KR20150073386A - Apparatus of driving a light emitting device - Google Patents

Abstract

The present invention relates to an apparatus for driving a light emitting device, which controls a plurality of light emitting device arrays connected in series. The apparatus for driving a light emitting device comprises: a rectifying unit rectifying an alternating signal and outputting a pulsating current signal; and a control unit turning on the light emitting device arrays according to a first sequence based on change of the voltage level of the pulsating current signal during a first cycle section of the pulsating current signal, and turning on the light emitting device arrays according to a second sequence based on change of the voltage level of the pulsating current signal during a first cycle section of the pulsating current signal, wherein the first sequence turns on the light emitting device arrays connected in series, and the second sequence is reversed to the first sequence.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The embodiment relates to a light emitting element driving apparatus for driving a light emitting element.

Due to the development of semiconductor technology, the efficiency of light emitting diodes (LEDs) has been greatly improved. Accordingly, the LED has an advantage that it is economical as well as environmentally friendly because it has a longer life and less energy consumption than conventional lighting devices such as incandescent lamps and fluorescent lamps. Due to these advantages, LEDs are now attracting attention as a light source to replace backlights of flat panel display devices such as traffic lights and liquid crystal displays (LCDs).

In general, when an LED is used as a lighting device, a plurality of LEDs are connected in series or in parallel, and lighting and lighting of the LED are controlled by a light-emitting element controller. As described above, the light-emitting element control device for controlling a plurality of LEDs generally rectifies an alternating current (AC) voltage and controls turning on and off of a plurality of LEDs by a rectified ripple voltage.

The embodiment provides a light emitting element driving apparatus capable of uniformizing the lifetime of series-connected light emitting element arrays.

A light emitting device driving apparatus for controlling a plurality of light emitting device arrays connected in series according to an embodiment includes a rectifying unit for rectifying an AC signal and outputting a pulsating signal; And a control circuit for controlling the light emitting element arrays according to a first order based on a change in the voltage level of the pulse signal (VR) during a first period of the pulse signal, And a control unit for lighting the light emitting element arrays according to a second order based on a change in the voltage level of the light emitting element arrays in the first order, Is the reverse of the first order.

The controller may turn off the light emitting device arrays turned on during the first period in an order opposite to the first order.

The controller may turn off the light emitting device arrays turned on during the second period in the reverse order of the second order.

The first order may be a sequential serial connection order of the light emitting device arrays.

The first period may be an odd period of the pulse signal, and the second period may be an even period of the pulse signal.

Wherein the control unit comprises: a switch connected in parallel to each of the plurality of light emitting device arrays; And a switching control unit for comparing the voltage level of the pulse current signal with each of predetermined voltage levels and controlling a switch connected in parallel to each of the light emitting element arrays based on the comparison result.

The controller may turn on all of the light emitting device arrays in the first order in a period in which the level of the pulse signal rises.

The controller may turn off the light emitting device arrays which are all turned on in a period in which the level of the pulse signal falls, in the order opposite to the first order.

The controller may light up all of the light emitting device arrays according to the second order in a period in which the level of the pulse signal rises.

The light emitting element arrays all turned on in the interval in which the level of the pulse current signal falls can be turned off in the order opposite to the second order.

The light emitting device driving apparatus may further include an alternating current (AC) power source for providing the AC signal to the rectifying unit.

Embodiments can make the lifetime of the light emitting device arrays connected in series uniform, and can increase the lifetime of the light emitting device array.

