JPH1168161A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain stable luminance, high reliability and high efficiency by installing a smoothing circuit which smoothes a pulse current obtained by switching operation of a switching regulator and supplies the current to a light- emitting unit. SOLUTION: Switching operation is started by inputting a DC voltage from a DC current 1 to an input terminal Vin of a switching regulator 5, and switching between a first switching terminal Vsc and a second switching terminal E is performed at a frequency, corresponding to a voltage inputted in a feedback terminal Vfb. Thereby, a current flowing into a coil 6 flows to the first switching terminal Vsc of the switching regulator 5 when a switch is turned on, and the current flowing in a coil 6 flows into a diode 7, when the switch is turned off. A pulse current obtained by the switching operation of the switching regulator 5 is smoothed, and a DC current obtained is supplied to a light-emitting unit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device comprising a plurality of light emitting diodes and a lighting circuit for lighting the light emitting diodes, and more particularly to a light emitting device with improved performance of the lighting circuit.

[0002]

2. Description of the Related Art Conventionally, in a light emitting device such as an illuminator, a sign, or the like, in which a large number of light emitting diodes are arranged, as shown in FIG. 6, a large number of light emitting diodes (25) are connected in series to emit light. In order to constitute the unit (24) and to light these light emitting diodes (25), a DC power supply (22)
The current from the light-emitting unit (24) is limited by the resistor (23).
Has been provided.

[0003]

In the conventional light emitting device, when the resistance value of the current limiting resistor (23) is set low, the light emitting diode (25) due to a voltage fluctuation of the DC power supply (22) or a temperature change. Due to the fluctuation of the voltage drop, the current flowing through the circuit greatly changes, and as a result, there arises a problem that a sufficient light emission luminance cannot be obtained and the light emitting diode (25) is overloaded and reliability is reduced. . Therefore, conventionally, the above-described problem is solved by setting the resistance value of the resistor (23) to a relatively high value, for example, a resistance value at which a voltage drop substantially equal to the voltage drop generated at the light emitting diode (25) occurs. Was. However, the efficiency is greatly reduced due to the voltage drop in the resistor (23).

An object of the present invention is to provide a light-emitting device that can obtain stable luminance and high reliability and high efficiency.

[0005]

According to the present invention, there is provided a light emitting device comprising:
The light emitting unit includes a light emitting unit in which a plurality of light emitting diodes are arranged and these light emitting diodes are connected to each other, and a lighting circuit that receives supply of DC power from a DC power supply and simultaneously lights the light emitting diodes of the light emitting unit.
Here, the lighting circuit receives a DC power from a DC power supply and performs a switching operation according to a magnitude of a current flowing through the light emitting unit, and smoothes a pulse current obtained by the switching operation of the switching regulator to a DC. And a smoothing circuit for supplying the light to the light emitting unit.

In the light emitting device of the present invention, the switching regulator and the smoothing circuit constitute a constant current circuit. That is, when the current flowing through the light emitting unit decreases, for example, the switching frequency of the switching regulator increases, and a pulse current having a larger duty ratio is output, and as a result, the current supplied to the light emitting unit increases. Conversely, when the current flowing through the light emitting unit increases, the switching frequency of the switching regulator decreases, and a pulse current having a smaller duty ratio is output, and as a result, the current supplied to the light emitting unit decreases. In this way, the current supplied to the light emitting unit is maintained at a predetermined target value.

