JP2020155376A - Control circuit for lighting device - Google Patents

Abstract

To provide a control circuit for a lighting device capable of handling a wide range of power supply voltages and intentionally dimming.SOLUTION: The control circuit for a lighting device includes: a comparator for comparing a reference voltage with a voltage applied through a negative voltage input unit and absorbing an electric current of an amount according to a comparison result; and a dimming signal input unit S +, connected to the negative voltage input unit of the comparator and for accepting a dimming signal input from outside. There is included a dimming signal control unit for performing dimming control by the dimming signal.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control circuit capable of supporting a wide range of power supply voltages in a lighting device specialized in a system for supplying direct current, which uses a direct current voltage as a power source.

With the recent evolution of LED (light emitting diode) technology, various LED lighting devices are used. Therefore, the LED lighting device is required to be miniaturized, highly efficient, and inexpensive.

Among them, the power supply source of LED lighting devices that use DC voltage as the power source is not limited to one, and due to the growing awareness of energy saving in recent years, there are various power sources such as photovoltaic power generation, which is renewable energy, and various battery power. Over.

The difference in DC voltage output from these power supplies was dealt with by using a power conversion unit. However, the configuration using the power conversion unit has a problem that a loss due to conversion occurs and the efficiency is lowered.

In addition, most of the power conversion units are configured to keep the output constant by switching at a specific frequency. Such a power conversion unit has a big demerit that electromagnetic noise is generated by the switching operation.

On the other hand, in a configuration that does not use a power conversion unit, it is possible to keep the current flowing through the LED constant for a DC voltage in a certain range, but for slight fluctuations in the DC voltage outside that range. , The current flowing through the LED changes significantly. Therefore, the quality of the light output from the LED lighting is deteriorated, the life of the LED is shortened, or the LED is burnt out.

Further, when the DC voltage drops below a predetermined value, the order (direction) voltage required to turn on the LED becomes insufficient, and the LED turns off. Therefore, there is a problem that it cannot correspond to a wide range of power supply voltages.

Therefore, there is a demand for a control circuit for an LED lighting device that can handle a wide range of power supply voltages without using a power supply conversion unit. Patent Document 1 discloses a configuration in which the current flowing through the LED is kept constant while supporting a wide range of power supply voltages by controlling the lighting and extinguishing of the LED according to the increase and decrease of the power supply voltage. Further, Patent Document 2 discloses a configuration in which the lighting device as a whole does not cause a difference in brightness while supporting a wide range of power supply voltages by controlling the lighting and extinguishing of LEDs according to the increase and decrease of the power supply voltage. .. Further, Patent Document 3 discloses a configuration in which the current flowing through the LED is kept constant while supporting a wide range of power supply voltages by converting the series-parallel connection of the LEDs according to the increase or decrease of the power supply voltage.

Japanese Unexamined Patent Publication No. 2013-179279 Japanese Patent No. 6441613 JP-A-2018-106929

However, in the configurations of Patent Documents 1 to 3, the illuminance of the LED automatically fluctuates according to the increase or decrease of the power supply voltage.

Therefore, an object of the present invention is to provide a control circuit for a lighting device capable of dealing with a wide range of power supply voltages and intentionally dimmable as a solution to the above-mentioned problems. is there.

The invention of claim 1 is
A comparator that compares the reference voltage with the voltage applied through the negative voltage input section and sucks in an amount of current according to the comparison result.
It is provided with a dimming signal input section that is connected to the negative voltage input section of the comparator and receives dimming signal input from the outside.
It is a control circuit for a lighting device having a dimming signal control unit that controls dimming by the dimming signal.

Further, the invention of claim 2 is
The control circuit for the lighting device according to claim 1, wherein the comparator is a comparator.

Further, the invention of claim 3 is
A DC power supply that applies a DC voltage and
An LED constantly lit unit equipped with an LED that constantly lights when a voltage is applied from the DC power supply,
An LED series-parallel converter with LEDs that the series-parallel connection converts,
The lighting device according to claim 1 or 2, further comprising an LED series-parallel control unit that converts the series-parallel connection of LEDs according to the LED series-parallel conversion unit according to the amount of current sucked into the comparator. It was used as a control circuit for.

Further, the invention of claim 4 is
A DC power supply that applies a DC voltage and
An LED constantly lit unit equipped with an LED that constantly lights when a voltage is applied from the DC power supply,
An LED lighting / extinguishing unit equipped with an LED that turns on or off,
The control circuit for a lighting device according to claim 1 or 2, further comprising an LED lighting / extinguishing control unit that controls an LED related to the LED lighting / extinguishing unit according to the amount of current sucked into the comparator. And said.

According to the inventions of claims 1 to 4, it is possible to deal with a wide range of power supply voltages without using a power supply conversion unit, and dimming can be intentionally performed by receiving an input of a dimming signal from the outside.

In addition, since the configuration does not use a power conversion unit, it is possible to reduce the size, efficiency, and price of the lighting device. In addition, it does not generate electromagnetic noise and can be used in environments such as hospitals and precision machine rooms where electromagnetic noise is disliked. Furthermore, the risk of failure of the lighting device can be reduced.

It is a conceptual block diagram of Embodiment 1 of this invention. It is a block diagram of Embodiment 1 of this invention. It is a graph which showed the experimental result of the dimming characteristic which concerns on Embodiment 1 of this invention. It is a block diagram of Embodiment 1 of this invention. It is a block diagram of Embodiment 1 of this invention. It is a block diagram of Embodiment 1 of this invention. It is a block diagram of the other Embodiment example of this invention. It is a block diagram of the other Embodiment example of this invention. It is a block diagram of the other Embodiment example of this invention. It is a block diagram of the other Embodiment example of this invention. It is a conceptual block diagram of Embodiment 2 of this invention. It is a block diagram of Embodiment 2 of this invention. It is a conceptual block diagram of Embodiment 3 of this invention. It is a block diagram of Embodiment 3 of this invention. It is a block diagram of the other Embodiment example of this invention.

(Example 1 of the embodiment)
First, it will be described with reference to FIG. 1, which is a conceptual configuration diagram of the first embodiment of the present invention. The control circuit for the lighting device of the present invention is provided with the LED constantly lighting unit 51 in which the LED is constantly lit by applying the voltage of the DC power supply 50, and the LEDs are connected in series and parallel by the fluctuation of the voltage value of the DC power supply 50. An LED series-parallel conversion unit 52 to be converted is provided, and an LED series-parallel control unit 53 that automatically converts the LED series-parallel connection related to the LED series-parallel conversion unit 52 according to a fluctuation in the voltage value is provided. A dimming signal control unit 54 that receives an input of a dimming signal from the outside and performs dimming control by the dimming signal is provided, and further, a voltage drop is performed for an excessive voltage component exceeding a predetermined voltage value. The overvoltage absorbing unit 55 is provided. Further, each part is connected through a current path 56.

In the control circuit for this lighting device, the LEDs related to the LED constant lighting unit 51 and the LED series-parallel conversion unit 52 are lit by the DC voltage applied from the DC power supply 50, but the DC voltage is caused by fluctuations in the DC power supply 50 or the like. When the voltage fluctuates, the LED series-parallel control unit 53 operates, and the series-parallel connection of the LED series-parallel conversion unit 52 is converted. Therefore, in the lighting device provided with this control circuit, all the LEDs related to the LED constant lighting unit 51 and the LED series-parallel conversion unit 52 are in the lighting state, and it is difficult for the surrounding people to notice the fluctuation of the power supply voltage.

Next, the configuration of the control circuit A for the lighting device according to the first embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 2, the current path 2 and the current path 3 are connected to the positive electrode of the DC power supply 1, respectively.

In the current path 2, semiconductor light emitting elements LEDs 1 to 3 made of LEDs are connected in series in the same polar direction, and the current path 21 and the current path are provided from the cathode side of the semiconductor light emitting element LED 3 in the lower voltage direction. It branches into two of 22.

