KR101435854B1 - Apparatus for driving light emitting diode - Google Patents

Abstract

The present invention relates to a light emitting diode driving apparatus, and more particularly, to a light emitting diode driving apparatus capable of continuously driving a light emitting diode. The present invention relates to a rectifying unit for rectifying an AC power supply to supply a pulsating voltage; A light emitting unit connected to the rectifying unit and including a plurality of light emitting diodes connected in series, the light emitting unit including two or more groups; A capacitor connected in parallel with at least two groups of the light emitting units; And at least one group of the light emitting units is selectively driven according to the magnitude of the pulsating voltage, and when the pulsating voltage is lower than the operating voltage of the light emitting unit, the capacitors connected to at least one group of the light emitting units And a drive control unit for driving at least one group of the group of light emitting units connected in parallel with the capacitor using a discharge current.

Description

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

The present invention relates to a light emitting diode driving apparatus, and more particularly, to a light emitting diode driving apparatus capable of continuously driving a light emitting diode.

Recently, light emitting diodes (LEDs) having advantages such as efficiency, color diversity, and design autonomy have been attracting attention as a light source of illumination .

A light emitting diode is a semiconductor device which emits light when a voltage is applied in a forward direction, has a long lifetime, low power consumption, and has electrical, optical, and physical characteristics suitable for mass production.

In order to effectively use such a light emitting diode as a light source of illumination, a driving system capable of driving with a commercial AC power supply is required.

SUMMARY OF THE INVENTION The present invention provides a light emitting diode driving apparatus capable of continuously driving a light emitting diode.

According to an aspect of the present invention, there is provided a rectifying unit for rectifying an alternating-current power supply to supply a pulsating voltage; A light emitting unit connected to the rectifying unit and including a plurality of light emitting diodes connected in series, the light emitting unit including two or more groups; A capacitor connected in parallel with at least two groups of the light emitting units; And at least one group of the light emitting units is selectively driven according to the magnitude of the pulsating voltage, and when the pulsating voltage is lower than the operating voltage of the light emitting unit, the capacitors connected to at least one group of the light emitting units And a drive control unit for driving at least one group of the group of light emitting units connected in parallel with the capacitor using a discharge current.

Here, the drive control section may control to charge the capacitor in a phase state including a peak portion of the ripple voltage.

The light emitting portion includes a first group and a second group connected in parallel with the capacitor; And a third group connected to the second group, and in some cases, a fourth group connected to the third group.

The drive control unit may cause the light emitting diodes belonging to the first group to be driven by the discharge current of the capacitor.

Further, the drive control section may control the first group, the second group, and the third group to emit light in a phase state including a peak portion of the pulsating voltage.

At this time, the charging voltage of the capacitor may be larger than the operating voltage of the first group.

Here, the drive control unit may include at least one switch for controlling the flow of electric current to selectively drive at least one of the first group, the second group, and the third group; And a control circuit for controlling the switch.

The switch includes a first switch for allowing current to flow through the capacitor and the first group; And a second switch for allowing current to flow through the first group, the second group, and the third group.

The driving control unit may further include a dimming control unit capable of adjusting the brightness of the light emitting unit.

On the other hand, a circuit protection portion is connected to the capacitor to protect the light emitting portion and the circuit from an overcurrent or an overvoltage. Such a circuit protection portion may include a zener diode or a TVS chip.

Depending on the magnitude of the pulsating voltage, a current loop in which two groups connected in parallel with the capacitor emit light can be formed as the circuit is driven.

Further, the drive control section can control the charge voltage of the capacitor within a voltage range lower than the maximum charge voltage of the capacitor.

The driving control unit may further include a constant current circuit connected to the light emitting unit.

The present invention has the following effects.

First, in an LED driving apparatus directly driven by an AC power source, it is possible to continuously drive without a discontinuous section of a light emitting diode light, thereby improving flicker.

Such continuous driving includes a capacitor, and a constant output can be controlled by adjusting the control voltage of the dimming control unit according to the input voltage.