In the light-emitting device according to the present invention in which a plurality of light-emitting diodes (12) are connected in series to each other to form a light-emitting unit (9), a lighting circuit is connected to a positive line (2) extending from a DC power supply (1). A connected input terminal Vin, a feedback terminal Vfb to which a voltage at a predetermined current adjustment point is supplied, and first and second switching terminals Vsc that perform switching between each other according to the voltage at the predetermined current adjustment point. , E, and the second switching terminal E connects the switching regulator (5) connected to the negative line (3) to the first switching terminal Vsc of the positive line (2) and the switching regulator (5). A coil (6) interposed in a line to be connected, and a line connecting one end of the coil (6) on the switching regulator (5) side and the positive terminal of the light emitting unit (9) to each other, the forward direction is the light emitting unit (9) side. To Diode intervening Te
(7), a capacitor (8) interposed in a line connecting the one end of the diode (7) on the light emitting unit (9) side and the negative line (3), and a negative terminal of the light emitting unit (9). Side track (3)
And a resistor (10) interposed in a line connecting the light emitting unit (9) and the light emitting unit (9) and a middle point of the resistor (10) as a current adjusting point as a feedback terminal Vfb of the switching regulator (5).
It is connected to the.

The light emitting device according to the present invention has a circuit configuration when the output voltage of the DC power supply (1) is lower than the voltage of the capacitor (8) (step-up type).
(5) Starts a switching operation by receiving an input voltage from the DC power supply (1) at the input terminal Vin, for example, according to the current adjustment point, that is, the voltage at the midpoint of the light emitting unit (9) and the resistor (10). At this frequency, switching between the first switching terminal Vsc and the second switching terminal E is performed. For example, when the voltage at the current adjustment point decreases, the frequency increases, and when the voltage at the current adjustment point increases, the frequency decreases. With the switching operation of the switching regulator (5), the current flowing from the DC power supply through the coil (6) flows to the first switching terminal Vsc of the switching regulator (5) when the switch is on, and when the switch is off. Is a diode
Flow toward (7). In this process, the electromotive force of the coil (6) is stored in the capacitor (8) via the diode (7). The pulse current obtained by the switching operation of the switching regulator (5) is smoothed by the smoothing action of the coil (6) and the capacitor (8),
The resulting DC current is supplied to the light emitting unit. When the current flowing through the light emitting unit (9) fluctuates for some reason, the current fluctuation becomes a voltage fluctuation at the current adjustment point by the resistor (10), and the switching operation of the switching regulator (5) is controlled according to the voltage fluctuation. And
The current flowing through the light emitting unit (9) is maintained at a predetermined constant value.

On the other hand, in a step-down light emitting device in which the output voltage of the DC power supply (1) is higher than the voltage of the capacitor (8), the lighting circuit is connected to the positive line (2) extending from the DC power supply (1). Input terminal Vin, a feedback terminal Vfb to which a voltage at a predetermined current adjustment point is supplied, and first and second switching terminals Vsc and E that perform switching between each other according to the voltage at the predetermined current adjustment point. A first switching terminal Vsc includes a switching regulator (5) connected to the positive line (2) and a switching regulator.
A coil (6a) interposed in a line connecting the second switching terminal point E of (5) and the positive terminal of the light emitting unit (9) to each other.
A diode (7a) interposed in a line connecting the second switching terminal E of the switching regulator (5) and the negative line (3) to each other in the forward direction toward the second switching terminal E; and a coil (6a). ), A capacitor interposed in a line connecting one end of the light emitting unit (9) side and the negative line (3) to each other.
(8) and a resistor (10) interposed in a line connecting the negative terminal of the light emitting unit (9) and the negative line (3) to each other, and a midpoint between the light emitting unit (9) and the resistor (10). Is connected to the feedback terminal Vfb of the switching regulator (5) as a current adjustment point.

In the light emitting device according to the present invention, the switching operation of the switching regulator (5) causes
When the switch is on, the current flowing from the DC power supply to the first switching terminal Vsc of the switching regulator (5) via the positive line (2) flows from the second switching terminal E to the coil (6a), and the coil (6a) The capacitor (8) is charged by the electromotive force. On the other hand, when the switch is off, the power stored in the capacitor (8) is discharged. In this process, a DC current obtained by the smoothing action of the coil (6a) and the capacitor (8) is supplied to the light emitting unit.

