WO2012086790A1 - Two-terminal led light-emitting device, and led illumination device provided with same - Google Patents

Abstract

An LED light-emitting device (10) to which an alternating current functioning as a drive current is supplied via a pair of terminals (101, 102), wherein a plurality of groups of parallel LED elements (103) is connected in series, the groups of parallel LED elements (103) being formed by connecting, in parallel, the opposite poles of one or a plurality of first LED elements (1031) and second LED elements (1032) which have a light-emitting wavelength that differs from one other.

Description

Two-terminal LED light-emitting device and LED lighting device including the same

The present invention relates to a two-terminal LED light-emitting device and an LED lighting device including the same.

In recent years, lighting devices using light emitting diodes (LEDs) have been widely used as lighting devices to replace incandescent bulbs and fluorescent lamps. Here, alternating current from an alternating current power source is supplied to LED light emitting devices. There is an LED drive circuit that drives an LED element, for example, Patent Document 1 discloses two LED groups connected in parallel with opposite polarity to an AC source, and in an AC positive half cycle, Some are configured such that one of the LED groups is driven and the other half of the LED group is driven in the negative negative half cycle.

JP 2008-263203 A

In the LED light emitting device driven by the AC current from the AC power source as described above, the number of connection wirings for connecting the LED elements tends to increase, and there is room for improvement in this respect. The present invention has been made in view of the above circumstances, and provides a technique related to a two-terminal LED light-emitting device that can reduce the number of components and thereby achieve a compact and low-cost light-emitting device. For the purpose.

In order to solve the above problems, the present invention employs the following means. That is, the present invention is formed by connecting first and second LED elements having different emission wavelength ranges, each of which is composed of one or more, in reverse polar parallel. It is a two-terminal LED light-emitting device formed by connecting a plurality of parallel LED element groups in series. The two-terminal LED device according to the present invention is a parallel LED formed by connecting a first LED element and a second LED element having a light emission wavelength range different from that of the first LED element in reverse polar parallel. An element group, and a two-terminal protection circuit including two Zener diodes connected in series by sharing an anode or a cathode, wherein the two-terminal protection circuit is parallel to the parallel LED element group connected in series. It is connected. An alternating current as a drive current may be supplied to each terminal of the two-terminal LED light emitting device.

In the two-terminal LED light-emitting device configured in this way, for example, the magnitude of the total value of the drive currents supplied to the first LED element and the second LED element in each positive and negative half cycle by alternating current is adjusted. The chromaticity of white light emitted from the entire light emitting device is adjusted by adjusting the luminance of the white light emitted from the entire light emitting device and changing the supply ratio of the drive current to the first LED element and the second LED element. (Hue, color temperature) is adjusted.

As in the above configuration, the first LED element and the second LED element are connected in reverse polar parallel to each other to form a parallel LED element group, and a plurality of parallel LED element groups are arranged in series. One connection wiring for connecting each of the parallel LED element groups can be provided, and the number of parts can be reduced. The effect of reducing the number of parts becomes more prominent as the number of parallel LED element groups included in the two-terminal LED light-emitting device increases, which contributes to the compactness (miniaturization) and cost reduction of the two-terminal LED light-emitting device. it can.

When an alternating current is supplied to the two-terminal LED light-emitting device, the first LED element and the second LED element in each parallel LED element group are reversed in the positive and negative half cycles in which the current for lighting (light emission) does not flow. Biased. If a large voltage or large current is generated in such a reverse bias state, the current flows backward through the LED element in the reverse bias state, and the LED element may be damaged. On the other hand, in the two-terminal LED light emitting device according to the present invention, a plurality of the parallel LED elements connected in series, each having a two-terminal protection circuit including two Zener diodes connected in series by anode sharing or cathode sharing. The group was connected in parallel. Since Zener diodes are connected in parallel to each parallel LED element group, reverse large voltages and large currents have occurred in the first and second LED elements in each of the positive and negative half cycles. In such a case, if one of the Zener diodes breaks down, a large current in the reverse direction can be caused to flow downstream, and the LED element can be prevented from being damaged.

Further, in the two-terminal LED light emitting device of the present invention, the first LED elements are all connected to have the same polarity, and the second LED elements are all connected to have the same polarity. good. Thus, by connecting all the first LED elements to the same polarity, these can be controlled by a common control system. Similarly, by connecting all the second LED elements to the same polarity, these can be controlled by a common control system.

In the present invention, a constant current means for supplying a constant current to each of the parallel LED element groups may be further provided. Thereby, there is no possibility that the first LED element and the second LED element in each parallel LED element group are damaged or deteriorated, and the light emission characteristics are not deteriorated.

The present invention can also be understood as a dimming device for dimming any of the LED light emitting devices described above, and an illumination device (system) including the LED light emitting device and the dimming device. Moreover, in this specification, LED is a concept including organic electroluminescence (Organic Electro-Luminescence: organic EL).

According to the present invention, in a two-terminal LED light emitting device to which an alternating current as a drive current is supplied, a technology capable of realizing a reduction in the number of components and thus making the light emitting device compact and cost-effective is provided. can do.

It is a figure which shows the 1st circuit structural example of the LED light-emitting device which concerns on 1st embodiment. It is a figure which shows the 2nd circuit structural example of the LED light-emitting device which concerns on 1st embodiment. It is a figure which shows the 3rd circuit structural example of the LED light-emitting device which concerns on 1st embodiment. It is a figure which shows the 4th circuit structural example of the LED light-emitting device which concerns on 1st embodiment. It is a figure for demonstrating the modification of the constant current circuit in FIG. It is a figure which shows the 5th circuit structural example of the LED light-emitting device which concerns on 1st embodiment. It is a figure which shows the 6th circuit structural example of the LED light-emitting device which concerns on 1st embodiment. It is a figure which shows the 7th circuit structural example of the LED light-emitting device which concerns on 1st embodiment. It is a figure which shows the 8th circuit structural example of the LED light-emitting device which concerns on 1st embodiment. It is a figure which shows the circuit structural example of the white LED light modulation apparatus which concerns on 2nd embodiment. (A) shows the commercial power supply waveform applied to the dimming circuit, and (B) shows the voltage applied to the trigger diode. It is a figure which shows the outline of the circuit structure of the LED illumination system in 3rd embodiment. It is a figure which shows the structural example of the control circuit in 3rd embodiment. It is waveform explanatory drawing of the drive current supplied to LED light emitting device when performing brightness | luminance adjustment in 3rd embodiment. It is waveform explanatory drawing of the drive current supplied to LED light emitting device when performing chromaticity adjustment in 3rd embodiment.

Hereinafter, embodiments of an LED light emitting device according to the present invention will be described with reference to the drawings. The configuration of the embodiment is an exemplification, and the present invention is not limited to the configuration of the embodiment.

<First embodiment>
[First circuit configuration example]
FIG. 1 is a diagram illustrating a first circuit configuration example of the LED light emitting device 10 according to the present embodiment. The LED light emitting device 10 according to the present embodiment is a two-terminal LED device that emits white light by receiving and driving an alternating current from an alternating current power supply.

The two-terminal LED light-emitting device 10 includes two terminals (a pair of terminals) 101 and 102 and a plurality of parallel LED element groups 103 connected in series between the pair of terminals 101 and 102. In this parallel LED element group 103, a pair of LED elements having different emission wavelength ranges, that is, the first LED element 1031 and the second LED element 1032 are reversed in polarity (reverse polarity). It is formed by connecting in parallel. That is, the two-terminal LED light-emitting device 10 includes first and second LED elements 1031 and 1032 each having one or a plurality of first and second LED elements 1031 and 1032 having different emission wavelength ranges. A plurality of parallel LED element groups 103 formed in reverse polar parallel connection are further connected in series. Here, the number of LED element groups 103 connected in series is not limited to a specific number. Moreover, as shown in the figure, the two-terminal LED light emitting device 10 in the present embodiment is connected so that the first LED elements 1031 have the same polarity, and the second LED elements 1032 have the same polarity. Connected to be.

