KR101336857B1 - Light emitting circuit - Google Patents

Abstract

The present disclosure provides a light emitting group having a plurality of PN-junction light emitting devices connected in series; Circuit elements related to control of power supplied to the light emitting group or control of light emission of the light emitting group; And an electrical element electrically connected to at least one of the plurality of PNJ light emitting elements, the electrical element forming an operating power supply by a voltage drop by the at least one PNJ light emitting element and supplying the same to the circuit element; It relates to a light emitting circuit comprising a.

Description

 Light Emitting Circuit {LIGHT EMITTING CIRCUIT}

The present disclosure relates generally to a light emitting circuit, and more particularly, to a light emitting circuit for supplying operating power of a circuit element by using a voltage drop caused by the light emitting element.

Herein, the background art relating to the present disclosure is provided, and these are not necessarily meant to be known arts.

Recently, in the lighting industry, various other lighting devices such as incandescent lamps and fluorescent lamps have been replaced by LED (Light Emitting Diode) lighting devices, and technological development of a constant current power supply device for stably supplying power to LED lighting devices has become prominent .

The LED drive method can be classified into DC drive, AC drive, and PWM drive.

DC drive requires an AC / DC converter that converts the AC voltage to a low DC voltage. This additional circuit configuration complicates the drive circuitry, introduces additional power consumption, and is a major cause of increasing the cost of the product and lowering the overall efficiency.

In order to solve the above-mentioned problems of DC driving, a power supply device of SMPS (Switching Mode Power Supply) type is used as shown in FIG. 1 as an example using a PWM driving method. The SMPS method is simple and fine control of temperature compensation and optical output control. However, since the AC (50Hz ~ 60Hz) is converted into DC and used, it requires high technology and the complication of circuit is complicated at commercial voltage have.

Accordingly, as a method for lowering the price of the LED driver, for example, as shown in FIG. 2, an AC direct drive type LED driver for directly driving an LED with an AC power source without using an SMPS is disclosed.

The AC direct LED driving method has an advantage that the LED can be driven by an AC power source using only a passive element without using a special active element. In this method, there is no need for a converter for converting AC power to DC power, so that miniaturization and cost reduction of parts can be achieved remarkably. In addition, the complexity of the circuit is reduced, and the maintenance cost due to the failure can be reduced.

On the other hand, the conventional AC direct drive type LED driver as shown in Figure 2 is to improve the efficiency and power factor by adjusting the number of LEDs to be emitted according to the input voltage using a switch circuit.

In the AC direct LED driving method, the input power is divided by using a plurality of resistors to obtain the operating power of the circuit elements related to the control of the switch circuit or the power source, thereby forming the operating power of the circuit elements. In the DC driving method, a plurality of devices were required to form an operating power source for driving circuit devices.

However, in order to obtain an operating power source, a large number of devices such as resistors are required. Accordingly, the loss of power increases, so that the efficiency is greatly reduced, and heat generation increases, which adversely affects the light emitting circuit.

This will be described later in the Specification for Implementation of the Invention.

SUMMARY OF THE INVENTION Herein, a general summary of the present disclosure is provided, which should not be construed as limiting the scope of the present disclosure. of its features).

According to one aspect of the present disclosure, there is provided an according to one aspect of the present disclosure; Circuit elements related to the control of the power supplied to the PEN junction light emitting element or the light emission of the PEN junction light emitting element; And an electric element for forming an electric energy from a voltage drop between a first position on a current path of the PN junction light emitting element and a second position having a lower potential than the first position, and supplying the electrical energy to an operating power source of the circuit element. A light emitting circuit is provided.

This will be described later in the Specification for Implementation of the Invention.

1 is a diagram showing an example of a PWM driving circuit,
2 is a view showing an example of an AC drive circuit not using an SMPS,
3 is a block diagram illustrating an example of a light emitting circuit according to the present disclosure;
4 is a circuit diagram illustrating an example of a light emitting circuit described in FIG. 3;
5 is a view for explaining examples of the electric element shown in FIG.
6 is a view for explaining a waveform of a voltage output from the electric element shown in FIG. 4;
7 is a view for explaining another example of a light emitting circuit according to the present disclosure;

The present disclosure will now be described in detail with reference to the accompanying drawing (s).