Figure 1 shows a schematic block diagram of a light emitting module according to an embodiment.
2A is a waveform diagram of an AC signal supplied from the AC power supply unit shown in FIG.
2B shows a pulse signal output from the rectifying section shown in FIG.
FIG. 3 shows an embodiment of the light emitting device driving unit shown in FIG.
4A shows the current path of the light emitting device arrays during the first period of the pulse signal.
4B shows light emitting device arrays which are turned on during a first period of a pulse signal.
5A shows the current path of the light emitting device arrays during the second period of the pulse current signal.
FIG. 5B shows light emitting device arrays which are turned on during the second period of the pulse signal.
Fig. 6 shows an embodiment of the control unit shown in Fig.
FIG. 7 shows the lighting of the light emitting device arrays according to the switching operation of the first through fourth switches shown in FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. In the description of the embodiments, it is to be understood that each layer (film), region, pattern or structure may be referred to as being "on" or "under" a substrate, each layer It is to be understood that the terms " on "and " under" include both " directly "or" indirectly " do. In addition, the criteria for the top / bottom or bottom / bottom of each layer are described with reference to the drawings.

In the drawings, dimensions are exaggerated, omitted, or schematically illustrated for convenience and clarity of illustration. Also, the size of each component does not entirely reflect the actual size. The same reference numerals denote the same elements throughout the description of the drawings. Hereinafter, a light emitting element driving apparatus according to an embodiment will be described with reference to the accompanying drawings.

1 shows a schematic block diagram of a light emitting module 100 according to an embodiment.

Referring to FIG. 1, the light emitting module 100 includes a light emitting unit 101 that generates light, and a light emitting device driver 102 that controls the operation of the light emitting unit 101.

The light emitting unit 101 includes a plurality of light emitting device arrays D1 to Dn, n> 1, which are connected in series.

For example, the light emitting unit 160 may include first through n-th light emitting device arrays (D1 through Dn, n> 1) sequentially connected in series.

Each of the plurality of light emitting device arrays D1 to Dn and n> 1 may include one or more light emitting devices LD1 to LDM and a natural number of M≥1.

When the number of the light emitting devices included in the light emitting device array is plural, the plurality of light emitting devices (LD1 to LDM, natural number of M> 1) may be connected in series, parallel, or in series and parallel.

The light emitting element driver 102 controls lighting of the light emitting element arrays D1 to Dn, where n> 1.

The light emitting device driver 102 may include an AC power source 110, a fuse 120, a rectifier 130, and a controller 140.

The AC power supply unit 110 provides the AC signal Vac to the rectifying unit 130.

FIG. 2A shows a waveform diagram of an AC signal Vac supplied from the AC power source unit 110 shown in FIG.

Referring to FIG. 2A, the AC signal Vac may be a sine wave or a cosine wave having a maximum value of MAX and a minimum value of MIN. However, the present invention is not limited thereto. For example, the ac signal Vac may be an ac voltage having an effective value of 100 to 200 volts (V) and a frequency of 50 Hz to 60 Hz, but is not limited thereto.

The fuse 120 is connected between the AC power supply unit 110 and the rectification unit 130 and protects the light emitting device driving unit 102 from AC signals having a high level instantaneously. That is, when the alternating current signal having an instantaneously high level is provided, the light emitting element driving part 102 can be protected from the alternating signal having a high level due to breaking of the fuse 120.

The rectifying unit 130 rectifies the AC signal Vac supplied from the AC power supply unit 110 and outputs a ripple current (VR) according to the rectified result.

FIG. 2B shows the pulse signal VR output from the rectifier 130 shown in FIG. Referring to FIG. 2B, the rectifying unit 130 may full-wave rectify the AC signal Vac shown in FIG. 2A and output a pulsating signal VR as shown in FIG. 2B. That is, the pulsating signal VR may be a signal in which the AC signal is full-wave rectified.

The control unit 140 controls to turn on and off the light emitting element arrays D1 to Dn, where n> 1, of the light emitting unit 101 in series, based on the pulse signal VR supplied from the rectifying unit 130 do.

The controller 140 controls the light emitting element arrays (light emitting element arrays) according to the first order during the first period T1 of the pulsating signal VR based on the change in the voltage level of the pulse signal VR supplied from the rectifying unit 130 D1 to Dn, n > 1).

Also, the controller 140 may turn off the light emitting device arrays D1 through Dn, which are lighted in the first period T1, in the order opposite to the first order.