An AC current supplied from an AC power source is passed between the two terminals 101 and 102 as a drive current for causing the first LED element 1031 and the second LED element 1032 included in the parallel LED element group 103 to emit light. Is done. In each parallel LED element group 103, the first LED element 1031 and the second LED element 1032 are connected in parallel with each other in reverse polarity (that is, connected in reverse polar parallel), so that a positive current During the energization (positive AC half cycle), one of the first LED element 1031 and the second LED element 1032 is turned on (emits light) and the other is turned off. When a negative current is applied (negative half cycle of alternating current), one of the first LED element 1031 and the second LED element 1032 is extinguished and the other is lit (emits light). Thus, the two-terminal LED light emitting device 10 can be driven by an alternating current from an alternating current power source.

Here, the first LED element 1031 and the second LED element 1032 are LED elements that emit white light having different spectra (the emission wavelength ranges are different). For example, each of the first LED element 1031 and the second LED element 1032 has an emission wavelength of 410 nm and a terminal voltage at a forward current of 3.5 V. The first LED element 1031 is embedded with a phosphor that emits white light of about 5000 K (Kelvin) when stimulated (excited) with light having an emission wavelength of 410 nm. On the other hand, the second LED element 1032 is embedded with a phosphor emitting white light of about 3000 K (Kelvin) when stimulated (excited) with light having an emission wavelength of 410 nm. However, the excitation wavelength in the first LED element 1031 and the second LED element 1032 described above, the chromaticity of the emitted white light (the chromaticity is a concept including hue, color temperature, etc., and the same applies hereinafter), terminal. Each value such as voltage is an example, and may be changed as appropriate.

In the two-terminal LED light emitting device 10 configured in this way, the magnitude of the total value of the drive current supplied to the first and second LED elements 1031 and 1032 is increased or decreased in each positive and negative half cycle by the AC power supply. Thus, it is possible to adjust the luminance of white light emitted from the entire light emitting device. Moreover, the chromaticity (hue, color temperature) of the white light emitted as the whole light emitting device can be adjusted by changing the supply ratio of the drive current to the first and second LED elements 1031 and 1032.

And, like the two-terminal LED light-emitting device 10 according to the present embodiment, each parallel LED element group 103 is of a two-terminal type, so that there is an advantage that only one connection wiring is required to connect them in series. . That is, according to the two-terminal LED light-emitting device 10, it has good light-emitting characteristics and the number of components of the two-terminal LED light-emitting device 10 can be reduced. This is advantageous for making the two-terminal LED light emitting device 10 compact (downsizing) and cost reduction.

[Second circuit configuration example]
Next, FIG. 2 is a diagram illustrating a second circuit configuration example of the two-terminal LED light emitting device according to the present embodiment. Here, the description will focus on differences from the first circuit configuration example described in FIG. The two-terminal LED light-emitting device 10A is the same as the two-terminal LED light-emitting device 10 except that the configuration of the LED element group 103A directly connected to each other is different from the parallel LED element group 103 described with reference to FIG.

The parallel LED element group 103A has five first LED elements 1031 and five second LED elements 1032. The first LED element 1031 and the second LED element 1032 are connected in parallel so as to have opposite polarities as in the first circuit configuration example (that is, connected in reverse polar parallel). As can be seen from the configuration examples shown in FIGS. 1 and 2, the two-terminal LED light emitting device according to the present invention includes one or a plurality of first LED elements 1031 and second LED elements 1032 in each LED element group. Can be included. In addition, the number of the first LED elements 1031 and the second LED elements 1032 included in one parallel LED element group 103A can be changed as appropriate, and the first LED element 1031 and the second LED element 1032 can be changed. The number need not be the same.

[Third circuit configuration example]
Next, FIG. 3 is a diagram illustrating a third circuit configuration example of the two-terminal LED light emitting device according to the present embodiment. The two-terminal LED light-emitting device 10B according to this configuration example is common to the configuration of the two-terminal LED light-emitting device 10 described with reference to FIG. 1 except that the two-terminal LED light-emitting device 10B includes a two-terminal protection circuit 104 for preventing breakage of each LED element. is there. The two-terminal protection circuit 104 is formed of a series circuit composed of two Zener diodes 1041 and 1042 (constant voltage diodes) whose cathodes are connected to each other. Connected in parallel. That is, in the illustrated configuration example, a two-terminal protection circuit 104 including two Zener diodes 1041 and 1042 connected in series with a common cathode is connected in parallel to each parallel LED element group 103. However, the directions of the two Zener diodes 1041 and 1042 to be connected may be reversed, that is, the anodes may be connected. That is, a two-terminal protection circuit 104 including two Zener diodes connected in series with the anode shared may be connected in parallel to each parallel LED element group 103. As described above, the two-terminal protection circuit 104 according to the present embodiment includes the two Zener diodes 1041 and 1042 connected in series with opposite polarities, and the parallel LED element group 103 connected in series. Connected in parallel. In other words, the two-terminal LED light-emitting device 10B according to this configuration example connects the first LED element 1031 and the second LED element 1032 having a different emission wavelength range from the first LED element 1031 in reverse polar parallel. A parallel LED element group 103 to be formed, and a two-terminal protection circuit 104 including two Zener diodes connected in series by sharing an anode or a cathode, a plurality of two-terminal protection circuits 104 are connected in series. The parallel LED element group 103 is connected in parallel.

Here, when a positive current flows from the terminal 101 toward the terminal 102, the second LED element 1032 in each parallel LED element group 103 is in a reverse bias state. If the reverse bias is a large voltage or the positive current is a large current, the second LED element 1032 may flow backward, leading to damage of the second LED element 1032. On the other hand, when a positive current flows from the terminal 102 toward the terminal 101, the first LED element 1031 in each parallel LED element group 103 is reversely biased from the same viewpoint, and therefore the first LED element 1031 may be damaged.

On the other hand, in the third circuit configuration example shown in FIG. 3, for example, when a large positive current flows from the terminal 101 to the terminal 102, the second LED element 1032 in each parallel LED element group 103 is damaged. The Zener diode 1042 breaks down, and current flows to the terminal 102 side. This prevents the second LED element 1032 in each parallel LED element group 103 from being damaged. The first LED element 1031 is protected not only from the reverse overvoltage breakdown with respect to the second LED element 1032 but also from the forward overvoltage breakdown caused by a large positive current flowing from the terminal 101 to the terminal 102. It is possible at the same time.

Conversely, when a large negative current flows from the terminal 101 to the terminal 102 (when a large positive current flows from the terminal 102 to the terminal 101), the Zener diode 1041 of the two-terminal protection circuit 104 breaks down and the current is Flow to the 101 side. This prevents the first LED element 1031 in each parallel LED element group 103 from being damaged. In addition, the second LED element 1032 is protected not only from the reverse overvoltage breakdown with respect to the first LED element 1031 but also from the forward overvoltage breakdown caused by a large positive current flowing from the terminal 102 to the terminal 101. It is possible at the same time.

