JP6256755B2 - Lighting device and lighting device - Google Patents

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 the lighting device, so-called dimming is performed in which the brightness of light emitted from the illumination load is adjusted based on a signal input from the outside. In such a lighting device, when the power supply to the lighting load is started, there may be a flash phenomenon in which the lighting load is temporarily turned on with a brightness higher than the set brightness. Such a flash phenomenon is uncomfortable for the user. For this reason, in a lighting device, it is desired to suppress the occurrence of an unintended flash phenomenon at the start of power supply.

Japanese Patent No. 4636102

  Embodiments of the present invention provide a lighting device and a lighting device that suppress the occurrence of an unintended flash phenomenon when power supply to a lighting load is started.

According to the embodiment of the present invention, a lighting device including a power supply unit, a signal generation unit, a drive circuit, and a signal control unit is provided. The power supply unit includes a switching element, is electrically connected to a lighting load, and converts the input power into DC power corresponding to the lighting load by switching the switching element, and converts the DC power to the lighting Supply to load. The signal generation unit includes a first input terminal to which a dimming signal is input, and an output terminal, and generates a control signal for lighting the lighting load with brightness according to the dimming signal, The control signal is output from the output terminal. The drive circuit is electrically connected to the output terminal and controls switching of the switching element according to the control signal input from the signal generation unit. The signal control unit sets the control signal to be less than the maximum value of the control signal until a predetermined time elapses from the timing when the drive circuit starts switching of the switching element. The power supply unit is a chopper circuit further including an inductor and a diode. The signal generation unit further includes a second input terminal to which a detection voltage of a load current flowing through the lighting load is input, and generates the control signal based on the dimming signal and the detection voltage. The signal control unit includes a secondary winding magnetically coupled to the inductor, and a differentiating circuit electrically connected between the secondary winding and the second input terminal.

  Provided are a lighting device and a lighting device that suppress the occurrence of an unintended flash phenomenon when power supply to a lighting load is started.

It is a block diagram showing typically the lighting installation concerning a 1st embodiment. It is a block diagram which represents typically the illuminating device which concerns on 2nd Embodiment. It is a block diagram which represents typically the illuminating device which concerns on 3rd 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.
In the present specification and drawings, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof will be 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.

  For example, the lighting device 10 is electrically connected to the AC power supply 4. 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 26 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 specification of the present application, “electrically connected” includes not only the case of being connected by direct contact but also the case of being connected via another conductive member.

  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 control unit 12, a connection unit 14, and a power supply unit 16. The control unit 12 comprehensively controls each unit of the lighting device 10. 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 power supply unit 16 is electrically connected to the connection unit 14. The power supply unit 16 converts the input power into DC power corresponding to the light source module 100. Then, the power supply unit 16 supplies the converted DC power to the light source module 100 connected to the connection unit 14.

  The lighting device 10 further includes, for example, a filter circuit 24, a rectifier circuit 26, an inrush prevention circuit 28, a power supply voltage detection circuit 30, a power factor correction circuit 32, a smoothing capacitor 34, a control power supply circuit 36, and an output capacitor 38. .

  The filter circuit 24 is electrically connected to the AC power supply 4. For example, the filter circuit 24 suppresses noise included in AC power supplied from the AC power supply 4.

  The rectifier circuit 26 is electrically connected to the filter circuit 24. The rectifier circuit 26 rectifies the AC voltage input via the filter circuit 24 and converts it into a rectified voltage. For the rectifier circuit 26, for example, a diode bridge in which four rectifier elements are combined is used. That is, the rectifier circuit 26 is a full-wave rectifier. The rectified voltage is, for example, a pulsating voltage.