For example, after the control unit 140 lights the light emitting device arrays D1 through Dn, n> 1 in the first order during the first period T1, the light emitting device arrays D1 through Dn , n > 1) can be extinguished in the reverse order of the first order.

At this time, after the control unit 140 lights all of the light emitting device arrays D1 to Dn (natural number of n> 1) according to the first order, the light emitting device arrays D1 to Dn, n > 1) can be turned off.

The control unit 140 turns on the light emitting element arrays D1 to Dn and n> 1 as a natural number in the second order during the second period T2 based on the change in the voltage level of the pulse signal VR .

Also, the controller 140 may turn off the light emitting device arrays (D1 through Dn, n> 1), which are turned on during the second period T2, in the order opposite to the second order.

For example, after the control unit 140 lights the light emitting device arrays D1 through Dn, n> 1 in the second order during the second period T2, the light emitting device arrays D1 through Dn , n> 1) can be extinguished in the reverse order of the second order.

At this time, the controller 140 turns on the light emitting device arrays D1 to Dn, n> 1 in the second order, and then the light emitting device arrays D1 to Dn, n > 1) can be turned off.

For example, the first period T1 may be an odd period section of the pulse signal VR, and the second period T2 may be an even period section of the pulse signal VR.

Here, the "first order" may mean the order in which the light emitting device arrays (D1 to Dn, n> 1) connected in series are lit

For example, the first order may be a sequential serial connection order of the first through Nth light emitting device arrays (D1 through Dn, n> 1), and the second order may be a reverse order of the first order . The first period T1 and the second period T2 may be adjacent to each other.

The control unit 140 controls the first to Nth light emitting device arrays D1 to Dn and n> 1 to be turned on and off during each period of the pulse signal VR provided from the rectifying unit 130, The first through Nth light emitting device arrays D1 through Dn, natural numbers of n >

FIG. 3 shows an embodiment of the light emitting device driver 102 shown in FIG.

The same reference numerals as those in FIG. 1 denote the same components, and a description of the same components will be simplified or omitted. Although FIG. 3 shows four light emitting device arrays D1 to D4 and is described based on this, the number of light emitting device arrays is not limited to this.

3, the light emitting device driving unit 102 includes an AC power source 110, a fuse 120, a rectifying unit 130A, and a controller 140. Referring to FIG.

The rectifier 130A of FIG. 3 may be implemented as a radio-diode bridge circuit including four diodes BD1, BD2, BD3, and BD4.

The light emitting element arrays D1 to D4 may be electrically connected to each other in series.

The control unit 140 senses the level of the pulse signal VR supplied from the rectifying unit 130 and during the first period T1 of the pulse signal VR based on the level of the pulse signal VR, (Natural numbers of D1 to Dn, n> 1) in accordance with the order of the light emitting element arrays D1 to Dn and n> 1 are turned off in the reverse order of the first order have.

The controller 140 also controls the light emitting element arrays D1 to Dn, n > 1 in accordance with the second order during the second period T2 of the pulsating signal VR based on the level of the pulse signal VR sensed Natural number) and light-emitting element arrays (natural numbers of D1 to Dn, n> 1) which are lighted can be turned off in the reverse order of the second order. At this time, the level of the pulse signal to be sensed may be the voltage level of the pulse signal.

4A shows the current path of the light emitting element arrays D1 to D4 during the first period T1 of the pulsating signal VR and FIG. 4B shows the current path of the light emitting element arrays D1 to D4 during the first period of the pulsating signal VR. Represent arrays D1 to D4.

Referring to FIGS. 4A and 4B, the controller 140 determines whether the pulse signal VR is at the first level LV1 or more at the intervals t1 to t2 and t7 to t8 where the pulsating signal VR is higher than the first level LV1 and lower than the second level LV2. The first current path (1) between the rectification part 130 and the light emitting element arrays D1 to D4 can be formed so that current flows only through the light emitting element array D1.