[Fourth circuit configuration example]
Next, FIG. 4 is a diagram illustrating a fourth circuit configuration example of the two-terminal LED light-emitting device according to the present embodiment. The two-terminal LED light emitting device 10C according to this configuration example includes a constant current circuit 20 (constant current means) for supplying a constant current to each of the parallel LED element groups. Here, reference numeral 20A denotes a first constant current circuit unit, and reference numeral 20B denotes a second constant current circuit unit. The first constant current circuit unit 20A is a circuit that limits the current to the second LED element 1032 in order to keep the current value supplied to the first LED element 1031 in each parallel LED element group 103 constant. The second constant current circuit unit 20B is a circuit that limits the current to the first LED element 1031 in order to keep the current value supplied to the second LED element 1032 in each parallel LED element group 103 constant. is there. The first constant current circuit unit 20A and the second constant current circuit unit 20B are connected in parallel with opposite polarity as illustrated. Reference numerals D1 and D2 are backflow prevention diodes. The constant current circuit 20 includes first and second constant current circuit units 20A and 20B, and diodes D1 and D2.

The first constant current circuit unit 20A includes two transistors Tr1A and Tr2A and two resistors R1A and R2A. When an alternating current is supplied from the alternating current power source to the two-terminal LED light emitting device 10C according to this configuration example, and a positive current flows from the terminal 101 to the terminal 102 in a positive half cycle, for example, the diode D1 has a forward bias. As a result, a reverse bias is applied to the diode D2. As a result, the alternating current flows on the first constant current circuit unit 20A side, but does not flow on the second constant current circuit unit 20B side.

At that time, when the collector current of the transistor Tr1A increases (that is, when the current supplied to the first LED element 1031 increases), the potential drop of the resistor R1A connected to the emitter side of the transistor Tr1A increases. The transistor Tr2A is turned on. As a result, the base current of the transistor Tr1A decreases, and as a result, the collector current of the transistor Tr1A decreases. On the other hand, when the collector current of the transistor Tr1A decreases, the reverse operation occurs, so that the collector current of the transistor Tr1A, that is, the current supplied to the first LED element 1031 is kept constant. become.

On the other hand, for example, when a positive current flows from the terminal 102 to the terminal 101 in the negative half cycle, the diode D2 is forward-biased and the diode D1 is reverse-biased. As a result, the alternating current flows on the second constant current circuit unit 20B side and does not flow on the first constant current circuit unit 20A side. Here, the second constant current circuit unit 20B has a configuration equivalent to that of the first constant current circuit unit 20A, and includes two transistors Tr1B and Tr2B and two resistors R1B and R2B. The transistors Tr1B and Tr2B and the resistors R1B and R2B in the second constant current circuit unit 20B correspond to the transistors Tr1A and Tr2A and the resistors R1A and R2A in the first constant current circuit unit 20A, and have an equivalent function. It is.

The operation state of the second constant current circuit unit 20B will be described. When the collector current of the transistor Tr1B increases in a half cycle in which a positive current flows from the terminal 102 to the terminal 101 (that is, supplied to the second LED element 1032). As the current increases, the potential drop of the resistor R1B connected to the emitter side of the transistor Tr1B increases, and the transistor Tr2B is turned on. As a result, the base current of the transistor Tr1B decreases, and as a result, the collector current of the transistor Tr1B decreases. On the other hand, when the collector current of the transistor Tr1B decreases, the reverse action occurs, so that the collector current of the transistor Tr1B, that is, the current supplied to the second LED element 1032 is kept constant. become.

Thus, since the two-terminal LED light emitting device 10C according to the present configuration example includes the constant current circuit 20 for supplying a constant current to each of the parallel LED element groups 103, the first and second LED elements There is no possibility that 1031, 1032 will be damaged or deteriorated, or that the light emission characteristics will be deteriorated. The constant current circuit 20 includes first and second constant current circuit units 20A and 20B, and diodes D1 and D2. In the two-terminal LED light emitting device 10 </ b> C shown in FIG. 4, the two-terminal protection circuit 104 shown in FIG. 3 may be connected in parallel to the parallel LED element group 103. That is, the two-terminal LED light-emitting device 10C shown in FIG. 4 is equivalent to a circuit in which the constant-current circuit 20 is combined with the two-terminal LED light-emitting device 10 shown in FIG. A two-terminal LED light emitting device 10C may be configured by combining the constant current circuit 20 with the two-terminal LED light emitting device 10B shown in FIG.

FIG. 5 is a diagram for explaining a modification of the constant current circuit in FIG. As shown in FIG. 5, instead of the constant current circuit 20 shown in FIG. 4, the constant current circuit 20 ′ shown in FIG. The current value supplied to the first and second LED elements 1031 and 1032 may be kept constant. In FIG. 4 and FIG. 5, the same reference numerals are assigned to common electronic components. The constant current circuit 20 'includes first and second constant current circuit portions 20A and 20B and diodes D1 and D2.

In FIG. 5, the first constant current circuit unit 20A and the second constant current circuit unit 20B are connected in series with opposite polarities. Further, two diodes D1 and D2 directly connected as opposite polarities are connected in parallel to the first and second constant current circuit units 20A and 20B. Further, as illustrated, a terminal formed between the first constant current circuit unit 20A and the second constant current circuit unit 20B and a terminal formed between the diode D1 and the diode D2 are connected by wiring. .

The constant current circuit 20 'having the above configuration is a circuit equivalent to the constant current circuit 20 described in FIG. That is, for example, when a positive current flows from the terminal 101 to the terminal 102 in the positive half cycle, the diode D1 is forward biased and the diode D2 is reverse biased. As a result, the current in this half cycle shunts (bypasses) the second constant current circuit unit 20B and flows through the first constant current circuit unit 20A. In this half cycle, the current supplied to the first LED element 1031 is kept constant by operating the first constant current circuit section 20A in the same manner as described in FIG.

On the other hand, for example, when a positive current flows from the terminal 102 to the terminal 101 in the negative half cycle, the diode D2 is forward-biased and the diode D1 is reverse-biased. As a result, the current in this half cycle shunts (bypasses) the first constant current circuit unit 20A and flows through the second constant current circuit unit 20B. In this half cycle, the second constant current circuit unit 20B operates in the same manner as described with reference to FIG. 4, so that the current supplied to the second LED element 1032 is kept constant. Here, in the two-terminal LED light emitting device 10 </ b> C shown in FIG. 5, the two-terminal protection circuit 104 shown in FIG. 3 may be connected in parallel to the parallel LED element group 103. That is, the two-terminal LED light-emitting device 10C shown in FIG. 5 is equivalent to a circuit in which the constant-current circuit 20 ′ is combined with the two-terminal LED light-emitting device 10 shown in FIG. The two-terminal LED light-emitting device 10C shown in FIG. 3 may be combined with the constant-current circuit 20 ′ to form the two-terminal LED light-emitting device 10C. It should be noted that, by using a constant current diode (CRD, Current Regulative Diode) or the like instead of the constant current circuits 20 and 20 ′ described in FIG. 4 and FIG. . 4 and 5, the transistor may be a bipolar transistor as shown in the figure, or the bipolar transistor may be replaced with a field effect transistor (FET). The diodes D1 and D2 may be omitted when an FET is used instead of the bipolar transistor. The FET generates a small amount of heat and is suitable for connecting LED elements in parallel.

FIG. 6 is a diagram showing a fifth circuit configuration example of the two-terminal LED light-emitting device according to this embodiment. FIG. 7 is a diagram illustrating a sixth circuit configuration example of the two-terminal LED light-emitting device according to this embodiment.