At this time, since the charging and discharging voltage or charge amount of the capacitor can be controlled to be constantly lower than the maximum capacity of the capacitor, the lifetime of the capacitor may not be limited.

Furthermore, since the dimming control section is implemented at the common reference potential, the circuit configuration can be simply configured.

1 is a circuit diagram showing an example of a light-emitting diode driving apparatus.
Figures 2a and 2b, 3a and 3b, 4a and 4b, 5a and 5b, 6a and 6b, 7a and 7b and 8a and 8b show the magnitude and phase of the ripple voltage Fig. 2 shows the operation and waveform of the circuit of Fig.
9 is a circuit diagram showing another example of the LED driving apparatus.
10A and 10B, Figs. 11A and 11B, Figs. 12A and 12B, Figs. 13A and 13B and Figs. 14A and 14B are diagrams showing operation and waveforms of the circuit of Fig. 9 according to the magnitude and phase of the ripple voltage to be.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

As shown in Fig. 1, the light emitting diode driving apparatus includes a rectifying section 20 that rectifies the alternating-current power supply 10 and outputs a pulsating voltage. The rectifying unit 20 may include a bridge diode for full-wave rectifying the AC power source 10.

The light emitting unit 30 includes a plurality of light emitting diodes connected in series and driven by the pulsating voltage. The light emitting unit 30 is divided into at least two groups 31, 32, 33, and 34.

At least two groups of the group of the light emitting units 30 are connected in parallel with the capacitor C1. Diode D1 may be coupled to capacitor C1 to configure the current flow.

1 shows a light emitting unit 30 including four groups. That is, the light emitting unit 30 including the first group 31 (Group 1), the second group 32 (Group 2), the third group 33 (Group 3), and the fourth group 34 (Group 4) However, it may include two groups or four or more groups as the case may be.

The driving control unit 40 may selectively drive at least one group of the groups of the light emitting units 30 according to the magnitude of the pulsating current passing through the rectifying unit 20. [

When the pulse voltage is lower than the operating voltage of the light emitting unit 30, the driving control unit 40 controls the light emitting unit 30 using the discharging current of the capacitor C1 connected to at least one group of the light emitting unit 30. [ 30) may be driven.

That is, when the pulsating voltage is lower than the operating voltage of the light emitting unit 30, any one or more groups of the group of the light emitting units 30 connected in parallel with the capacitor C1 may emit light.

1, a first group 31 and a second group 32 connected in parallel with the capacitor C1, for example, when the pulsating voltage is lower than the operating voltage of the light emitting unit 30, The light emitting diodes belonging to the first group 31 can be driven. That is, the first group 31 of the light emitting portions 30 may be included in the discharge path of the capacitor C1.

Therefore, in driving the light emitting portion 30 including the plurality of groups 31, 32, 33, and 34, even when the pulsating voltage is lower than the operating voltage of any one group of the light emitting portions 30 The light emitting unit 30 can be continuously driven without a discontinuous section of light by the light emitting unit 30. In this case,

At this time, the drive control unit 40 can control to charge the capacitor C1 in the phase state including the peak portion of the pulsating voltage. The capacitor C1 can use an electrolytic capacitor.

The driving control unit 40 allows the respective groups 31, 32, 33, and 34 of the light emitting unit 30 to emit light in the phase state including the peak portion of the pulsating voltage, .

Also, the capacitor C1 may be charged while the first group 31 to the third group 33 of the light emitting portion 30 emit light, even when the pulsating voltage is lower than the peak portion.

At this time, the charging voltage of the capacitor C1 may be set to be larger than the operating voltage of the first group 31. [ That is, the first group 31 and the second group 32 of the light emitting unit 30 are connected in parallel to the capacitor C1, so that the first group 31 and the second group 32 are connected to the capacitor C1. Can be charged at the same time.

