KR20150026349A - Apparatus for lighting using light emitting diode - Google Patents

Abstract

The present invention relates to a lighting device, and more particularly, to a lighting apparatus using light emitting diodes which emits two or more colors. According to the present invention, the lighting apparatus comprises; a power circuit which supplies a voltage by rectifying an AC voltage; an emission unit including a first light emitting diode which emits light having a first wavelength band and a second light emitting diode which emits light having a second wavelength band; a first switch element; a driving circuit which is connected to the power circuit to drive the emission unit; and a control circuit which alternatively connects the second light emitting diode to the driving circuit to drive the second light emitting diode and controls an emitted color according to a driving ratio of the first light emitting diode and the second light emitting diode.

Description

[0001] The present invention relates to a light emitting diode (LED)

The present invention relates to a lighting apparatus, and more particularly, to a lighting apparatus using a light emitting diode that emits two or more colors.

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 utilize such a light emitting diode as a light source of an illumination, a light emitting diode driving device capable of being driven by a commercial AC power source is needed.

In small-power lighting using light emitting diodes, a driver circuit of small size, high efficiency, and high power factor is required.

2. Description of the Related Art [0002] Generally, as an LED that emits light of a bulb color, one type of LED including a blue light emitting LED and a phosphor emitting yellow color is used. Recently, however, there is a demand for high color rendering and high efficiency.

Accordingly, LEDs emitting light of different colors can be added to the illumination circuit, and therefore, a circuit capable of effectively controlling these different kinds of LEDs is required.

An object of the present invention is to provide a light emitting diode lighting apparatus capable of effectively controlling two or more types of light emitting diodes that emit light of two or more colors in a light emitting diode lighting apparatus.

According to a first aspect of the present invention, there is provided a power supply circuit comprising: a power supply circuit for rectifying an AC power supply to supply power; A light emitting unit including a first light emitting diode for emitting light of a first wavelength band and a second light emitting diode for emitting light of a second wavelength band; A driving circuit including a first switching element and connected to the power supply circuit to drive the light emitting unit; And a control circuit for selectively driving the second light emitting diode to drive the first light emitting diode and controlling the emission color according to a driving ratio of the first light emitting diode and the second light emitting diode.

Here, the current peak value can be driven to be the same regardless of the drive ratio by the control circuit.

Here, the first light emitting diode may be a white light emitting diode and the second light emitting diode may be a red light emitting diode.

Here, the control circuit may include: a second switch element connected between the first light emitting diode and the second light emitting diode; A first detection resistor connected to the second switch element; A second detection resistor connected to the second light emitting diode; And a PWM generator for controlling the second switch element.

In this case, the light emitting device may further include a temperature sensor positioned on the light emitting unit side.

The PWM generator may operate based on the detection values of the first detection resistor and the second detection resistor and the temperature information of the temperature sensor.

On the other hand, the drive circuit can use a step-down converter circuit.

The step-down converter circuit includes: a regenerative diode connected to the power supply circuit; An inductor connected between the regenerative diode and the light emitting unit to generate a regenerative current; The first switch element controlling the regenerative current generated by the inductor to be supplied to the light emitting portion; And a controller for controlling the first switch element.

Here, by the control circuit, the light emitting unit can be driven by a first pattern in which the first light emitting diode is driven, and a second pattern in which the first light emitting diode and the second light emitting diode are simultaneously driven.

At this time, the current peak value when driven by the first pattern and the second pattern may be the same.

On the other hand, the power supply circuit includes: a rectifying circuit for rectifying an AC voltage input from an AC power supply; A PFC circuit operating by an output voltage of the rectifying circuit; And an input filter positioned between the rectifying circuit and the PFC circuit.

According to a second aspect of the present invention, there is provided a rectifying circuit for rectifying an AC voltage input from an AC power supply; A PFC circuit operating by an output voltage of the rectifying circuit; A light emitting unit including a first light emitting diode for emitting light of a first wavelength band and a second light emitting diode for emitting light of a second wavelength band; A driving circuit connected to the PFC circuit to drive the light emitting unit; And a control circuit for selectively driving the second light emitting diode to drive the first light emitting diode and controlling the emission color according to a driving ratio of the first light emitting diode and the second light emitting diode.

Here, by the control circuit, the light emitting portion is driven by a first pattern in which the first light emitting diode is driven and a second pattern in which the first light emitting diode and the second light emitting diode are simultaneously driven, The current peak value when driven by the first pattern and the second pattern may be the same.

The present invention has the following effects.

First, the light emission color of the illumination can be controlled according to the driving ratio of the first light emitting diode and the second light emitting diode.