The controller 140 also controls the first and second light emitting device arrays D1 and D2 in the periods t2 to t3 and t6 to t7 in which the pulse signal VR is higher than the second level LV2 and lower than the third level LV3 The second current path (2) between the rectification part 130 and the light emitting element arrays D1 to D4 can be formed so that the current flows only through the light emitting element arrays D1 to D4.

The controller 140 also controls the first to third light emitting device arrays D1 (D1 to D6) in the periods t3 to t4 and t5 to t6 in which the pulse signal VR is higher than the third level LV3 and lower than the fourth level LV4 The third current path 3 may be formed between the rectification part 130 and the light emitting element arrays D1 to D4 so that the current flows only through the light emitting element arrays D1 to D4.

The controller 140 also controls the first to fourth light emitting device arrays D1 to D4 at intervals t4 to t5 where the pulse signal VR is equal to or greater than the fourth level LV4 and equal to or less than the maximum level MAX (4) between the rectifying part 130 and the light emitting element arrays D1 to D4 so that the current flows in both the rectifying part 130 and the light emitting element arrays D1 to D4.

5A shows a current path of the light emitting element arrays D1 to D4 during the second period T2 of the pulsating signal VR and FIG. 5B shows a current path of the light emitting element arrays D1 to D4 during the second period of the pulsating signal VR. Represent arrays D1 to D4.

5A and 5B, the control unit 140 determines whether the pulse signal VR is at the first level LV1 or more and the second level LV2 or less at the time t9 to t10 and t15 to t16, The fifth current path 5 may be formed between the rectification part 130 and the light emitting element arrays D1 to D4 so that current flows only through the light emitting element array D4.

The controller 140 also controls the fourth and third light emitting device arrays D4 to D15 in the periods t10 to t11 and t14 to t15 in which the pulse signal VR is higher than the second level LV2 and lower than the third level LV3 The current path between the rectification part 130 and the light emitting element arrays D1 to D4 can be formed so that the current flows only through the light emitting element arrays D1 to D4.

The controller 140 also controls the second to fourth light emitting device arrays D2 to D14 in the sections t11 to t12 and t13 to t14 in which the pulse signal VR is higher than the third level LV3 and lower than the fourth level LV4 The third current path 7 between the rectification part 130 and the light emitting element arrays D1 to D4 can be formed so that the current flows only through the light emitting element arrays D1 to D4.

The controller 140 also controls the first through fourth light emitting device arrays D1, D2, D3, and D4 in the period t12 to t13 in which the pulse signal VR is higher than the fourth level LV4 and lower than the highest level MAX (8) between the rectifying part 130 and the light emitting element arrays D1 to D4 so that current flows through the rectifying part 130 and the light emitting element arrays D1 to D4.

FIG. 6 shows an embodiment of the control unit 140 shown in FIG.

Referring to FIG. 6, the controller 140 may include a switching controller 142 and a plurality of switches SW1 to SWn, where n is a natural number.

The switching control unit 142 is electrically connected to both ends a and b of the rectifying unit 130A and senses the voltage level of the pulse signal VR output from the rectifying unit 130A and outputs a control signal (C1 to Cn, n > 1).

The switching controller 142 may compare the voltage level of the pulsating signal VR with preset voltage levels and control the switches SW1 to SWn, n> 1 as a natural number based on the comparison result.

Each of the predetermined voltage levels LV1 to LV4 may be a voltage capable of driving at least one of the light emitting device arrays connected in series. For example, the first voltage level LV1 may be a voltage capable of driving one light emitting element array, the second voltage level LV2 may be a voltage capable of driving two series-connected light emitting element arrays, The third voltage level LV3 may be a voltage capable of driving three series-connected light emitting device arrays, and the fourth voltage level LV4 may be a voltage capable of driving four series-connected light emitting device arrays.

For example, the switching control unit 142 senses the points of time when the voltage level of the pulsating signal VR is equal to each of the predetermined voltage levels, and outputs control signals (C1 through Cn, n> 1) Can be output.

