JP2019057696A - Light emission diode drive device and illumination for plant cultivation using the same - Google Patents

Abstract

To provide illumination light suitable for plant cultivation.MEANS FOR SOLVING THE PROBLEM: A light emission diode drive device 100 comprises: current restriction means 3 for controlling a power supply amount to a first LED part 11 and a second LED part 12; current detection means 4 for detecting a current detection signal based on a current amount flowing on an output line OL to which the first LED part 11 and the second LED part 12 are serially connected; current control means 30 for outputting an operation control signal to control the operation of first power supply control means 21 and the current restriction means 3 in accordance with the current detection signal detected by the current detection means 4; and forced turning-off means 8 for generating a forced turning-off signal to cause the current control means 30 to operate to forcedly turn off the first LED part 11 and the second LED part 12 in a period in which a voltage value of a rectification voltage rectified by a rectifier circuit 2 is lower than a forced turning-off voltage set to be a value higher than a first forward voltage obtained by adding forward voltages of serially connected LED elements configuring the first LED part 11.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a driving device that drives a light emitting diode to light and a lighting for plant cultivation using the same, and more particularly to a light emitting diode driving device that uses an alternating current power source to drive.

  In recent years, in plant cultivation, growing by artificial lighting has been attracting attention because a stable harvesting and growing period can be obtained without being influenced by the weather. Further, as a light source used for the illumination, a light emitting diode (hereinafter also referred to as “LED”) has advantages such as long life, power saving, and low heat generation, and is expected as a main force in the future. LEDs are fast in responsiveness. For example, research is being conducted on a method for reducing power consumption by providing a light extinction period while maintaining the same brightness peak by a PWM driving method. In plant cultivation facilities, since a large amount of lighting lamps are used, not only the price of the LED itself but also a light and inexpensive driving device and lamp are desired.

  For example, a circuit example shown in FIG. 17 is known as an LED drive circuit in which a direct-current driven LED can be driven with an alternating current for general illumination (Patent Document 1). The LED driving circuit 1700 includes a driving device 710, a control unit 730, switches M1, M2, M3 to MN, LEDs LFIX, L1, L2, L3 to LN, and a current source 750. The driving device 10 is connected with four serially connected LEDs L1, L2, L3-LN and a single additional LED LFIX. According to the LED drive circuit 1700, the LED repeats light emission and extinguishing of the peak at a half cycle of the AC power supply cycle.

  However, in the light source for plant cultivation, the characteristic different from normal illumination is calculated | required. For example, it is said that a pulse wave is more suitable for growing plants than a continuous wave. However, in general lighting, a pulse wave causes flickering and is not preferred. Therefore, if the LED driving circuit for general illumination is applied to a plant as it is, illumination light suitable for plant growth cannot always be obtained.

US Patent Application Publication No. 2010/0134018

  This invention is made | formed in view of such a background, One of the objectives provides the light emitting diode drive device which can provide the illumination light suitable for plant cultivation, and the illumination for plant cultivation using the same There is.

  In order to achieve the above object, a light emitting diode driving device according to one aspect of the present invention can be connected to an AC power source, and a rectifier circuit for obtaining a rectified voltage obtained by rectifying the AC voltage of the AC power source, The first LED unit including at least one LED element connected in series with the output side of the rectifier circuit, and the second LED unit including at least one LED element connected in series with the first LED unit A first energization control means for controlling an energization amount to the first LED unit, connected in parallel with the second LED unit and in series with the first LED unit, and the first LED unit And a second LED unit connected in series, a current limiting means for controlling the amount of current supplied to the first LED unit and the second LED unit, and the first LED unit and the second LED unit connected in series. Amount of current flowing on the output line A current detection means for detecting a current detection signal based on the output signal, and an operation control signal for controlling the operation of the first energization control means and the current limiting means according to the current detection signal detected by the current detection means; And the voltage value of the rectified voltage rectified by the rectifier circuit is higher than the first forward voltage obtained by adding the forward voltage of the LED elements connected in series constituting the first LED unit. A forced turn-off means for generating a forced turn-off signal that operates the current control means to forcibly turn off the first LED part and the second LED part in a period lower than the forced turn-off voltage value set to a value; Can be provided.

  With the above configuration, the rectified voltage exceeds the first forward voltage that can be turned on, and it is possible to forcibly turn off the light regardless of the period during which the light can be turned on. As a result, it is possible to realize a light source suitable for a specific application, such as plant growth.

It is a circuit diagram which shows the LED drive circuit which can be driven with the alternating current power supply which concerns on a comparative example. 2A is a waveform showing the time change of the rectified voltage of the LED drive circuit according to FIG. 1, FIG. 2B is a waveform showing the time change of the light amount using the multistage circuit, and FIG. 2C is a case where the turn-off period is extended in the multistage circuit. It is a graph which shows the waveform which shows the time change of the light quantity of each, respectively. It is a graph which shows the result of having performed plant cultivation by direct current drive illumination and alternating current drive illumination. It is a graph which shows the result of having performed plant cultivation with the illumination which provided the 1 msec light extinction period by direct current drive illumination, the AC drive, and the illumination which provided the 4 msec light extinction period by the AC drive PWM control. It is a block diagram which shows the light emitting diode drive device which concerns on Embodiment 1 of this invention. It is a block diagram which shows the light emitting diode drive device which concerns on Embodiment 2 of this invention. It is a block diagram which shows the light emitting diode drive device which concerns on Embodiment 3 of this invention. It is a block diagram which shows the light emitting diode drive device which concerns on Embodiment 4 of this invention. It is a block diagram which shows the light emitting diode drive device which concerns on Embodiment 5 of this invention. FIG. 10A is a graph showing a temporal change in the light amount of the LED unit by the light emitting diode driving device according to the comparative example, and FIG. 10B is a graph showing a temporal change in the light amount of the LED unit by the light emitting diode driving device according to Embodiment 6. 1 is a circuit diagram illustrating a light emitting diode driving apparatus according to Embodiment 1. FIG. It is a graph which shows the waveform which shows the time change of the input alternating voltage of the LED drive circuit which concerns on the comparative example of FIG. 1, and the electric power of a 1st LED part. It is a graph which shows the waveform which shows the time change of the electric power of the 1st LED part at the time of setting the input alternating voltage of the light emitting diode drive device of FIG. 11, and the light extinction period to _TOFF1 . It is a graph which shows the waveform which shows the time change of the electric power of the 1st LED part at the time of setting the input alternating voltage of the light emitting diode drive device of FIG. 11, and the light extinction period to _TOFF2 . It is a graph which shows the waveform which shows the time change of the electric power of the 1st LED part when the input alternating voltage of the light emitting diode drive device of FIG. 11 and a light extinction period are set to _TOFF3 . 6 is a circuit diagram illustrating a light emitting diode driving apparatus according to Embodiment 2. FIG. It is a circuit diagram which shows the LED drive circuit which can be driven with the conventional alternating current power supply.

  According to the light emitting diode driving apparatus according to an embodiment of the present invention, in addition to the above-described configuration, the forced turn-off voltage value is further connected to the LED elements connected in series constituting the first LED portion and the second LED portion. The forward voltage can be set to a value lower than the second forward voltage.

  Moreover, according to the light emitting diode drive device which concerns on other embodiment of this invention, in addition to any one of the said structures, the said forced extinction voltage value of the said forced extinction means can be made variable. With the above configuration, it is possible to change the extinguishing period forcibly extinguishing, and fine adjustment according to the application is possible.

  Furthermore, according to the light emitting diode driving device according to another embodiment of the present invention, in addition to any of the above-described configurations, in order to generate a harmonic suppression voltage based on the rectified voltage output from the rectifier circuit. The harmonic suppression voltage generating means, and the current control means compares the current detection signal detected by the current detection means with the harmonic suppression voltage generated by the harmonic suppression voltage generating means, The first energization control means and the current limiting means can be controlled to suppress harmonic components. With the above configuration, it is possible to control the output waveform by comparing the harmonic component on the input side with the LED drive current actually obtained, and effective suppression of the harmonic component can be realized.

  Furthermore, according to a light emitting diode driving apparatus according to another embodiment of the present invention, in addition to any of the above-described configurations, the current control means includes a forced turn-off signal generated by the forced turn-off means, and The harmonic suppression voltage generated by the harmonic suppression voltage generation means can be invalidated. With the above configuration, the LED can be easily and forcibly turned off by invalidating the harmonic suppression voltage in a section where the rectified voltage is lower than the forced turn-off voltage value.

