JP2015210974A - Lighting device and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device and an illumination device, capable of obtaining a simple circuit and good circuit efficiency.SOLUTION: According to an embodiment, there is provided a lighting device comprising a first and a second chopper circuits, a first and a second driving circuits, a first and a second secondary windings, and a first switch unit and a control unit. The first chopper circuit includes a first switching element and a first inductor, and converts an input voltage to a first DC voltage. The second chopper circuit includes a second switching element and a second inductor, and converts a first DC voltage to a second DC voltage. The first secondary winding is magnetically coupled to the first inductor, and generates a first driving voltage. The second secondary winding is magnetically coupled to the second inductor, and generates a second driving voltage. The first switch unit switches a supply state and a non-supply state of the first driving voltage. The control unit controls switching of the first switch unit according to at least one of the first driving voltage and the second driving voltage.

Description

  Embodiments described herein relate generally to a lighting device and a lighting device.

  There is a lighting device used in connection with an illumination load having a light source such as an LED. There is a lighting device including a lighting load and a lighting device. The lighting device converts power supplied from a commercial power source or the like into power corresponding to the lighting load, and supplies the converted power to the lighting load. Thereby, a lighting device lights the light source of illumination load. In such lighting devices and lighting devices, it is desired to obtain good circuit efficiency with a simple circuit.

JP 2012-33611 A

  Embodiments of the present invention provide a lighting device and a lighting device with a simple circuit and good circuit efficiency.

  According to an embodiment of the present invention, a first chopper circuit, a second chopper circuit, a first drive circuit, a second drive circuit, a first secondary winding, a second secondary winding, There is provided a lighting device including one switch unit and a control unit. The first chopper circuit includes a first switching element and a first inductor, and converts an input voltage into a first DC voltage by switching of the first switching element. The second chopper circuit is electrically connected to the first chopper circuit and a lighting load, includes a second switching element and a second inductor, and the first DC voltage is generated by switching of the second switching element. It converts into a 2nd DC voltage, and outputs the said 2nd DC voltage to the said illumination load. The first drive circuit controls the switching of the first switching element. The second drive circuit controls the switching of the second switching element. The first secondary winding is magnetically coupled to the first inductor, and generates a first drive voltage corresponding to a current flowing through the first inductor. The second secondary winding is magnetically coupled to the second inductor, and generates a second drive voltage corresponding to a current flowing through the second inductor. The first switch unit switches between a supply state and a non-supply state of the first drive voltage. The control unit controls switching of the first switch unit according to at least one of the first drive voltage and the second drive voltage.

  A lighting device and a lighting device having a simple circuit and good circuit efficiency are provided.

It is a block diagram showing typically the lighting installation concerning a 1st embodiment. It is a table | surface showing an example of operation | movement of the lighting device which concerns on 1st Embodiment. It is a block diagram which represents typically the illuminating device which concerns on 2nd Embodiment.

Each embodiment will be described below with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones. Further, even when the same part is represented, the dimensions and ratios may be represented differently depending on the drawings.
Note that, in the present specification and each drawing, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

(First embodiment)
FIG. 1 is a block diagram schematically illustrating the illumination device according to the first embodiment.
As illustrated in FIG. 1, the lighting device 200 includes a lighting device 10 and a light source module 100.

  The lighting device 10 is connected to the AC power supply 4, for example. AC power is supplied from the AC power supply 4 to the lighting device 10. The AC power source 4 is, for example, a commercial power source. The AC power supply 4 may be a private power generator, for example. Note that the power supplied to the lighting device 10 may be DC power or the like. When the power supplied to the lighting device 10 is DC power, the rectifier circuit 32 described later is omitted. Hereinafter, a case where AC power is supplied to the lighting device 10 will be described as an example.

  In the present specification, “connection” means electrical connection, and includes cases where the connection is not physically connected or connection is made via other elements. In addition, the case of magnetic coupling through a transformer or the like is also included in “connection”.