As described above, the charging and discharging voltage or the charge amount of the capacitor C1 can be controlled to be constantly lower than the maximum capacity of the capacitor C1, so that the life of the capacitor C1 may not be limited.

That is, the capacitors, such as the smoothing capacitor, in which the maximum charge and discharge voltage allowed by the capacitor are periodically charged and discharged may be shortened in life. However, the capacitor used in the embodiment shown in FIG. Value can be controlled in a range much lower than the maximum charge and discharge voltage allowed by the capacitor, so that the lifetime of the capacitor can be greatly improved. In fact, the life of the drive circuit shown in Fig. 1 is not significantly limited by the lifetime of the capacitor.

The drive control unit 40 selectively connects at least one group among the first group 31, the second group 32, the third group 33, and the fourth group 34 of the light emitting unit 30 And at least one switch (SW1, SW2) for controlling the flow of the current so as to be driven.

1 shows a state in which two switches SW1 and SW2 for controlling the flow of electric current to four groups 31, 32, 33 and 34 of the light emitting portion 30 are formed.

That is, these switches have a first switch SW1, a first group 31, a second group 32, and a third group (third group) 31 for allowing a current to flow through the first group 31 and the capacitor C1 And a second switch SW2 for allowing a current to flow through the second switch SW2.

At this time, when both the switches are opened, a current can flow through all four groups 31, 32, 33, and 34 of the light emitting unit 30. In this case, the capacitor C1 can be charged together have.

Further, control circuits 41 and 42 for controlling the switches SW1 and SW2, respectively, can be configured. The constant current circuit 43 may further be included in the first and second control circuits 41 and 42, the first and second switches SW1 and SW2, and the fourth group 34. [

The constant current circuit 43 is separately connected to the first and second switches SW1 and SW2 and the fourth group 34 to improve the power factor.

The first switch SW1 is connected between the first group 31 and the second group 32 so that when the discharge of the capacitor C1 occurs, the first switch SW1 is connected to the capacitor C1 and the first group 31 So that the light emitting diodes belonging to the first group 31 can be turned on.

As described above, in the LED driving apparatus directly driven by the AC power source, it is possible to continuously drive without the discontinuous section of the light emitting diode light, and the flicker phenomenon can be improved.

This continuous driving is possible by having the capacitor C1 and charging the capacitor C1 higher than the driving voltage of the first group 31 of the light emitting portion 30. [

At this time, the charging and discharging voltage or the charge amount of the capacitor C1 can be controlled to be constantly lower than the maximum capacity of the capacitor C1, so that the life of the capacitor C1 may not be limited.

Hereinafter, the operation of the circuit of FIG. 1 will be described in detail as time progresses.

First, the circuit will be described on the assumption that the capacitor C1 is charged to such a degree as to drive the first group 31 by the initial drive. Since the capacitor C1 is connected in parallel to the first group 31 and the second group 32, the capacitor C1 can be charged to a value greater than the driving voltage of the first group 31. [

2A and 2B, when the first switch SW1 is turned on by the operation of the first control circuit 41, the current flows through D1 So that the current charged in the capacitor C1 drives the first group 31 (Group 1).

Therefore, when the magnitude of the pulsating voltage V1 is lower than the drive voltage for emitting light in any one of the groups belonging to the light emitting portion 30, the first group 31 emits light by the charge of the capacitor C1 State.

3A and 3B, when the first switch SW1 is turned on by the operation of the first control circuit 41, the pulse-like voltage V1 is turned on, The first group 31 emits light.

When the magnitude of the pulsating voltage V1 becomes larger, the second control circuit 42 operates to turn on the first group 31 while the second switch SW2 is turned on, as shown in FIGS. 4A and 4B. , The second group (32), and the third group (33) are turned on.

At this time, a current can also flow to the side of the capacitor C1 connected in parallel to the first group 31 and the second group 32, and the capacitor C1 can be charged by the current.

5A and 5B, the switches SW1 and SW2 are turned off and the first group 31 and the second group 31 are turned off in the phase state including the peak portion, The group 32, the third group 33, and the fourth group 34 are all in a light emitting state.