  Furthermore, according to the light emitting diode driving device according to another embodiment of the present invention, in addition to any of the above configurations, the current control unit includes an operational amplifier, and the forced turn-off is provided on one input side of the operational amplifier. The forced extinction signal generated by the means and the harmonic suppression voltage generated by the harmonic suppression voltage generation means can be input. With the above configuration, by applying a forced turn-off signal and a harmonic suppression voltage to one input of the operational amplifier, the LED is easily forcibly turned off by disabling the harmonic suppression voltage in the section where the forced turn-off signal acts. It becomes possible.

  Furthermore, according to a light emitting diode driving apparatus according to another embodiment of the present invention, in addition to any of the above-described configurations, the current control unit uses the rectified voltage rectified by the rectifier circuit as a reference voltage, and An operation control signal for controlling the operations of the first energization control unit and the current limiting unit is output, the fluctuation of the rectified voltage detected by the harmonic suppression voltage generation unit, the current detection signal detected by the current detection unit, Based on the sum, the current control means can be configured to control the operations of the first energization control means and the current limiting means.

  Furthermore, according to the light emitting diode driving device according to another embodiment of the present invention, in addition to any of the above-described configurations, the first LED unit and the first LED unit connected in series with the second LED unit. LED driving means for bypassing the current supplied to the current limiting means for controlling the current supply to the two LED units, and connecting the current limiting means in parallel with the LED driving means it can.

  Furthermore, according to the light emitting diode driving device according to another embodiment of the present invention, in addition to any of the above-described configurations, the downstream side of the first energization control unit is provided between the current detection unit and the current limiting unit. Can be connected to.

  Furthermore, according to the light emitting diode driving device according to another embodiment of the present invention, in addition to any of the above-described configurations, in order to further adjust the peak illuminance of light emitted from the first LED unit and the second LED unit. The peak illuminance adjusting means having the variable resistor can be provided. With the above configuration, not only control of the extinguishing period but also adjustment of the peak illuminance, that is, the amplitude side can be performed, so that it is possible to perform light control while maintaining the extinguishing period.

  Furthermore, according to the light emitting diode driving device according to another embodiment of the present invention, in addition to any one of the above-described configurations, at least one of the first LED unit and the second LED unit connected in series. A third LED part including an LED element, connected to the first LED part and the second LED part in parallel with the third LED part and in series with the first LED part and the second LED part. Second energization control means for controlling the energization amount, wherein the current control means is configured to control the first energization control means and the second energization control according to a current detection signal detected by the current detection means. An operation control signal for controlling the operation of the means and the current limiting means can be output.

  Furthermore, according to the light emitting diode driving device according to another embodiment of the present invention, in addition to any of the above-described configurations, the first LED unit, the second LED unit, and the third LED unit are further connected in series. A fourth LED part including at least one LED element; and the fourth LED part connected in parallel with the fourth LED part and in series with the first LED part, the second LED part, and the third LED part. And a third energization control means for controlling the energization amount to one LED section, the second LED section and the third LED section, and the current control means detects the current detected by the current detection means. An operation control signal for controlling operations of the first energization control means, the second energization control means, the third energization control means, and the current limiting means can be output in response to the signal.

  Furthermore, according to the light emitting diode driving device according to another embodiment of the present invention, in addition to any of the above-described configurations, the forced turn-off voltage value is further output to an external device, and the forced light from the external device is output. Communication means for receiving an evaluation signal indicating an evaluation value with respect to the turn-off voltage value, wherein the forced turn-off means can adjust the forced turn-off voltage value based on an evaluation signal from an external device received by the communication means. Can be configured. With the above configuration, the forced turn-off voltage value can be adjusted based on the evaluation value of the external device, and the length of the turn-off period can be finely adjusted to a more appropriate value according to the application.

  Furthermore, according to the plant cultivation illumination according to another embodiment of the present invention, any one of the light emitting diode driving devices described above can be used.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a light emitting diode driving device for embodying the technical idea of the present invention and lighting for plant cultivation using the same, and the present invention is a light emitting diode driving device and The plant cultivation lighting using this is not specified as follows. Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments.

  Hereinafter, an example in which the light emitting diode driving device is used as illumination for plant cultivation will be described. Conventionally, an illuminating device using a sine wave multistage drive circuit that rectifies a sine wave AC voltage and applies and illuminates the LED units connected in multiple stages has been proposed. Here, as a comparative example, an example of a sinusoidal multistage drive circuit is shown in FIG. In such a sinusoidal multistage drive circuit, the full-wave rectified rectified voltage periodically changes with time as shown in FIG. 2A, but the LED unit is not more than the forward voltage determined by the number of LED elements connected in series. Since it does not light up, it is turned off in the section where the rectified voltage is low. As a result, as shown in FIG. 2B, the peak light emission and extinction are repeated at a half cycle of the AC power supply cycle, and thus flickering occurs. As general illumination light, an operation that can obtain uniform light with little flickering is required, and thus a mechanism that shortens the turn-off period is required. For example, measures are taken such as smoothing the rectified voltage subjected to full-wave rectification so that it does not drop below the forward voltage.

  On the other hand, plant factories that artificially cultivate plants have become popular in recent years. As a light source for plant growth used in such a plant factory, LEDs with low power consumption and long life are used. Conventionally, irradiation was performed by direct current drive. However, according to a test conducted by the present inventors, a pulse-like state in which peak light emission and extinction are repeated by an alternating current power source with an average illuminance equal to that of a direct current drive LED. Illuminating the lighting pattern, and comparing the growth status of three types of plants, spinach (plant A), wasabi (plant B), and turnip (plant C), as shown in the graph of FIG. The knowledge that the effective quantum yield is higher was obtained. In addition, the vertical axis | shaft of the graph of FIG. 3, FIG. 4 shows the effective quantum yield (phi) II (effective quantum yield) using chlorophyll fluorescence. This is a numerical value of how much light is consumed for photosynthesis, with 1 being the maximum value. In addition, the range of the maximum value and the minimum value is added above each bar of the graph.

In general, in plant cultivation, attention is focused on increasing the peak illuminance of illumination light. In order to increase the peak illuminance, it is conceivable to increase the drive current. However, the power consumption is increased by that amount. Measures that take this into account are also required. Here, the present inventors pay attention to the turn-off period of the turn-on period, and lengthen the turn-off time with respect to the turnip (plant C) in order to examine in detail the effect of changes in the turn-off time on plant growth. A test was conducted. Here, in the case of pulse lighting using an AC power source, the case where the LED is lit with a commercial power source of 60 Hz and 100 V AC, with the LEDs being equally divided into four stages and connected in series with the forward voltage V _{f_all} as a whole of about 120 V. Considering this, one cycle obtained by full-wave rectifying one cycle of the AC power supply 1/60 s≈16 ms is 8 ms, of which about 7 ms is turned on, and about 1 ms is turned off. On the other hand, a test was conducted with a lighting pattern (corresponding to FIG. 2C) adjusted so that the extinguishing period was increased to 4 ms, which is four times as long (lighting period 4 ms). The result is shown in the graph of FIG. For comparison, the graph also includes DC drive data. As is apparent from this graph, by extending the extinguishing period from the state of FIG. 2B as shown in FIG. 2C, it is common knowledge that the effective quantum amount of the plant is expected to decrease as the integrated value of the light amount decreases. However, conversely, the effective quantum yield was found to be high. In addition, it is preferable to lengthen the turn-off period from the viewpoint of the heat generation amount and power consumption of the LED.

  Thus, according to the tests conducted by the present inventors, the length of this extinction period affects the effective quantum yield related to plant photosynthesis. Therefore, the knowledge that it influences the growth of the plant was obtained. During this extinction period, it seems that the optimal time changes depending on the variety of plant and the illuminance of the peak. Therefore, in this embodiment, a light source suitable for plant cultivation is provided by adding a function capable of adjusting the extinction period to the LED driving device based on the above knowledge. Specifically, by adding a forced light extinction circuit, the length of the light extinction period can be adjusted according to the type of plant to be grown or even in the environment such as the growing season and average temperature even for the same type of plant. By making it possible to adjust accordingly, it becomes possible to supply more appropriate light to the plant.