In the current path 21, semiconductor light emitting elements LEDs 4 to 6 composed of LEDs are connected in series in the same polar direction, and the cathode of the semiconductor light emitting element LED 6 and the drain of the semiconductor control element FET (field effect transistor) 2 are provided. They are connected in series. Further, in the current path 22, the source of the semiconductor control element FET1 is connected in series in the same polar direction, and among the semiconductor light emitting elements LEDs 7 to 9 made of LEDs, the source is connected in series with the anode of the semiconductor light emitting element LED7. It is connected.

Further, a diode connects the current path 21 between the cathode of the semiconductor light emitting element LED6 and the drain of the semiconductor control element FET2 and the current path 22 between the source of the semiconductor control element FET1 and the anode of the semiconductor control element LED7. The semiconductor rectifying element D1 is provided. Specifically, the anode of the semiconductor rectifying element D1 is connected to the current path 21 between the cathode of the semiconductor light emitting element LED6 and the drain of the semiconductor control element FET2, and the cathode of the semiconductor rectifying element D1 is the source of the semiconductor control element FET1 and semiconductor light emitting. It is connected to the current path 22 between the anodes of the element LED 7. Taking advantage of the characteristic that the current flows only in the forward direction, the semiconductor rectifying element D1 prevents a current from flowing from the source of the semiconductor control element FET1 to the drain of the semiconductor control element FET2 when the semiconductor control element FET1 is turned on. , Plays a role in cutting off the current. By providing the semiconductor rectifying element D1 in this way, when the semiconductor control element FET1 and the semiconductor control element FET2 are turned on, a current flows in the current path 21 and the current path 22 substantially equally.

The source of the semiconductor control element FET 2 and the cathode of the semiconductor light emitting element LED 9 are connected, and the current path 2 that has branched into two, the current path 21 and the current path 22, returns to one current path 2 here, and from this The semiconductor control element FET3, the semiconductor light emitting element LED10, and the resistance element R3 are provided in series in order from the lower voltage downward direction. The resistance element R3 is a shunt resistance, and the current flowing through the control circuit A for the lighting device based on the voltage (drop) between the terminals of the resistance element R3 and the resistance value of the resistance element R3 in the detection circuit (not shown). Detect the value.

Further, when an excessive voltage exceeding a predetermined voltage value is applied from the DC power supply 1, the semiconductor control element FET 3 plays a role of lowering the voltage for the excessive voltage. For example, when the withstand voltage of the semiconductor control element FET3 is 500V and the predetermined voltage of the control circuit A for the lighting device is 29.3V, when an excessive voltage of 32V is applied, the semiconductor control element FET3 has an excessive voltage. It absorbs (= takes charge of) 2.7V, which is a minute, between the drain and the source, lowers the voltage, and keeps the amount of current flowing in the control circuit A for the lighting device in a predetermined state.

On the other hand, in the current path 3, the resistance element R4, the semiconductor control element TR (transistor), and the resistance element R5 are connected in series in order from the lower voltage direction. Then, one end of the resistance element 5 on the lower voltage side is connected to the output of the comparator.

Further, the resistance element R3 of the current path 2 and the negative power supply terminal V- of the comparator are connected to the negative electrode (≈GND) of the DC power supply 1, respectively.

The gate of the semiconductor control element FET1 is connected to the collector of the semiconductor control element TR via the resistance element R1, and the gate of the semiconductor control element FET2 is connected to the collector of the semiconductor control element TR via the resistance element R2. There is. Further, a semiconductor constant voltage element ZD1 is provided between the source and the gate of the semiconductor control element FET1, and a semiconductor constant voltage element ZD2 is provided between the source and the gate of the semiconductor control element FET2. These semiconductor constant voltage elements ZD1 and ZD2 are composed of Zener diodes, and take advantage of the characteristics of Zener diodes that the voltage becomes constant with respect to changes in current to limit the voltage applied between the source and the gate. Therefore, it plays a role of protecting the semiconductor control elements FET1 and FET2 when a surge current or static electricity is generated.

Further, the connection point of the resistance element R2 on the current path 3 and the collector of the semiconductor control element TR and the gate of the semiconductor control element FET3 of the current path 2 are connected by the current path 12 via the resistance element R9. ing. Further, a semiconductor constant voltage element ZD3 is provided between the source and the gate of the semiconductor control element FET3. The semiconductor constant voltage element ZD3 is composed of a Zener diode, and utilizes the characteristic of the Zener diode that the voltage becomes constant with respect to a change in current to limit the voltage applied between the source and the gate. Therefore, it plays a role of protecting the semiconductor control element FET3 when a surge current or static electricity is generated.

Further, the connection point between the source of the semiconductor control element FET3 and the anode of the semiconductor constant voltage element ZD3, the semiconductor light emitting element LED10, and the base of the semiconductor control element TR are connected by a current path 5. A constant current diode CRD and a resistance element R6 are provided in series in the current path 6 connecting the current path 5 and the resistance element R3 and the negative power supply terminal V- of the comparator in order from the lower voltage direction. ing. One end of the resistance element R6 is connected to the negative electrode (≈GND) of the DC power supply 1. Further, the cathode of the constant current diode CRD and the resistance element R6 and the positive input terminal of the comparator are connected by a current path 7. In this way, since the constant current diode CRD and the positive input terminal of the comparator are connected by the current path 7, a predetermined voltage is input as the reference voltage (= reference voltage) from the positive side of the comparator. Further, the positive power supply terminal V + of the comparator is connected to the current path 5 by the current path 8.

Further, the semiconductor light emitting element LED10 and the resistance element R3 related to the current path 2 and the negative input terminal of the comparator are connected by the current path 9 via the resistance element R7. Further, between the negative input terminal of the comparator related to the current path 9 and the resistance element R7, and the positive dimming signal input unit S + are connected by the current path 10. A resistance element R8 and a semiconductor rectifying element D2 are connected in series in the current path 10 in order from the positive dimming signal input unit S +. Further, the resistance element R3 of the current path 2, the negative electrode (≈GND) of the DC power supply 1, and the negative dimming signal input unit S- are connected by the current path 11.

The semiconductor light emitting element LED 10 is mainly provided in the current path 2 in order to apply an operating voltage to the comparator. Specifically, a power supply is required to operate the comparator, and generally, a voltage of 5 (V) or 10 (V) is applied from the outside using a DC / DC power supply or the like. However, by providing one semiconductor light emitting element LED10 (about 3V) on the current path 2 instead of the DC / DC power supply or the like, the source of the semiconductor control element FET3 and the anode of the semiconductor constant voltage element ZD3 are connected. From the point, the voltage applied in the lower voltage direction passes through the current path 5 and is also applied to the current path 6 and the current path 8. By applying the voltage to the current path 8 in this way, the power supply voltage is applied to the comparator. Further, the semiconductor light emitting element 10 is, of course, two birds with one stone because it can emit light and play a role as one of the illumination sources in the same manner as the semiconductor light emitting elements 1 to 9.

Further, the semiconductor rectifying element D2 makes use of the characteristic that the current flows only in the forward direction so that the current passing through the resistance element R7 from the current path 2 does not flow in the direction of the positive dimming signal input unit S +. It serves to cut off the current.

Further, the semiconductor control element TR is provided for withstand voltage so that a large voltage exceeding a certain level is not applied to the comparator. Specifically, the comparator generally has a low withstand voltage, and is broken when a voltage of 100 (V) or 200 (V) is applied. Therefore, by providing the semiconductor control element TR, a voltage larger than a certain level is prevented from being applied to the comparator. By providing the semiconductor control element TR for withstand voltage, it is possible to prevent the voltage from being applied to the comparator by, for example, only about 3 (V).

Further, the positive voltage applied through the positive dimming signal input unit S + is divided by the resistance element R7 and the resistance element R8, and is divided through the current path 9 to the negative input terminal of the comparator. It is applied.