At this time, the current flows through the path directly connected to the fourth group 34 and the constant current circuit 43. Current also flows to the side of the capacitor C1 connected in parallel with the first group 31 and the second group 32, and the capacitor C1 is charged by this current.

6A and 6B, the first group 31 and the second group 31 are turned on by the pulsating voltage V1 while the second switch SW2 is turned on, 32 and the third group 33 emit light.

A current can flow also to the side of the capacitor C1 connected in parallel to the first group 31 and the second group 32 as in the state shown in Figs. 4A and 4B. By this current, the capacitor C1 is charged .

Thereafter, when the pulsating voltage V1 becomes smaller, the first group 31 emits light by the pulsating voltage V1 in a state in which the first switch SW1 is turned on as shown in Figs. 7A and 7B .

Thereafter, when the magnitude of the pulsating voltage V1 becomes lower than the driving voltage of the first group 31, the current is supplied from the capacitor C1 and the first group 31 is supplied with the discharge current of the capacitor C1 Emitting state.

Therefore, even if the magnitude of the pulsating voltage V1 is smaller than the voltage capable of emitting light from the light emitting portion 30, at least the light emitting diodes belonging to the first group 31 can be turned on, so that the discontinuous section of the light disappears, It can be driven.

In addition, the voltage charged in the capacitor C1 can be optimized to minimize the drive loss according to the input voltage.

9 shows another example of the LED driving apparatus. This driving apparatus includes a rectifying section 20 which rectifies the AC power source 10 to output a pulsating voltage, and is driven by the pulsating voltage and includes a plurality of LEDs connected in series, and at least three groups 31, 32, and 33, respectively.

At least two groups of the group of the light emitting units 30 are connected in parallel with the capacitor C1. The capacitor C1 may be connected to a zener diode Dz to constitute a current flow.

Fig. 9 shows a light emitting portion 30 including three groups. That is, the first group 31 (Group 1), the second group 32 (Group 2), and the third group 33 (Group 3) are shown.

The driving control unit 40 may selectively drive at least one group of the groups of the light emitting units 30 according to the magnitude of the pulsating current passing through the rectifying unit 20. [

When the pulse voltage is lower than the operating voltage of the light emitting unit 30, the driving control unit 40 controls the light emitting unit 30 using the discharging current of the capacitor C1 connected to at least one group of the light emitting unit 30. [ 30 can be controlled to be driven.

At this time, resistors R4 and R5 may be connected between the first group 31 and the second group 32 and between the capacitor C1 and the Zener diode Dz, respectively.

9, among the first group 31 and the second group 32 connected in parallel with the capacitor C1, when the pulsating voltage is lower than the operating voltage of the light emitting part 30, The light emitting diodes belonging to the group 31 can be driven. That is, the first group 31 of the light emitting portions 30 may be included in the discharge path of the capacitor C1.

Therefore, in driving the light emitting portion 30 including the plurality of groups 31, 32, 33, and 34, even when the pulsating voltage is lower than the operating voltage of any one group of the light emitting portions 30 The light emitting unit 30 can be continuously driven without a discontinuous section of light by the light emitting unit 30. In this case,

A first switch SW1 is connected between the first group 31 and the resistor R4 and a second switch SW1 is connected to the third group 33. [ Further, control circuits 41 and 42 for controlling the switches SW1 and SW2, respectively, can be configured.

The driving control unit 40 may further include a dimming control unit 44 that can adjust the brightness of the light emitting unit 30. [

The zener diode Dz which forms the discharge path of the capacitor C1 can act as a circuit protecting portion to prevent an overcurrent from flowing in the circuit. In some cases, a TVS (Transient Voltage Suppressor) chip may be used instead of the Zener diode Dz.

The Zener diode (Dz) or TVS chip can clamp the overvoltage or overcurrent so that it does not reach the light emitting portion (30) side when an overvoltage is applied to the circuit.

