KR20180054113A - Led lighting apparatus - Google Patents

Abstract

The present invention discloses a light emitting diode lighting device. The light emitting diode lighting device provides a bypass path to a plurality of light emitting diode groups, thereby improving total harmonic distortion (THD) by increasing a step in which a driving current amount is changed and a change step of a light emitting amount. Also, the light emitting diode lighting device improves a flicker by improving a deviation of a light amount by uniformly dispersing a light emitting time for each light emitting diode group. The light emitting diode lighting device comprises: a first light emitting diode group; a bypass path; a second light emitting diode group; and a driver.

Description

LED LIGHTING APPARATUS

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode lighting apparatus, and more particularly, to a light emitting diode lighting apparatus improved in light emitting state of light emitting diode groups.

An illumination device is being developed to utilize a light source having a high luminous efficiency with a small amount of energy for energy saving. A representative light source used in the lighting apparatus may be a light emitting diode (LED).

Light emitting diodes have the advantage of being differentiated from other light sources in various factors such as energy consumption, lifetime and light quality. The light emitting diode has characteristics driven by a current. Therefore, an illumination device using a light emitting diode as a light source has a problem that a lot of additional circuits for current driving are required.

In order to solve the above problems, the lighting device has been developed to provide an AC power source to the light emitting diodes in an AC direct type. The lighting apparatus is configured to convert the alternating current power into a rectified voltage and to cause the light emitting diode to emit light by current driving using a rectified voltage. The lighting device uses a rectified voltage without using an inductor and a capacitor, and thus has a good power factor. The rectified voltage means a voltage in which an AC voltage is full-wave rectified by full-wave rectification of a rectifier.

The AC direct lighting device improves the total harmonic distortion (hereinafter referred to as "THD"), reduces the light deviation when the light emitting state changes, reduces the heat by dispersing the driving current by the LED group, Flicker needs to be improved to improve.

An object of the present invention is to improve the THD by increasing the channel in which the amount of driving current is changed, thereby alleviating the change in the driving current.

Another object of the present invention is to improve the flicker by uniformly dispersing the total light emission time for each light emitting diode group, to reduce the heat generation according to the current dispersion, to improve the light efficiency according to the light emission dispersion, and to improve the life of the light emitting diode group.

According to an aspect of the present invention, there is provided a light emitting diode lighting apparatus comprising: a first light emitting diode group emitting light when a voltage of a first level or higher is applied across both ends; A bypass circuit for maintaining a normally turned-on state by a rectified voltage and selectively providing a bypass path of a driving current in parallel to the first light emitting diode group; Wherein the light emitting diode emits light when a voltage of a second level or higher than the first level is applied between both ends of the first light emitting diode group and the bypass circuit, 2 light emitting diode group; And a driver for providing a current path to each of the first and second light emitting diode groups corresponding to light emission and for regulating the driving current in the current path, The first and second light emitting diode groups emit light corresponding to the rectified voltage of three or more levels and the bypass circuit emits light corresponding to the light emission of the second light emitting diode group corresponding to the rectified voltage of the second level or higher, And the flow of the driving current through the bypass path is blocked by sensing the driving current corresponding to the rectified voltage to which the voltage of the first level or higher is applied across both ends of the bypass circuit. .

In addition, the light emitting diode lighting device of the present invention comprises: a first light emitting diode group which emits light when a voltage of a first level or higher is applied across both ends; A first bypass circuit for selectively providing a first bypass path of a driving current in parallel to the first light emitting diode group; A second light emitting diode group that emits light when a voltage of a second level or higher than the first level is applied between both ends thereof and receives the driving current through either the first light emitting diode group or the bypass circuit during light emission; A second bypass circuit for selectively providing a second bypass path of the driving current to the second light emitting diode group in parallel; Wherein the first light emitting diode group and the second light emitting diode group emit light when a voltage of a fourth level or higher that is higher than a third level that is the sum of the first level and the second level is applied between both ends, A third light emitting diode group that receives the driving current through the first light emitting diode group; And a driver for providing a current path to each of the first to third light emitting diode groups corresponding to the light emission and for regulating the drive current in the current path, And the second light emitting diode group is supplied with the driving current through the first bypass path corresponding to the rectified voltage of the second level and the third level, And the third light emitting diode group receives the drive current through the second bypass path corresponding to a part of the rectified voltage of the fourth level or higher.

Further, the light emitting diode lighting device of the present invention comprises: a first light emitting diode group emitting light when a voltage of a first level or higher is applied across both ends; A bypass circuit for maintaining a normal turn-on state and selectively providing a bypass path of a driving current in parallel to the first light emitting diode group; And a light emitting unit that emits light when a voltage equal to or higher than a second level higher than the first level is applied between the both ends and receives the driving current through the first light emitting diode group and the bypass circuit corresponding to the level of the rectified voltage Wherein the first and second light emitting diode groups emit light corresponding to the rectified voltage of a third level or higher that is the sum of the first level and the second level, Wherein the bypass circuit provides the bypass path corresponding to the light emission of the second light emitting diode group corresponding to the rectified voltage of the second level or higher, and the flow of the driving current through the bypass path is provided between the both ends of the bypass circuit And is cut off by sensing the driving current corresponding to the rectified voltage to which a voltage of two or more levels is applied.

Therefore, according to the present invention, the channel in which the amount of driving current is changed can be increased, and the amount of change in the increased current per channel can be reduced, so that the change in driving current can be mitigated, thereby improving the THD.

Further, the present invention can improve the flicker by evenly dispersing the total light emission time for each light emitting diode group.

The dispersion of the current can reduce the heat generation by each light emitting diode group, and the light efficiency can be improved as the light emission is dispersed.

As described above, the lifetime of the light emitting diode groups can be improved as the light emitting time of each light emitting diode group is dispersed.

