WO2018021749A1 - Led lighting apparatus and led driving circuit therefor - Google Patents

Abstract

An LED lighting apparatus according to an embodiment of the present invention comprises: a rectifier for rectifying an alternating-current voltage that is input from an external power source, so as to generate a driving voltage; an LED light-emitting unit including a first LED group connected to a first node that is connected to an output terminal of the rectifier, and a plurality of LED groups connected to the first LED group in series; a switch unit controller which receives the driving voltage and generates a voltage value related to the external power source, and compares the generated voltage value with a pre-set reference voltage value and outputs a control signal; a switch unit connected between the first node and a second node that is located between the LED groups, wherein the turning on/off operation thereof is controlled by the control signal, thereby altering the connection relationships between the LED groups; and driving current controllers connected to the respective LED groups, for controlling the driving currents flowing in the respective LED groups to be constant currents.

Description

[Revision based on Rule 26.05.09.2017] LED lighting device and LED driving circuit thereof

Embodiment of the present invention relates to an LED driving device of the AC drive method and the LED driving circuit included therein.

In general, in order to drive an LED lighting device using an alternating voltage, a circuit is configured to convert the alternating voltage into a rectified voltage and adjust the number of LED light emitting elements that emit light as the magnitude of the rectified voltage changes.

In this case, as the size of the rectified voltage is changed, some of the plurality of LED light emitting devices continuously emit light, so that the light emitting time is determined to be long, while some of the light emitting diodes are limited to light only when the size of the rectified voltage is above a certain level. Since the light emitting time is different for each of the LED light emitting elements constituting the lighting device. As a result, some of the LED light emitting elements may first deteriorate, resulting in a poor lighting condition of the lighting device, or in some cases, the operation of the lighting device may be impossible.

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

An embodiment of the present invention is to provide a LED lighting device and a driving circuit thereof that can implement a universal voltage function without additional circuitry by controlling the connection relationship between the LED groups to correspond to the commercial AC power input.

In order to achieve the above object, the LED lighting apparatus according to the embodiment of the present invention, a rectifier for rectifying the AC voltage input from the external power source to generate a drive voltage; An LED light emitting 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 with a phase first LED group; A switch unit controller receiving the driving voltage to generate a voltage value associated with the external power source, and outputting a control signal by comparing the generated voltage value with a preset reference voltage value; A switch unit connected between the first node and a second node located between the LED groups, the switch unit being turned on / off by the control signal to change a connection relationship between the LED groups; And a driving current controller connected to the respective LED groups and configured to control the constant current of the driving current flowing through each of the LED groups.

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

In addition, 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, and a diode is further provided between the cathode end 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 ground; The voltage of the capacitor is applied to the negative input terminal, the reference voltage is applied to the positive input terminal, and comprises a comparator for comparing the output signal.

In addition, the voltage of the capacitor has a different level of voltage value for each commercial AC power corresponding to the input commercial AC power, the reference voltage is set to any effective voltage value between the commercial AC power do.

The switch unit may further 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.

In addition, the control transistor is connected between the gate electrode and the ground of the switch transistor, the control signal is applied to the gate electrode, in parallel with the resistance and the resistance connected between the drain electrode and the gate electrode of the switching transistor. A zener diode to be connected is further included.

In addition, the LED driving circuit according to the embodiment of the present invention, receives a driving voltage generated by the external power is rectified to generate a voltage value associated with the external power, and 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 a turn-on / off is controlled by the control signal to change a connection relationship between the LED groups; And a driving current controller connected to the respective LED groups and configured to control the constant current of the driving current flowing through each of the LED groups.

According to the present invention, it is possible to implement the universal voltage function without additional circuitry by controlling the connection relationship between the LED groups to correspond to the commercial AC power input.

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.

3 is a schematic circuit diagram illustrating the operation of the drive current controller shown in FIG. 1;

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 explaining the operation of the switch unit shown in FIG. 1; FIG.

Figure 6a is a block diagram illustrating the operation when the LED lighting apparatus according to an embodiment of the present invention is connected to a 120V (rms) AC power supply.

6B is a waveform diagram showing the relationship between the rectified voltage and the 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.

Figure 7a is a block diagram illustrating the operation when the LED lighting apparatus according to an embodiment of the present invention is connected to a 220V (rms) AC power source.

7B is a waveform diagram showing the relationship between the rectified voltage and the 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.

