KR20180013315A - LED lighting apparatus and LED driving circuit thereof - Google Patents

Abstract

An LED lighting apparatus according to an embodiment of the present invention comprises: a rectifier rectifying an AC voltage input from an external power source to generate a driving voltage; an LED lighting unit including a first LED group connected to a first node connected to an output terminal of the rectifier and a plurality of LED groups connected in series to the first LED group; a switch unit controller receiving the driving voltage to generate a voltage value associated with the external power source and comparing the generated voltage value with a preset reference voltage value to output a control signal; a switch unit connected between the first node and a second node positioned between the LED groups and being controlled to be turned on/off by the control signal to change connection relations of the LED groups; and a driving current controller connected to each of the LED groups and configured to control a driving current flowing in each of the LED groups at a constant current.

Description

[0001] The present invention relates to an LED lighting apparatus and an LED driving circuit,

An embodiment of the present invention relates to an AC-driven LED lighting device and an LED driving circuit included therein.

Generally, in order to drive an LED lighting device using an AC voltage, an AC voltage is converted into a rectified voltage and a circuit is configured to adjust the number of LED light emitting devices to emit as the magnitude of the rectified voltage varies.

In this case, as the magnitude of the rectified voltage fluctuates, a part of the plurality of LED light emitting devices continuously emits light and is determined to be lengthened, while a part of the remainder is limitedly emitted only when the magnitude of the rectified voltage exceeds a certain size So that the light emission time differs for each of the LED light emitting elements constituting the lighting apparatus. As a result, some of the LED light emitting elements may be deteriorated first, resulting in a problem that the dimming state of the lighting apparatus becomes poor or the operation of the lighting apparatus becomes impossible in a serious case.

Also, the voltage levels of the commercial AC power supplied by each country are different. For example, 220V (rms) AC power is supplied in Korea, but 120V (rms) AC power or 277V (rms) AC power can be supplied in other countries. In order to drive the LED lighting device irrespective of the voltage level of the supplied commercial AC power supply, additional circuits capable of performing a universal voltage function must be added to the LED lighting device.

It is an object of the present invention to provide an LED lighting device and a driving circuit thereof that can realize a universal voltage function without additional additional circuit by controlling a connection relation between LED groups so as to correspond to input commercial AC power.

According to an aspect of the present invention, there is provided an LED lighting device including: a rectifier for rectifying an AC voltage input from an external power source to generate a driving voltage; A first LED group connected to a first node connected to the output terminal of the rectifier, and a plurality of LED groups connected in series with the first LED group; A switch unit controller receiving a driving voltage and generating a voltage value associated with the external power source, comparing the generated voltage value with a predetermined reference voltage value, and outputting a control signal; A switch unit connected between the first node and a second node positioned between the LED groups, the switch unit being turned on / off by the control signal to change the connection relationship of the LED groups; And a driving current controller connected to each of the LED groups and configured to control the driving current flowing in each LED group by a constant current.

Also, the external power source is one of commercial AC power sources having different effective voltage values.

The second node is a node between the cathode terminal of the first LED group and the anode terminal of the adjacent second LED group, and further includes a diode between the cathode terminal of the first LED group and the second node.

The switch unit controller may further include: a resistor and a capacitor connected in series between the first node and the ground; And a comparator to which the voltage of the capacitor is applied to the negative input terminal, the reference voltage is applied to the positive input terminal, and the comparator outputs the control signal.

Also, the voltage of the capacitor has a different voltage level for each of the commercial AC power sources corresponding to the input commercial AC power sources, and the reference voltage is set to an arbitrary effective voltage value between the commercial AC power sources do.

The switch unit may include: a control transistor controlled by a control signal output from the switch control unit; And a switching transistor connected between the first node and the second node and having a gate electrode connected to the first electrode of the control transistor.

The control transistor is connected between the gate electrode of the switch transistor and the ground, the control signal is applied to the gate electrode, a resistance connected between the drain electrode and the gate electrode of the switching transistor, And a zener diode connected thereto.

Also, the LED driving circuit according to the embodiment of the present invention receives a driving voltage generated by rectifying external power, generates a voltage value associated with the external power source, compares the generated voltage value with a predetermined reference voltage value A switch unit controller for outputting a control signal; A switch unit connected between a first node to which the driving voltage is applied and a second node between the LED groups and to be turned on and off by the control signal to change a connection relationship of the LED groups; And a driving current controller connected to each of the LED groups and configured to control the driving current flowing in each LED group by a constant current.

According to the present invention, a universal voltage function can be realized by controlling the connection relationship between the LED groups so as to correspond to the input commercial AC power, without additional circuitry.