  The lighting device 10 is electrically connected to the light source module 100. The lighting device 10 converts AC power supplied from the AC power supply 4 into DC power corresponding to the light source module 100 and supplies the converted DC power to the light source module 100. Thereby, the lighting device 10 lights the light source module 100.

  The light source module 100 includes an illumination load 102 and a connected part 104. The connected portion 104 is used for connection with the lighting device 10. The lighting load 102 includes a light source 106. The illumination load 102 includes a plurality of light sources 106, for example. In this example, the light sources 106 are connected in series. Each light source 106 may be connected in parallel, for example, or a combination of series connection and parallel connection may be used. The number of the light sources 106 may be arbitrary. For example, the number of the light sources 106 may be one.

  For example, a light emitting diode (LED) is used as the light source 106. The light source 106 may be, for example, an organic light emitting diode (OLED), an inorganic electroluminescent light emitting element, an organic electroluminescent light emitting element, or another electroluminescent light emitting element. Good. The light source 106 may be a light bulb, for example. Hereinafter, the light source 106 will be described as an LED.

  The lighting device 10 includes a main body portion 12 and a connection portion 14. The main body portion 12 is connected to the AC power source 4 and the connection portion 14. The connection unit 14 is used for electrical connection with the light source module 100. The connection unit 14 is connected to the connected unit 104 of the light source module 100. The connecting portion 14 is electrically connected to the connected portion 104 and obtains an electrical connection with the light source module 100.

  In this example, the light source module 100 is detachably connected to the lighting device 10 via the connecting portion 14 and the connected portion 104. The lighting device 10 is not limited to this, and may be directly connected to the light source module 100 by wiring or the like. Further, the lighting device 10 may be directly connected to the lighting load 102. The lighting device 10 should just be electrically connected with the illumination load 102 at least.

  The main body 12 includes a first chopper circuit 21, a second chopper circuit 22, a first drive circuit 23, a second drive circuit 24, a first secondary winding 25, and a second secondary winding 26. , A first switch unit 27, a second switch unit 28, a control unit 30, a filter circuit 31, a rectifier circuit 32, smoothing capacitors 33 and 34, and an output capacitor 35.

  The filter circuit 31 is electrically connected to the AC power supply 4. For example, the filter circuit 31 suppresses noise included in AC power supplied from the AC power supply 4.

  The rectifier circuit 32 is electrically connected to the filter circuit 31. The rectifier circuit 32 rectifies the AC voltage input via the filter circuit 31 and converts it into a rectified voltage. For the rectifier circuit 32, for example, a diode bridge in which four rectifier elements are combined is used. That is, the rectifier circuit 32 is a full wave rectifier. The rectified voltage is, for example, a pulsating voltage.

  The rectifier circuit 32 has a pair of input terminals 32a and 32b, a high potential output terminal 32c, and a low potential output terminal 32d. The input terminals 32a and 32b are electrically connected to the filter circuit 31. The rectifier circuit 32 converts an alternating voltage input via the input terminals 32a and 32b into a rectified voltage, and outputs the rectified voltage from the high potential output terminal 32c and the low potential output terminal 32d. The potential of the low potential output terminal 32d is set to a reference potential (for example, ground potential). The potential of the high potential output terminal 32c is set to a potential higher than the potential of the low potential output terminal 32d.

  The rectifier circuit 32 may be a half-wave rectifier or the like. The rectified voltage may be a full-wave rectified pulsating current or a half-wave rectified pulsating current. For the rectifier circuit 32, for example, a Schottky barrier diode is used. Thereby, for example, good responsiveness can be obtained.

  The smoothing capacitor 33 is connected between the output terminals 32 c and 32 d of the rectifier circuit 32. The smoothing capacitor 33 converts the rectified voltage into a DC voltage by smoothing the rectified voltage of the rectifier circuit 32.