  The rectifier circuit 26 has a pair of input terminals 26a and 26b, a high potential output terminal 26c, and a low potential output terminal 26d. The input terminals 26 a and 26 b are electrically connected to the filter circuit 24. The rectifier circuit 26 converts an alternating voltage input via the input terminals 26a and 26b into a rectified voltage, and outputs the rectified voltage from the high potential output terminal 26c and the low potential output terminal 26d. The potential of the low potential output terminal 26d is set to a reference potential (for example, ground potential). The potential of the high potential output terminal 26c is set to a potential higher than that of the low potential output terminal 26d.

  The rectifier circuit 26 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 26, for example, a Schottky barrier diode is used. Thereby, for example, good responsiveness can be obtained.

  The inrush prevention circuit 28 is electrically connected to the high potential output terminal 26c. The inrush prevention circuit 28 suppresses an inrush current generated when the power is turned on.

  The power supply voltage detection circuit 30 is connected to the output of the inrush prevention circuit 28. The power supply voltage detection circuit 30 is connected, for example, between the output of the inrush prevention circuit 28 and the low potential output terminal 26d. The power supply voltage detection circuit 30 detects an abnormality in the AC voltage supplied from the AC power supply 4. The power supply voltage detection circuit 30 detects an abnormality in the AC voltage based on, for example, the rectified voltage rectified by the rectifier circuit 26. For example, the power supply voltage detection circuit 30 determines whether or not the effective value of the rectified voltage is within a predetermined range, and determines that the AC voltage is abnormal when it is not within the predetermined range. That is, the power supply voltage detection circuit 30 makes the AC voltage abnormal when the effective value of the AC voltage is excessively small or excessively large.

  The power supply voltage detection circuit 30 is electrically connected to the control unit 12. The power supply voltage detection circuit 30 outputs information indicating the detection result of the AC voltage abnormality to the control unit 12. The control unit 12 causes the power supply unit 16 to stop supplying DC power to the light source module 100 when an abnormality in AC voltage is detected by the power supply voltage detection circuit 30. Thereby, for example, failure of the light source module 100 due to application of an abnormal voltage can be suppressed.

  The power factor correction circuit 32 is connected between the output of the inrush prevention circuit 28 and the low potential output terminal 26d. The power factor correction circuit 32 suppresses generation of harmonics that are an integral multiple of the power supply frequency in the rectified voltage. Thereby, the power factor improvement circuit 32 improves the power factor of the rectified voltage.

  The power factor correction circuit 32 includes, for example, a switching element 41, an inductor 42, and a diode 43. The switching element 41 includes electrodes 41a to 41c. One end of the inductor 42 is electrically connected to the output (high potential output terminal 26c) of the inrush prevention circuit 28. The other end of the inductor 42 is electrically connected to the electrode 41a. The electrode 41b is electrically connected to the low potential output terminal 26d. The anode of the diode 43 is electrically connected to the electrode 41a. The cathode of the 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 26d. That is, in this example, the power factor correction circuit 32 is a boost chopper circuit. The power factor correction circuit 32 is not limited to this, and may be any circuit that can improve the power factor of the rectified voltage.

  The electrode 41c is electrically connected to the control unit 12. The electrode 41c is a so-called control electrode. The switching element 41 performs switching according to a signal from the control unit 12. The power factor correction circuit 32 improves the power factor, for example, by switching the switching element 41 and bringing the input current closer to a sine wave.

  The 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. For example, the switching element 41 may be a p-channel FET or a bipolar transistor.

  The smoothing capacitor 34 converts the pulsating voltage into a DC voltage by smoothing the pulsating voltage after power factor improvement.

  The control power supply circuit 36 is electrically connected to, for example, one end of the smoothing capacitor 34 on the high potential side. As a result, the DC voltage smoothed by the smoothing capacitor 34 is input to the control power supply circuit 36. The control power supply circuit 36 converts the DC voltage smoothed by the smoothing capacitor 34 into a drive voltage for the control unit 12 and supplies it to the control unit 12. The control unit 12 is driven in response to power supply from the control power supply circuit 36.