1 is a block diagram of an LED lighting apparatus according to an embodiment of the present invention;
2 is a schematic circuit diagram of an LED lighting apparatus according to an embodiment of the present invention.
Fig. 3 is a schematic circuit diagram illustrating the operation of the drive current controller shown in Fig. 1. Fig.
Fig. 4 is a schematic circuit diagram illustrating the operation of the switch unit controller shown in Fig. 1. Fig.
5 is a schematic circuit diagram illustrating the operation of the switch unit shown in Fig.
FIG. 6A is a block diagram illustrating an operation when an LED lighting apparatus according to an embodiment of the present invention is connected to a 120V (rms) AC power source. FIG.
6B is a waveform diagram showing a relationship between a rectified voltage and an LED driving current when the LED lighting apparatus according to the embodiment of the present invention is connected to a 120V (rms) AC power source.
FIG. 7A is a block diagram for explaining an operation when the LED lighting apparatus according to the embodiment of the present invention is connected to a 220V (rms) AC power source. FIG.
7B is a waveform diagram showing a relationship between a rectified voltage and an LED driving current when the LED lighting apparatus according to the embodiment of the present invention is connected to a 220V (rms) AC power source.

It is to be understood that the description in the technical field of the background of the present invention is only for the understanding of the background art on the technical idea of the present invention and therefore it can be understood that it corresponds to the prior art known to a person skilled in the art none.

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various embodiments. It will be apparent, however, that the various embodiments may be practiced without these specific details, or with one or more equivalents. In other instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the various embodiments unnecessarily.

In the drawings, the sizes or relative sizes of layers, films, panels, regions, etc. may be exaggerated for clarity. Also, like reference numerals designate like elements.

Throughout the specification, if an element or layer is described as being "connected" to another element or layer, it is not only directly connected but also indirectly connected with another element or layer in between . However, if a part is described as "directly connected" to another part, it will mean that there is no other element between that part and the other part. At least one selected from the group consisting of "X, Y and Z and at least one selected from the group consisting of X, Y and Z" is X, Y, Z, (E.g., XYZ, XYY, YZ, ZZ). Herein, "and / or" includes all combinations of one or more of the corresponding configurations.

The terms first, second, etc. may be used herein to describe various elements, elements, regions, layers, and / or sections, Or sections are not limited to these terms. These terms are used to distinguish one element, element, region, layer, and / or section from another element, element, region, layer, and / or section. Thus, a first element, element, region, layer, and / or section in one embodiment may be referred to as a second element, element, region, layer, and / or section in another embodiment.

Spatially relative terms such as "below "," above ", and the like can be used for illustrative purposes, thereby describing the relationship between one element or feature and another element (s) or feature (s) do. This is used to denote the relationship of one component to another in the drawings, but not to an absolute position. For example, if the device shown in the figures is inverted, the elements depicted as being "below" other elements or features are positioned in the "up" direction of other elements or features. Thus, in one embodiment, the term "below" may include both upward and downward directions. In addition, the device may be in another direction (e.g., rotated 90 degrees or in another direction), and such spatially relative terms used herein are interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Throughout the specification, when a component is referred to as "comprising ", it means that it can include other components as well, without departing from the other components unless specifically stated otherwise. Unless defined otherwise, terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

FIG. 1 is a block diagram of an LED lighting apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of an LED lighting apparatus according to an embodiment of the present invention.

1 and 2, an LED lighting apparatus 1000 according to an embodiment of the present invention includes a rectifier 100, an LED light emitting unit 200, a switch unit 300, a switch unit controller 400, (500).

The LED light emitting unit 200 may include a plurality of LED groups 200a, 200b, and 200c. The LED groups 200a, 200b, and 200c included in the LED light emitting unit 200 may be controlled in connection with each other according to the operation of the switch unit 300. Also, when the LED groups 200a, 200b, 200c are connected in series, the LED groups connected in series according to the operation of the current controller 500 may be sequentially driven.

1, the LED light emitting unit 200 includes three LED groups 200a to 200c. However, the LED light emitting unit 200 may be included in the LED light emitting unit 200 It will be apparent to those skilled in the art that the number of LED groups to be varied may vary.

Hereinafter, for convenience of explanation and understanding, the LED light emitting unit 200 will be described based on an embodiment including three LED groups, but the present invention is not limited thereto. For example, the LED light emitting unit 200 may include n LED groups (n is a positive integer of 2 or more) from the first LED group 200a to the nth LED group (not shown).

On the other hand, the first LED group 200a to the third LED group 200c may have the same forward voltage level or may have different forward voltage levels from each other. For example, when the first LED group 200a to the third LED group 200c are each configured to include a different number of LED elements, or when the first LED group 200a to the third LED group 200c are configured in different ways The first LED group 200a to the third LED group 200c may have different forward voltage levels when they have a serial or parallel or serial / parallel connection relationship.