A plurality of light emitting diodes (20) are connected in series with each other to form a diode array (18).
In the light emitting device of the present invention in which a plurality of diode arrays (18) are connected in parallel with each other to form a light emitting unit (9),
The lighting circuit includes an input terminal Vin connected to a positive line (2) extending from the DC power supply (1), a feedback terminal Vfb supplied with a voltage at a predetermined current adjustment point, and a voltage at a predetermined current adjustment point. Switching between each other according to the first
And a second switching terminal Vsc, E, and the second switching terminal E is a switching regulator (5) connected to the negative line (3), and a second switching terminal (E) of the positive line (2) and the switching regulator (5). A coil interposed in each of a plurality of parallel lines connecting one switching terminal Vsc to each other
(14) and switching regulator (5) for each coil (14)
The current flowing through each coil (14) is supplied to the first switching terminal Vsc of the switching regulator (5) by interposing each parallel line connecting one end of the switching regulator (5) and the first switching terminal Vsc of the switching regulator (5) to each other. And a current control element for flowing toward the switching regulator (5) side of each coil (14) and a positive terminal of each diode array (18) of the light emitting unit (9). A diode (16) interposed in the forward direction toward the diode array (18), and a line connecting one end of each diode (16) on the diode array (18) side and the negative line (3) to each other. Interposed capacitors (17) and each diode array
(18) and a resistor (19) interposed in each of the lines connecting the negative line (3) to each other, and the middle point of at least one diode array (18) and the resistor (19) is It is connected to the feedback terminal Vfb of the switching regulator (5) as an adjustment point.

Here, the current control element is constituted by a diode (15) or a transistor (21) whose forward direction is directed to the switching regulator (5) side.

The light emitting device according to the present invention has a circuit configuration when the output voltage of the DC power supply (1) is lower than the voltage of the capacitor (17) (step-up type).
Since the first switching terminal Vsc of (5) is distributed and connected to each coil (14) via a plurality of current control elements, an electromotive force of the same magnitude is generated in each coil (14), and each coil (14) 14)
Is stored in each capacitor (17) via each diode (16). Then, the pulse current obtained by the switching operation of the switching regulator (5) is smoothed by the smoothing action exerted by the coil (14) and the capacitor (17) in series with each other, and the DC current obtained by this is reduced. It is supplied to each diode array (18) of the light emitting unit (9). When the current flowing through each diode array (18) fluctuates for some reason, the current fluctuation is caused by the resistance.
The voltage fluctuation at the current adjustment point is caused by (19), and the switching operation of the switching regulator (5) is controlled according to the voltage fluctuation, and the current flowing through each diode array (18) is maintained at a predetermined constant value.

On the other hand, in a step-down light emitting device in which the output voltage of the DC power supply (1) is higher than the voltage of the capacitor (17), the lighting circuit is connected to the positive line (2) extending from the DC power supply (1). Input terminal Vin, a feedback terminal Vfb to which a voltage at a predetermined current adjustment point is supplied, and first and second switching terminals Vsc, E which perform switching between each other according to the voltage at the predetermined current adjustment point. A first switching terminal Vsc is connected to the positive line (2), a switching regulator (5), and a switching regulator.
A current is distributed to each diode array (18) via a line connecting the second switching terminal E of (5) and the positive terminal of each diode array (18) of the light emitting unit (9) to each other. Control elements, a coil (14a) interposed in each of the lines connecting the current control elements and the positive terminal of each diode array (18) to each other, and a switching regulator (5) for each coil (14a) The forward end of each of the parallel lines connecting one end of the negative side line and the negative side line (3) to the coil (14
a) A diode (16a) interposed toward the a) side, one end of each diode (14a) on the diode array (18) side and a negative line.
(3) Capacitors interposed in each of the lines connecting each other
(17), the negative terminal and the negative line of each diode array (18)
A resistor (19) interposed in each of the lines connecting (3) to each other, wherein at least one diode array (18) and a resistor
The middle point of (19) is connected to the feedback terminal Vfb of the switching regulator (5) as a current adjustment point.