  The power supply unit 16 includes a first input terminal 16a, a second input terminal 16b, a first output terminal 16c, and a second output terminal 16d. The first input terminal 16 a is electrically connected to one end on the high potential side of the smoothing capacitor 34. The second input terminal 16b is electrically connected to the low potential output terminal 26d. As a result, a DC voltage is supplied to the power supply unit 16. The first output terminal 16 c is electrically connected to one end of the output capacitor 38. The second output terminal 16d is electrically connected to the other end of the output capacitor 38. For example, the power supply unit 16 supplies one of the first DC power and the second DC power to the light source module 100 from the first output terminal 16c and the second output terminal 16d.

  The power supply unit 16 includes, for example, a switching element 45, a diode 46, and an inductor 47. Switching element 45 includes an electrode 45a, an electrode 45b, and an electrode 45c. The electrode 45a is electrically connected to the first input terminal 16a. The electrode 45 b is electrically connected to the cathode of the diode 46. The anode of the diode 46 is electrically connected to the low potential output terminal 26d. One end of the inductor 47 is electrically connected to the electrode 45b. The other end of the inductor 47 is electrically connected to the first output terminal 16c. The second output terminal 16d is electrically connected to the low potential output terminal 26d. That is, the first output terminal 16c is an output terminal on the high potential side, and the second output terminal 16d is an output terminal on the low potential side. The potential of the first output terminal 16c is higher than the potential of the second output terminal 16d. On the contrary, the potential of the second output terminal 16d may be higher than the potential of the first output terminal 16c. In this example, the power supply unit 16 is a chopper circuit. The power supply unit 16 is, for example, a step-down chopper circuit. The power supply unit 16 is, for example, a constant current circuit.

  The electrode 45c is electrically connected to the control unit 12. The electrode 45c is a so-called control electrode. The switching element 45 performs switching according to a signal from the control unit 12. For example, the control unit 12 switches the switching element 45 to generate a DC voltage across the output capacitor 38. As a result, power is supplied from the power supply unit 16 to the light source module 100. And the control part 12 stops supply of the electric power from the power supply part 16 to the light source module 100 by making the switching element 45 into an OFF state, for example.

  The 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 switching element 45 may be a p-channel FET or a bipolar transistor.

  The power supply unit 16 is not limited to the above circuit, and may be any circuit that can supply DC power to the light source module 100.

  The lighting device 10 further includes a light control circuit 50, a signal generation unit 52, and a changeover switch 54.

  A dimming signal is input to the dimming circuit 50 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 may be, for example, an AC voltage whose conduction angle is controlled by a dimmer or the like. The dimming circuit 50 is electrically connected to the control unit 12. The dimming circuit 50 inputs a dimming signal to the control unit 12. For example, the dimming circuit 50 converts a dimming signal input from the outside into a format corresponding to the control unit 12, and inputs the converted dimming signal to the control unit 12. The dimming signal input to the control unit 12 is, for example, a PWM signal having a duty ratio corresponding to the dimming degree.

  The signal generation unit 52 generates a control signal for lighting the illumination load 102 of the light source module 100 with brightness according to the dimming signal input from the outside. The signal generator 52 is electrically connected to the controller 12. The signal generation unit 52 outputs the generated control signal to the control unit 12.

  The signal generation unit 52 includes an operational amplifier 60, a current detection resistor 62, and resistors 63 to 66. The current detection resistor 62 is electrically connected between the second output terminal 16 d and the low potential side terminal of the connection portion 14. In other words, the current detection resistor 62 is electrically connected between the second output terminal 16 d and the low potential side terminal of the output capacitor 38. Thereby, the current detection resistor 62 is used to detect a load current flowing through the illumination load 102.

  The operational amplifier 60 includes a non-inverting input terminal 60a (first input terminal), an inverting input terminal 60b (second input terminal), and an output terminal 60c.