Hereinafter, for convenience of explanation and understanding, the first LED group 200a to the third LED group 200c are all configured to have the same forward voltage level.

For example, the first forward voltage level Vf1 may be a threshold voltage level capable of driving the first LED group 200a, the second forward voltage level Vf2 may be the first LED group 200a connected in series, (I.e., the voltage level of the forward voltage level of the first LED group plus the forward voltage level of the second LED group) capable of driving the two LED groups 200b, and the third forward voltage level Vf3 is And may be a threshold voltage level capable of driving the first through third LED groups 200a, 200b, and 200c connected in series.

The rectifier 100 is configured to rectify an _AC voltage V _AC input from the external power supply 10 to generate and output a rectified voltage, and the rectified voltage is applied to a driving voltage V _in ). The rectifier 100 may be a rectifier circuit well known in the art such as a diode bridge circuit consisting of diodes d1, d2, d3 and d4 as shown in Fig. The external power source 10 may be a commercial AC power source, and the commercial AC power source may be a voltage of 120V (rms), 220V (rms), or 277V (rms).

The switch unit controller 400 receives the driving voltage V _in to generate a voltage value associated with the commercial AC power source 10 connected to the LED lighting apparatus 1000 and outputs the generated voltage value to a predetermined reference voltage value And outputs a control signal CS for controlling the operation of the switch unit 300. [ The switch unit controller 400 may directly receive the _AC voltage V _AC input from the external power supply 10 _in addition to the driving voltage V _in .

The switch unit controller 400 includes a first resistor R1 and a capacitor C connected in series between a first node N1 connected to the output terminal of the rectifier 100 and the ground, And a second resistor R2 and a zener diode dz that are connected in parallel to the capacitor C, respectively. The comparator further includes a comparator for receiving a voltage applied to the capacitor (C) as a negative input terminal (-). At this time, a reference voltage is applied to the positive input terminal (+) of the comparator, and the reference voltage may be generated through the regulator (G). The regulator G may be implemented as a shunt regulator and may be connected in parallel with the DC power source V _DC through a resistor r 1 connected in series. A full-up resistor r2 is connected to the output terminal of the comparator. The DC power supply V _DC shown in FIG. 2 serves to provide an operation voltage for operating the comparator and the regulator G can do. In addition, the first resistor R1 and the second resistor R2 serve to divide the input voltage to be detected, and the Zener diode dz can protect the comparator from an input overvoltage.

The switch unit 300 performs a turn-on / turn-off operation by the control signal CS. As shown in the figure, the switch unit 300 is connected between the first node N1 and the second node N2 Respectively. In this case, the first node N1 is a node connected to the output terminal of the rectifier 100, and the second node N1 may be a node between the LED groups 200a, 200b, and 200c.

The switch unit 300 includes resistors RZ and RZ connected between the gate electrodes of the first node N1 and the gate of the transistor QW and the transistors QW and QS of different types as shown in FIG. And a zener diode DZ.

1, when the switch unit 300 is turned off, the driving voltage V _in output from the rectifier 100 is applied to the first LED group 200a through the third LED 200a connected in series, Group 200c and sequentially driven according to the voltage level of the driving voltage V _in .

For example, only the first LED group 200a is driven in a period (first operation period) _in which the voltage level of the driving voltage V _in is lower than the first forward voltage level Vf1 and lower than the second forward voltage level Vf2, The first LED group 200a and the second LED group 200b are turned on during a period _in which the voltage level of the driving voltage V _in is lower than the second forward voltage level 2Vf and lower than the third forward voltage level Vf3 The first LED group 200a, the second LED group 200b, and the second LED group 200b are driven in a period (third operation period) _{in which} the driving voltage V _in is higher than the third forward voltage level Vf3, Both the third LED group 200c are driven.

On the other hand, when the switch unit 300 is turned on, the driving voltage V _in is applied to the second LED group 200a connected to the second node N2 as well as the first LED group 200a connected to the first node N1 200b. In the embodiment shown in FIG. 1, the second node N2 may be a node between a cathode end of the first LED group 200a and an anode end of the second LED group 200b. In order to prevent a reverse current path from being generated when the driving voltage V _in is applied to the second node N2, the cathode terminal of the first LED group 200a and the cathode terminal of the second node N2 A diode D1 may be provided between the diode D1 and the diode D1.

When the driving voltage V _in is applied to the LED light emitting unit 200 through two paths, the LED light emitting unit 200 is divided into two sets, and each LED group corresponding to each set And is sequentially driven according to the voltage level of the applied driving voltage V _in . The 'set' means at least one LED group connected in series to form one unit.