1 is a circuit diagram showing a preferred embodiment of a light-emitting diode lighting device of the present invention.
FIG. 2 is a detailed circuit diagram of the bypass circuits, the illumination unit, and the driver of FIG. 1;
3 is a detailed circuit diagram of the driver of Fig.
Figure 4 is a waveform diagram according to the operation of the embodiment of Figure 1;
5 is a table for explaining light emission state change of the embodiment;
6 is a circuit diagram showing another embodiment of the light emitting diode illumination device of the present invention.
FIG. 7 is a detailed circuit diagram of the bypass circuits, the illumination unit, and the driver of FIG. 6;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood that the terminology used herein is for the purpose of description and should not be interpreted as limiting the scope of the present invention.

The embodiments described in the present specification and the configurations shown in the drawings are preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention and thus various equivalents and modifications Can be.

The illumination device of the present invention may use a light source having semiconductor light emission characteristics for converting electrical energy into light energy, and the light source having semiconductor light emission characteristics may include a light emitting diode.

The illumination device of the present invention is disclosed as being driven in an AC direct manner. The AC direct method means that the light emitting diode emits light using the rectified voltage Vrec obtained by converting the AC power.

Here, the rectified voltage Vrec has a waveform of full-wave rectification of an AC voltage having a sinusoidal waveform. That is, the rectified voltage Vrec has a ripple component whose level rises and falls by a half cycle of the commercial AC voltage. The current flowing in the lighting device corresponding to the rectified voltage Vrec is referred to as a driving current Irec.

1, an embodiment of the lighting apparatus of the present invention may include a power supply unit 100, an illumination unit 200, a driver 300, and bypass circuits 400 and 410.

The power supply unit 100 has a configuration for full-wave rectification of the AC voltage of the AC power supply and outputting it with the rectified voltage Vrec. The power supply unit 100 may include an AC power supply VAC for providing an AC voltage and a rectifier circuit 120 for full-wave rectifying the AC voltage to output a rectified voltage Vrec.

Here, the AC power supply (VAC) may be a commercial power supply. In the embodiment of the present invention, the rise or fall of the rectified voltage Vrec can be understood to mean a rise or a fall of the ripple component.

The illumination unit 200 includes light emitting diodes, and the light emitting diodes are divided into one or more light emitting diode groups. The light emitting diode groups are emitted and extinguished by increasing or decreasing the rectified voltage Vrec provided by the power supply unit 100.

In FIG. 1, the illumination unit 200 is illustrated as including three light-emitting diode groups (LED1 to LED3) connected in series. Each of the light emitting diode groups (LED1 to LED3) may include one or more light emitting diodes.

The light emitting diode group LED1 can emit light when a voltage of the first level V1 or higher is applied across both ends and the light emitting diode group LED2 emits light when a voltage of the second level V2 or higher is applied across the both ends. Wherein the second level V2 is higher than the first level V1. The light emitting diode group LED3 emits light when a voltage higher than a fourth level V4 higher than a third level V3, which is a sum of the first level V1 and the second level V2, is applied across the two ends. For example, the ratio of the first level (V1): the second level (V2): the fourth level (V4) may be set to 1: 2: 4.

The driver 300 provides a current path to one of the light emitting diode groups LED1 to LED3 corresponding to the light emission of the light emitting diode groups LED1 to LED3 according to the change of the rectified voltage Vrec, As shown in FIG.

The driver 300 has channel terminals CH1 to CH3, a ground terminal GND for connection to the ground, and a sensing terminal Riset to which a sensing resistor Rs is connected. The driver 300 controls the change of the current path between the channel terminals CH1 to CH3 and the sensing terminal Riset.

The driver 300 is configured to provide a current path to the light emitting diode groups LED1 to LED3 by comparing the sensing voltage of the sensing resistor Rs with the reference voltages corresponding to the light emitting diode groups LED1 to LED3 .

The embodiment of the present invention is implemented by including three light emitting diode groups LED1 to LED3 and the output terminal of the light emitting diode group LED1 is connected to the light emitting diode group LED2 And an output terminal of the light emitting diode group LED2 is connected to an input terminal of the light emitting diode group LED3 through a diode Db and a resistor Rb connected in series. The diodes Da and Db prevent the current from flowing in the reverse direction and the resistors Ra and Rb can be used for sensing the driving current Irec.

Of the channel terminals CH1 to CH3 of the driver 300, the channel terminal CH1 is connected to a node between the output terminal of the light emitting diode group LED1 and the diode Da, Is connected between the output terminal of the diode group LED2 and the diode Db and the channel terminal CH3 is connected to the output terminal of the light emitting diode group LED3.

The resistor Ra is configured between the diode Da and the input terminal of the light emitting diode group LED2 and the resistor Rb is configured between the diode Db and the input terminal of the light emitting diode group LED3. The resistors Ra and Rb may be composed of a wiring or other element having a resistance component capable of equivalently sensing a current. The resistance Ra may be configured to have a resistance value larger than the resistance Rb.

The sensing resistor Rs connected to the sensing resistor Riset of the driver 300 is connected to the current path inside the driver 300. [ The sensing resistance Rs senses the driving current Irec output from the driver 300 and provides a sensing voltage corresponding to the level of the driving current Irec.

The driving current Irec flowing through the sensing resistor Rs may be changed according to the level of the rectified voltage Vrec which changes the light emission state of the light emitting diode groups LED1 to LED3 of the illumination unit 200. [

In the embodiment of the present invention, while the rectified voltage Vrec rises within one period, the light emitting state of the illumination unit 200 is switched between the light emission of the light emitting diode group LED1, the light emission of the light emitting diode group LED2, The light emission of the light emitting diode group (LED3), the light emission of the light emitting diode groups (LED2, LED3), and the light emission of the light emitting diode groups (LED1 to LED3). Then, while the rectified voltage Vrec falls at the peak level MAX within one period, the light emitting state of the illumination unit 200 changes in the reverse order of the rise of the rectified voltage Vrec.