Next, the correspondence between the conceptual configuration of the present invention described with reference to FIG. 1 and the circuit configuration of the control circuit A for the lighting device described with reference to FIG. 2 will be described. The DC power supply 50 of FIG. 1 corresponds to the DC power supply 1 of FIG. Further, the LED constantly lit unit 51 of FIG. 1 corresponds to the semiconductor light emitting elements LEDs 1 to 3 of FIG. Further, the LED series-parallel conversion unit 52 of FIG. 1 corresponds to the semiconductor light emitting elements LEDs 4 to 6 and the semiconductor light emitting elements LEDs 7 to 9 of FIG. Further, the LED series-parallel control unit 53 of FIG. 1 corresponds to the semiconductor control element FET1 and the semiconductor control element FET2 of FIG. Further, the dimming signal control unit 54 of FIG. 1 corresponds to the comparator of FIG. 2, the positive dimming signal input unit S +, and the negative dimming signal input unit S−. Further, the overvoltage absorption unit 55 of FIG. 1 corresponds to the semiconductor control element FET 3 of FIG. Further, the current path 56 in FIG. 1 corresponds to the current paths 2 to 12, the current path 21, and the current path 22 in FIG.

The semiconductor light emitting elements LEDs 1 to 3 in FIG. 2, which correspond to the LED constantly lit unit 51, are for operating all FETs such as the semiconductor control elements FET1 and FET2. explain in detail. If the potential of the gate of the semiconductor control element FET1 is not higher than the potential of the source, the semiconductor control element FET1 does not turn on even if a voltage is applied to the gate, so that no current flows between the drain and the source. Therefore, by providing the LED constantly lit unit 51, the potential of the source of the semiconductor control element FET1 is lowered by the threshold voltage between the gate and the source as compared with the potential of the gate, so that the semiconductor control element FET1 operates. ..

Further, the semiconductor light emitting elements LEDs 4 to 6 and the semiconductor light emitting elements LEDs 7 to 9 of FIG. 2, which correspond to the LED series-parallel conversion unit 52, are divided into two blocks, but the connection is converted to the parallel circuit as the DC voltage drops. , In order to equalize the amount of current flowing in each current path when the current path is divided, the total impedance between the blocks is configured to be equal. If the total impedance between the blocks is different, the current may not be evenly divided when the connection is converted to the parallel circuit, and the semiconductor light emitting element LED of one block may be turned off.

Further, the semiconductor control element FET1 and the semiconductor control element FET2 in FIG. 2, which correspond to the LED series-parallel control unit 53, also have the same current flowing when the connection is converted to the parallel circuit as the DC voltage drops. The impedances of the are equal to each other.

Next, the dimming signal control unit 54 will be described in detail below. The constant current diode CRD serves as a constant voltage device, and a predetermined voltage (= reference voltage) is applied from the positive input terminal of the comparator. The constant current diode CRD is not limited as long as it plays a role as a constant voltage device. For example, a Zener diode may be used as the constant voltage device. Further, a comparator capable of outputting the reference voltage by itself may be used, and in that case, a separate constant voltage device is not required.

Further, a DC power supply or the like is connected to the positive dimming signal input unit S + and the negative dimming signal input unit S- to input a dimming signal (= control circuit for the lighting device from the outside such as the DC power supply). Apply a voltage to A). The positive voltage related to the dimming signal applied from the positive signal input unit S + is applied to the negative input terminal of the comparator because the resistance element R7 and the resistance element R8 are provided. The voltage applied to the negative input terminal of the comparator is the sum of the voltage applied from the outside such as the DC power supply and the voltage applied from the DC power supply 1.

Next, the operation of the dimming signal control unit 54 will be described in the case where the semiconductor control element FET1 is OFF and the semiconductor control element FET2 is ON.

If the voltage applied from the negative input terminal of the comparator is lower than the reference voltage applied from the positive input terminal of the comparator, the comparator draws little current. Therefore, the collector voltage of the semiconductor control element TR does not change, and the gate voltage of the semiconductor control element FET2 does not change either.

On the other hand, when the voltage applied from the negative input terminal of the comparator is higher than the reference voltage applied from the positive input terminal of the comparator, the comparator sucks the current. Specifically, the output potential of the comparator becomes negative, the current from the current path 3 is sucked in, and the sucked current is passed from the negative power supply terminal V− to the negative electrode (≈GND) of the DC power supply 1. Therefore, the collector voltage of the semiconductor control element TR drops, and the gate voltage of the semiconductor control element FET2 also drops. Then, when the gate voltage of the semiconductor control element FET 2 becomes lower than the source voltage and becomes equal to or lower than the threshold voltage between the gate and the source, the semiconductor control element FET 2 is turned off and the semiconductor light emitting elements LEDs 7 to 9 are turned on. As a result, a current flows into the semiconductor light emitting elements LEDs 7 to 9, and a forward voltage corresponding to the current flows, so that the amount of the current flowing through the entire control circuit A for the lighting device decreases.

FIG. 3 is a line graph showing the experimental results of dimming characteristics. Specifically, the "solid line" broken line shows the change in power consumption with respect to the input voltage of the dimming signal, and the "dotted line" broken line shows the change in the input current with respect to the input voltage of the dimming signal. It is a thing. Looking at the experimental results of FIG. 3, as the input voltage of the dimming signal increases, the input current (= the amount of current flowing through the entire control circuit A for the lighting device) and the power consumption (= the control circuit A for the lighting device) The total amount of electricity consumed) will decrease.

The control circuit A for the lighting device is provided with the semiconductor control element FET3 as the overvoltage absorbing unit 55. As described above, this FET 3 absorbs (= takes charge of) an excessive voltage component between the drain and the source, lowers the voltage, and sets the amount of current flowing in the control circuit A for the lighting device to a default state. Play a role in keeping.

Therefore, in the control circuit A for the lighting device, after the LEDs 1 to 9 are turned on by the input of the dimming signal, the input voltage of the dimming signal is further increased to reduce the current flowing through the entire control circuit A. , Dimmable. On the other hand, when the FET 3 is not provided as the overvoltage absorbing unit 55, the current flowing through the entire control circuit A is further reduced from the state in which all the LEDs in the control circuit A for the lighting device are lit to dimming. You can't.

Next, the operation of the control circuit A for the lighting device will be described with reference to FIGS. 2, 4, and 5. When a sufficient voltage is applied from the DC power supply 1 (for example, 29.3V), a sufficient base current flows through the semiconductor control element TR, the semiconductor control element TR is turned on, and the collector voltage of the semiconductor control element TR is increased. Since the gate voltages of the semiconductor control element FET1 and the semiconductor control element FET2 are equal at 0V, the semiconductor control element FET1 and the semiconductor control element FET2 are not turned on. Therefore, as shown in FIG. 4, the current flowing through the semiconductor light emitting elements LEDs 1 to 3 is the semiconductor light emitting elements LEDs 4 to 6 in the current path 21, the semiconductor rectifying element D1, the semiconductor light emitting elements LEDs 7 to 9 in the current path 22, and semiconductor control. It flows through the element FET3, the semiconductor light emitting element LED10, and the resistance element R3. That is, the semiconductor light emitting elements LEDs 4 to 6 and the semiconductor light emitting elements LEDs 7 to 9 are connected in series.

Then, as the voltage from the DC power supply 1 decreases (for example, 27.4V), the base current of the semiconductor control element TR decreases, and the collector current of the semiconductor control element TR also decreases. Then, although the semiconductor control element TR is turned on, the voltage value at which the collector voltage of the semiconductor control element TR and the gate voltage of the semiconductor control element FET1 and the semiconductor control element FET2 become equal increases, and the source of the semiconductor control element FET2 When the voltage becomes higher than the voltage and exceeds the gate-source threshold voltage of the semiconductor control element FET2, the semiconductor control element FET2 is turned on. Therefore, as shown in FIG. 5, the current flowing through the semiconductor light emitting elements LEDs 1 to 3 is the semiconductor light emitting elements LEDs 4 to 6 in the current path 21, the semiconductor control element FET 2, the semiconductor control element FET 3, the semiconductor light emitting element LED 10, and the resistance element R3. Flow to. On the other hand, the semiconductor light emitting elements LEDs 7 to 9 in the current path 22 are turned off.