  The smoothing capacitor 33 is connected to the first chopper circuit 21. The smoothing capacitor 33 inputs the converted DC voltage to the first chopper circuit 21. Thus, in this example, the DC voltage of the smoothing capacitor 33 is input to the first chopper circuit 21 as the input voltage. The input voltage input to the first chopper circuit 21 is not limited to a DC voltage, and may be an AC voltage, a rectified voltage, or the like.

  The first chopper circuit 21 includes a first switching element 41, a first inductor 42, and a first diode 43. The first chopper circuit 21 converts the input voltage into the first DC voltage by the switching of the first switching element 41.

  The first switching element 41 includes electrodes 41a to 41c. One end of the first inductor 42 is electrically connected to the high potential output terminal 32c. The other end of the first inductor 42 is electrically connected to the electrode 41a. The electrode 41b is electrically connected to the low potential output terminal 32d. The anode of the first diode 43 is electrically connected to the electrode 41a. The cathode of the first diode 43 is electrically connected to one end of the smoothing capacitor 34. The other end of the smoothing capacitor 34 is electrically connected to the low potential output terminal 32d.

  That is, in this example, the first chopper circuit 21 is a boost chopper circuit. In other words, the first chopper circuit 21 is a power factor correction circuit. The first chopper circuit 21 improves the power factor, for example, by switching the first switching element 41 and bringing the input current closer to a sine wave. The first chopper circuit 21 is not limited to the step-up chopper circuit, and may be a step-down chopper circuit.

  The first switching element 41 is, for example, an n-channel FET. For example, the electrode 41a is a drain, the electrode 41b is a source, and the electrode 41c is a gate. The first switching element 41 may be, for example, a p-channel FET or a bipolar transistor.

  The smoothing capacitor 34 smoothes the voltage that changes according to the switching of the first switching element 41 and generates a first DC voltage.

  The second chopper circuit 22 is electrically connected to the first chopper circuit 21 and the illumination load 102 of the light source module 100. In this example, the second chopper circuit 22 is electrically connected to the illumination load 102 via the connecting portion 14 and the connected portion 104.

  The second chopper circuit 22 includes a second switching element 45, a second diode 46, and a second inductor 47. The second chopper circuit 22 converts the first DC voltage into the second DC voltage by switching of the second switching element 45. Then, the second chopper circuit 22 outputs the second DC voltage toward the illumination load 102. The voltage actually input to the illumination load 102 may be a second DC voltage or a DC voltage obtained by further converting the second DC voltage.

  The second switching element 45 includes an electrode 45a, an electrode 45b, and an electrode 45c. The electrode 45 a is electrically connected to the cathode of the first diode 43. The electrode 45 b is electrically connected to the cathode of the second diode 46. The anode of the second diode 46 is electrically connected to the low potential output terminal 32d. One end of the second inductor 47 is electrically connected to the electrode 45b. The other end of the second inductor 47 is electrically connected to one end of the output capacitor 35.

  That is, in this example, the second chopper circuit 22 is a step-down chopper circuit. The second chopper circuit 22 is, for example, a constant current circuit. The second chopper circuit 22 converts the first DC voltage into a second DC voltage corresponding to the illumination load 102. The second chopper circuit 22 is not limited to the step-down chopper circuit but may be a step-up chopper circuit.

  The second switching element 45 is, for example, an n-channel FET. For example, the electrode 45a is a drain, the electrode 45b is a source, and the electrode 45c is a gate. For example, the second switching element 45 may be a p-channel FET or a bipolar transistor.

  The other end of the output capacitor 35 is electrically connected to the low potential output terminal 32d. The output capacitor 35 smoothes the voltage that changes according to the switching of the second switching element 45 and generates a second DC voltage.

  The first drive circuit 23 controls switching of the first switching element 41. The first drive circuit 23 is electrically connected to the electrode 41c. The first drive circuit 23 switches the first switching element 41 by inputting a signal to the electrode 41 c of the first switching element 41. The electrode 41c is a so-called control electrode.