There are the following two methods for adjusting the extinction period in an AC-driven multistage circuit.
1. Adjust the lighting start timing. For example, the overall forward voltage Vf of the LED is adjusted to set the lighting start voltage.
2. Adjust the timing to start turning off. For example, an AC voltage is detected, and the light is lit only for a period that is equal to or higher than a set voltage.

Among these, according to the former method, since Vf of each LED cannot be adjusted, the number of LEDs connected in series is adjusted, and the circuit becomes complicated. Also, when the number of LEDs used changes, the illuminance also changes, which is a constraint for obtaining a desired design value. Therefore, in this embodiment, the latter method is adopted. Specifically, a method is employed in which a rectified voltage obtained by rectifying the AC voltage is detected, and the light is lit only for a period longer than the set voltage.
(Embodiment 1)

FIG. 5 shows a circuit diagram of the light-emitting diode driving apparatus 100 according to Embodiment 1 of the present invention. The LED driving apparatus 100 shown in this figure includes a rectifier circuit 2, an LED assembly 10, first energization control means 21, current limiting means 3, current detection means 4, current control means 30, and forced extinction. Means 8 are provided. The light emitting diode driving device 100 is connected to an AC power supply AP and obtains a rectified voltage obtained by rectifying an AC voltage by the rectifier circuit 2. Further, on the output side of the rectifier circuit 2, the LED assembly 10 composed of the first LED unit 11 and the second LED unit 12 is connected in series on the output line OL. The LED assembly 10, the current limiting means 3, and the current detection means 4 are connected in series to the output line OL.
(Rectifier circuit 2)

The rectifier circuit 2 is connected to an AC power supply AP. The rectifier circuit 2 is a member for obtaining a rectified voltage by full-wave rectifying the AC voltage supplied from the AC power supply AP. The rectifier circuit 2 is preferably a diode bridge. A rectified voltage obtained by rectifying the AC voltage is obtained by passing through the rectifying circuit 2 constituted by a diode bridge and rectifying. In a general lighting device, a smoothing capacitor or the like is used as a smoothing means for smoothing the rectified voltage in order to reduce flicker. In addition, in plant cultivation lighting, since it is not required to reduce flickering as in general lighting, such a smoothing capacitor may not be used. In particular, an electrolytic capacitor generally used as a smoothing capacitor has a large capacity, but has a long life due to deterioration with the passage of time due to a decrease in electrolytic solution. Therefore, by eliminating the electrolytic capacitor from the light emitting diode driving device, it is possible to avoid a situation in which the life of the light emitting diode driving device is determined by the life of the electrolytic capacitor, and the reliability that can be used stably over a long period of time. A highly light-emitting diode driving device is realized.
(LED assembly 10)

  The LED assembly 10 includes a first LED unit 11 and a second LED unit 12. The first LED unit 11 is connected in series with the output side of the rectifier circuit 2. The second LED unit 12 is connected in series with the first LED unit 11. Each LED unit such as the first LED unit 11 and the second LED unit 12 connects one or more LED elements in series and / or in parallel. As the LED element, a surface mount type (SMD) or a bullet type LED can be used as appropriate. Moreover, the package of the SMD type LED element can select the outer shape according to the application, and a rectangular type in a plan view can be used. Furthermore, it goes without saying that an LED in which a plurality of LED elements are connected in series and / or in parallel in a common package can be used as the LED unit.

  Moreover, the 1st LED part 11 can also be divided | segmented into a some 1st LED division part. For example, the first LED unit 11 is divided into two parts: a first LED dividing unit and a second LED dividing unit. The 1st LED division part and the 2nd LED division part are mutually connected in series. In addition, you may connect the 2nd LED part 12 between a 1st LED division part and a 2nd LED division part. By doing in this way, the 1st LED part 11 lighted for a long time can be disperse | distributed, and the light distribution of the LED aggregate | assembly 10 can be closely approached. In particular, the first LED unit 11 that is lit for a long time has a larger amount of heat generation because the driving time is longer than that of the second LED unit 12 that blinks. For this reason, it becomes advantageous also in terms of heat dissipation by dividing and arranging the first LED unit 11 having a large calorific value.

The first forward voltage V _f1 that is an added value of the forward voltages of the LED elements included in the first LED unit 11 is determined by the number of LED elements connected in series. For example, the first forward voltage when 10 LED elements having a forward voltage of 3.6V are used is 3.6 × 10 = 36.0V. The second forward voltage V _f2 for lighting both the first LED part 11 and the second LED part 12 is further connected in series to the first forward voltage V _f1 and included in the second LED part 12. A value obtained by adding a forward voltage of the LED element.
(First energization control means 21)

  The first energization control means 21 is a member for controlling the energization amount to the first LED unit 11. The first energization control unit 21 is connected in parallel with the second LED unit 12 and in series with the first LED unit 11. The first energization control means 21 has one end connected in series with the downstream side of the first LED unit 11 and the other end connected to the upstream side of the current limiting means 3. The first energization control means 21 constitutes a bypass path that adjusts the energization amount to the first LED unit 11. That is, since the amount of current bypassed by the first energization control means 21 can be adjusted, the energization amount of the first LED unit 11 can be controlled as a result. In the example of FIG. 5, the first energization control means 21 is connected in parallel with the second LED unit 12 to form the first bypass path BP1. The parallel connection here does not require that both ends of each LED unit and each energization control means are connected, and one end of each energization control unit is connected to one end of each LED unit, It is sufficient if it is configured to be branched. For example, in the example of FIG. 5, the first energization control unit 21 has one end connected to the upstream side of the second LED unit 12 and the other end connected to the upstream side of the current limiting unit 3 on the output line OL. . As described above, the parallel connection of the energization control means is used to indicate a connection form in which the current of each LED unit connected on the output line OL is branched.

The 1st electricity supply control means 21 can be comprised by the bypass means which bypasses the electric current which flows through the 1st LED part 11, for example, and the current control means 30 which controls operation | movement of this bypass means. The energization control means is a member for controlling a current circuit that performs current driving of the LED unit. For example, the first energization control unit 21 and the current limiting unit 3 that controls the operation of the first energization control unit 21, that is, the operation such as ON / OFF and continuously variable current amount, form a kind of constant current circuit. . The constant current circuit is controlled by, for example, monitoring the current amount of the LED assembly 10 using the current detection means 4 connected to the output line OL, and the current control means 30 determines the control amount of the bypass means based on this value. Switch. In addition, the first energization control means 21 may be configured integrally with the first energization control means in addition to the bypass means and the current control means 30 as described above. Such first energization control means 21 can be composed of a semiconductor drive element such as a transistor.
(Current limiting means 3)

The current limiting unit 3 is a member that is connected in series with the first LED unit 11 and the second LED unit 12 and controls the amount of current supplied to the first LED unit 11 and the second LED unit 12.
(Current detection means 4)

The current detection means 4 is a member for detecting a current detection signal based on the amount of current flowing on the output line OL to which the first LED unit 11 and the second LED unit 12 are connected in series. The light emitting diode driving device 100 controls the energization amount for each LED unit based on the current value detected by the current detecting means 4. In other words, current control is based on the amount of current that is actually energized rather than the voltage value of the rectified voltage, so it is not affected by variations in the forward voltage of the LED element, and the LED unit can be accurately switched at an appropriate timing. Is realized and stable operation with high reliability is expected. This current value is detected by the current detection means 4. A resistor or the like can be suitably used for the current detection means 4. In the example of FIG. 5, the current detection unit 4 is connected to the downstream side of the current limiting unit 3. However, the current detection unit 4 is not limited to this position, and may be provided at any position on the output line OL. Furthermore, the current detection means 4 is not limited to one, and a plurality of current detection means 4 may be provided.
(Current control means 30)

The current control unit 30 is a member for outputting an operation control signal for controlling operations of the first energization control unit 21 and the current limiting unit 3 in accordance with the current detection signal detected by the current detection unit 4. The current control means 30 outputs an operation control signal for controlling the operations of the first energization control means 21 and the current limiting means 3 using the rectified voltage rectified by the rectifier circuit 2 as a reference voltage. The downstream side of the first energization control means 21 is connected between the current detection means 4 and the current limiting means 3.
(Forced extinguishing means 8)

The forced extinguishing means 8 sets the compulsory extinguishing voltage value _Voff set so that the voltage value of the rectified voltage rectified by the rectifier circuit 2 is higher than the first forward voltage enabling the first LED unit 11 to be lit. It is a member for generating a forced turn-off signal that operates the current control means 30 so that the first LED unit 11 and the second LED unit 12 are turned off forcibly in the period below. As a result, the rectified voltage exceeds the first forward voltage that can be turned on, and it is possible to forcibly turn off the light regardless of the period during which the light can be turned on. As a result, it is possible to realize a light source suitable for a specific application meaningful in the extinguishing period, for example, plant growth. In particular, by reversely using the extinguishing period that occurs when a DC-driven light-emitting diode is driven with an AC voltage, it becomes possible to effectively use a place where the quality of illumination is low as general illumination. .