For example, the switching control unit 142 senses the first to fourth levels LV1 to LV4 of the voltage level of the pulsating signal VR during the first period T1, And the switches SW1 to SWn, natural numbers of n > 1 to form a current path as shown in Fig. 5B.

The switching control unit 142 includes a voltage adjusting unit for adjusting the voltage level of the pulsating signal VR and outputting a signal whose voltage level is adjusted, a clock generating unit for generating a clock signal, The counting unit counts the clock signal generated by the clock generating unit until a predetermined voltage level (e.g., LV1 to LV2) becomes equal to the predetermined voltage levels (e.g., LV1 to LV2).

The voltage regulator may be implemented as a voltage divider composed of resistors connected in series at both ends of the current unit 130A in order to distribute the voltage supplied from both ends a and b of the rectification unit 130A at a constant ratio. At this time, the voltage adjusted by the voltage adjusting unit may be a voltage applied to at least one of the serially connected resistors.

The switching control section 142 can control the switches SW1 to SWn, a natural number of n> 1 based on the number of clocks counted by the counting section.

Each of the plurality of switches SW1 to SWn and n> 1 is connected in parallel with a corresponding one of the plurality of light emitting device arrays D1 to Dn, n> 1.

That is, the control unit 140 may include switches SW1 to SWn, n> 1, which are connected in parallel with each of the plurality of light emitting device arrays D1 to Dn and n> 1.

For example, the first switch SW1 may be connected in parallel with the first light emitting device array D1, the second switch SW2 may be connected in parallel with the second light emitting device array D2, the third switch SW3, The fourth switch SW4 may be connected in parallel with the third light emitting device array D3 and the fourth switch SW4 may be connected in parallel with the fourth light emitting device array D4.

Each of the plurality of switches SW1 to SWn and n is a natural number is turned on in response to any one of the control signals (C1 to Cn, c> 1) output from the switching control unit 142, (turn on) or turn off (off).

Each of the plurality of switches (SW1 to SWn, natural number of n> 1) may be implemented as a bipolar transistor or a field effect transistor.

If the switches SW1 to SWn and n> 1 are implemented as bipolar transistors, the control signals C1 to C4 output from the switching controller 142 may be input to the base of the bipolar transistor.

Or if the switches SW1 to SWn and n> 1 are implemented in the form of a field effect transistor, the control signals C1 to C4 output from the switching control section 142 are input to the gate of the field effect transistor .

Although not shown in FIG. 6, in order to control the current flowing between the switching control unit 142 and the switches SW1 to SWn, the natural number being n> 1, the switching control unit 142 and the switches SW1 to SWn, n> 1 A current limiting resistor may be connected. Further, a resistor may be connected between two adjacent light emitting device arrays D1 to D4 to control a current flowing in the light emitting device arrays connected in series.

In FIG. 6, four light emitting device arrays D1 to D4, four switches SW1 to SW4, and four control signals C1 to C4 are illustrated, but the embodiment is not limited thereto.

FIG. 7 shows the lighting of the light emitting device arrays according to the switching operation of the first through fourth switches shown in FIG.

Referring to FIG. 7, the switching controller 142 may output control signals C1 to C4 for controlling the switches SW1 to SW4.

For example, the switch control unit 142 may detect a change in the voltage level of the pulse signal VR and output the control signals C1 to C4 based on the voltage level of the pulse signal VR sensed.

The switches SW1 to SW4 may operate as follows by the control signals C1 to C4 output from the switching control unit 142 during the first period T1 of the pulse signal VR.

For example, the first switch SW1 may be turned off at a time t1 when the pulse signal VR becomes equal to the first level LV1 in a period in which the level of the pulse signal VR rises, The first to fourth switches SW2 to SW4 may be turned on and the first light emitting device array D1 may be turned on.