  For example, the first drive circuit 23 converts the input voltage into a first DC voltage of about 410V. For example, the first drive circuit 23 changes the switching frequency of the first switching element 41 according to the input voltage. For example, the first drive circuit 23 generates a substantially constant first DC voltage regardless of the voltage value of the input voltage. For example, the first drive circuit 23 acquires the voltage value of the input voltage from the control unit 30 and changes the switching frequency of the first switching element 41 according to the acquired voltage value.

  The second drive circuit 24 controls the switching of the second switching element 45. The second drive circuit 24 is electrically connected to the electrode 45c. The second drive circuit 24 switches the second switching element 45 by inputting a signal to the electrode 45 c of the second switching element 45. The electrode 45c is a so-called control electrode. For example, the second drive circuit 24 converts a first DC voltage of about 410V into a second DC voltage of about 60V.

  The second drive circuit 24 generates a second DC voltage across the output capacitor 35 by switching the second switching element 45. Thereby, electric power is supplied from the second chopper circuit 22 to the light source module 100. And the 2nd drive circuit 24 stops supply of the electric power from the 2nd chopper circuit 22 to the light source module 100 by making the 2nd switching element 45 into an OFF state, for example.

  The first secondary winding 25 is magnetically coupled to the first inductor 42 and generates a first drive voltage VCC 1 corresponding to the current flowing through the first inductor 42. One end of the first secondary winding 25 is electrically connected to the low potential output terminal 32d. The other end of the first secondary winding 25 is electrically connected to the first switch unit 27 via a resistor 50 and a capacitor 51.

  The second secondary winding 26 is magnetically coupled to the second inductor 47 and generates a second drive voltage VCC 2 corresponding to the current flowing through the second inductor 47. One end of the second secondary winding 26 is electrically connected to the low potential output terminal 32d. The other end of the second secondary winding 26 is electrically connected to the second switch unit 28 via a resistor 52 and a capacitor 53.

  The first switch unit 27 switches between a supply state and a non-supply state of the first drive voltage VCC1. In this example, the first switch unit 27 includes the first secondary winding 25 and the first drive circuit 23, the first secondary winding 25 and the second drive circuit 24, and the first second Provided between the next winding 25 and the control unit 30. That is, the first switch unit 27 switches between a supply state and a non-supply state of the first drive voltage VCC1 to the first drive circuit 23, the second drive circuit 24, and the control unit 30.

  The second switch unit 28 switches between a supply state and a non-supply state of the second drive voltage VCC2. In this example, the second switch unit 28 includes the second secondary winding 26 and the first drive circuit 23, the second secondary winding 26 and the second drive circuit 24, and the second second Provided between the next winding 26 and the control unit 30. That is, the second switch unit 28 switches between a supply state and a non-supply state of the second drive voltage VCC2 to the first drive circuit 23, the second drive circuit 24, and the control unit 30.

  As described above, the first drive voltage VCC1 and the second drive voltage VCC2 are supplied to the first drive circuit 23, the second drive circuit 24, and the control unit 30, for example. The first drive circuit 23, the second drive circuit 24, and the control unit 30 operate by supplying at least one of the first drive voltage VCC1 and the second drive voltage VCC2. In this example, the first drive voltage VCC1 and the second drive voltage VCC2 are also supplied to the control unit 30. Without being limited thereto, the control unit 30 may be operated with a power source different from the first drive voltage VCC1 and the second drive voltage VCC2.

  The first drive voltage VCC1 and the second voltage VCC2 are, for example, 15V. For example, the second voltage VCC2 is substantially the same as the first drive voltage VCC1. The second voltage VCC2 may be different from the first drive voltage VCC1. The first drive voltage VCC1 and the second voltage VCC2 may be appropriately set according to the operating voltages of the first drive circuit 23, the second drive circuit 24, and the control unit 30, for example.

  The control unit 30 controls the switching of the first switch unit 27 according to the second drive voltage VCC2. In this example, the control unit 30 controls switching of the second switch unit 28 according to the second drive voltage VCC2.