In the circuit shown in FIG. 9, a current loop in which two groups 31 and 32 connected in parallel with the capacitor C1 emit light may be formed according to the magnitude of the pulsating voltage.

In the state of Fig. 9, the charging voltage of the capacitor C1 may be set to be larger than the operating voltage of the first group 31. [ That is, since the first group 31 and the second group 32 of the capacitor C1 and the light emitting unit 30 are connected in parallel with the resistors R4 and R5 connected to each other, A voltage higher than the driving voltage of the capacitor 31 can be charged.

As described above, the charging and discharging voltage or the charge amount of the capacitor C1 can be controlled to be constantly lower than the maximum capacity of the capacitor C1, so that the life of the capacitor C1 may not be limited. Unless explained, the same things as described in the example of Fig. 1 can be applied.

Hereinafter, the operation of the circuit of FIG. 9 will be described in detail as time progresses.

First, the circuit will be described on the assumption that the capacitor C1 is charged to such a degree as to drive the first group 31 by the initial drive. Since the capacitor C1 is connected in parallel to the first group 31 and the second group 32, the capacitor C1 can be charged to a value greater than the driving voltage of the first group 31. [

10A and 10B, when the first switch SW1 is turned on by the operation of the first control circuit 41, the current flows in the Zener diode The current charged in the capacitor C1 through the first and second groups Dz and Dz drives the first group 31 (Group 1) and the second group 32 (Group 2).

As such, the current driving the second group 32 can be looped through the resistor R5 and the capacitor C1. In addition, the path of the current flows through the first group 31 of the discharge current of the capacitor C1 and can be made toward the first switch SW1, the resistor R1 and the diode D2.

Therefore, when the magnitude of the pulsating voltage V1 is lower than the driving voltage for emitting light in any one of the groups belonging to the light emitting portion 30, the charges of the first group 31 and the second The group 32 is in a state of emitting light.

At this time, for example, the first group 31 and the second group 32 may be driven with a voltage value of 135 V and 5 V, respectively.

11A and 11B, when the first switch SW1 is turned on by the operation of the first control circuit 41, the pulse-like voltage V1 is turned on, The first group 31 and the second group 32 emit light.

At this time, a current loop may be formed in the path through which the first group 31, the second group 32 and the capacitor C1 are connected, and the first switch SW1, the resistor R1 and the diode D2 .

Thereafter, in the phase state including the peak portion due to the increase in the pulsating voltage V1, the first group 31 and the second group 32 are turned on with the second switch SW2 turned on as shown in Figs. 12A and 12B And the third group 33 emit light.

At this time, the current flows to the resistor R2 side through the first group 31, the second group 32 and the third group 33 and the second switch SW2. The current also flows to the side of the capacitor C1, and the capacitor C1 is charged by this current.

At this time, for example, the first group 31 may be driven with a voltage value of 135V, the second group 32 may be driven with a voltage of 5V, and the third group 33 may be driven with a voltage value of 115V.

Next, when the pulsating current voltage V1 decreases again, the first group 31 and the second group 31 are turned on by the pulsating voltage V1 in the state in which the first switch SW2 is turned on as shown in Figs. 13A and 13B 32) emit light.

In this case, as in the states shown in Figs. 11A and 11B, a current loop can be formed in the path where the first group 31, the second group 32, and the capacitor C1 are connected, The switch SW1, the resistor R1 and the diode D2.

14A and 14B, when the first switch SW1 is turned on, the current flows through the Zener diode Dz to the capacitor C1, The first group 31 (Group 1) and the second group 32 (Group 2) are driven.

As such, the current driving the second group 32 can be looped through the resistor R5 and the capacitor C1. In addition, the path of the current flows through the first group 31 of the discharge current of the capacitor C1 and can be made toward the first switch SW1, the resistor R1 and the diode D2. These matters may be the same as those in Figs. 10A and 10B.