3 is a block diagram illustrating an example of a light emitting circuit according to the present disclosure.

The light emitting circuit 100 includes a rectifier circuit 120, a plurality of PN-junction light emitting devices 141, an electric device 170, and a circuit device 150.

The supplied power is rectified by the rectifier circuit 120 and supplied to the PJ junction 141. The power source is a power source whose voltage periodically rises and falls, for example, is supplied by an AC power source. The supplied alternating current is converted into pulse current by the rectifier circuit 120. When a current flows through the PJ light emitting element 141, the current may be constantly controlled by a constant current circuit (not shown).

The p-junction light-emitting device 141 is a typical example of a light emitting diode (LED), and may be an LD (Laser Diode) or the like. Hereinafter, the LED 141 will be described as an example. The LEDs 141 may be mounted on the printed circuit board to form one group or the LEDs 141 mounted on one printed circuit board may be grouped into a plurality of groups. For example, the plurality of LEDs 141 are connected in series.

The circuit element 150 is an element related to control of power supplied to the LED 141 or control of light emission of the LED 141. For example, the circuit device 150 may include a switch for turning on / off the LED 141, a switch control circuit for controlling the switch, or a microprocessor for controlling power or light emission. An operation power source is required for the operation of the circuit device 150, and the required voltage of the operation power source may be very small compared to the input voltage.

In the present disclosure, the operating power of the circuit device 150 is obtained from the electric device 170, rather than a direct voltage distribution method using a plurality of resistors.

The electric element 170 forms electrical energy from a voltage drop between the first position and the second position having a lower potential than the first position on the path of the current flowing through the LED 141 and supplies the electrical energy to the operating power of the circuit element. For example, an electrical device 170 may be connected to both ends of at least one of the plurality of LEDs 141, and a voltage drop generated by the LEDs 141 may be used to form an operating power supply of the circuit device 150. .

4 is a circuit diagram illustrating an example of the light emitting circuit 100 described with reference to FIG. 3. FIG. 5 is a view for explaining examples of the electric element 170 shown in FIG. 4.

4 illustrates a bridge rectifier circuit as an example of the rectifier circuit 120.

An example of the electric device 170 is shown a capacitor. Hereinafter, the same reference numerals are used for the capacitor 170 and the electric element 170. The capacitor 170 is electrically connected to the input terminal (first position) and the output terminal (second position) of the last two LEDs 141 in the arrangement of the PN-junction light emitting element 141 and is connected in parallel with the LEDs 141. Therefore, the capacitor 170 is charged by the voltage drop by the two LEDs 141. The magnitude of the operating voltage may be determined by adjusting the number of LEDs 141 to be included between the first and second positions according to the operating voltage required for the circuit device 150. For example, when a voltage drop of 3 V per LED 141 occurs, as shown in FIG. 5, an operating voltage of 6 V is formed by the capacitor 170 using two LEDs 141, or an LED 141 1. The operating voltage of 3V can be formed.

FIG. 6 is a diagram illustrating waveforms of voltages output from the electric element 170 shown in FIG. 4.

The capacitor 170 is electrically connected to the circuit element 150, and the capacitor 170 is charged and discharged as the input voltage changes, and supplies operating power to the circuit element 150. The current supplied to the LED 141 is provided in a pulse current, and thus the capacitor 170 is also charged and discharged according to the pulse current. The capacitor 170 operates as a filter and may filter the ripple of the pulse current to output an operating voltage having a waveform as shown in FIG. 6. Therefore, the operating power required for the circuit element 150 can be stably supplied.

Therefore, a plurality of resistors used to form an operating power source in the circuit device 150 are eliminated. As a result, the number of devices used in the light emitting circuit 100 is reduced, and heat generation that adversely affects the LED 141 is reduced. Power losses due to devices such as resistors are greatly reduced.

7 is a view for explaining another example of the light emitting circuit 300 according to the present disclosure.