  The first drive circuit 23, the second drive circuit 24, and the control unit 30 are, for example, independent control ICs. The first drive circuit 23, the second drive circuit 24, and the control unit 30 may be configured by, for example, a single integrated circuit on a single chip. The first drive circuit 23, the second drive circuit 24, and the control unit 30 may be logic blocks provided in one integrated circuit.

  The first switch unit 27 includes, for example, switching elements 60 and 61 and a resistor 62. The switching elements 60 and 61 are, for example, npn-type bipolar transistors. The switching elements 60 and 61 are not limited to this, and may be FETs.

  The collector of the switching element 60 is electrically connected to the capacitor 51. The emitter of the switching element 60 is electrically connected to the first drive circuit 23, the second drive circuit 24, and the control unit 30. The base of the switching element 60 is connected to the collector of the switching element 61. The emitter of the switching element 61 is set to a reference potential. The emitter of the switching element 61 is electrically connected to, for example, the low potential output terminal 32d. The base of the switching element 61 is electrically connected to the control unit 30 via a resistor. One end of the resistor 62 is electrically connected to the collector of the switching element 60. The other end of the resistor 62 is electrically connected to the base of the switching element 60.

  The control unit 30 switches the first switch unit 27 between the supply state and the non-supply state by switching the switching element 61 on and off. In this example, when the switching element 61 is in the off state, the switching element 60 is in the on state, and the first switch unit 27 is in the supply state. When the switching element 61 is on, the switching element 60 is off and the first switch unit 27 is not supplied.

  The second switch unit 28 includes, for example, switching elements 64 and 65 and a resistor 66. Since the configuration of the second switch unit 28 is substantially the same as the configuration of the first switch unit 27, detailed description thereof is omitted. The control unit 30 switches the second switch unit 28 between the supply state and the non-supply state by switching the switching element 65 on and off. The configuration of each of the switch units 27 and 28 is not limited to the above, and may be any configuration that can switch between a supply state and a non-supply state.

  The controller 30 detects the input voltage. In other words, the control unit 30 detects the power supply voltage of the AC power supply 4. The control unit 30 includes, for example, a resistor 70 electrically connected to the high potential output terminal 32c, a resistor 71 electrically connected to the resistor 70, a resistor 72 electrically connected to the resistor 71, and a resistor An input voltage is detected by a resistor 73 connected between 71 and a resistor 72. A voltage obtained by dividing the input voltage by the voltage dividing ratio of the resistors 70 to 73 is input to the control unit 30. The control unit 30 detects the input voltage based on this voltage.

  In addition, a dimming signal is input to the control unit 30 from, for example, an external wall switch. The light control signal is a signal indicating the brightness (light control level) of the light source module 100. The dimming signal is, for example, a PWM signal having a duty ratio corresponding to the dimming degree. The dimming signal may be, for example, an AC voltage whose conduction angle is controlled by a dimmer or the like. In this example, a dimming signal is input to the control unit 30 via the rectifier 75 and the photocoupler 76. In this example, the control unit 30 and the external signal source are electrically insulated from the photocoupler 76. Without being limited thereto, the control unit 30 may be electrically connected to an external signal source. The dimming signal may be input directly to the control unit 30 from an external signal source.

  The lighting device 10 further includes a feedback circuit 36. The feedback circuit 36 includes, for example, an operational amplifier 80, a current detection resistor 82, and resistors 83 and 84. The current detection resistor 82 is electrically connected between the low potential output terminal 32d and the low potential side terminal of the connection portion 14. In other words, the current detection resistor 82 is electrically connected between the low potential output terminal 32 d and the low potential side terminal of the output capacitor 35. Thereby, the current detection resistor 82 is used to detect the load current flowing through the illumination load 102.

  The operational amplifier 80 has a non-inverting input terminal, an inverting input terminal, and an output terminal. The inverting input terminal is connected to one end of the resistor 83 and one end of the resistor 84. The other end of the resistor 83 is electrically connected to the current detection resistor 82. The other end of the resistor 84 is electrically connected to the low potential output terminal 32d. As a result, a voltage corresponding to the load current is input to the inverting input terminal.