For example, when the second LED group 200b and the third LED group 200c become one set, they are sequentially driven in the set. That is, only the second LED group 200b is driven in a period (first operation period) _in which the voltage level of the driving voltage V _in is lower than the first forward voltage level Vf1 and lower than the second forward voltage level Vf2, The second LED group 200b and the third LED group 200b are turned off during a period _in which the voltage level of the driving voltage V _in is lower than the second forward voltage level Vf2 and lower than the third forward voltage level Vf3 200c may be driven.

Also, the first LED group 200a, which is separated into a separate set, may be driven during the first operation period and the second operation period.

The current control unit 500 includes a plurality of driving current controllers 500a, 500b, and 500c. In the embodiment shown in FIG. 1, the first to third driving current controllers 500a, 500b and 500c are connected to the cathode ends of the first LED group 200a to the third LED group 200c, respectively . The target voltage Vt may be applied to each of the drive current controllers 500a, 500b and 500c and may be applied to the first to third drive current controllers 500a, 500b and 500c according to the target voltage Vt. The amounts of electric currents of the first to third LED groups 200a, 200b and 200c connected to each other are determined. Accordingly, the first to third driving current controllers 500a, 500b and 500c perform the operation of controlling the first to third driving currents flowing through the first to third LED groups 200a, 200b and 200c with a constant current can do. In this case, the target voltage Vt may be set differently for each of the drive current controllers 500a, 500b, and 500c. In this case, the first to third drive currents may be constant current controlled according to a preset value.

Each of the drive current controllers 500a, 500b, and 500c may include a transistor Qd, a sense resistor Rd, and a linear amplifier as shown in FIG.

The LED lighting apparatus 1000 according to an embodiment of the present invention detects a voltage level corresponding to an inputted commercial AC power source 10 and detects the voltage level of the LED light emitting element groups 200a, 200b, and 200c according to the detected voltage level. So that the universal voltage function can be realized without any additional circuit.

The switch unit controller 400, the switch unit 300 and the current controller 500 may be integrated into a single IC to receive the driving voltage V _in , It is possible to perform the function of the LED driving circuit for driving the LED driving circuit.

The embodiments of the current controller 500, the switch unit controller 400 and the switch unit 300 among the constituent elements of the LED driver circuit and their operation will be described with reference to FIG. 3 to FIG.

3 is a schematic circuit diagram illustrating the operation of the drive current controller shown in Fig. 3, the first driving current controller 500a is described as an example, but the second and third driving current controllers may be similarly configured.

Referring to FIG. 3, the driving current controller 500a includes a linear amplifier 520, a transistor Qd, and a detection resistor Rd. The voltage detected by the detection resistor Rd is applied to the negative input terminal of the linear amplifier 520, and the target voltage Vt described above may be applied to the positive input terminal.

The output of the linear amplifier 520 may be input to the gate electrode of the transistor Qd. The transistor Qd may be variously implemented as a switching element for constant current control. The transistor Qd is connected between the cathode terminal of each of the LED groups 200a, 200b and 200c and the detection resistor Rd and is turned on / off according to the output of the linear amplifier 520 applied to the gate electrode. .

If the detection voltage at the detection resistor Rd is less than the target voltage Vt, the linear amplifier 520 outputs a high level voltage (that is, , A voltage having a positive value), which is applied to the gate electrode of the transistor Qd.

In one embodiment, the first driving current controller 500a may operate in a period (first operation period) _in which the voltage level of the driving voltage V _in is lower than the first forward voltage level 1Vf and the second forward voltage level 2Vf, Will be described.

The first LED group 200a is turned on between the first operation group and the first driving current control unit 500a connected to the first LED group 200a is also activated to turn on the first LED group 200a 1 LED current I _LED1 is applied to the detection resistor Rd of the first driving current control part 500a. The linear amplifier 520 compares the detection voltage input to the negative input terminal with the target voltage Vt input to the positive input terminal and outputs the first gate input voltage V _G1 corresponding to the difference to the transistor Qd). If the above-mentioned detection voltage is less than the target voltage (Vt) as said voltage V _G1 has a voltage value of a high level.

Turn in this case said transistor (Qd) voltage (V _GS) is the first gate input voltage becomes variable by (V _G1), the transistors (Qd) in accordance with the V _GS voltage between the gate electrode and the source electrode on / Off state is determined.

More specifically, when the V _GS voltage rises due to the application of V _G1 having the voltage value of the high level, the amount of the first LED current flowing through the detection resistor Rd through the transistor Qd increases. However, when the detection voltage in the detection resistor Rd is increased by the increased current amount, the magnitude of the voltage V _G1 is reduced, and the first LED current amount decreases correspondingly.

That is, the voltage at the detection resistor Rd has a characteristic to follow the target voltage Vt, thereby controlling the first LED current I _LED1 to a constant current.

