JP6374783B2 - Lighting device - Google Patents

Description

  The present invention relates to a lighting device including a plurality of light emitting elements.

  In recent years, with diversification of lighting device designs, for example, as disclosed in Patent Document 1 and Patent Document 2, a plurality of light emitting element groups connected to a power supply circuit in parallel to each other have different numbers of light emitting elements. A lighting device having the following is known.

JP 2010-225413 A JP 2008-77944 A

  In the conventional lighting device as described above, the light emission reference voltage required for light emission may differ between the light emitting element groups. For example, when the power source for driving the lighting device is turned on or off, the power is supplied. When the voltage supplied from the circuit is not at a sufficient level, the timing of light emission and extinction of the light emitting elements of each light emitting element group may vary. If the timing of light emission and extinction of each light emitting element group in the lighting device varies, the aesthetic appearance is impaired, and if the lighting device is used as an in-vehicle exterior lamp, for example, it may become unclear and may lead to an accident. Because there was a problem.

  The present invention provides an illumination device that prevents variations in the timing of light emission or extinction of a plurality of light emitting element groups connected in parallel to a power supply circuit.

  The lighting device according to the present invention has a power supply circuit for supplying a drive voltage, and a first light emission current flows when a first light emission voltage based on the drive voltage is applied at a first light emission reference voltage or higher. A first light emitting element group including a plurality of first light emitting elements arranged in series with each other, and a second light emission having a second light emission voltage based on the drive voltage higher than the first light emission reference voltage A second light-emitting element group including a plurality of second light-emitting elements connected in series, each of which emits light when a second light-emitting current flows when applied at a reference voltage. A light emitting element group that emits light when a light emission voltage equal to or higher than a light emission reference voltage based on the light emission reference voltage is detected, and a magnitude relationship between the drive voltage and the light emission reference voltage is detected, and the drive voltage is greater than the light emission reference voltage. Is larger, the light emitting element group emits light. That emission control was carried out, when the driving voltage is smaller than the emission reference voltage has a light emission control unit which performs light emission stop control to stop the light emission of the light emitting element group.

  According to the illumination device of the present invention, it is possible to prevent variations in the timing of light emission or extinction of a plurality of light emitting element groups connected in parallel to each other with respect to the power supply circuit.

It is the figure which showed the illuminating device 10 concerning the 1st Embodiment of this invention. It is the figure which showed the transition of each signal waveform between the rising of the power supply for driving the illuminating device 10, and falling. It is the figure which showed the illuminating device 10a concerning the 1st modification of the 1st Embodiment of this invention. It is the figure which showed the illuminating device 10b concerning the 2nd modification of the 1st Embodiment of this invention. It is the figure which showed the illuminating device 20 concerning the 2nd Embodiment of this invention. It is the figure which showed transition of each signal waveform between the rising of the power supply for driving the illuminating device 20, and falling. It is the figure which showed the illuminating device 20a concerning the 1st modification of the 2nd Embodiment of this invention. It is the figure which showed the illuminating device 30 concerning the 3rd Embodiment of this invention. It is the figure which showed the transition of each signal waveform between the rising of the power supply for driving the illuminating device 30, and falling. It is the figure which showed the illuminating device 30a concerning the 1st modification of the 3rd Embodiment of this invention. It is the figure which showed the illuminating device 30b concerning the 2nd modification of the 3rd Embodiment of this invention. It is the figure which showed the illuminating device 30c concerning the 3rd modification of the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The numerical values, circuits, etc. described below can be selected as appropriate without departing from the spirit of the present invention.

[First Embodiment]
FIG. 1 is a diagram showing an illumination device 10 according to the first embodiment of the present invention. The lighting device 10 includes a power supply circuit VS, a light emitting element group HS, and a light emission control unit HC. Although the illuminating device 10 is used as vehicle-mounted exterior lamps, such as a headlamp, a blinker, a hazard lamp, a brake lamp, for example, it is not restricted to this.

  The power supply circuit VS outputs a drive voltage Vk of 12V, for example. Further, the power supply circuit VS can supply a drive current Ik having a current value of a magnitude corresponding to the load to which the drive voltage Vk is supplied.

  The light emitting element group HS includes a light emitting element group HS1 as a first light emitting element group and a light emitting element group HS2 as a second light emitting element group. The light emitting element group HS is a load to which the drive voltage Vk is supplied.

  The light emitting element group HS1 includes a plurality of light emitting elements HS1a as first light emitting elements connected in series with each other, and a resistance element Rh1. The light emitting element HS1a is an LED (Light Emitting Diode) and is a self-light emitting element. The cathode of the light emitting element HS1a as one end of the light emitting element group HS1 is connected to one end of the resistance element Rh1. The other end of the resistance element Rh1 is connected to a power supply VSS as a first power supply having a potential lower than the drive voltage Vk, for example, 0V. Note that the light emitting element HS1a is not limited to an LED, and organic EL (Electro Luminescence) elements as self-luminous elements such as light emitting polymers are also applicable.

  The light emitting element group HS1 is applied to the anode of the light emitting element HS1a as its other end when the light emission voltage Vh1 as the first light emission voltage based on the drive voltage Vk is equal to or higher than the light emission reference voltage VH1 as the first light emission reference voltage. Then, when the light emission current Ih1 as the first light emission current flows to each of the light emitting elements HS1a, light is emitted. Note that the current value of the light emission current Ih1 is determined based on the resistance value of the resistance element Rh1. Each light emitting element HS1a has an internal resistance, and the forward voltage per light emitting element HS1a is 2 V, for example.

  Here, in the present embodiment, the light emission reference voltage VH1 for the light emitting element group HS1 to emit light includes three light emitting elements HS1a having a forward voltage of 2V in which the light emitting element groups HS1 are connected in series. For example, 6V. That is, in order for the light emitting element group HS1 to emit light, the light emission voltage Vh1 applied to the anode of the light emitting element HS1a at the other end needs to be 6V or more.

  Here, “the anode of the light emitting element HS1a as the other end of the light emitting element group HS1” is referred to as a node Nh1, and “the cathode of the light emitting element HS1a as one end of the light emitting element group HS1” is referred to as a node Nh1a. Further, “the light emission current Ih1 flows through each of the light emitting elements HS1a” is described as “the light emission current Ih1 flows through the light emitting element group HS1”.

  The light emitting element group HS2 includes a plurality of light emitting elements HS2a as second light emitting elements connected in series with each other, and a resistance element Rh2. The light emitting element HS2a is an LED (Light Emitting Diode) and is a self light emitting element. The cathode of the light emitting element HS2a as one end of the light emitting element group HS2 is connected to one end of the resistance element Rh2. The other end of the resistance element Rh2 is connected to the power supply VSS. Note that the light emitting element HS2a is not limited to an LED, and an organic EL (Electro Luminescence) element as a self light emitting element can be applied in general, and is not limited thereto.

  The light emitting element group HS2 has a light emission voltage Vh2 as a second light emission voltage based on the drive voltage Vk as a second light emission reference voltage VH2 which is higher than the light emission reference voltage VH1 and is the other end of itself. When the light emitting current Ih2 as the second light emitting current is applied to the anode of the light emitting element HS2a and flows to each of the light emitting elements HS2a, light is emitted. Note that the current value of the light emission current Ih2 is determined based on the resistance value of the resistance element Rh2. Further, each of the light emitting elements HS2a has an internal resistance, and the forward voltage per light emitting element HS2a is 2 V, for example.

  Here, in the present embodiment, the light emission reference voltage VH2 for the light emitting element group HS2 to emit light includes four light emitting elements HS2a having a forward voltage of 2V in which the light emitting element groups HS2 are connected in series. For example, 8V. That is, in order for the light emitting element group HS2 to emit light, the light emission voltage Vh2 applied to the anode of the light emitting element HS2a at the other end needs to be 8V or more.

  Here, “the anode of the light emitting element HS2a as the other end of the light emitting element group HS2” is referred to as a node Nh2, and “the cathode of the light emitting element HS2a as one end of the light emitting element group HS2” is referred to as a node Nh2a. Further, “the light emission current Ih2 flows through each of the light emitting elements HS2a” is described as “the light emission current Ih2 flows through the light emitting element group HS2.”

  Here, in the present embodiment, in order for the light emitting element group HS to emit light without variation inside, in other words, for the light emitting element group HS1 and the light emitting element group 2 to emit light simultaneously, the light emission reference voltage VH2 which is 8V. Since the voltage is higher than the light emission reference voltage VH1 which is 6V, a voltage larger than the light emission reference voltage VH2 which is 8V needs to be applied to the light emitting element group HS as the light emission voltage Vh. Here, a voltage for causing the light emitting element group HS to emit light without variation therein is referred to as a light emission reference voltage VH. The light emitting element group HS emits light when a light emission voltage Vh equal to or higher than the light emission reference voltage VH based on the light emission reference voltage VH2 is applied. In the present embodiment, the light emission reference voltage VH is 8 V, which is the same as the light emission reference voltage VH2.

  In the present embodiment, the example in which the light emitting element group HS2 includes more light emitting elements HS2a than the number of light emitting elements HS1a provided in the light emitting element group HS1 has been described, but the present invention is not limited thereto. That is, the illumination device 10 according to the present invention is remarkable when the light emission reference voltage VH1 necessary for the light emitting element group HS1 to emit light and the light emission reference voltage VH2 necessary for the light emitting element group HS2 to emit light are different. This does not prevent the number of light emitting elements included in the light emitting element group HS1 and the light emitting element group HS2 from being the same. Similarly, the light emitting element group HS1 and the light emitting element group HS2 may include one LED.

  Here, if a light emission voltage Vh not lower than the light emission reference voltage VH1 and not higher than the light emission reference voltage VH2 is applied to the light emitting element group HS without any control, the light emitting element group HS1 emits light, and the light emitting element group HS2 does not emit light. Further, when the light emission voltage Vh that is equal to or higher than the light emission reference voltage VH2 is applied to the light emitting element group HS, the light emitting element group HS2 emits light in addition to the light emitting element group HS1. That is, when a light emission voltage Vh lower than the reference voltage VH2 is applied to the light emitting element group HS, the light emission timings of the light emitting element group HS1 and the light emitting element group HS2 vary, and the light emission as a whole of the light emitting element group HS is disturbed. There is a risk that. In particular, when used in an in-vehicle exterior lamp, disturbance of light emission of the light emitting element group may lead to an accident. In the illumination device 10 according to the present invention, such a problem is prevented from occurring.

  The light emission control unit HC includes a comparison circuit CN as a first comparison circuit, and a transistor P1 as a first control switch.

  The comparison circuit CN includes a resistance element R1, a resistance element R2, a reference power source Ref1, and a comparator Cp1.

  One end of the resistance element R1 is connected to the power supply circuit VS, and the resistance value is, for example, 400Ω. Here, the connection point between the resistance element R1, in other words, the comparison circuit CN and the power supply circuit VS is referred to as a node Nd1. One end of the resistance element R2 is connected to the other end of the resistance element R1, the other end is connected to the power source VSS, and the resistance value is, for example, 200Ω. Here, a connection point between the other end of the resistance element R1 and one end of the resistance element R2 is referred to as a node Nd2, and a potential of the node Nd2 is referred to as a comparison voltage Vc. The potential of the node Nd2 is a potential obtained by dividing the drive voltage Vk by the resistance element R1 and the resistance element R2.

  One end of the reference power source Ref1 is connected to the power source VSS, and generates a reference voltage Vref1 as a first reference voltage. The reference voltage Vref1 is set to be equal to or higher than a voltage value obtained when the light emission reference voltage VH is divided by the resistance element R1 and the resistance element R2. That is, the reference voltage Vref1 is set based on the light emission reference voltage VH. In this embodiment, the reference voltage Vref1 is set to, for example, 3V, which is higher than 2.6V obtained by dividing 8V, which is the light emission reference voltage VH, by the resistance element R1 of 400Ω and the resistance element R2 of 200Ω.

  In the comparator Cp1, the node Nd2 is connected to the inverting terminal and the comparison voltage Vc is input, and the other end of the reference power source Ref1 is connected to the non-inverting terminal and the reference voltage Vref1 is input. The comparator Cp1 compares the comparison voltage Vc with the reference voltage Vref1, and outputs a comparison result signal Vcr1 from the output terminal as the comparison result. For example, when the comparison voltage Vc is smaller than the reference voltage Vref1, the comparator Cp1 outputs a high-level comparison result signal Vcr1 at almost the same voltage level as the drive voltage Vk, and the comparison voltage Vc is larger than the reference voltage Vref1. For example, the low-level comparison result signal Vcr1 is output at 0V.

  As described above, the comparison circuit CN is connected to the power supply circuit VS, determines whether the drive voltage Vk is larger or smaller than the voltage based on the light emission reference voltage VH, and outputs the result as the comparison result signal Vcr1. .