  The non-inverting input terminal is electrically connected to the control unit 30. A dimming signal is input from the control unit 30 to the non-inverting input terminal. For example, a DC voltage obtained by smoothing a PWM signal with a capacitor is input to the non-inverting input terminal as a dimming signal. For example, a DC voltage corresponding to the dimming degree is input to the non-inverting input terminal as a dimming signal.

  The voltage level of the dimming signal is set corresponding to the voltage level of the detection voltage of the load current input to the inverting input terminal. More specifically, for example, the voltage level of the dimming signal corresponding to the desired dimming level is substantially the same as the voltage level of the detection voltage when the light source module 100 is turned on with the luminance corresponding to the dimming level. Set to

  Thus, the detection voltage corresponding to the load current is input to the inverting input terminal, and the dimming signal is input to the non-inverting input terminal. As a result, a signal corresponding to the difference between the detected voltage and the dimming signal is output from the output terminal of the operational amplifier 80. The operational amplifier 80 is a differential amplifier circuit, for example. The output terminal of the operational amplifier 80 is electrically connected to the control unit 30. The output signal of the operational amplifier 80 is input to the second drive circuit 24. In contrast to the above, the detection voltage may be input to the non-inverting input terminal and the dimming signal may be input to the inverting input terminal.

  For example, as the detection voltage becomes larger than the dimming signal, the output of the operational amplifier 80 increases. In this case, the second drive circuit 24 controls the switching of the second switching element 45 so that the load current is reduced based on the signal input from the operational amplifier 80. The second drive circuit 24 changes the switching frequency of the second switching element 45 in accordance with the signal from the operational amplifier 80. Thereby, the illumination load 102 can be lighted with the brightness according to the light control signal. That is, the second drive circuit 24 can be feedback-controlled according to the load current flowing through the illumination load 102. Further, for example, an overcurrent flowing through the light source module 100 can be suppressed.

FIG. 2 is a table illustrating an example of the operation of the lighting device according to the first embodiment.
For example, when the power supply voltage of the AC power supply 4 is AC 242V (effective value) and the dimming degree is the dimming lower limit, the first drive voltage VCC1 and the second drive voltage VCC2 are the lowest. For this reason, as illustrated in FIG. 2, the control unit 30 sets both the first switch unit 27 and the second switch unit 28 to the supply state under the above-described conditions.

  On the other hand, when the power supply voltage of the AC power supply 4 is AC 100V (effective value) and the dimming degree is all light, the first drive voltage VCC1 and the second drive voltage VCC2 are the highest. For this reason, the control part 30 makes the 1st switch part 27 a non-supply state in the said conditions, and turns on / off the switching element 65 of the 2nd switch part 28. FIG. That is, the second switch unit 28 periodically repeats the supply state and the non-supply state.

  Here, the “dimming lower limit” is, in other words, a state where the dimming degree set by the dimming signal is less than the first threshold value. In other words, “light control middle” is a state in which the light control level is equal to or higher than the first threshold and lower than the second threshold greater than the first threshold. In other words, “all light” is a state in which the dimming degree is equal to or greater than the second threshold value. The “dimming lower limit” includes a state in which the illumination load 102 is turned off by inputting a light-off dimming signal, a so-called dimming OFF signal.

  As described above, the control unit 30 controls the switching of the first switch unit 27 and the second switch unit 28 in accordance with the detected value of the input voltage, and the first switch unit 27 and the second switch in accordance with the dimming signal. The switching of each of the two switch units 28 is controlled.

  The time for turning on the second switching element 45 in the all-light state is longer than the time for turning on the second switching element 45 in the dimming lower limit state. For this reason, the second drive voltage VCC2 in the all-light state is higher than the second drive voltage VCC in the dimming lower limit state. Therefore, when the dimming degree is equal to or higher than the predetermined value, the control unit 30 sets the first switch unit 27 in a non-supply state and only supplies the second drive voltage VCC2. In other words, when the second drive voltage VCC2 is equal to or higher than the predetermined value, the control unit 30 sets the first switch unit 27 in a non-supply state and only supplies the second drive voltage VCC2. Thereby, for example, circuit efficiency can be improved.