4 is a schematic circuit diagram illustrating the operation of the switch unit controller shown in Fig. However, FIG. 4 shows only the basic configuration for explaining the operation of the switch unit controller, and other components may be further included.

4, the switch unit controller 400 includes a voltage generator (not shown) for receiving the driving voltage V _in and generating a voltage Vc associated with the commercial AC power source 10 connected to the LED lighting apparatus 1000 And a comparator 420 for comparing the generated voltage Vc with a predetermined reference voltage V _REF and outputting a control signal CS for controlling the operation of the switch unit 300. However, the voltage input to the voltage generator 410 is not limited to the driving voltage V _in , and the AC voltage V _AC input from the external power source 10 may be directly input.

The switch unit controller 400 detects the specification of the commercial AC power supply 10 connected to the LED lighting apparatus 2000 to realize the above-mentioned universal voltage function, The connection relationship of the first LED group 200a to the third LED group 200c is controlled so that the light emitting unit 200 is smoothly driven.

For example, the LED light emitting unit 200 including the first to third LED groups 200a, 200b, and 200c may have a first forward voltage level Vf1 of 60V, a second forward voltage level Vf2) and a third forward voltage level (Vf3) of 160V. In this case, when the AC driving LED lighting apparatus 1000 is connected to 220 V (rms) or 277 V (rms) AC power, the first LED group to the third LED group 200a, 200b and 200c are connected in series The first LED group to the third LED group 200a, 200b and 200c may be connected in series to each other when the AC-driven LED lighting device 1000 is connected to an AC power source of 120V (rms). Can not operate all connected. That is, when connected to the AC power source of 120V (rms), the third LED group 200c among the first to third LED groups 200a, 200b and 200c connected in series does not emit light continuously .

Conversely, a connection is established so as to be divided into a first set of LED groups (first LED group 200a) and a second set of LED groups (a second LED group 200b and a third LED group 200c connected in series with each other) If the relationship is controlled, there is a problem that the power efficiency is lowered when 220 V (rms) or 277 V (rms) AC power is connected.

In order to overcome this, an embodiment of the present invention receives a rectified voltage as a driving voltage V _in , generates a voltage Vc associated with the commercial AC power source 10 connected to the LED lighting apparatus 1000, It is possible to determine the size of the currently connected commercial AC power source by comparing it with the reference voltage V _REF .

The voltage generator 410 includes a resistor R and a capacitor C connected in series between the first node N1 and the ground, as shown in FIG. A driving voltage V _in is applied to the first node N1. That is, the voltage generator 410 performs the operation of the low pass filter (LPF) to output the voltage Vc of the capacitor C to the negative input terminal of the comparator 420. The voltage generator 410 may generate a voltage signal Vc that maintains a constant level by converting the waveform of the input AC voltage. The level of the generated voltage may be controlled by adjusting values of R and C included in the voltage generator 410, that is, a time constant.

More specifically, the driving voltage V _in may be input in different waveforms according to the external power supply 10, that is, a commercial AC power source. The voltage Vc generated by the voltage generating unit 410 is input to the input And have voltage values at different levels corresponding to the commercial AC power source.

For example, when an AC power of 120V (rms) is inputted, a signal Vc1 having a first voltage level is generated, and when a 220V (rms) AC power is inputted, a signal Vc2 having a second voltage level is generated , And 277V (rms), the signal Vc3 having the third voltage level can be generated.

Therefore, the voltage Vc generated by the voltage generating unit 410 is a voltage associated with the input commercial AC power, so that the input AC power can be determined through the voltage Vc.

According to the above-described embodiment, when the 220V (rms) or 277V (rms) AC power source is connected, the first LED group to the third LED group 200a, 200b and 200c are sequentially connected (First LED group 200a) and the second set of LED groups (the second LED group 200b connected in series with each other and the third LED group 200b connected in series with each other) Group 200c), as shown in FIG.

According to the configuration of the switch unit controller 400 shown in FIG. 4, the driving voltage V _in is received and a voltage Vc associated with the commercial AC power source connected to the LED lighting apparatus 1000 is generated. (Vc) with a preset reference voltage (V _REF ) and control the operation of the switch unit (300) according to the result.

Here, the reference voltage V _REF may be a value corresponding to a specific effective voltage of the commercial AC power source for controlling the connection relationship of the first LED group to the third LED group 200a, 200b, and 200c. That is, the LED lighting apparatus 1000 may be configured such that the connected AC power source is large enough to drive the first to third LED groups 200a, 200b, and 200c in series with each other, It can be configured to determine only whether the groups 200a, 200b, 200c are small enough to be driven into a plurality of sets, and to control the operation of the switch unit 300 based on such determination.