In such a state, a voltage is applied from the outside through the positive dimming signal input unit S + and the negative dimming signal input unit S-, and the voltage applied from the negative input terminal of the comparator is the positive voltage of the comparator. Make sure that the voltage is higher than the reference voltage applied from the input terminal. As a result, the comparator sucks the current, the collector voltage of the semiconductor control element TR drops, and the gate voltage of the semiconductor control element FET2 also drops. Then, when the gate voltage of the semiconductor control element FET 2 becomes lower than the source voltage and the threshold voltage between the gate and the source becomes less than or equal to that, the semiconductor control element FET 2 is turned off and the semiconductor light emitting elements LEDs 7 to 9 are turned on. As a result, a current flows into the semiconductor light emitting elements LEDs 7 to 9, and a forward voltage corresponding to the current flows, so that the amount of the current flowing through the entire control circuit A for the lighting device decreases.

Next, when the voltage from the DC power supply 1 is insufficient (for example, 19.9 V or less), the base current of the semiconductor control element TR is further reduced, and the collector current of the semiconductor control element TR is also reduced. Then, although the semiconductor control element TR is turned on, the voltage value at which the collector voltage of the semiconductor control element TR and the gate voltage of the semiconductor control element FET1 and the semiconductor control element FET2 are equal to each other further increases, and the source voltage of the semiconductor control element FET1 is further increased. When the voltage exceeds the gate-source threshold voltage of the semiconductor control element FET1, the semiconductor control element FET1 is turned on. Alternatively, the semiconductor control element TR is turned off and the semiconductor control element FET1 is turned on. Therefore, as shown in FIG. 6, the current flowing through the semiconductor light emitting elements LEDs 1 to 3 is the route flowing through the semiconductor light emitting elements LEDs 4 to 6 of the current path 21 and the semiconductor control element FET 2 and the semiconductor control element FET 1 of the current path 22. It is divided into routes that flow through the semiconductor light emitting elements LEDs 7 to 9. That is, the semiconductor light emitting elements LEDs 4 to 6 and the semiconductor light emitting elements LEDs 7 to 9 are connected in parallel. Since the total impedance of the semiconductor light emitting elements LEDs 4 to 6 and the semiconductor control element FET 2 of the current path 21 connected in parallel is equal to the total impedance of the semiconductor control element FET 1 and the semiconductor light emitting element LEDs 7 to 9 of the current path 22, the semiconductor The amounts of current flowing through the light emitting elements LEDs 4 to 6 and the semiconductor light emitting elements LEDs 7 to 9 are equal.

In such a state, a voltage is applied from the outside through the positive dimming signal input unit S + and the negative dimming signal input unit S-, and the voltage applied from the negative input terminal of the comparator is the positive voltage of the comparator. Make sure that the voltage is higher than the reference voltage applied from the input terminal. As a result, the comparator sucks the current, the collector voltage of the semiconductor control element TR drops, and the gate voltage of the semiconductor control element FET1 and the semiconductor control element FET2 also drops. When the gate voltage of the semiconductor control element FET1 becomes lower than the source voltage and becomes equal to or lower than the threshold voltage between the gate and the source, the semiconductor control element FET1 is turned off and the semiconductor light emitting elements LEDs 4 to 6 are connected in series with the LEDs 1 to 3. LEDs 7 to 9 are turned off.

Further, the voltage applied from the outside is increased through the positive dimming signal input unit S + and the negative dimming signal input unit S−. As a result, the comparator further sucks the current, the collector voltage of the semiconductor control element TR further decreases, and the gate voltage of the semiconductor control element FET1 and the semiconductor control element FET2 also decreases. Then, when the gate voltage of the semiconductor control element FET 2 becomes lower than the source voltage and the threshold voltage between the gate and the source becomes less than or equal to that, the semiconductor control element FET 2 is turned off and the semiconductor light emitting elements LEDs 7 to 9 are turned on.

As a result, the semiconductor light emitting elements LEDs 4 to 9 are connected in series, a current flows into the semiconductor light emitting elements LEDs 7 to 9, and a forward voltage corresponding to the current flows, so that the current flows through the entire control circuit A for the lighting device. The amount of current is further reduced.

As in the control circuit A for the lighting device of FIG. 2, the number of semiconductor light emitting element LEDs related to the LED constantly lit unit 51 (three of the semiconductor light emitting elements LEDs 1 to 3) and the LED series-parallel conversion unit 52 are related. , The ratio of the number of semiconductor light emitting element LEDs (three semiconductor light emitting element LEDs 4 to 6 or semiconductor light emitting element LEDs 7 to 9) of each block when the connection is converted to the parallel circuit and the current path is divided is 1: 1. In the case of, when the voltage from the DC power supply 1 becomes about 2/3 (when the voltage from the DC power supply 1 decreases by about 1/3), the connection is converted from the series circuit to the parallel circuit.

Further, in the above-described embodiment, the operation of the control circuit A for the lighting device has been described as an example in which the voltage from the DC power supply 1 decreases or becomes insufficient. However, the control circuit A for the lighting device does not have a configuration that can be used only when the voltage from the DC power supply 1 decreases or becomes insufficient, and the semiconductor light emitting element LED related to the LED series-parallel conversion unit 52 is serially-parallel. By converting the connection, it is a configuration that can correspond to a wide range of voltage applied by the DC power supply 1. Therefore, for example, the voltage from the DC power supply 1 is insufficient, and the semiconductor light emitting element LED related to the LED series-parallel conversion unit 52 is connected in parallel, the voltage is increased, and a sufficient voltage is applied. In the case of shifting to, the connection of the semiconductor light emitting element LED related to the LED series-parallel conversion unit 52 is converted from parallel to series.

With such a configuration, the semiconductor light emitting element according to the control circuit A for the lighting device is applied by applying a voltage from the outside through the positive dimming signal input unit S + and the negative dimming signal input unit S-. The LED can be dimmed, which is convenient. Further, by dimming the semiconductor light emitting element LED related to the control circuit A for the lighting device, the total amount of the voltage applied to the semiconductor light emitting element LED can be adjusted, and the control circuit A for the lighting device can be adjusted. It is convenient because the amount of flowing current can be adjusted.

Further, by automatically converting the series-parallel connection of the semiconductor light emitting element LED related to the LED series-parallel conversion unit 52 according to the fluctuation of the voltage of the DC power supply 50, a wide range of power supply voltages can be obtained without using a power supply conversion unit. It is possible to correspond to the range of. Further, since the semiconductor control element FET3 related to the overvoltage absorbing unit 55 is provided, it has a protection function against overvoltage. Further, the amount of current supplied from the DC power supply 50 is increased by automatically converting the series-parallel connection of the semiconductor light emitting element LEDs related to the LED series-parallel conversion unit 52 according to the fluctuation of the voltage of the DC power supply 50. It becomes almost constant.

In addition, since the configuration does not use a power conversion unit, it is possible to reduce the size, efficiency, and price of the lighting device. In addition, it does not generate electromagnetic noise and can be used in environments such as hospitals and precision machine rooms where electromagnetic noise is disliked. Furthermore, the risk of failure of the lighting device can be reduced.

Further, since the configuration is such that the series-parallel connection of the semiconductor light emitting element LEDs related to the LED series-parallel conversion unit 52 is automatically converted according to the fluctuation of the voltage of the DC power supply 50, most of the LEDs in the control circuit are turned off. It is difficult for people around you to notice fluctuations in the power supply voltage.