  The transistor P1 is a PMOS transistor, the source terminal S is connected to the power supply circuit VS, the drain terminal D is connected to the nodes Nh1 and Nh2, and the gate terminal G as a control terminal is the output terminal of the comparator Cp1, in other words It is connected to the comparison circuit CN. The transistor P1 is controlled to be turned on / off by a comparison result signal Vcr1 output from the comparison circuit CN and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS.

  Note that a connection point between the drain terminal D of the transistor P1 and the nodes Nh1 and Nh2 is referred to as a node Nd3. The light emitting element group HS1 and the light emitting element group HS2 are connected in parallel to each other at a node Nd3 that is a connection point with the drain terminal D of the transistor P1.

  The transistor P1 is turned off when the high-level comparison result signal Vcr1 output from the comparison circuit CN is input to the gate terminal G. In this case, the potential at the node Nd3 becomes 0V, and thereby the light emission voltage Vh becomes 0V. For this reason, when the light emission voltage Vh1 applied to the light emitting element group HS1 is 0V, the light emission current Ih1 flowing through the light emitting element group HS1 is stopped and becomes 0A, so the light emitting element group HS1 does not emit light. Further, since the light emission voltage Vh2 applied to the light emitting element group HS2 is 0V and the light emission current Ih2 flowing through the light emitting element group HS2 is 0A, the light emitting element group HS2 does not emit light.

  The transistor P1 is turned on when the low-level comparison result signal Vcr1 output from the comparison circuit CN is input to the gate terminal G. In this case, the potential at the node Nd3 is 9 V or more, for example, and the light emission voltage Vh is 9 V or more. For this reason, the light emitting element group HS1 emits light by applying a light emission voltage Vh1 higher than 6 V, which is the light emission reference voltage VH1, to the light emitting element group HS1 and causing the light emission current Ih1 to flow. In addition, the light emitting element group HS2 emits light when a light emitting voltage Vh2 higher than the light emission reference voltage VH2 of 8V is applied to the light emitting element group HS2 and a light emitting current Ih2 flows.

  As described above, the light emission control unit HC detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH, and when the drive voltage Vk is larger than the light emission reference voltage VH, the transistor P1 is turned on to emit light current. When the light emission control for causing the light emitting element group HS to emit light is performed by making it possible to supply Ih1 to the light emitting element group HS1 and supplying the light emission current Ih2 to the light emitting element group HS2, and the drive voltage Vk is smaller than the light emission reference voltage VH The light emission stop control is performed to stop the light emission of the light emitting element group HS by turning off the transistor P1 so that the light emission current Ih1 cannot be supplied to the light emitting element group HS1 and the light emission current Ih2 cannot be supplied to the light emitting element group HS2. Do. For this reason, according to the illuminating device 10 concerning this embodiment, the light emitting element group HS1 and the light emitting element group HS2 can be light-emitted and light-extinguished simultaneously.

  FIG. 2 is a diagram showing the transition of each signal waveform from the rise to the fall of the power supply for driving the illumination device 10. FIG. 2A shows the transition of the drive voltage Vk over time. FIG. 2B shows the relationship between the transition of the comparison voltage Vc and the reference voltage Vref1 over time. FIG. 2C shows the transition of the comparison result signal Vcr1 over time. FIG. 2D shows the transition of the light emission voltage Vh over time. FIG. 2E shows the transition of the light emission current Ih1 and the light emission current Ih2 over time. 2A to 2D, the vertical axis represents voltage V and the horizontal axis represents time t. In FIG. 2E, the vertical axis represents current I, the horizontal axis represents time t, and time t0. ~ T4 is shown as a common time in FIGS. 2 (a) to 2 (e).

  At time t0, driving of the power source for driving the lighting device 10 is started, and the voltage level of the driving voltage Vk output from the power supply circuit VS starts to increase. At this time, since the comparison voltage Vc obtained by dividing the drive voltage Vk is 3V or less of the reference voltage Vref1, the comparison result signal Vcr1 is substantially at the same level as the drive voltage Vk, and the transistor P1 is turned off. It has become. For this reason, the light emission voltage Vh output from the transistor P1 is 0 V, the light emission current Ih1 does not flow through the light emitting element group HS1, and the light emission current Ih2 does not flow through the light emitting element group HS2. . That is, at the time t0, the light emitting element group HS is in an extinguished state.

  When the drive voltage Vk becomes 9V at time t1, the comparison voltage Vc becomes 3V, which is equal to or higher than 3V of the reference voltage Vref1, so that the comparison result signal Vcr1 transitions to a low level. Thereby, the transistor P1 is turned on and the light emission voltage Vh is output at about 9V. At this time, since the light emission voltage Vh1 of about 9V applied to the light emitting element group HS1 is larger than 6V which is the light emission reference voltage VH1, the light emission current Ih1 flows through the light emitting element group HS1 to emit light. Further, since the light emission voltage Vh2 of about 9V applied to the light emitting element group HS2 is higher than the light emission reference voltage VH2, which is 8V, the light emission current Ih2 flows through the light emitting element group HS2 to emit light. That is, the light emitting element group HS1 and the light emitting element group HS2 emit light without variation at the same timing.

  When driving of the power source for driving the illumination device 10 is stopped at time t2, the drive voltage Vk starts to decrease. At this time, the light emission voltage Vh, the light emission current Ih1, and the light emission current Ih2 output from the transistor P1 based on the comparison voltage Vc, the light emission voltage Vh, and the drive voltage Vk obtained by dividing the drive voltage Vk also start to decrease.

  When the lowered drive voltage Vk becomes less than 9V at time t3, the comparison voltage Vc becomes less than 3V. As a result, the comparison result signal Vcr1 transits to substantially the same level as the drive voltage Vk, the transistor P1 is turned off, and the output of the light emission voltage Vh, the light emission current Ih1, and the light emission current Ih2 from the transistor P1 is stopped. Thereby, the supply of the light emission current Ih1 to the light emitting element group HS1 and the supply of the light emission current Ih2 to the light emitting element group HS2 are stopped, and the light emitting element group HS1 and the light emitting element group HS2 are turned off simultaneously. At this time, since the transistor P1 is turned off when the light emission voltage Vh is higher than 8V which is the light emission reference voltage VH2, the light emitting element group HS1 and the light emitting element group HS2 do not vary and turn off at different timings. .

  At time t4, the drive voltage Vk decreases to 0V. Thereby, the drive of the illuminating device 10 will be in a halt condition.

  As described above, according to the lighting device 10 according to the first embodiment of the present invention, the light emission control unit HC detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH, and the drive voltage Vk is greater than the light emission reference voltage VH. If the drive voltage Vk is lower than the light emission reference voltage VH, light emission stop control is performed to stop the light emission of the light emitting element group HS. For this reason, it is possible to prevent variations in the timing of light emission and extinction between the light emitting element group HS1 and the light emitting element group HS2.

[First Modification of First Embodiment]
FIG. 3 is a diagram showing an illuminating device 10a according to a first modification of the first embodiment of the present invention. The illumination device 10a includes a power supply circuit VS, a light emitting element group HS, a light emission control unit HC, a light control circuit LC1 as a first light control unit, and a light control circuit LC2 as a second light control unit. It is equipped with. The illumination device 10a according to the present modification is substantially different from the illumination device 10 shown in FIG. 1 in that it newly includes a dimming circuit LC1 and a dimming circuit LC2. In the lighting device 10a shown in FIG. 3, the same components as those of the lighting device 10 shown in FIG.

  The dimming circuit LC1 has one end connected to the node Nd3, that is, the drain terminal D of the transistor P1, and the other end connected to the node Nh1. In other words, the node Nh1 is connected to the node Nd3 via the dimming circuit LC1. The light control circuit LC1 adjusts the light emission current Ih1 flowing through the light emitting element group HS1 to a predetermined current value, and thereby adjusts the light emission luminance of the light emitting element group HS1. Here, the transistor P1 supplies the driving voltage Vk to the dimming circuit LC1 when turned on, and stops supplying the driving voltage Vk to the dimming circuit LC1 when turned off.

  The dimming circuit LC1 may be configured to adjust the amount of current flowing through the light emitting element group HS1 based on the value of the current flowing through the light emitting element group HS1. It is good also as a structure which flows into group HS1, and it is not restricted to these, Various structures are applicable. Moreover, since the illuminating device 10a includes the dimming circuit LC1, the current value of the light emission current Ih1 that flows through the light emitting element group HS1 in the dimming circuit LC1 without using the resistive element Rh1 or together with the resistive element Rh1. It may be decided. In the lighting device 10a according to the present embodiment, the configuration in which the dimming circuit LC1 is connected between the node Nd3 and the node Nh1 has been described. However, the configuration is not limited thereto, and the dimming circuit LC1 includes the node Nh1a. And the power supply VSS.

  The dimming circuit LC2 has one end connected to the node Nd3, that is, the drain terminal D of the transistor P1, and the other end connected to the node Nh2. In other words, the node Nh2 is connected to the node Nd3 via the dimming circuit LC2. Thereby, the light control circuit LC2 and the light emitting element group HS2 connected in series with each other are connected in parallel with each other at the node Nd3 with the light control circuit LC1 and the light emitting element group HS1 connected in series with each other. The light control circuit LC2 adjusts the light emission current Ih2 flowing through the light emitting element group HS2 to a predetermined current value, thereby adjusting the light emission luminance of the light emitting element group HS2. Here, the transistor P1 supplies the driving voltage Vk to the dimming circuit LC2 when turned on, and stops supplying the driving voltage Vk to the dimming circuit LC2 when turned off.

  The dimming circuit LC2 may be configured to adjust the amount of current flowing through the light emitting element group HS2 based on the value of the current flowing through the light emitting element group HS2, or a predetermined current amount may be adjusted in advance by PWM control. It is good also as a structure which flows into group HS2, and it is not restricted to these, Various structures are applicable. Moreover, since the illuminating device 10a includes the dimming circuit LC2, the current value of the light emission current Ih2 flowing through the light emitting element group HS2 in the dimming circuit LC2 without using the resistive element Rh2 or together with the resistive element Rh2 is determined. It may be decided. In the lighting device 10a according to the present embodiment, the configuration in which the dimming circuit LC2 is connected between the node Nd3 and the node Nh2 has been described. However, the configuration is not limited thereto, and the dimming circuit LC2 includes the node Nh2a. And the power supply VSS.

[Second Modification of First Embodiment]
FIG. 4 is a view showing an illuminating device 10b according to a second modification of the first embodiment of the present invention. The illumination device 10b includes a power supply circuit VS, a light emitting element group HS, a dimming circuit LC1, a dimming circuit LC2, and a light emission control unit HCa. The illumination device 10b according to the present modification is substantially different from the illumination device 10a shown in FIG. 3 in that a light emission control unit HCa is provided instead of the light emission control unit HC. In the illumination device 10b shown in FIG. 4, the same components as those in the illumination device 10 shown in FIG. 1 or the illumination device 10a shown in FIG.

  The dimming circuit LC1 is configured such that one end is connected to the node Nd1 and is thereby connected to the power supply circuit VS. The light control circuit LC1 adjusts the light emission current Ih1 flowing through the light emitting element group HS1 so as to have a predetermined current value.

  The dimming circuit LC2 is configured such that one end is connected to the node Nd1 and is thereby connected to the power supply circuit VS. The light control circuit LC2 adjusts the light emission current Ih2 flowing through the light emitting element group HS2 so as to have a predetermined current value.

  The light emission control unit HCa includes a comparison circuit CN, a transistor P2 as a first control switch, and a transistor P3 as a second control switch.

  The transistor P2 is a PMOS transistor, the source terminal S is connected to the other end of the dimming circuit LC1, the drain terminal D is connected to the node Nh1, and the gate terminal G as a control terminal is connected to the comparison circuit CN. . The transistor P2 is controlled to be turned on / off by a comparison result signal Vcr1 output from the comparison circuit CN and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS. When the transistor P2 is turned on, the drive voltage Vk supplied from the power supply circuit VS to the source terminal S via the dimming circuit LC1 is output from the drain terminal D as the light emission voltage Vh1.

  The transistor P2 is turned off when the high-level comparison result signal Vcr1 output from the comparison circuit CN is input to the gate terminal G. In this case, the light emission voltage Vh1 applied to the light emitting element group HS1 is 0V, and the light emission current Ih1 supplied to the light emitting element group HS1 is 0A. That is, the supply of the light emission current Ih1 to the light emitting element group HS1 is stopped. The light emitting element group HS1 does not emit light. The transistor P2 is turned on when the low-level comparison result signal Vcr1 output from the comparison circuit CN is input to the gate terminal G. In this case, the light emission voltage Vh1 applied to the light emitting element group HS1 is 9 V or higher, which is higher than the light emission reference voltage VH1. For this reason, the light emitting voltage Vh1 higher than 6V which is the light emission reference voltage VH1 is applied to the light emitting element group HS1, and the light emission current Ih1 is supplied and flows. Thereby, the light emitting element group HS1 emits light.