The first switch SW1 may be in a turned off state in the period from t1 to t2 where the pulse signal VR is higher than the first level LV1 and lower than the second level LV2, The first to fourth light emitting element arrays D2 to D4 may be turned off and the first to fourth light emitting element arrays D2 to D4 may be turned off .

The first and second switches SW1 and SW2 are turned off at a time point t2 when the pulsating current signal VR becomes equal to the second level LV2 in a period in which the level of the pulsating signal VR rises And the third and fourth switches SW3 and SW4 can be turned on and the first and second light emitting device arrays D1 and D2 can be turned on.

The first and second switches SW1 and SW2 may be turned off in a period t2 to t3 where the pulse signal VR is higher than the second level LV2 and lower than the third level LV3, 3 and the fourth switches SW3 and SW4 may be in a turned on state and the first and second light emitting device arrays D1 and D2 may be in an on state and the third and fourth light emitting device arrays (D3, D4) may be off.

The first to third switches SW1 to SW3 are turned off at a time point t3 when the pulsating current signal VR becomes equal to the third level LV3 in a period in which the level of the pulse signal VR rises And the fourth switch SW4 may be turned on and the first through third light emitting device arrays D1, D2, and D3 may be turned on.

The first to third switches SW1 to SW3 may be turned off in a period t3 to t4 where the pulse signal VR is higher than the third level LV3 and lower than the fourth level LV4, The fourth switch SW4 may be turned on and the first through third light emitting device arrays D1, D2 and D3 may be turned on and the fourth light emitting device array D4 may be turned off. .

The first to fourth switches SW1 to SW4 can be turned off at a time point t4 when the pulse signal VR becomes equal to the fourth level LV4 and the first to fourth light emitting element arrays D1 to D4 may be turned on.

The first to fourth switches SW1 to SW4 may be all turned off in the period from t4 to t5 where the pulsating signal VR is equal to or higher than the fourth level LV4 and equal to or lower than the highest level MAX, 1 to the fourth light emitting device arrays D1 to D4 may all be in a lighted state.

The first to third switches SW1 to SW3 are turned off at a time point when the pulsating current signal VR falls below the fourth level LV4 in a period in which the level of the pulse signal VR falls, The fourth switch SW4 can be turned on and the fourth light emitting element array D4 can be turned off.

The first to third switches SW1 to SW6 are turned on in the period t5 to t6 in which the pulse signal VR is higher than the third level LV3 and lower than the fourth level LV4 in the period in which the level of the pulsating signal VR falls, SW3 may be in a turned-off state, the fourth switch SW4 may be in a turned-on state, the fourth light emitting element array D4 may be in an unlit state, and the first to third light emitting element arrays (D1, D2, D3) may be in a lighted state.

The first and second switches SW1 and SW2 are turned on at a time point (for example, immediately after t6) at which the pulsating current signal VR becomes lower than the third level LV3 in a period in which the level of the pulsating signal VR falls. The third and fourth switches SW3 and SW4 can be turned on and the third and fourth light emitting device arrays D3 and D4 can be turned off.

The first and second switches SW1 and SW2 may be turned off in the period t6 to t7 where the pulse signal VR is higher than the second level LV2 and lower than the third level LV3, The third and fourth switches SW3 and SW4 may be turned on and the third and fourth light emitting device arrays D3 and D4 may be turned off and the first and second light emitting device arrays (D1, D2) may be in a lighted state.

The first switch SW1 may be turned off at a time point at which the pulsating current signal VR falls below the second level LV2 (for example, immediately after t7) in the period in which the level of the pulsating signal VR falls, To fourth switches SW2 to SW4 may be turned on and the second to fourth light emitting device arrays D2, D3, and D4 may be turned off.

The first switch SW1 may be in a turned off state in a period from t7 to t8 where the pulse signal VR is higher than the first level LV1 and lower than the second level LV2, The first to fourth light emitting element arrays D2 to D4 may be in an unlit state and the first light emitting element array D1 may be in an illuminated state .