The description in the background of the technical field of the present invention is only for the purpose of understanding the background art of the technical idea of the present invention, and thus it can be understood as the content corresponding to the prior art known to those skilled in the art. none.

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

In the drawings, the size or relative size of layers, films, panels, regions, etc. may be exaggerated for clarity. Like reference numerals denote like elements.

Throughout the specification, when an element or layer is described as "connected" to another element or layer, it is not only directly connected, but also indirectly connected between other elements or layers in between. It also includes the case. 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 of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" is X one, Y one, Z one, or two of X, Y, and Z or Any combination of the above will be understood (e.g., XYZ, XYY, YZ, ZZ). Here, "and / or" includes all combinations of one or more of the configurations.

Herein, terms such as first, second, etc. may be used to describe various elements, elements, regions, layers, and / or sections, but such elements, elements, regions, layers, and / or the like. 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, the first element, element, region, layer, and / or section in one embodiment may be referred to as the second element, element, region, layer, and / or section in another embodiment.

Spatially relative terms such as "below", "above", and the like may be used for illustrative purposes, thereby describing the relationship of one device or feature to another device (s) or feature (s) as shown in the figures. do. This is only used to indicate the relationship of one component to another component in the drawings, but does not mean an absolute position. For example, when the device shown in the figures is inverted, elements depicted as being "below" of other elements or features are located in the direction of "above" other elements or features. Thus, in one embodiment the term "below" may include both up and down. In addition, the device may be in other directions (eg, rotated 90 degrees or in other directions), 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 portion "contains" a certain component, it means that it may further include other components, except to exclude other components unless specifically stated otherwise. Unless otherwise defined, terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

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

1 and 2, the LED lighting apparatus 1000 according to the embodiment of the present invention is a rectifier 100, LED light emitting unit 200, switch unit 300, switch unit controller 400, current controller 500 may be included.

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

1 illustrates an LED light emitting unit 200 including three LED groups from the first LED group 200a to the third LED group 200c, but included in the LED light emitting unit 200 as necessary. It will be apparent to those skilled in the art that the number of LED groups to be varied may vary.

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

Meanwhile, 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. For example, when the first LED group 200a to the third LED group 200c each includes a different number of LED elements, or the first LED group 200a to the third LED group 200c are each different. In the case of having a series or parallel or parallel / parallel connection relationship, the first LED group 200a to the third LED group 200c may have different forward voltage levels.

However, hereinafter, for convenience of description and understanding, the first LED group 200a to the third LED group 200c will be described based on the embodiment configured to have the same forward voltage level.

For example, the first forward voltage level Vf1 is a threshold voltage level capable of driving the first LED group 200a, and the second forward voltage level Vf2 is the first LED group 200a and the first connected in series. The threshold voltage level capable of driving the two LED groups 200b (ie, the voltage level obtained by adding the forward voltage level of the first LED group and the forward voltage level of the second LED group), and the third forward voltage level Vf3 is It may be a threshold voltage level capable of driving the first to third LED groups 200a, 200b, and 200c connected in series.

The rectifier 100 is configured to rectify the _AC voltage (V _AC ) input from the external power source 10 to generate and output a rectified voltage, the rectified voltage is a driving voltage applied to the LED light emitting unit 400 ( V _in ). As shown in FIG. 2, the rectifier 100 may employ a rectifier circuit well known in the art, such as a diode bridge circuit including diodes d1, d2, d3, and d4. The external power source 10 may be a commercial AC power source, and the commercial AC power source may be a voltage of 120 V (rms), 220 V (rms), or 277 V (rms).

The switch unit controller 400 receives a driving voltage (V _in ) and generates a voltage value associated with a commercial AC power source 10 connected to the LED lighting device 1000, and generates the preset reference voltage value. Compared to the control signal (CS) for controlling the operation of the switch unit 300 is output. However, the switch unit controller 400 may directly receive an AC voltage V _AC input from an external power source 10 _in addition to the driving voltage V _in .

As illustrated in FIG. 2, the switch unit controller 400 includes a first resistor R1 and a capacitor C connected in series between the first node N1 connected to the output terminal of the rectifier 100 and a ground. And a second resistor R2 and a zener diode dz respectively connected in parallel to the capacitor C. The apparatus may further include a comparator configured to receive a voltage applied to the capacitor C through a negative input terminal (−). In this case, 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 supply V _DC through a resistor r1 connected in series. A pull-up resistor r2 is connected to an output terminal of the comparator, and the DC power supply V _DC illustrated in FIG. 2 provides an operating voltage for operating the comparator and the regulator G. can do. In addition, the first resistor R1 and the second resistor R2 may divide the detected input voltage, and the zener diode dz may serve to protect the comparator from the input overvoltage.