  The transistor P3 is a PMOS transistor, the source terminal S is connected to the other end of the dimming circuit LC2, the drain terminal D is connected to the node Nh2, and the gate terminal G as a control terminal is connected to the comparison circuit CN. . The transistor P3 is controlled to be turned on / off by the comparison result signal Vcr1 output from the comparison circuit CN and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS. When the transistor P3 is turned on, the drive voltage Vk supplied from the power supply circuit VS to the source terminal S via the dimming circuit LC2 is output from the drain terminal D as the light emission voltage Vh2.

  The transistor P3 is turned off when the high-level comparison result signal Vcr1 output from the comparison circuit CN is input to the gate terminal G. In this case, the light emission voltage Vh2 applied to the light emitting element group HS1 is 0V, and the light emission current Ih2 supplied and flowing to the light emitting element group HS2 is 0A. That is, the supply of the light emission current Ih2 to the light emitting element group HS2 is stopped. The light emitting element group HS2 does not emit light. The transistor P3 is turned on when the low-level comparison result signal Vcr1 output from the comparison circuit CN is input to the gate terminal G. In this case, the light emission voltage Vh2 applied to the light emitting element group HS2 is 9 V or higher, which is higher than the light emission reference voltage VH2. For this reason, a light emission voltage Vh2 higher than 8V, which is the light emission reference voltage VH2, is applied to the light emitting element group HS2 to supply and flow a light emission current Ih2. Thereby, the light emitting element group HS2 emits light.

  Here, the light control circuit LC1 and the light emitting element group HS1 connected in series with each other are connected in parallel with each other in the light control circuit LC2 and the light emitting element group HS2 connected in series with each other in the power supply circuit VS.

  As described above, the light emission control unit HCa detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH. When the drive voltage Vk is larger than the light emission reference voltage VH, the light emission current is controlled by turning on the transistor P2. Ih1 can be supplied to the light emitting element group HS1, and the transistor P3 is turned on so that the light emission current Ih2 can be supplied to the light emitting element group HS2, thereby performing light emission control for causing the light emitting element group HS to emit light. When the voltage is lower than the voltage VH, the transistor P2 is turned off so that the light emission current Ih1 cannot be supplied to the light emitting element group HS1, and the transistor P3 is turned off so that the light emission current Ih2 cannot be supplied to the light emitting element group HS2. Light emission stop control for stopping the light emission of the element group HS is performed. For this reason, according to the illuminating device 10b concerning this embodiment, the light emitting element group HS1 and the light emitting element group HS2 can be light-emitted and light-extinguished simultaneously.

  The illumination device 10b according to the second modification of the first embodiment of the present invention includes the transistor P2 and the transistor P3 instead of the transistor P1 in the illumination device 10, and thus emits the light emitting element group HS1. The light emitting current Ih1 that flows to the light emitting element group HS1 to cause the light emitting element group HS2 to emit light and the light emitting current Ih2 that flows to the light emitting element group HS2 to cause the light emitting element group HS2 to emit light are emitted from the power supply circuit VS via different transistors. And the light emitting element group HS2. For this reason, the current concentrated on the transistor P1 in the lighting device 10 can be distributed to the transistor P2 and the transistor P3, so that local concentration of heat in the lighting device can be prevented. Needless to say, this effect increases in proportion to an increase in the number of light emitting elements included in the light emitting element group HS and the number of light emitting element groups connected in parallel to each other.

[Second Embodiment]
FIG. 5 is a view showing an illumination device 20 according to the second embodiment of the present invention. The lighting device 20 includes a power supply circuit VS, a light emitting element group HS, and a light emission control unit HCb. The illumination device 20 according to the present embodiment is substantially different from the illumination device 10 shown in FIG. 1 in that a light emission control unit HCb is provided instead of the light emission control unit HC. In the illuminating device 20 shown in FIG. 5, the same components as those in the illuminating device 10 shown in FIG.

  The other end of the light emitting element group HS1 is connected to the power supply circuit VS. The other end of the light emitting element group HS2 is connected to the power supply circuit VS. Thereby, each light emitting element HS1a of the light emitting element group HS1 and each light emitting element HS2a of the light emitting element group HS2 are connected in parallel to each other in the power supply circuit VS. The light emitting element group HS1 in the lighting device 20 includes a resistance element Rh3 having one end connected to the power supply circuit VS and the other end connected to the node Nh1, instead of the resistance element Rh1 of the lighting device 10. The light emission current Ih1 is determined based on the resistance values of the light emitting elements HS1a and the resistance element Rh3. The light emitting element group HS2 in the lighting device 20 includes a resistance element Rh4 having one end connected to the power supply circuit VS and the other end connected to the node Nh2, instead of the resistance element Rh2 of the lighting device 10. The light emission current Ih2 is determined based on the resistance values of the light emitting elements HS2a and the resistance element Rh4. Further, the resistance value of the resistance element Rh3 is larger than the resistance value of the resistance element Rh4, and the voltage determined by the internal resistance of the light emitting element HS1a, the series resistance value of the resistance element Rh3, and the light emission current Ih1 is internal to the light emitting element HS2a. The voltage is determined to be the same as the voltage determined by the series resistance value of the resistor and the resistor element Rh4 and the light emission current Ih2. Thus, the light emission current Ih1 flowing through the light emitting element group HS1 and the light emission current Ih2 flowing through the light emitting element group HS2 are made the same so that the light emission luminances of the light emitting element group HS1 and the light emitting element group HS2 are the same. Has been. However, when it is not necessary to make the light emission luminances of the light emitting element group HS1 and the light emitting element group HS2 the same, the resistance value of the resistance element Rh3 does not necessarily need to be larger than the resistance value of the resistance element Rh4.

  The light emission control unit HCb includes a comparison circuit CNa as a first comparison circuit, a transistor N1 as a first control switch, and a transistor N2 as a second control switch.

  The comparison circuit CNa includes a resistance element R1, a resistance element R2, a reference power source Ref1, and a comparator Cp2. Since the connection point between the resistance element R1 and the power supply circuit VS is Nd1, in this embodiment, the node Nd1 is, in other words, the connection point between the comparison circuit CNa and the power supply circuit VS.

  In the comparator Cp2, the node Nd2 is connected to the non-inverting terminal and the comparison voltage Vc is input, and the other end of the reference power source Ref1 is connected to the inverting terminal and the reference voltage Vref1 is input. The comparator Cp2 compares the comparison voltage Vc with the reference voltage Vref1, and outputs a comparison result signal Vcr2 from the output terminal as a comparison result. When the comparison voltage Vc is smaller than the reference voltage Vref1, the comparator Cp2 outputs a low-level comparison result signal Vcr2 at, for example, 0V, and when the comparison voltage Vc is larger than the reference voltage Vref1, for example, the driving voltage Vk. A high-level comparison result signal Vcr2 is output at substantially the same voltage level.

  As described above, the comparison circuit CNa is connected to the power supply circuit VS, determines whether the drive voltage Vk is larger or smaller than the voltage based on the light emission reference voltage VH, and outputs the result as the comparison result signal Vcr2. .

  The transistor N1 is an NMOS transistor, the gate terminal G as a control terminal is connected to the output terminal of the comparator Cp2, in other words, the comparison circuit CNa, the drain terminal D is connected to the node Nh1a, and the source terminal S is connected to the power supply VSS. Has been. In other words, the node Nh1a is connected to the power supply VSS via the transistor N1. The transistor N1 is controlled to be turned on / off by a comparison result signal Vcr2 output from the comparison circuit CNa and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS1.

  The transistor N1 is turned off when the low-level comparison result signal Vcr2 output from the comparison circuit CNa is input to the gate terminal G. In this case, the light emitting current Ih1 flowing through the light emitting element group HS1 is stopped and becomes 0A, that is, the supply of the light emitting current Ih1 to the light emitting element group HS1 is stopped, and thus the light emitting element group HS1 does not emit light. The transistor N1 is turned on when the high-level comparison result signal Vcr2 output from the comparator Cp2 is input to the gate terminal G. In this case, since the light emitting voltage Vh1 higher than the reference voltage VH1 is applied to the light emitting element group HS1, the light emitting current Ih1 flows through the light emitting element group HS1. Thereby, the light emitting element group HS1 emits light.

  The transistor N2 is an NMOS transistor, the gate terminal G as a control terminal is connected to the output terminal of the comparator Cp2, in other words, the comparison circuit CNa, the drain terminal D is connected to the node Nh2a, and the source terminal S is connected to the power supply VSS. Has been. In other words, the node Nh2a is connected to the power supply VSS via the transistor N2. The transistor N2 is controlled to be turned on / off by a comparison result signal Vcr2 output from the comparison circuit CNa and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS2.

  The transistor N2 is turned off when the low-level comparison result signal Vcr2 output from the comparison circuit CNa is input to the gate terminal G. In this case, the light emitting current Ih2 flowing through the light emitting element group HS2 is stopped and becomes 0A, that is, the supply of the light emitting current Ih2 to the light emitting element group HS2 is stopped, and thus the light emitting element group HS2 does not emit light. The transistor N2 is turned on when the high-level comparison result signal Vcr2 output from the comparator Cp2 is input to the gate terminal G. In this case, since the light emission voltage Vh2 higher than the reference voltage VH1 is applied to the light emitting element group HS2, the light emission current Ih2 flows through the light emitting element group HS2. Thereby, the light emitting element group HS2 emits light.

  As described above, the light emission control unit HCb detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH. When the drive voltage Vk is larger than the light emission reference voltage VH, the light emission current is turned on. Ih1 can be supplied to the light emitting element group HS1, and the transistor N2 is turned on to enable the light emission current Ih2 to be supplied to the light emitting element group HS2, thereby performing light emission control for causing the light emitting element group HS to emit light. When the voltage is lower than the voltage VH, the transistor N1 is turned off so that the light emission current Ih1 cannot be supplied to the light emitting element group HS1, and the transistor N2 is turned off so that the light emission current Ih2 cannot be supplied to the light emitting element group HS2. Light emission stop control for stopping the light emission of the element group HS is performed. For this reason, according to the illuminating device 20 concerning this embodiment, the light emitting element group HS1 and the light emitting element group HS2 can be light-emitted and light-extinguished simultaneously.

  Note that the lighting device 20 performs light emission control and light emission stop control by controlling on / off of the transistor N1 connected to the node Nh1a and the power supply VSS and the transistor N2 connected to the node Nh2a and the power supply VSS. Therefore, as in the illumination devices 10, 10a, and 10b according to the first embodiment, the PMOS transistors for performing the light emission control and the light emission stop control are provided with the power supply circuit VS, the light emitting element group HS1, and the light emitting element group HS2. There is no need to connect between. Therefore, the light emission voltage Vh1 based on the drive voltage Vk output from the power supply circuit VS can be supplied to the light emitting element group HS1 without causing a voltage drop, and the light emission voltage Vh2 can be supplied without causing a voltage drop. The light can be supplied to the light emitting element group HS2. Therefore, the light emitting element group HS1 and the light emitting element group HS2 can be made to emit light at a lower drive voltage Vk.

  The lighting device 20 performs light emission control and light emission stop control by controlling on / off of the transistor N1 connected to the node Nh1a and the power supply VSS and the transistor N2 connected to the node Nh2a and the power supply VSS. Therefore, unlike the lighting devices 10, 10 a, and 10 b according to the first embodiment, it is not necessary to use a PMOS transistor to perform light emission control and light emission stop control. That is, since the light emission control and the light emission stop control are performed by the NMOS transistor that can realize the equivalent driving capability in a smaller size than the PMOS transistor, compared with the illumination devices 10, 10a, and 10b according to the first embodiment. Thus, the area of the lighting device can be reduced.

  FIG. 6 is a diagram illustrating the transition of each signal waveform from the rise to the fall of the power supply for driving the lighting device 20. FIG. 6A shows the transition of the drive voltage Vk over time. FIG. 6B shows the relationship between the transition of the comparison voltage Vc and the reference voltage Vref1 over time. FIG. 6C shows the transition of the comparison result signal Vcr2 over time. FIG. 6D shows transition of the light emission voltage Vh1 and the light emission voltage Vh2 over time. FIG. 6E shows the transition of the light emission current Ih1 and the light emission current Ih2 over time. 6A to 6D, the vertical axis represents voltage V and the horizontal axis represents time t. In FIG. 6E, the vertical axis represents current I, the horizontal axis represents time t, and time t10. ~ T14 is shown as a common time in FIGS. 6 (a) to 6 (e). Further, in FIG. 6E, the light emission current Ih1 and the light emission current Ih2 are shown as the same current value, but the present invention is not limited to this. In FIG. 6, the signal waveforms described in FIG. 2 according to the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  At time t10, driving of the power source for driving the lighting device 20 is started, and the drive voltage Vk starts to rise. At this time, since the comparison voltage Vc is 3 V or less of the reference voltage Vref1, the comparison result signal Vcr2 is at a low level. Further, since the comparison result signal Vcr2 is at the low level, the transistor N1 and the transistor N2 are turned off, the light emitting current Ih1 does not flow through the light emitting element group HS1, and the light emitting current Ih2 flows through the light emitting element group HS2. Is in a state that does not flow. That is, at time t10, the light emitting element group HS is in an extinguished state.