(0 to t1, t8 to t9, and t16) in which the pulse signal VR is higher than the lowest level (for example, 0) and lower than the first level LV1 in the period in which the level of the pulse signal VR rises or falls, The first to fourth light emitting device arrays D1 to D4 may be turned off.

The light emitting element arrays D1 to D4 are all turned on in the first order during the first period T1 of the pulse signal VR and the light emitting element arrays D1 to D4 are turned on in the reverse order of the first order It can be seen that it goes out.

The switches SW1 to SW4 may operate as follows by the control signals C1 to C4 output from the switching control unit 142 during the second period T2 of the pulsating signal VR.

The first to third switches SW1 to SW3 may be turned on at a time point t9 where the pulse current signal VR is equal to the first level LV1 in the rising period of the pulse signal VR, The fourth light emitting element array SW4 may be turned off, and the fourth light emitting element array D4 may be turned on.

The first to third switches SW1 to SW3 may be turned on in a period from t9 to t10 where the pulse signal VR is higher than the first level LV1 and lower than the second level LV2, The fourth switch SW4 may be in a turned off state and the fourth light emitting diode array D4 may be in a lighted state and the first to third light emitting diode arrays D1 to D3 may be in an unlit state have.

The first and second switches SW1 and SW2 can be turned on at a time point t10 when the pulse signal VR becomes equal to the second level LV2 in the rising period of the pulse signal VR, 3 and the fourth switches SW3 and SW4 may be turned off and the third and fourth light emitting device arrays D3 and D4 may be turned on.

The first and second switches SW1 and SW2 may be turned on in a period t10 to t11 where the pulse signal VR is higher than the second level LV2 and lower than the third level LV3, 3 and the fourth switches SW3 and SW4 may be in a turned off state and the third and fourth light emitting device arrays D3 and D4 may be in a lighted state and the first and second light emitting device arrays D1 and & D2 may be off.

The first switch SW1 can be turned on at a time point t11 when the pulse signal VR becomes equal to the third level LV3 in the rising period of the pulse signal VR, The switches SW2 to SW4 may be turned off and the second to fourth light emitting device arrays D2 to D4 may be turned on.

The first switch SW1 may be in a turned-on state in the period t11 to t12 where the pulse signal VR is higher than the third level LV3 and lower than the fourth level LV4, The first to fourth light emitting element arrays D2 to D4 may be in the turned on state and the first light emitting element array D1 may be in the turned off state .

The first to fourth switches SW1 to SW4 may be turned off at a time t12 when the pulse signal VR becomes equal to the fourth level LV4 in the rising period of the pulse signal VR And the first to fourth light emitting device arrays D1 to D4 may all be lighted.

The first to fourth switches SW1 to SW4 may be all turned off in the period t12 to t13 where the pulsating signal VR is higher than the fourth level LV4 and lower than the highest level MAX, 1 to the fourth light emitting device arrays D1 to D4 may all be in a lighted state.

The first switch SW1 may be turned on at a point of time when the pulse signal VR falls below the fourth level LV4 in a period in which the pulse signal VR falls, The switches SW2 to SW4 may be turned off and the first light emitting device array D1 may be turned off.

The first switch SW1 may be in a turned-on state in the period t13 to t14 where the pulsating signal VR is higher than the third level LV3 and lower than the fourth level LV4, The first to fourth light emitting element arrays D2 to D4 may be in a turned-on state, and the first to fourth light emitting element arrays D2 to D4 may be in a turned-on state .

The first and second switches SW1 and SW2 are turned on at a time point when the pulsating current signal VR is lower than the third level LV3 in a period in which the level of the pulsating signal VR falls, The third and fourth switches SW3 and SW4 can be turned on and the first and second light emitting device arrays D1 and D2 can be turned off.