A two-terminal LED light-emitting device 10D shown in FIG. 6 includes two terminals 101 and 102, a first LED group 203 connected in parallel with the opposite polarity between the two terminals 101 and 102, and a second LED group 204. ing. The first LED group 203 and the second LED group 204 constitute an LED light emitting unit.

Each of the first LED group 203 and the second LED group 204 includes one or more predetermined numbers of LED elements connected in series. The number of LED elements constituting the first LED group 203 and the second LED group 204 can be set as appropriate. In addition, it is not an essential requirement that the number of LED elements constituting the first and second LED groups 203 and 204 is the same, and each of the first and second LED groups 203 and 204 is composed of a desired number of LED elements. can do.

In the two-terminal LED light emitting device 10D, when an alternating current is supplied between the terminals 101 and 102, one of the first LED group 203 and the second LED group 204 (for example, the first LED group 203) is a positive half cycle of the alternating current. Light is emitted, and the other (for example, the second LED group 204) emits light in a negative half cycle. Thus, the two-terminal LED light-emitting device D can be driven with an alternating current from an alternating current source.

The first LED group 203 and the second LED group 204 may have the same light emission characteristics. Alternatively, the first and second LED groups 203 and 204 may have different spectral characteristics and may have different color temperatures and colors (light emission wavelength ranges).

For example, when the first LED group 203 and the second LED group 204 are white light sources that emit white light and emit different spectra (light emission wavelength ranges are different), the first and second LED groups 203 in each positive and negative cycle. , 204, the luminance of the LED light emitting unit can be adjusted by increasing / decreasing the total value of the drive currents supplied to. Further, by changing the ratio of the drive current to the first and second LED groups 203 and 204, it is possible to change the color temperature of light emission of the LED light emitting unit. Thereby, the color temperature of white light can be changed over a wide range, for example, from a light bulb color to daylight white.

The two-terminal LED light emitting device 10D further includes a first protection circuit 205 and a second protection circuit 206 that are connected in parallel to the first LED group 203 and the second LED group 204 between the terminals 101 and 102. . The protection circuit 205 includes a Zener diode 207 and a diode 208 having anodes connected to each other, and is connected in parallel to the first and second LED groups 203 and 204. On the other hand, the protection circuit 206 includes a Zener diode 209 and a diode 210 whose cathodes are connected to each other, and are connected in parallel to the first and second LED groups 203 and 204.

According to the above configuration, when a positive current flows from the terminal 101 to the terminal 102, the first LED group 203 is in a state in which a reverse bias is applied. If this reverse bias is a large voltage or if the positive current is a large current, the current may flow backward through the first LED group 203 and the first LED group 203 may be damaged. This can also occur for the second LED group 204 when a positive current flows from the terminal 102 toward the terminal 102.

On the other hand, in the two-terminal LED light emitting device 10D, when a positive large current flows from the terminal 101 to the terminal 102, the Zener diode 207 breaks down before the first LED group 203 is damaged, and the current flows to the terminal 102 side. Shed. Thereby, damage to the first LED group 203 can be prevented.

Conversely, when a large negative current flows from the terminal 101 to the terminal 102 (when a large positive current flows from the terminal 102 to the terminal 101), the Zener diode 209 of the protection circuit 206 breaks down and the current flows to the terminal 101 side. To flow. Thereby, it is possible to prevent the second LED group 204 from being damaged. In FIG. 6, the diodes 208 and 210 may be omitted. In this case, the Zener diodes 207 and 209 are individually connected in parallel to the first LED group 203 and the second LED group 204.

7 shows an equivalent circuit of the protection circuits 205 and 206 shown in FIG. The protection circuit 211 is formed of a series circuit including two Zener diodes 212 and 213 in which cathodes are connected to each other, and is connected in parallel to the first LED group 203 and the second LED group 204 between the terminals 101 and 102. ing. However, the directions of the two Zener diodes 212 and 213 to be connected may be reversed (the anodes may be connected to each other).

According to the two-terminal LED light emitting device 10E shown in FIG. 7, the first LED group 203 can be protected by the breakdown of the Zener diode 213 against a positive large current from the terminal 101 side. On the other hand, the second LED group 204 can be protected by the breakdown of the Zener diode 212 against a negative large current (positive current flowing from the terminal 102 to the terminal 101) from the terminal 101 side.

8 and 9 show seventh and eighth circuit configuration examples of the two-terminal LED light-emitting device to which the protection circuit shown in FIGS. 6 and 7 can be applied, and a protection circuit for the two-terminal LED light-emitting devices 10F and 100G. An example to which 211 is applied is shown.

In the two-terminal LED light emitting device 10F shown in FIG. 8, a plurality of parallel LED element groups 221 that are LED parallel circuits composed of a first LED 222 and a second LED 223 connected in parallel are connected in series between a pair of terminals 101 and 102. Become. Each of the first LED 222 and the second LED 223 includes at least one LED element. The configurations of the first LED group 203 and the second LED group 204 can be applied to the configuration of the first LED 222 and the second LED 223. The protection circuit 211 is connected in parallel to a plurality of parallel LED element groups 221 connected in series.

According to the two-terminal LED light emitting device 10F, when a large current flows from the terminal 101 to the terminal 102, the first LED 222 is protected by the breakdown of the Zener diode 213 before each first LED 222 is damaged. Conversely, when a large current flows from the terminal 102 to the terminal 101, the Zener diode 212 breaks down, thereby preventing the second LEDs 223 from being damaged.

The two-terminal LED light-emitting device 10G shown in FIG. 9 is different in that a parallel LED element group 224 in which a plurality of first LEDs 222 and a plurality of second LEDs 223 are connected in parallel is applied instead of the parallel LED element group 221. Different from the terminal LED light emitting device 10F. Since other points are the same as the two-terminal LED light-emitting device 10F, detailed description thereof is omitted. The Zener diodes 212 and 223 may be individually provided for the LED parallel circuits 221 and 224. Moreover, although the example which applied the protection circuit 211 with respect to 2 terminal LED light-emitting device 10F, 10G was shown, the protection circuit 205,206 may be applied with respect to 2 terminal LED light-emitting device 10F, 10G.

According to the two-terminal LED light-emitting devices 10D to 10G, the protection circuits 205 and 206 or the protection circuit 211 are provided, so that the first LED group 203 (first LED 222) and the first LED are between the terminal 101 and the terminal 102. Even when a large current in the reverse direction occurs with respect to one of the two LED groups 204 (second LED 223), the first LED group 203 (first LED 222) and the second LED group 204 (second LED 223) are protected by breakdown of the Zener diode, These damages can be prevented.

In the examples shown in FIGS. 6 to 9, the LED circuit with the protection circuit in which the two-terminal LED light emitting device (LED circuit) and the protection circuit are integrated is schematically shown. The protection circuit may be connected to the LED circuit as needed. Further, the constant current circuit 20 shown in FIG. 4 or the constant current circuit 20 ′ shown in FIG. 5 may be combined with the two-terminal LED light emitting device shown in FIGS.

In the two-terminal LED light emitting device described above, a fuse is provided at a predetermined position between the terminal 101 and the terminal 102 (for example, between the terminal 101 and each LED (group)), and the fuse is blown when a large current is generated. Each LED (group) may be protected.