  At time t11, the comparison voltage Vc becomes equal to or higher than the reference voltage Vref1, the comparison result signal Vcr2 changes to high level, and the transistors N1 and N2 are turned on. At this time, since the light emission voltage Vh1 and the light emission voltage Vh2 are about 9 V, the light emission current Ih1 flows to the light emitting element group HS1, the light emitting element group HS1 emits light, and the light emission current Ih2 flows to the light emitting element group HS2. The light emitting element group HS2 emits light. That is, all the light emitting elements HS1a in the light emitting element group HS1 and all the light emitting elements HS2a in the light emitting element group HS2 emit light without variation at the same timing.

  When the drive of the power source for driving the lighting device 20 is stopped at time t12, the drive voltage Vk starts to decrease. At this time, the comparison voltage Vc, the light emission voltage Vh1, the light emission current Ih1, the light emission voltage Vh2, and the light emission current Vh3 also start to decrease.

  At time t13, the lowered drive voltage Vk becomes less than 9V and the comparison voltage Vc becomes less than 3V. As a result, the comparison result signal Vcr2 transits to a low level, the transistor N1 and the transistor N2 are turned off, and the light emission current Ih1 flowing through the light emitting element group HS1 and the light emission current Ih2 flowing through the light emitting element group HS2 are stopped. HS1 and the light emitting element group HS2 are turned off simultaneously. At this time, the transistor N1 and the transistor N2 are turned off when the light emission voltage Vh1 and the light emission voltage Vh2 are higher than the reference voltage VH2, which is 8 V. Therefore, the light emitting element group HS1 and the light emitting element group HS2 vary at different timings. Will not turn off.

  At time t14, the drive voltage Vk decreases to 0V. Thereby, the drive of the illuminating device 20 will be in a halt condition.

  As described above, according to the illumination device 20 according to the second embodiment of the present invention, the light emission control unit HCb detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH, and the drive voltage Vk is greater than the light emission reference voltage VH. If the drive voltage Vk is lower than the light emission reference voltage VH, light emission stop control is performed to stop the light emission of the light emitting element group HS. For this reason, it is possible to prevent variations in the timing of light emission and extinction between the light emitting element group HS1 and the light emitting element group HS2.

[First Modification of Second Embodiment]
FIG. 7 is a diagram showing a lighting device 20a according to a first modification of the second embodiment of the present invention. The illumination device 20a includes a power supply circuit VS, a light emitting element group HS, a light emission control unit HCb, a dimming circuit LC1, and a dimming circuit LC2. The illuminating device 20a according to the present modification is substantially different from the illuminating device 20 shown in FIG. 5 in that it newly includes a dimming circuit LC1 and a dimming circuit LC2. In addition, in the illuminating device 20a shown in FIG. 7, the same code | symbol is attached about the structure similar to the illuminating device 10a shown in FIG. 3, the illuminating device 10b shown in FIG. 4, or the illuminating device 20 shown in FIG. The description will be omitted as appropriate.

  One end of the dimming circuit LC1 is connected to the node Nd1, and thereby connected to the power supply circuit VS. The other end of the dimming circuit LC1 is connected to the node Nh1. In other words, the node Nh1 is connected to the node Nd1 via the dimming circuit LC1 and the node Nd1. The light control circuit LC1 adjusts the light emission current Ih1 flowing through the light emitting element group HS1 so as to have a predetermined current value.

  In the illumination device 20a according to the present embodiment, the configuration in which the dimming circuit LC1 is connected between the node Nd1 and the node Nh1 has been described. However, the configuration is not limited thereto, and the dimming circuit LC1 includes the node Nh1a. And the power supply VSS.

  One end of the dimming circuit LC2 is connected to the node Nd1, and thereby connected to the power supply circuit VS. The other end of the dimming circuit LC2 is connected to the node Nh2. In other words, the node Nh2 is connected to the node Nd1 via the dimming circuit LC2 and the node Nd1. Thereby, the light control circuit LC2 and the light emitting element group HS2 connected in series with each other are connected in parallel with each other at the node Nd1 with the light control circuit LC1 and the light emitting element group HS1 connected in series with each other. The light control circuit LC2 adjusts the light emission current Ih2 flowing through the light emitting element group HS2 to a predetermined current value.

  In the illumination device 20a according to the present embodiment, the configuration in which the dimming circuit LC2 is connected between the node Nd2 and the node Nh2 has been described. However, the configuration is not limited thereto, and the dimming circuit LC2 includes the node Nh2a. And the power supply VSS.

[Third Embodiment]
FIG. 8 is a view showing an illumination device 30 according to the third embodiment of the present invention. The illumination device 30 includes a power supply circuit VS, a light emitting element group HS, a light control circuit LC1, a light control circuit LC2, and a light emission control unit HCc. The illumination device 30 according to the present embodiment is substantially different from the illumination device 10a shown in FIG. 3 in that a light emission control unit HCc is provided instead of the light emission control unit HC. Compared with the illumination device 10b shown, the light emission control unit HCc is substantially different from the illumination device 10b in that a light emission control unit HCc is provided. Compared with the illumination device 20a shown in FIG. This is substantially different in that a light emission control unit HCc is provided instead of HCb. In the lighting device 30 shown in FIG. 8, the same components as those in the lighting device 10a shown in FIG. 3, the lighting device 10b shown in FIG. 4, or the lighting device 20a shown in FIG. A description thereof will be omitted as appropriate.

  One end of the dimming circuit LC1 is connected to the node Nd1, thereby connecting to the power supply circuit VS. The other end of the dimming circuit LC1 is connected to the node Nh1. In other words, the node Nh1 is connected to the power supply circuit VS via the dimming circuit LC1 and the node Nd1. The light control circuit LC1 adjusts the light emission current Ih1 flowing through the light emitting element group HS1 to a predetermined current value, and thereby adjusts the light emission luminance of the light emitting element group HS1. The dimming circuit LC1 includes a transistor P4 as a first dimming switch and a comparison circuit CNL1 as a first dimming comparison circuit.

  The comparison circuit CNL1 includes a resistance element R3, a reference power supply Ref2, and a comparator Cp3.

  One end of the resistance element R3 is connected to the power supply circuit VS, and the resistance value is, for example, 400Ω.

  One end of the reference power supply Ref2 is connected to the power supply circuit VS and one end of the resistance element R3, and outputs a reference voltage Vref2 as a first dimming reference voltage. The reference power supply Ref2 outputs the drive voltage Vk as a reference voltage Vref2 at a potential that is lowered by a predetermined potential.

  In the comparator Cp3, the other end of the resistor element R3 is connected to the inverting terminal, and the feedback voltage Vfb1 as the first dimming comparison voltage, which is the potential of the resistor element R3, is input, and the non-inverting terminal of the reference power supply Ref2 is input. The other end is connected and the reference voltage Vref2 is input. The comparator Cp3 compares the feedback voltage Vfb1 with the reference voltage Vref2, and outputs a comparison result signal Vcr3 as a first control signal from the output terminal as the comparison result. Here, a connection point between the other end of the resistance element R3 and the inverting terminal of the comparator Cp3 is referred to as a node Nd4. The voltage level of the feedback voltage Vfb1 is determined based on the light emission voltage Vh1.

  The transistor P4 is a PMOS transistor, and the source terminal S is connected to the node Nd4 which is the other end of the resistor element R3 and is the non-inverting terminal of the comparator Cp3. In other words, the transistor P4 is connected to the power supply circuit VS via the resistor element R3. The drain terminal D is connected to the node Nh1. The transistor P4 generates and outputs the drive voltage Vk, the light emission voltage Vh1, and the light emission current Ih1 supplied to the source terminal S from the power supply circuit VS via the resistance element R3.

  Here, the comparator Cp3 compares the feedback voltage Vfb1 with the reference voltage Vref2, and based on the comparison result, the comparison result is applied to the gate terminal G of the transistor P4 so that the potential of the node Nd4 becomes the same level as the reference voltage Vref2. The signal Vcr3 is supplied to adjust the output level of the light emission current Vh1 output from the transistor P4. For example, when the feedback voltage Vfb1 is smaller than the reference voltage Vref2, the comparator Cp3 outputs a comparison result signal Vcr3 having a lower voltage level and raises the output of the transistor P4 so as to raise the potential of the node Nd4. For example, when the feedback voltage Vfb1 is larger than the reference voltage Vref2, the control result signal Vcr3 having a higher voltage level is output so that the output of the transistor P4 is lowered in order to lower the potential of the node Nd4.

  As described above, the dimming circuit LC1 adjusts the light emission current Ih1 output from the transistor P4 to a predetermined current value by the comparison result signal Vcr3 output from the comparison circuit CNL1, and thereby the light emitting element The light emission luminance of the group HS1 is adjusted.

  One end of the dimming circuit LC2 is connected to the node Nd1, and thereby connected to the power supply circuit VS. The other end of the dimming circuit LC2 is connected to the node Nh2. In other words, the node Nh2 is connected to the power supply circuit VS via the dimming circuit LC2 and the node Nd1. The light control circuit LC2 adjusts the light emission current Ih2 flowing through the light emitting element group HS2 to a predetermined current value, thereby adjusting the light emission luminance of the light emitting element group HS2. The dimming circuit LC2 includes a transistor P5 as a second dimming switch and a comparison circuit CNL2 as a second dimming comparison circuit.

  The comparison circuit CNL2 includes a resistance element R4, a reference power supply Ref3, and a comparator Cp4.

  One end of the resistance element R4 is connected to the power supply circuit VS, and the resistance value is, for example, 400Ω.

  One end of the reference power supply Ref3 is connected to the power supply circuit VS and one end of the resistor element R4, and supplies a reference voltage Vref3 as a second dimming reference voltage. In the illuminating device 30, the drive voltage Vk is supplied as a reference voltage Vref3 at a potential lowered by a predetermined potential.

  In the comparator Cp4, the other end of the resistor element R4 is connected to the inverting terminal, the feedback voltage Vfb2 as the second dimming comparison voltage that is the potential of the resistor element R4 is input, and the reference power source Ref3 of the reference power source Ref3 is input to the non-inverting terminal. The other end is connected and the reference voltage Vref3 is input. The comparator Cp4 compares the feedback voltage Vfb2 with the reference voltage Vref3, and outputs a comparison result signal Vcr4 as a second control signal as a comparison result from the output terminal. Here, a connection point between the other end of the resistance element R4 and the inverting terminal of the comparator Cp4 is referred to as a node Nd5. The voltage level of the feedback voltage Vfb2 is determined based on the light emission voltage Vh2.

  The transistor P5 is a PMOS transistor, and the source terminal S is connected to the node Nd5 which is the other end of the resistor element R4 and is the non-inverting terminal of the comparator Cp4. In other words, the transistor P5 is connected to the power supply circuit VS via the resistor element R4. The drain terminal D is connected to the node Nh2. The transistor P5 generates and outputs the drive voltage Vk, the light emission voltage Vh2, and the light emission current Ih2 supplied to the source terminal S from the power supply circuit VS via the resistance element R4.

  Here, the comparator Cp4 compares the feedback voltage Vfb2 and the reference voltage Vref3, and based on the comparison result, the comparison result is applied to the gate terminal G of the transistor P5 so that the potential of the node Nd5 becomes the same level as the reference voltage Vref3. The signal Vcr4 is supplied to adjust the output level of the light emission current Vh2 output from the transistor P5. For example, when the feedback voltage Vfb2 is smaller than the reference voltage Vref3, the comparator Cp4 outputs a comparison result signal Vcr4 having a lower voltage level and raises the output of the transistor P5 so as to raise the potential of the node Nd5. For example, when the feedback voltage Vfb2 is higher than the reference voltage Vref3, a control result signal Vcr4 having a higher voltage level is output so as to lower the potential of the node Nd5 and the output of the transistor P5 is controlled to be lowered.

  As described above, the dimming circuit LC2 adjusts the light emission current Ih2 output from the transistor P5 to a predetermined current value based on the comparison result signal Vcr4 output from the comparison circuit CNL2, and thereby the light emitting element The light emission luminance of the group HS2 is adjusted.

  The light control circuit LC1 and the light emitting element group HS1 connected in series with each other are connected in parallel with each other in the light control circuit LC2 and the light emitting element group HS2 connected in series with each other in the power supply circuit VS.

  The light emission control unit HCc includes a transistor P6 as a first control switch, a transistor P7 as a second control switch, and a comparison circuit CNa.