The light emitting circuit 300 is grouped into a first group G1, a second group G2, and a third group G3 in which a plurality of LEDs 341 are connected in series, and the switches SW1, SW2, and the constant current circuit ( It is substantially the same as the light emitting circuit 100 described with reference to FIGS. 3 to 6 except for further including 330. Therefore, redundant description is omitted.

The number and arrangement of the LEDs 341 for each group may be changed according to the needs of the light emitting circuit 300. For example, in the first group G1, 11 LEDs 341 connected in series are in series, the second group G2 is 8 LEDs 341 in series, and the third group G3 is 11 LEDs 341 may be provided in series.

The constant current circuit 330 protects the light emitting circuit 300 by preventing overcurrent. The constant current circuit 330 is provided in each group or as shown in FIG. 7 so that the first group G1, the second group G2, and the third group G3 can use only one constant current circuit 330. It may be located in front of the first group (G1). For example, the constant current circuit 330 performs constant current control at 40 mA. Therefore, a total of 40 mA of current flows through the LED 341.

As described above, in order to improve the efficiency of the light emitting circuit 300, the light emission of each group is controlled using the switches SW1 and SW2.

The electric element 370 is electrically connected to a circuit element, and FIG. 7 illustrates a switch control circuit 350 as a circuit element that receives operating power from the electric element 370. For example, the switch control circuit 350 may include a variable resistor and a comparator.

The first switch SW1 and the second switch SW2 are turned on and off by signals sg1 and sg2 due to a comparison operation between the input voltage and the reference voltage of the comparator of the switch control circuit 350, and thus the first group G1. ), The path of the current flowing to the second group G2 and the third group G3 is changed. The on / off period of the first switch SW1 and the second switch SW2 is 120 Hz, for example.

The first switch SW1 is connected between the first group G1 and the second group G2, and the second switch SW2 is connected between the second group G2 and the third group G3. When the first switch SW1 is turned on, the second group G2 is bypassed. When the second switch SW2 is turned on, the third group G3 is bypassed.

For example, when the input voltage reaches the voltage for turning on the first group G1 while the first switch SW1 is on, the first group G1 emits light. When the input voltage reaches a voltage capable of turning on the first group G1 and the second group G2 while the second switch SW2 is turned on, the first switch SW1 is turned off and the first group G1 is turned off. And the second group G2 emits light. Subsequently, when the input voltage reaches a voltage capable of turning on the first group G1, the second group G2, and the third group G3, the second switch SW2 is turned off and the first group G1 is turned off. , The second group G2 and the third group G3 emit light. Thereafter, when the input voltage falls, the group turned on in the reverse order as described above is decreased, and the operation may be repeated according to the cycle of the input voltage.

The electric element 370 includes a capacitor connected in parallel to the last two LEDs 341 of the third group G3. When current flows in the third group G3, the capacitor is charged by the voltage drop of the last two LEDs 341 of the third group G3. The electric element 370 is electrically connected to the switch control circuit 350. The voltage charged in the electric element 370 is provided to the switch control circuit 350 as an operating power source. For example, the MOSFET or the OP-AMP of the switch control circuit 350 is operated.

In the above-described light emitting operation, the switch control circuit 350 outputs signals sg1 and sg2 for driving the first switch SW1 and the second switch SW2, and receives operating power from the electric element 370. .

On the other hand, the electric element 370 may also supply an operating voltage to elements other than the switch control circuit 350. For example, operating power required for the operation of the first switch SW1 and the second switch SW2 or the microprocessor 360 for controlling the power may be provided from the electric element 370.

Hereinafter, various embodiments of the present disclosure will be described.

(1) The light emitting circuit, characterized in that the electric element comprises a capacitor (capacitor) electrically connected in parallel to the at least one PN junction light emitting element.

(2) The at least one PEN junction light emitting device includes a PEN junction light emitting device positioned last with respect to the high potential terminal of the light emitting group.

(3) The light emitting circuit includes a plurality of light emitting groups connected in series, and the electric element is provided in at least one light emitting group of the plurality of light emitting groups.

(4) a circuit element supplied with an operating power source from an electric element, the light emitting circuit comprising a switch for turning on and off the PJ junction light emitting element.