According to the control circuit of the present invention, the light emitting portion can be driven by the first pattern in which the first light emitting diode is driven and the second pattern in which the first light emitting diode and the second light emitting diode are simultaneously driven.

At this time, the current peak values when driven by the first pattern and the second pattern can be driven to be the same. Therefore, there is an effect that a circuit can be constituted by using a general-purpose constant current power source IC.

1 shows an example of a light emitting diode illumination device.
2 is a waveform diagram showing an operation waveform of the lighting apparatus shown in Fig.
3 shows another example of the light emitting diode illumination device.
Fig. 4 is a waveform diagram showing an operation waveform of the illumination device shown in Fig. 3. Fig.

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.

1 shows an example of a light emitting diode illumination device.

As shown in Fig. 1, the light emitting diode (LED) lighting apparatus is supplied with power through a power supply circuit 10a that rectifies the AC power supply 10 to supply power.

The power supply circuit 10a includes a rectifying circuit 20 for rectifying an AC voltage input from the AC power supply 10 and a PFC circuit (Boost PFC) 30 operated by the output voltage of the rectifying circuit 20 can do. This PFC circuit 30 can control the power factor of the circuit.

This rectifier circuit 20 can use a full-wave rectifier circuit using a bridge diode.

At this time, it may include an input filter 31 located between the rectifying circuit 20 and the PFC circuit 30. The input filter 31 may include a PIE type structure including an inductor L1 connecting the two capacitors C1 and C2.

And a light emitting unit 80 driven by a power source supplied from the power supply circuit 10a. The light emitting unit 80 includes a first light emitting diode 40 that emits light in a first wavelength band, And a second light emitting diode (50) for emitting light of a band.

In this case, the first light emitting diode 40 may be a main light emitting diode for illumination, and may include a plurality of light emitting diodes D _W connected in series or in parallel.

The second light emitting diode 40 is a light emitting diode capable of adjusting the quality of the light, for example, the color, the color tone, the color rendering, and the color temperature of the light, and also includes a plurality of light emitting diodes D _R ). However, the second light emitting diode 40 may be a single light emitting diode (D _R ) as the case may be.

For example, the first light emitting diode 40 may be a light emitting diode that emits white light, and the second light emitting diode 50 may be a light emitting diode that emits red light. However, it is not limited thereto.

The light emitting unit 80 includes a driving circuit 60b for driving the light emitting unit 80 using the power received from the power supply circuit 10a.

This driving circuit 60b can use a BUCK converter circuit having excellent efficiency.

The driving circuit 60b composed of such a step-down converter circuit includes a regenerative diode D1 connected to the power supply circuit 10a and a regenerative diode D1 connected between the regenerative diode D1 and the light emitting portion 80, An inductor L2 and a first switch element Q1 for controlling the regenerative current generated by the inductor L2 to be supplied to the light emitting portion 80 and a control portion 70 for controlling the first switch element Q1, . ≪ / RTI >

At this time, a detection resistor R3 capable of detecting the entire current may be connected to the first switch element Q1.

In this case, the control unit 70 includes a gate voltage generating unit 71 for controlling the first switch element Q1 and a current detecting unit 72 capable of detecting a current through the detecting resistor R3 can do.

The control circuit 60a is configured to selectively drive the second light emitting diode 50 among the light emitting units 80 to be connected to the drive circuit 60b.

The control circuit 60a can control the emission color of the light according to the driving ratios of the first light emitting diode 40 and the second light emitting diode 50. [

The control circuit 60a includes a second switch element Q2 connected between the first light emitting diode 40 and the second light emitting diode 50 and a PWM generator 60 for controlling the second switch element Q2. (60).

The light emitting diode further includes a first detection resistor R1 connected to the second switch element Q2 and a second detection resistor R2 connected to the second light emitting diode 50. [

At this time, the PWM generator 60 may further include a temperature sensor NTC located at the light emitting unit 80 side.

Accordingly, the PWM generator 60 can operate by the voltage detection value through the first detection resistor R1 and the second detection resistor R2 and the temperature information of the temperature sensor NTC.

The control circuit 60a controls the light emitting unit 80 to drive the first pattern in which the first light emitting diode 40 is driven and the first pattern in which the first light emitting diode 40 and the second light emitting diode 50 are driven simultaneously And can be driven by the second pattern.

At this time, the current peak values when driven by the first pattern and the second pattern can be driven to be the same. Therefore, the control circuit 60a or the drive circuit 60b can be constituted by using a general-purpose constant current power source IC.

As described above, the illumination color can be adjusted by the ratio of the number of the first pattern to the number of the second pattern.

Hereinafter, the first light emitting diode 40 is a white light emitting diode (D _W ) that emits white light, and the second light emitting diode 50 is a red light emitting diode (D _R ) that emits red light.