Therefore, when the magnitude of the pulsating voltage V1 is lower than the driving voltage for emitting light in any one of the groups belonging to the light emitting portion 30, the charges of the first group 31 and the second The group 32 is in a state of emitting light.

In some cases, only the light emitting diodes belonging to the first group 31 may emit light without a current loop. This can also be applied to the case of Figs. 10A and 10B.

As described above, even when the magnitude of the pulsating voltage V1 is smaller than the voltage capable of emitting light from the light emitting portion 30, at least the light emitting diodes belonging to the first group 31 can be turned on so that the discontinuous portion of the light disappears, .

The light emitting diode driving apparatus described above can be continuously driven without discontinuous sections of light emitting diodes in an LED driving apparatus that is directly driven by the AC power source 10 to improve the flickering phenomenon.

This continuous driving includes the capacitor C1 and a constant output can be controlled by adjusting the control voltage of the dimming control unit 44 according to the input voltage.

At this time, the charging and discharging voltage or the charge amount of the capacitor C1 can be controlled to be constantly lower than the maximum capacity of the capacitor C1, so that the life of the capacitor C1 may not be limited.

Furthermore, since the dimming control section 44 is implemented at the common reference potential, the circuit configuration can be simply configured.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

10: AC power supply 20:
30: light emitting portion 31: first group
32: second group 33: third group
34: fourth group 40: drive control unit
41: first control circuit 42: second control circuit
43: constant current circuit 44: dimming control section

Claims (15)

A rectifying unit for rectifying the AC power supply to supply a pulsating voltage;
A light emitting unit connected to the rectifying unit and including a plurality of light emitting diodes connected in series, the light emitting unit including two or more groups;
A capacitor connected in parallel with at least two groups of the light emitting units; And
And at least one group of the light emitting units is selectively driven according to the magnitude of the pulsating voltage, and when the pulsating voltage is lower than the operating voltage of the light emitting unit, a discharge of the capacitor connected to at least one group of the light emitting units And a drive control unit for driving at least one group of the group of light emitting units connected in parallel with the capacitor using a current,
The light emitting unit includes a first group and a second group connected in parallel with the capacitor and a third group connected to the second group, and the charging voltage of the capacitor is greater than the operating voltage of the first group Wherein the light emitting diode driving device comprises: The light emitting diode driving apparatus according to claim 1, wherein the drive control unit controls to charge the capacitor in a phase state including a peak portion of the ripple voltage. delete The light emitting diode driving apparatus according to claim 1, wherein the light emitting unit further comprises a fourth group connected to the third group. The light emitting diode driving apparatus according to claim 1, wherein the drive control unit drives the light emitting diodes belonging to the first group by a discharge current of the capacitor. 2. The light emitting diode drive device according to claim 1, wherein the drive control unit controls the first group, the second group, and the third group to emit light in a phase state including a peak portion of the ripple voltage. . delete The drive control apparatus according to claim 1,
At least one switch for controlling a current flow to selectively drive at least one of the first group, the second group, and the third group; And
And a control circuit for controlling the switch. 9. The apparatus of claim 8, wherein the switch comprises: a first switch for allowing current to flow through the capacitor and the first group; And
And a second switch for allowing current to flow through the first group, the second group, and the third group. 2. The LED driving apparatus according to claim 1, further comprising a dimming control unit for adjusting a brightness of the light emitting unit. The light emitting diode driving apparatus according to claim 1, wherein a circuit protection unit is connected to the capacitor. 12. The LED drive device according to claim 11, wherein the circuit protection part includes a Zener diode or a TVS chip. 2. The LED driving apparatus according to claim 1, wherein a current loop in which two groups connected in parallel with the capacitor are emitted is formed according to the magnitude of the ripple voltage. The light emitting diode driving apparatus according to claim 1, wherein the drive control unit controls the charge voltage of the capacitor within a voltage range lower than a maximum charge voltage of the capacitor. The light emitting diode driving apparatus according to claim 1, wherein the driving control unit further comprises a constant current circuit connected to the light emitting unit.

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