  The transistor P6 is a PMOS transistor, the source terminal S as one end is connected to the power supply circuit VS, the drain terminal D as the other end is connected to the gate terminal G of the transistor P4, and the gate terminal G as the control terminal is It is connected to the comparison circuit CNa. The transistor P6 is controlled to be turned on / off by a comparison result signal Vcr2 output from the comparison circuit CNa and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS1.

  The transistor P6 is turned on when the low-level comparison result signal Vcr2 is input to the gate terminal G from the comparison circuit CNa. As a result, the transistor P4 is short-circuited between the source terminal S and the gate terminal G and is turned off regardless of the output of the comparison result signal Vcr3. In other words, the transistor P4 cannot be turned on by the comparison result signal Vcr3. The supply of the light emission current Ih to the light emitting element group HS1 is stopped. That is, the light control circuit LC1 stops the generation of the light emission current Ih1 based on the light emission stop control of the light emission control unit HCc. The light emission stop control of the light emitting element group HS1 is performed as described above.

  The transistor P6 is turned off when the high-level comparison result signal Vcr2 is input to the gate terminal G from the comparison circuit CNa. As a result, the short-circuit between the source terminal S and the gate terminal G of the transistor P4 is released and the transistors P4 are disconnected from each other. Therefore, the current value of the light emission current Ih1 output from the transistor P4 to the light emitting element group HS1 is determined by the comparison result signal Vcr3. You will be able to control. That is, the light control circuit LC1 generates the light emission current Ih1 based on the light emission control of the light emission control unit HCc. The light emission control of the light emitting element group HS1 is performed as described above.

  Note that the first threshold voltage for turning on the transistor P6 is preferably lower than the second threshold voltage for turning on the transistor P4. The reason for this is as follows. In the transistor P6, when the drive voltage Vk is lower than the light emission reference voltage VH, the low-level comparison result signal Vcr2 is input to the gate terminal G, and the drive voltage Vk is input to the source terminal S. Then, it is turned on as the drive voltage Vk increases. On the other hand, in the transistor P4, the drive voltage Vk is input to the source terminal S, and the output of the transistor P6 is input to the gate terminal G. At this time, if the second threshold voltage of the transistor P4 is lower than the first threshold voltage of the transistor P6, the transistor P6 is turned on before the gate terminal G and the source terminal S of the transistor P4 are short-circuited. This is because the transistor P4 is turned on, and the light emitting voltage Vh1 is applied to the light emitting element group HS1, and the light emitting element group HS1 may slightly emit light.

  The transistor P7 is a PMOS transistor, the source terminal S as one end is connected to the power supply circuit VS, the drain terminal D as the other end is connected to the gate terminal G of the transistor P5, and the gate terminal G as the control terminal is It is connected to the comparison circuit CNa. The transistor P7 is turned on / off by the comparison result signal Vcr2 output from the comparison circuit CNa and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS2.

  The transistor P7 is turned on when the low-level comparison result signal Vcr2 is input to the gate terminal G from the comparison circuit CNa. As a result, the transistor P5 is short-circuited between the source terminal S and the gate terminal G and is turned off regardless of the output of the comparison result signal Vcr4. In other words, the transistor P5 cannot be turned on by the comparison result signal Vcr4. The supply of the light emission current Ih2 to the light emitting element group HS2 is stopped. That is, the light control circuit LC2 stops the generation of the light emission current Ih2 based on the light emission stop control of the light emission control unit HCc. The light emission stop control of the light emitting element group HS2 is performed as described above.

  The transistor P7 is turned off when the high-level comparison result signal Vcr2 is input to the gate terminal G from the comparison circuit CNa. As a result, the short-circuit between the source terminal S and the gate terminal G of the transistor P5 is released and the transistors P5 are disconnected from each other. Therefore, the current value of the light emission current Ih2 output from the transistor P5 to the light emitting element group HS2 is determined by the comparison result signal Vcr4. You will be able to control. That is, the light control circuit LC2 generates the light emission current Ih2 based on the light emission control of the light emission control unit HCc. The light emission control of the light emitting element group HS2 is performed as described above.

  Note that the third threshold voltage for turning on the transistor P7 is preferably lower than the fourth threshold voltage for turning on the transistor P5. The reason for this is as follows. In the transistor P7, when the drive voltage Vk is lower than the light emission reference voltage VH, the low-level comparison result signal Vcr2 is input to the gate terminal G, and the drive voltage Vk is input to the source terminal S. Then, it is turned on as the drive voltage Vk increases. On the other hand, in the transistor P5, the drive voltage Vk is input to the source terminal S, and the output of the transistor P7 is input to the gate terminal G. At this time, when the fourth threshold voltage of the transistor P5 is lower than the third threshold voltage of the transistor P7, the transistor P7 is turned on before the gate terminal G and the source terminal S of the transistor P5 are short-circuited. This is because the transistor P5 is turned on, and the light emitting voltage Vh2 is applied to the light emitting element group HS1, and the light emitting element group HS2 may slightly emit light.

  As described above, the light emission control unit HCc detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH, and when the drive voltage Vk is larger than the light emission reference voltage VH, the transistor P6 is turned off to turn on the transistor P4. Can be controlled by the comparison result signal Vcr3, the transistor P7 is turned off and the output of the transistor P5 can be controlled by the comparison result signal Vcr4, the light emission current Ih1 can be supplied to the light emitting element group HS1, and the light emission current Ih2 is Light emission control for allowing the light emitting element group HS to emit light that can be supplied to the light emitting element group HS2, that is, light emission control that enables the light control circuit LC1 to generate the light emission current Ih1, and the light control circuit LC2 to generate the light emission current Ih2. I do. When the drive voltage Vk is lower than the light emission reference voltage VH, the transistors P6 and P7 are turned on, and the outputs of the transistors P4 and P5 of the dimming circuit LC1 cannot be controlled by the comparison result signal Vcr3 and forced. By stopping, the light emission current Ih1 cannot be supplied to the light emitting element group HS1, and the light emission current Ih2 cannot be supplied to the light emitting element group HS2, and light emission stop control for stopping the light emission of the light emitting element group HS, that is, the light control circuit LC1. The light emission current Ih1 cannot be generated, and the light emission stop control is performed so that the light control circuit LC2 cannot generate the light emission current Ih2. For this reason, according to the illuminating device 30 concerning this embodiment, the light emitting element group HS1 and the light emitting element group HS2 can be light-emitted and light-extinguished simultaneously.

  FIG. 9 is a diagram illustrating the transition of each signal waveform from the rise to the fall of the power supply for driving the illumination device 30. FIG. 9A shows the transition of the drive voltage Vk over time. FIG. 9B shows the relationship between the transition of the comparison voltage Vc and the reference voltage Vref1 over time. FIG. 9C shows the transition of the comparison result signal Vcr2 over time. FIG. 9D shows transition of the light emission voltage Vh1 and the light emission voltage Vh2 over time. FIG. 9E shows the transition of the light emission current Ih1 and the light emission current Ih2 over time. 9A to 9D, the vertical axis represents voltage V and the horizontal axis represents time t. In FIG. 9E, the vertical axis represents current I, the horizontal axis represents time t, and time t20. ~ T24 is shown as a common time in FIGS. 9 (a) to 9 (e). In FIG. 9 (e), the light emission current Ih1 and the light emission current Ih2 are shown as the same current value. However, the present invention is not limited to this. In FIG. 9, the signal waveforms described in FIG. 6 according to the second embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  At time t20, driving of the power source for driving the lighting device 30 is started, and the driving voltage Vk starts to rise. At this time, since the comparison voltage Vc is 3 V or less of the reference voltage Vref1, the comparison result signal Vcr2 is at a low level. Further, since the comparison result signal Vcr2 is at a low level, when the drive voltage Vk rises and the gate-source voltage of the transistor P6 exceeds the threshold value, the transistor P6 is turned on, and the gate-source voltage of the transistor P7 becomes the threshold value. Is exceeded, the transistor P7 is turned on. As a result, the gate terminal G and the source terminal S of the transistor P4 are short-circuited to turn off the transistor P4, and the gate terminal G and the source terminal S of the transistor P5 are short-circuited to turn off the transistor P5. Therefore, the light emission voltage Vh1 is 0V and the light emission element group HS1 does not flow the light emission current Ih1, and the light emission voltage Vh2 is 0V and the light emission element group HS2 does not flow the light emission current Ih2. That is, both the light emitting element group HS1 and the light emitting element group HS2 are turned off.

  At time t21, the comparison voltage Vc becomes equal to or higher than the reference voltage Vref1, the comparison result signal Vcr2 changes to high level, and the transistors P6 and P7 are turned off. Thereby, the short circuit between the gate terminal G and the source terminal S of the transistor P4 is released, and the output of the transistor P4 can be adjusted by the comparison result signal Vcr3. As a result, the light emission luminance of the light emitting element group HS1 can be adjusted. . Here, since the light emission voltage Vh1 is about 9V, when the transistor P4 is turned on, the light emission current Ih1 flows into the light emitting element group HS1 and the light emitting element group HS1 emits light. In addition, the short circuit between the gate terminal G and the source terminal S of the transistor P5 is released, and the output of the transistor P5 can be adjusted by the comparison result signal Vcr4. As a result, the light emission luminance of the light emitting element group HS2 can be adjusted. Here, since the light emission voltage Vh2 is about 9V, when the transistor P5 is turned on, the light emission current Ih2 flows into the light emitting element group HS2 and the light emitting element group HS2 emits light. That is, all the light emitting elements HS1a in the light emitting element group HS1 and all the light emitting elements HS2a in the light emitting element group HS2 emit light without variation at the same timing.

  When driving of the power source for driving the lighting device 30 is stopped at time t22, the drive voltage Vk starts to decrease. At this time, the comparison voltage Vc, the light emission voltage Vh1, the light emission current Ih1, the light emission voltage Vh2, and the light emission current Vh2 also start to decrease.

  At time t23, the lowered drive voltage Vk becomes less than 9V and the comparison voltage Vc becomes less than 3V. As a result, the comparison result signal Vcr2 transits to a low level, the transistors P6 and P7 are turned on again, the transistors P4 and P5 are turned off, and the light emission current Ih1 that flows through the light emitting element group HS1 and the light emission that flows through the light emitting element group HS2. The current Ih2 is stopped, and the light emitting element group HS1 and the light emitting element group HS2 are turned off simultaneously. At this time, the transistor P4 and the transistor P5 are turned off when the light emission voltage Vh1 and the light emission voltage Vh2 are higher than the reference voltage VH2, which is 8V. Therefore, the light emitting element group HS1 and the light emitting element group HS2 vary at different timings. Will not turn off.

  At time t24, the drive voltage Vk decreases to 0V. Thereby, the drive of the illuminating device 30 will be in a halt condition.

  As described above, according to the illumination device 30 according to the third embodiment of the present invention, the light emission control unit HCc detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH, and the drive voltage Vk is greater than the light emission reference voltage VH. If the drive voltage Vk is lower than the light emission reference voltage VH, light emission stop control is performed to stop the light emission of the light emitting element group HS. For this reason, it is possible to prevent variations in the timing of light emission and extinction between the light emitting element group HS1 and the light emitting element group HS2.

  Further, according to the illumination device 30 according to the third embodiment of the present invention, the dimming circuit LC1 stops the generation of the light emission current Ih1 based on the light emission stop control of the light emission control unit HCc, and the light emission control unit HCc The light emission current Ih1 is generated based on the light emission control. Further, the light control circuit LC2 stops the generation of the light emission current Ih2 based on the light emission stop control of the light emission control unit HCc, and generates the light emission current Ih2 based on the light emission control of the light emission control unit HCc. For this reason, it is necessary to arrange a transistor for performing light emission control or light emission stop control in a path through which a current for causing the light emitting element group HS to emit light, as in the lighting devices 10, 10a, 10b, 20, and 20a. Therefore, an increase in the circuit area of the lighting device that can occur by using the present invention can be suppressed.

  In the lighting device 30 according to the present embodiment, the dimming circuit LC1 is connected between the power supply circuit VS and the node Nh1, and the dimming circuit LC2 is connected between the power supply circuit VS and the node Nh2. The dimming circuit LC1 is connected between the node Nh1a and the power supply VSS, and the dimming circuit LC2 is connected between the node Nh2a and the power supply VSS. May be. Even in this case, the light control circuit LC1 generates the light emission current Ih1 based on the light emission control, stops the generation of the light emission current Ih1 based on the light emission stop control, and the light control circuit LC2 emits light based on the light emission control. If the current Ih2 is generated and the generation of the light emission current Ih2 is stopped based on the light emission stop control, the effect obtained by the present embodiment, that is, an increase in circuit area can be suppressed.