The switch unit 300 performs a turn on / off operation by the control signal CS, and as illustrated, the switch unit 300 is disposed between the first node N1 and the second node N2. Connected. In this case, the first node N1 may be 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.

As illustrated in FIG. 2, the switch unit 300 includes resistors RZ connected between different types of transistors QW and QS and between the first node N1 and the gate electrode of the transistor QW, respectively. Zener diode (DZ) may be included.

According to the embodiment illustrated in FIG. 1, when the switch unit 300 is turned off, the driving voltage V _in output from the rectifier 100 is connected to the first LED group 200a to the third LED connected in series. It is sequentially applied to the 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 section (first operating period) _in which the voltage level of the driving voltage V _in is greater than or equal to the first forward voltage level Vf1 and less than the second forward voltage level Vf2. The first LED group 200a and the second LED group (in the second operation period) when the voltage level of the driving voltage V _in is greater than or equal to the second forward voltage level 2Vf and less than the third forward voltage level Vf3. 200b) is driven and the first LED group 200a, the second LED group 200b and the second LED group 200b in a section (third operating period) where the voltage level of the driving voltage V _in is greater than or equal to the third forward voltage level Vf3. All of the third LED groups 200c are driven.

On the other hand, when the switch unit 300 is turned on, the driving voltage V _in is not only the first LED group 200a connected to the first node N1 but also the second LED group connected to the second node N2 ( 200b) is also applied directly. In the embodiment illustrated in FIG. 1, the second node N2 may be a node between the cathode end of the first LED group 200a and the anode end of the second LED group 200b. In addition, when the driving voltage V _in is applied to the second node N2, the cathode terminal and the second node N2 of the first LED group 200a are illustrated to prevent generation of reverse current paths. The diode D1 may be provided between the electrodes.

As such, 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, respectively for each LED group corresponding to each set. The driving is sequentially performed according to the voltage level of the applied driving voltage V _in . The term 'set' refers to at least one LED group connected in series with each other 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. Namely, in the voltage level of the driving voltage (V _in), a first forward voltage level (Vf1) than the second forward voltage level (Vf2) lower than interval (the first operation period) is driven, only the second LED group (200b), The second LED group 200b and the third LED group (in the second operation period) when the voltage level of the driving voltage V _in is greater than or equal to the second forward voltage level Vf2 and less than the third forward voltage level Vf3. 200c) may be driven.

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

The current controller 500 includes a plurality of driving current controllers 500a, 500b, and 500c. 1 includes first to third drive current controllers 500a, 500b and 500c, which are connected to the cathode ends of the first LED group 200a to the third LED group 200c, respectively. . A target voltage Vt may be applied to each of the driving current controllers 500a, 500b, and 500c, and may be applied to the first to third driving current controllers 500a, 500b, and 500c according to the target voltage Vt. The amount of current of the connected first to third LED groups 200a, 200b, and 200c is determined, respectively. Accordingly, the first to third driving current controllers 500a, 500b, and 500c perform an 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 driving current controllers 500a, 500b, and 500c, and in this case, the first to third driving currents may be constant current controlled according to a preset value.

Each of the driving current controllers 500a, 500b, and 500c may include a transistor Qd, a sense resistor Rd, and a linear amplifier as shown in FIG. 2.

The LED lighting apparatus 1000 according to the embodiment of the present invention detects a voltage level corresponding to the input commercial AC power supply 10 and according to the detected voltage level, the LED light emitting device groups 200a, 200b, and 200c. By performing the operation of controlling the connection between the two, it is possible to implement a universal voltage (universal voltage) function without additional circuitry.

In addition, the switch unit controller 400, the switch unit 300, and the current controller 500 may be integrated into one IC, which receives the driving voltage V _in to receive the LED light emitting unit 200. It can serve as a driving LED driving circuit.

Hereinafter, each embodiment of the current controller 500, the switch unit controller 400, and the switch unit 300 among the components constituting the LED driving circuit will be described with reference to FIGS. 3 to 5.