(5) The light emitting circuit includes a switch for turning on and off the PJ junction light emitting element, wherein the circuit element supplied with the operating power from the electric element comprises a switch control circuit for controlling the switch.

(6) a circuit element supplied with an operating power source from an electric element, the microprocessor for controlling the control of the power source or the light emission.

(7) The light emitting circuit includes a plurality of light emitting groups connected in series, and the at least one PN-junction light emitting device includes the last PN-junction light emitting device of the last light emitting group among the plurality of light emitting groups on the basis of the high potential terminal, Light emitting circuit comprising a capacitor connected in parallel with the at least one PN-junction light emitting device.

(8) The circuit element is connected between a plurality of light emitting groups, and in the on state, the number of light emitting groups whose turn-on voltage is lower than the input voltage based on the high potential is emitted and the remaining light emitting groups are bypassed. At least one switch; A switch control circuit for controlling the switch; And a microprocessor for controlling power supply or light emission of the plurality of light emitting groups; Light emitting circuit comprising at least one of.

(9) A light emitting circuit comprising: a rectifying element for rectifying AC power and supplying a pulse power to a plurality of light emitting groups as an AC direct-driven light emitting circuit.

The light emitting circuit according to the present disclosure is very effective for the AC direct drive light emitting device, but is not limited thereto. For example, when using a plurality of devices such as resistors to secure the operating power of the circuit device in the SMPS method or the DC drive method, the electric device according to the present disclosure may be applied to replace the same.

According to one light emitting circuit according to the present disclosure, the power loss of the light emitting circuit is greatly reduced and the efficiency is improved.

In addition, according to another light emitting circuit according to the present disclosure, the number of elements used in the light emitting circuit is reduced.

In addition, according to another light emitting circuit according to the present disclosure, the heat generation of the light emitting circuit is reduced.

100: light emitting circuit 110: power
120: rectifier circuit 141: LED
170: electric element 350: switch control circuit

Claims (10)

A plurality of light emitting groups connected in series, including a light emitting group having a plurality of PI-connected light emitting elements connected in series;
Circuit elements related to control of power supplied to the plurality of light emitting groups or control of light emission of the plurality of light emitting groups; And
An electrical element provided in the light emitting group having a plurality of series-connected PNJ light emitting devices, the electrical device being electrically connected to at least one PNJ light emitting device among the plurality of PNJ light emitting devices, And an electric element for forming an operating power supply by supplying voltage to the circuit element. The method according to claim 1,
The electric device comprises a capacitor (capacitor) electrically connected in parallel to the at least one PN-junction light emitting device. The method according to claim 1,
And at least one PN-junction light emitting device comprises a PN-junction light emitting device positioned last with respect to the high potential end of the light emitting group having the plurality of series-connected PNJ light emitting devices. delete The method according to claim 1,
And a circuit device supplied with operating power from an electric device, the at least one switch for turning on and off a plurality of light emitting groups. The method according to claim 1,
The light emitting circuit may include at least one switch for turning on and off a plurality of light emitting groups.
The circuit device receiving the operating power from the electrical device comprises a switch control circuit for controlling at least one switch. The method according to claim 1,
The circuit device receiving the operating power from the electrical device is a light emitting circuit comprising a; microprocessor for controlling the control or light emission of the power supply. The method according to claim 2,
And at least one PN-junction light emitting device comprises a PN-junction light emitting device positioned last with respect to the high potential end of the light emitting group having the plurality of series-connected PNJ light emitting devices. The method according to claim 8,
Circuit elements
At least one switch connected between the plurality of light emitting groups, the at least one light emitting group having a turn-on voltage lower than an input voltage based on the high potential in the on state, and bypassing the remaining light emitting groups;
A switch control circuit for controlling at least one switch; And
A microprocessor for controlling power supply or controlling light emission of a plurality of light emitting groups; Light emitting circuit comprising at least one of. The method of claim 9,
The light emitting circuit is an AC direct-driven light emitting circuit, comprising: a rectifier for rectifying AC power to supply pulse power to a plurality of light emitting groups.

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