For example, in the case of the above-described example (the LED light emitting section 200 has a first forward voltage level Vf1 of 60 V, a second forward voltage level Vf2 of 120 V, and a third forward voltage level Vf3 of 160 V The first LED group to the third LED group 200a, 200b, and 200c may be driven in series and connected to each other when the connected AC power source is 220V (rms) or 277V (rms) (First LED group 200a) and the second set of LED groups (the second LED group 200b and the third LED group 200b connected in series with each other) when the AC power source is 120V (rms) 200c).

For example, the reference voltage V _REF may be set to correspond to any reference effective voltage (for example, 200V (rms)) between 120V (rms) and 220V (rms) Vc2, and Vc3) generated by the commercial AC power source (400, 400).

The output signal CS of the comparator 420 has a high level voltage when the generated voltage is a voltage Vc1 corresponding to an AC power source of 120 V (rms), which is smaller than the level of the reference voltage _VREF . On the other hand, if the generated voltage is a voltage Vc2 or Vc3 corresponding to an alternating current of 220 V (rms) or 277 V (rms), it is greater than the level of the reference voltage V _REF and the output signal CS of the comparator 420, Has a low level voltage value.

5 is a schematic circuit diagram illustrating the operation of the switch unit shown in Fig.

5, the switch unit 300 includes a control transistor QS controlled by a control signal CS output from the switch control unit 400, a first node N1 and a second node N2 And a gate electrode connected to a first electrode of the control transistor QW. The control transistor QS and the switching transistor QW are preferably MOSFETs and can be selectively used as the n-type or p-type conductivity type. In an embodiment of the present invention, the switching transistor QW is implemented as an n-MOSFET and the control transistor QS is implemented as a p-MOSFET.

The drain electrode of the switching transistor QW may be connected to the driving voltage V _in through the first node N1 and the resistor RZ may be connected between the drain electrode and the gate electrode. The switching operation of the switching transistor QW can be performed in the cutoff state of the control transistor QS through the resistor RZ.

In addition, a zener diode DZ may be further provided in parallel with the resistor RZ. The Zener diode DZ can perform a function of clipping the surge voltage having a high high voltage instantaneously to the gate electrode at a predetermined level.

The source electrode of the switching transistor QW is connected to the second node N2 and the second node N2 is connected to the cathode terminal of the first LED group 200a and the cathode terminal of the second LED group 200b Lt; RTI ID = 0.0 > anode < / RTI >

The control transistor QS is connected between the gate electrode of the switch transistor QW and ground, and the control signal CS output from the switch control unit 400 is applied to the gate electrode.

Hereinafter, the operation of the switch unit 300 is controlled by the control signal CS.

The control transistor QS is turned on and the switching transistor QW is turned on when the control signal CS is low. Is applied with a low level voltage by a current path connected to the ground, so that the switching transistor QW is turned off. When the switching transistor QW is turned off, the first to third LED groups 200a, 200b and 200c are connected to each other in series.

On the other hand, when the control signal CS is at a high level, for example, when the input AC power is determined to be 120V (rms), the control transistor QS is turned off. In addition, a voltage of a predetermined level is applied to the switching transistor QW by the resistor RZ connected between the gate electrode and the drain electrode of the switching transistor QW. In particular, due to the control transistor QS in the cut-off state, the drive voltage V _in and the current path through the resistor RZ are cut off. Therefore, since the gate electrode of the switching transistor QW is applied with substantially the same level as the driving voltage V _in , the switching transistor QW is turned on. When the switching transistor QW is turned on, the first set of LED groups (the first LED group 200a) and the second set of LED groups (the second LED group 200b and the third LED group 200b, (200c)).

FIG. 6A is a block diagram illustrating an operation when the LED lighting apparatus according to an embodiment of the present invention is connected to a 120V (rms) AC power source, FIG. 6B is a diagram illustrating an operation of the LED lighting apparatus according to the embodiment of the present invention, FIG. 7 is a waveform chart showing a relationship between a rectified voltage and an LED driving current when the LED is connected to an AC power source.

6A and 6B, as described above, the LED light emitting portion 200 is divided into the first forward voltage level Vf1 of 60 V, the second forward voltage level Vf2 of 120 V, And a forward voltage level Vf3.

Hereinafter, an operation of the LED lighting apparatus 1000 connected to the 120 V (rms) AC power supply will be described with reference to FIGS. 6A and 6B.

As described above, the 120V (rms) AC power supply can not sequentially drive the first to third LED groups 200a, 200b, and 200c in a state where they are connected to each other in series. Accordingly, when the 120V (rms) AC power source is connected, the switch unit 300 is turned on by the switch unit controller 400 so that one set of LED groups (the first LED group 200a) and the second set of LEDs Group (the second LED group 200b to the third LED group 200c) is maintained.