In addition, the forced turn-off means 8 can change the forced turn-off voltage value V _off . Thereby, the length of the extinguishing period forcibly extinguishing can be made variable, and fine adjustment according to the application can be made. For example, in plant growth, it is possible to make fine adjustments according to the type of plant to be cultivated, the same plant, the growing environment, the growing place, and individual differences, improving yield and promoting growth, improving resistance to diseases, etc. Figured. In particular, since it is only necessary to add a relatively simple forced extinguishing means 8, a function for adjusting the extinguishing period can be easily and inexpensively added.
(Embodiment 2)

The light emitting diode driving device can also include harmonic suppression voltage generating means 6. In order to make the light emitting diode driving device conform to the harmonic current standard, it is desired to design the sine wave current waveform in the same manner as the incandescent lamp. Therefore, by superimposing a sine wave on the reference voltage of the current limiting means 3, the LED driving current waveform is approximated to a sine wave, and an inexpensive and compact light emitting diode driving device adapted to the harmonic current standard exceeding 25W. Can provide. Such an example is shown in FIG. 6 as a light emitting diode driving apparatus 200 according to the second embodiment. In addition to the configuration of the first embodiment, the light emitting diode driving device 200 shown in this figure further includes harmonic suppression voltage generation means 6.
(Harmonic suppression voltage generating means 6)

  The current control unit 30 is connected to the harmonic suppression voltage generation unit 6. The harmonic suppression voltage generator 6 generates a harmonic suppression voltage based on the rectified voltage output from the rectifier circuit 2. Here, the harmonic suppression voltage generation means 6 compresses the rectified voltage rectified by the rectifier circuit 2 to an appropriate magnitude and sends it to the current control means 30. The current control means 30 uses the signal sent from the harmonic suppression voltage generation means 6 as a reference signal and compares it with the current detection signal detected by the current detection means 4. Based on the comparison result, the current control unit 30 drives each LED unit at an appropriate timing and current via each of the first energization control unit 21 to the fourth energization control unit 24. Thereby, the control which adjusts an output waveform is attained by contrast with the harmonic component of an input side, and the LED drive current actually obtained, and suppression of an effective harmonic component is realizable.

Further, the current control unit 30 invalidates the harmonic suppression voltage generated by the harmonic suppression voltage generation unit 6 with the forced extinction signal generated by the forced extinction unit 8. Thereby, it becomes easy to forcibly turn off the LED assembly 10 by invalidating the harmonic suppression voltage in a section where the rectified voltage is lower than the forced turn-off voltage value V _off . In particular, the forced extinguishing means 8 can be configured by using a part of the circuit included in the harmonic suppression voltage generating means 6, for example, a rectified voltage dividing circuit of the rectified voltage, so that the circuit configuration of the forced extinguishing means 8 is simplified. In addition, by sharing some circuits, it is possible to reduce the number of parts in the entire LED driving device, simplify the circuit configuration, reduce costs, and the like.
(Operation example of Embodiment 1)

Next, an operation example of the light emitting diode driving apparatus 100 according to Embodiment 1 shown in FIG. 5 will be described. Here, the forced extinction voltage value V _off is set in advance to a value higher than the first forward voltage V _{f1 obtained} by adding the forward voltages of the LED elements constituting the first LED unit 11 to turn on the first LED unit 11. Set it. You may design so that the 2nd forward voltage _Vf2 for lighting the 1st LED part 11 and the 2nd LED part 12 may become a value higher than the forced light extinction voltage value _Voff .

The rectified voltage gradually rises from 0 V, becomes higher than the first forward voltage V _f1 , and the rectified voltage reaches the forced turn-off voltage value V _off even when the first LED unit is turned on. Until then, the first LED unit 11 (and the second LED unit 12 together) is turned off. Specifically, the forcible turn-off means 8 controls the current control means 30 not to turn on the first energization control means 21 and the current limiting means 3 so that the first LED section 11 and the second LED section 12 are not turned on. ing.

Next, when the rectified voltage exceeds the forced turn-off voltage value V _off , the restriction by the forced turn-off means 8 is released, and the first LED unit 11 is turned on. In a section where the rectified voltage is lower than the second forward voltage V _f2 , the first LED unit 11 is controlled to be energized by the first energization control means 21. At this time, only the first LED unit 11 is turned on and the second LED unit 12 is turned off.

When the rectified voltage further increases and reaches the second forward voltage V _f2 , energization to the second LED unit 12 is started. In a section where the rectified voltage is equal to or higher than the second forward voltage V _f2 , both the first LED unit 11 and the second LED unit 12 are turned on, and the current limiting unit 3 controls the energization of the second LED unit 12.

On the other hand, when the rectified voltage starts to decrease beyond the peak, when the second forward voltage V _f2 is reached, the energization of the second LED unit 12 is stopped and the light is turned off. In a section where the rectified voltage is equal to or lower than the second forward voltage V _f2 , the second LED unit 12 is turned off, and only the first LED unit 11 is turned on by the first energization control unit 21.

When the forced turn-off voltage value V _off is reached, forced turn-off control by the forced turn-off means 8 is started, and both the first LED unit 11 and the second LED unit 12 are turned off.

When the rectified voltage reaches 0V and then starts to rise again, the forced turn-off control by the forced turn-off means 8 is maintained until the rectified voltage reaches the forced turn-off voltage value V _off , and the first LED unit 11 and the second LED. When both units 12 are turned off and the forced turn-off voltage value V _off is reached, the lighting of the first LED unit 11 is shared as described above, and the same operation is repeated.
(Embodiment 3)

  In the example of FIG. 5 described above, the circuit configuration example in which the two LED units constituting the LED assembly 10 are used and the first LED unit 11 and the second LED unit 12 are connected in series has been described. However, the present invention does not limit the number of LED sections to two, but can be three or more. Such an example will be described with reference to FIGS. In these drawings, the same members as those in FIG. 5 are denoted by the same reference numerals and detailed description thereof is omitted as appropriate.

  The light emitting diode driving device 300 according to the third embodiment shown in FIG. 7 further includes a third LED unit 13 and second energization control means 22. The third LED unit 13 is connected in series with the first LED unit 11 and the second LED unit 12. The third LED unit 13 also includes at least one LED element, like the first LED unit 11 and the second LED unit 12.

The second energization control means 22 is a member for controlling the energization amount to the first LED unit 11 and the second LED unit 12. The third LED unit 13 is connected in parallel and in series with the first LED unit 11 and the second LED unit 12. The current control unit 30 outputs an operation control signal for controlling the operations of the first energization control unit 21, the second energization control unit 22, and the current limiting unit 3 in accordance with the current detection signal detected by the current detection unit 4. It is configured as follows.
(Embodiment 4)

In addition to the third LED unit 13 and the second energization control unit 22, the light emitting diode driving device 400 according to Embodiment 4 shown in FIG. 8 further includes a fourth LED unit 14 and a third energization control unit 23. The fourth LED unit 14 is also connected in series with the first LED unit 11, the second LED unit 12, and the third LED unit 13. The fourth LED unit 14 also includes at least one LED element, like the first LED unit 11 and the like. The first LED unit 11 to the fourth LED unit 14 are preferably the same number of LED elements. However, as described above, the forced turn-off voltage value V _off is preferably set to V _f1 <V _off and further V _f1 <V _f2. The number of LED elements may be adjusted as appropriate between the second LED unit 12 and different numbers.

  The third energization control unit 23 is connected in parallel with the fourth LED unit 14 and in series with the first LED unit 11, the second LED unit 12, and the third LED unit 13. The third energization control unit 23 controls the energization amount to the first LED unit 11, the second LED unit 12, and the third LED unit 13. The current control unit 30 controls the operations of the first energization control unit 21, the second energization control unit 22, the third energization control unit 23, and the current limiting unit 3 in accordance with the current detection signal detected by the current detection unit 4. The operation control signal is configured to be output.