FIG. 3 is a schematic circuit diagram illustrating the operation of the driving current controller shown in FIG. 1. 3 illustrates the first driving current controller 500a as an example, the second and third driving current controllers may be configured in the same manner.

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 may be 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. Do this.

The transistor Qd and the linear amplifier 520 constitute a feedback circuit. If the detection voltage at the detection resistor Rd is less than the target voltage Vt, the linear amplifier 520 is at a high level voltage (i.e. , A positive voltage), which is applied to the gate electrode of transistor Qd.

As an exemplary embodiment, the first driving current controller 500a may be disposed in a section (first operating period) _in which the voltage level of the driving voltage V _in is greater than or equal to the first forward voltage level 1Vf and less than the second forward voltage level 2Vf. The operation of is as follows.

The first LED group 200a is turned on in the first operation period, and the first driving current controller 500a connected to the first LED group 200a is also activated to flow through the first LED group 200a. One LED current I _LED1 is applied to the detection resistor Rd of the first driving current controller 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 converts the first gate input voltage V _G1 corresponding to the difference into a transistor ( Output to the gate electrode of Qd). As mentioned above, when the detection voltage is less than the target voltage Vt, the voltage V _G1 has a high level voltage value.

In this case, the voltage V _GS between the gate electrode and the source electrode of the transistor Qd is changed by the first gate input voltage V _G1 , and the transistor Qd is turned on / off according to the voltage V _GS. The off state is determined.

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

That is, the voltage at the detection resistor Rd has a characteristic of following the target voltage Vt, and thus the first LED current I _LED1 can be controlled as a constant current.

FIG. 4 is a schematic circuit diagram illustrating the operation of the switch unit controller shown in FIG. 1. 4 illustrates only a basic configuration for explaining the operation of the switch unit controller, and other components may be further included.

Referring to FIG. 4, the switch unit controller 400 receives a driving voltage V _in to generate a voltage Vc associated with a commercial AC power source 10 connected to the LED lighting apparatus 1000. 410 and a comparator 420 for outputting a control signal CS for controlling the operation of the switch unit 300 by comparing the generated voltage Vc with a preset reference voltage V _REF . 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 standard of the commercial AC power supply 10 to which the LED lighting device 2000 is connected in order to implement the aforementioned universal voltage function, and the LED under the detected AC power supply standard. The light emitting unit 200 controls the connection relationship between the first LED group 200a to the third LED group 200c to smoothly drive the light emitting unit 200.

For example, the LED light emitting unit 200 including the first to third LED groups 200a, 200b, and 200c includes a first forward voltage level Vf1 of 60V and a second forward voltage level of 120V ( It is assumed that Vf2) is configured to have a third forward voltage level Vf3 of 160V. In this case, when the LED driving apparatus 1000 of the AC driving method is connected to a 220V (rms) or 277V (rms) AC power source, the first to third LED groups 200a, 200b, and 200c are connected in series. Although all may operate in a state, when the LED driving apparatus 1000 of the AC driving method is connected to an AC power supply of 120V (rms), the first to third LED groups 200a, 200b, and 200c are in series with each other. You can't operate all of them while connected That is, when connected to an AC power supply of 120 V (rms), the third LED group 200c among the first to third LED groups 200a, 200b, and 200c connected in series with each other may not emit light continuously. .

Conversely, the connection is divided into a first set of LED groups (first LED group 200a) and a second set of LED groups (second LED group 200b and 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 220V (rms) or 277V (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 ) and generates a voltage (Vc) associated with a commercial AC power source 10 connected to the LED lighting apparatus 1000, and the preset voltage is set in advance. Compared to the reference voltage (V _REF ) can determine the specification of the commercial AC power supply currently connected.

As shown in FIG. 4, the voltage generator 410 includes a resistor R and a capacitor C connected in series between the first node N1 and the ground. The 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 and outputs the voltage Vc of the capacitor C to the negative input terminal of the comparator 420. The voltage generator 410 may convert a waveform of an input AC voltage to generate a voltage signal Vc maintaining a constant level. 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 a different waveform according to an external power source 10, that is, a commercial AC power source, and the voltage Vc generated by the voltage generator 410 may be input. In response to the commercial AC power source has a different level of voltage value.

For example, when an AC power source of 120V (rms) is input, a signal Vc1 having a first voltage level is generated. When an AC power source of 220V (rms) is input, a signal Vc2 having a second voltage level is generated. When an AC power source of 277V (rms) is input, a signal Vc3 having a third voltage level may be generated.