(Modification example)
In the first embodiment, the LED series-parallel conversion unit 52 shows a configuration in which a block related to the semiconductor light emitting elements LEDs 4 to 6 and a block related to the semiconductor light emitting elements LEDs 7 to 9 are stacked in two stages. It is not limited. If the LED constantly lit unit 51 is provided and the semiconductor control element FET 1 having the highest potential among the semiconductor control element FETs in the control circuit can be turned on, the number of blocks related to the semiconductor light emitting element LED in the LED series-parallel conversion unit 52 is increased. Can also be stacked in series. For example, as shown in FIG. 7, as the LED series-parallel conversion unit 52, a block related to the semiconductor light emitting element LED4, a block related to the semiconductor light emitting element LED5, a block related to the semiconductor light emitting element LED6, and a block related to the semiconductor light emitting element LED7 are arranged in four stages. It may be configured to be stacked. By stacking the blocks related to the semiconductor light emitting element LED in the LED series-parallel conversion unit 52 in series, the range that can respond to the voltage fluctuation of the DC power supply is expanded, and it is possible to cope with the large fluctuation of the power supply voltage. It is convenient.

Further, in the first embodiment, in each block related to the semiconductor light emitting element LED in the LED series-parallel conversion unit 52, three LEDs such as the semiconductor light emitting element LEDs 4 to 6 and the semiconductor light emitting elements LEDs 7 to 9 are provided. Although the configuration is shown, the configuration is not limited to this configuration, and the number of semiconductor light emitting element LEDs in each block in the LED series-parallel conversion unit 52 may be any number. For example, as shown in FIG. 7, the number of semiconductor light emitting element LEDs in each block in the LED series-parallel conversion unit 52 may be small (for example, one). The total of the forward (direction) voltage values required for lighting the semiconductor light emitting element LEDs of each block in the LED series-parallel conversion unit 52 is the voltage value at which the series-parallel connection is converted. Therefore, when the number of semiconductor light emitting element LEDs in each block in the LED series-parallel conversion unit 52 is small, the power supply voltage corresponding to the forward (direction) voltage of a small number of semiconductor light emitting element LEDs is changed. The series-parallel connection is converted, and the resolution and sensitivity are high. On the other hand, for example, when the number of semiconductor light emitting element LEDs in each block in the LED series-parallel conversion unit 52 is large, it responds to fluctuations in the power supply voltage corresponding to the forward (direction) voltage of many semiconductor light emitting element LEDs. Therefore, the series-parallel connection is converted, and the series-parallel connection is converted according to a large change in the power supply voltage.

Further, the number of semiconductor light emitting element LEDs in each block in the LED series-parallel conversion unit 52 may be different. For example, as shown in FIG. 8, the number of semiconductor light emitting element LEDs in each block in the LED series-parallel conversion unit 52 is one (semiconductor light emitting element LEDs 4, 5) and three (semiconductor light emitting element LEDs 6 to 8, 9 to 12). ), Two (semiconductor light emitting elements LEDs 13 to 14, 15 to 16) may be used. However, when the connection is converted from series to parallel due to the shortage of the power supply voltage and the current path is divided, the impedances of the semiconductor light emitting element LEDs (for example, semiconductor light emitting elements LEDs 4 and 5) that are in a corresponding relationship are the same. Must be the same number.

In the first embodiment, the semiconductor light emitting elements LEDs 1 to 3 are provided as the LED constantly lit unit 51 at a potential higher than that of the semiconductor control element FET 1 so that the semiconductor control element FET 1 can be turned on. In addition to the LED constantly lit unit 51 at this position, one or a plurality of LED constantly lit units 51 may be separately provided. For example, as shown in FIG. 9, between the LED series-parallel conversion unit 52 composed of the semiconductor light-emitting elements LEDs 4 to 9 and the LED series-parallel conversion unit 52 composed of the semiconductor light-emitting elements LEDs 13 to 16, semiconductor light emission is performed as an LED constantly lit unit 51. The elements LEDs 11 and 12 may be provided. This is convenient because when the power supply voltage is insufficient, the points that are converted from series to parallel (= the points where the flowing current is halved) can be dispersed, and the difference in brightness of the lighting device can be reduced.

In the first embodiment of the present embodiment, a two-parallel configuration in which the current path is divided into two when the connection is converted from series to parallel due to insufficient power supply voltage is shown, but the configuration is limited to this configuration. is not. For example, as shown in FIG. 10, a 4-parallel configuration in which the current path is divided into four may be used, or an 8-parallel, 16-parallel, or 32-parallel configuration may be used. This is convenient because the semiconductor light emitting element LED related to the LED series-parallel conversion unit 52 can be turned on even with a smaller power supply voltage.

In the first embodiment of the present embodiment, a configuration using a comparator as a comparator for comparing input voltages is shown, but the configuration is not limited to this configuration. For example, an operational amplifier may be used instead of the comparator. When an operational amplifier is used, the operational amplifier generally has a high withstand voltage, so that the semiconductor control element TR for withstand voltage is not required.

Then, when the voltage applied from the negative input terminal of the operational amplifier is lower than the reference voltage applied from the positive input terminal of the operational amplifier, the operational amplifier outputs a positive voltage and outputs a small amount of current. Do not inhale. Therefore, the gate voltage of the semiconductor control element FET2 and the like does not change.

On the other hand, when the voltage applied from the negative input terminal of the operational amplifier is higher than the reference voltage applied from the positive input terminal of the operational amplifier, the operational amplifier outputs a negative voltage and sucks the current. Therefore, the gate voltage of the semiconductor control element FET2 or the like drops.

Further, in the control circuit A for the lighting device according to the first embodiment, the semiconductor control element FET3, the resistance element R9, and the semiconductor constant voltage element ZD3 are provided, and an excessive voltage component exceeding a predetermined voltage value is controlled by the semiconductor. The configuration is shown in which the element FET3 takes charge of the voltage drop to protect the control circuit A for the lighting device, but the present invention is not limited to this configuration, and the semiconductor control element FET3, the resistance element R9, and the semiconductor constant voltage element ZD3 are not limited to this configuration. It may be configured not to provide.

Further, in the control circuit A for the lighting device according to the first embodiment, a configuration in which the semiconductor control element FET3, which is a field effect transistor (= Field Effect Transistor), is used as the overvoltage absorbing unit 55 has been shown. It is not limited to the configuration. For example, the overvoltage absorbing unit 55 may be configured to use a PNP type or NPN type bipolar transistor, or may be configured to use an insulated gate bipolar transistor (= IGBT). Further, the semiconductor control element FET 3 includes various FETs such as a junction FET (= JFET) and a MOS-FET. That is, the overvoltage absorbing unit 55 may be an element or the like that plays a role of lowering the voltage of the excessive voltage when an excessive voltage exceeding a predetermined voltage value is applied from the DC power supply 1.

(Example 2 of the embodiment)
In the above-described first embodiment, the positive dimming signal input unit S + and the negative dimming signal are used for the configuration in which the series-parallel connection of the semiconductor light emitting element LEDs is converted according to the increase or decrease of the voltage of the DC power supply. An example is shown in which the configuration of the dimming signal control unit 54 that dims the semiconductor light emitting element LED by applying a voltage from the outside through the input unit S- is applied. On the other hand, in the second embodiment, an example is shown in which the configuration of the dimming signal control unit 54 is applied to the configuration of controlling the lighting / extinguishing of the semiconductor light emitting element LED according to the increase / decrease of the voltage of the DC power supply.

First, it will be described with reference to FIG. 11, which is a conceptual configuration diagram of the second embodiment of the present invention. The control circuit for the lighting device of the present invention is provided with an LED constantly lit unit 51 in which the LED is constantly lit by applying the voltage of the DC power supply 50, and the LED is turned on and off by the fluctuation of the voltage value of the DC power supply 50. An on / off unit 62 is provided, and an LED on / off control unit 63 for turning on / off the LED related to the LED on / off unit 62 according to the fluctuation of the voltage value of the DC power supply 50 is provided, and further, dimming from the outside. A dimming signal control unit 54 that receives a signal input and performs dimming control according to the dimming signal is provided. Further, each part is connected through a current path 55.

With this configuration, the LEDs related to the LED constant lighting unit 51 and the LED lighting / extinguishing unit 62 are lit by the DC voltage supplied from the DC power supply 50, but when the voltage of the DC power supply 50 drops, the LED lighting / extinguishing control is performed. The unit 63 operates, and the LED related to the LED on / off unit 62 is turned off. As a result, the current flowing through the LED can be kept constant.