The second LED unit 12, the third LED unit 13, and the fourth LED unit 14 each have a first energization control unit 21, a second energization control unit 22, and a third energization control unit for controlling the energization amount at one end. 23 is connected. The first energization control means 21, the second energization control means 22, and the third energization control means 23 are each provided in parallel with the LED unit, and the other end is connected to the upstream side of the current detection means 4, A bypass path for adjusting the energization amount to the LED unit is configured. That is, since the amount of current bypassed by the first energization control unit 21, the second energization control unit 22, and the third energization control unit 23 can be adjusted, the energization amount of each LED unit can be controlled as a result. In the example of FIG. 8, the 1st electricity supply control means 21 is connected in parallel with the 2nd LED part 12, and 1st bypass path BP1 is formed. Moreover, the 2nd electricity supply control means 22 is connected in parallel with the 3rd LED part 13, and forms 2nd bypass path BP2. Further, the third energization control means 23 is connected in parallel with the fourth LED portion 14 to form a third bypass path BP3.
(Current control circuit)

  In addition, a current control circuit is provided for controlling a current circuit that performs current driving of the LED portion. In the circuit example of FIG. 8, the first energization control means 21, the second energization control means 22, the third energization control means 23, the fourth energization control means 24, the current control means 30, and the current control signal applying means 5 A kind of constant current circuit is configured, and this current circuit is controlled by the current control means 30 and the current control signal applying means 5.

  The current control means 30 is connected to the first energization control means 21, the second energization control means 22, the third energization control means 23, and the fourth energization control means 24 via the current control signal applying means 5. The current control means 30 controls operations such as ON / OFF of the first energization control means 21, the second energization control means 22, the third energization control means 23, and the fourth energization control means 24, and continuously varying the amount of current. The current control means 30 is connected to the current detection means 4 and monitors the current amount of the LED assembly 10, and based on the value, the first energization control means 21, the second energization control means 22, and the third energization control means 23. The control amount of the fourth energization control means 24 is switched.

  In the example of FIG. 8, the current control unit 30 controls the energization limit amount to the first LED unit 11 by the first energization control unit 21 based on the energization amount of the first LED unit 11. Specifically, the first energization control means 21, the second energization control means 22, the third energization control means 23, and the fourth energization control means 24 are in an ON state, and the first energization control means 21 is determined according to the energization amount. Drives the first LED unit 11 with current. Thereafter, when the input voltage rises and reaches a voltage that can drive both the first LED unit 11 and the second LED unit 12, current starts to flow through the second LED unit 12, and when the current value exceeds a certain amount, The first energization control means 21 is turned off. Furthermore, the current control unit 30 controls the energization limit amount to the first LED unit 11 and the second LED unit 12 by the second energization control unit 22 based on the energization amounts of the first LED unit 11 and the second LED unit 12. . Specifically, the second energization control unit 22 drives the first LED unit 11 and the second LED unit 12 in accordance with the energization amount. Thereafter, when the input voltage rises and reaches a voltage that can drive the first LED unit 11, the second LED unit 12, and the third LED unit 13, a current starts to flow through the third LED unit 13. Exceeds a certain amount, the second energization control means 22 is turned off.

  Furthermore, the current control means 30 is based on the energization amounts of the first LED part 11, the second LED part 12, and the third LED part 13, and the first LED part 11, the second LED part 12, The energization limit amount to the three LED units 13 is controlled. Specifically, the third energization control unit 23 drives the first LED unit 11, the second LED unit 12, and the third LED unit 13 in accordance with the energization amount. Thereafter, when the input voltage rises and reaches a voltage that can drive the first LED unit 11, the second LED unit 12, the third LED unit 13, and the fourth LED unit 14, current starts to flow through the fourth LED unit 14. If the current value exceeds a certain amount, the third energization control means 23 is turned off. Finally, the fourth energization control unit 24 and the current control unit 30 drive the first LED unit 11, the second LED unit 12, the third LED unit 13, and the fourth LED unit 14 in accordance with the energization amount.

  As described above, the LED driving device 400 uses the AC power supply AP such as a household power supply, and the LED elements arranged in series according to the periodically changing pulsating voltage obtained after rectifying the AC. A plurality of bypass circuits configured to light up an appropriate number of each are provided, and the current control means 30 can be operated so that each bypass circuit operates appropriately.

  The light emitting diode driving device 400 sequentially energizes the first LED unit 11, the second LED unit 12, the third LED unit 13, and the fourth LED unit 14 as the current value increases. In particular, by restricting the energization amount to each LED unit by current control, the energization amount of the LED unit can be controlled according to the current amount, and the LED can be driven to be driven efficiently with respect to the pulsating voltage.

Further, in the example of FIG. 8, the LED driving means 3 ′ is connected in parallel with the fourth energization control means 24, and a part of the current flowing through the fourth energization control means 24 is branched by the LED driving means 3 ′. The LED driving means 3 ′ reduces the load on the fourth energization control means 24.
(Embodiment 5)
(Communication means 9)

Furthermore, the light emitting diode driving device may be provided with a communication means 9. Such an example is shown in FIG. 9 as a light emitting diode driving apparatus 500 according to the fifth embodiment. The communication means 9 outputs a forced turn-off voltage value V _off to an external device and receives an evaluation signal indicating an evaluation value for the forced turn-off voltage value V _off from the external device. The forced turn-off means 8 adjusts the forced turn-off voltage value V _off based on the evaluation signal from the external device received by the communication means 9. As a result, the forced extinction voltage value V _off can be adjusted based on the evaluation value of the external device, and the length of the extinction period can be finely adjusted to a more appropriate value according to the application.
(Embodiment 6)
(Light intensity pattern adjustment)

Moreover, according to the light emitting diode drive device which concerns on Embodiment 6 of this invention, the pattern in which the light quantity of a LED part changes with time can also be adjusted. As shown in FIG. 10A, the light quantity of the LED unit by the light emitting diode driving apparatus 1000 according to the comparative example was designed so that the light quantity increases sharply when switching from the OFF state to the ON state. On the other hand, in the light emitting diode driving device according to Embodiment 6, as shown in FIG. 10B, the rising light amount sharply increased to an initial value lower than the maximum light amount, and then reached the maximum light amount in a curved shape or an arc shape. After that, it was designed so that the light intensity gradually decreased to the same light amount as the initial value with a similar curve, and then suddenly turned off. As a result of performing comparative tests using these light sources as light sources for plant growth by the present inventors, plants tend not to become diseased (especially chipburn) by adopting a light quantity pattern as shown in FIG. 10B. It has been found. Although the mechanism is not clear, even in the lighting pattern that repeatedly turns on and off, switching the lighting and turning off is not a steep change, but the light quantity change is made gentle, thereby reducing the load and increasing the immunity of the plant It is assumed that it contributes to
<Example 1>

Next, an example of a specific circuit configuration of the light-emitting diode driving apparatus 400 according to the fourth embodiment is shown as a first example in the circuit diagram of FIG. The light emitting diode driving device 400 ′ shown in this figure uses a diode bridge as the rectifier circuit 2 connected to the AC power supply AP. A fuse FS for preventing overcurrent is provided between the AC power supply AP and the rectifier circuit 2. Further, a bypass capacitor BC is connected to the output side of the rectifier circuit 2. Although not shown, a protective resistor or a surge protection circuit may be provided between the AC power supply AP and the rectifier circuit 2.
(AC power supply AP)

As the AC power supply AP, a commercial power supply of 100V or 200V can be suitably used. 100V or 200V of the commercial power supply is an effective value, and the maximum voltage of the rectified rectified waveform is about 141V or 282V.
(LED assembly 10)

  The LED units constituting the LED assembly 10 are connected in series with each other, divided into a plurality of blocks, and a terminal is drawn out from the boundary between the blocks, and the first energization control unit 21 and the second energization control unit 22. The third energization control means 23 and the fourth energization control means 24 are connected. In the example of FIG. 11, the LED assembly 10 is configured by four groups of a first LED unit 11, a second LED unit 12, a third LED unit 13, and a fourth LED unit 14.

Each LED part 11-14 shown in FIG. 11 represents the LED package 1 in which one LED symbol mounts a plurality of LED chips. In this example, each LED package 1 has 10 LED chips mounted thereon. The number of light emitting diodes connected to each LED unit or the number of LED units connected is determined by the added value of forward voltages, that is, the total number of LED elements connected in series and the power supply voltage to be used. For example, when a commercial power source is used, the total forward voltage V _fall that is the sum of V _f of each LED unit is set to about 141 V or less.