  The inverting input terminal 60 b is connected to one end of the resistor 63 and one end of the resistor 64. The other end of the resistor 63 is electrically connected to the current detection resistor 62. The other end of the resistor 64 is electrically connected to the low potential output terminal 26 d of the rectifier circuit 26. As a result, a voltage corresponding to the load current is input to the inverting input terminal 60b.

  The non-inverting input terminal 60a is electrically connected to the control unit 12. A dimming signal is input from the control unit 12 to the non-inverting input terminal 60a. For example, a DC voltage obtained by smoothing a PWM signal with a capacitor is input to the non-inverting input terminal 60a as a dimming signal. For example, a DC voltage corresponding to the dimming degree is input to the non-inverting input terminal 60a 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 60b. 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 60b, and the dimming signal is input to the non-inverting input terminal 60a. Thereby, a signal corresponding to the difference between the detected voltage and the dimming signal is output from the output terminal 60 c of the operational amplifier 60. The operational amplifier 60 is, for example, a differential amplifier circuit. An output terminal 60 c of the operational amplifier 60 is electrically connected to the control unit 12. An output signal of the operational amplifier 60 is input to the control unit 12. In contrast to the above, the detection voltage may be input to the non-inverting input terminal 60a and the dimming signal may be input to the inverting input terminal 60b.

  For example, as the detection voltage becomes larger than the dimming signal, the output of the operational amplifier 60 increases. In this case, the control unit 12 controls the switching of the switching element 45 so that the load current is reduced based on the signal input from the operational amplifier 60. Thereby, the illumination load 102 can be lighted with the brightness according to the light control signal. Further, for example, an overcurrent flowing through the light source module 100 can be suppressed.

  Thus, in this example, the signal generation unit 52 generates a control signal based on the detected voltage and the dimming signal. For example, the signal generation unit 52 generates a difference signal between the detection voltage and the dimming signal as a control signal. The control signal is not limited to a difference signal between the detection voltage and the dimming signal, and may be any signal that can light the illumination load 102 with brightness according to the dimming signal. The signal generator 52 is not limited to the above, and may be any circuit that can generate a control signal.

  The changeover switch 54 is electrically connected to the output of the signal generator 52. In this example, the changeover switch 54 is electrically connected to the output terminal 60 c of the operational amplifier 60. The changeover switch 54 includes, for example, a pair of main electrodes 54a and 54b and a control electrode 54c. The changeover switch 54 switches the amount of current flowing between the main electrodes 54a and 54b by turning on and off. The control electrode 54c is used for on / off switching. The on state is a state in which current flows between the main electrodes 54a and 54b. The off state is a state in which the current flowing between the main electrodes 54a and 54b is smaller than the on state. In the off state, substantially no current flows between the main electrodes 54a and 54b. In the off state, a weak current that does not affect the operation of the lighting device 10 may flow between the main electrodes 54a and 54b.

  For example, a semiconductor switch is used as the changeover switch 54. In this example, the changeover switch 54 is an npn-type bipolar transistor. The changeover switch 54 may be a mechanical relay or the like.

  The main electrode 54a is electrically connected to the output terminal 60c of the operational amplifier 60. The main electrode 54b is electrically connected to the low potential output terminal 26d of the rectifier circuit 26. Thereby, when the changeover switch 54 is turned on, the control signal output from the signal generator 52 is set to a predetermined potential that is less than the maximum value of the control signal. In other words, the potential of the output terminal 60c is set to a predetermined potential. The potential of the control signal is set to the potential of the low potential output terminal 26d, for example.

  The control unit 12 includes a control circuit 70 and drive circuits 71 and 72. The control unit 12 may be configured by one integrated circuit made into one chip, or may be configured by combining a plurality of integrated circuits. The control circuit 70 and the drive circuits 71 and 72 may be logic blocks provided in one integrated circuit, or may be independent control ICs.