The rectified voltage Vrec for causing the light emitting diode group LED1 to emit light can be defined as the first level V1 and the rectified voltage Vrec for emitting the light emitting diode group LED2 can be defined as the second level The rectification voltage Vrec for emitting all the light emitting diode groups LED1 and LED2 can be defined as the third level V3 and the rectified voltage Vrec for emitting the light emitting diode group LED3 Can be defined as a fourth level (V4). The rectified voltage Vrec for causing the light emitting diode groups LED2 and LED3 to emit light can be defined as a fifth level V5 and the sum of the second level V2 and the fourth level V4 . The rectified voltage Vrec for causing the light emitting diode groups LED1 to LED3 to emit light is defined as the sixth level V6 and the first level V1, the second level V2, and the fourth level V4, And is formed to be equal to or less than the peak level MAX.

The rectified voltage Vrec of one period rises to the peak level MAX sequentially from the first level V1 to the sixth level V6 at the lowest level (0 V), and thereafter increases from the peak level MAX to the sixth level (V6) to the first level (V1) sequentially to the lowest level (0V).

Meanwhile, the bypass circuit 400 is configured in parallel with the light emitting diode group LED1 with respect to the rectified voltage Vrec, and selectively provides the first bypass path. The bypass circuit 410 is configured in parallel with the light emitting diode group LED2 with respect to the rectified voltage Vrec, and selectively provides the second bypass path. More specifically, the bypass circuit 400 selectively provides a first bypass path in parallel with the diode Da to the light emitting diode group LED2, and the bypass circuit 410 is connected to the light emitting diode group LED3 And selectively provides a second bypass path in parallel with the diode Db.

The bypass circuits 400 and 410 maintain the normally turn-on state corresponding to the rectified voltage Vrec.

The light emitting diode group LED2 is turned on in response to the rectified voltage Vrec of less than the second level V2 and the third level V3 by the first bypass formed in the bypass circuit 400 which is normally turned on, And the drive current Irec is supplied through the path.

The light emitting diode group LED3 is supplied with the driving current Irec through the second bypass path formed in the bypass circuit 410 which is normally turned on corresponding to a part of the rectified voltage Vrec of the fourth level V4 or more .

More specifically, the bypass circuit 410 provides all or part of the driving current Irec by the rectified voltage Vrec higher than the fourth level V4 and lower than the sixth level V6 to the light emitting diode group LED3. Alternatively, the bypass circuit 410 provides the driving current Irec by the rectified voltage Vrec at the fourth level (V4 level) or more and the fifth level (V5 level) to the light emitting diode group LED3. The above case can be changed by adjusting the resistance value of the resistors Ra and Rb or by serial or parallel configuration of the bypass circuits 400 and 410, and a detailed description thereof will be described later.

As a result, the bypass circuit 400 provides a first bypass path to the input terminal of the light emitting diode group LED2 corresponding to the light emission of the light emitting diode group LED2 and the light emission of the light emitting diode groups LED2 and LED3 . The bypass circuit 410 provides the second bypass path to the input terminal of the third light emitting diode group LED3 corresponding to the light emission of the light emitting diode group LED3. In addition, the bypass circuit 410 is provided between the bypass circuit 400 and the input terminal of the light emitting diode group (LED3) in order to distribute the driving current Irec corresponding to the light emission of the light emitting diode groups (LED2, LED3) 2 bypass path.

The bypass circuit 400 can regulate the driving current Irec in response to the light emission of the light emitting diode group LED2 and the bypass circuit 410 regulates the driving current Irec in response to the light emission of the light emitting diode group LED3, can do.

At this time, the constant current level regulated by the bypass circuit 400 is preferably set lower than the constant current level regulated by the bypass circuit 410.

The constant current level regulated by the bypass circuit 400 is lower than the constant current level due to the regulation of the driver 300 that provides the current path to the output terminal of the light emitting diode group LED2 or the output terminal of the light emitting diode group LED3 Preferably set. The constant current level regulated by the bypass circuit 410 is preferably set lower than the constant current level due to the regulation of the driver 300 that provides the current path to the output terminal of the light emitting diode group LED3.

The bypass circuits 400 and 410 may be configured in series or in parallel with respect to the rectified voltage Vrec. The configuration of the bypass circuits 400 and 410 in series with respect to the rectified voltage Vrec is exemplified by the embodiment of FIGS. 1 and 2. The configuration of the bypass circuits 400 and 410 in parallel with the rectified voltage Vrec 6 and 7.

The configuration of the embodiment of FIG. 1 will be described in more detail with reference to FIG.

The light emitting diode groups LED1 to LED3 included in the illumination unit 200 are illustrated to include a different number of light emitting diodes. More specifically, the light emitting diode group LED1 includes five light emitting diodes, the light emitting diode group LED2 includes ten light emitting diodes, and the light emitting diode group LED3 includes twenty light emitting diodes. do. Each of the light emitting diodes is preferably configured so that the voltage between both ends required for light emission is the same. According to the above configuration, the voltage between both ends of the light-emitting diode groups LED1 to LED3 required for light emission is different between the first level V1, the second level V2 and the fourth level V4.

The bypass circuit 400 includes an NMOS transistor Q2 connected in parallel to the light emitting diode group LED1 and an NPN bipolar transistor Q1 controlling the operation of the NMOS transistor Q2.

The NMOS transistor Q2 supplies the drive current Irec to the input terminal of the light emitting diode group LED2 through the source and the resistor Ra in a state in which the rectified voltage Vrec is applied to the drain and turned on. A rectified voltage Vrec is applied to the gate of the NMOS transistor Q2 through the resistor R1. Therefore, when the gate voltage is not influenced by the NPN bipolar transistor Q1, which will be described later, the NMOS transistor Q2 maintains the normal turn-on state with respect to the rectified voltage equal to or higher than the threshold voltage and forms the first bypass path. The flow of the driving current Irec through the NMOS transistor Q2 can be controlled by the operation of the NPN bipolar transistor Q1.

