suitable for driving the light emitting unit 200.

  The control circuit 4 determines whether or not the output voltage V3 of the converter circuit 3 is equal to or higher than the third threshold voltage according to the input signal to the detection terminal P2. That is, when a high level signal is input to the detection terminal P2, it is determined that the output voltage V3 of the converter circuit 3 is lower than the third threshold voltage, and the driving is performed so that the output voltage V3 of the converter circuit 3 increases. The switching element Q1 is controlled via the circuit 5. On the other hand, when a low level signal is input to the detection terminal P2, the control circuit 4 determines that the output voltage V3 of the converter circuit 3 is equal to or higher than the third threshold voltage, and the output voltage V3 of the converter circuit 3 is reduced. Thus, the switching element Q1 is controlled via the drive circuit 5. Thereby, the output voltage V3 of the converter circuit 3 (that is, the output voltage of the power supply device 10) is controlled so as to coincide with the third threshold voltage.

  FIG. 2 shows the time change of the charging voltage VC3 of the capacitor C3 (that is, the driving voltage Vg1 supplied to the driving circuit 5) and the time change of the charging voltage VC4 of the capacitor C4 (that is, the operating voltage V4 supplied to the control circuit 4). FIG.

  As can be seen from FIG. 2, the charging voltage VC3 of the capacitor C3 starts to be charged from the time τ0 and reaches the first threshold voltage Va1 (18.6V) at the time τ1. The charging voltage VC4 of the capacitor C4 starts to be charged from the time τ1 when the charging voltage VC3 of the capacitor C3 reaches the first threshold voltage Va1, reaches the lower limit voltage Vc1 of the operating voltage range at the time τ2, and reaches the lower limit voltage Vc1 at the time τ3. 2 The threshold voltage Vb1 (16.8V) is reached. At time τ2 when the charging voltage VC4 of the capacitor C4 reaches the lower limit voltage Vc1, the charging voltage VC3 of the capacitor C3 reaches the first threshold voltage Va1.

  From the above, after the drive voltage Vg1 higher than the first threshold voltage Va1 (that is, the voltage higher than the operating voltage V4 of the control circuit 4) Vg1 is started to be supplied to the drive circuit 5 (for example, after the time τ1), the control circuit 4 It can be seen that the operation voltage V4 (for example, VC1) is started to be supplied to the control circuit 4. Therefore, immediately after the start of the control circuit 4 (time τ2), the drive voltage Vg1 higher than the operating voltage V4 of the control circuit 4 can be applied to the switching element Q1, and the switching element Q1 can be driven stably.

  As described above, according to the lighting device 1 and the power supply device 10 according to this embodiment, the second control power supply circuit 82 is such that the first control power supply circuit 81 has the drive voltage Vg1 higher than the operating voltage V4 of the control circuit 4. After the supply to the drive circuit 5 is started, the operating voltage V4 of the control circuit 4 is supplied to the control circuit 4. Therefore, immediately after the control circuit 4 is started, a driving voltage higher than the operating voltage of the control circuit 4 can be applied to the switching element Q1, and the switching element Q1 can be driven stably. Further, by using the first control power supply circuit 81 and the second control power supply circuit 82, a general-purpose control IC (for example, “FA5601” manufactured by Fuji Electric Co., Ltd.) can be used as the control circuit 4.

(Modification)
Below, the illuminating device which concerns on the modification of the said embodiment is listed. In addition, each structure of the modified example demonstrated below is applicable in combination with each structure demonstrated in the said embodiment suitably.

  In the above embodiment, the light emitting unit 200 is provided as a load of the power supply device 10, but the load of the power supply device 10 is not limited to the light emitting unit 200. As illustrated in FIG. 3A, a drive circuit 90 (light emission drive circuit) that drives the light emitting unit 91 may be provided as a load of the power supply device 10. In this case, a load (for example, the light emitting unit 91) driven by the drive circuit 90 is provided at the subsequent stage of the drive circuit 90. The light emitting unit 91 includes a plurality (two in the illustrated example) of light emitting diodes. Note that the number of light emitting diodes in the light emitting unit 91 is not limited to two, and may be three or more.