2 is a waveform diagram showing an operation waveform of the lighting apparatus shown in Fig. Here, the first pattern is represented by a pattern A and the second pattern is represented by a pattern B.

2 (a) shows the operation waveform (voltage) of the PWM control section 60 of the control circuit 60a, (b) shows the gate voltage of the first switch element Q1 of the drive circuit 60b have.

2 (c) shows the gate voltage of the second switch element Q2 of the control circuit 60a. Therefore, as shown in the figure, since the second switch element Q2 is not operated in the pattern A, current is supplied to the red light emitting diode D _R.

In the pattern B, since the second switch element Q2 operates (13), no current is supplied to the red light emitting diode D _R.

As described above, the pattern A and the pattern B are combined to drive the light emitting portion 80, so that illumination can be performed in a desired color.

For example, when it is desired to lower the color temperature (i.e., increase the lighting current of the red light emitting diode D _R ), the pattern A can be increased and the pattern B can be reduced.

That is, in FIG. 2, it operates in the same state as that of AAABB during one cycle of the pulsating voltage. By changing from AAABB to AAAAB, the color temperature can be lowered.

Conversely, when it is desired to raise the color temperature (that is, when the lighting current of the red light emitting diode D _R is reduced), the pattern A is decreased and the pattern B is increased.

That is, the color temperature can be increased by changing from the driving pattern AAABB in FIG. 2 to AABBB.

The detailed operation of the pattern A will be described below.

2 (b), when the gate voltage of the first switch element Q1 of the drive circuit 60b is applied and the first switch element Q1 is turned on, as shown in (d) , The amount of current flowing in the inductor L2 increases. That is, (d) shows the amount of current flowing in the inductor L2.

At this time, when the current flowing through the inductor L2 reaches the set current amount, the first switch element Q1 is turned off.

As described above, when the first switch element Q1 is turned off, the amount of current flowing in the inductor L2 decreases as shown in (d).

Accordingly, when the amount of current flowing through the inductor L2 becomes zero, the first switch element Q1 is turned on again as shown in (b).

This operation may be referred to as a so-called critical current mode (CCM) operation.

In Pattern A, as shown in (c), because the second switch element (Q2) is turned off (off), current flows through the both sides of the white LED _(W D) and the red light-emitting diode (D _R). More detailed operation will be described as follows.

That is, as shown in (e), the current flowing only through the white light emitting diode (D _W ) is zero.

Further, as shown in (f), the current flowing through both the white light emitting diode D _W and the red light emitting diode D _R is equal to the inductor L2 current shown in (d).

The total operating voltage Vf of the white light emitting diode D _W and the red light emitting diode D _R is 40 V by adding 15 V and 25 V as shown in (h).

Next, the detailed operation of the pattern B will be described. The operation of the driving circuit 60b of the pattern B is basically the same as that of the pattern A, and only the difference will be described below.

In the pattern B, so that the second switch element (Q2) of the control circuit (60a) is turned on (on), the white LED electric current flows only (D _W). A more detailed operation will be described below.

That is, the current flowing only to the white light emitting diode (D _W ) shown in (e) is the same as the inductor (L2) current shown in (d).

As shown in (f), a white light emitting diode _(W D) and the red light-emitting diode (D _R) the current flowing through the both is zero.

The total operating voltage Vf of the light emitting unit 80 is 25V.

3 shows another example of the light emitting diode illumination device.

The circuit of the lighting apparatus shown in Fig. 3 is basically the same as the circuit diagram of Fig. However, the NOR circuit 61 for generating the gate signal of the second switch element Q2 of the control circuit 60a is different from the first embodiment.

Fig. 4 is a waveform diagram showing an operation waveform of the illumination device shown in Fig. 3. Fig. Here, the first pattern is represented by a pattern A and the second pattern is represented by a pattern B.

In this embodiment, the pattern B shown in Fig. 4 corresponds to the total driving voltage Vf of the light emitting portion 80 during the period when the first switching element Q1 of the driving circuit 60b is on, The driving voltage can be set to 40 V, which is one of the objects of the present embodiment.

Thus, the following effects can be obtained.

4 (g) shows the detection current through the current detection unit 72 of the control unit 70. In FIG.

As described above, the control unit 70 can use an IC for a BUCK converter. The current detecting unit 72 detects only the current during a period when the first switching device Q1 is on.

The IC constituting the current detecting section 72 operates on the premise that the IC does not detect the driving voltage Vf of the light emitting section 80 but is a constant voltage.