The NPN bipolar transistor Q1 senses the amount of the driving current Irec flowing through the resistor Ra through the resistor R2. The NPN bipolar transistor Q1 controls the driving current Irec flowing through the NMOS transistor Q2 to flow below a predetermined constant current level by the sensing of the driving current. More specifically, the NPN bipolar transistor Q1 senses the amount of the driving current Irec flowing through the resistor Ra through the resistor R2 and controls the gate of the NMOS transistor Q2 according to the voltage level applied to the resistor R2. Adjust the voltage. That is, the NPN bipolar transistor Q1 regulates the drive current Irec of the first bypass path by the NMOS transistor Q2.

The bypass circuit 410 also includes an NMOS transistor Q4 connected in parallel to the light emitting diode group LED2 and an NPN bipolar transistor Q3 controlling the operation of the NMOS transistor Q4.

The NMOS transistor Q4 is turned on when the rectified voltage Vrec is applied to the drain through the NMOS transistor Q2 in the normally turned-on state and the driving current Irec is supplied to the input terminal of the light emitting diode group LED3 through the source and the resistor Rb to provide. A rectified voltage Vrec is applied to the gate of the NMOS transistor Q4 through the resistor R3. Therefore, when the gate voltage is not influenced by the NPN bipolar transistor Q3 described later, the NMOS transistor Q4 maintains the normal turn-on state with respect to the rectified voltage equal to or higher than the threshold voltage and forms the second bypass path. The flow of the driving current Irec through the NMOS transistor Q4 can be controlled by the operation of the NPN bipolar transistor Q3.

The NPN bipolar transistor Q3 senses the amount of the driving current Irec flowing through the resistor Rb through the resistor R2. The NPN bipolar transistor Q3 controls the driving current Irec flowing through the NMOS transistor Q4 to flow below a predetermined constant current level by the sensing of the driving current.

More specifically, the NPN bipolar transistor Q3 senses the amount of the driving current Irec flowing through the resistor Ra through the resistor R4 and controls the gate of the NMOS transistor Q4 according to the voltage level applied to the resistor R4. Adjust the voltage. That is, the NPN bipolar transistor Q3 regulates the drive current Irec of the first bypass path by the NMOS transistor Q4.

On the other hand, the detailed configuration and the operation of the driver 300 will be described with reference to FIG.

The driver 300 includes switching circuits 31 to 33 and a reference voltage supply 30 for providing reference voltages VREF1 to VREF3.

The output terminal of the light emitting diode group (LED1) is connected to the switching circuit (31) through the channel terminal (CH1) of the driver (300). The output terminal of the light emitting diode group LED2 is connected to the switching circuit 32 through the channel terminal CH2 of the driver 300. The output terminal of the light emitting diode group (LED3) is connected to the switching circuit (33) through the channel terminal (CH3) of the driver (300).

The reference voltage supply unit 30 may be implemented by providing reference voltages VREF1 to VREF3 at various levels according to the manufacturer's intention.

The reference voltage supply unit 30 may include a plurality of series-connected resistors to which the constant voltage VDD is applied, and may be configured to output reference voltages VREF1 to VREF3 of different levels for each node between the resistors.

The reference voltage supplier 30 may be configured to include independent voltage sources that provide reference voltages VREF1 to VREF3 of different levels, respectively.

The reference voltage supply unit 30 shares the ground and is connected to the ground terminal GND for this purpose.

The reference voltages VREF1 to VREF3 at different levels have the lowest voltage level of the reference voltage VREF1, the highest voltage level of the reference voltage VREF3, and the reference voltages VREF1 to VREF3 gradually decrease in the order of the reference voltages VREF1, VREF2, It can be set to have a high level.

Here, the reference voltage VREF1 is lower than the sensing voltage of the sensing resistor Rs at the time when the light emitting diode group LED2 emits light, and has a level for turning off the switching circuit 31. [

The reference voltage VREF2 is lower than the sensing voltage of the sensing resistor Rs at the time when the light emitting diode group LED3 emits light and has a level for turning off the switching circuit 32. [

The reference voltage VREF3 is preferably set to be equal to or higher than the sensing voltage of the corresponding sensing resistor Rs up to the peak level MAX of the rectified voltage Vrec.

Meanwhile, the switching circuits 31 to 33 are commonly connected to the sensing resistor Rs through a sensing terminal Riset for current regulation and current path formation.

The switching circuits 31 to 33 compares the sensing voltage of the sensing resistor Rs with the reference voltages VREF1 to VREF3 of the reference voltage supplier 30 to determine the corresponding voltages of the light emitting diode groups LED1 to LED3 Thereby forming a current path.

The switching circuits 31 to 33 are provided with a higher level reference voltage as they are connected to the light emitting diode group far from the position where the rectified voltage is applied.

Each of the switching circuits 31 to 33 preferably includes a comparator 36 and a switching element, and the switching element is composed of an NMOS transistor 37.

The comparator 36 of each of the switching circuits 31 to 33 receives a reference voltage applied to the positive input terminal (+), a sensing voltage applied to the negative input terminal (-), and a comparison result of the reference voltage and the sensing voltage Output.

The NMOS transistor 37 of each of the switching circuits 31 to 33 performs an operation for controlling the flow of the driving current Irec in accordance with the output of each comparator 36 applied to the gate.

The description of the embodiment of the present invention constructed as shown in Figs. 1 to 3 will be explained with reference to Figs. 4 and 5. Fig.

In Fig. 4, ILED1 is a driving current flowing in the light emitting diode group LED1, ILED2 is a driving current flowing in the light emitting diode group LED2, and ILED3 is a driving current flowing in the light emitting diode group LED3. Vbp1 is a voltage applied to both ends of the bypass circuit 400 and Ibp1 is a driving current flowing through the first bypass path of the bypass circuit 400. [ Vbp2 is a voltage applied to both ends of the bypass circuit 410 and Ibp2 is a driving current flowing through the second bypass circuit of the bypass circuit 410. [

FIG. 4 shows changes in the light emission state of the light emitting diode groups LED1 to LED3 in the process of changing one period of the rectified voltage Vrec, and a hatched portion means that the corresponding light emitting diode group emits light. The light emitting state changes of the light emitting diode groups LED1 to LED3 of FIG. 4 are the same as the ON state of the light emitting diode groups LED1 to LED3 of FIG.