Next, the configuration of the control circuit B for the lighting device according to the second embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 12, a current path 12 in which semiconductor light emitting elements LEDs 1 to LED 5 made of LEDs are connected in series in the same polar direction and a current path 13 provided with a resistance element R1 are respectively on both sides of the DC power supply 1. It is connected. Further, a dimming signal control unit 54 is provided between the end of the current path 12 and the end of the current path 13.

Semiconductor control elements FETs 4 to 6 are connected in parallel between the anodes and cathodes of the semiconductor light emitting elements LEDs 3 to 5, respectively. Each gate of each of the semiconductor control elements FETs 4 to 6 is connected to a collector of the semiconductor control element TR related to the dimming signal control unit 54 via semiconductor rectifying elements D3 to 5, respectively. The anodes of these semiconductor rectifying elements D3 to 5 are connected to the collector of the semiconductor control element TR, and the cathodes of the semiconductor rectifying elements D3 to 5 are connected to the gates of the semiconductor element FETs 4 to 6, respectively. Further, resistance elements R2, R4, and R9 are provided between the source end and the gate end of the semiconductor control elements FETs 4 to 6, respectively.

These resistance elements R2, R4, and R9 limit the voltage applied between the source and the gate. Therefore, it plays a role of protecting the semiconductor control elements FETs 4 to 6 when a surge current or static electricity is generated.

Since the configuration and operation of the dimming signal control unit 54 are described in the above-described first embodiment, the description thereof will be omitted here.

Next, the correspondence between the conceptual configuration of the second embodiment of the present invention described with reference to FIG. 11 and the circuit configuration of the control circuit B for the lighting device described with reference to FIG. 12 will be described. The DC power supply 50 of FIG. 11 corresponds to the DC power supply 1 of FIG. Further, the LED constantly lit unit 51 of FIG. 11 corresponds to the semiconductor light emitting elements LEDs 1 and 2 of FIG. Further, the LED lighting / extinguishing unit 62 of FIG. 11 corresponds to the semiconductor light emitting elements LEDs 3 to 5 of FIG. Further, the LED lighting / extinguishing control unit 63 of FIG. 11 corresponds to the semiconductor control elements FETs 4 to 6 of FIG. Further, the dimming signal control unit 54 of FIG. 11 corresponds to the comparator of FIG. 12, the positive dimming signal input unit S +, and the negative dimming signal input unit S−. Further, the current paths 55 in FIG. 11 correspond to the current paths 5 to 13 in FIG.

Next, the operation of the control circuit B for the lighting device will be described. When the voltage applied from the DC power supply 1 has a predetermined voltage value, all the semiconductor light emitting elements LEDs 1 to LED 5 are lit. At that time, the base of the semiconductor control element TR is in a forward bias state, and the semiconductor control element TR is in a conductive state. Then, the collector of the semiconductor control element TR and the gates of the semiconductor control elements FETs 4 to 6 have the same potential in a low state, and the semiconductor control elements FETs 4 to 6 do not conduct.

On the other hand, when the voltage value of the DC power supply 1 decreases, the base of the semiconductor control element TR does not become a forward bias state, and the potential of the collector increases. Along with this, the potential of each gate of the semiconductor control elements FETs 4 to 6 also rises. As a result, the potential of the gate becomes higher than the source potential, and the semiconductor control elements FETs 4 to 6 are turned on in the order of the semiconductor control elements FETs 6, 5 and 4 (according to the degree of increase in the potential), and each semiconductor control element FET4 to 4 to A current flows between the drain and the source of 6, and the semiconductor light emitting elements LEDs 3 to 5 corresponding to these semiconductor control elements FETs 4 to 6 are turned off in the order of the semiconductor light emitting elements 5, 4, and 3.

In such a state, a voltage is applied from the outside through the positive dimming signal input unit S + and the negative dimming signal input unit S-, and the voltage applied from the negative input terminal of the comparator is the positive voltage of the comparator. Make sure that the voltage is higher than the reference voltage applied from the input terminal. As a result, the comparator sucks the current, the potential of the collector of the semiconductor control element TR drops, and the potential of the gates of the semiconductor control elements FETs 4 to 6 also drops. Then, when the potential of the gate of the semiconductor control elements FETs 4 to 6 becomes lower than the potential of the source and becomes equal to or less than the threshold voltage between the gate and the source, the semiconductor control elements FETs 4 to 6 are turned off in the order of 4, 5 and 6. Therefore, the semiconductor light emitting elements LEDs 3 to 5 light up in the order of 3, 4, and 5. As a result, a current flows into the semiconductor light emitting elements LEDs 3 to 5, and a forward voltage corresponding to the current flows, so that the amount of the current flowing through the entire control circuit B for the lighting device is reduced.

With such a configuration, the semiconductor light emitting element according to the control circuit B for the lighting device is applied by applying a voltage from the outside through the positive dimming signal input unit S + and the negative dimming signal input unit S-. The LED can be dimmed, which is convenient. Further, by dimming the semiconductor light emitting element LED related to the control circuit B for the lighting device, the total amount of the voltage applied to the semiconductor light emitting element LED can be adjusted, and the control circuit B for the lighting device can be adjusted. It is convenient because the amount of flowing current can be adjusted.

(Example 3 of the present embodiment)
In Example 2 of the present embodiment described above, an example is shown in which the configuration of the dimming signal control unit 54 is applied to the configuration of controlling the lighting / extinguishing of the semiconductor light emitting element LED according to the increase / decrease of the voltage of the DC power supply. .. On the other hand, in the third embodiment of the present embodiment, the lighting / extinguishing of the semiconductor light emitting element LED is controlled according to the increase / decrease of the voltage of the DC power supply, and even if the voltage of the DC power supply decreases, the lighting device as a whole is bright. An example in which the configuration of the dimming signal control unit 54 is applied to the configuration that does not cause a bias is shown.

First, it will be described with reference to FIG. 13, which is a conceptual configuration diagram of the third embodiment of the present invention. The control circuit for the lighting device of the present invention is provided with an LED constantly lit unit 51 in which the LED is constantly lit by applying the voltage of the DC power supply 50, and the LED is turned on and off by the fluctuation of the voltage value of the DC power supply 50. A lighting / extinguishing unit 62 is provided, and an LED lighting / extinguishing control unit 63 for turning on / off the LED related to the LED lighting / extinguishing unit 62 according to the fluctuation of the voltage value of the DC power supply 50 is provided. A photoconductive unit 64 for transmitting the current value flowing through the LED related to the control circuit to the LED lighting / extinguishing control unit 63 is provided, and further, a dimming signal input is received from the outside, and dimming control is performed by the dimming signal. , The dimming signal control unit 54 is provided. Further, each part is connected through a current path 55.

Next, the configuration of the control circuit C for the lighting device according to the third embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 14, the control circuit C for the lighting device includes a DC power supply 1 to which a DC voltage is applied, an LED light emitting block 80 in which an provided LED emits light, and a dimming signal control for controlling the LED light emitting block 80. It is mainly composed of a part 54. Each LED light emitting block 80 and the dimming signal control unit 54 have circuit elements arranged on one substrate, and adjacent blocks are electrically connected to each other. Then, as shown in FIG. 14, the LED light emitting block 80 is arranged at a position close to the DC power supply 1 and having a high potential, and the dimming signal control unit is located far from the DC power supply 1 and has a lower potential than any of the LED light emitting blocks 80. Place 54. Further, the DC power supply 1, the LED light emitting block 80, and the circuit elements arranged in the dimming signal control unit 54 form a closed circuit. In the example of the present embodiment, a configuration using four LED light emitting blocks 80 is shown, but the present invention is not limited to this configuration, and the LED light emitting blocks 80 may be single or plural. Is also good.