  Further, as shown in FIG. 3B, a constant current control circuit 93 for controlling the output current I3 of the converter circuit 3 to be constant may be provided as a load of the power supply device 10. In this case, a load (for example, the light emitting unit 94) that is driven by the current that is current-controlled by the constant current control circuit 93 is provided after the constant current control circuit 93. The light emitting unit 94 includes a plurality (two in the illustrated example) of light emitting diodes. Note that the number of light emitting diodes in the light emitting section 94 is not limited to two and may be three or more.

  In the above embodiment, a constant current control circuit for controlling the output current I3 of the converter circuit 3 to be constant may be provided instead of the constant voltage control circuit 11.

  In the above-described embodiment, the light emitting unit 200 is provided as a load of the power supply device 10, but the load of the power supply device 10 is not limited to the light emitting unit 200. The load of the power supply device 10 may be any electrical device that can be driven by a DC voltage.

(Summary)
As described above, the power supply device (10) according to the first aspect includes the converter circuit (3), the drive circuit (5), the control circuit (4), the first control power supply circuit (81), A second control power circuit (82). The converter circuit (3) includes a switching element (Q1). The switching element (Q1) is driven by the drive voltage (Vg1). The converter circuit (3) converts the first DC voltage (V2) into the second DC voltage (V3) by switching the switching element (Q1), and outputs the converted second DC voltage (V3) to the load (200). To do. The drive circuit (5) applies a drive voltage (Vg1) to the switching element (Q1). The control circuit (4) operates at an operating voltage (V4) lower than the driving voltage (Vg1), and controls the driving circuit (5). The first control power circuit (81) generates a drive voltage (Vg1) and supplies the generated drive voltage (Vg1) to the drive circuit (5). The second control power circuit (82) generates the operating voltage (V4) of the control circuit (4) and supplies the generated operating voltage (V4) to the control circuit (4). The second control power circuit (82) supplies the operating voltage (V4) to the control circuit (4) after the first control power circuit (81) starts supplying the driving voltage (Vg1) to the driving circuit (5). .

  According to this configuration, the second control power supply circuit (82) is configured such that the first control power supply circuit (81) generates a drive voltage (Vg1) higher than the operation voltage (V4) of the control circuit (4). After starting the supply to (5), the operating voltage (V4) of the control circuit (4) is supplied to the control circuit (4). Therefore, immediately after the start of the control circuit (4), a drive voltage (Vg1) higher than the operating voltage (V4) of the control circuit (4) can be applied to the switching element (Q1), and the switching element (Q1) It can be driven stably.

  In the power supply device (10) according to the second aspect, in the first aspect, the second control power supply circuit (82) generates a control circuit (Vg1) from the drive voltage (Vg1) generated by the first control power supply circuit (81). The operation voltage (V4) of 4) is generated.

  According to this configuration, a dedicated power supply for generating the operating voltage (V4) of the control circuit (4) can be omitted.

  In the power supply device (10) according to the third aspect, in the second aspect, the second control power supply circuit (82) includes an input circuit (821) and a constant voltage circuit (822). The input circuit (821) receives the drive voltage (Vg1) generated by the first control power supply circuit (81). The constant voltage circuit (822) controls the operating voltage (V4) output to the control circuit (4) to be constant. When the voltage (VC3) generated by the first control power supply circuit (81) is less than the threshold voltage (first threshold voltage), the generated voltage (VC3) is not output to the constant voltage circuit (822). When the voltage (VC3) generated by the first control power circuit (81) is equal to or higher than the threshold voltage, the input circuit (821) uses the generated voltage (VC3) as the drive voltage (Vg1). 822). The constant voltage circuit (822) generates the operating voltage (V4) of the control circuit (4) from the drive voltage (Vg1) output from the input circuit (821), and the generated operating voltage (V4) is constant. Control.

  According to this configuration, the input circuit (821) and the constant voltage circuit (822) can be configured with only basic circuit elements (transistors, capacitors, resistance elements, breakdown diodes, and the like), so the second control power circuit (82) can be configured with a simple circuit.