In the above light emitting device of the present invention, the switching operation of the switching regulator (5) causes
When the switch is on, the DC power supply (1) to the positive line (2)
The current flowing into the first switching terminal Vsc of the switching regulator (5) flows from the second switching terminal E to the current control element, is distributed to each coil (14a), and is equal in magnitude to each coil (14a). An electromotive force is generated, and each capacitor (17) is charged by the electromotive force.
On the other hand, when the switch is off, the power stored in each capacitor (17) is discharged. In this process, the coil (14
DC current obtained by a) and the smoothing action of the capacitor (17) is supplied to the light emitting unit.

In another specific configuration, a plurality of light emitting diodes constituting the light emitting unit (9) are provided with a zener voltage higher than a forward voltage of the unit in units of one or more light emitting diodes. Zener diodes are connected in parallel. In the specific configuration,
When one of the light emitting diodes in the light emitting unit (9) fails in the open mode, the light emission stops in the unit to which the light emitting diode belongs. However, through the Zener diode connected in parallel to the unit, Since the electrical connection is ensured, the energization of the majority of normal light emitting diodes belonging to other units is continued, and these light emitting diodes maintain the light emitting state. Therefore, sufficient light emission luminance can be obtained as a whole.

[0017]

According to the light emitting device of the present invention, since the light emitting diode of the light emitting unit is driven at a constant current, there is no need to provide a current limiting resistor. Therefore, the efficiency does not decrease due to the voltage drop, and the high efficiency is maintained.
Further, even if a voltage fluctuation of the DC power supply or a fluctuation of a voltage drop of the light emitting diode due to a temperature change occurs, the current flowing through the light emitting diode is maintained at a predetermined constant value, and an appropriate load state is maintained. High emission luminance and high reliability can be obtained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. First Embodiment A light-emitting device shown in FIG. 1 comprises a plurality of light-emitting diodes (12) connected in series to each other to form a light-emitting unit (9), and comprises an output voltage of a DC power supply (1) such as a battery. Has a step-up circuit configuration lower than a voltage stored in a capacitor (8) described later. Each light emitting diode (12) has
A zener diode (13) having a zener voltage slightly higher than the forward voltage of the light emitting diode (12) is connected in parallel.

A positive line (2) and a negative line (3) extend from a positive terminal and a negative terminal of a DC power supply (1) such as a battery, respectively, and a capacitor (4) is interposed between the two lines. doing. Further, a switching regulator (5) is connected between the positive line (2) and the negative line (3). The switching regulator (5) includes an input terminal Vin connected to the positive line (2), a ground terminal Gnd connected to the negative line (3), and a feedback to which a voltage at a predetermined current adjustment point is supplied. Terminal Vfb and built-in switching transistor
The first and second switching terminals Vsc and E are connected to the collector and the emitter of (50).

The tip of the positive line (2) is connected to a first switching terminal Vsc of a switching regulator (5) via a coil (6). Switching regulator
The first switching terminal Vsc of (5) is connected to the negative terminal of the light emitting unit (9) via the diode (7), and the second switching terminal E is connected to the negative line (3). Further, one end of the diode (7) on the light emitting unit (9) side and the tip of the negative line (3) are connected to each other via a capacitor (8). Further, the negative terminal of the light emitting unit (9) is connected to the tip of the negative line (3) via a resistor (10). The midpoint of the light emitting unit (9) and the resistor (10) is connected to the feedback terminal Vfb of the switching regulator (5) via the feedback line (11).