The LED light emitting block 80 has a current path H in which the light emitting element 82 of the photoconductive element 81 is connected in series, and a current path I in which the resistance element 88 and the light receiving element 83 of the photoconductive element 81 are connected in series. The photoconductive element 81 is a photocoupler in this embodiment. Therefore, the photoconductive element 81 has a structure in which a light emitting element 82 such as an LED and a light receiving element 83 such as a phototransistor are housed inside, and is enclosed in a package 84 that blocks light from the outside. The photoconductive element 81 converts the input current into light by the light emitting element 82, and the light receiving element 83 receives the light to transmit the current. Further, the resistance element 88 is for allowing a small amount of current from the DC power supply 1 to flow in the current path I and most of the current from the DC power supply 1 to flow in the current path K (described later).

Further, the LED light emitting block 80 has a current path K in which semiconductor light emitting elements 86 are connected in series in the same polar direction. The semiconductor light emitting device 86 is an LED in this embodiment. In this embodiment, the semiconductor control element 85, which is an N-channel enhancement type FET (= field effect transistor), is connected in parallel to the semiconductor light emitting element 86. Specifically, the drain at one end of the semiconductor control element 85 (indicated as “D” in FIG. 14) is connected to the anode at one end of the semiconductor light emitting element 86, and the source at one end of the semiconductor control element 85 (shown as “D”). The semiconductor control element 85 is connected in parallel to the semiconductor light emitting device 86 by connecting the cathode (indicated as “S” in FIG. 14) and the cathode at one end of the semiconductor light emitting element 86. However, as shown in FIG. 14, the semiconductor control element 85 is connected in parallel to the semiconductor light emitting element 86 among the semiconductor light emitting elements 86 in the current path K of each LED light emitting block 80, the DC power supply 1 Not from the semiconductor light emitting device 86 (“LED1” in FIG. 14) closest to the highest potential, but from the second semiconductor light emitting device 86 (“LED2” in FIG. 14) adjacent to the semiconductor light emitting device 86. is there. Further, the drain and the source of the semiconductor control element 85 are parallel to the semiconductor light emitting element 86 arranged in the current path K at predetermined intervals (for example, every other one with respect to the semiconductor light emitting element 86 in FIG. 14). It is connected to the. Therefore, the semiconductor light emitting element 86, the semiconductor control element 85, the semiconductor light emitting element 86, the semiconductor light emitting element 86, the semiconductor control element 85, and the semiconductor light emitting element 86 are arranged in order from the one closest to the DC power source 1 and having the highest potential. In the third embodiment, the drain and the source of the semiconductor control element 85 are connected in parallel to the semiconductor light emitting element 86, but the present invention is not limited to this configuration. For example, the drain and source of the semiconductor control element 85 may be connected in parallel to the semiconductor light emitting element 86 every two or every three elements. Further, in the third embodiment, the semiconductor control element 85 is the second semiconductor light emitting element in the current path K of each LED light emitting block 80, which is closer to the DC power supply 1 and has the highest potential. Although the configuration in which the semiconductor light emitting elements 86 are connected in parallel is shown, the configuration is not limited to this configuration, and any configuration may be used as long as it is connected in parallel from the second and subsequent semiconductor light emitting elements 86.

Further, the light receiving element 83 of the photoconductive element 81 and the gate of each semiconductor control element 85 (indicated as “G” in FIG. 14) are electrically connected via the rectifying element 87. The rectifying element 87 is a diode in the present embodiment, and the anode is connected to the light receiving element 83 and the cathode is connected to the gate of the semiconductor control element 85. Therefore, a current flows from the light receiving element 83 to the gate of the semiconductor control element 85, but almost no current flows from the gate of the semiconductor control element 85 in the opposite direction to the light receiving element 83. By interposing the rectifying element 87, it is possible to prevent the risk of a current exceeding an allowable value flowing through the light receiving element 83. The rectifying element 87 is not limited to the diode, and a current flows from the light receiving element 83 to the gate of the semiconductor control element 85, but from the gate of the semiconductor control element 85 in the opposite direction to the light receiving element 83. Is an element having a rectifying function that hardly causes a current to flow.

Further, in the example of the present embodiment, a configuration in which two semiconductor control elements 85 and four semiconductor light emitting elements 86 are arranged in each LED light emitting block 80 is shown. As described above, the semiconductor light emitting element 86 having the highest potential closest to the DC power supply 1 in the current path K (“LED1” in FIG. 14) and the semiconductor light emitting element 86 having the lowest potential farthest (“LED4” in FIG. 14)). It is necessary to select the number of the semiconductor control element 85 and the semiconductor light emitting element 86 so that the potential difference between the two is within the rated range of the gate-source voltage of the semiconductor control element 85 (for example, within 20 (V)). .. Therefore, the number of the semiconductor control element 85 and the semiconductor light emitting element 86 is not limited as long as it is within the rated range of the gate-source voltage of the semiconductor control element 85, and any number may be used.

Since the configuration and operation of the dimming signal control unit 54 are described in the above-described first embodiment, the description thereof will be omitted here.

Next, the correspondence between the conceptual configuration of the third embodiment of the present invention described with reference to FIG. 13 and the circuit configuration of the control circuit C for the lighting device described with reference to FIG. 14 will be described. The DC power supply 50 of FIG. 13 corresponds to the DC power supply 1 of FIG. Further, the LED constantly lit unit 51 of FIG. 13 corresponds to the LED1 and the LED3 related to the semiconductor light emitting element 86 of FIG. Further, the LED on / off unit 62 in FIG. 13 corresponds to the LED 2 and the LED 4 related to the semiconductor light emitting element 86 in FIG. Further, the LED lighting / extinguishing control unit 63 of FIG. 13 corresponds to the FET 1 and the FET 2 related to the semiconductor control element 85 of FIG. Further, the photoconductive portion 64 of FIG. 13 corresponds to the photoconductive element 81 of FIG. Further, the dimming signal control unit 54 of FIG. 13 corresponds to the comparator of FIG. 14, the positive dimming signal input unit S +, and the negative dimming signal input unit S−. Further, the current path 55 in FIG. 13 corresponds to the current paths H, I and K in FIG.

Next, the operation of the control circuit C for the lighting device will be described. A positive electrode potential is applied from the DC power supply 1, and a negative electrode potential which is a reference potential (0 potential) is applied to the ground (= GND). If the positive electrode potential applied from the DC power supply 1 with respect to the reference potential is equal to or greater than the sum of the potential barrier values of the semiconductor light emitting elements 86 connected in series in the same polar direction in the control circuit C for the lighting device, all semiconductors The light emitting element 86 emits light. The potential barrier value of the semiconductor light emitting device 86 is a unique forward voltage drop value of the semiconductor light emitting device 86.

When the voltage applied from the DC power supply 1 decreases and the current flowing through the control circuit C for the lighting device decreases from a predetermined value, the current flowing through the light emitting element 82 of the photoconductive element 81 of each LED light emitting block 80 decreases. , The light receiving element 83 works in the direction of turning off, and the voltage between the collector and the emitter increases. As a result, the semiconductor control element 85 is turned on (= current flows from the drain to the source), and the semiconductor light emitting element 86 installed in parallel with the semiconductor control element 85 is turned off. The forward falling potential of the semiconductor light emitting device 86 that has been turned off becomes approximately 0 (V). As the number of semiconductor light emitting elements 86 that are turned off increases with respect to the voltage applied from the DC power supply 1, the potential barrier value of the semiconductor light emitting elements 86 connected in series in the same polar direction in the control circuit C for the lighting device As the total of the above decreases, the current flowing through the control circuit C for the lighting device increases, and when the specified value is reached, that value is maintained.