In the embodiment of the present invention, the rectified voltage Vrec of one period rises to the peak level MAX sequentially from the first level (V1) to the sixth level (V6) at the lowest level (0 V) MAX to the lowest level (0V) sequentially through the sixth level (V6) to the first level (V1).

The reference voltage VREF1 to VREF3 applied to the positive input terminal (+) of the comparator 36 is applied to the negative input terminal of the comparator 36. In the case where the rectified voltage Vrec is in the initial state, Is higher than the sensing voltage applied to the negative polarity (-). At this time, the light emitting diode groups (LED1 to LED3) are in an extinction state.

When the rectified voltage Vrec rises in the initial state to reach the first level V1, the light emitting diode group LED1 emits light as the voltage of the first level V1 is applied to both ends thereof. When the light emitting diode group LED1 emits light, the driving current Irec flows through the current path of the light emitting diode group LED1 and the switching circuit 31 of the driver 300. At this time, the current ILED1 flowing through the light emitting diode group LED1 increases to the same level as the driving current Irec as shown in FIG.

When the rectified voltage Vrec increases in a state in which the light emitting diode group LED1 emits light, the switching circuit 31 sets the amount of the driving current Irec based on the reference voltage VREF1 applied to the positive input terminal (+) of the comparator 36 Regulate below the set constant current level.

When the rectified voltage Vrec rises from the first level V1 to reach the second level V2, the light emitting diode group LED2 receives the rectified voltage Vrec through the bypass circuit 400 in the normal turn-on state, And emits light by the applied voltage of the second level (V2). When the light emitting diode group LED2 emits light, the driving current Irec flows to the light emitting diode group LED2 through the first bypass path by the NMOS transistor Q2 of the bypass circuit 400. [ At this time, the switching circuit 32 of the driver 300 provides a current path corresponding to the light emission of the light emitting diode group LED2.

The amount of the driving current Irec due to the light emission of the above-described light emitting diode group LED2 is increased with the rise of the rectified voltage Vrec. The current ILED2 flowing through the light emitting diode group LED2 is increased as shown in Fig. Therefore, the sensing resistor Rs provides an increased level of sensing voltage proportional to the increase in the driving current Irec, and the switching circuit 31 of the driver 300 is applied to the positive input (+) of the comparator 36 The sensing voltage applied to the negative input terminal (-) becomes higher than the reference voltage VREF1 and is therefore turned off, the light emitting diode group LED1 is extinguished, and the current ILED1 flowing through the light emitting diode group LED1 is reduced.

That is, corresponding to the light emission of the light emitting diode group LED2, the drive current Irec is supplied to the first bypass path by the bypass circuit 400, the light emitting diode group LED2 and the switching circuit 32 of the driver 300 Lt; / RTI >

At this time, the voltage Vbp1 and the current Ibp1 of the NMOS transistor Q2 forming the first bypass path of the bypass circuit 400 rise as shown in Fig.

The bypass circuit 400 and the switching circuit 32 of the driver 300 perform regulation based on different constant current levels with respect to the driving current Irec due to the light emission of the light emitting diode group LED2. The embodiment of the present invention sets the constant current level of the bypass circuit 400 to be lower than the constant current level of the switching circuit 32 of the driver 300. [

Therefore, the driving current Irec is regulated by the bypass circuit 400 while the light emitting diode group LED2 emits light, and the bypass circuit 400 is controlled by the voltage sensing the driving current Irec flowing through the resistor Ra Thereby regulating the driving current Irec.

When the rectified voltage Vrec rises above the second level V2 after the light emitting diode group LED2 emits light, the voltage applied between the two ends of the light emitting diode group LED2 is fixed, and the rectified voltage Vrec and the second level V2 ) Is applied between the both ends of the bypass circuit 400, that is, between the drain and the source of the NMOS transistor Q2.

As the rectified voltage Vrec rises, the surplus voltage applied across the both ends of the bypass circuit 400 gradually rises. The light emitting diode group LED1 further emits light when the surplus voltage applied across the both ends of the bypass circuit 400 reaches the first level V1 at which the light emitting diode group LED1 can emit light. At this time, it can be understood that the rectified voltage Vrec reaches the third level (V3) which is the sum of the first level (V1) and the second level (V2).

When the light emitting diode group LED1 further emits light, the bypass circuit 400 connected in parallel acts as a resistor by regulation. Therefore, the driving current Irec flows through the light emitting diode group LED1, which is switched to an electrical conduction state by light emission, and the flow of the driving current Irec through the first bypass path of the bypass circuit 400 is stopped do. At this time, the voltage Vbp1 applied across the NMOS transistor Q2 of the bypass circuit 400 maintains the same level as the voltage applied across the light-emitting diode group LED1 as shown in FIG. 4, The current Ibp1 of the transistor 400 is reduced.

As described above, when the rectified voltage Vrec reaches the third level, the light emitting diode groups LED1 and LED2 emit light and the driving current Irec is applied to the light emitting diode group LED1, the light emitting diode group LED2, And flows through the current path by the switching circuit 32.

The amount of the driving current Irec due to the light emission of the light emitting diode groups LED1 and LED2 increases as the rectified voltage Vrec increases. But. The switching circuit 32 of the driver 300 maintains the turn-on state since the sensing voltage applied to the negative input terminal (-) is lower than the reference voltage VREF2 applied to the positive input terminal (+) of the comparator 36. [

The driving current Irec is regulated by the switching circuit 32 of the driver 300 in a state in which the light emitting diode groups LED1 and LED2 emit light as described above. The constant current level for regulation of the switching circuit 32 of the driver 300 is set higher than the bypass circuit 400. [ Therefore, the amount of the driving current Irec corresponding to the light emission of the light emitting diode groups (LED1, LED2) increases as compared with the light emission of the light emitting diode group (LED2).