  The LED unit includes one or more arbitrary numbers of LED elements. As the LED element, one LED chip or a plurality of LED chips combined in one package can be used. In this example, an LED package 1 including 10 LED chips is used as one LED element shown in the figure.

In the example of FIG. 11, the four LED units are designed to have the same V _f . However, the present invention is not limited to this example, and as described above, the number of LED units may be 3 or less, or 5 or more. By increasing the number of LED units, it is possible to increase the number of current controls and perform more detailed lighting switching control between the LED units. Furthermore, the V _{f of} each LED unit may not be the same.
(First energization control means 21 to fourth energization control means 24)

  The 1st electricity supply control means 21, the 2nd electricity supply control means 22, the 3rd electricity supply control means 23, and the 4th electricity supply control means 24 are members for carrying out an electric current corresponding to each LED part. Such first energization control means 21 to fourth energization control means 24 are constituted by switching elements such as transistors. In particular, FETs are preferable because the saturation voltage between the source and the drain is almost zero, and the amount of current supplied to the LED portion is not hindered. However, it goes without saying that the first energization control means 21 to the fourth energization control means 24 are not limited to FETs, and can be constituted by bipolar transistors or the like.

In the example of FIG. 11, LED current control transistors are used as the first energization control means 21 to the fourth energization control means 24. Specifically, the second LED unit 12, the third LED unit 13, the fourth LED unit 14, and the LED driving unit 3 ′ are the first LED that is the first energization control unit 21 to the fourth energization control unit 24, respectively. The current control transistor 21B, the second LED current control transistor 22B, and the third LED current control transistor 23B are connected. Each LED current control transistor is switched between ON state and current control in accordance with the current amount of the LED section in the previous stage. When the LED current control transistor is turned off, no current flows through the bypass path, and the LED portion is energized. That is, since the amount of current bypassed by each of the first energization control means 21 to the fourth energization control means 24 can be adjusted, the energization amount of each LED unit can be controlled as a result. In the example of FIG. 11, the 1st electricity supply control means 21 is connected in parallel with the 2nd LED part 12, and 1st bypass path BP1 is formed. Moreover, the 2nd electricity supply control means 22 is connected in parallel with the 3rd LED part 13, and forms 2nd bypass path BP2. Further, the third energization control means 23 is connected in parallel with the fourth LED portion 14 to form a third bypass path BP3. Furthermore, the fourth LED current control transistor 24B is connected in parallel with the LED driving means 3 ′ to form a fourth bypass path BP4, and the first LED unit 11, the second LED unit 12, the third LED unit 13 and the fourth LED unit. The amount of energization to the LED unit 14 is controlled.
(Backflow prevention diode)

  Each bypass path is provided with a backflow prevention diode. Specifically, the first backflow prevention diode 121 is provided in the first bypass path BP1, the second backflow prevention diode 122 is provided in the second bypass path BP2, and the third backflow prevention diode 123 is provided in the third bypass path BP3. A fourth backflow prevention diode 124 is provided in each of the fourth bypass paths BP4.

  Here, the first LED unit 11 is not provided with a bypass path or an energization control unit connected in parallel. This is because the first energization control means 21 connected in parallel with the second LED unit 12 controls the current amount of the first LED unit 11. For the fourth LED unit 14, the fourth LED current control transistor 24B performs current control.

The LED driving device 400 ′ of FIG. 11 includes a resistor as the LED driving means 3 ′. The resistor is connected in parallel with the current limiting means 3 and is connected in series with the fourth LED unit 14. In the example of FIG. 11, the current limiting means 3 is also used as the fourth LED current control transistor 24B. The fourth LED current control transistor 24B, which is the current limiting means 3 connected in parallel, and the resistor, which is the LED driving means 3 ′, form an LED drive circuit, and go to the first LED section 11 to the fourth LED section 14. Control energization. In the example of FIG. 11, by connecting a resistor as an LED drive circuit in parallel with the fourth LED current control transistor 24 </ b> B that is the fourth energization control unit 24, when the amount of current increases, By bypassing the energized current to the resistor, the load on the fourth energization control means 24 is reduced. However, if the fourth energization control means 24 has sufficient current resistance, the LED drive circuit may be omitted.
(Current control means 30B)

  The current control unit 30B is a member that controls the first energization control unit 21 to the fourth energization control unit 24 corresponding to each LED unit to perform current drive at an appropriate timing. The current control means 30B outputs an operation control signal for controlling the operation of the energization control means using the rectified voltage rectified by the rectifier circuit 2 as a reference voltage. Thereby, the amount of current on the output line OL detected by the current detection means 4 can be controlled to a value proportional to the rectified voltage. As a result, the input current of the entire circuit becomes a waveform proportional to the AC input voltage, and harmonics can be suppressed.

  A switching element such as a transistor can also be used for the current control means 30B of FIG. In particular, the bipolar transistor can be suitably used for detecting the amount of current. In this example, the current control means 30B is composed of an operational amplifier 30B. Needless to say, the current control means is not limited to an operational amplifier, and can be constituted by a comparator, a bipolar transistor, a MOSFET, or the like.

  In the example of FIG. 11, the current control means 30B controls the operation of the LED current control transistors 21B to 24B. That is, each current detection operational amplifier controls the energization amount to switch the LED current control transistor to OFF / current control / ON.

  The current control means 30B of FIG. 11 composed of an operational amplifier is generated by the forced turn-off signal generated by the forced turn-off means 8 and the harmonic suppression voltage generation means 6 at the non-inverting input terminal which is one input of the operational amplifier. Input harmonic suppression voltage. In addition, a current detection signal based on the amount of current flowing on the output line OL is input from the current detection means 4 to the inverting input terminal. Based on the sum of the fluctuation of the rectified voltage detected by the harmonic suppression voltage generation means 6 and the current detection signal detected by the current detection means 4, the current control means 30B The operations of the energization control means 21 and the current limiting means 3 are controlled.

In this way, by applying a forced turn-off signal and a harmonic suppression voltage to one input of the operational amplifier, the LED is easily forcibly turned off by disabling the harmonic suppression voltage in a section where the forced turn-off signal acts. It becomes possible. The current control means 30B has a circuit operation to be invalidated by dropping a signal instructing output to 0V.
(Current detection means 4)

The current detection means 4 is a member for detecting a current supplied to the LED assembly 10 in which the LED units are connected in series by a voltage drop or the like. By performing current detection with the current detection means 4, current driving of each LED unit constituting the LED assembly 10 is performed. The current detecting means 4 also functions as a protective resistor for the LED. Further, in order to drive the current based on the current detection signal detected by the current detection means 4, the current detection means 4 is connected to an operational amplifier 30B which is a current control means 30B for controlling the current circuit. In this circuit example, the first energization control means 21, the second energization control means 22, the third energization control means 23, the fourth energization control means 24, and the current control means 30B constitute a kind of constant current circuit.
(Current control signal applying means 5)

  Further, a current control signal applying means 5 is interposed between the current control means 30B and each energization control means. For example, since a potential difference is generated between the operation control signal applied to the first energization control unit 21 and the operation control signal applied to the fourth energization control unit 24, the first energization control unit 21 is provided by providing the current control signal applying unit 5. It is possible to reliably switch the operation of the fourth energization control means 24. Each current control signal applying means 5 defines at which current timing each LED current control transistor is turned on / off. Here, as the input voltage increases, the current control signal applying Zener diodes 5E, 5F, and 5G are provided as the current control signal applying means 5 so that the first to fourth LED current control transistors 21B to 24B are turned off in this order. Set and arranged. In the example of FIG. 11, the current control signal applying unit 5 is configured by a Zener diode, but may be configured by a resistor, a diode, or the like.