  The drive circuit 71 is electrically connected to the signal generator 52 and the electrode 45 c of the switching element 45. The control signal output from the signal generator 52 is input to the drive circuit 71. The drive circuit 71 controls switching of the switching element 45 in accordance with the input control signal. That is, the drive circuit 71 controls the conversion to DC power in the power supply unit 16.

  The drive circuit 72 is electrically connected to the electrode 41 c of the switching element 41. The drive circuit 72 controls switching of the switching element 41. That is, the drive circuit 72 controls the power factor improvement process in the power factor improvement circuit 32.

  The control circuit 70 is electrically connected to the dimming circuit 50 and the signal generation unit 52. The control circuit 70 inputs the dimming signal input from the dimming circuit 50 to the signal generation unit 52. More specifically, the control circuit 70 is electrically connected to the non-inverting input terminal 60a. The control circuit 70 inputs the dimming signal to the non-inverting input terminal 60a.

  The control circuit 70 is electrically connected to the control electrode 54c of the changeover switch 54. The control circuit 70 controls on / off switching of the changeover switch 54. The control circuit 70 turns on the changeover switch 54 until a predetermined time elapses from the timing at which the drive circuit 71 starts switching of the switching element 45 (hereinafter referred to as start timing). Then, the control circuit 70 turns off the changeover switch 54 after a predetermined time has elapsed from the start timing.

  Thus, the control signal is set to be less than the maximum value until a predetermined time has elapsed from the start timing. That is, in this example, the signal control unit 56 that sets the control signal to be less than the maximum value until a predetermined time elapses from the start timing includes the changeover switch 54 and the control circuit 70.

  For example, the signal control unit 56 sets the control signal below the median value of the control signal at the start timing. That is, the signal control unit 56 sets the control signal to a value equal to or less than the value when the dimming degree is set to 50%, for example. For example, the signal control unit 56 may set the control signal to 10% or less of the maximum value of the control signal at the start timing. The value of the control signal set by the signal controller 56 may be larger than the minimum value of the control signal and smaller than the maximum value of the control signal. The minimum value of the control signal is a value when the dimming degree is set to 0%. The value of the control signal set by the signal control unit 56 is preferably as small as possible. For example, it is preferably 1% or more and 10% or less of the maximum value.

  The start timing is, for example, when the lighting device 10 is turned on and when dimming is released. For example, the control circuit 70 turns on the changeover switch 54 until a predetermined time elapses from when it is activated in response to power supply from the AC power supply 4 or the like. For example, the control circuit 70 turns on the changeover switch 54 until a predetermined time elapses after the dimming is turned off. That is, in other words, the start timing is a timing at which power supply to the lighting load 102 is started. Here, “when dimming off is released” means that the lighting load 102 is turned on by setting the dimming degree to be greater than 0% from the state in which the dimming degree is set to 0% and the lighting load 102 is turned off. It's time.

  For example, the control circuit 70 is activated in response to power supply, and then turns on the changeover switch 54. For example, the control circuit 70 may be activated in response to power supply, detect power-on based on the detection result of the power supply voltage detection circuit 30, and turn on the changeover switch 54 after detecting power-on. In this case, for example, after the control circuit 70 detects power-on, the operation of the drive circuit 71 is started.

  The changeover switch 54 may be a normally-on type element, and the changeover switch 54 may be turned off after a predetermined time has elapsed. Thereby, for example, even when the control circuit 70 is not activated when the power is turned on, the control signal can be appropriately set to be less than the maximum value.

  In the lighting device, when the lighting load is turned on by starting the power supply to the lighting load, the lighting load may be turned on with a higher brightness than the brightness set by the dimming signal. Such a flash phenomenon is uncomfortable for the user.