  In the illumination device 30 according to the present embodiment, the example in which the other end of the reference power supply Ref3 is connected to the non-inverting terminal of the comparator Cp4 and the reference voltage Vref3 is supplied is shown. However, the present invention is not limited to this. The reference voltage Vref3 may be supplied to the non-inverting terminal of Cp4 by the reference power supply Ref2. In this case, instead of the reference power supply Ref3, the other end of the reference power supply Ref2 whose one end is connected to the power supply circuit VS and one end of the resistance element R3 is connected to the non-inverting terminal of the comparator Cp3 and the comparator Cp4. It may be configured to be connected to the non-inverting terminal. Thereby, the increase in the area of the illuminating device 30 can be suppressed.

[First Modification of Third Embodiment]
FIG. 10 is a diagram showing an illumination device 30a according to a first modification of the third embodiment of the present invention. The illumination device 30a includes a power supply circuit VS, a light emitting element group HS, a dimming circuit LC1, a dimming circuit LC2, and a light emission control unit HCc. The lighting device 30a according to the present modification is substantially different in connection destination of each of the transistor P6 and the transistor P7 in the light emission control unit HCc as compared with the lighting device 30 illustrated in FIG. In addition, in the illuminating device 30a shown in FIG. 10, the same code | symbol is attached | subjected about the structure similar to the illuminating device 30 shown in FIG. 8, and the description is abbreviate | omitted suitably.

  The drain terminal D as the other end of the transistor P6 is connected to the other end of the reference power source Ref2 and the non-inverting terminal of the comparator Cp3.

  The transistor P6 is turned on when the low-level comparison result signal Vcr1 is input to the gate terminal G from the comparison circuit CNa. Thus, the drive voltage Vk is supplied as the reference voltage Vref2 to the non-inverting terminal of the comparator Cp3 regardless of the potential supplied by the reference power supply Ref2, and the comparison result signal Vcr3 output from the comparator Cp3 is based on the feedback voltage Vfb1. The gate terminal G of the transistor P4 is set to the same level as the voltage Vref2, that is, the drive voltage Vk is not dropped by the resistance element R3, in other words, the potential at both ends of the resistance element R3 is the same. Then, the transistor P4 is controlled to be turned off, and the supply of the light emission current Ih1 to the light emitting element group HS1 is stopped. That is, the light control circuit LC1 stops the generation of the light emission current Ih1 based on the light emission stop control of the light emission control unit HCc. The light emission stop control of the light emitting element group HS1 is performed as described above.

  The transistor P6 is turned off when the high-level comparison result signal Vcr1 is input to the gate terminal G from the comparison circuit CNa. As a result, the voltage supplied from the reference power supply Ref2 is supplied as the reference voltage Vref2 to the non-inverting terminal of the comparator Cp3. Therefore, the current value of the light emission current Ih1 to the light emitting element group HS1 output from the transistor P4 is the comparison result signal. It can be controlled by Vcr3. That is, the light control circuit LC1 generates the light emission current Ih1 based on the light emission control of the light emission control unit HCc. The light emission control of the light emitting element group HS1 is performed as described above.

  The drain terminal D as the other end of the transistor P7 is connected to the other end of the reference power source Ref3 and the non-inverting terminal of the comparator Cp4.

  The transistor P7 is turned on when the low-level comparison result signal Vcr1 is input to the gate terminal G from the comparison circuit CNa. Accordingly, the drive voltage Vk is supplied as the reference voltage Vref3 to the non-inverting terminal of the comparator Cp4 regardless of the potential supplied by the reference power supply Ref3, and the comparison result signal Vcr4 output from the comparator Cp4 is based on the feedback voltage Vfb2. The gate terminal G of the transistor P5 is set at the same level as the voltage Vref3, that is, at a level such that the driving voltage Vk does not drop by the resistor element R4, in other words, the potential at both ends of the resistor element R4 is the same. The transistor P5 is controlled to be turned off, and the supply of the light emission current Ih2 to the light emitting element group HS2 is stopped. That is, the light control circuit LC2 stops the generation of the light emission current Ih2 based on the light emission stop control of the light emission control unit HCc. The light emission stop control of the light emitting element group HS2 is performed as described above.

  The transistor P7 is turned off when the high-level comparison result signal Vcr1 is input to the gate terminal G from the comparison circuit CNa. As a result, the voltage supplied from the reference power supply Ref3 is supplied as the reference voltage Vref3 to the non-inverting terminal of the comparator Cp4. Therefore, the current value of the light emission current Ih2 to the light emitting element group HS2 output from the transistor P5 is the comparison result signal. It becomes controllable by Vcr4. That is, the light control circuit LC2 generates the light emission current Ih2 based on the light emission control of the light emission control unit HCc. The light emission control of the light emitting element group HS2 is performed as described above.

  As described above, the light emission control unit HCc detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH, and when the drive voltage Vk is larger than the light emission reference voltage VH, the transistor P6 is turned off to turn on the transistor P4. Can be controlled by the comparison result signal Vcr3, the transistor P7 is turned off and the output of the transistor P5 can be controlled by the comparison result signal Vcr4, the light emission current Ih1 can be supplied to the light emitting element group HS1, and the light emission current Ih2 is Light emission control for allowing the light emitting element group HS to emit light that can be supplied to the light emitting element group HS2, that is, light emission control that enables the light control circuit LC1 to generate the light emission current Ih1, and the light control circuit LC2 to generate the light emission current Ih2. I do. When the drive voltage Vk is lower than the light emission reference voltage VH, the transistors P6 and P7 are turned on to forcibly stop the outputs of the transistors P4 and P5 of the dimming circuit LC1, thereby causing the light emission current Ih1. Cannot be supplied to the light emitting element group HS1 and the light emission current Ih2 cannot be supplied to the light emitting element group HS2 to stop the light emission of the light emitting element group HS. That is, the light control circuit LC1 cannot generate the light emission current Ih1. The light control circuit LC2 performs light emission stop control that disables generation of the light emission current Ih2. For this reason, according to the illuminating device 30 concerning this embodiment, the light emitting element group HS1 and the light emitting element group HS2 can be light-emitted and light-extinguished simultaneously.

  In the illumination device 30a according to the present embodiment, the light emission control and the light emission stop control are performed by the two transistors of the comparison circuit CNa, the transistor P6, and the transistor P7 of the light emission control unit HCc. The comparison circuit CNa and the transistor P6 may be used. In this case, instead of the transistor P7, the drain terminal D of the transistor P6 may be connected to the non-inverting terminal of the comparator Cp4 in addition to being connected to the non-inverting terminal of the comparator Cp3. .

[Second Modification of Third Embodiment]
FIG. 11 is a view showing an illumination device 30b according to a second modification of the third embodiment of the present invention. The illumination device 30b includes a power supply circuit VS, a light emitting element group HS, a light control circuit LC1, a light control circuit LC2, and a light emission control unit HCd. The illumination device 30b according to this modification is substantially different from the illumination device 30 shown in FIG. 8 in that a light emission control unit HCd is provided instead of the light emission control unit HCc. In addition, in the illuminating device 30b shown in FIG. 11, about the structure similar to the illuminating device 30 shown in FIG. 8, the same code | symbol is attached | subjected and the description is abbreviate | omitted suitably.

  The comparator Cp3 of the dimming circuit LC1 is connected to the power supply circuit VS, and is driven by receiving the drive voltage Vk output from the power supply circuit VS. That is, the comparison result signal Vcr3 is generated based on the drive voltage Vk.

  The comparator Cp4 of the dimming circuit LC2 is connected to the power supply circuit VS and driven by receiving the drive voltage Vk output from the power supply circuit VS. That is, the comparison result signal Vcr4 is generated based on the drive voltage Vk.

  The light emission control unit HCd includes a transistor N3 as a first control switch, a transistor N4 as a second control switch, and a comparison circuit CNa.

  The transistor N3 is an NMOS transistor, and has a source terminal S as one end connected to the power source VSS and a drain terminal D as the other end connected to the comparator Cp3. Thereby, the comparator Cp3 is connected to the power supply VSS via the transistor N3. The transistor N3 has a gate terminal G as a control terminal connected to the comparison circuit CNa. The transistor N3 is controlled to be turned on / off by a comparison result signal Vcr2 output from the comparison circuit CNa and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS1.

  The transistor N3 is turned off when the low-level comparison result signal Vcr2 is input to the gate terminal G from the comparison circuit CNa. As a result, the connection between the comparator Cp3 and the power source VSS is cut off, the comparison result signal Vcr3 output from the comparator Cp3 is forcibly set to the high level, and the gate terminal G of the transistor P4 has almost the same voltage as the drive voltage Vk. Level voltage is supplied. Thereby, the transistor P4 is forcibly turned off regardless of the comparison result between the reference voltage Vref2 and the feedback voltage Vfb1 in the comparator Cp3, and the supply of the light emission current Ih1 to the light emitting element group HS1 is stopped. That is, the light control circuit LC1 stops the generation of the light emission current Ih1 based on the light emission stop control of the light emission control unit HCd. The light emission stop control of the light emitting element group HS1 is performed as described above.

  The transistor N3 is turned on when the high-level comparison result signal Vcr2 is input to the gate terminal G from the comparison circuit CNa. Thereby, the comparator Cp3 and the power source VSS are electrically connected, and the comparator Cp3 can output the comparison result signal Vcr3 based on the comparison result between the reference voltage Vref2 and the feedback voltage Vfb1. Therefore, the current value of the light emission current Ih1 output from the transistor P4 to the light emitting element group HS1 can be controlled by the comparison result signal Vcr3. That is, the light control circuit LC1 generates the light emission current Ih1 based on the light emission control of the light emission control unit HCd. The light emission control of the light emitting element group HS1 is performed as described above.

  The transistor N4 is an NMOS transistor, and has a source terminal S as one end connected to the power source VSS and a drain terminal D as the other end connected to the comparator Cp4. Thereby, the comparator Cp4 is connected to the power supply VSS via the transistor N4. The transistor N4 has a gate terminal G as a control terminal connected to the comparison circuit CNa. The transistor N4 is controlled to be turned on / off by a comparison result signal Vcr2 output from the comparison circuit CNa and input to the gate terminal G, thereby performing light emission control and light emission stop control of the light emitting element group HS2.

  The transistor N4 is turned off when the low-level comparison result signal Vcr2 is input to the gate terminal G from the comparison circuit CNa. As a result, the connection between the comparator Cp4 and the power source VSS is cut off, the comparison result signal Vcr4 output from the comparator Cp4 is forcibly set to the high level, and the gate terminal G of the transistor P5 has almost the same voltage as the drive voltage Vk. Level voltage is supplied. Thereby, the transistor P5 is forcibly turned off regardless of the comparison result between the reference voltage Vref3 and the feedback voltage Vfb1 in the comparator Cp3, and the supply of the light emission current Ih2 to the light emitting element group HS2 is stopped. That is, the light control circuit LC2 stops the generation of the light emission current Ih2 based on the light emission stop control of the light emission control unit HCd. The light emission stop control of the light emitting element group HS2 is performed as described above.

  The transistor N4 is turned on when the high-level comparison result signal Vcr2 is input to the gate terminal G from the comparison circuit CNa. Thereby, the comparator Cp4 and the power source VSS are electrically connected, and the comparator Cp4 can output the comparison result signal Vcr4 based on the comparison result between the reference voltage Vref3 and the feedback voltage Vfb2. Therefore, the current value of the light emission current Ih2 output from the transistor P5 to the light emitting element group HS2 can be controlled by the comparison result signal Vcr4. That is, the light control circuit LC2 generates the light emission current Ih2 based on the light emission control of the light emission control unit HCd. The light emission control of the light emitting element group HS2 is performed as described above.

  As described above, the light emission control unit HCd detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH. When the drive voltage Vk is larger than the light emission reference voltage VH, the transistor N3 is turned on to turn on the transistor P4. Can be controlled by a comparison result signal Vcr3 based on the comparison between the reference voltage Vref2 and the feedback voltage Vfb1, and the transistor N4 is turned on, and the output of the transistor P5 is compared based on the comparison between the reference voltage Vref3 and the feedback voltage Vfb2. The light emission control that can be controlled by the signal Vcr4 so that the light emission current Ih1 can be supplied to the light emitting element group HS1 and the light emission current Ih2 can be supplied to the light emitting element group HS2 is performed. The light emission current Ih1 can be generated, and the light control circuit LC2 Controlling the light emission to be generated photocurrent Ih2. When the drive voltage Vk is smaller than the light emission reference voltage VH, the transistor N3 is turned off and controlled by the comparison result signal Vcr3 based on the comparison between the output reference voltage Vref2 of the transistor P4 of the dimming circuit LC1 and the feedback voltage Vfb1. The transistor N4 is forcibly turned off, and the transistor N4 is controlled to be uncontrollable by the comparison result signal Vcr4 based on the comparison between the output reference voltage Vref3 of the transistor P5 of the dimming circuit LC2 and the feedback voltage Vfb2. Light emission stop control for stopping the light emission of the light emitting element group HS by disabling the supply of Ih1 to the light emitting element group HS1 and the supply of the light emission current Ih2 to the light emitting element group HS2, that is, the light control circuit LC1 cannot generate the light emission current Ih1 In the dimming circuit LC2, the light emission current Ih2 is not generated. Performing emission stop control to. For this reason, according to the illuminating device 30 concerning this embodiment, the light emitting element group HS1 and the light emitting element group HS2 can be light-emitted and light-extinguished simultaneously.