1, the voltage (40V) of the light emitting portion 80 in the state in which the first switch element Q1 of the pattern A is on and the voltage (40V) of the first switch element Q1 in the pattern B are the same as in the case of the example shown in Fig. The voltage of the light emitting portion 80 in the on state is different from 25 V, which may cause an error in the power control.

3, the voltage (40V) of the light emitting portion 80 in the state that the first switch element Q1 of the pattern A is on and the first switch element Q1 of the pattern B The voltage of the light emitting portion 80 in the ON state is equal to 40 V, so that the error of the power control can be reduced.

In this example of the circuit of Fig. 1, the point of change when changing to the circuit of Fig. 3 is the signal of the second switch element Q2 of the pattern B (Fig. 4 (c)).

In the example of Fig. 1, the signal (Fig. 2 (c)) of the second switch element Q2 of the pattern B is in the high state (5 V).

On the other hand, in the example of Fig. 3, the signal (Fig. 4 (c)) of the second switch element Q2 of the pattern B is generated only in the section where the signal of the first switch element Q1 is low 2 The signal of the switching element Q2 is in a high state.

The signal of the second switching element Q2 is generated by the NOR circuit 61 and the signal of the PWM control unit 60 (FIG. 4 (a)) for controlling the color.

By changing the signal of the second switch element Q2, it is possible to change from the circuit of Fig. 1 to the circuit of Fig.

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 10a: Power supply circuit
20: rectifying circuit 30: PFC circuit
31: input filter 40: first light emitting diode
50: second light emitting diode 60: PWM control section
60a: control circuit 60b: driving circuit
61: NOR circuit 70:
71: gate voltage generator 72: current detector
80:

Claims (13)

A power supply circuit for rectifying AC power to supply power;
A light emitting unit including a first light emitting diode for emitting light of a first wavelength band and a second light emitting diode for emitting light of a second wavelength band;
A driving circuit including a first switching element and connected to the power supply circuit to drive the light emitting unit; And
And a control circuit for selectively driving the second light emitting diode to drive the first light emitting diode and controlling the emission color according to the driving ratio of the first light emitting diode and the second light emitting diode. Lighting device. The light emitting diode illumination device according to claim 1, wherein the current peak value is driven to be the same regardless of the drive ratio by the control circuit. The LED lighting apparatus of claim 1, wherein the first light emitting diode is a white light emitting diode and the second light emitting diode is a red light emitting diode. 2. The control circuit according to claim 1,
A second switch element connected between the first light emitting diode and the second light emitting diode;
A first detection resistor connected to the second switch element;
A second detection resistor connected to the second light emitting diode; And
And a PWM generator for controlling the second switch element. The light emitting diode lighting apparatus according to claim 4, further comprising a temperature sensor located on the light emitting unit side. The light emitting diode illuminating apparatus according to claim 5, wherein the PWM generator operates based on the detected values of the first detecting resistor and the second detecting resistor and the temperature information of the temperature sensor. The light emitting diode illumination device according to claim 1, wherein the drive circuit is a step-down converter circuit. 8. The power converter according to claim 7, wherein the step-
A regenerative diode connected to the power supply circuit;
An inductor connected between the regenerative diode and the light emitting unit to generate a regenerative current;
The first switch element controlling the regenerative current generated by the inductor to be supplied to the light emitting portion; And
And a control unit for controlling the first switch element. 2. The light emitting device according to claim 1, wherein the control circuit controls the light emitting unit to be driven by a first pattern in which the first light emitting diode is driven and a second pattern in which the first light emitting diode and the second light emitting diode are simultaneously driven And a light emitting diode (LED). 10. The light emitting diode lighting apparatus according to claim 9, wherein a current peak value when driven by the first pattern and the second pattern is the same. The power supply circuit according to claim 1,
A rectifying circuit for rectifying an AC voltage input from an AC power source;
A PFC circuit operating by an output voltage of the rectifying circuit; And
And an input filter disposed between the rectifying circuit and the PFC circuit. A rectifying circuit for rectifying an AC voltage input from an AC power source;
A PFC circuit operating by an output voltage of the rectifying circuit;
A light emitting unit including a first light emitting diode for emitting light of a first wavelength band and a second light emitting diode for emitting light of a second wavelength band;
A driving circuit connected to the PFC circuit to drive the light emitting unit; And
And a control circuit for selectively driving the second light emitting diode to drive the first light emitting diode and controlling the emission color according to the driving ratio of the first light emitting diode and the second light emitting diode. Lighting device. The driving circuit according to claim 12, wherein, by the control circuit, the light emitting portion is driven by a first pattern in which the first light emitting diode is driven and a second pattern in which the first light emitting diode and the second light emitting diode are simultaneously driven And the current peak value when driven by the first pattern and the second pattern is the same.

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