KR102248088B1 - Apparatus of driving a light emitting device - Google Patents

Abstract

The embodiment relates to a light emitting device driving apparatus for driving a light emitting unit including a plurality of light emitting device arrays connected in series, a rectifier configured to rectify an AC signal to output a rectified signal, detect the voltage level of the rectified signal, and Based on the voltage level of the rectified signal, a driving control unit for controlling the lighting and turning off of the plurality of light emitting device arrays connected in series, between the output terminal of the last light emitting device array of the serially connected light emitting device arrays and the driving control unit A current control unit connected to the light emitting unit for controlling a current flowing through the light emitting unit, and a noise filter connected between the light emitting unit and the rectifying unit to remove high frequency noise included in a rectified signal provided to the light emitting unit do.

Description

Light-emitting element driving device {APPARATUS OF DRIVING A LIGHT EMITTING DEVICE}

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

Due to the development of semiconductor technology, the efficiency of a light emitting diode (LED) has been greatly improved. Accordingly, LEDs have a long lifespan and low energy consumption compared to conventional lighting devices such as incandescent light bulbs and fluorescent lamps, so they are economical and eco-friendly. Due to these advantages, LEDs are currently attracting attention as a light source to replace the backlight of a flat display device such as a traffic light or a liquid crystal display (LCD).

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

The embodiment provides a light emitting device driving apparatus capable of preventing a flicker phenomenon caused by high frequency noise.

The embodiment relates to a light emitting device driving apparatus for driving a light emitting unit including a plurality of light emitting device arrays connected in series, comprising: a rectifier configured to rectify an AC signal to output a rectified signal; A driving control unit that senses the voltage level of the rectified signal and controls the light-emitting element arrays connected in series to be turned on and off based on the detected voltage level of the rectified signal; A current control unit connected between the output terminal of a last light emitting device array among the series-connected light emitting device arrays and the driving control unit, and controlling a current flowing through the light emitting unit; And a noise filter connected between the light emitting part and the rectifying part and removing high frequency noise included in the rectified signal provided to the light emitting part.

The driving control unit includes: a first input pin to which a first output terminal of the rectifying unit is connected; And a second input pin to which a second output terminal of the rectifier is connected, wherein the noise filter is between an output terminal of a last light emitting device array among the serially connected light emitting device arrays and the second input pin of the driving control unit. Can be connected to.

The current controller and the noise filter may be connected in parallel between an output terminal of the last light emitting element array and a second input pin of the driving controller.

The noise filter may be a capacitor.

The current controller may be a resistor.

Channels forming a current path may be formed between the output terminals of the serially connected light emitting device arrays and the driving control unit, and the driving control unit controls the opening and blocking of the channels, so that the plurality of light emitting devices Arrays can be driven.

The embodiment can prevent a flickering phenomenon caused by high frequency noise.

1 is a schematic block diagram of a light emitting module including a light emitting device driving apparatus according to an embodiment.
2 shows an embodiment of the noise filter shown in FIG. 1.
3A shows a current of a light emitting unit driven by the light emitting device driving apparatus of FIG. 1 without a noise filter.
3B shows a current of a light emitting unit driven by the light emitting device driving apparatus according to the embodiment.

Hereinafter, embodiments will be clearly revealed through the accompanying drawings and description of the embodiments. In the description of the embodiment, each layer (film), region, pattern or structure is "on" or "under" of the substrate, each layer (film), region, pad, or patterns. In the case of being described as being formed in, "on" and "under" include both "directly" or "indirectly" formed do. In addition, standards for the top/top or bottom/bottom of each layer will be described based on the drawings.

In the drawings, sizes are exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not fully reflect the actual size. In addition, the same reference numerals denote the same elements throughout the description of the drawings.

1 is a schematic block diagram of a light emitting module 100 including a light emitting device driving apparatus according to an embodiment.

Referring to FIG. 1, the light-emitting module 100 includes a light-emitting unit 101 for generating light and a light-emitting device driving device 102 for driving the light-emitting unit 101.

The light-emitting unit 101 includes a plurality of light-emitting element arrays (D1 to Dn, a natural number of n>1) connected in series.

For example, the light emitting unit 101 may include first to nth light emitting device arrays (D1 to Dn, a natural number of n>1) sequentially connected in series. In FIG. 1, a case of n=4 is shown, and descriptions will be made based on this, but embodiments are not limited thereto.

Each of the plurality of light emitting device arrays D1 to D4 may include one or more light emitting devices. For example, the light emitting device may be a light emitting diode.

When the number of light-emitting elements included in the light-emitting element array is plural, the plurality of light-emitting elements may be connected in series, connected in parallel, or connected in series and in parallel.

The light emitting element driving device 102 controls lighting of the serially connected light emitting element arrays D1 to D4 based on the magnitude of the AC power supply voltage.

The light emitting device driving device 102 includes an AC power supply unit 110, a fuse 120, a rectifying unit 130, a driving control unit 140, a current control unit 150, and a noise filter 160.