In the circuit example of FIG. 11, energization is performed in the order from the first LED unit 11 to the second LED unit 12, the third LED unit 13, and the fourth LED unit 14 as the input voltage rectified by the rectifier circuit 2 increases. The amount can be controlled. When the input voltage decreases, the LEDs are turned off in the reverse order.
(Harmonic suppression signal generation circuit)

On the other hand, in the circuit example of FIG. 11, the current control unit 30 </ b> B is configured by an operational amplifier 30 </ b> B, and the operational amplifier 30 </ b> B is controlled by the harmonic suppression voltage generation unit 6. The harmonic suppression voltage generation means 6 includes a harmonic suppression signal generation circuit. The harmonic suppression signal generation circuit includes harmonic suppression signal generation resistors 60 and 61 and a harmonic suppression signal generation capacitor 62 connected in parallel with the harmonic suppression signal generation resistor 61. The harmonic suppression signal generation circuit divides the rectified voltage rectified by the rectifier circuit 2. In other words, the rectified voltage is compressed to an appropriate level. A harmonic suppression signal which is a sine wave compressed by the harmonic suppression signal generation circuit is input to the non-inverting input terminal of the operational amplifier 30B which is the current control means 30B.
(Forced turn-off circuit 8B)

  Further, the light emitting diode driving device 400 ′ of FIG. 11 includes a forced light-off circuit 8 </ b> B as the forced light-off means 8. The forced extinction circuit 8B is connected in parallel with the harmonic suppression signal generation circuit between the output side of the rectifier circuit 2 and the non-inverting input terminal of the operational amplifier 30B that is the current control means 30B. The forced extinguishing circuit 8B includes a variable resistor, a plurality of Zener diodes, a plurality of resistors, and a plurality of transistors. The transistors include a first forced turn-off transistor and a second forced turn-off transistor, and here are constituted by a first forced turn-off FET 81 and a second forced turn-off FET 82. The drain side of the first forced extinguishing FET 81 is connected to the output side of the rectifier circuit 2 via the first drain side resistor 83. The gate side of the first forced extinguishing FET 81 is grounded via the gate side Zener diode 84. Further, a forced turn-off variable resistor 85 is connected to the gate side of the first forced turn-off FET 81. One end (upper end in FIG. 11) of the forced turn-off variable resistor 85 is connected to the output side of the rectifier circuit 2 via the resistor 86 and the first Zener diode 87, and the other end (lower end in FIG. 11) is ground resistance. It is grounded via a device 88. Further, the source side of the first forced-off FET 81 is grounded via the second Zener diode 89 and is connected to the gate side of the second forced-off FET 82. The drain side of the second forced extinguishing FET 82 is connected to the non-inverting input terminal of the operational amplifier 30B via the second drain side resistor 99. Further, the source side of the second forced extinguishing FET 82 is grounded.

The operating principle of the forced extinction circuit 8B will be described. When the rectified voltage is low, the voltage at the midpoint of the forced turn-off variable resistor 85 connected to the output side of the rectifier circuit 2 via the first Zener diode 87 and the resistor 86 is also low. When the gate-source voltage V _gs is lower than the gate threshold voltage (about 4 V), the first forced extinction FET 81 is maintained in the OFF state. As a result, the first drain side resistor 83 is not energized, the second forced extinction FET 82 is turned on, and as a result, a low voltage is input to the non-inverting input terminal of the operational amplifier 30B, and the first drain side resistor 83 is turned off. The first LED current control transistor 21B and the like are turned off.

On the other hand, when the voltage at the midpoint of the forced turn-off variable resistor 85 exceeds the threshold voltage (for example, about 4 V) of the gate-source voltage V _gs of the first forced turn-off FET 81, the first forced turn-off FET 81 is turned on. As a result, the gate-source voltage of the first forced turn-off FET 81 decreases, and the second forced turn-off FET 82 connected to the drain side of the first forced turn-off FET 81 is switched to the OFF state. As a result, the drain-source voltage of the second forced extinguishing FET 82 decreases, the potential of the non-inverting input terminal of the operational amplifier 30B increases, and the first LED current control transistor 21B and the like are turned on. .

In the circuit example of FIG. 11, the forced turn-off circuit 8B detects the rectified voltage with a Zener diode and a resistance voltage divider, and adjusts the resistance voltage dividing ratio with the forced turn-off variable resistor 85. Since the forced turn-off variable resistor 85 can adjust the forced turn-off voltage value in this way, the timing for starting the turn-off period can be changed with the forced turn-off variable resistor 85. Here, how the extinction period is adjusted with the forced extinction variable resistor 85 of the forced extinction circuit 8B will be described with reference to FIGS. In these figures, FIG. 12 is a graph showing a waveform showing a time change of the input AC voltage of the LED drive circuit and the power of the first LED unit 11 according to the comparative example of FIG. 1, and FIG. FIG. 14 is a graph showing a waveform showing a time change of the power of the first LED unit 11 when the input AC voltage of the device 400 ′ and the extinguishing period are set to T _OFF1 , and FIG. 14 is an input of the LED driving device 400 ′ of FIG. FIG. 15 is a graph showing a waveform showing a temporal change in power of the first LED unit 11 when the AC voltage and the OFF period are set to T _OFF2 , and FIG. 15 is an input AC voltage of the LED driving device 400 ′ in FIG. The graph which shows the waveform which shows the time change of the electric power of the 1st LED part 11 at the time of setting a period to _TOFF3 is shown, respectively. As is apparent from these graphs, the LED driving circuit according to the comparative example has a short extinction period T _OFF0 , and in general lighting, the extinguishing period is shortened as much as possible to suppress flicker. It is possible to set a longer light extinction period. As the turn-off period is lengthened, the turn-on period is also shortened, and the cumulative value of the illuminance, that is, the integrated value is reduced, but it has been confirmed by the present inventors' test that it is advantageous in plant growth (see FIG. 4). ).
(Constant voltage power supply 7)

  The operational amplifier 30 </ b> B is driven by the constant voltage power supply 7. The constant voltage power supply 7 includes an operational amplifier power supply transistor 70, a Zener diode 71, and a Zener voltage setting resistor 72. The constant voltage power supply 7 supplies power to the operational amplifier 30B only during a period in which the rectified voltage after the AC power supply AP is rectified by the rectifier circuit 2 exceeds the Zener voltage of the Zener diode 71. This period is set to include the lighting period of the LED assembly 10. In other words, the operational amplifier 30B is operated during the lighting of the LED assembly 10 to control the lighting.

  On the other hand, a voltage which is a current detection signal detected by the current detection resistor 4 is input to the inverting input terminal of each operational amplifier 30B. The voltage of the current detection resistor 4 is controlled such that the current is controlled along a sine wave applied to the non-inverting input terminal of the operational amplifier 30B. Thus, since the current control operation is performed along the sine wave, the LED drive current has a waveform approximated to a sine wave.

Each LED section can be configured by connecting a plurality of light emitting diode elements in series with each other. As a result, the rectified voltage can be effectively divided by a plurality of light emitting diode elements, and variations in forward voltage V _f and temperature characteristics for each light emitting diode element can be absorbed to some extent, and control in units of blocks can be made uniform. . However, the number of LED units and the number of light emitting diode elements constituting each LED unit can be arbitrarily set according to required brightness, input voltage, etc., for example, the LED unit can be configured with one light emitting diode element, It goes without saying that finer control can be performed by increasing the number of LEDs, or conversely, the control can be simplified by using only two LED units.

  In the above configuration, the number of LED units is four, but it goes without saying that the number of LED units can be two, three, or five or more as described above. In particular, by increasing the number of LED portions, a sinusoidal current waveform can be formed from a lower power supply voltage, and harmonic components can be further suppressed. In the example of FIG. 11, the switching operation in which each LED unit is turned ON / OFF is divided almost evenly with respect to the input current. However, it is not necessarily equal, and the LED unit is switched with a different current. Also good.

In yet above example, divided LED into four LED unit, each LED unit is configured to respectively the same V _f, it may not be the same for V _f. For example, if V _{f of the} LED unit 1 can be set as low as possible, that is, about 3.6 V for one LED, the current rise timing can be advanced and the fall timing can be delayed. This is further advantageous for reducing harmonics. If this method is used, the number of LED units and the V _f setting can be freely selected, and the current waveform can be approximated to a sine wave, so that it is easy to realize higher harmonics and suppression of harmonics. .
<Example 2>
(Peak illumination variable circuit)

  Further, the present invention may add a variable function in addition to the configuration in which the peak illuminance of the illumination light is fixed. Thereby, not only control of the light extinction period but also adjustment of the peak illuminance, that is, the amplitude side can be performed, so that it is possible to perform light control while maintaining the light extinction period. An example of such a circuit is shown in FIG. 16 as a light emitting diode driving apparatus 700 according to the second embodiment. The light emitting diode driving device 700 shown in this figure includes a peak illuminance adjusting means 90 in addition to the configuration of FIG. The peak illuminance adjusting means 90 replaces the harmonic suppression signal generating resistor 61 which is a fixed resistor in the circuit example of FIG. 11, and the light emitted from the LED unit such as the first LED unit 11 or the second LED unit 12 emits light. The peak illuminance variable resistor 91 for adjusting the peak illuminance is provided. This makes it possible to adjust the light intensity independently while making the peak illuminance variable and adjusting the timing of the extinction period, that is, making the OFF duty variable.