  In the power supply device (10) according to the fourth aspect, in any one of the first to third aspects, the converter circuit (3) includes a transformer (T1). The transformer (T1) includes a primary winding (n1) and a winding (primary auxiliary winding n11) different from the primary winding (n1). The primary winding (n1) is energized with a current corresponding to the first DC voltage (V2), which is turned on and off by switching of the switching element (Q1). In another winding (n11), an induced electromotive force having a voltage lower than that of the first DC voltage (V2) is generated by switching of the switching element (Q1). The first control power circuit (81) generates the drive voltage (Vg1) of the switching element (Q1) from the first DC voltage (V2) before starting the converter circuit (3). The first control power circuit (81) generates the drive voltage (Vg1) of the switching element (Q1) from the voltage (V5) generated in the other winding (n11) during the operation of the converter circuit (3).

  According to this configuration, when the converter circuit (3) is started, the first DC voltage (that is, a relatively high voltage) (V2) is applied to the first control power supply circuit (81). However, during the operation of the converter circuit (3), a voltage (V5) lower than the first DC voltage (V2) is applied to the first control power supply circuit (81). Therefore, it can reduce that the 1st DC voltage (V2) continues being applied to the 1st control power circuit (81).

  The illuminating device which concerns on a 5th aspect is provided with any one power supply device (10) and load (200, 90, 93) among the 1st-4th aspects. The load (200, 90, 93) is a light emitting unit (200), a light emitting drive circuit (90), or a constant current control circuit (93). The light emission drive circuit (90) drives the light emitting section (91). The constant current control circuit (93) controls the output current (I3) of the converter circuit (3) to be constant.

  According to this structure, the illuminating device (1) which has said effect can be provided.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Rectification smoothing circuit 3 Converter circuit 4 Control circuit 5 Drive circuit 10 Power supply device 81 1st control power supply circuit 82 2nd control power supply circuit 90 Drive circuit (drive circuit for light emission)
93 constant current control circuit 200 light emitting section 821 input circuit 822 constant voltage circuit I3 output current n1 primary winding n11 primary side auxiliary winding (another winding)
Q1 switching element V2, V3, V5 voltage VC3 charging voltage V4 operating voltage Vg1 driving voltage T1 transformer

Claims (5)

A converter circuit that includes a switching element that is driven by a driving voltage, converts the first DC voltage to a second DC voltage by switching the switching element, and outputs the converted second DC voltage to a load;
A drive circuit for applying the drive voltage to the switching element;
A control circuit that operates at an operating voltage lower than the drive voltage and controls the drive circuit;
A first control power supply circuit that generates the drive voltage and supplies the generated drive voltage to the drive circuit;
A second control power supply circuit that generates the operating voltage and supplies the generated operating voltage to the control circuit,
The second control power supply circuit is a power supply device that supplies the operation voltage to the control circuit after the first control power supply circuit starts supplying the drive voltage to the drive circuit. The power supply device according to claim 1, wherein the second control power supply circuit generates the operation voltage from the drive voltage generated by the first control power supply circuit. The second control power circuit is
An input circuit for receiving the drive voltage generated by the first control power supply circuit;
A constant voltage circuit for controlling the operating voltage output to the control circuit to be constant,
When the voltage generated by the first control power circuit is less than a threshold voltage, the input circuit does not output the generated voltage to the constant voltage circuit, and the voltage generated by the first control power circuit Is equal to or higher than the threshold voltage, the generated voltage is output to the constant voltage circuit as the drive voltage,
The power supply device according to claim 2, wherein the constant voltage circuit generates the operating voltage from the drive voltage output from the input circuit, and controls the generated operating voltage to be constant. The converter circuit includes a transformer having a primary winding and a winding different from the primary winding,
The primary winding is energized with a current corresponding to the first DC voltage, which is turned on and off by switching of the switching element,
In the another winding, an induced electromotive force lower than the first DC voltage is generated by switching of the switching element,
The first control power supply circuit generates the drive voltage from the first DC voltage before starting the converter circuit, and the drive voltage from the voltage generated in the other winding during the operation of the converter circuit. The power supply device according to any one of claims 1 to 3. The power supply device according to any one of claims 1 to 4,
Including the load,
The load is a light emitting unit, a light emission drive circuit that causes the light emitting unit to emit light, or a constant current control circuit that controls the output current of the converter circuit to be constant.

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