In the above light emitting device, the DC voltage supplied from the DC power supply (1) is a switching regulator.
(5) is input to the input terminal Vin, the switching regulator (5) starts the switching operation, and the first switching terminal Vsc and the second switching terminal are switched at a frequency corresponding to the magnitude of the voltage input to the feedback terminal Vfb. Switching between terminals E is performed. This allows the coil
The current flowing through (6) flows to the first switching terminal Vsc of the switching regulator (5) when the switch is on, and flows toward the diode (7) when the switch is off. In this process, the electromotive force of the coil (6) is stored in the capacitor (8) via the diode (7). Then, the pulse current obtained by the switching operation of the switching regulator (5) is smoothed by the smoothing action exerted by the coil (6) and the capacitor (8), and the DC current obtained by this is converted into the light emitting unit (9). It is supplied to.

When the current flowing through the light emitting unit (9) fluctuates for some reason, the current fluctuation becomes a voltage fluctuation at the midpoint between the light emitting unit (9) and the resistor (10), and the voltage fluctuation is reflected on the feedback line (11). Is input to the feedback terminal Vfb of the switching regulator (5). As a result, the switching operation of the switching regulator (5) is controlled, and the current flowing through the light emitting unit (9) is maintained at a predetermined constant value.

According to the above light emitting device, the light emitting unit (9)
Since each of the light emitting diodes (12) is driven by a constant current, there is no need to provide a current limiting resistor as in the prior art, and the resistor for voltage detection (10) requires a low resistance value. The efficiency does not decrease due to the descent, and high efficiency is obtained. Even if the voltage of the DC power supply (1) fluctuates and the voltage of the light emitting diode (12) fluctuates due to a temperature change, the light emitting diode (12) is driven at a constant current. Reliability is obtained. Furthermore, even if one light emitting diode (12) fails in the open mode, the Zener diode (13) connected in parallel to the light emitting diode (12) has both ends of the light emitting diode (12). Since the light emitting diode is kept in a conductive state, a current is supplied to the other light emitting diodes (12), and a sufficient light emission luminance can be obtained as a whole.

Second Embodiment On the other hand, the light emitting device shown in FIG. 2 has a step-down circuit configuration in which the output voltage of a DC power supply (1) is higher than the voltage stored in a capacitor (8), and a switching regulator (5)
A coil (6a) is interposed between the second switching terminal E and the light emitting unit (9), and a diode (7a) is interposed between the second switching terminal E and the negative line (3). , Is different from the light emitting device of the first embodiment.

In the above-mentioned light emitting device, when the switch is turned on in accordance with the switching operation of the switching regulator (5), the first switching of the switching regulator (5) from the DC power supply (1) via the positive line (2). Terminal V
The current flowing into the sc flows from the second switching terminal E to the coil (6a), and the capacitor is generated by the electromotive force of the coil (6a).
(8) is charged. On the other hand, when the switch is off, the power stored in the capacitor (8) is discharged. In this process, a DC current obtained by the smoothing action of the coil (6a) and the capacitor (8) is supplied to the light emitting unit (9).

Third Embodiment In the light emitting device shown in FIG. 3, a plurality of light emitting diodes (20) are connected in series with each other to form a diode array (18), and the plurality of diode arrays (18) are connected in parallel with each other. To form a light-emitting unit (9), which has a step-up circuit configuration. Positive line (2) and negative line extending from the positive terminal and negative terminal of DC power supply (1), respectively
The capacitor (4) and the switching regulator (5) are connected to (3) as in the first embodiment.

A plurality of coils (14) are provided at the tip of the positive line (2).
(14) (14) are connected in parallel, and each coil (14) is connected to the first of the switching regulator (5) via a diode (15).
It is connected to the switching terminal Vsc. In addition, coil (1
The midpoints of 4) and the diode (15) are connected to the positive terminal of each diode array (18) via a diode (16) whose forward direction is directed toward the diode array (18). Furthermore,
One end of each diode (16) on the diode array (18) side is connected to the negative line (3) via a capacitor (17). Further, the negative terminal of each diode array (18) is connected to the tip of the negative line (3) via a resistor (19). One diode array (1) in the light emitting unit (9)
The midpoint between 8) and the resistor (19) is connected to the feedback terminal Vfb of the switching regulator (5) via the feedback line (11).