  In the above embodiment, as a method for adjusting the timing of starting the turn-off of the LED unit, a configuration in which a rectified voltage obtained by rectifying an AC voltage is detected and turned on in a period longer than a set voltage is employed. However, the present invention does not limit the method for adjusting the turn-off timing to the above, and other methods can also be adopted. For example, a method of controlling the AC energization time using a triac, a thyristor, an IGBT, or the like, or a method of inserting a commercially available dimmer using these elements into the AC AC input side can be used.

  The light emitting diode driving device and the plant cultivation illumination using the light emitting diode drive device described above can be suitably used as an application requiring adjustment of the extinguishing period, for example, plant cultivation illumination. Further, the present invention is not limited to plant cultivation, but can be applied to other uses that require adjustment of the light extinction period, such as a fishing light for collecting fish and lighting for attracting or avoiding insects.

100, 200, 300, 400, 400 ′, 500, 700, 1000... LED driving device 2... Rectifier circuit 3 .. current limiting means; 3 '.. LED driving means 4 ... current detecting means 5. 5E, 5F, 5G ... Zener diode 6 with current control signal applied ... Harmonic suppression voltage generating means 7 ... Constant voltage power supply 8 ... Forced turn-off means; 8B ... Forced turn-off circuit 9 ... Communication means 10 ... LED assembly 11 ... First LED Part 12 ... Second LED part 13 ... Third LED part 14 ... Fourth LED part 21 ... First energization control means; 21B ... First LED current control transistor 22 ... Second energization control means; 22B ... Second LED current control Transistor 23 ... third energization control means; 23B ... third LED current control transistor 24 ... fourth energization control means; 24B ... fourth LED current control transistor 30 ... electricity Control means; 30B ... current control means (operational amplifier)
60, 61 ... Harmonic suppression signal generation resistor 62 ... Harmonic suppression signal generation capacitor 70 ... Operational amplifier power supply transistor 71 ... Zener diode 72 ... Zener voltage setting resistor 81 ... First forced extinction FET
82 ... Second forced extinguishing FET
83 ... First drain side resistor 84 ... Gate side Zener diode 85 ... Forced extinction variable resistor 86 ... Resistor 87 ... First Zener diode 88 ... Ground resistor 89 ... Second Zener diode 90 ... Peak illuminance adjusting means 91 ... Peak illuminance variable resistor 99 ... second drain side resistor 1700 ... LED drive circuit 710 ... drive device 730 ... control unit 750 ... current source M1, M2, M3-MN ... switch LFIX, L1, L2, L3-LN ... LED
BC ... bypass capacitor; FS ... fuse AP ... AC power supply BP1 ... first bypass route; BP2 ... second bypass route; BP3 ... third bypass route BP4 ... fourth bypass route OL ... output line

Claims (14)

A rectifier circuit that can be connected to an AC power source and obtains a rectified voltage obtained by rectifying the AC voltage of the AC power source;
A first LED unit including at least one LED element connected in series with the output side of the rectifier circuit;
A second LED unit including at least one LED element connected in series with the first LED unit;
A first energization control means for controlling the energization amount to the first LED unit, connected in parallel with the second LED unit and in series with the first LED unit;
Current limiting means connected in series with the first LED part and the second LED part, and for controlling the amount of electricity to the first LED part and the second LED part,
A current detection means for detecting a current detection signal based on an amount of current flowing on an output line in which the first LED portion and the second LED portion are connected in series;
Current control means for outputting an operation control signal for controlling the operation of the first energization control means and the current limiting means according to the current detection signal detected by the current detection means;
Forced extinction in which the voltage value of the rectified voltage rectified by the rectifier circuit is set to a value higher than the first forward voltage obtained by adding the forward voltages of the series-connected LED elements constituting the first LED unit A light emitting diode driving device comprising: a forced turn-off means for generating a forced turn-off signal that operates the current control means to force the first LED part and the second LED part to be turned off for a period lower than the voltage value. The light-emitting diode driving device according to claim 1,
The light emitting diode drive in which the forced turn-off voltage value is set to a value lower than a second forward voltage obtained by adding forward voltages of series-connected LED elements constituting the first LED unit and the second LED unit apparatus. The light-emitting diode driving device according to claim 1 or 2,
A light-emitting diode driving device in which the forced turn-off means makes the forced turn-off voltage value variable. The light-emitting diode driving device according to any one of claims 1 to 3, further comprising:
Based on the rectified voltage output from the rectifier circuit, comprising harmonic suppression voltage generating means (6) for generating a harmonic suppression voltage,
The current control unit compares the current detection signal detected by the current detection unit with the harmonic suppression voltage generated by the harmonic suppression voltage generation unit, and suppresses the harmonic component. A light-emitting diode driving device which controls one energization control means and a current limiting means. The light emitting diode driving device according to claim 4,
The current control means is a light emitting diode driving device in which the harmonic suppression voltage generated by the harmonic suppression voltage generation means is invalidated by the forced extinction signal generated by the forced extinction means. The light-emitting diode driving device according to claim 5,
The current control means includes an operational amplifier;
A light-emitting diode driving device in which a forced turn-off signal generated by the forced turn-off means and a harmonic suppression voltage generated by the harmonic suppression voltage generation means are input to one input side of the operational amplifier. The light-emitting diode driving device according to any one of claims 1 to 6,
The current control means outputs an operation control signal for controlling operations of the first energization control means and the current limiting means, using the rectified voltage rectified by the rectifier circuit as a reference voltage.
Based on the sum of the fluctuation of the rectified voltage detected by the harmonic suppression voltage generation means and the current detection signal detected by the current detection means, the current control means includes the first energization control means and the current limiter. A light emitting diode driving device configured to control the operation of the means. The light-emitting diode driving device according to claim 1, further comprising:
LED driving means for controlling the energization to the first LED section and the second LED section, connected in series with the second LED section, and for bypassing the current energized to the current limiting means. And
The light emitting diode driving device, wherein the current limiting means is connected in parallel with the LED driving means. The light-emitting diode driving device according to any one of claims 1 to 8,
A light-emitting diode driving device in which a downstream side of the first energization control unit is connected between the current detection unit and the current limiting unit. The light-emitting diode driving device according to any one of claims 1 to 9, further comprising:
A light emitting diode driving device comprising peak illuminance adjusting means having a variable resistor for adjusting the peak illuminance of light emitted from the first LED unit and the second LED unit. The light-emitting diode driving device according to any one of claims 1 to 10, further comprising:
A third LED unit including at least one LED element connected in series with the first LED unit and the second LED unit;
Second energization for controlling the energization amount to the first LED part and the second LED part, which is connected in parallel with the third LED part and in series with the first LED part and the second LED part. Control means,
The current control unit is configured to output an operation control signal for controlling operations of the first energization control unit, the second energization control unit, and the current limiting unit in accordance with a current detection signal detected by the current detection unit. A light emitting diode driving device. The light-emitting diode driving device according to claim 11, further comprising:
A fourth LED unit including at least one LED element connected in series with the first LED unit, the second LED unit, and the third LED unit;
Connected to the first LED unit, the second LED unit, and the third LED unit in parallel with the fourth LED unit and in series with the first LED unit, the second LED unit, and the third LED unit. A third energization control means for controlling the energization amount,
Operation control for controlling the operations of the first energization control unit, the second energization control unit, the third energization control unit and the current limiting unit according to the current detection signal detected by the current detection unit. A light emitting diode driving device configured to output a signal. The light-emitting diode driving device according to any one of claims 1 to 12, further comprising:
A communication means for outputting the forced turn-off voltage value to an external device and receiving an evaluation signal indicating an evaluation value for the forced turn-off voltage value from the external device;
The light-emitting diode driving device, wherein the forced turn-off means is configured to be able to adjust the forced turn-off voltage value based on an evaluation signal from an external device received by the communication means.   Lighting for plant cultivation using the light emitting diode driving device according to any one of claims 1 to 13.