  Further, in the lighting device 30b according to the present embodiment, the light emission control and the light emission stop control are performed by the two transistors of the comparison circuit CNa, the transistor N3, and the transistor N4 of the light emission control unit HCd. The comparison circuit CNa and the transistor N3 may be used. In this case, the drain terminal D of the transistor N3 may be connected to the comparator Cp4 in addition to being connected to the comparator Cp3.

[Third Modification of Third Embodiment]
FIG. 12 is a diagram showing an illumination device 30c according to a third modification of the third embodiment of the present invention. The illumination device 30c includes a power supply circuit VS, a light emitting element group HS, a light emission control unit HCe, a light control circuit LC11 as a first light control unit, and a light control circuit LC12 as a second light control unit. It is equipped with. The illumination device 30c according to the present modification includes a light emission control unit HCe instead of the light emission control unit HCc, and the dimming circuit LC1 and the dimming circuit LC2 compared to the illumination device 30 illustrated in FIG. Instead, it is substantially different in that a light control circuit LC11 and a light control circuit LC12 are provided. In addition, in the illuminating device 30c shown in FIG. 12, about the structure similar to the illuminating device 30 shown in FIG. 8, the same code | symbol is attached | subjected and the description is abbreviate | omitted suitably.

  The light emission control unit HCe detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH, and performs light emission control for causing the light emitting element group HS to emit light when the drive voltage Vk is greater than the light emission reference voltage VH. When the voltage Vk is lower than the light emission reference voltage VH, light emission stop control is performed to stop the light emission of the light emitting element group HS. The light emission control unit HCe includes a comparison circuit CN.

  One end of the dimming circuit LC11 is connected to the node Nd1, and thereby connected to the power supply circuit VS. The other end of the dimming circuit LC11 is connected to the node Nh1. In other words, the node Nh1 is connected to the power supply circuit VS via the dimming circuit LC11 and the node Nd1. The light control circuit LC11 adjusts the light emission current Ih1 flowing through the light emitting element group HS1 to a predetermined current value, and thereby adjusts the light emission luminance of the light emitting element group HS1. The dimming circuit LC11 includes a transistor PD1 as a first dimming switch, a current generation circuit VC1 as a first current generation circuit, a comparison circuit CNL11 as a first dimming comparison circuit, and a first drive. And a drive circuit KD1 as a circuit.

  The transistor PD1 is a PMOS transistor, and the source terminal S is connected to the power supply circuit VS.

  The current generation circuit VC1 includes an inductor L1, a capacitor C1, and a rectifier diode D1. One end of the inductor L1 is connected to the drain terminal D of the transistor PD1. One end of the capacitor C1 is connected to the other end of the inductor L1, and the other end is connected to the power source VSS. The rectifier diode D1 has an anode connected to the power supply VSS and a cathode connected to a connection point between the drain terminal D of the transistor PD1 and one end of the inductor L1.

  The current generation circuit VC1 accumulates magnetic energy based on the drive voltage Vk output from the transistor PD1 when the transistor PD1 is turned on by the inductor L1, and smoothes it by the capacitor C1 to generate the light emission voltage Vh1 and the light emission current Ih1. And output. Further, when the transistor PD1 is off, the current generation circuit VC1 supplies the magnetic energy accumulated in the inductor L1 to the capacitor C1 via the rectifier diode D1, and the magnetic energy is smoothed by the capacitor C1 to emit light. A voltage Vh1 and a light emission current Ih1 are generated and output. That is, the current generation circuit VC1 steps down the drive voltage Vk obtained according to the on / off state of the transistor PD1 to generate and output the light emission voltage Vh1 and the light emission current Ih1.

  The comparison circuit CNL11 has a reference power supply Ref4 and a comparator Cp5.

  One end of the reference power supply Ref4 is connected to the power supply VSS, and generates a reference voltage Vref4 as a first dimming reference voltage. The reference voltage Vref4 is 2V, for example.

  In the comparator Cp5, the node Nd8 at the connection point between the node Nh1a and the resistance element Rh1 is connected to the non-inverting terminal, and the feedback voltage Vfb3 as the first dimming comparison voltage that is the potential of the node Nd8 is input. A reference power supply Ref4 is connected and a reference voltage Vref4 is input. The comparator Cp5 compares the feedback voltage Vfb3 with the reference voltage Vref4 and, based on the comparison result, the comparison result signal as the first control signal so that the potential of the node Nd8 becomes the same level as the reference voltage Vref4. Vcr5 is output to adjust the magnitude of the light emission current Vh1 generated by the transistor PD1 and the current generation circuit VC1. For example, when the feedback voltage Vfb3 is smaller than the reference voltage Vref4, the comparator Cp5 outputs a high-level comparison result signal Vcr5 to increase the potential of the node Nd8. For example, when the feedback voltage Vfb3 is higher than the reference voltage Vref4, the comparator Cp5 outputs a low-level comparison result signal Vcr5 so as to lower the potential of the node Nd8.

  As described above, the comparison circuit CNL11 detects the feedback voltage Vfb3 based on the light emission voltage Vh1, and outputs the comparison result signal Vcr5 so that the light emission current Ih1 flowing through the light emitting element group HS1 becomes a desired value. Adjust the output of PD1.

  The drive circuit KD1 is connected to the gate terminal G as the control terminal of the transistor PD1 and the output terminal of the comparator Cp5 of the comparison circuit CNL11. The drive circuit KD1 receives the comparison result signal Vcr5 output from the comparator Cp5, in other words, the comparison circuit CNL11. In response, the drive signal Vs1 as the first drive signal is supplied to the transistor PD1. For example, when the low-level comparison result signal Vcr5 is received, the drive circuit KD1 supplies the high-level drive signal Vs1 to, for example, 5V to the gate terminal G of the transistor PD1. Thereby, the transistor PD1 is turned off, and the supply of the voltage based on the drive voltage Vk to the inductor L1 is stopped. For example, when the high-level comparison result signal Vcr5 is received, the low-level drive signal Vs1 of, for example, 0V is supplied to the gate terminal G of the transistor PD1. As a result, the transistor PD1 is turned on, and a voltage based on the drive voltage Vk is supplied to the inductor L1. The drive circuit KD1 may be configured to perform PWM control for supplying a PWM signal having a predetermined duty ratio to the gate terminal G of the transistor PD1.

  As described above, the dimming circuit LC11 adjusts the light emission current Ih1 output from the transistor PD1 to a predetermined current value by the drive signal Vs1 based on the comparison result signal Vcr5 output from the comparison circuit CNL11. Thus, the light emission luminance of the light emitting element group HS1 is adjusted.

  One end of the dimming circuit LC12 is connected to the node Nd1, and thereby connected to the power supply circuit VS. The other end of the dimming circuit LC12 is connected to the node Nh2. In other words, the node Nh2 is connected to the power supply circuit VS via the dimming circuit LC12 and the node Nd1. The light control circuit LC12 adjusts the light emission current Ih2 flowing through the light emitting element group HS2 to a predetermined current value, thereby adjusting the light emission luminance of the light emitting element group HS2. The dimming circuit LC12 includes a transistor PD2 as a second dimming switch, a current generation circuit VC2 as a second current generation circuit, a comparison circuit CNL12 as a second dimming comparison circuit, and a second drive. And a drive circuit KD2 as a circuit.

  The transistor PD2 is a PMOS transistor, and the source terminal S is connected to the power supply circuit VS.

  The current generation circuit VC2 includes an inductor L2, a capacitor C2, and a rectifier diode D2. One end of the inductor L2 is connected to the drain terminal D of the transistor PD2. One end of the capacitor C2 is connected to the other end of the inductor L2, and the other end is connected to the power source VSS. The rectifier diode D2 has an anode connected to the power supply VSS and a cathode connected to a connection point between the drain terminal D of the transistor PD2 and one end of the inductor L2.

  The current generation circuit VC2 accumulates magnetic energy based on the drive voltage Vk output from the transistor PD2 when the transistor PD2 is turned on by the inductor L2, and smoothes it by the capacitor C2 to generate the light emission voltage Vh2 and the light emission current Ih2. And output. In addition, when the transistor PD2 is off, the current generation circuit VC2 supplies the magnetic energy accumulated in the inductor L2 to the capacitor D2 via the rectifier diode D2, and the magnetic energy is smoothed by the capacitor C2 to emit light. A voltage Vh2 and a light emission current Ih2 are generated and output. That is, the current generation circuit VC2 steps down the drive voltage Vk obtained according to the on / off state of the transistor PD2 to generate and output the light emission voltage Vh2 and the light emission current Ih2.

  The comparison circuit CNL12 has a reference power supply Ref5 and a comparator Cp6.

  One end of the reference power supply Ref5 is connected to the power supply VSS, and generates a reference voltage Vref5 as a second dimming reference voltage. The reference voltage Vref5 is 2V, for example.

  In the comparator Cp6, the node Nd9 at the connection point between the node Nh2a and the resistance element Rh2 is connected to the non-inverting terminal, and the feedback voltage Vfb4 as the second dimming comparison voltage that is the potential of the node Nd9 is input. A reference power supply Ref5 is connected and a reference voltage Vref5 is input. The comparator Cp6 compares the feedback voltage Vfb4 and the reference voltage Vref5, and based on the comparison result, the comparison result signal as the second control signal is set so that the potential of the node Nd9 becomes the same level as the reference voltage Vref5. Vcr6 is output to adjust the magnitude of the light emission current Vh2 generated by the transistor PD2 and the current generation circuit VC2. For example, when the feedback voltage Vfb4 is smaller than the reference voltage Vref5, the comparator Cp6 outputs a high-level comparison result signal Vcr6 to increase the potential of the node Nd9. For example, when the feedback voltage Vfb4 is higher than the reference voltage Vref5, the comparator Cp6 outputs a low-level comparison result signal Vcr6 so as to lower the potential of the node Nd9.

  As described above, the comparison circuit CNL12 detects the feedback voltage Vfb4 based on the light emission voltage Vh2, and outputs the comparison result signal Vcr6 so that the light emission current Ih2 flowing in the light emitting element group HS2 becomes a desired value. Adjust the output of PD2.

  The drive circuit KD2 is connected to the gate terminal G as a control terminal of the transistor PD2 and the output terminal of the comparator Cp6 of the comparison circuit CNL12. The drive circuit KD2 receives the comparison result signal Vcr6 output from the comparator Cp6, in other words, the comparison circuit CNL12. In response, a drive signal Vs2 as a second drive signal is supplied to the transistor PD2. For example, when the low-level comparison result signal Vcr6 is received, the drive circuit KD2 supplies the high-level drive signal Vs2 to, for example, 5V to the gate terminal G of the transistor PD2. As a result, the transistor PD2 is turned off, and the supply of the voltage based on the drive voltage Vk to the inductor L2 is stopped. For example, when the high-level comparison result signal Vcr6 is received, the low-level driving signal Vs2 at 0V, for example, is supplied to the gate terminal G of the transistor PD2. As a result, the transistor PD2 is turned on, and a voltage based on the drive voltage Vk is supplied to the inductor L2. The drive circuit KD2 may be configured to perform PWM control for supplying a PWM signal having a predetermined duty ratio to the gate terminal G of the transistor PD2.

  As described above, the dimming circuit LC12 adjusts the light emission current Ih2 output from the transistor PD2 to a predetermined current value with the drive signal Vs2 based on the comparison result signal Vcr6 output from the comparison circuit CNL12. Thus, the light emission luminance of the light emitting element group HS2 is adjusted.

  When the drive voltage Vk is lower than the light emission reference voltage VH and the light emission control unit HCe needs to perform light emission stop control, the drive circuit KD1 is supplied with the low-level comparison result signal Vcr1 and is output to the output of the comparison circuit CNL11. Regardless, the high-level drive signal Vs1 is output to forcibly turn off the transistor PD1. Thereby, the supply of the light emission current Ih1 to the light emitting element group HS1 is stopped. Further, when the drive voltage Vk is higher than the light emission reference voltage VH and the light emission control unit HCe needs to perform light emission control, the drive circuit KD1 is supplied with the high-level comparison result signal Vcr1 and the output of the comparison circuit CNL11. A drive signal Vs1 corresponding to the above is output to control on / off of the transistor PD1. As a result, the current value of the light emission current Ih1 flowing through the light emitting element group HS1 can be controlled by the comparison result signal Vcr5.