Accordingly, the voltage Vc generated by the voltage generator 410 is a voltage associated with the commercial AC power inputted therein, thereby determining the input AC power.

According to the above-described embodiment, when 220V (rms) or 277V (rms) AC power is connected, the first LED group to the third LED group 200a, 200b, 200c are sequentially driven in series with each other. When connected to an AC power supply of 120V (rms), the first set of LED groups (first LED group 200a) and the second set of LED groups (second LED group 200b and third LEDs connected in series with each other) The connection relationship is preferably controlled to be divided into groups 200c).

According to the configuration of the switch unit controller 400 shown in FIG. 4, the driving voltage V _in is received to generate a voltage Vc associated with a commercial AC power source connected to the LED lighting apparatus 1000, and the generated voltage It may be configured to compare (Vc) with a predetermined 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 a commercial AC power source for controlling the connection relationship between the first LED group and the third LED group 200a, 200b, 200c. That is, the LED lighting apparatus 1000 is connected to the AC power is large enough to drive the first LED group to the third LED group (200a, 200b, 200c) connected in series with each other or the first LED group to the third LED It may be configured to judge only if it is small enough to drive the groups 200a, 200b, 200c into a plurality of sets, and to control the operation of the switch unit 300 based on such determination.

For example, as described above (the LED light emitting unit 200 is the first forward voltage level Vf1 of 60V, the second forward voltage level Vf2 of 120V, and the third forward voltage level Vf3 of 160V). If the AC power connected is 220V (rms) or 277V (rms), the first LED group to the third LED group (200a, 200b, 200c) can be driven in series with each other, When the AC power source is 120V (rms), the first set of LED groups (first LED group 200a) and the second set of LED groups (second LED group 200b and third LED group connected in series with each other) 200c)).

For example, the reference voltage V _REF may be set to correspond to any reference effective voltage (eg, 200 V (rms)) between 120 V (rms) and 220 V (rms), and the voltage generator ( By comparing the voltages Vc1, Vc2, and Vc3 generated at 400, the currently connected commercial AC power source may be determined.

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

FIG. 5 is a schematic circuit diagram illustrating an operation of the switch unit shown in FIG. 1.

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

The drain electrode of the switching transistor QW may be connected to the driving voltage V _in through the first node N1, and a resistor RZ may be connected between the drain electrode and the gate electrode. The switching operation of the switching transistor QW may 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 may serve to clip the gate electrode to a predetermined level when a surge voltage of a high voltage is instantaneously applied.

The source electrode of the switching transistor QW is connected to the second node N2, and the second node N2 is the cathode terminal of the first LED group 200a and the second LED group 200b as shown in FIG. 1. Can be a node between the anode ends of

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.

The operation of the switch unit 300 is controlled by the control signal CS as follows.

When the control signal CS reaches a low level, for example, when the input AC power is determined to be 220V (rms) or 277V (rms), the control transistor QS is turned on, and accordingly, the switching transistor QW is turned on. The low voltage is applied to the gate electrode of the gate electrode by the 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 the high level, the control transistor QS is turned off when the AC power input as an example is determined to be 120V (rms). In addition, a voltage of a predetermined level is applied to the switching transistor QW due to the resistor RZ connected between the gate electrode and the drain electrode of the switching transistor QW. In particular, the current path through the driving voltage V _in and the resistor RZ is blocked by the control transistor QS in the cut-off state. Therefore, since the same level as the driving voltage V _in is applied to the gate electrode of the switching transistor QW, the switching transistor QW is turned on. When the switching transistor QW is turned on, the first set of LED groups (first LED group 200a) and the second set of LED groups (second LED group 200b and third LED group connected in series with each other). Connection (200c) is formed.

Figure 6a is a block diagram illustrating the operation when the LED lighting apparatus according to an embodiment of the present invention is connected to 120V (rms) AC power, Figure 6b is a 120V (rms) LED lighting apparatus according to an embodiment of the present invention This waveform diagram shows the relationship between the rectified voltage and the LED drive current when connected to an AC power source.

6A and 6B, as described above, the LED light emitting unit 200 includes the first forward voltage level Vf1 of 60V, the second forward voltage level Vf2 of 120V, and the third of 160V. Assume that it is configured to have a forward voltage level (Vf3).