  As described above, the first drive circuit 23 generates the substantially constant first DC voltage regardless of the voltage value of the input voltage. The first DC voltage is higher than the input voltage. In other words, the first DC voltage is higher than the effective value of the power supply voltage of the AC power supply 4. In this case, the time for which the first switching element 41 is turned on when the power supply voltage is AC 100V is longer than the time for which the first switching element 41 is turned on when the power supply voltage is AC 242V. For this reason, in the above case, the first drive voltage VCC1 when the power supply voltage is AC 100V is higher than the first drive voltage VCC1 when the power supply voltage is AC 242V. Therefore, when the power supply voltage (input voltage) is equal to or lower than the predetermined value, the control unit 30 repeats the supply state and the non-supply state in the first switch unit 27. In other words, the control unit 30 repeats the supply state and the non-supply state in the first switch unit 27 when the first drive voltage VCC1 is greater than or equal to a predetermined value. For example, when the first drive voltage VCC1 is greater than or equal to a predetermined value, the second switch unit 28 may be in a non-supply state and only the first drive voltage VCC1 may be supplied. Thereby, for example, circuit efficiency can be improved.

  In this example, switching between the first switch unit 27 and the second switch unit 28 is controlled based on both the first drive voltage VCC1 and the second drive voltage VCC2. Without being limited thereto, the switching of the first switch unit 27 and the second switch unit 28 may be performed based on only one of the first drive voltage VCC1 and the second drive voltage VCC2. It should be noted that the cycle (duty ratio) when the supply state and non-supply state of each of the switch units 27 and 28 are repeated can be appropriately set according to the required voltage values of the first drive voltage VCC1 and the second drive voltage VCC2. Good. When the dimming OFF signal is input, the control unit 30 and the first drive circuit 23 control the first switching element 41 of the first chopper circuit 21 so as to increase the output voltage of the first chopper circuit 21. By doing so, the first drive voltage VCC1 may be reliably ensured.

  For example, there is a lighting device using an IPD (intelligent power device). However, IPD is relatively expensive and causes an increase in the cost of the lighting device. On the other hand, when the IPD is not used, for example, it is necessary to set the drive voltage according to the dimming lower limit. In this case, a driving voltage more than necessary is generated at the time of all light, and the circuit loss increases.

  On the other hand, in the lighting device 10 according to the present embodiment, the first drive circuit 23, the second drive circuit 24, the control unit 30, and the like are configured using a general-purpose microcomputer or the like without using the IPD. Thereby, the cost increase of the lighting device 10 can be suppressed, for example. Further, the lighting device 10 controls switching of the first switch unit 27 and the second switch unit 28 based on at least one of the first drive voltage VCC1 and the second drive voltage VCC2. Thereby, circuit efficiency can be improved. Thus, in the lighting device 10 and the lighting device 200 according to the present embodiment, a simple circuit and good circuit efficiency can be obtained.

(Second Embodiment)
FIG. 3 is a block diagram schematically illustrating the illumination device according to the second embodiment.
As shown in FIG. 3, in the lighting device 310 of the lighting device 300, the second switch unit 28 is omitted, and the second secondary winding 26 supplies the second drive voltage VCC <b> 2 to the control unit 30.

  The control unit 30 of the lighting device 310 sets the first switch unit 27 in a non-supply state when the second drive voltage VCC2 is greater than or equal to a predetermined value, and supplies the first switch unit 27 when the second drive voltage VCC2 is less than the predetermined value. To. For example, when the dimming degree represented by the dimming signal is less than a predetermined value, the control unit 30 determines that the second drive voltage VCC2 is less than the predetermined value.