In this state, the relationship between the driving voltage V _in and the LED driving current I _LED1 flowing through the first set of LED groups, that is, the first LED group 200a, is shown at the top of FIG. 6B, the lower end of 6b, the driving voltage (V _in) and LED groups of the second set, that is, in series a second LED group (200b) and the 3 LED groups (200c) the LED drive current (I _LED2, which flows through I are connected to each other _LED3 ) are shown.

As can be seen at the top and bottom of Figure 6b, the first set of LED groups and the second set of LED groups are controlled independently of each other. In particular, it can be seen that the second LED group 200b and the third LED group 200c belonging to the second set of LED groups are sequentially driven according to the voltage level of the driving voltage V _in .

6A and 6B, the driving voltage V _in is applied to the first LED group 200a connected to the first node N1 and the second LED group 200b connected to the second node N2, (200b).

When the driving voltage V _in is applied to the LED light emitting unit 200 through two paths, the LED light emitting unit 200 is divided into two sets, and each LED group corresponding to each set And is sequentially driven according to the voltage level of the applied driving voltage V _in .

That is, in the period (the first operation period, t1 to t2, t3 to t4) where the voltage level of the driving voltage V _in is lower than the first forward voltage level 1Vf and lower than the second forward voltage level 2Vf, Only the group 200b is driven to cause the second LED current I _LED2 to flow (② in Fig. 6A).

(Second operation period t2 to t3) _in which the voltage level of the drive voltage V _in is lower than the second forward voltage level 2Vf and lower than the third forward voltage level 3Vf, The third LED group 200c is driven and the third LED current I _LED3 flows (3 & cir & in Fig. 6A).

In addition, the first LED group 200a, which is separated into a separate set, is driven during the first and second operation periods t1 to t4 to flow the first LED current I _LED1 (1 in Fig. 6A).

FIG. 7A is a block diagram illustrating an operation when the LED lighting apparatus according to the embodiment of the present invention is connected to a 220V (rms) AC power source, FIG. 7B is a diagram illustrating an operation of the LED lighting apparatus according to the embodiment of the present invention, FIG. 7 is a waveform chart showing a relationship between a rectified voltage and an LED driving current when the LED is connected to an AC power source.

7A and 7B, as described above, the LED light emitting portion 200 is divided into the first forward voltage level Vf1 of 60 V, the second forward voltage level Vf2 of 120 V, 3 forward voltage level (Vf3).

Hereinafter, the operation of the LED lighting apparatus 1000 connected to the 220 V (rms) AC power supply will be described with reference to FIGS. 7A and 7B.

As described above, the 220V (rms) AC power source can sequentially drive the first to third LED groups 200a, 200b and 200c in a state where they are connected to each other in series.

Accordingly, when the 220V (rms) AC power supply is connected, the switch unit 300 is turned off by the switch unit controller 400, and the first LED group to the third LED group 200a, 200b, And is sequentially driven. This process is illustrated in Figures 7A and 7B.

When the switch unit 300 is turned off, the driving voltage V _in output from the rectifier 100 is sequentially applied to the first LED group 200a to the third LED group 200c connected in series, And is sequentially driven according to the voltage level of the voltage V _in .

(T1 'to t2', t5 'to t6') _in which the voltage level of the driving voltage V _in is lower than the first forward voltage level 1Vf and lower than the second forward voltage level 2Vf, Only the first LED group 200a is driven to flow the first LED current I _{LED1 '} (1 &_apos; in Fig. 7A).

(Second operation period, t2 'to t3', t4 'to t5') _in which the voltage level of the drive voltage V _in is lower than the second forward voltage level (2Vf) and lower than the third forward voltage level (3Vf) The LED group 200a and the second LED group 200b are driven to cause the second LED current I _{LED2 '} to flow (②' in FIG. 7A).

The first LED group 200a, the second LED group 200b, and the third LED group 200b are turned on during a period (third operation period, t3 'to t4') where the voltage level of the driving voltage V _in is equal to or higher than the third forward voltage level 3Vf The third LED group 200c is driven and the third LED current I _{LED3 '} flows (③' in FIG. 7A). Further, in the embodiment of the present invention, The LED drive current (I _LED ) can be controlled by the AC power source so that the LED drive current (I _LED ) can be maintained within about 30%. For example, 220V (rms) LED lighting device 1000 of the LED driving current (I _LED ') is a 120V (rms) LED drive current (I _LED) of the LED lighting device 1000 is connected to the AC power to the AC power source The constant current can be controlled at about 1/2 of 6A and 6B show the first LED driving current I _LED1 , the second LED driving current I _LED2 and the third LED driving current I _LED3 of the LED lighting apparatus 1000 connected to the 120V (rms) 7A and 7B show the first LED driving current I _LED1 ', the second LED driving current I _LED2 ' and the third LED driving current I _LED2 'of the LED lighting apparatus 1000 connected to the 220 V (rms) The LED drive current I _LED3 'is shown.