<Second embodiment>
Next, a second embodiment will be described. Here, an embodiment in which each light emitting device described in the first embodiment is mounted on the light control device Dm that is the control device will be described in detail as an example. FIG. 10 is a diagram illustrating a circuit configuration example of the light control device (color control device) according to the present embodiment. In FIG. 10, any of the light emitting devices of the first to eighth circuit configuration examples described above can be suitably applied to the light control device Dm, and the white illumination light obtained by the light emission of the LED element included in the light emitting device can be used. Adjust the chromaticity (hue, color temperature). Here, an example will be described in which the two-terminal LED light-emitting device 10 (first circuit configuration example) described in FIG. 1 is mounted on the dimming device Dm. Instead, the two-terminal LED according to another circuit configuration example is described. Of course, it does not matter if a light emitting device (10A to 10G) is incorporated.

In this figure, since the configuration of the two-terminal LED light-emitting device 10 has already been described, a detailed description thereof is omitted here. The light control device Dm includes an AC power supply input terminal 1, a triac 30, a trigger diode 40, a time constant circuit 50, a hysteresis removal circuit 70, a protection circuit 80, and the like.

The AC power input terminal 1 is a terminal for supplying power from a commercial power supply (AC 100 V) into the dimming circuit, and includes a plug for connecting to the commercial power supply. One of the AC power supply input terminals 1 is connected to the input terminal 101 of the two-terminal LED light emitting device 10.

The triac 30 is connected to the input terminal 102 of the two-terminal LED light-emitting device 10, and energizes the alternating current input from the alternating-current power supply input terminal 1 during the energization period during one alternating cycle for each parallel LED element group 103. To do. When the triac 30 is turned on (ignited) at a certain point in a half cycle, it continues to supply a positive or negative current to the terminal 102 until the half cycle ends.

The trigger diode 40 supplies the triac 30 with a trigger signal for the triac 30 to fire. The time constant circuit 50 controls the timing at which the trigger diode 40 supplies a trigger signal to the triac 30. The time constant circuit 50 includes a diode 51, a resistor 52, and a variable resistor 53 connected in series, a diode 61, a resistor 62, a variable resistor 63, and a capacitor (capacitor) 54 connected in series. The trigger diode 40 is connected. The variable resistors 53 and 63 are provided with an operation unit (such as a knob) for individually adjusting these resistance values.

The resistor 52, the variable resistor 53, and the capacitor 54 constitute a CR time constant circuit that charges the voltage applied to the trigger diode 40 in an AC positive half cycle (first half cycle). The trigger diode 40 is turned on according to the determined time constant. The diode 51 is a backflow prevention diode. On the other hand, the resistor 62, the variable resistor 63, and the capacitor 54 constitute a CR time constant circuit that charges the applied voltage to the trigger diode 40 in the negative half cycle of the alternating current (second half of the cycle). The trigger diode 40 is turned on according to a time constant determined by the value.

11A shows a commercial power supply waveform applied to the dimming circuit according to the dimming device Dm, and FIG. 11B shows a voltage applied to the trigger diode 40 (state of charge on the capacitor 54). ). As shown to FIG. 11 (A), the alternating voltage of a sine curve is applied to the light control circuit of the light control apparatus Dm. In the positive half cycle, simultaneously with the start of voltage application, positive charging of the capacitor 54 of the time constant circuit 50 is started, and at a time t1 when the charge charged in the capacitor 54 reaches a predetermined amount, the trigger diode 40 triggers the trigger signal. Is supplied to the triac 30, and the triac 30 is ignited to start supplying a positive current to the two-terminal LED light emitting device 10. In the configuration example of FIG. 10, in an AC positive half cycle, a positive current flows from the terminal 101 to the terminal 102 in the two-terminal LED light-emitting device 10. Therefore, only the first LED element 1031 in each parallel LED element group 103 is turned on (emits light), and the second LED element 1032 is maintained in an extinguished state. Such current supply continues until the end of the half cycle. On the other hand, in the negative half cycle, a similar operation is performed with the polarity opposite to that of the positive half cycle, the triac 30 is ignited at time t 2, and a negative current is supplied to the light emitting device 20. In this case, a positive current flows from the terminal 102 to the terminal 101 in the two-terminal LED light emitting device 10. Therefore, in the negative half cycle, only the second LED element 1032 in each parallel LED element group 103 is turned on (emits light), and the first LED element 1031 is maintained in an extinguished state.

Thus, in each positive and negative half cycle, the triac 30 is ignited at a timing according to the time constant of the time constant circuit 50, and a drive current is supplied to the two-terminal LED light emitting device 10. A hatched portion in FIG. 11A indicates a voltage (current) supplied to the two-terminal LED light-emitting device 10 in positive and negative half cycles. The time constant varies depending on the resistance values of the variable resistors 53 and 63. That is, the smaller the resistance value of the variable resistor 53, the smaller the time constant and the earlier the timing at which the triac 30 is fired. In this way, by changing the resistance values of the variable resistors 53 and 63, the energization time during the half cycle for the first and second LED elements 1031 and 1032 included in each parallel LED element group 103, that is, the current value. Can be made variable. The resistance values of the variable resistors 53 and 63 can be individually operated. Therefore, the light control device Dm according to the present embodiment can individually control (adjust) the energization time in the positive and negative half cycles.

The hysteresis removal circuit 70 is a circuit for removing the residual charge charged in the capacitor 54 before the end of the positive and negative half cycles of the alternating current to remove the hysteresis. The protection circuit 80 is connected in parallel to the two-terminal LED light-emitting device 10 and the triac 30, and one end thereof is connected to the terminal 101 of the two-terminal LED light-emitting device 10, and one is grounded. The protection circuit 80 includes Zener diodes 81 and 82, and when the impulse or surge occurs, it breaks down and protects the two-terminal LED light emitting device 10.

Next, an operation example (operation example) of the light control device Dm will be described. First, the operation units of the variable resistors 53 and 63 are operated to set each of these resistance values to the maximum value. The plug of the AC power input terminal 1 is connected to a commercial power supply 100V (not shown). Then, an alternating voltage (alternating current) is supplied to the dimming circuit of the dimming device Dm.

Then, the current indicated by the oblique lines in FIG. 11A flows through the two-terminal LED light emitting device 10 (load). As a result, each of the first and second LED elements 1031 and 1032 emits light intermittently in the latter half of each half cycle and feels lit dark to the human eye. Specifically, the first LED element 1031 emits light in the second half of the positive half cycle, and the second LED element 1032 emits light in the second half of the negative half cycle.

Here, if the resistance value is decreased by operating the operation section of the variable resistor 63 (for example, the dial knob (light amount operation knob) for operating the variable resistor 63), the firing timing of the triac 30 is advanced, The average current value in the negative half cycle of the alternating current increases, and the human eye feels that it is lit slightly brighter. Further, if the resistance value is decreased by operating the operation section of the variable resistor 53 (for example, the dial knob (color tone operation knob) for operating the variable resistor 53), the average current in the positive half cycle of the AC current is reduced. The value increases and the human eye feels more lit. At this time, since the 5000 K white light emitted from the first LED element 1032 occupies the main proportion of the entire luminance (light emission amount) of the light emitting device 10, it is more than when only the second LED element 1032 is turned on. Not only is it bright, it feels like the color temperature has risen.

As described above, according to the light control device Dm according to the present embodiment, the first and second LED elements 1031 and 1032 that emit white light having different chromaticities (hue and color temperature) are connected to each of the alternating currents. Since the variable resistors 53 and 63 corresponding to the half cycle can be individually controlled, the chromaticity of light emitted from the two-terminal LED light-emitting device 10 can be freely adjusted.