Hereinafter, referring to FIGS. 6A and 6B, the operation when the LED lighting apparatus 1000 is connected to a 120V (rms) AC power source will be described.

As described above, the 120V (rms) AC power supply cannot sequentially drive the first LED group to the third LED group 200a, 200b, 200c in series with each other. Therefore, when the 120V (rms) AC power is connected, the switch unit 300 is turned on by the switch unit controller 400 so that one set of LED groups (first LED group 200a) and a second set of LEDs are turned on. The state divided into groups (second LED group 200b to 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. At the bottom of 6b, LED driving currents I _LED2 and I flowing through the driving voltage V _in and the second set of LED groups, that is, the second LED group 200b and the third LED group 200c connected in series with each other. The relationship of _LED3 ) is shown.

As can be seen at the top and bottom of FIG. 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 .

More specifically, referring to FIGS. 6A and 6B, the driving voltage V _in is not only the first LED group 200a connected to the first node N1 but also the second LED group connected to the second node N2. Directly applied to 200b.

As such, 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, respectively for each LED group corresponding to each set. The driving is sequentially performed according to the voltage level of the applied driving voltage V _in .

That is, the second LED in the section (first operating period, t1 ~ t2, t3 ~ t4) where the voltage level of the driving voltage (V _in ) is greater than the first forward voltage level (1Vf) or less than the second forward voltage level (2Vf). Only the group 200b is driven so that the second LED current I _LED2 flows (2 in FIG. 6A).

The second LED group 200b and the second LED in the period (second operation period, t2 to t3) where the voltage level of the driving voltage V _in is greater than or equal to the second forward voltage level 2Vf and less than the third forward voltage level 3Vf. The 3 LED group 200c is driven to flow the third LED current I _LED3 (3 in FIG. 6A).

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

Figure 7a is a block diagram illustrating the operation when the LED lighting apparatus according to an embodiment of the present invention is connected to a 220V (rms) AC power source, Figure 7b is a 220V (rms) LED lighting apparatus according to an embodiment of the present invention This waveform diagram shows the relationship between the rectified voltage and the LED drive current when connected to an AC power source.

7A and 7B, as described above, the LED light emitting unit 200 includes a first forward voltage level Vf1 of 60V, a second forward voltage level Vf2 of 120V, and a second voltage of 160V. Assume that it is configured to have three forward voltage levels (Vf3).

Hereinafter, referring to FIGS. 7A and 7B, the operation when the LED lighting apparatus 1000 is connected to a 220V (rms) AC power source will be described.

As described above, the 220V (rms) AC power source may sequentially drive the first to third LED groups 200a, 200b, and 200c in series with each other.

Therefore, when the 220V (rms) AC power is connected, the switch unit 300 is turned off by the switch unit controller 400, and the first to third LED groups 200a, 200b, and 200c are in series with each other. It is sequentially driven in the connected state. 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. It is sequentially driven according to the voltage level of the voltage V _in .

For example, a section _in which the voltage level of the driving voltage V _in is greater than or equal to the first forward voltage level 1Vf and less than the second forward voltage level 2Vf (first operating period, t1 'to t2', t5 'to t6'). In FIG. 7, only the first LED group 200a is driven to flow the first LED current I _{LED1 ′} (1 ′ in FIG. 7A).

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

The first LED group 200a, the second LED group 200b, and the second LED group 200b in a section (third operating period, t3 'to t4') where the voltage level of the driving voltage V _in is greater than or equal to the third forward voltage level 3Vf. the 3 LED groups (200c) are all _driven, it flows (Fig. 7a ③ claim 3 LED current (I _LED3) '). In addition, in the exemplary embodiment of the present invention, the size of the LED driving current I _LED may be controlled for each AC power so that the power deviation of the input power input to the AC power may be maintained within 10% to 30%. For example, 220V (rms) LED lighting apparatus 1000 of the LED driving current (I _LED ') is a 120V (rms) LED drive current (I _LED) of the LED lighting apparatus 1000 is connected to the AC power to the AC power source Constant current can be controlled to about 1/2. 6A and 6B, a first LED driving current I _LED1 , a second LED driving current I _LED2 , and a third LED driving current I _LED3 of the LED lighting apparatus 1000 connected to a 120V (rms) AC power source. 7A and 7B, a first LED driving current I _LED1 ′, a second LED driving current I _LED2 ′, and a third LED of the LED lighting apparatus 1000 connected to a 220V (rms) AC power source are shown. LED drive current I _LED3 ′ is shown.