The first and second switches SW1 and SW2 may be turned off in the period t14 to t15 where the pulse signal VR is higher than the second level LV2 and lower than the third level LV3, 3 and the fourth switches SW3 and SW4 may be turned on and the first and second light emitting device arrays D1 and D2 may be in an unlit state and the third and fourth light emitting device arrays (D3, D4) may be in a lighted state.

The first switch SW1 may be turned off at a time point at which the pulsating signal VR falls below the second level LV2 (for example, immediately after t15) in the period in which the level of the pulse signal VR falls, The first through fourth switches SW2 through SW4 may be turned on and the first through third light emitting device arrays D1, D2, and D3 may be turned off.

The first switch SW1 may be in a turned off state in a period from t7 to t8 where the pulse signal VR is higher than the first level LV1 and lower than the second level LV2, The first to third light emitting device arrays D2 to D4 may be in the unlit state and the fourth light emitting device array D4 may be in the turned on state .

The light emitting element arrays D1 to D4 are all turned on in the second order during the second period T1 of the pulse signal VR and the light emitting element arrays D1 to D4 are turned on in the reverse order of the second order It can be seen that it goes out.

7, during the first period T1 of the pulsating signal VR, the first light emitting device array D1, the second light emitting device array D2, the third light emitting device array D3, and the fourth And the light emitting element array D4 are turned on in the order of a long time.

On the other hand, during the second period T2 of the pulse signal VR, the fourth light emitting device array D4, the third light emitting device array D3, the second light emitting device array D2, and the first light emitting device array D1) is long.

In the embodiment, by changing the order of the light emitting element arrays to be turned on during the first period T1 and the second period T2, the time deviations of the respective light emitting element arrays can be reduced.

Since each of the light emitting element arrays reduces variations in lighting time, the embodiment can make the lifetime of the light emitting element arrays connected in series uniform and increase the lifetime of the light emitting element array.

The features, structures, effects and the like described in the embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments can be combined and modified by other persons having ordinary skill in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

110: AC power supply unit 120: Fuse
130: rectification part 140:
102: light emitting portion.

Claims (11)

1. A light emitting element driving apparatus for controlling a plurality of light emitting element arrays connected in series,
A rectifier for rectifying the AC signal and outputting a pulsating signal; And
Wherein the light emitting element arrays are turned on according to a first sequence based on a change in the voltage level of the pulse current signal during a first period of the pulse current signal and a change in voltage level of the pulse current signal during a second period of the pulse current signal And a control unit for lighting the light emitting device arrays according to a second order based on the light emitting device array,
Wherein the first order is a sequence in which the plurality of light emitting element arrays connected in series are lit, and the second order is a sequence opposite to the first order. The apparatus of claim 1,
And turns off the light emitting element arrays turned on during the first period in an order opposite to the first order. The apparatus of claim 1,
And turns off the light emitting device arrays turned on during the second period in an order opposite to the second order. The method according to claim 1,
Wherein the first order is a sequential serial connection order of the light emitting device arrays. The method according to claim 1,
Wherein the first period section is an odd period section of the pulse signal and the second period section is an even period section of the pulse signal. The apparatus of claim 1,
A switch connected in parallel to each of the plurality of light emitting device arrays; And
And a switching control unit for comparing the voltage level of the pulse current signal with each of predetermined voltage levels and for controlling a switch connected in parallel to each of the light emitting element arrays based on the comparison result. 3. The apparatus of claim 2,
Wherein the light emitting element arrays are all turned on according to the first order in a period in which the level of the pulse signal rises. 8. The apparatus of claim 7,
And turns off the light emitting element arrays, all of which are turned on in a period in which the level of the pulse current signal falls, in an order opposite to the first order. 3. The apparatus of claim 2,
Wherein the light emitting element arrays are all turned on according to the second order in a period in which the level of the pulse current signal rises. 10. The method of claim 9,
Wherein the light emitting element arrays are all turned off in an order opposite to the second order in a period in which the level of the pulse signal falls. The method according to claim 1,
And an AC power supply unit for supplying the AC signal to the rectifying unit.

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