KR101171752B1 - LED Lighting System for improving reliability - Google Patents

Abstract

An LED lighting apparatus is disclosed in which reliability is improved. LED lighting device of the present invention is a rectification generation block for generating a rectified voltage, the rectified voltage is a rectification generation block having a driving voltage difference in one direction with respect to a predetermined ground voltage; An LED light emitting block comprising first and second connectors, a first LED module, and a second LED module, wherein the first LED module is formed between the rectified voltage and the first connection node. The first connection node is formed between the first connection node and the second connection node, and the first connection unit electrically connects the first connection node to the ground voltage in response to a first control signal, wherein the first LED module and the first connection node are electrically connected to each other. 2 LED module is driven to regulate the current of the LED module, the second connector is the LED light emitting block is driven to electrically connect the second connection node to the ground voltage in response to a second control signal; And a control block for generating the first control signal and the second control signal controlled in a state corresponding to the magnitude of the driving voltage difference. According to the LED lighting apparatus of the present invention, while the complexity of the circuit structure and the operation characteristics such as power efficiency, power factor, etc. can be easily improved without using a capacitor, an inductor, and a PFC IC, the transient current of the LED module included in the closed loop current loop is reduced. do. In addition, when a low voltage level is applied to the gate terminal of the NMOS transistor, the possibility of breakage of the NMOS transistor is significantly reduced, and the overall reliability is greatly improved.

Description

LED Lighting System for Improved Reliability {LED Lighting System for improving reliability}

The present invention relates to an LED (LED) lighting device, and more particularly to an LED lighting device for improving reliability along with operating characteristics such as efficiency and power factor.

A light emitting diode (LED) device is a kind of compound semiconductor and emits light by an applied voltage. Such LED devices have the advantages of small size, long life, and high efficiency of converting electrical energy into light energy. Accordingly, the LED lighting device using the LED element is gradually developed as a lighting device to replace the incandescent lamp and the fluorescent lamp.

The conventional LED lighting apparatus is comprised from the AC supply 10, the bridge diode 20, and the LED light emission block 30, as shown in FIG. The bridge diode 20 rectifies the AC voltage VAC supplied from the AC supply 10 to generate the rectified voltage VREC. The LED elements of the LED light emitting block 30 emit light by the rectified voltage VREC.

However, in the conventional LED lighting apparatus, when the rectified voltage VREC is lower than or equal to a predetermined voltage, the luminance of all the LED elements becomes very low, and in some cases, all the LED elements are turned off. Therefore, the conventional LED lighting device has a problem of low power efficiency.

In order to solve this problem, an LED lighting apparatus as shown in FIG. 2 has been proposed. LED lighting device of Figure 2 is a light emitting LED number control type. In the light emitting LED number control type LED lighting device of FIG. (SW1, SW2) are controlled. According to whether the first and second NMOS transistors SW1 and SW2 are turned on, one or both of the first and second LED modules MD1 and MD2 emit light. According to the LED lighting device of Figure 2, it is possible to simply improve and increase the power efficiency, power factor without the complexity of the circuit structure and the use of capacitors, inductors, PFC ICs.

However, in the LED illuminating device of FIG. 2, the source terminal of the first NMOS transistor is connected to the connection node NC. At this time, considering that the voltage difference between the positive supply voltage VSUP + and the negative supply voltage VSUP- is 50V to 100V, the voltage of the source terminal of the first NMOS transistor SW1 connected to the connection node NC. The level is 25V to 50V. Therefore, the first control signal VC1 gating the first NMOS transistor SW1 requires a voltage level higher than 25V to 50V.

As such, since a high level of voltage is applied to the gate terminal, the first NMOS transistor SW1 has a high possibility of damage.

In addition, in the LED lighting apparatus of FIG. 2, when transient currents are generated instantaneously, device characteristics of the LED modules MD1 and MD2 may be rapidly degraded.

Therefore, the LED lighting apparatus of FIG. 2 has a problem that the reliability is greatly reduced.

An object of the present invention is to solve the problems of the prior art, to provide an LED lighting device that improves the reliability along with operating characteristics such as efficiency and power factor.

One aspect of the present invention for achieving the above technical problem relates to an LED lighting device. LED lighting device of the present invention is a rectification generation block for generating a rectified voltage, the rectified voltage is a rectification generation block having a driving voltage difference in one direction with respect to a predetermined ground voltage; A first LED module formed between the rectified voltage and a first connection node; A second LED module formed between the first connection node and the second connection node; A first connection part electrically connecting the first connection node to the ground voltage in response to a first control signal, the first connection part being driven to regulate current of the first LED module and the second LED module; A second connector driven to electrically connect the second connection node to the ground voltage in response to a second control signal; And a control block for generating the first control signal and the second control signal controlled in a state corresponding to the magnitude of the driving voltage difference. The first connection device may include a first switching device formed between the first connection node and a first feedback node, the first switching device having conductance controlled according to a voltage of a first comparison signal; A first comparison element generating the first comparison signal by comparing the voltage of the first feedback node with a predetermined reference voltage; And a first resistor element formed between the first feedback node and the ground voltage.