When the rectified voltage Vrec increases in a state in which the light emitting diode groups LED1 and LED2 emit light, the switching circuit 32 switches the reference voltage VREF2 applied to the positive input terminal (+) of the comparator 36, And the amount is regulated below a predetermined constant current level.

When the rectified voltage Vrec rises from the third level V3 to reach the fourth level V4, the light emitting diode group LED3 is turned on through the bypass circuit 400 and the bypass circuit 410 in the normal turn- And the rectified voltage Vrec of the fourth level (V4) to be applied to the pixel electrode. When the light emitting diode group LED3 emits light, the driving current Irec is provided to the light emitting diode group LED3 through the first bypass path of the bypass circuit 400 and the second bypass path of the bypass circuit 410 , The turned-on switching circuit 33 of the driver 300 connected to the light emitting diode group LED3 provides a current path corresponding to the light emission of the light emitting diode group LED3.

The amount of the driving current Irec due to the light emission of the light emitting diode group LED3 is increased with the increase of the rectified voltage Vrec and the current ILED3 flowing through the light emitting diode group LED3 is increased as shown in FIG. Therefore, the sensing resistor Rs provides a sensing voltage of a level proportional to the increased amount of the driving current Irec and the switching circuit 32 of the driver 300 is applied to the positive input (+) of the comparator 36 The sensing voltage applied to the negative input terminal (-) becomes higher than the reference voltage VREF2, so that the light emitting diode groups LED1 and LED2 are turned off.

That is, corresponding to the light emission of the light emitting diode group (LED3), the drive current Irec is supplied to the first bypass path by the bypass circuit 400, the second bypass path by the bypass circuit 410, LED3) and the current path by the switching circuit 33 of the driver 300.

At this time, the drain-source voltage Vbp2 and the current Ibp2 of the NMOS transistor Q4 of the bypass circuit 410 rise as shown in Fig. The voltage Vbp1 is not formed between both ends of the NMOS transistor Q2 of the bypass circuit 400 and only the current Ibp1 flows.

The current flowing from the bypass circuit 400 to the light emitting diode group LED2 corresponding to the light emission of the light emitting diode group LED3 is not sensed. Therefore, bypass circuit 400 provides a first bypass path for current flow without performing regulation. The bypass circuit 410 and the switching circuit 33 of the driver 300 perform regulation based on different constant current levels with respect to the driving current Irec due to the light emission of the light emitting diode group LED3. The embodiment of the present invention sets the constant current level of the bypass circuit 410 to be lower than the constant current level of the switching circuit 33 of the driver 300. [

Therefore, the driving current Irec is regulated by the bypass circuit 410 while the light emitting diode group LED3 emits light, and the bypass circuit 410 controls the driving current Irec flowing through the resistor Rb Thereby regulating the driving current Irec.

When the rectified voltage Vrec rises above the fourth level V4 after the light emitting diode group LED3 emits light, the voltage applied across the light emitting diode group LED3 is fixed, and the rectified voltage Vrec and the fourth level V4 ) Is applied between the both ends of the bypass circuit 410, that is, across the both ends of the NMOS transistor Q4.

The surplus voltage applied to both ends of the bypass circuit 410 gradually increases due to the rise of the rectified voltage Vrec. When the surplus voltage applied to both ends of the bypass circuit 410 reaches the second level V2 at which the light emitting diode group LED2 can emit light, the light emitting diode group LED2 further emits light. At this time, it can be understood that the rectified voltage Vrec reaches the fifth level (V5), which is the sum of the second level (V2) and the fourth level (V4).

When the light emitting diode group LED2 further emits light, the bypass circuit 410 connected in parallel acts as a resistor by regulation. Therefore, the driving current Irec flows through the light emitting diode group LED2, which is switched to an electrical conduction state by light emission, and the flow of the driving current Irec through the second bypass path of the bypass circuit 410 is stopped do. At this time, the voltage Vbp2 applied between the both ends of the NMOS transistor Q4 of the bypass circuit 410 maintains the same level as the voltage applied to both ends of the LED group LED2 as shown in Fig. 4, The current Ibp2 of the transistor 410 is reduced.

As described above, when the rectified voltage Vrec reaches the fifth level V5, the light emitting diode groups LED2 and LED3 emit light, and the driving current Irec flows through the first bypass path of the bypass circuit 400, (LED2), the light emitting diode group (LED2), and the switching circuit 33 of the driver 300.

The amount of the driving current Irec due to the light emission of the light emitting diode groups LED2 and LED3 is increased as the rectified voltage Vrec rises. The switching circuit 33 of the driver 300 maintains the turn-on state since the sensing voltage applied to the negative input terminal (-) of the comparator 36 is lower than the reference voltage VREF2 applied to the positive input terminal (+) of the comparator 36 do.

The bypass circuit 400 and the switching circuit 33 of the driver 300 perform regulation based on different constant current levels with respect to the driving current Irec due to the light emission of the light emitting diode groups LED2 and LED3. The embodiment of the present invention is set such that the constant current level of the bypass circuit 400 is lower than the constant current level of the switching circuit 33 of the driver 300. [

Therefore, the drive current Irec is regulated by the bypass circuit 400, and the bypass circuit 400 regulates the drive current Irec by the voltage sensing the drive current Irec flowing through the resistor Ra.

The bypass circuit 410 regulates by the bypass circuit 400 and provides a second bypass path for the remaining driving current Irec. In other words, the driving current Irec can be distributed to the bypass circuit 400 and the bypass circuit 410 to flow. In this case, the current by the bypass circuit 410 is regulated by the bypass circuit 410.