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

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, but is not limited thereto. For example, the AC signal Vac may be an AC voltage having 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 rectifying unit 130 and serves to protect the light emitting device driving device 102 from an AC signal having an instantaneous high level. That is, when an AC signal having a high level is instantaneously provided, the fuse 120 is blown, so that the light emitting element driving device 102 may be protected from the AC signal having a high level.

The rectifying unit 130 rectifies the AC signal Vac provided from the AC power supply unit 110 and provides a rectified signal VR according to the rectified result to the light emitting unit 101 and the driving control unit 140. For example, the first output terminal (a) of the rectifying unit 130 may be connected to the positive terminal of the first light emitting element array D1 of the light emitting unit 101, and the second output terminal (b) of the rectifying unit 130 is It may be connected to the negative terminal of the fourth light emitting element array D4 of the light emitting unit 101.

For example, the rectifying unit 130 may full-wave rectify the AC signal Vac and output a rectified signal VR according to a result of the full-wave rectification. Here, the rectified signal VR may be a ripple current obtained by full-wave rectification of the AC signal Vac.

The rectifier 130 may be implemented as a full-wave diode bridge circuit including four diodes BD1, BD2, BD3, and BD4 bridged, but is not limited thereto.

The driving control unit 140 senses the voltage level of the rectified signal VR provided from the rectifying unit 130, and based on the detected voltage level of the rectified signal VR, the serially connected light emitting element arrays D1 to D4 Controls the lighting and turning off.

The driving control unit 140 detects the voltage level of the rectified signal VR, and sequentially drives a plurality of light emitting device arrays D1 to D4 connected in series based on the detected voltage level of the rectified signal VR. can do.

For example, the driving control unit 140 may turn on the light emitting device arrays D1 to D4 in a first order based on a change in the voltage level of the rectified signal VR, and the lighted light emitting device arrays D1 To Dn, a natural number of n>1) may be turned off in an order opposite to the first order. The first order may be the order in which the light emitting device arrays are connected in series, but is not limited thereto.

Channels CH1 to CH4 forming a current path may be formed between the output terminals of each of the light emitting device arrays D1 to D4 connected in series and the driving control unit 140, and the driving control unit 140 is a light emitting device array connected in series. By controlling the opening and blocking of the channels CH1 to CH4 between the output terminals of each of the output terminals D1 to D4 and the driving control unit 140, the plurality of light emitting element arrays D1 to D4 may be sequentially driven.

The driving control unit 140 may compare the voltage level of the rectified signal VR with preset voltage levels LV1 to LV4 and control opening and blocking of the channels CH1 to CH4.

Each of the preset voltage levels LV1 to LV4 may be a voltage capable of driving at least one of the serially connected light emitting device arrays.

For example, the first voltage level LV1 may be a voltage capable of driving one light-emitting device array (eg, D1), and the second voltage level LV2 is two series-connected light-emitting device arrays (eg, D1). To D2), and the third voltage level LV3 may be a voltage capable of driving three serially connected light emitting device arrays (eg, D1 to D3), and a fourth voltage level (LV4) may be a voltage capable of driving four serially connected light emitting device arrays (eg, D1 to D4).

For example, when the rectified signal VR is above the first level LV1 and less than the second level LV2, the driving control unit 140 opens the first and fourth channels CH1 and CH4, and By blocking the second and third channels CH2 and CH3, the first light emitting element array D1 is turned on, and the second to fourth light emitting element arrays D2 to D4 are turned off.

In addition, when the rectified signal VR is at least the second level LV2 and less than the third level LV3, the driving control unit 140 opens the second and fourth channels CH2 and CH4, and By blocking the third channels CH1 and CH3, the first and second light emitting device arrays D1 and D2 are turned on, and the third and fourth light emitting device arrays D3 and D4 are turned off.

In addition, when the rectified signal VR is at least the third level LV3 and less than the fourth level LV4, the driving control unit 140 opens the third and fourth channels CH3 and CH4, and By blocking the second channels CH1 and CH2, the first to third light emitting device arrays D1 to D3 can be turned on and the fourth light emitting device array D4 can be turned off.

In addition, when the rectified signal VR is above the fourth level LV4 and below the maximum level MAX, the driving control unit 140 blocks all of the first to fourth channels CH1 to CH4, thereby All of the fourth light emitting device arrays D1 to D4 may be turned on.

The current control unit 150 is connected between the light emitting unit 101 and the second output terminal b or the reference potential Vss of the rectifying unit 130 and may control a current flowing through the light emitting unit 101.

For example, the current control unit 150 may be connected between the output terminal N4 of the last light emitting device array D4 among the light emitting device arrays D1 to D4 connected in series and the driving control unit 140.

The current controller 150 may be implemented as a passive device such as a resistor, but is not limited thereto, and may be implemented as an active device such as a transistor.

The driving control unit 140 includes a first input pin P1 to which the first output terminal a of the rectifier 130 is connected, and a second input pin P2 to which the second output terminal b of the rectifier 130 is connected. ), channel pins PC1 to PC4 connected to the output terminals N1 to N4 of the light emitting device arrays D1 to D4 connected in series.