<Third embodiment>
Next, a third embodiment will be described. Here, the form which mounts each light-emitting device demonstrated in 1st embodiment in LED lighting system LS is demonstrated in detail exemplarily. Any of the light emitting devices of the first to eighth circuit configuration examples described above can be suitably applied to the LED lighting system LS in the present embodiment. Here, an example in which the two-terminal LED light-emitting device 10 (first circuit configuration example) shown in FIG. 1 is mounted on the LED illumination system LS will be described, but instead of this, a light-emitting device according to another circuit configuration example ( Of course, 10A to 10G) may be incorporated.

Next, the LED lighting system LS according to this embodiment will be described. In this LED illumination system LS, a pair of power supply lines from a power source is connected to the light control device Dm, and the light control device Dm and the two-terminal LED light emitting device 10 are a pair of power supply lines (drive current supply lines). The wiring structure is connected by. In the illumination system LS according to the present embodiment, a pair of lead-in wires are drawn from the power source (commercial power supply) to the installation position of the light control device Dm, and the installation position of the light control device Dm and the two-terminal LED light emitting device 10 It is suitably applied to a building in which a pair of two feeders is laid in advance between the installation arrangement of the two. In such a case, it can supply to the 2 terminal LED light-emitting device 10 adjusted with the control circuit mounted in the light modulation apparatus Dm.

FIG. 12 is a diagram showing an outline of the circuit configuration of the LED illumination system in the third embodiment, and FIG. 13 is a diagram showing a configuration example of the control circuit shown in FIG. FIG. 12 shows an electric wiring installation space (upper side of the virtual line 403) with a virtual line 403 represented by a two-dot chain line as a boundary, a light control device Dm (light control box) to which the electrical wiring is connected, and a two-terminal LED. The installation space (below the virtual line 403) of the LED illumination system LS in which the light emitting device 10 is disposed is illustrated.

The electrical wiring installation space is usually provided in the wall or behind the ceiling, and is isolated from the installation space of the LED lighting system LS by the wall or ceiling. In the example shown in FIG. 12, in the electrical wiring installation space, a pair of commercial power buses 400 to which a commercial power source (for example, AC 100V, 50 Hz) is supplied, and a pair of lighting device power supply lines 401 (401a, 401b) A pair of lighting device blinking wires 402 that are led out from the commercial power source bus 400 are provided.

The lead-in wire 402 is connected to a pair of terminals T1 and T2 on the input side of the light control device Dm. The dimmer Dm has a pair of terminals T3 and T4 on the output side, and the terminals T3 and T4 are connected to the lighting device power supply line 401 (401a and 410b). On the other hand, a two-terminal LED light emitting device 10 having a pair of terminals 101 and 102 is connected to the illuminator device power supply line 401. The two-terminal LED light emitting device 10 is the same as the LED light emitting device 10 described in the first and second embodiments.

The dimmer Dm receives AC voltage from a commercial power source supplied from the terminals T1 and T2. The light control device Dm includes a full-wave rectification type DC power supply circuit (hereinafter abbreviated as “power supply circuit”) 412. The light control device Dm can provide a stable DC power supply regardless of the conduction state of the load by the power supply circuit 412. The power supply circuit 412 is connected to the control circuit 413 via DC power supply lines 414 and 415. When the commercial AC power supply has an effective value of 100 V, the power supply circuit 412 becomes a DC power supply that supplies a DC voltage of approximately 140 V through the feeder lines 414 and 415 when there is no load.

As shown in FIG. 13, the control circuit 413 includes an operation amount detection unit 417 connected to the operation unit 416, a control device 420, and a drive device 430. The drive device 430 includes a drive logic circuit (control circuit) 431 and a drive circuit 432 that is an H-type bridge circuit. The output terminal of the drive circuit 432 is connected to the terminals T3 and T4, and is connected to the two-terminal LED light-emitting device 10 via the illuminator device power supply line 401. The two-terminal LED light-emitting device 10 is as described in the first embodiment, but the first LED element 1031 and the second LED element 1032 having different emission wavelength ranges are reversed in polarity. A plurality of parallel LED element groups 103 connected in parallel with each other (in reverse polarity) are connected in series.

The operation unit 416 is an operation device for performing adjustment (light control) of luminance (light emission amount) of light emitted from the two-terminal LED light-emitting device 10 and adjustment (color control) of chromaticity (hue, color temperature). . More specifically, the operation unit 416 includes a light adjustment operation dial 416A and a color adjustment operation dial 416B. The user can adjust the luminance (light emission amount) and chromaticity (hue, color temperature) of the two-terminal LED light emitting device 10 by rotating the dials 416A and 416B.

The operation amount detection unit 417 is a signal generator that outputs a signal corresponding to the rotation amount (rotation angle) of the dial, which is the operation amount of each operation dial 416A, 416B. In the present embodiment, the operation amount detector 417 includes a variable resistor 417A whose resistance value varies according to the rotation amount (rotation angle) of the operation dial 416A and a resistance according to the rotation amount (rotation angle) of the operation dial 416B. And a variable resistor 417B whose value varies. The operation amount detection unit 417 is connected to the power supply circuit 412 via the wiring 405. A predetermined DC voltage (for example, a maximum of 5 V at no load) generated from the commercial AC power supply by the power supply circuit 412 is applied to the operation amount detection unit 417 via the wiring 405.

A voltage (for example, a maximum of 5 V) corresponding to the resistance value of the variable resistor 417A is generated on the wiring (signal line) 418 connecting the operation amount detection unit 417 and the control device 420. On the other hand, a voltage (for example, a maximum of 5 V) corresponding to the resistance value of the variable resistor 417B is generated in the wiring (signal line) 419 connecting the operation amount detection unit 417 and the control device 420. In this way, the operation amount detection unit 417 generates a signal voltage corresponding to each operation amount of the operation dials 416A and 416B.

In addition, it can replace with the operation dials 416A and 416B and a slide bar is applicable. When the slide bar is applied, a voltage (signal) corresponding to the movement amount instead of the rotation amount is generated by the operation amount detection unit 417. Further, the operation amount detector 417 outputs a voltage corresponding to the variable resistance value as a control signal. Instead, a rotary encoder that detects the rotation amount (rotation angle) of the operation dials 416A and 416B may be provided, and a pulse indicating the rotation amount of the rotary encoder may be input to the control device 420. In this case, installation of an analog / digital converter for converting a voltage into a digital value as described later can be omitted.

The control device 420 is a control circuit that combines an analog / digital converter (A / D converter), a microcomputer (microcomputer: MP), a register, a timer, a counter, and the like. As the microcomputer, for example, a microprocessor with a built-in memory whose master clock operates at an operating frequency (for example, 4 MHz) from a crystal oscillator (not shown) can be applied. However, it is not limited to this. Further, the microcomputer loads an operation program recorded in a built-in ROM (Read Only Memory) (not shown) into a RAM (Random Access Memory) (not shown), and executes processing according to the program.

The A / D converter of the control device 420 outputs a digital value of the voltage generated on the signal line 418, and the digital value is set in a register (not shown). The A / D converter outputs a digital value of the voltage generated on the signal line 419, and the digital value is set in a register (not shown). The timer and counter included in the control device 420 are driven by a ceramic oscillator 421 that oscillates at a desired self-excited oscillation frequency (for example, 1 MHz), and wiring 424 connecting the control device 420 and the drive logic circuit 431. From 425, a complementary pulse is self-excited and output at a preset timing. For example, the complementary pulse is set in advance so that the repetition frequency becomes a predetermined frequency.

The microcomputer of the control device 420 performs control pulse generation processing for generating a control pulse (control signal) according to the digital value (the operation amount of the operation dials 416A and 416B) set in each register, and drives the generated pulse to drive logic. Supply (output) to the circuit 431. Note that pulses (control signals) generated by the microcomputer are supplied to the drive logic circuit 431 through the wirings 424 and 425.