Thereafter, when the rectified voltage Vrec rises above the fifth level (V5), the voltage applied across the light-emitting diode group LED2 and the light-emitting diode group LED3 is fixed. Almost all the surplus voltage corresponding to the difference between the rectified voltage Vrec and the fifth level V5 becomes a bias voltage at the drain terminal of the NMOS transistor Q2 through the resistor R1 as shown in Fig. And is therefore not applied to the bypass circuit 400, that is, between the drain and the source of the NMOS transistor Q2.

When the surplus voltage applied to both ends of the bypass circuit 400 reaches the first level V1 at which the light emitting diode group LED1 can emit light due to the rise of the rectified voltage Vrec, . At this time, it can be understood that the rectified voltage Vrec has reached the sixth level V6 which is the sum of the first level (V1), the second level (V2) and the fourth level (V4).

When the light emitting diode group LED1 further emits light, the bypass circuit 400 connected in parallel is current limited by regulation. Therefore, the driving current Irec flows through the light emitting diode group LED1, which is switched to an electrical conduction state by light emission, and the flow of the driving current Irec through the first bypass path of the bypass circuit 400 is stopped do.

As described above, when the rectified voltage Vrec reaches the sixth level V6, the light emitting diode groups LED1, LED2, and LED3 emit light, and the driving current Irec is applied to the light emitting diode group LED1, the light emitting diode group LED2, Through the current path by the light emitting diode group (LED3) and the switching circuit 33 of the driver 300.

The switching circuit 33 of the driving current driver 300 of the light emitting diode groups LED1, LED2 and LED3 is turned on and off by the comparator 36 under the reference voltage VREF3 applied to the positive input terminal (+ Since the sensing voltage applied to the negative input terminal (-) is formed, the turn-on is maintained.

The driving current Irec is regulated by the switching circuit 33 of the driver 300 in a state in which the light emitting diode groups LED1, LED2, and LED3 emit light as described above. Therefore, the amount of the driving current Irec corresponding to the light emission of the light emitting diode groups (LED1, LED2, LED3) increases with the rise of the rectified voltage Vrec.

The rectified voltage Vrec rises above the sixth level to reach the peak level MAX, and then falls from the peak level MAX to the sixth level V6. The light emission of the light emitting diode groups LED1, LED2 and LED3 is maintained during the change of the rectified voltage Vrec and the driving current Irec is applied to the light emitting diode group LED1, the light emitting diode group LED2, the light emitting diode group LED3, And flows through the current path by the switching circuit 33 of the driver 300.

Thereafter, the rectified voltage Vrec falls sequentially from the sixth level (V6) to the lowest level (0V).

As the level of the rectified voltage Vrec is lowered, the light emitting state of the illumination unit 200 according to the embodiment of the present invention is changed from the light emission of the light emitting diode groups LED1 to LED3, the light emission of the light emitting diode groups LED2 and LED3, The light emission of the diode group LED3, the light emission of the light emitting diode groups LED1 and LED2, the light emission of the light emitting diode group LED2, and the light emission of the light emitting diode group LED1.

That is, corresponding to the rising and falling of the rectified voltage Vrec of one period, the light emitting state of the illumination unit 200 can be changed as shown in Fig.

The embodiment of the present invention described with reference to Figs. 1 to 5 exemplifies that the bypass circuits 400 and 410 are configured in series with respect to the rectified voltage Vrec.

Alternatively, the embodiments of the present invention can configure the bypass circuits 400 and 410 in parallel with respect to the rectified voltage Vrec. An embodiment of this can be configured as shown in Figs. 6 and 7. Fig.

6 and 7, the bypass circuits 400 and 410 have different configurations, and the remaining configurations are the same and operate in the same concept, so duplicate descriptions thereof will be omitted.

6 and 7, the first bypass path by the bypass circuit 400 and the second bypass path by the bypass circuit 410 are configured in parallel.

Therefore, the bypass circuit 400 provides a bypass path for the light emission of the light emitting diode group LED2 and the light emission of the light emitting diode groups LED2 and LED3, and performs regulation on the driving current Irec.

The bypass circuit 410 provides a bypass path for light emission of the light emitting diode group LED3 and performs regulation on the driving current Irec.

1 and 2, the bypass circuit 410 has a driving current Irec exceeding the constant current level due to the regulation of the bypass circuit 400 when the light emitting diode groups LED2 and LED3 emit light, Lt; RTI ID = 0.0 > a < / RTI >

As described above, in the present invention, the channel in which the amount of driving current is changed is divided into twelve steps with respect to one period of rectified voltage. Therefore, the amount of driving current can be changed in a larger number of steps than in the case of sequentially emitting three light-emitting diode groups, and as a result, the change in the total driving current can be alleviated.

In addition, since the driving current for each light emitting diode group is more uniformly allocated to the rectified voltage of one cycle, the light amount deviation of each light emitting diode can be reduced.

Therefore, the lighting device of the present invention can improve THD and flicker.

In addition, the lighting apparatus of the present invention can disperse light-emitting time for each light-emitting diode group similarly by dispersing light-emitting diode groups that emit light by each light-emitting state. Therefore, the heat generation can be reduced for each light emitting diode group by the dispersion of the current, and the light efficiency can be improved as the light emission is dispersed.

In addition, the lifetime of the light emitting diode groups can be improved as the light emitting time of each light emitting diode group is dispersed.