In the above light emitting device, the DC voltage supplied from the DC power supply (1) is a switching regulator.
(5) is input to the input terminal Vin, the switching regulator (5) starts the switching operation, and the first switching terminal Vsc and the second switching terminal are switched at a frequency corresponding to the magnitude of the voltage input to the feedback terminal Vfb. Switching between terminals E is performed. Thus, the current flowing through each coil (14) flows to the first switching terminal Vsc of the switching regulator (5) when the switch is on, and flows toward the diode (16) when the switch is off. Here, since the first switching terminal Vsc of the switching regulator (5) is distributed and connected to each coil (14) via a plurality of diodes (15), an electromotive force of the same magnitude is applied to each coil (14). The generated electromotive force of each coil (14) is stored in each capacitor (17) via each diode (16).
Then, the pulse current obtained by the switching operation of the switching regulator (5) is smoothed by the smoothing action exerted by the coil (14) and the capacitor (17) in series with each other, and the DC current obtained by this is reduced. It is supplied to each diode array (18) of the light emitting unit (9).

When the current flowing through each diode array (18) fluctuates for some reason, the current fluctuation becomes a voltage fluctuation at the midpoint between the diode array (18) and the resistor (19). ) Is input to the feedback terminal Vfb of the switching regulator (5). As a result, the switching operation of the switching regulator (5) is controlled, and the current flowing through each diode array (18) is maintained at a predetermined constant value. Note that only the current adjustment point of one diode array (18) is fed back to the switching regulator (5) via the feedback line (11).
Fluctuations in the voltage drop of the light-emitting diodes (20) due to temperature changes have the same effect on any of the diode arrays (18). Therefore, even with feedback control based on one current adjustment point, all the diode arrays (18) are controlled. (18) It is possible to drive (18) and (18) with a constant current.

According to the above light emitting device, as in the first and second embodiments, each light emitting diode (20) of the light emitting unit (9) is used.
Is driven by constant current, so high efficiency is obtained and
Sufficient light emission luminance and high reliability can be obtained.

Incidentally, similarly to the first and second embodiments, it is possible to connect a Zener diode in parallel with the light emitting diode (20).
Open mode failure can be dealt with. or,
As shown in FIG. 5, a plurality of diodes (15), (15) and (15) for distributing and connecting the first switching terminal Vsc of the switching regulator (5) to the respective coils (14) are transistors as shown in FIG. Instead of (21), a buffering method using a plurality of transistors can be adopted.

Fourth Embodiment On the other hand, the light emitting device shown in FIG. 4 has a step-down type circuit configuration in which the output voltage of the DC power supply (1) is higher than the voltage stored in the capacitor (17). (5)
Between the second switching terminal E and the light emitting unit (9),
The third embodiment is that a plurality of diodes (15a) and a coil (14a) are interposed, and a diode (16a) is interposed between an input terminal of each coil (14a) and the negative line (3). It differs from the example light emitting device.

In the above light-emitting device, when the switch is turned on with the switching operation of the switching regulator (5), the first switching of the switching regulator (5) from the DC power supply (1) via the positive line (2). Terminal V
The current flowing into the sc flows from the second switching terminal E into each diode (15a) and is distributed to each coil (14a). As a result, an electromotive force of the same magnitude is generated in each coil (14a), and each capacitor (17) is charged by the electromotive force. On the other hand, when the switch is off, the power stored in each capacitor (17) is discharged. In this process,
A direct current obtained by the smoothing action of the coil (14a) and the capacitor (17) is supplied to the light emitting unit (9).

The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, the DC power supply (1) can be configured by an AC-DC converter that converts AC power obtained from a commercial power system into DC.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a light emitting device according to the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the above.

FIG. 3 is a circuit diagram showing a third embodiment of the above.