The current controller 150 is connected between the output terminal N4 of the last light emitting element array D4 among the light emitting element arrays D1 to D4 connected in series and the second input pin P2 of the driving controller 140. I can.

The noise filter 160 is connected between the light emitting unit 101 and the second output terminal b of the rectifying unit 130, and filtering and removing noise included in the rectified signal VR provided to the light emitting unit 101 do.

For example, the noise filter 160 is between the output terminal N4 of the last light emitting element array D4 among the light emitting element arrays D1 to D4 connected in series and the second input pin P2 of the driving control unit 140. Can be connected.

In addition, for example, the noise filter 160 is between the output terminal N4 of the last light emitting device array D4 among the light emitting device arrays D1 to D4 connected in series and the second input pin P2 of the driving control unit 140. The noise included in the current flowing through the output unit 101 controlled by the current controller 150 may be connected in parallel and may be removed.

In a lighting environment where noise is generated such as a servo motor or a fan, high-frequency noise may be introduced into the AC power supplied through the AC power supply, and the current flowing in the light emitting portion may be affected by such high-frequency noise, and thereby emit light. The part may flicker, and the power consumption of the light emitting part may also change.

Even if high-frequency noise is introduced into the AC power, in the embodiment, noise included in the AC power Vac or the rectified power VR is removed by the noise filter 160, so that the current flowing through the light emitting unit 101 has high-frequency noise. May not be included, thereby preventing the flickering phenomenon of the light emitting unit 101 and preventing a change in power consumption.

2 shows an embodiment of the noise filter 160 shown in FIG. 1. The same reference numerals as in FIG. 1 denote the same configuration, and description of the same configuration is simplified or omitted.

Referring to FIG. 2, the noise filter 160 of FIG. 1 may be implemented with the capacitor 160a of FIG. 2, but is not limited thereto, and may be implemented in the form of a low pass filter capable of removing a high-frequency signal. May be.

In parallel with the current controller 150 between the output terminal N4 of the last light emitting element array D4 among the serially connected light emitting element arrays D1 to D4 and the second input pin P2 of the driving controller 140 It may be a connected capacitor 160a.

The capacitor 160a may have sufficient capacity (eg, 0.5[nF] to 5[nF]) to remove high-frequency noise having a frequency of 5 [kHz] or more.

3A illustrates a current of a light emitting unit driven by the light emitting device driving device without the noise filter 160 of FIG. 1, and FIG. 3B illustrates a current of the light emitting unit driven by the light emitting device driving device according to the embodiment. A noise signal used in the experiment, for example, a pulse signal, may have a magnitude of 1 [kV] and a frequency of 5 [kHz]. V1 and V2 denote the AC power supply voltage, and I1 and I2 denote the current flowing through the light emitting unit.

In the case of FIG. 3A, it can be seen that some distortion 301 occurs in the waveform of the current I1 flowing in the light emitting part due to high frequency noise, and the light emitting part driven by the light emitting element driving device due to this distortion 301 May flicker.

On the other hand, in the case of FIG. 3B, since the high-frequency noise is removed by the filter 160, it can be seen that distortion 301 does not occur in the waveform of the current I2 flowing in the light emitting unit. Flickering does not occur in the light emitting unit driven by this.

Features, structures, effects, and the like described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Further, the features, structures, effects, etc. illustrated in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

110: AC power supply unit 120: fuse
130: rectifier 140: drive control unit
150: current control unit 160: noise filter
160a: capacitor.

Claims (8)

In the light emitting element driving apparatus for driving a light emitting unit including a plurality of light emitting element arrays connected in series,
A rectifying unit including a first output terminal and a second output terminal for rectifying an AC signal and outputting a rectified signal;
A first input pin to which a first output terminal of the rectifier is connected and a second input pin to which a second output terminal of the rectifier is connected, detects a voltage level of the rectified signal, and detects a voltage level of the rectified signal A driving control unit for controlling the lighting of the plurality of light emitting device arrays connected in series based on the light emitting device;
A current controller connected between the output terminal of the last light emitting device array and the second input pin among the serially connected light emitting device arrays, and controlling a current flowing to the light emitting part; And
A noise filter connected between the output terminal of the last light emitting device array and the second input pin among the serially connected light emitting device arrays, and removing high-frequency noise included in the rectified signal provided to the light emitting part. and,
The first input pin is connected to a first light emitting device array among the plurality of light emitting device arrays connected in series,
The noise filter and the current controller are connected in parallel to each other between the output terminal of the last light emitting element array and the second input pin,
Channels forming a current path are formed between the output terminals of the serially connected light emitting device arrays and the driving control unit,
The driving control unit drives the plurality of light emitting device arrays by controlling opening and blocking of the channels. delete delete delete delete delete The method of claim 1,
The noise filter is a capacitor,
The capacity of the capacitor is 0.5[nF] to 5[nF]. The method of claim 1,
The rectifying unit is a light emitting device driving device which is a full-wave diode bridge circuit including four diodes connected to a bridge.

Images