In such a state, a voltage is applied from the outside through the positive dimming signal input unit S + and the negative dimming signal input unit S-, and the voltage applied from the negative input terminal of the comparator is the positive voltage of the comparator. Make sure that the voltage is higher than the reference voltage applied from the input terminal. As a result, the comparator sucks the current, the current flowing through the light emitting element 82 of the photoconductive element 81 of each LED light emitting block 80 decreases, the light receiving element 83 works in the direction of turning off, and the voltage between the collector and the emitter increases. Then, the collector voltage of the light receiving element 83 drops, and the gate voltage of each semiconductor control element 85 also drops. Then, when the gate voltage of the semiconductor control element 85 becomes lower than the source voltage and becomes equal to or lower than the threshold voltage between the gate and the source, the semiconductor control element 85 is turned off in the order of FET1 and FET2, and the semiconductor light emitting element 86 is turned off. It lights up in the order of LED2 and LED4. As a result, a current flows into the semiconductor light emitting elements 86 (LEDs 2 and 4), and a forward voltage corresponding to the current flows, so that the amount of the current flowing through the entire control circuit C for the lighting device is reduced.

On the other hand, when the voltage applied from the DC power supply 1 rises and the current flowing through the control circuit C for the lighting device increases from a predetermined value, the current flowing through the light emitting element 82 of the photoconductive element 81 of each LED light emitting block 80 increases. The voltage increases, the light receiving element 83 works in the direction of turning on, and the voltage between the collector and the emitter decreases. As a result, the semiconductor control element 85 is turned off (= no current flows from the drain to the source), and the semiconductor light emitting element 86 installed in parallel with the semiconductor control element 85 lights up. The forward falling potential of the lit semiconductor light emitting device 86 is a number (V). As the number of lighting semiconductor light emitting elements 86 increases with respect to the voltage applied from the DC power supply 1, the potential barrier value of the semiconductor light emitting elements 86 connected in series in the same polar direction in the control circuit C for the lighting device As the sum of the above increases, the current flowing through the control circuit C for the lighting device decreases, and when a predetermined value is reached, that value is maintained.

With such a configuration, a semiconductor light emitting element related to a control circuit C for a lighting device is applied by applying a voltage from the outside through a positive dimming signal input unit S + and a negative dimming signal input unit S-. The LED can be dimmed, which is convenient. Further, by dimming the semiconductor light emitting element LED related to the control circuit C for the lighting device, the total amount of the voltage applied to the semiconductor light emitting element LED can be adjusted, and the control circuit C for the lighting device can be adjusted. It is convenient because the amount of flowing current can be adjusted.

Further, in the control circuit C for the lighting device, even if the power supply voltage fluctuates, the current flowing through the semiconductor light emitting element 86 can be kept constant by turning the semiconductor control element 85 and the semiconductor light emitting element 86 ON / OFF. The quality of the light output from the lighting device is not deteriorated, or the semiconductor light emitting element is deteriorated due to the fluctuation of the current, and the life is not shortened. Further, since the semiconductor control elements 85 are connected in parallel to the semiconductor light emitting elements 86 arranged in series at predetermined intervals, a part of the semiconductor light emitting elements 86 is turned off when the power supply voltage drops. However, since the semiconductor light emitting elements 86 are not turned off in a cohesive area and the semiconductor light emitting elements 86 that are turned off are dispersed, the brightness of the lighting device is not biased.

(Modification example)
In the control circuit C according to the third embodiment, the semiconductor control element 85 is connected in parallel to the semiconductor light emitting element 86 arranged in the current path K at predetermined intervals, so that the potential is increased. A configuration is realized in which the semiconductor light emitting element 86, the semiconductor control element 85, the semiconductor light emitting element 86, the semiconductor light emitting element 86, the semiconductor control element 85, and the semiconductor light emitting element 86 are arranged in descending order. However, the configuration is not limited to this, and the semiconductor light emitting element 86, the semiconductor light emitting element 86, and the semiconductor control element 85 are placed on the current path in descending order of potential, as in the control circuit D for the lighting device shown in FIG. And the semiconductor light emitting element 86, the semiconductor control element 85, and the semiconductor light emitting element 86, but by wiring, the semiconductor light emitting element 86, the semiconductor control element 85 and the semiconductor light emitting element 86, the semiconductor light emitting element 86, the semiconductor control element 85 and It may be configured to realize a configuration arranged with the semiconductor light emitting element 86. With such a configuration, when the power supply voltage drops, a part of the semiconductor light emitting element 86 of the lighting device is turned off, but the semiconductor light emitting element 86 that is not turned off in the area where the semiconductor light emitting element 86 is gathered is turned off. scatter. That is, from the appearance of the lighting device, it seems that every other semiconductor light emitting element 86 is turned off. Therefore, the brightness of the lighting device is not biased.

Further, in the configuration in which the control circuit C for the lighting device according to the third embodiment has a plurality of LED light emitting blocks 80, the semiconductor light emitting element 86 at the end of the light emitting block 80 and the end of the adjacent light emitting block 80 It is desirable that the distance between the semiconductor light emitting elements 86 of the above is the same as the distance between the semiconductor light emitting elements 86 arranged in the LED light emitting block 80. Here, "similar" is a concept including an error of about the same to several centimeters. With such a configuration, when the LED light emitting block 80 is composed of a plurality of substrates and the power supply voltage drops and a part of the semiconductor light emitting elements 86 of the lighting device is turned off, every other LED light emitting block 80 appears in the appearance of the lighting device. It seems that the semiconductor light emitting element 86 is turned off. Therefore, the brightness of the lighting device is not biased.

Further, in the control circuit C for the lighting device according to the present embodiment, the semiconductor control element 85, the semiconductor light emitting element 86, and the semiconductor control element are used for each substrate such as the LED light emitting block 80 and the dimming signal control unit 54. A configuration in which a circuit element such as a TR is provided is shown. However, the present invention is not limited to this configuration, and for example, a plurality of LED light emitting blocks 80 and circuit elements provided in the dimming signal control unit 54 may be provided on one substrate, or a plurality of LEDs may emit light. The circuit element provided in the block 80 may be provided on one substrate.

Although the preferred embodiment of the present invention has been described above, the control circuit for the lighting device according to the present invention is not limited to the above-described embodiment, and various modifications are made within the scope of the present invention. Needless to say, is possible.

A to D: control circuit for lighting device, H, I, K: current path,
1: DC power supply, 2-12: current path, 21: current path, 22: current path,
LEDs 1-16: semiconductor light emitting element, FET 1-6: semiconductor control element,
D1-5: semiconductor rectifying element, R1-12: resistance element,
TR: Semiconductor control element,
ZD1-7: Semiconductor constant voltage element,
50: DC power supply, 51: LED constantly lit part,
52: LED series-parallel conversion unit, 53: LED series-parallel control unit,
54: Dimming signal control unit, 55: Overvoltage absorption unit, 56: Current path,
62: LED on / off control unit, 63: LED on / off control unit,
64: Photoconductive part,
80: LED light emitting block,
81: Photoconductive element, 82: Light emitting element, 83: Light receiving element, 84: Package, 85: Semiconductor control element, 86: Semiconductor light emitting element, 87: Rectifying element, 88: Resistance element

Claims (4)

A comparator that compares the reference voltage with the voltage applied through the negative voltage input section and sucks in an amount of current according to the comparison result.
It is provided with a dimming signal input section that is connected to the negative voltage input section of the comparator and receives dimming signal input from the outside.
A control circuit for a lighting device, characterized by having a dimming signal control unit that performs dimming control by the dimming signal. The control circuit for a lighting device according to claim 1, wherein the comparator is a comparator. A DC power supply that applies a DC voltage and
An LED constantly lit unit equipped with an LED that constantly lights when a voltage is applied from the DC power supply,
An LED series-parallel converter with LEDs that the series-parallel connection converts,
Claim 1 or 2 is characterized by having an LED series-parallel control unit that converts the series-parallel connection of LEDs according to the LED series-parallel conversion unit according to the amount of current sucked into the comparator. The control circuit for the lighting device described in. A DC power supply that applies a DC voltage and
An LED constantly lit unit equipped with an LED that constantly lights when a voltage is applied from the DC power supply,
An LED lighting / extinguishing unit equipped with an LED that turns on or off,
The illumination according to claim 1 or 2, further comprising an LED lighting / extinguishing control unit that controls an LED related to the LED lighting / extinguishing unit according to the amount of current sucked into the comparator. Control circuit for the device.