  The inventor of the present application has found that the cause of the flash phenomenon is the control signal output from the signal generation unit. Depending on the specifications of an operational amplifier (error amplifier) used for the signal generation unit, the control signal may become a maximum value at the start of power supply (switching start timing). In this case, the value of the control signal becomes a value corresponding to the dimming signal from the maximum value with time. That is, the control signal may fluctuate at the start of power supply, such as increasing from the minimum value to the maximum value and then decreasing from the maximum value to a value corresponding to the dimming signal. The inventor of the present application has found that the flash phenomenon occurs due to the fluctuation of the control signal at the start of the power supply.

  On the other hand, in the lighting device 10 according to the present embodiment, the signal control unit 56 sets the control signal to be less than the maximum value until a predetermined time elapses from the start timing. In the lighting device 10, the control signal can be set to a value less than the maximum value in a section where the control signal varies. In the lighting device 10, a control signal having a value corresponding to the dimming signal can be input to the drive circuit 71. Thereby, in the lighting device 10 and the lighting device 200 according to the present embodiment, it is possible to suppress the occurrence of an unintended flash phenomenon when the power supply to the lighting load 102 is started.

  For example, there is a lighting device that uses a high-performance control element such as a microcomputer to soft-start the power supply unit 16 at the start of power supply, thereby suppressing the current flowing through the lighting load 102 at the start of power supply. However, a control element capable of a soft start operation is relatively expensive. For this reason, for example, the manufacturing cost of the lighting device is increased.

  On the other hand, in the lighting device 10 according to the present embodiment, the occurrence of the flash phenomenon can be suppressed even if an inexpensive element that does not perform the soft start operation is used. Therefore, in the lighting device 10, for example, the manufacturing cost can be suppressed.

  The predetermined time for setting the control signal below the maximum value is, for example, not less than 0.1 seconds and not more than 0.5 seconds. The predetermined time for setting the control signal below the maximum value may be set in accordance with the time until the output of the control signal is stabilized. In other words, the predetermined time may be longer than the time of the section in which the control signal varies.

(Second Embodiment)
FIG. 2 is a block diagram schematically illustrating the illumination device according to the second embodiment.
As shown in FIG. 2, in the lighting device 80 of the lighting device 210, the signal control unit 56 includes a secondary winding 81 and a differentiation circuit 82.

  The secondary winding 81 is magnetically coupled to the inductor 47 of the power supply unit 16. For example, the secondary winding 81 forms a transformer together with the inductor 47. One end of the secondary winding 81 is electrically connected to the low potential output terminal 26 d of the rectifier circuit 26.

  The differentiation circuit 82 is electrically connected between the secondary winding 81 and the inverting input terminal 60 b of the operational amplifier 60. Differentiating circuit 82 includes a capacitor 83 and a resistor 84. One end of the capacitor 83 is electrically connected to the other end of the secondary winding 81. The other end of the capacitor 83 is electrically connected to one end of the resistor 84. The other end of the resistor 84 is electrically connected to the inverting input terminal 60b.

  Thereby, the signal control unit 56 starts switching of the switching element 45 and applies a voltage higher than that of the non-inverting input terminal 60a to the inverting input terminal 60b of the operational amplifier 60 in a transient period in which the current flowing through the inductor 47 increases. Apply. That is, at the start timing, the detection voltage is set higher than the dimming signal.

  Thereby, also in the lighting device 80, the control signal can be set to less than the maximum value until a predetermined time elapses from the start timing. More specifically, the control signal can be set to less than the maximum value from the start timing until the current flowing through the inductor 47 becomes substantially constant.

  Therefore, also in the lighting device 80 and the lighting device 210, it is possible to suppress the occurrence of an unintended flash phenomenon when starting the power supply to the lighting load 102, as in the first embodiment. For example, the manufacturing cost of the lighting device 80 can be suppressed.

(Third embodiment)
FIG. 3 is a block diagram schematically illustrating a lighting device according to the third embodiment.
As shown in FIG. 3, in the lighting device 90 of the lighting device 220, the signal control unit 56 includes a changeover switch 54, a secondary winding 81, and a differentiation circuit 82.