FIG. 4 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 5 is a circuit diagram of another configuration example using a transistor as a current control element.

FIG. 6 is a circuit diagram of a conventional light emitting device.

[Explanation of symbols]

 (1) DC power supply (2) Positive line (3) Negative line (4) Capacitor (5) Switching regulator (6) Coil (7) Diode (8) Capacitor (9) Light emitting unit (10) Resistance (11) Feedback line (12) Light emitting diode (13) Zener diode

Claims (8)

[Claims] 1. A light emitting unit in which a plurality of light emitting diodes are arranged and these light emitting diodes are connected to each other, and a lighting circuit which receives supply of DC power from a DC power supply and simultaneously lights the light emitting diodes of the light emitting units. In the light emitting device configured, the lighting circuit includes a switching regulator that receives a DC power from a DC power supply and performs a switching operation according to the magnitude of a current flowing through the light emitting unit, and a pulse current obtained by the switching operation of the switching regulator. A light-emitting device comprising: 2. A light emitting unit in which a plurality of light emitting diodes are arranged and these light emitting diodes are connected to each other, and a lighting circuit which receives power supplied from a DC power supply (1) and simultaneously lights the light emitting diodes of the light emitting units. The light emitting unit (9) comprises:
The lighting circuit is configured by connecting a plurality of light emitting diodes (12) in series with each other. The lighting circuit includes an input terminal Vin connected to a positive line (2) extending from a DC power supply (1), and a voltage at a predetermined current adjustment point. Is provided, and first and second switching terminals Vsc, E are switched between each other according to the voltage at a predetermined current adjustment point, and the second switching terminal E is connected to the negative side line. A switching regulator (5) connected to (3), a coil (6) interposed in a line connecting the positive side line (2) and the first switching terminal Vsc of the switching regulator (5) to each other, and a coil (6). A line connecting one end of the switching regulator (5) side and the positive terminal of the light emitting unit (9) to each other,
A diode (7) interposed with the forward direction toward the light emitting unit (9); one end of the diode (7) on the light emitting unit (9) side and a negative line;
Capacitor (8) interposed in the line connecting (3) to each other
And a resistor (10) interposed in a line connecting the negative terminal of the light emitting unit (9) and the negative line (3) to each other.
A light emitting device in which the midpoint between (9) and the resistor (10) is connected to the feedback terminal Vfb of the switching regulator (5) as a current adjustment point. 3. A light-emitting unit in which a plurality of light-emitting diodes are arranged and these light-emitting diodes are connected to each other, and a lighting circuit for receiving power supplied from a DC power supply and lighting the light-emitting diodes of the light-emitting units simultaneously. The light emitting unit (9) comprises:
The lighting circuit is configured by connecting a plurality of light emitting diodes (12) in series with each other. The lighting circuit includes an input terminal Vin connected to a positive line (2) extending from a DC power supply (1), and a voltage at a predetermined current adjustment point. Is provided, and first and second switching terminals Vsc and E are switched between each other according to the voltage at a predetermined current adjustment point. The first switching terminal Vsc is connected to the positive line ( A switching regulator (5) connected to 2), a coil (6a) interposed in a line connecting the second switching terminal point E of the switching regulator (5) and the positive terminal of the light emitting unit (9) to each other; A diode (7) interposed in a line connecting the second switching terminal E of the regulator (5) and the negative line (3) to each other in a forward direction toward the second switching terminal E.
a), one end of the coil (6a) on the light emitting unit (9) side and the negative line (3)
And a resistor (10) interposed in a line connecting the negative terminal and the negative line (3) of the light emitting unit (9) to each other.
A light emitting device in which the midpoint between (9) and the resistor (10) is connected to the feedback terminal Vfb of the switching regulator (5) as a current adjustment point. 4. A light emitting unit in which a plurality of light emitting diodes are arranged and these light emitting diodes are connected to each other, and a lighting circuit which receives a DC power supply and simultaneously lights all the light emitting diodes of the light emitting unit. In the light emitting device, the light emitting unit (9) is configured by connecting a plurality of diode arrays (18) in parallel with each other,