According to the LED lighting apparatus of the present invention, while the complexity of the circuit structure and the operation characteristics such as power efficiency, power factor, etc. can be easily improved without using a capacitor, an inductor, and a PFC IC, the transient current of the LED module included in the closed loop current loop is reduced. do. In addition, when a low voltage level is applied to the gate terminal of the NMOS transistor, the possibility of breakage of the NMOS transistor is significantly reduced, and the overall reliability is greatly improved.

A brief description of each drawing used in the present invention is provided.
1 and 2 is a view showing a conventional LED lighting device.
3 is a view showing an LED lighting apparatus according to an embodiment of the present invention.
4 is a view illustrating a rectified voltage generated by rectifying an AC voltage in the LED lighting apparatus of FIG. 3.

For a better understanding of the present invention and its operational advantages, and the objects attained by the practice of the present invention, reference should be made to the accompanying drawings, which illustrate preferred embodiments of the invention, and the accompanying drawings. In understanding each of the figures, it should be noted that like parts are denoted by the same reference numerals whenever possible. In addition, in the following description, numerous specific details such as specific processing flows are described to provide a more general understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details. Incidentally, detailed descriptions of well-known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention are omitted.

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

3 is a view showing an LED lighting apparatus according to an embodiment of the present invention. Referring to FIG. 3, the LED lighting apparatus according to the embodiment of the present invention includes a rectification generation block 100, a first LED module MD1, a second LED module MD2, a first connection part 200, and a second The connection part 300 and the control block 400 are provided.

The rectification generation block 100 generates a rectified voltage VREC. In this case, the rectified voltage VREC has a driving voltage difference VLU in one direction with respect to the ground voltage VBAS. In this embodiment, the driving voltage difference VLU is changed over time.

Preferably, the rectification generation block 100 includes an AC supply 110 and a rectifier 120. The AC supply 110 supplies an AC voltage VAC. In this case, the AC supply 110 may be a self-generator that generates a current by itself, or may be a device for supplying a current received and supplied from the outside, such as home electricity.

The rectifier 120 rectifies the AC voltage VAC to provide the rectified voltage VREC. In this case, the ground voltage VBAS provided from the rectifier 120 is higher than the lowest voltage of the AC voltage VAC by the forward turn-on voltage of the diode used for rectification and is a reference voltage. The background voltage VBAS substantially corresponds to the ground voltage VSS.

Preferably, as illustrated in FIG. 3, the rectifier 120 rectifies the entire region of the AC voltage VAC to a voltage in the same direction to provide the rectified voltage VREC. It is a full-wave rectifier.

By the rectifier 120, a negative voltage at the alternating voltage VAC is rectified to a positive voltage of the rectified voltage VREC (see hatched in FIG. 3).

More preferably, the rectifier 120 is a bridge diode consisting of four diodes.

Referring to FIG. 3 again, the first LED module MD1 is formed between the rectified voltage VREC and the first connection node NC1, and the second LED module MD2 is connected to the first connection node (1). It is formed between NC1) and the 2nd connection node NC2. In this case, each of the first and second LED modules MD1 and MD2 includes one or more LED elements. The LED elements are connected in series or in parallel.

The first connector 200 is enabled in response to the first control signal VCON1 and is driven to connect the first connection node NC1 to the ground voltage VBAS. In addition, the second connector 300 is enabled in response to the second control signal VCON2, and is driven to connect the second connection node NC2 to the ground voltage VBAS.

The control block 400 detects the driving voltage difference VLU, that is, the voltage of the rectified voltage VREC with respect to the ground voltage VBAS, and controls the first and second control signals VCON1 and VCON2. Occurs. In this case, the first and second control signals VCON1 and VCON2 have a logic state corresponding to the driving voltage difference VLU.

Table 1 shows an example in which logic states of the first and second control signals VCON1 and VCON2 are determined according to the driving voltage difference VLU.

section I Ⅱ radiation
Voltage difference VLU ≤1 / 2 * Vp 1/2 * Vp < VLU VCON1 H L VCON2 L H

Here, Vp represents the peak voltage of the drive voltage difference VLU in the ideal case. At this time, the 1/2 * Vp may act as a threshold voltage in the present embodiment.