  The lighting device 310 of the lighting device 300 supplies the first drive voltage VCC1 only when the second drive voltage VCC2 is insufficient during dimming. Thereby, for example, the power loss due to the first drive voltage VCC1 can be suppressed during all light. Thus, the lighting device 310 and the lighting device 300 according to the present embodiment can obtain a simple circuit and good circuit efficiency.

  In this example, the first drive voltage VCC1 and the second drive voltage VCC2 are supplied to the first drive circuit 23, the second drive circuit 24, and the control unit 30. The first drive voltage VCC1 and the second drive voltage VCC2 may be supplied only to the control unit 30.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 4 ... AC power supply 10, 310 ... Lighting device, 12 ... Main-body part, 14 ... Connection part, 21 ... 1st chopper circuit, 22 ... 2nd chopper circuit, 23 ... 1st drive circuit, 24 ... 2nd drive circuit, 25 ... 1st secondary winding, 26 ... 2nd secondary winding, 27 ... 1st switch part, 28 ... 2nd switch part, 30 ... Control part, 31 ... Filter circuit, 32 ... Rectifier circuit, 33, 34 , Smoothing capacitor, 35 output capacitor, 41 first switching element, 42 first inductor, 43 first diode, 45 second switching element, 46 second diode, 47 second inductor, 50 resistance , 51 ... capacitor, 52 ... resistor, 53 ... capacitor, 60, 61, 64, 65 ... switching element, 62, 66 ... resistor, 70 to 73 ... resistor, 75 ... rectifier, 76 ... photocoupler, 80 ... ampere Flop, 82 ... current detection resistor, 83, 84 ... resistors, 100 ... light source module, 102 ... lighting load, 104 ... connected part, 106 ... light source, 200, 300 ... lighting device

Claims (7)

A first chopper circuit having a first switching element and a first inductor, and converting an input voltage into a first DC voltage by switching of the first switching element;
The first chopper circuit and the illumination load are electrically connected to each other, have a second switching element and a second inductor, and convert the first DC voltage to a second DC voltage by switching the second switching element. A second chopper circuit for outputting the second DC voltage to the lighting load;
A first drive circuit for controlling the switching of the first switching element;
A second drive circuit for controlling the switching of the second switching element;
A first secondary winding that is magnetically coupled to the first inductor and generates a first drive voltage in accordance with a current flowing through the first inductor;
A second secondary winding that is magnetically coupled to the second inductor and generates a second drive voltage according to a current flowing through the second inductor;
A first switch unit that switches between a supply state and a non-supply state of the first drive voltage;
A control unit that controls switching of the first switch unit according to at least one of the first drive voltage and the second drive voltage;
Lighting device with A second switch unit that switches between a supply state and a non-supply state of the second drive voltage;
The first switch unit switches between a supply state and a non-supply state of the first drive voltage to the first drive circuit and the second drive circuit,
The second switch unit switches between a supply state and a non-supply state of the second drive voltage to the first drive circuit and the second drive circuit,
The lighting device according to claim 1, wherein the control unit controls switching of the first switch unit and the second switch unit.   The lighting device according to claim 2, wherein the control unit detects the input voltage and controls the switching of the first switch unit and the second switch unit according to a detection value of the input voltage. The second drive circuit controls the switching of the second switching element according to a dimming signal input from the outside,
The lighting device according to claim 2 or 3, wherein the control unit controls the switching of the first switch unit and the second switch unit according to the dimming signal. The first switch unit switches between a supply state and a non-supply state of the first drive voltage to the control unit,
The second secondary winding supplies a second drive voltage to the control unit,
The control unit sets the first switch unit to the non-supply state when the second drive voltage is equal to or higher than a predetermined value, and sets the first switch unit to the supply state when the second drive voltage is lower than the predetermined value. The lighting device according to claim 1. The second drive circuit controls the switching of the second switching element according to a dimming signal input from the outside,
The lighting device according to claim 5, wherein the control unit determines that the second drive voltage is less than the predetermined value when a dimming degree represented by the dimming signal is less than a predetermined value. Lighting load,
The lighting device according to any one of claims 1 to 6,
A lighting device comprising:

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