  When the drive voltage Vk is lower than the light emission reference voltage VH and the light emission control unit HCe needs to perform light emission stop control, the drive circuit KD2 is supplied with the low-level comparison result signal Vcr1 and is output to the output of the comparison circuit CNL12. Regardless, the high level drive signal Vs2 is output to forcibly turn off the transistor PD2. Thereby, the supply of the light emission current Ih2 to the light emitting element group HS2 is stopped. Further, when the drive voltage Vk is higher than the light emission reference voltage VH and the light emission control unit HCe needs to perform light emission control, the drive circuit KD2 is supplied with the high-level comparison result signal Vcr2, and the output of the comparison circuit CNL12 A drive signal Vs2 corresponding to the output is output to control on / off of the transistor PD2. Thus, the current value of the light emission current Ih2 flowing through the light emitting element group HS2 can be controlled by the comparison result signal Vcr6.

  As described above, according to the illumination device 30c according to the third modified example of the third embodiment of the present invention, the light emission control unit HCe detects the magnitude relationship between the drive voltage Vk and the light emission reference voltage VH, and the drive voltage Vk. Is controlled to emit light when the driving voltage Vk is lower than the light emission reference voltage VH, light emission stop control is performed to stop the light emission of the light emitting element group HS. Do. For this reason, it is possible to prevent variations in the timing of light emission and extinction between the light emitting element group HS1 and the light emitting element group HS2.

  In addition, although the asynchronous rectification step-down converter using the rectifier diodes D1 and D2 has been described as an example of the lighting device 30c, the lighting device 30c is not limited thereto, and may be a synchronous rectification step-down converter. Further, the present invention is not limited to the step-down converter, and may be a step-up converter or a step-up / step-down converter.

  In the illumination device 30c, PMOS transistors are employed as the transistors PD1 and PD2, but NMOS transistors may be employed as these transistors. In this case, when receiving the low-level comparison result signal Vcr5, the drive circuit KD1 supplies the low-level drive signal Vs1 to, for example, 0V to the gate terminal G of the transistor PD1, and the high-level comparison result signal When Vcr5 is received, for example, a high-level drive signal Vs1 at 5V may be supplied to the gate terminal G of the transistor PD1. In addition, when receiving the low level comparison result signal Vcr6, the drive circuit KD2 supplies the low level drive signal Vs2 to the gate terminal G of the transistor PD2, for example, at 0V, and receives the high level comparison result signal Vcr6. In this case, for example, a high level drive signal Vs2 at 5V may be supplied to the gate terminal G of the transistor PD2. When an NMOS transistor is used as the transistor PD1, the drive circuit KD1 may boost the comparison result signal Vc5 to generate the drive signal Vs1, and when an NMOS transistor is used as the transistor PD2, The drive circuit KD2 may boost the comparison result signal Vc6 to generate the drive signal Vs2.

  Since the illumination device according to the present invention can prevent variations in the light emission timing of the light emitting elements of each light emitting element group, the industrial applicability is extremely high.

VS power supply circuit HC, HCa, HCb, HCc, HCd, HCe Light emission control unit CN, CNa, CNL1, CNL2, CNL1a, CNL2a Comparison circuit LC1, LC2, LC1a, LC2a Dimming circuit Vk driving voltage Ik driving current Vh1, Vh2 Light emitting voltage Ih1, Ih2 Light emitting current HS, HS1, HS2 Light emitting element group HS1a, HS2a Light emitting element Vc Comparative voltage Vref1, Vref2, Vref3 Reference voltage Ref1, Ref2, Ref3, Ref4, Ref5 Reference power supply Vcr1, rcr4c, Vcr3c , Vcr6 Comparison result voltage Cp1, Cp2, Cp3, Cp4, Cp5, Cp6 Comparator Rh1, Rh2, Rh3, Rh4, R1, R2, R3, R4 Resistance element N1, N2, N3, N4, N5, N6, P1, P , P3, P4, P5, P6, P7 transistor

Claims (14)

A power supply circuit for supplying a driving voltage;
A plurality of first light-emitting elements connected in series that emit light when a first light-emitting voltage based on the driving voltage is applied at a level equal to or higher than a first light-emitting reference voltage; When the second light emission voltage based on the first light emitting element group and the driving voltage is applied at a second light emission reference voltage higher than the first light emission reference voltage, the second light emission current flows. A second light emitting element group including a plurality of second light emitting elements connected in series with each other, and a light emission voltage equal to or higher than a light emission reference voltage based on the second light emission reference voltage is applied A light emitting element group that emits light in a case;
A magnitude relationship between the drive voltage and the light emission reference voltage is detected, and when the drive voltage is larger than the light emission reference voltage, light emission control for causing the light emitting element group to emit light is performed, and the drive voltage is the light emission reference voltage. A light emission control unit for performing light emission stop control for stopping light emission of the light emitting element group when smaller than,
A lighting device comprising: The light emission control by the light emission controller enables the first light emission current to be supplied to the first light emitting element group and the second light emission current to be supplied to the second light emitting element group. To do
The light emission stop control by the light emission control unit is such that the first light emitting current cannot be supplied to the first light emitting element group and the second light emitting current cannot be supplied to the second light emitting element group. The lighting device according to claim 1, wherein the lighting device is performed. A first dimming unit for adjusting a current value of the first light emission current;
A second light control unit for adjusting a current value of the second light emission current;
The lighting device according to claim 2, wherein: The light emission control unit
A first comparison circuit that compares the comparison voltage based on the drive voltage with a first reference voltage and outputs a comparison result signal;
A first control switch in which the comparison result signal is supplied to a control terminal and on / off is controlled;
With
The lighting device according to claim 3, wherein the light emission control and the light emission stop control are performed based on an on / off control of the first control switch.   The first control switch is connected to the power supply circuit, the first dimming unit, and the second dimming unit, and the driving voltage when the first control switch is turned on. Is supplied to the first dimming unit and the driving voltage is supplied to the second dimming unit. When the first control switch is turned off, the driving voltage is supplied to the first dimming unit. The lighting device according to claim 4, wherein the lighting device is stopped from being supplied to the second light source and is stopped from being supplied to the second light control unit. A second control switch for performing the light emission control and the light emission stop control by supplying the comparison result signal to a control terminal and controlling on / off;
The first control switch is connected to the first dimming unit and the first light emitting element group. When the first control switch is turned on, the first light emitting current is Supplying to the first light emitting element group, and stopping supplying the first light emitting current to the first light emitting element group when the first control switch is turned off;
The second control switch is connected to the second dimming unit and the first light emitting element group, and when the second control switch is turned on, the second light emitting current is The second light-emitting element group is supplied, and when the second control switch is turned off, the supply of the second light-emitting current to the second light-emitting element group is stopped. Item 5. The lighting device according to Item 4. A second control switch for performing the light emission control and the light emission stop control by supplying the comparison result signal to a control terminal and controlling on / off;
The first control switch is an NMOS transistor connected to the first light emitting element group and a first power supply having a voltage level lower than the drive voltage, and the first control switch is turned off. When the first control switch is turned on, the first light-emitting current is allowed to flow to the first light-emitting element group. ,
The second control switch is an NMOS transistor connected to the second light emitting element group and the first power source. When the second control switch is turned off, the second control current is reduced. 5. The flow of the second light emitting element group is stopped, and the second light emitting current is caused to flow to the second light emitting element group when the second control switch is turned on. The lighting device described in 1. The first dimming unit generates the first light emission current based on the light emission control, stops the generation of the first light emission current based on the light emission stop control,
The said 2nd light control part produces | generates the said 2nd light emission current based on the said light emission control, and stops the production | generation of the said 2nd light emission current based on the said light emission stop control. 3. The lighting device according to 3. The first dimming unit includes:
Based on the comparison between the first dimming comparison voltage based on the first light emission voltage and the first dimming reference voltage, the first light emission voltage becomes the same level as the first dimming reference voltage. A first dimming comparison circuit that outputs a first control signal to
A first dimming switch connected to the power supply circuit and the first light emitting element group, wherein a signal based on the first control signal is input to a control terminal and an output level is controlled;
With
In the light emission control, an output level of the first dimming switch is controlled by the first control signal, the first light emission current is generated and supplied to the first light emitting element group, and the light emission In the stop control, the first dimming switch is turned off to stop the generation of the first light emission current,
The second dimming unit is
Based on the comparison between the second dimming comparison voltage based on the second light emission voltage and the second dimming reference voltage, the second light emission voltage becomes the same level as the second dimming reference voltage. A second dimming comparison circuit that outputs a second control signal to
A second dimming switch connected to the power supply circuit and the second light emitting element group, wherein a signal based on the second control signal is input to a control terminal and an output level is controlled;
With
In the light emission control, an output level of the second dimming switch is controlled by the second control signal, the second light emission current is generated and supplied to the second light emitting element group, and the light emission The lighting device according to claim 8, wherein in the stop control, the second dimming switch is turned off to stop the generation of the second light emission current. The light emission control unit
A first comparison circuit that compares the comparison voltage based on the drive voltage with a first reference voltage and outputs a comparison result signal;
A first control switch in which the comparison result signal is supplied to a control terminal and on / off is controlled;
A second control switch in which the comparison result signal is supplied to a control terminal and on / off is controlled;
With
In the light emission control, the first dimming switch can be controlled by the first control signal based on on / off of the first control switch, and the second control switch can be controlled based on on / off of the second control switch. The dimming switch is made controllable by the second control signal,
The light emission stop control makes it impossible to control the first dimming switch by the first control signal based on on / off of the first control switch, and based on on / off of the second control switch. The lighting device according to claim 9, wherein the lighting device is configured by disabling the second dimming switch from being controlled by the second control signal. The first dimming switch in the first dimming unit is a PMOS transistor having a source terminal connected to the power supply circuit and a drain terminal connected to the first light emitting element group,
The second dimming switch in the second dimming unit is a PMOS transistor having a source terminal connected to the power supply circuit and a drain terminal connected to the second light emitting element group,
The first control switch has one end connected to the source terminal of the first dimming switch and the other end connected to the gate terminal of the first dimming switch.
The second control switch has one end connected to the source terminal of the second dimming switch and the other end connected to the gate terminal of the second dimming switch.
In the light emission control, the first control switch is turned off and the source terminal and the gate terminal of the first dimming switch are disconnected from each other, and the second control switch is turned off and the second control switch is turned off. The source terminal and gate terminal of the dimmer switch are disconnected from each other.
In the light emission stop control, the first control switch is turned on, the source terminal and the gate terminal of the first dimming switch are short-circuited, and the first dimming switch is turned off; The second control switch is turned on, the source terminal and the gate terminal of the second dimming switch are short-circuited, and the second dimming switch is turned off. Lighting device. The first control switch has one end connected to the power supply circuit and the other end connected to the first dimming comparison circuit,
The second control switch has one end connected to the power supply circuit and the other end connected to the second dimming comparison circuit,
In the light emission stop control, the first control switch is turned on, the drive voltage is supplied as the first dimming reference voltage to the first dimming comparison circuit, and the first dimming switch is turned on. The second dimming switch is controlled so as to be turned off, and the second control switch is turned on and the drive voltage is supplied to the second dimming comparison circuit as the second dimming reference voltage. Is controlled to be turned off,
In the light emission control, the first control switch is turned off and the first dimming switch is controlled by the first control signal, and the second control switch is turned off and the second dimming control is performed. The lighting device according to claim 10, wherein a switch is controlled by the second control signal. The first dimming unit turns off the first dimming switch by fixing the level of the first control signal output from the first dimming comparison circuit based on the light emission stop control. ,
The second dimming unit turns off the second dimming switch by fixing the level of the second control signal output from the second dimming comparison circuit based on the light emission stop control. The lighting device according to claim 9. The first dimming unit includes:
A voltage based on the drive voltage obtained when the first dimming switch is turned on is accumulated in an inductor and smoothed by a capacitor to generate the first light emission voltage and the first light emission current. A first current generation circuit for outputting to the first light emitting element group;
A first drive circuit for controlling an output level of the first dimming switch based on the first control signal output from the first dimming comparison circuit;
With
In the light emission control, the light emission control unit validates the control of the first dimming switch of the first drive circuit, and the output level of the first dimming switch according to the first control signal is set. Control becomes possible,
In the light emission stop control, the light emission control unit invalidates the control of the first drive circuit with respect to the first dimming switch, and the output level of the first dimming switch according to the first control signal. Control is stopped,
The second dimming unit is
A voltage based on the drive voltage obtained when the second dimming switch is turned on is accumulated in an inductor and smoothed by a capacitor to generate the second light emission voltage and the second light emission current. A second current generation circuit for outputting to the second light emitting element group;
A second drive circuit for controlling an output level of the second dimming switch based on the second control signal output from the second dimming comparison circuit;
With
In the light emission control, the light emission control section enables the control of the first dimming switch of the second drive circuit, and the output level of the second dimming switch according to the second control signal is set. Control becomes possible,
In the light emission stop control, the light emission control unit disables the control of the second drive circuit with respect to the second dimming switch, and the output level of the second dimming switch according to the second control signal. The lighting device according to claim 9, wherein the control of is stopped.

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