Each diode array (18) is configured by connecting a plurality of light emitting diodes (20) in series with each other. The lighting circuit includes an input terminal Vin connected to a positive line (2) extending from a DC power supply (1), A feedback terminal Vfb to which a voltage at a predetermined current adjustment point is supplied, and first and second switching terminals Vsc and E for switching between each other according to the voltage at the predetermined current adjustment point; The switching terminal E includes a switching regulator (5) connected to the negative line (3) and a plurality of parallel lines connecting the positive line (2) and the first switching terminal Vsc of the switching regulator (5) to each other. Each of the coils (14) interposed in each of the parallel lines connecting one end of each coil (14) on the switching regulator (5) side and the first switching terminal Vsc of the switching regulator (5) to each other. Te, the current flowing through the respective coils (14) switching regulator (5)
A current control element for flowing toward the first switching terminal Vsc, and one end of each coil (14) on the switching regulator (5) side and a positive terminal of each diode array (18) of the light emitting unit (9). A diode (16) interposed in the forward direction toward the diode array (18) side, and one end of each diode (16) on the diode array (18) side and a negative line (3) are connected to each of the interconnected lines. A capacitor (17) interposed in each of the lines connecting to each other, and a resistor (19) interposed in each of the lines connecting the negative terminal of each diode array (18) and the negative line (3) to each other;
A light emitting device in which a middle point of at least one diode array (18) and a resistor (19) is connected to a feedback terminal Vfb of a switching regulator (5) as a current adjustment point. 5. The light emitting device according to claim 4, wherein the current control element is constituted by a diode (15) or a transistor (21) whose forward direction is directed to the switching regulator (5) side. 6. A light emitting unit in which a plurality of light emitting diodes are arranged and these light emitting diodes are connected to each other, and a lighting circuit which receives a DC power supply and simultaneously lights all the light emitting diodes of the light emitting unit. In the light emitting device, the light emitting unit (9) is configured by connecting a plurality of diode arrays (18) in parallel with each other,
Each diode array (18) is configured by connecting a plurality of light emitting diodes (20) in series with each other. The lighting circuit includes an input terminal Vin connected to a positive line (2) extending from a DC power supply (1), A feedback terminal Vfb to which a voltage at a predetermined current adjustment point is supplied, and first and second switching terminals Vsc and E for switching between each other according to the voltage at the predetermined current adjustment point; The switching terminal Vsc is connected to the switching regulator (5) connected to the positive line (2), the second switching terminal E of the switching regulator (5) and the positive terminal of each diode array (18) of the light emitting unit (9). A current control element for distributing a current to each diode array (18), and a current control element and a positive terminal of each diode array (18) are connected to each other via respective lines connecting the Coil (14a) interposed in each of the tracks
And a diode (16a) interposed in the forward direction toward the coil (14a) side of each of the parallel lines connecting one end of each coil (14a) on the switching regulator (5) side and the negative line (3) to each other. ), One end of each diode (14a) on the diode array (18) side and a capacitor (17) interposed in each of the lines connecting the negative line (3) to each other, and a negative terminal of each diode array (18). And a resistor (19) interposed in each of the lines connecting the negative line (3) to each other,
A light emitting device in which a middle point of at least one diode array (18) and a resistor (19) is connected to a feedback terminal Vfb of a switching regulator (5) as a current adjustment point. 7. The light emitting device according to claim 6, wherein the current control element is constituted by a diode (15a) or a transistor whose forward direction is directed toward the diode array (18). 8. A plurality of light emitting diodes constituting the light emitting unit (9) include a zener diode having a zener voltage higher than a forward voltage of the unit in units of one or more light emitting diodes. The light emitting device according to claim 1, wherein the light emitting device is connected in parallel to the light emitting device.