6B and 7B, the magnitude of the first LED driving current I _LED1 ′, the magnitude of the second LED driving current I _LED2 ′ and the third LED driving current when connected to a 220V (rms) AC power source. The size of (I _LED3 ′) is the magnitude of the first LED driving current (I _LED1 ), the magnitude of the second LED driving current (I _LED2 ), and the third LED driving current (I _It can be seen that the constant current is controlled to about 1/2 the size of _LED3 ).

In the present invention as described above has been described by the specific embodiments, such as specific components and limited embodiments and drawings, but this is provided to help a more general understanding of the present invention, the present invention is not limited to the above embodiments. For those skilled in the art, various modifications and variations are possible from these descriptions.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all the things that are equivalent to or equivalent to the claims as well as the following claims will belong to the scope of the present invention. .

According to the present invention, it is possible to implement the universal voltage function without additional circuitry by controlling the connection relationship between the LED groups to correspond to the commercial AC power input.

Claims (20)

1. A rectifier for rectifying an AC voltage input from an external power source to generate a driving voltage;

   An LED light emitting 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 with a phase first LED group;

   A switch unit controller receiving the driving voltage to generate a voltage value associated with the external power source, and outputting a control signal by comparing the generated voltage value with a preset reference voltage value;

   A switch unit connected between the first node and a second node located between the LED groups, the switch unit being turned on / off by the control signal to change a connection relationship between the LED groups;

   And a driving current controller connected to the respective LED groups and configured to control the constant current of the driving current flowing through each of the LED groups.
2. The method of claim 1,

   The external power source is an LED lighting device is one of commercial AC power source having a different effective voltage value.
3. The method of claim 1,

   And 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.
4. The method of claim 3, wherein

   LED lighting device is further provided between the cathode end of the first LED group and the second node.
5. The method of claim 1,

   The switch unit controller,

   A resistor and a capacitor connected in series between the first node and ground;

   The voltage of the capacitor is applied to the negative input terminal, the reference voltage is applied to the positive input terminal, LED lighting device comprising a comparator for comparing the output and the control signal.
6. The method of claim 5,

   The voltage of the capacitor is LED lighting device having a voltage value of a different level for each commercial AC power in response to the input commercial AC power.
7. The method of claim 6,

   And the reference voltage is set to an arbitrary effective voltage value between the commercial AC power supplies.
8. The method of claim 1,

   The switch unit,

   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,

   The control transistor is connected between the gate electrode and the ground of the switch transistor, the LED lighting device to which the control signal is applied to the gate electrode.
10. The method of claim 8,

    LED lighting device further comprises a resistor connected between the drain electrode and the gate electrode of the switching transistor and a Zener diode connected in parallel with the resistance.
11. A switch unit controller receiving a driving voltage generated by rectifying an external power source, generating a voltage value associated with the external power source, and outputting a control signal by comparing the generated voltage value with a preset reference voltage value;

    A switch unit connected between a first node to which the driving voltage is applied and a second node between the LED groups, and a turn-on / off is controlled by the control signal to change a connection relationship between the LED groups;

    And a driving current controller connected to the respective LED groups and configured to control the constant current of the driving current flowing through each of the LED groups.
12. The method of claim 11,

    The external power source is a LED driving circuit of one of commercial AC power source having a different effective voltage value.
13. The method of claim 1,

    And 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,

    LED driving circuit further comprises a diode between the cathode terminal of the first LED group and the second node.
15. The method of claim 11,

    The switch unit controller,

    A resistor and a capacitor connected in series between the first node and ground;

    And a comparator for applying a voltage of the capacitor to a negative input terminal, a reference voltage to a positive input terminal, and comparing the same and outputting the control signal.
16. The method of claim 15,

    The voltage of the capacitor LED driving circuit having a voltage level of a different level for each commercial AC power in response to the input commercial AC power.
17. The method of claim 16,

    And the reference voltage is set to an arbitrary effective voltage value between the commercial AC power supplies.
18. The method of claim 11,

    The switch unit,

    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,

    The control transistor is connected between the gate electrode and the ground of the switch transistor, the LED driving circuit to which the control signal is applied to the gate electrode.
20. The method of claim 18,

    The LED driving circuit further comprises a resistor connected between the drain electrode and the gate electrode of the switching transistor and a Zener diode connected in parallel with the resistance.

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