  In the signal control unit 56 of the lighting device 90, the other end of the resistor 84 is electrically connected to the control electrode 54 c of the changeover switch 54. Accordingly, the signal control unit 56 turns on the changeover switch 54 in a transitional period in which the switching of the switching element 45 is started and the current flowing through the inductor 47 increases.

  Thereby, also in the lighting device 90, the control signal can be set to be less than the maximum value until a predetermined time elapses from the start timing. Therefore, also in the lighting device 90 and the lighting device 220, as in the first embodiment and the second embodiment, the occurrence of an unintended flash phenomenon when the power supply to the lighting load 102 is started is suppressed. can do. For example, the manufacturing cost of the lighting device 80 can be suppressed.

  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, 80, 90 ... Lighting device, 12 ... Control part, 14 ... Connection part, 16 ... Power supply part, 24 ... Filter circuit, 26 ... Rectification circuit, 28 ... Inrush prevention circuit, 30 ... Power supply voltage Detection circuit 32 ... Power factor correction circuit 34 ... Smoothing capacitor 36 ... Power supply for control 38 ... Output capacitor 41 ... Switching element 42 ... Inductor 43 ... Diode 45 ... Switching element 46 ... Diode 47 DESCRIPTION OF SYMBOLS ... Inductor, 50 ... Dimming circuit, 52 ... Signal generation part, 54 ... Changeover switch, 60 ... Operational amplifier, 62 ... Current detection resistance, 63-66 ... Resistance, 70 ... Control circuit, 71, 72 ... Drive circuit, 81 ... Secondary winding, 82 ... differentiation circuit, 83 ... capacitor, 84 ... resistance, 100 ... light source module, 102 ... lighting load, 104 ... connected part, 106 ... light source, 200 210, 220 ... lighting device

Claims (3)

A power supply that includes a switching element, is electrically connected to the lighting load, converts the input power into DC power corresponding to the lighting load, and supplies the DC power to the lighting load by switching of the switching element And
A first input terminal to which a dimming signal is input; and an output terminal; generating a control signal for lighting the lighting load with brightness according to the dimming signal; and outputting the control signal A signal generator that outputs from the terminal;
A drive circuit that is electrically connected to the output terminal and controls switching of the switching element according to the control signal input from the signal generation unit;
A signal control unit that sets the control signal to be less than the maximum value of the control signal until a predetermined time elapses from the timing at which the drive circuit starts switching of the switching element;
Equipped with a,
The power supply unit is a chopper circuit further including an inductor and a diode,
The signal generation unit further includes a second input terminal to which a detection voltage of a load current flowing through the lighting load is input, and generates the control signal based on the dimming signal and the detection voltage,
The signal controller is
A secondary winding magnetically coupled to the inductor;
A differential circuit electrically connected between the secondary winding and the second input terminal;
Including lighting device. A power supply that includes a switching element, is electrically connected to the lighting load, converts the input power into DC power corresponding to the lighting load, and supplies the DC power to the lighting load by switching of the switching element And
A first input terminal to which a dimming signal is input; and an output terminal; generating a control signal for lighting the lighting load with brightness according to the dimming signal; and outputting the control signal A signal generator that outputs from the terminal;
A drive circuit that is electrically connected to the output terminal and controls switching of the switching element according to the control signal input from the signal generation unit;
A signal control unit that sets the control signal to be less than the maximum value of the control signal until a predetermined time elapses from the timing at which the drive circuit starts switching of the switching element;
With
The power supply unit is a chopper circuit further including an inductor and a diode,
The signal controller is
A changeover switch having a control electrode used for on / off switching, electrically connected to the output terminal, and configured to set the potential of the control signal to a predetermined potential which is less than the maximum value when in the on state; ,
A secondary winding magnetically coupled to the inductor;
A differential circuit electrically connected between the secondary winding and the control electrode;
Including lighting device. Lighting load,
The lighting device according to claim 1 or 2 ,
A lighting device comprising:

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