Referring to Table 1, the section I is a section in which the driving voltage difference VLU is 1/2 * Vp or less. In this section, the first control signal VCON1 is "H" and the second control signal VCON2 is "L". Therefore, the first connector 200 is enabled in response to the first control signal VCON1 and is driven to connect the first connection node NC1 to the ground voltage VBAS. In addition, since the second connection part 300 is disabled, the second connection node NC2 is electrically disconnected from the ground voltage VBAS.

Therefore, in the section I, the current path of the closed loop including the rectifier 120, the rectified voltage VREC, the first LED module MD1, the first connection part 200, and the ground voltage VBAS. Is formed, and the second LED module MD2 is excluded from the current path. In this case, only the LED elements of the first LED module MD1 emit light, and the LED elements of the second LED module MD2 are turned off.

The section II is a section in which the driving voltage difference VLU is larger than 1/2 * Vp. In this section, the first control signal VCON1 is "L" and the second control signal VCON2 is "H". Accordingly, the second connection part 300 is enabled in response to the second control signal VCON2 and is driven to connect the second connection node NC2 to the ground voltage VBAS. In addition, since the first connection unit 200 is disabled, the first connection node NC1 is electrically disconnected from the ground voltage VBAS.

Therefore, in the section II, the rectifier 120, the rectified voltage VREC, the first LED module MD1, the second LED module MD2, the second connection part 300, and the background voltage ( A closed loop current path consisting of VBAS) is formed. That is, a current path including both the first LED module MD1 and the second LED module MD2 is formed. In this case, the LED elements of both the first LED module MD1 and the second LED module MD2 emit light.

In this embodiment, the number of LED modules to be emitted is adjusted according to the driving voltage difference VLU. In other words, the number of light emitting LED elements is adjusted according to the magnitude of the rectified voltage VREC. Therefore, in the LED illuminating device of the present invention, the area where the LED element as a whole decreases in brightness or is turned off is significantly reduced.

Therefore, the LED illuminating device of the present invention has a significantly higher light emission amount than the LED illuminating device of FIG. In addition, the section in which the entire LED device is turned off is greatly reduced. Therefore, according to the LED lighting apparatus of the present invention, power factor and crest factor are remarkably improved.

Referring to FIG. 3 again, when the first connector 200 is enabled in response to the first control signal VCON1, the first connector 200 is driven to adjust the current of the first LED module MD1. When the second second connection part 300 is enabled in response to the second control signal VCON2, the second second connection part 300 is driven to adjust currents of the first LED module MD1 and the second LED module MD2.

As described above, the possibility of occurrence of transient currents in the first LED module MD1 and the second LED module MD2 is reduced by the effects of the first and second connection parts 200 and 300.

In detail, the first connection part 200 includes a first switching element 210, a first comparison element 220, and a first resistance element 230. Preferably, the first switching element 210 is an NMOS transistor formed between the first connection node NC1 and the first feedback node NFB1. In this case, the conductance of the first switching element 210 is controlled according to the voltage of the first comparison signal XCOM1. In the present embodiment, the lower the voltage of the first comparison signal XCOM1 is, the lower the conductance of the first switching element 210 is. In other words, as the voltage of the first comparison signal XCOM1 is lower, the resistance component of the first switching element 210 increases.

In the present exemplary embodiment, the first switching element 210 has a source terminal connected to the first feedback node NFB1, a drain terminal connected to the first connection node NC1, and a gate terminal connected to the first terminal. The NMOS transistor is connected to the comparison signal XCOM1.

The first comparison element 220 generates the first comparison signal XCOM1 by comparing the voltage of the first feedback node NFB1 with the first reference voltage Vref1. At this time, as the voltage of the first feedback node NFB1 increases, the voltage level of the first comparison signal XCOM1 decreases.

The first resistor element 230 is formed between the first feedback node NFB1 and the ground voltage VBAS. In this case, the first resistance element 230 has a relatively low resistance value. Accordingly, the first feedback node NFB1 is controlled at a very low voltage level close to the ground voltage VBAS, that is, the ground voltage VSS.

Accordingly, in the LED lighting apparatus of FIG. 3, even if the first comparison signal XCOM1 is controlled at a very low voltage level, the first switching element 210 may achieve an appropriate switching operation.

The second connection part 300 also has a similar configuration and effect to the first connection part 200.

In detail, the second connection part 300 includes a second switching element 310, a second comparison element 320, and a second resistance element 330. Preferably, the second switching element 310 is an NMOS transistor formed between the second connection node NC2 and the second feedback node NFB2. In this case, the conductance of the second switching element 310 is controlled according to the voltage of the second comparison signal XCOM2. In the present embodiment, the lower the voltage of the second comparison signal XCOM2 is, the lower the conductance of the second switching element 310 is. In other words, as the voltage of the second comparison signal XCOM2 is lower, the resistance component of the second switching element 310 increases.