The drive logic circuit 431 receives pulses (control signals) supplied from the wirings 424 and 425, and controls on / off operations (switching operations) of the transistors (switching elements) TR1 to TR4 according to the control signals. That is, the control circuit 431 turns off the transistors TR1 to TR4 when there is no pulse input from the wirings 424 and 425. On the other hand, while the positive pulse from the wiring 424 is input, the control circuit 431 turns on the transistors TR1 and TR4 while turning off the transistors TR2 and TR3. As a result, a direct current supplied from the power supply circuit 412 through the wiring 414 flows through the transistor TR1 to the power supply line 401a and is consumed for lighting the first LED element 1031. Thereafter, the current flows through the power supply line 401b and the transistor TR4 to the wiring 415 (grounded).

On the other hand, while the negative pulse from the wiring 425 is input, the drive logic circuit 431 turns on the transistors TR1 and TR4 while turning on the transistors TR2 and TR3. Thus, a direct current supplied from the power supply circuit 412 through the wiring 414 flows through the transistor TR2 to the wiring 401b and is consumed for lighting the second LED element 1032. Thereafter, the current flows through the wiring 401a and the transistor TR3 to the wiring 415 (grounded).

Therefore, the two-terminal LED light emitting device 10 is alternately supplied with a positive drive current and a negative drive current, which are similar to the pulse (control signal) output from the control device 420. In other words, alternating currents having different polarities are supplied as drive currents to the first LED element 1031 and the second LED element 1032.

FIG. 14 is a waveform explanatory diagram of the drive current supplied to the two-terminal LED light-emitting device 10 when performing luminance adjustment. In the present embodiment, in one cycle (period T0), the driving device 430 outputs a positive pulse during a period T1 during which a positive control signal is supplied and outputs a negative pulse during a period T2 during which a negative control signal is supplied. To do. When the operation dial 416A for dimming is operated, the microcomputer in the control device 420 adjusts the duty ratio by performing pulse width modulation (PWM) control.

Here, the average current supplied to the first LED element 1031 and the second LED element 1032 in the two-terminal LED light-emitting device 10 depends on the ON time of the pulse. That is, the average current value of the drive current supplied to the LED elements 1031 and 1032 in one cycle increases as the ON time of the positive and negative pulses increases. On the contrary, the average current value supplied to each LED element 1031 and LED element 1032 of the two-terminal LED light emitting device 10 becomes smaller as the duty ratio becomes smaller and the pulse ON time becomes smaller.

FIG. 14A shows a pulse when the duty ratio is 1. FIG. In this case, one pulse is output in each of the positive and negative pulse supply periods T1 and T2. FIG. 14B shows a state in which the duty ratio in the periods T1 and T2 is lowered as compared with the state shown in FIG. 14A by PWM control of the microcomputer. By changing the duty ratio, a plurality of positive and negative pulses are supplied. Further, FIG. 14 (c) shows a state where the duty ratio is further lowered than the state shown in FIG. 14 (b). In this case, the pulse widths t1 and t2 of the positive and negative pulses are further reduced as compared with the state shown in FIG.

The examples shown in FIGS. 14A to 14C show a state in which the operation dial 416A for dimming is sequentially operated so as to decrease (decrease) the luminance (light emission amount) of the two-terminal LED light-emitting device 10. As described above, when the operation dial 416A is operated, the microcomputer of the control device 420 decreases the duty ratio by PWM control, so that the pulse ON times t1 and t2 are shortened. As a result, the average current supplied to each parallel LED element group 103 of the two-terminal LED light emitting device 10 decreases, and the brightness of the output light output from each parallel LED element group 103 decreases (the amount of light emission decreases). However, the ratio of the pulse on-time t1, t2 in one cycle (positive half cycle period T1 and negative half cycle period T2) does not change here. Thereby, the brightness | luminance (light emission amount) of output light can be increased / decreased, without changing the chromaticity (hue, color temperature) of the 2 terminal LED light-emitting device 10. FIG.

FIG. 15 is a waveform explanatory diagram of the drive current supplied to the two-terminal LED light-emitting device 10 when performing chromaticity adjustment. FIGS. 15A to 15C show the pulse states when the operation dial 416B is operated. When the operation dial 416B is operated, the microcomputer of the control device 420 changes the number of positive and negative pulses in one cycle (period T0) without changing the pulse width at that time. In FIG. 15A, the pulse widths t1 and t2 in the positive and negative half cycles are the same, and the ratio of the pulse on-time in the positive and negative half cycles is 4: 3.

On the other hand, in FIG. 15B, the ratio of the pulse ON time in the positive and negative half cycles is changed to 3: 4. Further, in FIG. 15C, the ratio of the pulse ON time in the positive and negative half cycles is changed to 2: 5. By changing the ratio of the pulse ON time in such positive and negative cycles, the ratio of the lighting times of the first LED element 1031 and the second LED element 1032 in one cycle varies. As a result, the chromaticity (hue and color temperature) of the combined light emitted when each of the first LED element 1031 and the second LED element 1032 is turned on is changed.

The repetition frequency T0 (self-excited oscillation frequency) for outputting the positive and negative pulses described above can be determined between 30 Hz and 50 kHz, for example, from the viewpoint of human eye sensitivity, prevention of switching loss, and noise generation. Preferably, it is 50 Hz to 400 Hz. More preferably, it is 50 or 60 Hz to 120 Hz. The self-excited oscillation frequency can be determined independently from the commercial power supply frequency, but does not prevent the selection of the same frequency as the commercial power supply frequency.

Note that as shown in FIG. 13, the control circuit 413 in this embodiment is provided with integrating circuits 450 and 440. The integration circuit 450 feeds back a voltage proportional to the average value of the positive current for driving the first LED element 1031 to the control device 420, and the integration circuit 440 is a negative voltage for driving the second LED element 1032. A voltage proportional to the average value of the current is fed back to the control device 420. The control device 420 observes the feedback voltage of the integrating circuits 440 and 450 using an A / D converter and uses it for generating a control signal (pulse).

Hereinafter, an operation example of the light control device Dm will be described. When the main power switch 411 (see FIG. 12) is closed, rectification and voltage conversion operations are performed by the power supply circuit 412, and DC power is supplied to the control circuit 413. The microcomputer of the control device 420 starts an initialization operation by a known method, loads an operation program recorded in a built-in ROM (Read Only Memory) (not shown) into a RAM (Random Access Memory) (not shown), and follows the program. Process.

When adjusting the luminance of the two-terminal LED light emitting device 10, for example, the following operations and operations of the light control device 410 are performed. For example, when the user (user) turns the operation dial (operation knob) 416A to the right, for example, and sets the luminance (light emission amount) of the illumination to the maximum, a DC voltage of maximum 5.0 volts is generated on the signal line 418. To do. The control device 420 reads the voltage generated on the signal line 418 by converting it into a digital signal with a built-in A / D converter, and controls the drive logic circuit 431 of the drive circuit 430 via the signal lines 424 and 425. give. The drive logic circuit 431 drives the drive circuit (H-type bridge) 432 according to the control signal. At that time, the drive circuit 432 is driven at 50 Hz which is a preset self-oscillation frequency.