Claims (15)

A first light emitting diode group emitting light when a voltage of a first level or higher is applied across both ends;
A bypass circuit for maintaining a normally turned-on state by a rectified voltage and selectively providing a bypass path of a driving current in parallel to the first light emitting diode group;
Wherein the light emitting diode emits light when a voltage of a second level or higher than the first level is applied between both ends of the first light emitting diode group and the bypass circuit, 2 light emitting diode group; And
And a driver for providing a current path to each of the first and second light emitting diode groups corresponding to the light emission and regulating the drive current in the current path,
The first and second light emitting diode groups emit light corresponding to the rectified voltage of the third level or higher, which is the sum of the first level and the second level,
Wherein the bypass circuit provides the bypass path corresponding to the light emission of the second light emitting diode group corresponding to the rectified voltage of the second level or higher,
Wherein the flow of the driving current through the bypass path is blocked by sensing the driving current corresponding to the rectified voltage to which the voltage of the first level or higher is applied across the bypass circuit. The method according to claim 1,
Further comprising a diode between an output terminal of the first light emitting diode group and an input terminal of the second light emitting diode group,
Wherein the bypass circuit selectively provides the bypass path to the second light emitting diode group in parallel with the diode. The method according to claim 1,
Wherein the bypass circuit senses the driving current inputted to the second light emitting diode group and cuts off the bypass path corresponding to the driving current based on the rectified voltage of the third level or higher. Device. The method of claim 3,
And a resistor for sensing the driving current between the output terminal of the first light emitting diode group and the input terminal of the second light emitting diode group. The power supply circuit according to claim 3,
A first element connected in parallel to the first light emitting diode group and used for forming the bypass path by maintaining a normally turn-on state corresponding to the rectified voltage; And
And a second element for blocking the bypass path by the first element when the amount of the driving current inputted to the second light emitting diode group corresponds to the rectified voltage of the third level or higher, . 6. The method of claim 5,
Wherein the second element controls the amount of the driving current flowing through the bypass path by the first element to be regulated. The method according to claim 1,
Wherein the bypass circuit regulates the flow of the driving current to a level of a second constant current lower than a first constant current level regulated by the driver. The light emitting diode according to claim 1, wherein the first light emitting diode group
Light emission of the first light emitting diode group corresponding to the rectified voltage of the first level or higher and lower than the second level;
Light emission of the second light emitting diode group corresponding to the rectified voltage above the second level and below the third level; And
And light emission of the first and second light emitting diode groups corresponding to the rectified voltage of the third level or higher. A first light emitting diode group emitting light when a voltage of a first level or higher is applied across both ends;
A first bypass circuit for selectively providing a first bypass path of a driving current in parallel to the first light emitting diode group;
A second light emitting diode group that emits light when a voltage of a second level or higher than the first level is applied between both ends thereof and receives the driving current through either the first light emitting diode group or the bypass circuit during light emission;
A second bypass circuit for selectively providing a second bypass path of the driving current to the second light emitting diode group in parallel;
Wherein the first light emitting diode group and the second light emitting diode group emit light when a voltage of a fourth level or higher that is higher than a third level that is the sum of the first level and the second level is applied between both ends, A third light emitting diode group that receives the driving current through the first light emitting diode group; And
And a driver for providing a current path to each of the first to third light emitting diode groups corresponding to the light emission, and for regulating the drive current in the current path,
Wherein the first and second bypass circuits maintain a normal turn-on state corresponding to the rectified voltage,
The second light emitting diode group is provided with the driving current through the first bypass path corresponding to the rectified voltage of the second level and the third level,
Wherein the third light emitting diode group receives the drive current through the second bypass path corresponding to a part of the rectified voltage of the fourth level or higher. 10. The method of claim 9,
Further comprising a first diode between an output terminal of the first light emitting diode group and an input terminal of the second light emitting diode group, a second diode between an output terminal of the second light emitting diode group and an input terminal of the third light emitting diode group,
Wherein the first bypass circuit selectively provides the first bypass path to the second light emitting diode group in parallel with the first diode,
The second bypass circuit selectively providing the second bypass path to the third light emitting diode group in parallel with the second diode, 10. The method of claim 9,
Wherein the first bypass circuit provides the first bypass path to the second light emitting diode group corresponding to light emission of the second light emitting diode group and light emission of the second and third light emitting diode groups,
Wherein the second bypass circuit provides the second bypass path to the third light emitting diode group corresponding to light emission of the third light emitting diode group. 12. The method of claim 11,
Wherein the second bypass circuit distributes the driving current in the second bypass path between the first bypass circuit and the third LED group in response to light emission of the second and third LED groups To provide light emitting diode lighting device. 12. The method of claim 11,
Wherein the first bypass circuit regulates the flow of the driving current in response to light emission of the second light emitting diode group,
Wherein the second bypass circuit regulates the flow of the driving current in response to light emission of the third light emitting diode group,
Wherein the first constant current level regulated by the first bypass circuit is lower than the second constant current level regulated by the second bypass circuit. 10. The light emitting diode according to claim 9, wherein the first,
The light emission of the first light emitting diode group corresponding to the rectified voltage higher than the first level and lower than the second level,
The light emission of the second light emitting diode group corresponding to the rectified voltage higher than the second level and lower than the third level,
The light emission of the first and second light emitting diode groups corresponding to the rectified voltage higher than the third level and lower than the fourth level,
The light emission of the third light emitting diode group corresponding to the rectified voltage higher than the fourth level and lower than the fifth level,
Light emission of the second and third light emitting diode groups corresponding to the rectified voltage above the fifth level and below the sixth level, and
Performing light emission of the first to third light emitting diode groups corresponding to the rectified voltage of the sixth level or higher,
The fifth level corresponds to the sum of the second level and the fourth level,
And the sixth level corresponds to a sum of the first level, the second level, and the fourth level. A first light emitting diode group emitting light when a voltage of a first level or higher is applied across both ends;
A bypass circuit for maintaining a normal turn-on state and selectively providing a bypass path of a driving current in parallel to the first light emitting diode group; And
Wherein the light emitting diode emits light when a voltage of a second level or higher than the first level is applied between both ends of the first light emitting diode group and the bypass circuit, 2 light emitting diode group,
The first and second light emitting diode groups emit light corresponding to the rectified voltage of the third level or higher, which is the sum of the first level and the second level,
Wherein the bypass circuit provides the bypass path corresponding to the light emission of the second light emitting diode group corresponding to the rectified voltage of the second level or higher,
Wherein the flow of the driving current through the bypass path is blocked by sensing the driving current corresponding to the rectified voltage to which the voltage of the second level or higher is applied across the bypass circuit. .

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