In the present exemplary embodiment, the second switching device 310 has a source terminal connected to the second feedback node NFB2, a drain terminal connected to the second connection node NC2, and a gate terminal connected to the second terminal. The NMOS transistor is connected to the comparison signal XCOM2.

The second comparison element 320 generates the second comparison signal XCOM2 by comparing the voltage of the second feedback node NFB2 with the second reference voltage Vref2. At this time, as the voltage of the second feedback node NFB2 increases, the voltage level of the second comparison signal XCOM2 decreases.

The second resistor 330 is formed between the second feedback node NFB2 and the ground voltage VBAS. Accordingly, the first feedback node NFB1 is controlled at a very low voltage level close to the ground voltage VBAS, that is, the ground voltage VSS.

Thus, similarly to the first comparison signal XCOM1, the second switching element 310 may achieve an appropriate switching operation even though the second comparison signal XCOM2 is controlled at a very low voltage level.

Preferably, the first reference voltage Vref1 and the second reference voltage Vref2 have the same voltage level.

Subsequently, the process of reducing the transient current that may be generated in the LED modules included in the respective closed circulation current loops by the first and second connectors 200 and 300 will be described.

First, when the number of LED elements of the LED module is smaller than the designed value, or when the resistance of the LED element is smaller than the designed value, a transient current may occur in the LED module. In addition, even when the supplied AC voltage VAC becomes higher than the allowable level and the rectified voltage VREC becomes higher than the allowable level, a transient current may occur in the corresponding LED module.

In this case, the voltages of the corresponding feedback nodes NFB1 and NFB2 become higher than the designed values. Then, the voltage level of the corresponding comparison signal (XCOM1, XCOM2) is lowered, the resistance component of the corresponding switching element (210, 310) is increased. Thus, the transient current of the LED module included in the closed loop current loop is reduced.

According to the LED lighting apparatus of the present invention as described above, the voltage level near the ground voltage is connected to the source terminal of the first and second NMOS transistors implementing the switching element. Accordingly, although the first comparison signal and the second comparison signal applied to the gate terminals of the first and second NMOS transistors are controlled at a low voltage level, the first and second NMOS transistors serve as switching elements. Can be performed stably.

Therefore, according to the LED lighting apparatus of the present invention, the transient current of the LED module included in the closed loop current loop, while improving the complexity of the circuit structure and operation characteristics such as power efficiency, power factor, etc., without the use of capacitors, inductors, and PFC ICs. Is reduced.

In addition, in the LED lighting apparatus of the present invention, when the gate terminal of the NMOS transistor is applied with a low voltage level, the possibility of breakage of the NMOS transistor is significantly reduced, and the overall reliability is greatly improved.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (6)

In the LED lighting device,
A rectifier generation block for generating a rectified voltage, the rectified voltage comprising: the rectified generation block having a driving voltage difference in one direction with respect to a predetermined ground voltage;
A first LED module formed between the rectified voltage and a first connection node;
A second LED module formed between the first connection node and the second connection node;
A first connection part electrically connecting the first connection node to the ground voltage in response to a first control signal, the first connection part being driven to regulate current of the first LED module and the second LED module;
A second connector driven to electrically connect the second connection node to the ground voltage in response to a second control signal; And
And a control block for generating the first control signal and the second control signal controlled in a state corresponding to the magnitude of the driving voltage difference.
The first connection portion
A first switching element formed between the first connection node and a first feedback node, the first switching element having conductance controlled according to a voltage of a first comparison signal;
A first comparison element generating the first comparison signal by comparing the voltage of the first feedback node with a predetermined reference voltage; And
And a first resistance element formed between the first feedback node and the ground voltage.
delete The method of claim 1, wherein the first switching device
And an NMOS transistor having a source terminal connected to the first feedback node, a drain terminal connected to the first connection node, and a gate terminal connected to the first comparison signal.
The method of claim 1, wherein the second connection portion
And the second connection node is electrically connected to the ground voltage in response to the second control signal, the LED lighting device being driven to adjust the current of the first LED module and the second LED module.
The method of claim 4, wherein the second connecting portion
A second switching element formed between the second connection node and a second feedback node, the second switching element having conductance controlled according to a voltage of a second comparison signal;
A second comparison element configured to generate the second comparison signal by comparing the voltage of the second feedback node with a predetermined reference voltage; And
And a second resistance element formed between the second feedback node and the ground voltage.
The method of claim 5, wherein the second switching element
And an NMOS transistor having a source terminal connected to the second feedback node, a drain terminal connected to the second connection node, and a gate terminal connected to the second comparison signal.

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