The control signal waveform at this time is as shown in FIG. 14A, and during the time t1, which is the ON time of the positive pulse (control signal), a positive current flows through the feeder line 401a and emits light from the two-terminal LED. The first LED element 1031 in the device 10 is turned on. On the other hand, during a time t2, which is the ON time of a negative pulse (control signal), a negative current flows through the power supply line 401b to light the second LED element 1032 in the two-terminal LED light emitting device 10. Then, since an alternating current of approximately 50 Hz is passed through the power supply line 401, the first LED element 1031 and the second LED element 1032 in the two-terminal LED light emitting device 10 are alternately lit.

Here, the ratio of the current flowing at time t1 (individual current) and the current flowing at time t2 (individual current) is generated by the first LED element 1031 and the second LED element 1032 in the two-terminal LED light emitting device 10. It will dominate the chromaticity of the combined light. In the state shown in FIG. 10A, since the lighting time of the first LED element 1031 having a high color temperature is longer than the lighting time of the second LED element 1032, the emission color of the two-terminal LED light emitting device 10 is slightly bluish. The color is white.

On the other hand, when the user turns the operation dial (dimming knob) 416A to the left and sets the illumination brightness to the median value, a DC voltage of about 2.5 volts is generated on the signal line 418. . In this case, the microcomputer of the control device 420 converts the voltage into a digital signal and reads it with a built-in A / D converter, controls the driving of the driving device 430, and supplies an alternating current to the LED lighting system LS. The pulse waveform at this time is in the state shown in FIG. That is, the ratio of the on time of the positive pulse in the period T1 and the on time of the negative pulse in the period T2 does not change, but since the duty ratio is reduced, one pulse at the maximum luminance has a plurality of pulse groups. It becomes. Here, the pulse width of the positive pulse and the pulse width of the negative pulse are the same. Accordingly, since the average current is smaller than that at the maximum luminance, the luminance of the output light from the first LED element 1031 and the second LED element 1032 in the two-terminal LED light emitting device 10 is lowered.

After that, the user further turns the operation dial (dimming knob) 416A leftward to set the illumination brightness to the minimum value. Then, the signal line 418 generates a DC voltage of about 0.5 volts. In this case, the microcomputer of the control device 420 converts the voltage value by the A / D converter and reads it, and controls the driving device 430 according to the voltage value. That is, as shown in FIG. 14C, the control device 420 further decreases the duty ratio of positive and negative pulses in the periods T1 and T2. As a result, the ratio of the on time of the positive pulse in the period T1 to the on time of the negative pulse in the period T2 does not change, and the pulse width of each pulse is further reduced. Thereby, since the average current is further reduced as compared with the case of the central luminance, both the output light from the first LED element 1031 and the second LED element 1032 in the two-terminal LED light emitting device 10 has the darkest luminance.

Next, a user (user) operation and an operation example of the light control device Dm when adjusting the chromaticity (hue, color temperature) of the two-terminal LED light emitting device 10 will be described. As described above, the current waveform shown in FIG. 14B is slightly bluish white because the average current for the first LED element 1031 is large for the second LED element 1032. Here, a case where the user intends to change from a state in which the current waveform shown in FIG. 14B is supplied to the two-terminal LED light emitting device 10 to a slightly reddish white color with a low Kelvin temperature will be described. In this case, the user rotates the operation dial (toning knob) 416B to the left (counterclockwise). Then, the DC voltage (for example, about 4 volts) generated in the signal line 419 is reduced to, for example, about 3.0 volts.

The microcomputer of the control device 420 reads the digital value of the DC voltage of the signal line 419 converted by the A / D converter, and changes the pulse waveform for controlling the driving device 430. For example, the microcomputer of the control device 420 changes the pulse waveform supplied to the drive logic circuit 431 of the drive device 430 from the state shown in FIG. 14B to the state shown in FIG. That is, in the state shown in FIG. 14B, the microcomputer sets the ratio of the ON time between the positive current (pulse) and the negative current (pulse), which was 5: 2, to 4 as shown in FIG. : Change to 3. As a result, the average current supplied to the first LED element 1031 decreases and the average current supplied to the second LED element 1032 increases. As a result, the emission color of the two-terminal LED light-emitting device 10, that is, the color temperature, is slightly lowered and presents a reddish white. At that time, the ratio of the on-time of the pulse in the positive and negative cycles changes, but the total value (total value of the average current) of the pulses in each of the positive and negative cycles does not change, so the luminance of the two-terminal LED light emitting device 10 changes. do not do.

After that, the user rotates the operation dial (chromaticity knob) 416B to the left (counterclockwise) to the limit in order to change the color temperature to the reddish white having the lowest color temperature. Then, the DC voltage of the signal line 419, which was about 3.0 volts, decreases to about 1.0 volts. When the microcomputer of the control device 420 detects the DC voltage of the digitally converted signal line 419, the microcomputer changes the control signal (pulse) for driving the full bridge driver 250 via the drive logic circuit 220. That is, the microcomputer gives a control signal to the driving device 430 so that the waveform of the current flowing through the power supply line 401a changes from FIG. 15 (a) to FIG. 15 (c). As a result, the average current of the first LED element 1031 further decreases, while the average current of the second LED element 1032 further increases. As a result, the color temperature of the two-terminal LED light-emitting device 10 is further lowered to exhibit a strong reddish white color. At this time, the overall luminance of the two-terminal LED light emitting device 10 does not change.

As described above, according to the LED lighting system LS according to the present embodiment, alternating current from an alternating current power source such as a commercial power source is converted into direct current, and alternating current (period) of a desired frequency based on the self-excited oscillation frequency is converted from the direct current. (Positive and negative currents supplied every T0) are generated and supplied as drive currents to the first LED element 1031 and the second LED element 1032 in the two-terminal LED light emitting device 10, respectively. Thereby, the freedom degree of design of the light control apparatus Dm can be raised. Further, according to the LED lighting system LS according to the present embodiment, the luminance (brightness) can be adjusted without changing the chromaticity (hue, color temperature) of the combined light output from the two-terminal LED light emitting device 10. Further, it is possible to adjust chromaticity (hue, color temperature) without changing luminance (lightness).

The preferred embodiments of the present invention have been described above, but various modifications can be made to the above embodiments without departing from the spirit of the present invention. For example, the transistors shown in the drawings of the above embodiments may be bipolar transistors or may be replaced with field effect transistors (FETs). In addition, the two-terminal LED light-emitting device, the light control device, and the LED lighting system (device) according to the present invention are not limited to the embodiments, and can include combinations thereof as much as possible.

DESCRIPTION OF SYMBOLS 1 ... AC power supply input terminal 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G ... Light emitting device 101, 102 ... Terminal 103, 103A ... Parallel LED element group 1031 ... No. One LED element 1032 ... second LED element 104 ... protection circuit 20 ... constant current circuit 20A ... first constant current circuit unit 20B ... second constant current circuit unit 30 ... Triac 40 ... Trigger diode 50 ... Time constant circuit 70 ... Hysteresis elimination circuit

Claims (4)

1. A parallel LED element group formed by connecting a first LED element and a second LED element having a light emission wavelength range different from that of the first LED element in reverse polar parallel;
   A two-terminal protection circuit including two Zener diodes connected in series with anode sharing or cathode sharing,
   The two-terminal protection circuit is a two-terminal LED light-emitting device connected in parallel to the plurality of parallel LED element groups connected in series.
2. The two-terminal LED light-emitting device according to claim 1, wherein the first LED elements are all connected to have the same polarity, and the second LED elements are all connected to have the same polarity. .
3. The two-terminal LED light emitting device according to claim 1 or 2, further comprising constant current means for supplying a constant current to each of the parallel LED element groups.
4. An LED lighting apparatus comprising the two-terminal LED light-emitting device according to any one of claims 1 to 3.

Images