6B and 7B, the size of the first LED driving current I _LED1 ', the size of the second LED driving current I _LED2 ', and the third LED driving current I _LED2 'when connected to the 220 V (rms) (I _LED3 ') of the size of each of 120V (rms) magnitude and a 3 LED drive current of the size, the 2 LED drive current (I _LED2) of claim 1 LED drive current (I _LED1) when connected to the AC power source (I of _LED3) can be confirmed that the constant current control in about one-half the size of the size.

As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and specific embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

10: external power source 100: rectifier
200: LED light emitting unit 300: switch unit
400: switch unit control unit 500: drive current controller
1000: LED lighting device

Claims (20)

A rectifier for rectifying an AC voltage input from an external power supply to generate a driving voltage;
A first LED group connected to a first node connected to the output terminal of the rectifier, and a plurality of LED groups connected in series with the first LED group;
A switch unit controller receiving a driving voltage and generating a voltage value associated with the external power source, comparing the generated voltage value with a predetermined reference voltage value, and outputting a control signal;
A switch unit connected between the first node and a second node positioned between the LED groups, the switch unit being turned on / off by the control signal to change the connection relationship of the LED groups;
And a driving current controller connected to each of the LED groups and configured to control the driving current flowing in each of the LED groups. The method according to claim 1,
Wherein the external power source is one of commercial AC power sources having different effective voltage values. The method according to claim 1,
Wherein the second node is a node between a cathode end of the first LED group and an anode end of the second LED group adjacent thereto. The method of claim 3,
And a diode is further provided between the cathode end of the first LED group and the second node. The method according to claim 1,
The switch unit controller includes:
A resistor and a capacitor connected in series between the first node and ground;
And a comparator for comparing a voltage of the capacitor with a negative input terminal of the capacitor and applying the reference voltage to a positive input terminal of the comparator and outputting the control signal. 6. The method of claim 5,
Wherein the voltage of the capacitor has a different voltage value for each of the commercial AC power sources corresponding to input commercial AC power sources. The method according to claim 6,
Wherein the reference voltage is set to an arbitrary effective voltage value between the commercial AC power supplies. The method according to claim 1,
The switch unit includes:
A control transistor controlled by a control signal output from the switch control unit;
And a switching transistor connected between the first node and the second node and having a gate electrode connected to the first electrode of the control transistor. 9. The method of claim 8,
Wherein the control transistor is connected between the gate electrode of the switch transistor and the ground, and the control signal is applied to the gate electrode. 9. The method of claim 8,
A resistor connected between the drain electrode and the gate electrode of the switching transistor, and a zener diode connected in parallel with the resistor. A switch unit controller for receiving a driving voltage generated by rectifying external power, generating a voltage value associated with the external power source, comparing the generated voltage value with a predetermined reference voltage value, and outputting a control signal;
A switch unit connected between a first node to which the driving voltage is applied and a second node between the LED groups and to be turned on and off by the control signal to change a connection relationship of the LED groups;
And a driving current controller connected to each of the LED groups and configured to control the driving current flowing in each of the LED groups. 12. The method of claim 11,
Wherein the external power source is one of commercial AC power sources having different effective voltage values. The method according to claim 1,
Wherein the second node is a node between the cathode end of the first LED group and the anode end of the second LED group. 14. The method of claim 13,
And a diode is further provided between the cathode node of the first LED group and the second node. 12. The method of claim 11,
The switch unit controller includes:
A resistor and a capacitor connected in series between the first node and ground;
And a comparator for comparing a voltage of the capacitor with a negative input terminal of the capacitor, and applying the reference voltage to a positive input terminal of the comparator and outputting the control signal. 16. The method of claim 15,
Wherein the voltage of the capacitor has a different voltage level for each of the commercial AC power supplies corresponding to the input commercial AC power. 17. The method of claim 16,
Wherein the reference voltage is set to an arbitrary effective voltage value between the commercial AC power supplies. 12. The method of claim 11,
The switch unit includes:
A control transistor controlled by a control signal output from the switch control unit;
And a switching transistor connected between the first node and the second node and having a gate electrode connected to the first electrode of the control transistor. 19. The method of claim 18,
Wherein the control transistor is connected between the gate electrode of the switch transistor and the ground and the control signal is applied to the gate electrode. 19. The method of claim 18,
And a Zener diode connected in parallel with the resistor. The LED driving circuit according to claim 1, wherein the resistor is connected between the drain electrode and the gate electrode of the switching transistor.

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